Upgrade to 2022-era LLVM LIBCXX

third_party/libcxx/__algorithm/adjacent_find.h

@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ADJACENT_FIND_H
+#define _LIBCPP___ALGORITHM_ADJACENT_FIND_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/iterator_operations.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Iter, class _Sent, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter
+__adjacent_find(_Iter __first, _Sent __last, _BinaryPredicate&& __pred) {
+  if (__first == __last)
+    return __first;
+  _Iter __i = __first;
+  while (++__i != __last) {
+    if (__pred(*__first, *__i))
+      return __first;
+    __first = __i;
+  }
+  return __i;
+}
+
+template <class _ForwardIterator, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred) {
+  return std::__adjacent_find(std::move(__first), std::move(__last), __pred);
+}
+
+template <class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+adjacent_find(_ForwardIterator __first, _ForwardIterator __last) {
+  return std::adjacent_find(std::move(__first), std::move(__last), __equal_to());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ADJACENT_FIND_H

third_party/libcxx/__algorithm/all_of.h

@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ALL_OF_H
+#define _LIBCPP___ALGORITHM_ALL_OF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  for (; __first != __last; ++__first)
+    if (!__pred(*__first))
+      return false;
+  return true;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ALL_OF_H

third_party/libcxx/__algorithm/any_of.h

@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ANY_OF_H
+#define _LIBCPP___ALGORITHM_ANY_OF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  for (; __first != __last; ++__first)
+    if (__pred(*__first))
+      return true;
+  return false;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ANY_OF_H

third_party/libcxx/__algorithm/binary_search.h

@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_BINARY_SEARCH_H
+#define _LIBCPP___ALGORITHM_BINARY_SEARCH_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/lower_bound.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp)
+{
+    __first = std::lower_bound<_ForwardIterator, _Tp, __comp_ref_type<_Compare> >(__first, __last, __value, __comp);
+    return __first != __last && !__comp(__value, *__first);
+}
+
+template <class _ForwardIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
+{
+    return std::binary_search(__first, __last, __value,
+                              __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_BINARY_SEARCH_H

third_party/libcxx/__algorithm/clamp.h

@@ -0,0 +1,46 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_CLAMP_H
+#define _LIBCPP___ALGORITHM_CLAMP_H
+
+#include <__algorithm/comp.h>
+#include <__assert>
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 17
+template<class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY constexpr
+const _Tp&
+clamp(const _Tp& __v, const _Tp& __lo, const _Tp& __hi, _Compare __comp)
+{
+    _LIBCPP_ASSERT(!__comp(__hi, __lo), "Bad bounds passed to std::clamp");
+    return __comp(__v, __lo) ? __lo : __comp(__hi, __v) ? __hi : __v;
+
+}
+
+template<class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY constexpr
+const _Tp&
+clamp(const _Tp& __v, const _Tp& __lo, const _Tp& __hi)
+{
+    return _VSTD::clamp(__v, __lo, __hi, __less<_Tp>());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_CLAMP_H

third_party/libcxx/__algorithm/comp.h

@@ -0,0 +1,71 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COMP_H
+#define _LIBCPP___ALGORITHM_COMP_H
+
+#include <__config>
+#include <__type_traits/integral_constant.h>
+#include <__type_traits/predicate_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct __equal_to {
+  template <class _T1, class _T2>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _T1& __x, const _T2& __y) const {
+    return __x == __y;
+  }
+};
+
+template <class _Lhs, class _Rhs>
+struct __is_trivial_equality_predicate<__equal_to, _Lhs, _Rhs> : true_type {};
+
+template <class _T1, class _T2 = _T1>
+struct __less
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+    bool operator()(const _T1& __x, const _T2& __y) const {return __x < __y;}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+    bool operator()(const _T2& __x, const _T1& __y) const {return __x < __y;}
+
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+    bool operator()(const _T2& __x, const _T2& __y) const {return __x < __y;}
+};
+
+template <class _T1>
+struct __less<_T1, _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+};
+
+template <class _T1>
+struct __less<const _T1, _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+};
+
+template <class _T1>
+struct __less<_T1, const _T1>
+{
+    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COMP_H

third_party/libcxx/__algorithm/comp_ref_type.h

@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COMP_REF_TYPE_H
+#define _LIBCPP___ALGORITHM_COMP_REF_TYPE_H
+
+#include <__config>
+#include <__debug>
+#include <__utility/declval.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare>
+struct __debug_less
+{
+    _Compare &__comp_;
+    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI __debug_less(_Compare& __c) : __comp_(__c) {}
+
+    template <class _Tp, class _Up>
+    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI
+    bool operator()(const _Tp& __x,  const _Up& __y)
+    {
+        bool __r = __comp_(__x, __y);
+        if (__r)
+            __do_compare_assert(0, __y, __x);
+        return __r;
+    }
+
+    template <class _Tp, class _Up>
+    _LIBCPP_CONSTEXPR_SINCE_CXX14 _LIBCPP_HIDE_FROM_ABI
+    bool operator()(_Tp& __x,  _Up& __y)
+    {
+        bool __r = __comp_(__x, __y);
+        if (__r)
+            __do_compare_assert(0, __y, __x);
+        return __r;
+    }
+
+    template <class _LHS, class _RHS>
+    _LIBCPP_CONSTEXPR_SINCE_CXX14
+    inline _LIBCPP_INLINE_VISIBILITY
+    decltype((void)std::declval<_Compare&>()(
+        std::declval<_LHS &>(), std::declval<_RHS &>()))
+    __do_compare_assert(int, _LHS & __l, _RHS & __r) {
+        _LIBCPP_DEBUG_ASSERT(!__comp_(__l, __r),
+            "Comparator does not induce a strict weak ordering");
+        (void)__l;
+        (void)__r;
+    }
+
+    template <class _LHS, class _RHS>
+    _LIBCPP_CONSTEXPR_SINCE_CXX14
+    inline _LIBCPP_INLINE_VISIBILITY
+    void __do_compare_assert(long, _LHS &, _RHS &) {}
+};
+
+// Pass the comparator by lvalue reference. Or in debug mode, using a
+// debugging wrapper that stores a reference.
+#ifdef _LIBCPP_ENABLE_DEBUG_MODE
+template <class _Comp>
+using __comp_ref_type = __debug_less<_Comp>;
+#else
+template <class _Comp>
+using __comp_ref_type = _Comp&;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COMP_REF_TYPE_H

third_party/libcxx/__algorithm/copy.h

@@ -0,0 +1,124 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COPY_H
+#define _LIBCPP___ALGORITHM_COPY_H
+
+#include <__algorithm/copy_move_common.h>
+#include <__algorithm/for_each_segment.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/min.h>
+#include <__config>
+#include <__iterator/segmented_iterator.h>
+#include <__type_traits/common_type.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class, class _InIter, class _Sent, class _OutIter>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter> __copy(_InIter, _Sent, _OutIter);
+
+template <class _AlgPolicy>
+struct __copy_loop {
+  template <class _InIter, class _Sent, class _OutIter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _Sent __last, _OutIter __result) const {
+    while (__first != __last) {
+      *__result = *__first;
+      ++__first;
+      ++__result;
+    }
+
+    return std::make_pair(std::move(__first), std::move(__result));
+  }
+
+  template <class _InIter, class _OutIter>
+  struct _CopySegment {
+    using _Traits = __segmented_iterator_traits<_InIter>;
+
+    _OutIter& __result_;
+
+    _LIBCPP_HIDE_FROM_ABI _CopySegment(_OutIter& __result) : __result_(__result) {}
+
+    _LIBCPP_HIDE_FROM_ABI void
+    operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
+      __result_ = std::__copy<_AlgPolicy>(__lfirst, __llast, std::move(__result_)).second;
+    }
+  };
+
+  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
+    std::__for_each_segment(__first, __last, _CopySegment<_InIter, _OutIter>(__result));
+    return std::make_pair(__last, std::move(__result));
+  }
+
+  template <class _InIter,
+            class _OutIter,
+            __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
+                              !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
+                          int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) {
+    using _Traits = __segmented_iterator_traits<_OutIter>;
+    using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
+
+    if (__first == __last)
+      return std::make_pair(std::move(__first), std::move(__result));
+
+    auto __local_first      = _Traits::__local(__result);
+    auto __segment_iterator = _Traits::__segment(__result);
+    while (true) {
+      auto __local_last = _Traits::__end(__segment_iterator);
+      auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
+      auto __iters      = std::__copy<_AlgPolicy>(__first, __first + __size, __local_first);
+      __first           = std::move(__iters.first);
+
+      if (__first == __last)
+        return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
+
+      __local_first = _Traits::__begin(++__segment_iterator);
+    }
+  }
+};
+
+struct __copy_trivial {
+  // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
+  template <class _In, class _Out, __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+  operator()(_In* __first, _In* __last, _Out* __result) const {
+    return std::__copy_trivial_impl(__first, __last, __result);
+  }
+};
+
+template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
+pair<_InIter, _OutIter> inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+__copy(_InIter __first, _Sent __last, _OutIter __result) {
+  return std::__dispatch_copy_or_move<_AlgPolicy, __copy_loop<_AlgPolicy>, __copy_trivial>(
+      std::move(__first), std::move(__last), std::move(__result));
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
+  return std::__copy<_ClassicAlgPolicy>(__first, __last, __result).second;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_COPY_H

third_party/libcxx/__algorithm/copy_backward.h

@@ -0,0 +1,143 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COPY_BACKWARD_H
+#define _LIBCPP___ALGORITHM_COPY_BACKWARD_H
+
+#include <__algorithm/copy_move_common.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/min.h>
+#include <__config>
+#include <__iterator/segmented_iterator.h>
+#include <__type_traits/common_type.h>
+#include <__type_traits/is_copy_constructible.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InIter, _OutIter>
+__copy_backward(_InIter __first, _Sent __last, _OutIter __result);
+
+template <class _AlgPolicy>
+struct __copy_backward_loop {
+  template <class _InIter, class _Sent, class _OutIter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _Sent __last, _OutIter __result) const {
+    auto __last_iter          = _IterOps<_AlgPolicy>::next(__first, __last);
+    auto __original_last_iter = __last_iter;
+
+    while (__first != __last_iter) {
+      *--__result = *--__last_iter;
+    }
+
+    return std::make_pair(std::move(__original_last_iter), std::move(__result));
+  }
+
+  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
+    using _Traits = __segmented_iterator_traits<_InIter>;
+    auto __sfirst = _Traits::__segment(__first);
+    auto __slast  = _Traits::__segment(__last);
+    if (__sfirst == __slast) {
+      auto __iters =
+          std::__copy_backward<_AlgPolicy>(_Traits::__local(__first), _Traits::__local(__last), std::move(__result));
+      return std::make_pair(__last, __iters.second);
+    }
+
+    __result =
+        std::__copy_backward<_AlgPolicy>(_Traits::__begin(__slast), _Traits::__local(__last), std::move(__result))
+            .second;
+    --__slast;
+    while (__sfirst != __slast) {
+      __result =
+          std::__copy_backward<_AlgPolicy>(_Traits::__begin(__slast), _Traits::__end(__slast), std::move(__result))
+              .second;
+      --__slast;
+    }
+    __result = std::__copy_backward<_AlgPolicy>(_Traits::__local(__first), _Traits::__end(__slast), std::move(__result))
+                   .second;
+    return std::make_pair(__last, std::move(__result));
+  }
+
+  template <class _InIter,
+            class _OutIter,
+            __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
+                              !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
+                          int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) {
+    using _Traits           = __segmented_iterator_traits<_OutIter>;
+    auto __orig_last        = __last;
+    auto __segment_iterator = _Traits::__segment(__result);
+
+    // When the range contains no elements, __result might not be a valid iterator
+    if (__first == __last)
+      return std::make_pair(__first, __result);
+
+    auto __local_last = _Traits::__local(__result);
+    while (true) {
+      using _DiffT = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
+
+      auto __local_first = _Traits::__begin(__segment_iterator);
+      auto __size        = std::min<_DiffT>(__local_last - __local_first, __last - __first);
+      auto __iter        = std::__copy_backward<_AlgPolicy>(__last - __size, __last, __local_last).second;
+      __last -= __size;
+
+      if (__first == __last)
+        return std::make_pair(std::move(__orig_last), _Traits::__compose(__segment_iterator, std::move(__iter)));
+      --__segment_iterator;
+      __local_last = _Traits::__end(__segment_iterator);
+    }
+  }
+};
+
+struct __copy_backward_trivial {
+  // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
+  template <class _In, class _Out,
+            __enable_if_t<__can_lower_copy_assignment_to_memmove<_In, _Out>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+  operator()(_In* __first, _In* __last, _Out* __result) const {
+    return std::__copy_backward_trivial_impl(__first, __last, __result);
+  }
+};
+
+template <class _AlgPolicy, class _BidirectionalIterator1, class _Sentinel, class _BidirectionalIterator2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_BidirectionalIterator1, _BidirectionalIterator2>
+__copy_backward(_BidirectionalIterator1 __first, _Sentinel __last, _BidirectionalIterator2 __result) {
+  return std::__dispatch_copy_or_move<_AlgPolicy, __copy_backward_loop<_AlgPolicy>, __copy_backward_trivial>(
+      std::move(__first), std::move(__last), std::move(__result));
+}
+
+template <class _BidirectionalIterator1, class _BidirectionalIterator2>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+_BidirectionalIterator2
+copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
+              _BidirectionalIterator2 __result)
+{
+  static_assert(std::is_copy_constructible<_BidirectionalIterator1>::value &&
+                std::is_copy_constructible<_BidirectionalIterator1>::value, "Iterators must be copy constructible.");
+
+  return std::__copy_backward<_ClassicAlgPolicy>(
+      std::move(__first), std::move(__last), std::move(__result)).second;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_COPY_BACKWARD_H

third_party/libcxx/__algorithm/copy_if.h

@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COPY_IF_H
+#define _LIBCPP___ALGORITHM_COPY_IF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _InputIterator, class _OutputIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+_OutputIterator
+copy_if(_InputIterator __first, _InputIterator __last,
+        _OutputIterator __result, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+    {
+        if (__pred(*__first))
+        {
+            *__result = *__first;
+            ++__result;
+        }
+    }
+    return __result;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COPY_IF_H

third_party/libcxx/__algorithm/copy_move_common.h

@@ -0,0 +1,163 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H
+#define _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H
+
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/unwrap_iter.h>
+#include <__algorithm/unwrap_range.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__memory/pointer_traits.h>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_always_bitcastable.h>
+#include <__type_traits/is_constant_evaluated.h>
+#include <__type_traits/is_copy_constructible.h>
+#include <__type_traits/is_trivially_assignable.h>
+#include <__type_traits/is_trivially_copyable.h>
+#include <__type_traits/is_volatile.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Type traits.
+
+template <class _From, class _To>
+struct __can_lower_copy_assignment_to_memmove {
+  static const bool value =
+    // If the types are always bitcastable, it's valid to do a bitwise copy between them.
+    __is_always_bitcastable<_From, _To>::value &&
+    // Reject conversions that wouldn't be performed by the regular built-in assignment (e.g. between arrays).
+    is_trivially_assignable<_To&, const _From&>::value &&
+    // `memmove` doesn't accept `volatile` pointers, make sure the optimization SFINAEs away in that case.
+    !is_volatile<_From>::value &&
+    !is_volatile<_To>::value;
+};
+
+template <class _From, class _To>
+struct __can_lower_move_assignment_to_memmove {
+  static const bool value =
+    __is_always_bitcastable<_From, _To>::value &&
+    is_trivially_assignable<_To&, _From&&>::value &&
+    !is_volatile<_From>::value &&
+    !is_volatile<_To>::value;
+};
+
+// `memmove` algorithms implementation.
+
+template <class _In, class _Out>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+__copy_trivial_impl(_In* __first, _In* __last, _Out* __result) {
+  const size_t __n = static_cast<size_t>(__last - __first);
+  ::__builtin_memmove(__result, __first, __n * sizeof(_Out));
+
+  return std::make_pair(__last, __result + __n);
+}
+
+template <class _In, class _Out>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+__copy_backward_trivial_impl(_In* __first, _In* __last, _Out* __result) {
+  const size_t __n = static_cast<size_t>(__last - __first);
+  __result -= __n;
+
+  ::__builtin_memmove(__result, __first, __n * sizeof(_Out));
+
+  return std::make_pair(__last, __result);
+}
+
+// Iterator unwrapping and dispatching to the correct overload.
+
+template <class _F1, class _F2>
+struct __overload : _F1, _F2 {
+  using _F1::operator();
+  using _F2::operator();
+};
+
+template <class _InIter, class _Sent, class _OutIter, class = void>
+struct __can_rewrap : false_type {};
+
+template <class _InIter, class _Sent, class _OutIter>
+struct __can_rewrap<_InIter,
+                    _Sent,
+                    _OutIter,
+                    // Note that sentinels are always copy-constructible.
+                    __enable_if_t< is_copy_constructible<_InIter>::value &&
+                                   is_copy_constructible<_OutIter>::value > > : true_type {};
+
+template <class _Algorithm,
+          class _InIter,
+          class _Sent,
+          class _OutIter,
+          __enable_if_t<__can_rewrap<_InIter, _Sent, _OutIter>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter>
+__unwrap_and_dispatch(_InIter __first, _Sent __last, _OutIter __out_first) {
+  auto __range  = std::__unwrap_range(__first, std::move(__last));
+  auto __result = _Algorithm()(std::move(__range.first), std::move(__range.second), std::__unwrap_iter(__out_first));
+  return std::make_pair(std::__rewrap_range<_Sent>(std::move(__first), std::move(__result.first)),
+                                 std::__rewrap_iter(std::move(__out_first), std::move(__result.second)));
+}
+
+template <class _Algorithm,
+          class _InIter,
+          class _Sent,
+          class _OutIter,
+          __enable_if_t<!__can_rewrap<_InIter, _Sent, _OutIter>::value, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter>
+__unwrap_and_dispatch(_InIter __first, _Sent __last, _OutIter __out_first) {
+  return _Algorithm()(std::move(__first), std::move(__last), std::move(__out_first));
+}
+
+template <class _IterOps, class _InValue, class _OutIter, class = void>
+struct __can_copy_without_conversion : false_type {};
+
+template <class _IterOps, class _InValue, class _OutIter>
+struct __can_copy_without_conversion<
+    _IterOps,
+    _InValue,
+    _OutIter,
+    __enable_if_t<is_same<_InValue, typename _IterOps::template __value_type<_OutIter> >::value> > : true_type {};
+
+template <class _AlgPolicy,
+          class _NaiveAlgorithm,
+          class _OptimizedAlgorithm,
+          class _InIter,
+          class _Sent,
+          class _OutIter>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pair<_InIter, _OutIter>
+__dispatch_copy_or_move(_InIter __first, _Sent __last, _OutIter __out_first) {
+#ifdef _LIBCPP_COMPILER_GCC
+  // GCC doesn't support `__builtin_memmove` during constant evaluation.
+  if (__libcpp_is_constant_evaluated()) {
+    return std::__unwrap_and_dispatch<_NaiveAlgorithm>(std::move(__first), std::move(__last), std::move(__out_first));
+  }
+#else
+  // In Clang, `__builtin_memmove` only supports fully trivially copyable types (just having trivial copy assignment is
+  // insufficient). Also, conversions are not supported.
+  if (__libcpp_is_constant_evaluated()) {
+    using _InValue = typename _IterOps<_AlgPolicy>::template __value_type<_InIter>;
+    if (!is_trivially_copyable<_InValue>::value ||
+        !__can_copy_without_conversion<_IterOps<_AlgPolicy>, _InValue, _OutIter>::value) {
+      return std::__unwrap_and_dispatch<_NaiveAlgorithm>(std::move(__first), std::move(__last), std::move(__out_first));
+    }
+  }
+#endif // _LIBCPP_COMPILER_GCC
+
+  using _Algorithm = __overload<_NaiveAlgorithm, _OptimizedAlgorithm>;
+  return std::__unwrap_and_dispatch<_Algorithm>(std::move(__first), std::move(__last), std::move(__out_first));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COPY_MOVE_COMMON_H

third_party/libcxx/__algorithm/copy_n.h

@@ -0,0 +1,67 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COPY_N_H
+#define _LIBCPP___ALGORITHM_COPY_N_H
+
+#include <__algorithm/copy.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/enable_if.h>
+#include <__utility/convert_to_integral.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _InputIterator, class _Size, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename enable_if
+<
+    __has_input_iterator_category<_InputIterator>::value &&
+   !__has_random_access_iterator_category<_InputIterator>::value,
+    _OutputIterator
+>::type
+copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
+{
+    typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
+    _IntegralSize __n = __orig_n;
+    if (__n > 0)
+    {
+        *__result = *__first;
+        ++__result;
+        for (--__n; __n > 0; --__n)
+        {
+            ++__first;
+            *__result = *__first;
+            ++__result;
+        }
+    }
+    return __result;
+}
+
+template<class _InputIterator, class _Size, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+typename enable_if
+<
+    __has_random_access_iterator_category<_InputIterator>::value,
+    _OutputIterator
+>::type
+copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
+{
+    typedef typename iterator_traits<_InputIterator>::difference_type difference_type;
+    typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
+    _IntegralSize __n = __orig_n;
+    return _VSTD::copy(__first, __first + difference_type(__n), __result);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COPY_N_H

third_party/libcxx/__algorithm/count.h

@@ -0,0 +1,35 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COUNT_H
+#define _LIBCPP___ALGORITHM_COUNT_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+    typename iterator_traits<_InputIterator>::difference_type
+    count(_InputIterator __first, _InputIterator __last, const _Tp& __value) {
+  typename iterator_traits<_InputIterator>::difference_type __r(0);
+  for (; __first != __last; ++__first)
+    if (*__first == __value)
+      ++__r;
+  return __r;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COUNT_H

third_party/libcxx/__algorithm/count_if.h

@@ -0,0 +1,35 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_COUNT_IF_H
+#define _LIBCPP___ALGORITHM_COUNT_IF_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+    typename iterator_traits<_InputIterator>::difference_type
+    count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  typename iterator_traits<_InputIterator>::difference_type __r(0);
+  for (; __first != __last; ++__first)
+    if (__pred(*__first))
+      ++__r;
+  return __r;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_COUNT_IF_H

third_party/libcxx/__algorithm/equal.h

@@ -0,0 +1,149 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_EQUAL_H
+#define _LIBCPP___ALGORITHM_EQUAL_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/unwrap_iter.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__string/constexpr_c_functions.h>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/integral_constant.h>
+#include <__type_traits/is_constant_evaluated.h>
+#include <__type_traits/is_equality_comparable.h>
+#include <__type_traits/is_volatile.h>
+#include <__type_traits/predicate_traits.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __equal_iter_impl(
+    _InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate& __pred) {
+  for (; __first1 != __last1; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      return false;
+  return true;
+}
+
+template <
+    class _Tp,
+    class _Up,
+    class _BinaryPredicate,
+    __enable_if_t<__is_trivial_equality_predicate<_BinaryPredicate, _Tp, _Up>::value && !is_volatile<_Tp>::value &&
+                      !is_volatile<_Up>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value,
+                  int> = 0>
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+__equal_iter_impl(_Tp* __first1, _Tp* __last1, _Up* __first2, _BinaryPredicate&) {
+  return std::__constexpr_memcmp_equal(__first1, __first2, (__last1 - __first1) * sizeof(_Tp));
+}
+
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred) {
+  return std::__equal_iter_impl(
+      std::__unwrap_iter(__first1), std::__unwrap_iter(__last1), std::__unwrap_iter(__first2), __pred);
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2) {
+  return std::equal(__first1, __last1, __first2, __equal_to());
+}
+
+#if _LIBCPP_STD_VER >= 14
+template <class _BinaryPredicate, class _InputIterator1, class _InputIterator2>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+__equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
+        _BinaryPredicate __pred, input_iterator_tag, input_iterator_tag) {
+  for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      return false;
+  return __first1 == __last1 && __first2 == __last2;
+}
+
+template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Pred, class _Proj1, class _Proj2>
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __equal_impl(
+    _Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2, _Pred& __comp, _Proj1& __proj1, _Proj2& __proj2) {
+  while (__first1 != __last1 && __first2 != __last2) {
+    if (!std::__invoke(__comp, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
+      return false;
+    ++__first1;
+    ++__first2;
+  }
+  return __first1 == __last1 && __first2 == __last2;
+}
+
+template <class _Tp,
+          class _Up,
+          class _Pred,
+          class _Proj1,
+          class _Proj2,
+          __enable_if_t<__is_trivial_equality_predicate<_Pred, _Tp, _Up>::value && __is_identity<_Proj1>::value &&
+                            __is_identity<_Proj2>::value && !is_volatile<_Tp>::value && !is_volatile<_Up>::value &&
+                            __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value,
+                        int> = 0>
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __equal_impl(
+    _Tp* __first1, _Tp* __last1, _Up* __first2, _Up*, _Pred&, _Proj1&, _Proj2&) {
+  return std::__constexpr_memcmp_equal(__first1, __first2, (__last1 - __first1) * sizeof(_Tp));
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+__equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2,
+        _RandomAccessIterator2 __last2, _BinaryPredicate __pred, random_access_iterator_tag,
+        random_access_iterator_tag) {
+  if (_VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
+    return false;
+  __identity __proj;
+  return std::__equal_impl(
+      std::__unwrap_iter(__first1),
+      std::__unwrap_iter(__last1),
+      std::__unwrap_iter(__first2),
+      std::__unwrap_iter(__last2),
+      __pred,
+      __proj,
+      __proj);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
+      _BinaryPredicate __pred) {
+  return _VSTD::__equal<_BinaryPredicate&>(
+      __first1, __last1, __first2, __last2, __pred, typename iterator_traits<_InputIterator1>::iterator_category(),
+      typename iterator_traits<_InputIterator2>::iterator_category());
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
+  return std::__equal(
+      __first1,
+      __last1,
+      __first2,
+      __last2,
+      __equal_to(),
+      typename iterator_traits<_InputIterator1>::iterator_category(),
+      typename iterator_traits<_InputIterator2>::iterator_category());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_EQUAL_H

third_party/libcxx/__algorithm/equal_range.h

@@ -0,0 +1,87 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_EQUAL_RANGE_H
+#define _LIBCPP___ALGORITHM_EQUAL_RANGE_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/half_positive.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/lower_bound.h>
+#include <__algorithm/upper_bound.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <__type_traits/is_callable.h>
+#include <__type_traits/is_copy_constructible.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _Compare, class _Iter, class _Sent, class _Tp, class _Proj>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_Iter, _Iter>
+__equal_range(_Iter __first, _Sent __last, const _Tp& __value, _Compare&& __comp, _Proj&& __proj) {
+  auto __len  = _IterOps<_AlgPolicy>::distance(__first, __last);
+  _Iter __end = _IterOps<_AlgPolicy>::next(__first, __last);
+  while (__len != 0) {
+    auto __half_len = std::__half_positive(__len);
+    _Iter __mid     = _IterOps<_AlgPolicy>::next(__first, __half_len);
+    if (std::__invoke(__comp, std::__invoke(__proj, *__mid), __value)) {
+      __first = ++__mid;
+      __len -= __half_len + 1;
+    } else if (std::__invoke(__comp, __value, std::__invoke(__proj, *__mid))) {
+      __end = __mid;
+      __len = __half_len;
+    } else {
+      _Iter __mp1 = __mid;
+      return pair<_Iter, _Iter>(
+          std::__lower_bound_impl<_AlgPolicy>(__first, __mid, __value, __comp, __proj),
+          std::__upper_bound<_AlgPolicy>(++__mp1, __end, __value, __comp, __proj));
+    }
+  }
+  return pair<_Iter, _Iter>(__first, __first);
+}
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
+equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp) {
+  static_assert(__is_callable<_Compare, decltype(*__first), const _Tp&>::value,
+                "The comparator has to be callable");
+  static_assert(is_copy_constructible<_ForwardIterator>::value,
+                "Iterator has to be copy constructible");
+  return std::__equal_range<_ClassicAlgPolicy>(
+      std::move(__first),
+      std::move(__last),
+      __value,
+      static_cast<__comp_ref_type<_Compare> >(__comp),
+      std::__identity());
+}
+
+template <class _ForwardIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
+equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
+  return std::equal_range(
+      std::move(__first),
+      std::move(__last),
+      __value,
+      __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_EQUAL_RANGE_H

third_party/libcxx/__algorithm/fill.h

@@ -0,0 +1,51 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FILL_H
+#define _LIBCPP___ALGORITHM_FILL_H
+
+#include <__algorithm/fill_n.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// fill isn't specialized for std::memset, because the compiler already optimizes the loop to a call to std::memset.
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+__fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, forward_iterator_tag)
+{
+    for (; __first != __last; ++__first)
+        *__first = __value;
+}
+
+template <class _RandomAccessIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+__fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value, random_access_iterator_tag)
+{
+    _VSTD::fill_n(__first, __last - __first, __value);
+}
+
+template <class _ForwardIterator, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value)
+{
+    _VSTD::__fill(__first, __last, __value, typename iterator_traits<_ForwardIterator>::iterator_category());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FILL_H

third_party/libcxx/__algorithm/fill_n.h

@@ -0,0 +1,44 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FILL_N_H
+#define _LIBCPP___ALGORITHM_FILL_N_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/convert_to_integral.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// fill_n isn't specialized for std::memset, because the compiler already optimizes the loop to a call to std::memset.
+
+template <class _OutputIterator, class _Size, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+_OutputIterator
+__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value)
+{
+    for (; __n > 0; ++__first, (void) --__n)
+        *__first = __value;
+    return __first;
+}
+
+template <class _OutputIterator, class _Size, class _Tp>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+_OutputIterator
+fill_n(_OutputIterator __first, _Size __n, const _Tp& __value)
+{
+   return _VSTD::__fill_n(__first, _VSTD::__convert_to_integral(__n), __value);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FILL_N_H

third_party/libcxx/__algorithm/find.h

@@ -0,0 +1,77 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_H
+#define _LIBCPP___ALGORITHM_FIND_H
+
+#include <__algorithm/unwrap_iter.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__string/constexpr_c_functions.h>
+#include <__type_traits/is_same.h>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#  include <cwchar>
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Iter, class _Sent, class _Tp, class _Proj>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iter
+__find_impl(_Iter __first, _Sent __last, const _Tp& __value, _Proj& __proj) {
+  for (; __first != __last; ++__first)
+    if (std::__invoke(__proj, *__first) == __value)
+      break;
+  return __first;
+}
+
+template <class _Tp,
+          class _Up,
+          class _Proj,
+          __enable_if_t<__is_identity<_Proj>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&
+                            sizeof(_Tp) == 1,
+                        int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp*
+__find_impl(_Tp* __first, _Tp* __last, const _Up& __value, _Proj&) {
+  if (auto __ret = std::__constexpr_memchr(__first, __value, __last - __first))
+    return __ret;
+  return __last;
+}
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+template <class _Tp,
+          class _Up,
+          class _Proj,
+          __enable_if_t<__is_identity<_Proj>::value && __libcpp_is_trivially_equality_comparable<_Tp, _Up>::value &&
+                            sizeof(_Tp) == sizeof(wchar_t) && _LIBCPP_ALIGNOF(_Tp) >= _LIBCPP_ALIGNOF(wchar_t),
+                        int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Tp*
+__find_impl(_Tp* __first, _Tp* __last, const _Up& __value, _Proj&) {
+  if (auto __ret = std::__constexpr_wmemchr(__first, __value, __last - __first))
+    return __ret;
+  return __last;
+}
+#endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
+
+template <class _InputIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
+find(_InputIterator __first, _InputIterator __last, const _Tp& __value) {
+  __identity __proj;
+  return std::__rewrap_iter(
+      __first, std::__find_impl(std::__unwrap_iter(__first), std::__unwrap_iter(__last), __value, __proj));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FIND_H

third_party/libcxx/__algorithm/find_end.h

@@ -0,0 +1,227 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_END_OF_H
+#define _LIBCPP___ALGORITHM_FIND_END_OF_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/search.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/advance.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <__iterator/reverse_iterator.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <
+    class _AlgPolicy,
+    class _Iter1,
+    class _Sent1,
+    class _Iter2,
+    class _Sent2,
+    class _Pred,
+    class _Proj1,
+    class _Proj2>
+_LIBCPP_HIDE_FROM_ABI inline _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter1, _Iter1> __find_end_impl(
+    _Iter1 __first1,
+    _Sent1 __last1,
+    _Iter2 __first2,
+    _Sent2 __last2,
+    _Pred& __pred,
+    _Proj1& __proj1,
+    _Proj2& __proj2,
+    forward_iterator_tag,
+    forward_iterator_tag) {
+  // modeled after search algorithm
+  _Iter1 __match_first = _IterOps<_AlgPolicy>::next(__first1, __last1); // __last1 is the "default" answer
+  _Iter1 __match_last = __match_first;
+  if (__first2 == __last2)
+    return pair<_Iter1, _Iter1>(__match_last, __match_last);
+  while (true) {
+    while (true) {
+      if (__first1 == __last1) // if source exhausted return last correct answer (or __last1 if never found)
+        return pair<_Iter1, _Iter1>(__match_first, __match_last);
+      if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
+        break;
+      ++__first1;
+    }
+    // *__first1 matches *__first2, now match elements after here
+    _Iter1 __m1 = __first1;
+    _Iter2 __m2 = __first2;
+    while (true) {
+      if (++__m2 == __last2) { // Pattern exhaused, record answer and search for another one
+        __match_first = __first1;
+        __match_last = ++__m1;
+        ++__first1;
+        break;
+      }
+      if (++__m1 == __last1) // Source exhausted, return last answer
+        return pair<_Iter1, _Iter1>(__match_first, __match_last);
+       // mismatch, restart with a new __first
+      if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2)))
+      {
+        ++__first1;
+        break;
+      } // else there is a match, check next elements
+    }
+  }
+}
+
+template <
+    class _IterOps,
+    class _Pred,
+    class _Iter1,
+    class _Sent1,
+    class _Iter2,
+    class _Sent2,
+    class _Proj1,
+    class _Proj2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter1 __find_end(
+    _Iter1 __first1,
+    _Sent1 __sent1,
+    _Iter2 __first2,
+    _Sent2 __sent2,
+    _Pred& __pred,
+    _Proj1& __proj1,
+    _Proj2& __proj2,
+    bidirectional_iterator_tag,
+    bidirectional_iterator_tag) {
+  auto __last1 = _IterOps::next(__first1, __sent1);
+  auto __last2 = _IterOps::next(__first2, __sent2);
+  // modeled after search algorithm (in reverse)
+  if (__first2 == __last2)
+    return __last1; // Everything matches an empty sequence
+  _Iter1 __l1 = __last1;
+  _Iter2 __l2 = __last2;
+  --__l2;
+  while (true) {
+    // Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks
+    while (true) {
+      if (__first1 == __l1) // return __last1 if no element matches *__first2
+        return __last1;
+      if (std::__invoke(__pred, std::__invoke(__proj1, *--__l1), std::__invoke(__proj2, *__l2)))
+        break;
+    }
+    // *__l1 matches *__l2, now match elements before here
+    _Iter1 __m1 = __l1;
+    _Iter2 __m2 = __l2;
+    while (true) {
+      if (__m2 == __first2) // If pattern exhausted, __m1 is the answer (works for 1 element pattern)
+        return __m1;
+      if (__m1 == __first1) // Otherwise if source exhaused, pattern not found
+        return __last1;
+
+      // if there is a mismatch, restart with a new __l1
+      if (!std::__invoke(__pred, std::__invoke(__proj1, *--__m1), std::__invoke(__proj2, *--__m2)))
+      {
+        break;
+      } // else there is a match, check next elements
+    }
+  }
+}
+
+template <
+    class _AlgPolicy,
+    class _Pred,
+    class _Iter1,
+    class _Sent1,
+    class _Iter2,
+    class _Sent2,
+    class _Proj1,
+    class _Proj2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iter1 __find_end(
+    _Iter1 __first1,
+    _Sent1 __sent1,
+    _Iter2 __first2,
+    _Sent2 __sent2,
+    _Pred& __pred,
+    _Proj1& __proj1,
+    _Proj2& __proj2,
+    random_access_iterator_tag,
+    random_access_iterator_tag) {
+  typedef typename iterator_traits<_Iter1>::difference_type _D1;
+  auto __last1 = _IterOps<_AlgPolicy>::next(__first1, __sent1);
+  auto __last2 = _IterOps<_AlgPolicy>::next(__first2, __sent2);
+  // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
+  auto __len2 = __last2 - __first2;
+  if (__len2 == 0)
+    return __last1;
+  auto __len1 = __last1 - __first1;
+  if (__len1 < __len2)
+    return __last1;
+  const _Iter1 __s = __first1 + _D1(__len2 - 1); // End of pattern match can't go before here
+  _Iter1 __l1 = __last1;
+  _Iter2 __l2 = __last2;
+  --__l2;
+  while (true) {
+    while (true) {
+      if (__s == __l1)
+        return __last1;
+      if (std::__invoke(__pred, std::__invoke(__proj1, *--__l1), std::__invoke(__proj2, *__l2)))
+        break;
+    }
+    _Iter1 __m1 = __l1;
+    _Iter2 __m2 = __l2;
+    while (true) {
+      if (__m2 == __first2)
+        return __m1;
+      // no need to check range on __m1 because __s guarantees we have enough source
+      if (!std::__invoke(__pred, std::__invoke(__proj1, *--__m1), std::__invoke(*--__m2))) {
+        break;
+      }
+    }
+  }
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+_ForwardIterator1 __find_end_classic(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                                     _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+                                     _BinaryPredicate& __pred) {
+  auto __proj = __identity();
+  return std::__find_end_impl<_ClassicAlgPolicy>(
+             __first1,
+             __last1,
+             __first2,
+             __last2,
+             __pred,
+             __proj,
+             __proj,
+             typename iterator_traits<_ForwardIterator1>::iterator_category(),
+             typename iterator_traits<_ForwardIterator2>::iterator_category())
+      .first;
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+_ForwardIterator1 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                           _ForwardIterator2 __first2, _ForwardIterator2 __last2,
+                           _BinaryPredicate __pred) {
+  return std::__find_end_classic(__first1, __last1, __first2, __last2, __pred);
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+_ForwardIterator1 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
+                           _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
+  return std::find_end(__first1, __last1, __first2, __last2, __equal_to());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FIND_END_OF_H

third_party/libcxx/__algorithm/find_first_of.h

@@ -0,0 +1,52 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_FIRST_OF_H
+#define _LIBCPP___ALGORITHM_FIND_FIRST_OF_H
+
+#include <__algorithm/comp.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_HIDE_FROM_ABI
+_LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator1 __find_first_of_ce(_ForwardIterator1 __first1,
+                                                                   _ForwardIterator1 __last1,
+                                                                   _ForwardIterator2 __first2,
+                                                                   _ForwardIterator2 __last2,
+                                                                   _BinaryPredicate&& __pred) {
+  for (; __first1 != __last1; ++__first1)
+    for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
+      if (__pred(*__first1, *__j))
+        return __first1;
+  return __last1;
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1
+find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+              _ForwardIterator2 __last2, _BinaryPredicate __pred) {
+  return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __pred);
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 find_first_of(
+    _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
+  return std::__find_first_of_ce(__first1, __last1, __first2, __last2, __equal_to());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FIND_FIRST_OF_H

third_party/libcxx/__algorithm/find_if.h

@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_IF_H
+#define _LIBCPP___ALGORITHM_FIND_IF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
+find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  for (; __first != __last; ++__first)
+    if (__pred(*__first))
+      break;
+  return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FIND_IF_H

third_party/libcxx/__algorithm/find_if_not.h

@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FIND_IF_NOT_H
+#define _LIBCPP___ALGORITHM_FIND_IF_NOT_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator
+find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  for (; __first != __last; ++__first)
+    if (!__pred(*__first))
+      break;
+  return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FIND_IF_NOT_H

third_party/libcxx/__algorithm/for_each.h

@@ -0,0 +1,47 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FOR_EACH_H
+#define _LIBCPP___ALGORITHM_FOR_EACH_H
+
+#include <__algorithm/for_each_segment.h>
+#include <__config>
+#include <__iterator/segmented_iterator.h>
+#include <__type_traits/enable_if.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Function>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Function
+for_each(_InputIterator __first, _InputIterator __last, _Function __f) {
+  for (; __first != __last; ++__first)
+    __f(*__first);
+  return __f;
+}
+
+#if _LIBCPP_STD_VER >= 20
+template <class _SegmentedIterator, class _Function>
+  requires __is_segmented_iterator<_SegmentedIterator>::value
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Function
+for_each(_SegmentedIterator __first, _SegmentedIterator __last, _Function __func) {
+  std::__for_each_segment(__first, __last, [&](auto __lfirst, auto __llast) {
+    __func = std::for_each(__lfirst, __llast, std::move(__func));
+  });
+  return __func;
+}
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FOR_EACH_H

third_party/libcxx/__algorithm/for_each_n.h

@@ -0,0 +1,42 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FOR_EACH_N_H
+#define _LIBCPP___ALGORITHM_FOR_EACH_N_H
+
+#include <__config>
+#include <__utility/convert_to_integral.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 17
+
+template <class _InputIterator, class _Size, class _Function>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _InputIterator for_each_n(_InputIterator __first,
+                                                                                         _Size __orig_n,
+                                                                                         _Function __f) {
+  typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
+  _IntegralSize __n = __orig_n;
+  while (__n > 0) {
+    __f(*__first);
+    ++__first;
+    --__n;
+  }
+  return __first;
+}
+
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FOR_EACH_N_H

third_party/libcxx/__algorithm/for_each_segment.h

@@ -0,0 +1,53 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_FOR_EACH_SEGMENT_H
+#define _LIBCPP___ALGORITHM_FOR_EACH_SEGMENT_H
+
+#include <__config>
+#include <__iterator/segmented_iterator.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// __for_each_segment is a utility function for optimizing iterating over segmented iterators linearly.
+// __first and __last are expected to be a segmented range. __func is expected to take a range of local iterators.
+// Anything that is returned from __func is ignored.
+
+template <class _SegmentedIterator, class _Functor>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
+__for_each_segment(_SegmentedIterator __first, _SegmentedIterator __last, _Functor __func) {
+  using _Traits = __segmented_iterator_traits<_SegmentedIterator>;
+
+  auto __sfirst = _Traits::__segment(__first);
+  auto __slast  = _Traits::__segment(__last);
+
+  // We are in a single segment, so we might not be at the beginning or end
+  if (__sfirst == __slast) {
+    __func(_Traits::__local(__first), _Traits::__local(__last));
+    return;
+  }
+
+  // We have more than one segment. Iterate over the first segment, since we might not start at the beginning
+  __func(_Traits::__local(__first), _Traits::__end(__sfirst));
+  ++__sfirst;
+  // iterate over the segments which are guaranteed to be completely in the range
+  while (__sfirst != __slast) {
+    __func(_Traits::__begin(__sfirst), _Traits::__end(__sfirst));
+    ++__sfirst;
+  }
+  // iterate over the last segment
+  __func(_Traits::__begin(__sfirst), _Traits::__local(__last));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_FOR_EACH_SEGMENT_H

third_party/libcxx/__algorithm/generate.h

@@ -0,0 +1,31 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_GENERATE_H
+#define _LIBCPP___ALGORITHM_GENERATE_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Generator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen)
+{
+    for (; __first != __last; ++__first)
+        *__first = __gen();
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_GENERATE_H

third_party/libcxx/__algorithm/generate_n.h

@@ -0,0 +1,35 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_GENERATE_N_H
+#define _LIBCPP___ALGORITHM_GENERATE_N_H
+
+#include <__config>
+#include <__utility/convert_to_integral.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _OutputIterator, class _Size, class _Generator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+_OutputIterator
+generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen)
+{
+    typedef decltype(_VSTD::__convert_to_integral(__orig_n)) _IntegralSize;
+    _IntegralSize __n = __orig_n;
+    for (; __n > 0; ++__first, (void) --__n)
+        *__first = __gen();
+    return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_GENERATE_N_H

third_party/libcxx/__algorithm/half_positive.h

@@ -0,0 +1,51 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_HALF_POSITIVE_H
+#define _LIBCPP___ALGORITHM_HALF_POSITIVE_H
+
+#include <__config>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_integral.h>
+#include <__type_traits/make_unsigned.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// Perform division by two quickly for positive integers (llvm.org/PR39129)
+
+template <typename _Integral>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    is_integral<_Integral>::value,
+    _Integral
+>::type
+__half_positive(_Integral __value)
+{
+    return static_cast<_Integral>(static_cast<__make_unsigned_t<_Integral> >(__value) / 2);
+}
+
+template <typename _Tp>
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
+typename enable_if
+<
+    !is_integral<_Tp>::value,
+    _Tp
+>::type
+__half_positive(_Tp __value)
+{
+    return __value / 2;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_HALF_POSITIVE_H

third_party/libcxx/__algorithm/in_found_result.h

@@ -0,0 +1,49 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IN_FOUND_RESULT_H
+#define _LIBCPP___ALGORITHM_IN_FOUND_RESULT_H
+
+#include <__concepts/convertible_to.h>
+#include <__config>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+template <class _InIter1>
+struct in_found_result {
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in;
+  bool found;
+
+  template <class _InIter2>
+    requires convertible_to<const _InIter1&, _InIter2>
+  _LIBCPP_HIDE_FROM_ABI constexpr operator in_found_result<_InIter2>() const & {
+    return {in, found};
+  }
+
+  template <class _InIter2>
+    requires convertible_to<_InIter1, _InIter2>
+  _LIBCPP_HIDE_FROM_ABI constexpr operator in_found_result<_InIter2>() && {
+    return {std::move(in), found};
+  }
+};
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#endif // _LIBCPP___ALGORITHM_IN_FOUND_RESULT_H

third_party/libcxx/__algorithm/in_fun_result.h

@@ -0,0 +1,49 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IN_FUN_RESULT_H
+#define _LIBCPP___ALGORITHM_IN_FUN_RESULT_H
+
+#include <__concepts/convertible_to.h>
+#include <__config>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+namespace ranges {
+template <class _InIter1, class _Func1>
+struct in_fun_result {
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in;
+  _LIBCPP_NO_UNIQUE_ADDRESS _Func1 fun;
+
+  template <class _InIter2, class _Func2>
+    requires convertible_to<const _InIter1&, _InIter2> && convertible_to<const _Func1&, _Func2>
+  _LIBCPP_HIDE_FROM_ABI constexpr operator in_fun_result<_InIter2, _Func2>() const & {
+    return {in, fun};
+  }
+
+  template <class _InIter2, class _Func2>
+    requires convertible_to<_InIter1, _InIter2> && convertible_to<_Func1, _Func2>
+  _LIBCPP_HIDE_FROM_ABI constexpr operator in_fun_result<_InIter2, _Func2>() && {
+    return {std::move(in), std::move(fun)};
+  }
+};
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IN_FUN_RESULT_H

third_party/libcxx/__algorithm/in_in_out_result.h

@@ -0,0 +1,56 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IN_IN_OUT_RESULT_H
+#define _LIBCPP___ALGORITHM_IN_IN_OUT_RESULT_H
+
+#include <__concepts/convertible_to.h>
+#include <__config>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+namespace ranges {
+
+template <class _InIter1, class _InIter2, class _OutIter1>
+struct in_in_out_result {
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in1;
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter2 in2;
+  _LIBCPP_NO_UNIQUE_ADDRESS _OutIter1 out;
+
+  template <class _InIter3, class _InIter4, class _OutIter2>
+    requires convertible_to<const _InIter1&, _InIter3>
+          && convertible_to<const _InIter2&, _InIter4> && convertible_to<const _OutIter1&, _OutIter2>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  operator in_in_out_result<_InIter3, _InIter4, _OutIter2>() const& {
+    return {in1, in2, out};
+  }
+
+  template <class _InIter3, class _InIter4, class _OutIter2>
+    requires convertible_to<_InIter1, _InIter3>
+          && convertible_to<_InIter2, _InIter4> && convertible_to<_OutIter1, _OutIter2>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  operator in_in_out_result<_InIter3, _InIter4, _OutIter2>() && {
+    return {std::move(in1), std::move(in2), std::move(out)};
+  }
+};
+
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IN_IN_OUT_RESULT_H

third_party/libcxx/__algorithm/in_in_result.h

@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IN_IN_RESULT_H
+#define _LIBCPP___ALGORITHM_IN_IN_RESULT_H
+
+#include <__concepts/convertible_to.h>
+#include <__config>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+namespace ranges {
+
+template <class _InIter1, class _InIter2>
+struct in_in_result {
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in1;
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter2 in2;
+
+  template <class _InIter3, class _InIter4>
+    requires convertible_to<const _InIter1&, _InIter3> && convertible_to<const _InIter2&, _InIter4>
+   _LIBCPP_HIDE_FROM_ABI constexpr
+   operator in_in_result<_InIter3, _InIter4>() const & {
+    return {in1, in2};
+  }
+
+  template <class _InIter3, class _InIter4>
+    requires convertible_to<_InIter1, _InIter3> && convertible_to<_InIter2, _InIter4>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  operator in_in_result<_InIter3, _InIter4>() && {
+    return {std::move(in1), std::move(in2)};
+  }
+};
+
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IN_IN_RESULT_H

third_party/libcxx/__algorithm/in_out_out_result.h

@@ -0,0 +1,54 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IN_OUT_OUT_RESULT_H
+#define _LIBCPP___ALGORITHM_IN_OUT_OUT_RESULT_H
+
+#include <__concepts/convertible_to.h>
+#include <__config>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+namespace ranges {
+template <class _InIter1, class _OutIter1, class _OutIter2>
+struct in_out_out_result {
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in;
+  _LIBCPP_NO_UNIQUE_ADDRESS _OutIter1 out1;
+  _LIBCPP_NO_UNIQUE_ADDRESS _OutIter2 out2;
+
+  template <class _InIter2, class _OutIter3, class _OutIter4>
+    requires convertible_to<const _InIter1&, _InIter2>
+          && convertible_to<const _OutIter1&, _OutIter3> && convertible_to<const _OutIter2&, _OutIter4>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  operator in_out_out_result<_InIter2, _OutIter3, _OutIter4>() const& {
+    return {in, out1, out2};
+  }
+
+  template <class _InIter2, class _OutIter3, class _OutIter4>
+    requires convertible_to<_InIter1, _InIter2>
+          && convertible_to<_OutIter1, _OutIter3> && convertible_to<_OutIter2, _OutIter4>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  operator in_out_out_result<_InIter2, _OutIter3, _OutIter4>() && {
+    return {std::move(in), std::move(out1), std::move(out2)};
+  }
+};
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IN_OUT_OUT_RESULT_H

third_party/libcxx/__algorithm/in_out_result.h

@@ -0,0 +1,53 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IN_OUT_RESULT_H
+#define _LIBCPP___ALGORITHM_IN_OUT_RESULT_H
+
+#include <__concepts/convertible_to.h>
+#include <__config>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+namespace ranges {
+
+template<class _InIter1, class _OutIter1>
+struct in_out_result {
+  _LIBCPP_NO_UNIQUE_ADDRESS _InIter1 in;
+  _LIBCPP_NO_UNIQUE_ADDRESS _OutIter1 out;
+
+  template <class _InIter2, class _OutIter2>
+    requires convertible_to<const _InIter1&, _InIter2> && convertible_to<const _OutIter1&, _OutIter2>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr operator in_out_result<_InIter2, _OutIter2>() const & {
+    return {in, out};
+  }
+
+  template <class _InIter2, class _OutIter2>
+    requires convertible_to<_InIter1, _InIter2> && convertible_to<_OutIter1, _OutIter2>
+  _LIBCPP_HIDE_FROM_ABI
+  constexpr operator in_out_result<_InIter2, _OutIter2>() && {
+    return {std::move(in), std::move(out)};
+  }
+};
+
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IN_OUT_RESULT_H

third_party/libcxx/__algorithm/includes.h

@@ -0,0 +1,75 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_INCLUDES_H
+#define _LIBCPP___ALGORITHM_INCLUDES_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_callable.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class _Comp, class _Proj1, class _Proj2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+__includes(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
+           _Comp&& __comp, _Proj1&& __proj1, _Proj2&& __proj2) {
+  for (; __first2 != __last2; ++__first1) {
+    if (__first1 == __last1 || std::__invoke(
+          __comp, std::__invoke(__proj2, *__first2), std::__invoke(__proj1, *__first1)))
+      return false;
+    if (!std::__invoke(__comp, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
+      ++__first2;
+  }
+  return true;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Compare>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool includes(
+    _InputIterator1 __first1,
+    _InputIterator1 __last1,
+    _InputIterator2 __first2,
+    _InputIterator2 __last2,
+    _Compare __comp) {
+  static_assert(__is_callable<_Compare, decltype(*__first1), decltype(*__first2)>::value,
+      "Comparator has to be callable");
+
+  return std::__includes(
+      std::move(__first1),
+      std::move(__last1),
+      std::move(__first2),
+      std::move(__last2),
+      static_cast<__comp_ref_type<_Compare> >(__comp),
+      __identity(),
+      __identity());
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
+  return std::includes(
+      std::move(__first1),
+      std::move(__last1),
+      std::move(__first2),
+      std::move(__last2),
+      __less<typename iterator_traits<_InputIterator1>::value_type,
+             typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_INCLUDES_H

third_party/libcxx/__algorithm/inplace_merge.h

@@ -0,0 +1,257 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_INPLACE_MERGE_H
+#define _LIBCPP___ALGORITHM_INPLACE_MERGE_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/lower_bound.h>
+#include <__algorithm/min.h>
+#include <__algorithm/move.h>
+#include <__algorithm/rotate.h>
+#include <__algorithm/upper_bound.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/reverse_iterator.h>
+#include <__memory/destruct_n.h>
+#include <__memory/temporary_buffer.h>
+#include <__memory/unique_ptr.h>
+#include <__utility/pair.h>
+#include <new>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Predicate>
+class __invert // invert the sense of a comparison
+{
+private:
+    _Predicate __p_;
+public:
+    _LIBCPP_INLINE_VISIBILITY __invert() {}
+
+    _LIBCPP_INLINE_VISIBILITY
+    explicit __invert(_Predicate __p) : __p_(__p) {}
+
+    template <class _T1>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _T1& __x) {return !__p_(__x);}
+
+    template <class _T1, class _T2>
+    _LIBCPP_INLINE_VISIBILITY
+    bool operator()(const _T1& __x, const _T2& __y) {return __p_(__y, __x);}
+};
+
+template <class _AlgPolicy, class _Compare, class _InputIterator1, class _Sent1,
+          class _InputIterator2, class _Sent2, class _OutputIterator>
+_LIBCPP_HIDE_FROM_ABI
+void __half_inplace_merge(_InputIterator1 __first1, _Sent1 __last1,
+                          _InputIterator2 __first2, _Sent2 __last2,
+                          _OutputIterator __result, _Compare&& __comp)
+{
+    for (; __first1 != __last1; ++__result)
+    {
+        if (__first2 == __last2)
+        {
+            std::__move<_AlgPolicy>(__first1, __last1, __result);
+            return;
+        }
+
+        if (__comp(*__first2, *__first1))
+        {
+            *__result = _IterOps<_AlgPolicy>::__iter_move(__first2);
+            ++__first2;
+        }
+        else
+        {
+            *__result = _IterOps<_AlgPolicy>::__iter_move(__first1);
+            ++__first1;
+        }
+    }
+    // __first2 through __last2 are already in the right spot.
+}
+
+template <class _AlgPolicy, class _Compare, class _BidirectionalIterator>
+_LIBCPP_HIDE_FROM_ABI
+void __buffered_inplace_merge(
+    _BidirectionalIterator __first,
+    _BidirectionalIterator __middle,
+    _BidirectionalIterator __last,
+    _Compare&& __comp,
+    typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
+    typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
+    typename iterator_traits<_BidirectionalIterator>::value_type* __buff) {
+  typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    __destruct_n __d(0);
+    unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
+    if (__len1 <= __len2)
+    {
+        value_type* __p = __buff;
+        for (_BidirectionalIterator __i = __first; __i != __middle; __d.template __incr<value_type>(), (void) ++__i, (void) ++__p)
+            ::new ((void*)__p) value_type(_IterOps<_AlgPolicy>::__iter_move(__i));
+        std::__half_inplace_merge<_AlgPolicy>(__buff, __p, __middle, __last, __first, __comp);
+    }
+    else
+    {
+        value_type* __p = __buff;
+        for (_BidirectionalIterator __i = __middle; __i != __last; __d.template __incr<value_type>(), (void) ++__i, (void) ++__p)
+            ::new ((void*)__p) value_type(_IterOps<_AlgPolicy>::__iter_move(__i));
+        typedef __unconstrained_reverse_iterator<_BidirectionalIterator> _RBi;
+        typedef __unconstrained_reverse_iterator<value_type*> _Rv;
+        typedef __invert<_Compare> _Inverted;
+        std::__half_inplace_merge<_AlgPolicy>(_Rv(__p), _Rv(__buff),
+                                    _RBi(__middle), _RBi(__first),
+                                    _RBi(__last), _Inverted(__comp));
+    }
+}
+
+template <class _AlgPolicy, class _Compare, class _BidirectionalIterator>
+void __inplace_merge(
+    _BidirectionalIterator __first,
+    _BidirectionalIterator __middle,
+    _BidirectionalIterator __last,
+    _Compare&& __comp,
+    typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
+    typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
+    typename iterator_traits<_BidirectionalIterator>::value_type* __buff,
+    ptrdiff_t __buff_size) {
+    using _Ops = _IterOps<_AlgPolicy>;
+
+    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
+    while (true)
+    {
+        // if __middle == __last, we're done
+        if (__len2 == 0)
+            return;
+        if (__len1 <= __buff_size || __len2 <= __buff_size)
+            return std::__buffered_inplace_merge<_AlgPolicy>
+                   (__first, __middle, __last, __comp, __len1, __len2, __buff);
+        // shrink [__first, __middle) as much as possible (with no moves), returning if it shrinks to 0
+        for (; true; ++__first, (void) --__len1)
+        {
+            if (__len1 == 0)
+                return;
+            if (__comp(*__middle, *__first))
+                break;
+        }
+        // __first < __middle < __last
+        // *__first > *__middle
+        // partition [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) such that
+        //     all elements in:
+        //         [__first, __m1)  <= [__middle, __m2)
+        //         [__middle, __m2) <  [__m1, __middle)
+        //         [__m1, __middle) <= [__m2, __last)
+        //     and __m1 or __m2 is in the middle of its range
+        _BidirectionalIterator __m1;  // "median" of [__first, __middle)
+        _BidirectionalIterator __m2;  // "median" of [__middle, __last)
+        difference_type __len11;      // distance(__first, __m1)
+        difference_type __len21;      // distance(__middle, __m2)
+        // binary search smaller range
+        if (__len1 < __len2)
+        {   // __len >= 1, __len2 >= 2
+            __len21 = __len2 / 2;
+            __m2 = __middle;
+            _Ops::advance(__m2, __len21);
+            __m1 = std::__upper_bound<_AlgPolicy>(__first, __middle, *__m2, __comp, std::__identity());
+            __len11 = _Ops::distance(__first, __m1);
+        }
+        else
+        {
+            if (__len1 == 1)
+            {   // __len1 >= __len2 && __len2 > 0, therefore __len2 == 1
+                // It is known *__first > *__middle
+              _Ops::iter_swap(__first, __middle);
+                return;
+            }
+            // __len1 >= 2, __len2 >= 1
+            __len11 = __len1 / 2;
+            __m1 = __first;
+            _Ops::advance(__m1, __len11);
+            __m2 = std::lower_bound(__middle, __last, *__m1, __comp);
+            __len21 = _Ops::distance(__middle, __m2);
+        }
+        difference_type __len12 = __len1 - __len11;  // distance(__m1, __middle)
+        difference_type __len22 = __len2 - __len21;  // distance(__m2, __last)
+        // [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last)
+        // swap middle two partitions
+        __middle = std::__rotate<_AlgPolicy>(__m1, __middle, __m2).first;
+        // __len12 and __len21 now have swapped meanings
+        // merge smaller range with recursive call and larger with tail recursion elimination
+        if (__len11 + __len21 < __len12 + __len22)
+        {
+            std::__inplace_merge<_AlgPolicy>(
+                __first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
+            __first = __middle;
+            __middle = __m2;
+            __len1 = __len12;
+            __len2 = __len22;
+        }
+        else
+        {
+            std::__inplace_merge<_AlgPolicy>(
+                __middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
+            __last = __middle;
+            __middle = __m1;
+            __len1 = __len11;
+            __len2 = __len21;
+        }
+    }
+}
+
+template <class _AlgPolicy, class _BidirectionalIterator, class _Compare>
+_LIBCPP_HIDE_FROM_ABI
+void
+__inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
+              _Compare&& __comp)
+{
+    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
+    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
+    difference_type __len1 = _IterOps<_AlgPolicy>::distance(__first, __middle);
+    difference_type __len2 = _IterOps<_AlgPolicy>::distance(__middle, __last);
+    difference_type __buf_size = _VSTD::min(__len1, __len2);
+// TODO: Remove the use of std::get_temporary_buffer
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+    pair<value_type*, ptrdiff_t> __buf = _VSTD::get_temporary_buffer<value_type>(__buf_size);
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+    unique_ptr<value_type, __return_temporary_buffer> __h(__buf.first);
+    return std::__inplace_merge<_AlgPolicy>(
+        std::move(__first), std::move(__middle), std::move(__last), __comp, __len1, __len2, __buf.first, __buf.second);
+}
+
+template <class _BidirectionalIterator, class _Compare>
+inline _LIBCPP_HIDE_FROM_ABI void inplace_merge(
+    _BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last, _Compare __comp) {
+  std::__inplace_merge<_ClassicAlgPolicy>(
+      std::move(__first), std::move(__middle), std::move(__last), static_cast<__comp_ref_type<_Compare> >(__comp));
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_HIDE_FROM_ABI
+void
+inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last)
+{
+    std::inplace_merge(std::move(__first), std::move(__middle), std::move(__last),
+                        __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_INPLACE_MERGE_H

third_party/libcxx/__algorithm/is_heap.h

@@ -0,0 +1,44 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_HEAP_H
+#define _LIBCPP___ALGORITHM_IS_HEAP_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/is_heap_until.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _RandomAccessIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    return std::__is_heap_until(__first, __last, static_cast<__comp_ref_type<_Compare> >(__comp)) == __last;
+}
+
+template<class _RandomAccessIterator>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    return _VSTD::is_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_HEAP_H

third_party/libcxx/__algorithm/is_heap_until.h

@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H
+#define _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _RandomAccessIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
+__is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp)
+{
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    difference_type __len = __last - __first;
+    difference_type __p = 0;
+    difference_type __c = 1;
+    _RandomAccessIterator __pp = __first;
+    while (__c < __len)
+    {
+        _RandomAccessIterator __cp = __first + __c;
+        if (__comp(*__pp, *__cp))
+            return __cp;
+        ++__c;
+        ++__cp;
+        if (__c == __len)
+            return __last;
+        if (__comp(*__pp, *__cp))
+            return __cp;
+        ++__p;
+        ++__pp;
+        __c = 2 * __p + 1;
+    }
+    return __last;
+}
+
+template <class _RandomAccessIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
+is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
+{
+    return std::__is_heap_until(__first, __last, static_cast<__comp_ref_type<_Compare> >(__comp));
+}
+
+template<class _RandomAccessIterator>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
+is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
+{
+    return _VSTD::__is_heap_until(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H

third_party/libcxx/__algorithm/is_partitioned.h

@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_PARTITIONED_H
+#define _LIBCPP___ALGORITHM_IS_PARTITIONED_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+is_partitioned(_InputIterator __first, _InputIterator __last, _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+        if (!__pred(*__first))
+            break;
+    if ( __first == __last )
+        return true;
+    ++__first;
+    for (; __first != __last; ++__first)
+        if (__pred(*__first))
+            return false;
+    return true;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_PARTITIONED_H

third_party/libcxx/__algorithm/is_permutation.h

@@ -0,0 +1,238 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_PERMUTATION_H
+#define _LIBCPP___ALGORITHM_IS_PERMUTATION_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/iterator_operations.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/concepts.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <__type_traits/is_callable.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class = void>
+struct _ConstTimeDistance : false_type {};
+
+#if _LIBCPP_STD_VER >= 20
+
+template <class _Iter1, class _Sent1, class _Iter2, class _Sent2>
+struct _ConstTimeDistance<_Iter1, _Sent1, _Iter2, _Sent2, __enable_if_t<
+  sized_sentinel_for<_Sent1, _Iter1> &&
+  sized_sentinel_for<_Sent2, _Iter2>
+>> : true_type {};
+
+#else
+
+template <class _Iter1, class _Iter2>
+struct _ConstTimeDistance<_Iter1, _Iter1, _Iter2, _Iter2, __enable_if_t<
+    is_same<typename iterator_traits<_Iter1>::iterator_category, random_access_iterator_tag>::value &&
+    is_same<typename iterator_traits<_Iter2>::iterator_category, random_access_iterator_tag>::value
+> > : true_type {};
+
+#endif // _LIBCPP_STD_VER >= 20
+
+// Internal functions
+
+// For each element in [f1, l1) see if there are the same number of equal elements in [f2, l2)
+template <class _AlgPolicy,
+          class _Iter1, class _Sent1, class _Iter2, class _Sent2,
+          class _Proj1, class _Proj2, class _Pred>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+__is_permutation_impl(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
+                      _Pred&& __pred, _Proj1&& __proj1, _Proj2&& __proj2) {
+  using _D1 = __iter_diff_t<_Iter1>;
+
+  for (auto __i = __first1; __i != __last1; ++__i) {
+    //  Have we already counted the number of *__i in [f1, l1)?
+    auto __match = __first1;
+    for (; __match != __i; ++__match) {
+      if (std::__invoke(__pred, std::__invoke(__proj1, *__match), std::__invoke(__proj1, *__i)))
+        break;
+    }
+
+    if (__match == __i) {
+      // Count number of *__i in [f2, l2)
+      _D1 __c2 = 0;
+      for (auto __j = __first2; __j != __last2; ++__j) {
+        if (std::__invoke(__pred, std::__invoke(__proj1, *__i), std::__invoke(__proj2, *__j)))
+          ++__c2;
+      }
+      if (__c2 == 0)
+        return false;
+
+      // Count number of *__i in [__i, l1) (we can start with 1)
+      _D1 __c1 = 1;
+      for (auto __j = _IterOps<_AlgPolicy>::next(__i); __j != __last1; ++__j) {
+        if (std::__invoke(__pred, std::__invoke(__proj1, *__i), std::__invoke(__proj1, *__j)))
+          ++__c1;
+      }
+      if (__c1 != __c2)
+        return false;
+    }
+  }
+
+  return true;
+}
+
+// 2+1 iterators, predicate. Not used by range algorithms.
+template <class _AlgPolicy, class _ForwardIterator1, class _Sentinel1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+__is_permutation(_ForwardIterator1 __first1, _Sentinel1 __last1, _ForwardIterator2 __first2,
+                 _BinaryPredicate&& __pred) {
+  // Shorten sequences as much as possible by lopping of any equal prefix.
+  for (; __first1 != __last1; ++__first1, (void)++__first2) {
+    if (!__pred(*__first1, *__first2))
+      break;
+  }
+
+  if (__first1 == __last1)
+    return true;
+
+  //  __first1 != __last1 && *__first1 != *__first2
+  using _D1 = __iter_diff_t<_ForwardIterator1>;
+  _D1 __l1 = _IterOps<_AlgPolicy>::distance(__first1, __last1);
+  if (__l1 == _D1(1))
+    return false;
+  auto __last2 = _IterOps<_AlgPolicy>::next(__first2, __l1);
+
+  return std::__is_permutation_impl<_AlgPolicy>(
+      std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
+      __pred, __identity(), __identity());
+}
+
+// 2+2 iterators, predicate, non-constant time `distance`.
+template <class _AlgPolicy,
+          class _Iter1, class _Sent1, class _Iter2, class _Sent2,
+          class _Proj1, class _Proj2, class _Pred>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+__is_permutation(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
+                 _Pred&& __pred, _Proj1&& __proj1, _Proj2&& __proj2,
+                 /*_ConstTimeDistance=*/false_type) {
+  // Shorten sequences as much as possible by lopping of any equal prefix.
+  while (__first1 != __last1 && __first2 != __last2) {
+    if (!std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
+      break;
+    ++__first1;
+    ++__first2;
+  }
+
+  if (__first1 == __last1)
+    return __first2 == __last2;
+  if (__first2 == __last2) // Second range is shorter
+    return false;
+
+  using _D1 = __iter_diff_t<_Iter1>;
+  _D1 __l1 = _IterOps<_AlgPolicy>::distance(__first1, __last1);
+
+  using _D2 = __iter_diff_t<_Iter2>;
+  _D2 __l2 = _IterOps<_AlgPolicy>::distance(__first2, __last2);
+  if (__l1 != __l2)
+    return false;
+
+  return std::__is_permutation_impl<_AlgPolicy>(
+      std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
+      __pred, __proj1, __proj2);
+}
+
+// 2+2 iterators, predicate, specialization for constant-time `distance` call.
+template <class _AlgPolicy,
+          class _Iter1, class _Sent1, class _Iter2, class _Sent2,
+          class _Proj1, class _Proj2, class _Pred>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+__is_permutation(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
+                 _Pred&& __pred, _Proj1&& __proj1, _Proj2&& __proj2,
+                 /*_ConstTimeDistance=*/true_type) {
+  if (std::distance(__first1, __last1) != std::distance(__first2, __last2))
+    return false;
+  return std::__is_permutation<_AlgPolicy>(
+      std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
+      __pred, __proj1, __proj2,
+      /*_ConstTimeDistance=*/false_type());
+}
+
+// 2+2 iterators, predicate
+template <class _AlgPolicy,
+          class _Iter1, class _Sent1, class _Iter2, class _Sent2,
+          class _Proj1, class _Proj2, class _Pred>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+__is_permutation(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
+                 _Pred&& __pred, _Proj1&& __proj1, _Proj2&& __proj2) {
+  return std::__is_permutation<_AlgPolicy>(
+      std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
+      __pred, __proj1, __proj2,
+      _ConstTimeDistance<_Iter1, _Sent1, _Iter2, _Sent2>());
+}
+
+// Public interface
+
+// 2+1 iterators, predicate
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+               _BinaryPredicate __pred) {
+  static_assert(__is_callable<_BinaryPredicate, decltype(*__first1), decltype(*__first2)>::value,
+      "The predicate has to be callable");
+
+  return std::__is_permutation<_ClassicAlgPolicy>(
+      std::move(__first1), std::move(__last1), std::move(__first2), __pred);
+}
+
+// 2+1 iterators
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2) {
+  return std::is_permutation(__first1, __last1, __first2, __equal_to());
+}
+
+#if _LIBCPP_STD_VER >= 14
+
+// 2+2 iterators
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool is_permutation(
+    _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
+  return std::__is_permutation<_ClassicAlgPolicy>(
+      std::move(__first1),
+      std::move(__last1),
+      std::move(__first2),
+      std::move(__last2),
+      __equal_to(),
+      __identity(),
+      __identity());
+}
+
+// 2+2 iterators, predicate
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+               _ForwardIterator2 __last2, _BinaryPredicate __pred) {
+  static_assert(__is_callable<_BinaryPredicate, decltype(*__first1), decltype(*__first2)>::value,
+      "The predicate has to be callable");
+
+  return std::__is_permutation<_ClassicAlgPolicy>(
+      std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2),
+      __pred, __identity(), __identity());
+}
+
+#endif // _LIBCPP_STD_VER >= 14
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_PERMUTATION_H

third_party/libcxx/__algorithm/is_sorted.h

@@ -0,0 +1,44 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_SORTED_H
+#define _LIBCPP___ALGORITHM_IS_SORTED_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/is_sorted_until.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+is_sorted(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    return _VSTD::__is_sorted_until<__comp_ref_type<_Compare> >(__first, __last, __comp) == __last;
+}
+
+template<class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+is_sorted(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::is_sorted(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_SORTED_H

third_party/libcxx/__algorithm/is_sorted_until.h

@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IS_SORTED_UNTIL_H
+#define _LIBCPP___ALGORITHM_IS_SORTED_UNTIL_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _ForwardIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+__is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+        {
+            if (__comp(*__i, *__first))
+                return __i;
+            __first = __i;
+        }
+    }
+    return __last;
+}
+
+template <class _ForwardIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    return _VSTD::__is_sorted_until<__comp_ref_type<_Compare> >(__first, __last, __comp);
+}
+
+template<class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::is_sorted_until(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IS_SORTED_UNTIL_H

third_party/libcxx/__algorithm/iter_swap.h

@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ITER_SWAP_H
+#define _LIBCPP___ALGORITHM_ITER_SWAP_H
+
+#include <__config>
+#include <__utility/declval.h>
+#include <__utility/swap.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 void iter_swap(_ForwardIterator1 __a,
+                                                                              _ForwardIterator2 __b)
+    //                                  _NOEXCEPT_(_NOEXCEPT_(swap(*__a, *__b)))
+    _NOEXCEPT_(_NOEXCEPT_(swap(*std::declval<_ForwardIterator1>(), *std::declval<_ForwardIterator2>()))) {
+  swap(*__a, *__b);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ITER_SWAP_H

third_party/libcxx/__algorithm/iterator_operations.h

@@ -0,0 +1,175 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_ITERATOR_OPERATIONS_H
+#define _LIBCPP___ALGORITHM_ITERATOR_OPERATIONS_H
+
+#include <__algorithm/iter_swap.h>
+#include <__algorithm/ranges_iterator_concept.h>
+#include <__config>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/iter_move.h>
+#include <__iterator/iter_swap.h>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <__iterator/prev.h>
+#include <__iterator/readable_traits.h>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_reference.h>
+#include <__type_traits/is_same.h>
+#include <__type_traits/remove_cvref.h>
+#include <__utility/declval.h>
+#include <__utility/forward.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy> struct _IterOps;
+
+#if _LIBCPP_STD_VER >= 20
+struct _RangeAlgPolicy {};
+
+template <>
+struct _IterOps<_RangeAlgPolicy> {
+
+  template <class _Iter>
+  using __value_type = iter_value_t<_Iter>;
+
+  template <class _Iter>
+  using __iterator_category = ranges::__iterator_concept<_Iter>;
+
+  template <class _Iter>
+  using __difference_type = iter_difference_t<_Iter>;
+
+  static constexpr auto advance = ranges::advance;
+  static constexpr auto distance = ranges::distance;
+  static constexpr auto __iter_move = ranges::iter_move;
+  static constexpr auto iter_swap = ranges::iter_swap;
+  static constexpr auto next = ranges::next;
+  static constexpr auto prev = ranges::prev;
+  static constexpr auto __advance_to = ranges::advance;
+};
+
+#endif
+
+struct _ClassicAlgPolicy {};
+
+template <>
+struct _IterOps<_ClassicAlgPolicy> {
+
+  template <class _Iter>
+  using __value_type = typename iterator_traits<_Iter>::value_type;
+
+  template <class _Iter>
+  using __iterator_category = typename iterator_traits<_Iter>::iterator_category;
+
+  template <class _Iter>
+  using __difference_type = typename iterator_traits<_Iter>::difference_type;
+
+  // advance
+  template <class _Iter, class _Distance>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+  static void advance(_Iter& __iter, _Distance __count) {
+    std::advance(__iter, __count);
+  }
+
+  // distance
+  template <class _Iter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+  static typename iterator_traits<_Iter>::difference_type distance(_Iter __first, _Iter __last) {
+    return std::distance(__first, __last);
+  }
+
+  template <class _Iter>
+  using __deref_t = decltype(*std::declval<_Iter&>());
+
+  template <class _Iter>
+  using __move_t = decltype(std::move(*std::declval<_Iter&>()));
+
+  template <class _Iter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+  static void __validate_iter_reference() {
+    static_assert(is_same<__deref_t<_Iter>, typename iterator_traits<__remove_cvref_t<_Iter> >::reference>::value,
+        "It looks like your iterator's `iterator_traits<It>::reference` does not match the return type of "
+        "dereferencing the iterator, i.e., calling `*it`. This is undefined behavior according to [input.iterators] "
+        "and can lead to dangling reference issues at runtime, so we are flagging this.");
+  }
+
+  // iter_move
+  template <class _Iter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 static
+  // If the result of dereferencing `_Iter` is a reference type, deduce the result of calling `std::move` on it. Note
+  // that the C++03 mode doesn't support `decltype(auto)` as the return type.
+  __enable_if_t<
+      is_reference<__deref_t<_Iter> >::value,
+      __move_t<_Iter> >
+  __iter_move(_Iter&& __i) {
+    __validate_iter_reference<_Iter>();
+
+    return std::move(*std::forward<_Iter>(__i));
+  }
+
+  template <class _Iter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 static
+  // If the result of dereferencing `_Iter` is a value type, deduce the return value of this function to also be a
+  // value -- otherwise, after `operator*` returns a temporary, this function would return a dangling reference to that
+  // temporary. Note that the C++03 mode doesn't support `auto` as the return type.
+  __enable_if_t<
+      !is_reference<__deref_t<_Iter> >::value,
+      __deref_t<_Iter> >
+  __iter_move(_Iter&& __i) {
+    __validate_iter_reference<_Iter>();
+
+    return *std::forward<_Iter>(__i);
+  }
+
+  // iter_swap
+  template <class _Iter1, class _Iter2>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+  static void iter_swap(_Iter1&& __a, _Iter2&& __b) {
+    std::iter_swap(std::forward<_Iter1>(__a), std::forward<_Iter2>(__b));
+  }
+
+  // next
+  template <class _Iterator>
+  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX14
+  _Iterator next(_Iterator, _Iterator __last) {
+    return __last;
+  }
+
+  template <class _Iter>
+  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX14
+  __remove_cvref_t<_Iter> next(_Iter&& __it,
+                          typename iterator_traits<__remove_cvref_t<_Iter> >::difference_type __n = 1) {
+    return std::next(std::forward<_Iter>(__it), __n);
+  }
+
+  // prev
+  template <class _Iter>
+  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX14
+  __remove_cvref_t<_Iter> prev(_Iter&& __iter,
+                 typename iterator_traits<__remove_cvref_t<_Iter> >::difference_type __n = 1) {
+    return std::prev(std::forward<_Iter>(__iter), __n);
+  }
+
+  template <class _Iter>
+  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX14
+  void __advance_to(_Iter& __first, _Iter __last) {
+    __first = __last;
+  }
+};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_ITERATOR_OPERATIONS_H

third_party/libcxx/__algorithm/lexicographical_compare.h

@@ -0,0 +1,62 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_LEXICOGRAPHICAL_COMPARE_H
+#define _LIBCPP___ALGORITHM_LEXICOGRAPHICAL_COMPARE_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator1, class _InputIterator2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+__lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
+                          _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
+{
+    for (; __first2 != __last2; ++__first1, (void) ++__first2)
+    {
+        if (__first1 == __last1 || __comp(*__first1, *__first2))
+            return true;
+        if (__comp(*__first2, *__first1))
+            return false;
+    }
+    return false;
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
+                        _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
+{
+    return _VSTD::__lexicographical_compare<__comp_ref_type<_Compare> >(__first1, __last1, __first2, __last2, __comp);
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
+                        _InputIterator2 __first2, _InputIterator2 __last2)
+{
+    return _VSTD::lexicographical_compare(__first1, __last1, __first2, __last2,
+                                         __less<typename iterator_traits<_InputIterator1>::value_type,
+                                                typename iterator_traits<_InputIterator2>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_LEXICOGRAPHICAL_COMPARE_H

third_party/libcxx/__algorithm/lexicographical_compare_three_way.h

@@ -0,0 +1,125 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_LEXICOGRAPHICAL_COMPARE_THREE_WAY_H
+#define _LIBCPP___ALGORITHM_LEXICOGRAPHICAL_COMPARE_THREE_WAY_H
+
+#include <__algorithm/min.h>
+#include <__algorithm/three_way_comp_ref_type.h>
+#include <__compare/compare_three_way.h>
+#include <__compare/ordering.h>
+#include <__concepts/arithmetic.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/common_type.h>
+#include <__type_traits/is_copy_constructible.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+// Fast path for random access iterators which computes the number of loop iterations up-front and
+// then skips the iterator comparisons inside the loop.
+template <class _InputIterator1, class _InputIterator2, class _Cmp>
+_LIBCPP_HIDE_FROM_ABI constexpr auto __lexicographical_compare_three_way_fast_path(
+    _InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _Cmp& __comp)
+    -> decltype(__comp(*__first1, *__first2)) {
+  static_assert(
+      signed_integral<__iter_diff_t<_InputIterator1>>, "Using a non-integral difference_type is undefined behavior.");
+  static_assert(
+      signed_integral<__iter_diff_t<_InputIterator2>>, "Using a non-integral difference_type is undefined behavior.");
+
+  using _Len1   = __iter_diff_t<_InputIterator1>;
+  using _Len2   = __iter_diff_t<_InputIterator2>;
+  using _Common = common_type_t<_Len1, _Len2>;
+
+  _Len1 __len1      = __last1 - __first1;
+  _Len2 __len2      = __last2 - __first2;
+  _Common __min_len = std::min<_Common>(__len1, __len2);
+
+  for (_Common __i = 0; __i < __min_len; ++__i) {
+    auto __c = __comp(*__first1, *__first2);
+    if (__c != 0) {
+      return __c;
+    }
+    ++__first1;
+    ++__first2;
+  }
+
+  return __len1 <=> __len2;
+}
+
+// Unoptimized implementation which compares the iterators against the end in every loop iteration
+template <class _InputIterator1, class _InputIterator2, class _Cmp>
+_LIBCPP_HIDE_FROM_ABI constexpr auto __lexicographical_compare_three_way_slow_path(
+    _InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _Cmp& __comp)
+    -> decltype(__comp(*__first1, *__first2)) {
+  while (true) {
+    bool __exhausted1 = __first1 == __last1;
+    bool __exhausted2 = __first2 == __last2;
+
+    if (__exhausted1 || __exhausted2) {
+      if (!__exhausted1)
+        return strong_ordering::greater;
+      if (!__exhausted2)
+        return strong_ordering::less;
+      return strong_ordering::equal;
+    }
+
+    auto __c = __comp(*__first1, *__first2);
+    if (__c != 0) {
+      return __c;
+    }
+
+    ++__first1;
+    ++__first2;
+  }
+}
+
+template <class _InputIterator1, class _InputIterator2, class _Cmp>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto lexicographical_compare_three_way(
+    _InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _Cmp __comp)
+    -> decltype(__comp(*__first1, *__first2)) {
+  static_assert(__comparison_category<decltype(__comp(*__first1, *__first2))>,
+                "The comparator passed to lexicographical_compare_three_way must return a comparison category type.");
+  static_assert(std::is_copy_constructible_v<_InputIterator1>, "Iterators must be copy constructible.");
+  static_assert(std::is_copy_constructible_v<_InputIterator2>, "Iterators must be copy constructible.");
+  __three_way_comp_ref_type<_Cmp> __wrapped_comp_ref(__comp);
+  if constexpr (__has_random_access_iterator_category<_InputIterator1>::value &&
+                __has_random_access_iterator_category<_InputIterator2>::value) {
+    return std::__lexicographical_compare_three_way_fast_path(
+        std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), __wrapped_comp_ref);
+  } else {
+    // Unoptimized implementation which compares the iterators against the end in every loop iteration
+    return std::__lexicographical_compare_three_way_slow_path(
+        std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), __wrapped_comp_ref);
+  }
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr auto lexicographical_compare_three_way(
+    _InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
+  return std::lexicographical_compare_three_way(
+      std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), std::compare_three_way());
+}
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_LEXICOGRAPHICAL_COMPARE_THREE_WAY_H

third_party/libcxx/__algorithm/lower_bound.h

@@ -0,0 +1,67 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_LOWER_BOUND_H
+#define _LIBCPP___ALGORITHM_LOWER_BOUND_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/half_positive.h>
+#include <__algorithm/iterator_operations.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_callable.h>
+#include <__type_traits/remove_reference.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _Iter, class _Sent, class _Type, class _Proj, class _Comp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+_Iter __lower_bound_impl(_Iter __first, _Sent __last, const _Type& __value, _Comp& __comp, _Proj& __proj) {
+  auto __len = _IterOps<_AlgPolicy>::distance(__first, __last);
+
+  while (__len != 0) {
+    auto __l2 = std::__half_positive(__len);
+    _Iter __m = __first;
+    _IterOps<_AlgPolicy>::advance(__m, __l2);
+    if (std::__invoke(__comp, std::__invoke(__proj, *__m), __value)) {
+      __first = ++__m;
+      __len -= __l2 + 1;
+    } else {
+      __len = __l2;
+    }
+  }
+  return __first;
+}
+
+template <class _ForwardIterator, class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+_ForwardIterator lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value, _Compare __comp) {
+  static_assert(__is_callable<_Compare, decltype(*__first), const _Tp&>::value,
+                "The comparator has to be callable");
+  auto __proj = std::__identity();
+  return std::__lower_bound_impl<_ClassicAlgPolicy>(__first, __last, __value, __comp, __proj);
+}
+
+template <class _ForwardIterator, class _Tp>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+_ForwardIterator lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
+  return std::lower_bound(__first, __last, __value,
+                          __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_LOWER_BOUND_H

third_party/libcxx/__algorithm/make_heap.h

@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MAKE_HEAP_H
+#define _LIBCPP___ALGORITHM_MAKE_HEAP_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/sift_down.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+void __make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp) {
+  __comp_ref_type<_Compare> __comp_ref = __comp;
+
+  using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
+  difference_type __n = __last - __first;
+  if (__n > 1) {
+    // start from the first parent, there is no need to consider children
+    for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start) {
+        std::__sift_down<_AlgPolicy>(__first, __comp_ref, __n, __first + __start);
+    }
+  }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
+  std::__make_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
+  std::make_heap(std::move(__first), std::move(__last),
+      __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MAKE_HEAP_H

third_party/libcxx/__algorithm/make_projected.h

@@ -0,0 +1,113 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MAKE_PROJECTED_H
+#define _LIBCPP___ALGORITHM_MAKE_PROJECTED_H
+
+#include <__concepts/same_as.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__type_traits/decay.h>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/integral_constant.h>
+#include <__type_traits/is_member_pointer.h>
+#include <__type_traits/is_same.h>
+#include <__utility/declval.h>
+#include <__utility/forward.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Pred, class _Proj>
+struct _ProjectedPred {
+  _Pred& __pred; // Can be a unary or a binary predicate.
+  _Proj& __proj;
+
+  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI _ProjectedPred(_Pred& __pred_arg, _Proj& __proj_arg)
+      : __pred(__pred_arg), __proj(__proj_arg) {}
+
+  template <class _Tp>
+  typename __invoke_of<_Pred&,
+                       decltype(std::__invoke(std::declval<_Proj&>(), std::declval<_Tp>()))
+  >::type
+  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI operator()(_Tp&& __v) const {
+    return std::__invoke(__pred, std::__invoke(__proj, std::forward<_Tp>(__v)));
+  }
+
+  template <class _T1, class _T2>
+  typename __invoke_of<_Pred&,
+                       decltype(std::__invoke(std::declval<_Proj&>(), std::declval<_T1>())),
+                       decltype(std::__invoke(std::declval<_Proj&>(), std::declval<_T2>()))
+  >::type
+  _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI operator()(_T1&& __lhs, _T2&& __rhs) const {
+    return std::__invoke(__pred,
+                      std::__invoke(__proj, std::forward<_T1>(__lhs)),
+                      std::__invoke(__proj, std::forward<_T2>(__rhs)));
+  }
+
+};
+
+template <class _Pred,
+          class _Proj,
+          __enable_if_t<!(!is_member_pointer<__decay_t<_Pred> >::value &&
+                            __is_identity<__decay_t<_Proj> >::value),
+                        int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _ProjectedPred<_Pred, _Proj>
+__make_projected(_Pred& __pred, _Proj& __proj) {
+  return _ProjectedPred<_Pred, _Proj>(__pred, __proj);
+}
+
+// Avoid creating the functor and just use the pristine comparator -- for certain algorithms, this would enable
+// optimizations that rely on the type of the comparator. Additionally, this results in less layers of indirection in
+// the call stack when the comparator is invoked, even in an unoptimized build.
+template <class _Pred,
+          class _Proj,
+          __enable_if_t<!is_member_pointer<__decay_t<_Pred> >::value &&
+                          __is_identity<__decay_t<_Proj> >::value,
+                        int> = 0>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Pred& __make_projected(_Pred& __pred, _Proj&) {
+  return __pred;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+
+template <class _Comp, class _Proj1, class _Proj2>
+_LIBCPP_HIDE_FROM_ABI constexpr
+decltype(auto) __make_projected_comp(_Comp& __comp, _Proj1& __proj1, _Proj2& __proj2) {
+  if constexpr (__is_identity<decay_t<_Proj1>>::value && __is_identity<decay_t<_Proj2>>::value &&
+                !is_member_pointer_v<decay_t<_Comp>>) {
+    // Avoid creating the lambda and just use the pristine comparator -- for certain algorithms, this would enable
+    // optimizations that rely on the type of the comparator.
+    return __comp;
+
+  } else {
+    return [&](auto&& __lhs, auto&& __rhs) {
+      return std::invoke(__comp,
+                        std::invoke(__proj1, std::forward<decltype(__lhs)>(__lhs)),
+                        std::invoke(__proj2, std::forward<decltype(__rhs)>(__rhs)));
+    };
+  }
+}
+
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#endif // _LIBCPP___ALGORITHM_MAKE_PROJECTED_H

third_party/libcxx/__algorithm/max.h

@@ -0,0 +1,71 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MAX_H
+#define _LIBCPP___ALGORITHM_MAX_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/max_element.h>
+#include <__config>
+#include <initializer_list>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+const _Tp&
+max(_LIBCPP_LIFETIMEBOUND const _Tp& __a, _LIBCPP_LIFETIMEBOUND const _Tp& __b, _Compare __comp)
+{
+    return __comp(__a, __b) ? __b : __a;
+}
+
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+const _Tp&
+max(_LIBCPP_LIFETIMEBOUND const _Tp& __a, _LIBCPP_LIFETIMEBOUND const _Tp& __b)
+{
+    return _VSTD::max(__a, __b, __less<_Tp>());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+_Tp
+max(initializer_list<_Tp> __t, _Compare __comp)
+{
+    return *_VSTD::__max_element<__comp_ref_type<_Compare> >(__t.begin(), __t.end(), __comp);
+}
+
+template<class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+_Tp
+max(initializer_list<_Tp> __t)
+{
+    return *_VSTD::max_element(__t.begin(), __t.end(), __less<_Tp>());
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_MAX_H

third_party/libcxx/__algorithm/max_element.h

@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MAX_ELEMENT_H
+#define _LIBCPP___ALGORITHM_MAX_ELEMENT_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _ForwardIterator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
+__max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    static_assert(__has_forward_iterator_category<_ForwardIterator>::value,
+        "std::max_element requires a ForwardIterator");
+    if (__first != __last)
+    {
+        _ForwardIterator __i = __first;
+        while (++__i != __last)
+            if (__comp(*__first, *__i))
+                __first = __i;
+    }
+    return __first;
+}
+
+template <class _ForwardIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
+max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+    return _VSTD::__max_element<__comp_ref_type<_Compare> >(__first, __last, __comp);
+}
+
+
+template <class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
+max_element(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::max_element(__first, __last,
+              __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MAX_ELEMENT_H

third_party/libcxx/__algorithm/merge.h

@@ -0,0 +1,70 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MERGE_H
+#define _LIBCPP___ALGORITHM_MERGE_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/copy.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+_OutputIterator
+__merge(_InputIterator1 __first1, _InputIterator1 __last1,
+        _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    for (; __first1 != __last1; ++__result)
+    {
+        if (__first2 == __last2)
+            return _VSTD::copy(__first1, __last1, __result);
+        if (__comp(*__first2, *__first1))
+        {
+            *__result = *__first2;
+            ++__first2;
+        }
+        else
+        {
+            *__result = *__first1;
+            ++__first1;
+        }
+    }
+    return _VSTD::copy(__first2, __last2, __result);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+_OutputIterator
+merge(_InputIterator1 __first1, _InputIterator1 __last1,
+      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
+{
+    return _VSTD::__merge<__comp_ref_type<_Compare> >(__first1, __last1, __first2, __last2, __result, __comp);
+}
+
+template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+_OutputIterator
+merge(_InputIterator1 __first1, _InputIterator1 __last1,
+      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
+{
+    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
+    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
+    return _VSTD::merge(__first1, __last1, __first2, __last2, __result, __less<__v1, __v2>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MERGE_H

third_party/libcxx/__algorithm/min.h

@@ -0,0 +1,71 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MIN_H
+#define _LIBCPP___ALGORITHM_MIN_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/min_element.h>
+#include <__config>
+#include <initializer_list>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+const _Tp&
+min(_LIBCPP_LIFETIMEBOUND const _Tp& __a, _LIBCPP_LIFETIMEBOUND const _Tp& __b, _Compare __comp)
+{
+    return __comp(__b, __a) ? __b : __a;
+}
+
+template <class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+const _Tp&
+min(_LIBCPP_LIFETIMEBOUND const _Tp& __a, _LIBCPP_LIFETIMEBOUND const _Tp& __b)
+{
+    return _VSTD::min(__a, __b, __less<_Tp>());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+_Tp
+min(initializer_list<_Tp> __t, _Compare __comp)
+{
+    return *_VSTD::__min_element<__comp_ref_type<_Compare> >(__t.begin(), __t.end(), __comp);
+}
+
+template<class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+_Tp
+min(initializer_list<_Tp> __t)
+{
+    return *_VSTD::min_element(__t.begin(), __t.end(), __less<_Tp>());
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_MIN_H

third_party/libcxx/__algorithm/min_element.h

@@ -0,0 +1,70 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MIN_ELEMENT_H
+#define _LIBCPP___ALGORITHM_MIN_ELEMENT_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_callable.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Comp, class _Iter, class _Sent, class _Proj>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+_Iter __min_element(_Iter __first, _Sent __last, _Comp __comp, _Proj& __proj) {
+  if (__first == __last)
+    return __first;
+
+  _Iter __i = __first;
+  while (++__i != __last)
+    if (std::__invoke(__comp, std::__invoke(__proj, *__i), std::__invoke(__proj, *__first)))
+      __first = __i;
+
+  return __first;
+}
+
+template <class _Comp, class _Iter, class _Sent>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+_Iter __min_element(_Iter __first, _Sent __last, _Comp __comp) {
+  auto __proj = __identity();
+  return std::__min_element<_Comp>(std::move(__first), std::move(__last), __comp, __proj);
+}
+
+template <class _ForwardIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
+min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
+{
+  static_assert(__has_forward_iterator_category<_ForwardIterator>::value,
+      "std::min_element requires a ForwardIterator");
+  static_assert(__is_callable<_Compare, decltype(*__first), decltype(*__first)>::value,
+              "The comparator has to be callable");
+
+  return std::__min_element<__comp_ref_type<_Compare> >(std::move(__first), std::move(__last), __comp);
+}
+
+template <class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator
+min_element(_ForwardIterator __first, _ForwardIterator __last)
+{
+    return _VSTD::min_element(__first, __last,
+              __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MIN_ELEMENT_H

third_party/libcxx/__algorithm/min_max_result.h

@@ -0,0 +1,56 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MIN_MAX_RESULT_H
+#define _LIBCPP___ALGORITHM_MIN_MAX_RESULT_H
+
+#include <__concepts/convertible_to.h>
+#include <__config>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+namespace ranges {
+
+template <class _T1>
+struct min_max_result {
+  _LIBCPP_NO_UNIQUE_ADDRESS _T1 min;
+  _LIBCPP_NO_UNIQUE_ADDRESS _T1 max;
+
+  template <class _T2>
+    requires convertible_to<const _T1&, _T2>
+  _LIBCPP_HIDE_FROM_ABI constexpr operator min_max_result<_T2>() const & {
+    return {min, max};
+  }
+
+  template <class _T2>
+    requires convertible_to<_T1, _T2>
+  _LIBCPP_HIDE_FROM_ABI constexpr operator min_max_result<_T2>() && {
+    return {std::move(min), std::move(max)};
+  }
+};
+
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_MIN_MAX_RESULT_H

third_party/libcxx/__algorithm/minmax.h

@@ -0,0 +1,69 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MINMAX_H
+#define _LIBCPP___ALGORITHM_MINMAX_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/minmax_element.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__type_traits/is_callable.h>
+#include <__utility/pair.h>
+#include <initializer_list>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+pair<const _Tp&, const _Tp&>
+minmax(_LIBCPP_LIFETIMEBOUND const _Tp& __a, _LIBCPP_LIFETIMEBOUND const _Tp& __b, _Compare __comp)
+{
+    return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a) :
+                              pair<const _Tp&, const _Tp&>(__a, __b);
+}
+
+template<class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+pair<const _Tp&, const _Tp&>
+minmax(_LIBCPP_LIFETIMEBOUND const _Tp& __a, _LIBCPP_LIFETIMEBOUND const _Tp& __b)
+{
+    return std::minmax(__a, __b, __less<_Tp>());
+}
+
+#ifndef _LIBCPP_CXX03_LANG
+
+template<class _Tp, class _Compare>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+pair<_Tp, _Tp> minmax(initializer_list<_Tp> __t, _Compare __comp) {
+    static_assert(__is_callable<_Compare, _Tp, _Tp>::value, "The comparator has to be callable");
+    __identity __proj;
+    auto __ret = std::__minmax_element_impl(__t.begin(), __t.end(), __comp, __proj);
+    return pair<_Tp, _Tp>(*__ret.first, *__ret.second);
+}
+
+template<class _Tp>
+_LIBCPP_NODISCARD_EXT inline
+_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14
+pair<_Tp, _Tp>
+minmax(initializer_list<_Tp> __t)
+{
+    return std::minmax(__t, __less<_Tp>());
+}
+
+#endif // _LIBCPP_CXX03_LANG
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MINMAX_H

third_party/libcxx/__algorithm/minmax_element.h

@@ -0,0 +1,102 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
+#define _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
+
+#include <__algorithm/comp.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_callable.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Comp, class _Proj>
+class _MinmaxElementLessFunc {
+  _Comp& __comp_;
+  _Proj& __proj_;
+
+public:
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
+  _MinmaxElementLessFunc(_Comp& __comp, _Proj& __proj) : __comp_(__comp), __proj_(__proj) {}
+
+  template <class _Iter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+  bool operator()(_Iter& __it1, _Iter& __it2) {
+    return std::__invoke(__comp_, std::__invoke(__proj_, *__it1), std::__invoke(__proj_, *__it2));
+  }
+};
+
+template <class _Iter, class _Sent, class _Proj, class _Comp>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+pair<_Iter, _Iter> __minmax_element_impl(_Iter __first, _Sent __last, _Comp& __comp, _Proj& __proj) {
+  auto __less = _MinmaxElementLessFunc<_Comp, _Proj>(__comp, __proj);
+
+  pair<_Iter, _Iter> __result(__first, __first);
+  if (__first == __last || ++__first == __last)
+    return __result;
+
+  if (__less(__first, __result.first))
+    __result.first = __first;
+  else
+    __result.second = __first;
+
+  while (++__first != __last) {
+    _Iter __i = __first;
+    if (++__first == __last) {
+      if (__less(__i, __result.first))
+        __result.first = __i;
+      else if (!__less(__i, __result.second))
+        __result.second = __i;
+      return __result;
+    }
+
+    if (__less(__first, __i)) {
+      if (__less(__first, __result.first))
+        __result.first = __first;
+    if (!__less(__i, __result.second))
+      __result.second = __i;
+    } else {
+      if (__less(__i, __result.first))
+        __result.first = __i;
+      if (!__less(__first, __result.second))
+        __result.second = __first;
+    }
+  }
+
+  return __result;
+}
+
+template <class _ForwardIterator, class _Compare>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+pair<_ForwardIterator, _ForwardIterator>
+minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) {
+  static_assert(__has_forward_iterator_category<_ForwardIterator>::value,
+                "std::minmax_element requires a ForwardIterator");
+  static_assert(__is_callable<_Compare, decltype(*__first), decltype(*__first)>::value,
+                "The comparator has to be callable");
+  auto __proj = __identity();
+  return std::__minmax_element_impl(__first, __last, __comp, __proj);
+}
+
+template <class _ForwardIterator>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+pair<_ForwardIterator, _ForwardIterator> minmax_element(_ForwardIterator __first, _ForwardIterator __last) {
+    return std::minmax_element(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H

third_party/libcxx/__algorithm/mismatch.h

@@ -0,0 +1,63 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MISMATCH_H
+#define _LIBCPP___ALGORITHM_MISMATCH_H
+
+#include <__algorithm/comp.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred) {
+  for (; __first1 != __last1; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      break;
+  return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2) {
+  return std::mismatch(__first1, __last1, __first2, __equal_to());
+}
+
+#if _LIBCPP_STD_VER >= 14
+template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
+             _BinaryPredicate __pred) {
+  for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      break;
+  return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
+}
+
+template <class _InputIterator1, class _InputIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY
+    _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator1, _InputIterator2>
+    mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) {
+  return std::mismatch(__first1, __last1, __first2, __last2, __equal_to());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_MISMATCH_H

third_party/libcxx/__algorithm/move.h

@@ -0,0 +1,129 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MOVE_H
+#define _LIBCPP___ALGORITHM_MOVE_H
+
+#include <__algorithm/copy_move_common.h>
+#include <__algorithm/for_each_segment.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/min.h>
+#include <__config>
+#include <__iterator/segmented_iterator.h>
+#include <__type_traits/common_type.h>
+#include <__type_traits/is_copy_constructible.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+__move(_InIter __first, _Sent __last, _OutIter __result);
+
+template <class _AlgPolicy>
+struct __move_loop {
+  template <class _InIter, class _Sent, class _OutIter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _Sent __last, _OutIter __result) const {
+    while (__first != __last) {
+      *__result = _IterOps<_AlgPolicy>::__iter_move(__first);
+      ++__first;
+      ++__result;
+    }
+    return std::make_pair(std::move(__first), std::move(__result));
+  }
+
+  template <class _InIter, class _OutIter>
+  struct _MoveSegment {
+    using _Traits = __segmented_iterator_traits<_InIter>;
+
+    _OutIter& __result_;
+
+    _LIBCPP_HIDE_FROM_ABI _MoveSegment(_OutIter& __result) : __result_(__result) {}
+
+    _LIBCPP_HIDE_FROM_ABI void
+    operator()(typename _Traits::__local_iterator __lfirst, typename _Traits::__local_iterator __llast) {
+      __result_ = std::__move<_AlgPolicy>(__lfirst, __llast, std::move(__result_)).second;
+    }
+  };
+
+  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
+    std::__for_each_segment(__first, __last, _MoveSegment<_InIter, _OutIter>(__result));
+    return std::make_pair(__last, std::move(__result));
+  }
+
+  template <class _InIter,
+            class _OutIter,
+            __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
+                              !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
+                          int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) {
+    using _Traits = __segmented_iterator_traits<_OutIter>;
+    using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
+
+    if (__first == __last)
+      return std::make_pair(std::move(__first), std::move(__result));
+
+    auto __local_first      = _Traits::__local(__result);
+    auto __segment_iterator = _Traits::__segment(__result);
+    while (true) {
+      auto __local_last = _Traits::__end(__segment_iterator);
+      auto __size       = std::min<_DiffT>(__local_last - __local_first, __last - __first);
+      auto __iters      = std::__move<_AlgPolicy>(__first, __first + __size, __local_first);
+      __first           = std::move(__iters.first);
+
+      if (__first == __last)
+        return std::make_pair(std::move(__first), _Traits::__compose(__segment_iterator, std::move(__iters.second)));
+
+      __local_first = _Traits::__begin(++__segment_iterator);
+    }
+  }
+};
+
+struct __move_trivial {
+  // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
+  template <class _In, class _Out,
+            __enable_if_t<__can_lower_move_assignment_to_memmove<_In, _Out>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+  operator()(_In* __first, _In* __last, _Out* __result) const {
+    return std::__copy_trivial_impl(__first, __last, __result);
+  }
+};
+
+template <class _AlgPolicy, class _InIter, class _Sent, class _OutIter>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+__move(_InIter __first, _Sent __last, _OutIter __result) {
+  return std::__dispatch_copy_or_move<_AlgPolicy, __move_loop<_AlgPolicy>, __move_trivial>(
+      std::move(__first), std::move(__last), std::move(__result));
+}
+
+template <class _InputIterator, class _OutputIterator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
+move(_InputIterator __first, _InputIterator __last, _OutputIterator __result) {
+  static_assert(is_copy_constructible<_InputIterator>::value, "Iterators has to be copy constructible.");
+  static_assert(is_copy_constructible<_OutputIterator>::value, "The output iterator has to be copy constructible.");
+
+  return std::__move<_ClassicAlgPolicy>(std::move(__first), std::move(__last), std::move(__result)).second;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_MOVE_H

third_party/libcxx/__algorithm/move_backward.h

@@ -0,0 +1,139 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_MOVE_BACKWARD_H
+#define _LIBCPP___ALGORITHM_MOVE_BACKWARD_H
+
+#include <__algorithm/copy_move_common.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/min.h>
+#include <__config>
+#include <__iterator/segmented_iterator.h>
+#include <__type_traits/common_type.h>
+#include <__type_traits/is_copy_constructible.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _BidirectionalIterator1, class _Sentinel, class _BidirectionalIterator2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_BidirectionalIterator1, _BidirectionalIterator2>
+__move_backward(_BidirectionalIterator1 __first, _Sentinel __last, _BidirectionalIterator2 __result);
+
+template <class _AlgPolicy>
+struct __move_backward_loop {
+  template <class _InIter, class _Sent, class _OutIter>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _Sent __last, _OutIter __result) const {
+    auto __last_iter          = _IterOps<_AlgPolicy>::next(__first, __last);
+    auto __original_last_iter = __last_iter;
+
+    while (__first != __last_iter) {
+      *--__result = _IterOps<_AlgPolicy>::__iter_move(--__last_iter);
+    }
+
+    return std::make_pair(std::move(__original_last_iter), std::move(__result));
+  }
+
+  template <class _InIter, class _OutIter, __enable_if_t<__is_segmented_iterator<_InIter>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) const {
+    using _Traits = __segmented_iterator_traits<_InIter>;
+    auto __sfirst = _Traits::__segment(__first);
+    auto __slast  = _Traits::__segment(__last);
+    if (__sfirst == __slast) {
+      auto __iters =
+          std::__move_backward<_AlgPolicy>(_Traits::__local(__first), _Traits::__local(__last), std::move(__result));
+      return std::make_pair(__last, __iters.second);
+    }
+
+    __result =
+        std::__move_backward<_AlgPolicy>(_Traits::__begin(__slast), _Traits::__local(__last), std::move(__result))
+            .second;
+    --__slast;
+    while (__sfirst != __slast) {
+      __result =
+          std::__move_backward<_AlgPolicy>(_Traits::__begin(__slast), _Traits::__end(__slast), std::move(__result))
+              .second;
+      --__slast;
+    }
+    __result = std::__move_backward<_AlgPolicy>(_Traits::__local(__first), _Traits::__end(__slast), std::move(__result))
+                   .second;
+    return std::make_pair(__last, std::move(__result));
+  }
+
+  template <class _InIter,
+            class _OutIter,
+            __enable_if_t<__has_random_access_iterator_category<_InIter>::value &&
+                              !__is_segmented_iterator<_InIter>::value && __is_segmented_iterator<_OutIter>::value,
+                          int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_InIter, _OutIter>
+  operator()(_InIter __first, _InIter __last, _OutIter __result) {
+    using _Traits = __segmented_iterator_traits<_OutIter>;
+    using _DiffT  = typename common_type<__iter_diff_t<_InIter>, __iter_diff_t<_OutIter> >::type;
+
+    // When the range contains no elements, __result might not be a valid iterator
+    if (__first == __last)
+      return std::make_pair(__first, __result);
+
+    auto __orig_last = __last;
+
+    auto __local_last       = _Traits::__local(__result);
+    auto __segment_iterator = _Traits::__segment(__result);
+    while (true) {
+      auto __local_first = _Traits::__begin(__segment_iterator);
+      auto __size        = std::min<_DiffT>(__local_last - __local_first, __last - __first);
+      auto __iter        = std::__move_backward<_AlgPolicy>(__last - __size, __last, __local_last).second;
+      __last -= __size;
+
+      if (__first == __last)
+        return std::make_pair(std::move(__orig_last), _Traits::__compose(__segment_iterator, std::move(__iter)));
+
+      __local_last = _Traits::__end(--__segment_iterator);
+    }
+  }
+};
+
+struct __move_backward_trivial {
+  // At this point, the iterators have been unwrapped so any `contiguous_iterator` has been unwrapped to a pointer.
+  template <class _In, class _Out,
+            __enable_if_t<__can_lower_move_assignment_to_memmove<_In, _Out>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_In*, _Out*>
+  operator()(_In* __first, _In* __last, _Out* __result) const {
+    return std::__copy_backward_trivial_impl(__first, __last, __result);
+  }
+};
+
+template <class _AlgPolicy, class _BidirectionalIterator1, class _Sentinel, class _BidirectionalIterator2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_BidirectionalIterator1, _BidirectionalIterator2>
+__move_backward(_BidirectionalIterator1 __first, _Sentinel __last, _BidirectionalIterator2 __result) {
+  static_assert(std::is_copy_constructible<_BidirectionalIterator1>::value &&
+                std::is_copy_constructible<_BidirectionalIterator1>::value, "Iterators must be copy constructible.");
+
+  return std::__dispatch_copy_or_move<_AlgPolicy, __move_backward_loop<_AlgPolicy>, __move_backward_trivial>(
+      std::move(__first), std::move(__last), std::move(__result));
+}
+
+template <class _BidirectionalIterator1, class _BidirectionalIterator2>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _BidirectionalIterator2
+move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last, _BidirectionalIterator2 __result) {
+  return std::__move_backward<_ClassicAlgPolicy>(std::move(__first), std::move(__last), std::move(__result)).second;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_MOVE_BACKWARD_H

third_party/libcxx/__algorithm/next_permutation.h

@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_NEXT_PERMUTATION_H
+#define _LIBCPP___ALGORITHM_NEXT_PERMUTATION_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/reverse.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _Compare, class _BidirectionalIterator, class _Sentinel>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_BidirectionalIterator, bool>
+__next_permutation(_BidirectionalIterator __first, _Sentinel __last, _Compare&& __comp)
+{
+    using _Result = pair<_BidirectionalIterator, bool>;
+
+    _BidirectionalIterator __last_iter = _IterOps<_AlgPolicy>::next(__first, __last);
+    _BidirectionalIterator __i = __last_iter;
+    if (__first == __last || __first == --__i)
+        return _Result(std::move(__last_iter), false);
+
+    while (true)
+    {
+        _BidirectionalIterator __ip1 = __i;
+        if (__comp(*--__i, *__ip1))
+        {
+            _BidirectionalIterator __j = __last_iter;
+            while (!__comp(*__i, *--__j))
+                ;
+            _IterOps<_AlgPolicy>::iter_swap(__i, __j);
+            std::__reverse<_AlgPolicy>(__ip1, __last_iter);
+            return _Result(std::move(__last_iter), true);
+        }
+        if (__i == __first)
+        {
+            std::__reverse<_AlgPolicy>(__first, __last_iter);
+            return _Result(std::move(__last_iter), false);
+        }
+    }
+}
+
+template <class _BidirectionalIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+  return std::__next_permutation<_ClassicAlgPolicy>(
+      std::move(__first), std::move(__last), static_cast<__comp_ref_type<_Compare> >(__comp)).second;
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    return _VSTD::next_permutation(__first, __last,
+                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_NEXT_PERMUTATION_H

third_party/libcxx/__algorithm/none_of.h

@@ -0,0 +1,32 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_NONE_OF_H
+#define _LIBCPP___ALGORITHM_NONE_OF_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _Predicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
+none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred) {
+  for (; __first != __last; ++__first)
+    if (__pred(*__first))
+      return false;
+  return true;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_NONE_OF_H

third_party/libcxx/__algorithm/nth_element.h

@@ -0,0 +1,258 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_NTH_ELEMENT_H
+#define _LIBCPP___ALGORITHM_NTH_ELEMENT_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/sort.h>
+#include <__config>
+#include <__debug>
+#include <__debug_utils/randomize_range.h>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _Compare, class _RandomAccessIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
+__nth_element_find_guard(_RandomAccessIterator& __i, _RandomAccessIterator& __j,
+                         _RandomAccessIterator __m, _Compare __comp)
+{
+    // manually guard downward moving __j against __i
+    while (true) {
+        if (__i == --__j) {
+            return false;
+        }
+        if (__comp(*__j, *__m)) {
+            return true;  // found guard for downward moving __j, now use unguarded partition
+        }
+    }
+}
+
+template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
+__nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
+{
+    using _Ops = _IterOps<_AlgPolicy>;
+
+    // _Compare is known to be a reference type
+    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
+    const difference_type __limit = 7;
+    while (true)
+    {
+        if (__nth == __last)
+            return;
+        difference_type __len = __last - __first;
+        switch (__len)
+        {
+        case 0:
+        case 1:
+            return;
+        case 2:
+            if (__comp(*--__last, *__first))
+                _Ops::iter_swap(__first, __last);
+            return;
+        case 3:
+            {
+            _RandomAccessIterator __m = __first;
+            std::__sort3<_AlgPolicy, _Compare>(__first, ++__m, --__last, __comp);
+            return;
+            }
+        }
+        if (__len <= __limit)
+        {
+            std::__selection_sort<_AlgPolicy, _Compare>(__first, __last, __comp);
+            return;
+        }
+        // __len > __limit >= 3
+        _RandomAccessIterator __m = __first + __len/2;
+        _RandomAccessIterator __lm1 = __last;
+        unsigned __n_swaps = std::__sort3<_AlgPolicy, _Compare>(__first, __m, --__lm1, __comp);
+        // *__m is median
+        // partition [__first, __m) < *__m and *__m <= [__m, __last)
+        // (this inhibits tossing elements equivalent to __m around unnecessarily)
+        _RandomAccessIterator __i = __first;
+        _RandomAccessIterator __j = __lm1;
+        // j points beyond range to be tested, *__lm1 is known to be <= *__m
+        // The search going up is known to be guarded but the search coming down isn't.
+        // Prime the downward search with a guard.
+        if (!__comp(*__i, *__m))  // if *__first == *__m
+        {
+            // *__first == *__m, *__first doesn't go in first part
+            if (_VSTD::__nth_element_find_guard<_Compare>(__i, __j, __m, __comp)) {
+                _Ops::iter_swap(__i, __j);
+                ++__n_swaps;
+            } else {
+                // *__first == *__m, *__m <= all other elements
+                // Partition instead into [__first, __i) == *__first and *__first < [__i, __last)
+                ++__i;  // __first + 1
+                __j = __last;
+                if (!__comp(*__first, *--__j)) {  // we need a guard if *__first == *(__last-1)
+                    while (true) {
+                        if (__i == __j) {
+                            return;  // [__first, __last) all equivalent elements
+                        } else if (__comp(*__first, *__i)) {
+                            _Ops::iter_swap(__i, __j);
+                            ++__n_swaps;
+                            ++__i;
+                            break;
+                        }
+                        ++__i;
+                    }
+                }
+                // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
+                if (__i == __j) {
+                    return;
+                }
+                while (true) {
+                    while (!__comp(*__first, *__i))
+                        ++__i;
+                    while (__comp(*__first, *--__j))
+                        ;
+                    if (__i >= __j)
+                        break;
+                    _Ops::iter_swap(__i, __j);
+                    ++__n_swaps;
+                    ++__i;
+                }
+                // [__first, __i) == *__first and *__first < [__i, __last)
+                // The first part is sorted,
+                if (__nth < __i) {
+                    return;
+                }
+                // __nth_element the second part
+                // _VSTD::__nth_element<_Compare>(__i, __nth, __last, __comp);
+                __first = __i;
+                continue;
+            }
+        }
+        ++__i;
+        // j points beyond range to be tested, *__lm1 is known to be <= *__m
+        // if not yet partitioned...
+        if (__i < __j)
+        {
+            // known that *(__i - 1) < *__m
+            while (true)
+            {
+                // __m still guards upward moving __i
+                while (__comp(*__i, *__m))
+                    ++__i;
+                // It is now known that a guard exists for downward moving __j
+                while (!__comp(*--__j, *__m))
+                    ;
+                if (__i >= __j)
+                    break;
+                _Ops::iter_swap(__i, __j);
+                ++__n_swaps;
+                // It is known that __m != __j
+                // If __m just moved, follow it
+                if (__m == __i)
+                    __m = __j;
+                ++__i;
+            }
+        }
+        // [__first, __i) < *__m and *__m <= [__i, __last)
+        if (__i != __m && __comp(*__m, *__i))
+        {
+            _Ops::iter_swap(__i, __m);
+            ++__n_swaps;
+        }
+        // [__first, __i) < *__i and *__i <= [__i+1, __last)
+        if (__nth == __i)
+            return;
+        if (__n_swaps == 0)
+        {
+            // We were given a perfectly partitioned sequence.  Coincidence?
+            if (__nth < __i)
+            {
+                // Check for [__first, __i) already sorted
+                __j = __m = __first;
+                while (true) {
+                    if (++__j == __i) {
+                        // [__first, __i) sorted
+                        return;
+                    }
+                    if (__comp(*__j, *__m)) {
+                        // not yet sorted, so sort
+                        break;
+                    }
+                    __m = __j;
+                }
+            }
+            else
+            {
+                // Check for [__i, __last) already sorted
+                __j = __m = __i;
+                while (true) {
+                    if (++__j == __last) {
+                        // [__i, __last) sorted
+                        return;
+                    }
+                    if (__comp(*__j, *__m)) {
+                        // not yet sorted, so sort
+                        break;
+                    }
+                    __m = __j;
+                }
+            }
+        }
+        // __nth_element on range containing __nth
+        if (__nth < __i)
+        {
+            // _VSTD::__nth_element<_Compare>(__first, __nth, __i, __comp);
+            __last = __i;
+        }
+        else
+        {
+            // _VSTD::__nth_element<_Compare>(__i+1, __nth, __last, __comp);
+            __first = ++__i;
+        }
+    }
+}
+
+template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void __nth_element_impl(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last,
+                        _Compare& __comp) {
+  if (__nth == __last)
+    return;
+
+  std::__debug_randomize_range<_AlgPolicy>(__first, __last);
+
+  std::__nth_element<_AlgPolicy, __comp_ref_type<_Compare> >(__first, __nth, __last, __comp);
+
+  std::__debug_randomize_range<_AlgPolicy>(__first, __nth);
+  if (__nth != __last) {
+    std::__debug_randomize_range<_AlgPolicy>(++__nth, __last);
+  }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last,
+                 _Compare __comp) {
+  std::__nth_element_impl<_ClassicAlgPolicy>(std::move(__first), std::move(__nth), std::move(__last), __comp);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last) {
+  std::nth_element(std::move(__first), std::move(__nth), std::move(__last), __less<typename
+      iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_NTH_ELEMENT_H

third_party/libcxx/__algorithm/partial_sort.h

@@ -0,0 +1,97 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PARTIAL_SORT_H
+#define _LIBCPP___ALGORITHM_PARTIAL_SORT_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/make_heap.h>
+#include <__algorithm/sift_down.h>
+#include <__algorithm/sort_heap.h>
+#include <__config>
+#include <__debug>
+#include <__debug_utils/randomize_range.h>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_copy_assignable.h>
+#include <__type_traits/is_copy_constructible.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _Compare, class _RandomAccessIterator, class _Sentinel>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+_RandomAccessIterator __partial_sort_impl(
+    _RandomAccessIterator __first, _RandomAccessIterator __middle, _Sentinel __last, _Compare&& __comp) {
+  if (__first == __middle) {
+    return _IterOps<_AlgPolicy>::next(__middle, __last);
+  }
+
+  std::__make_heap<_AlgPolicy>(__first, __middle, __comp);
+
+  typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first;
+  _RandomAccessIterator __i = __middle;
+  for (; __i != __last; ++__i)
+  {
+      if (__comp(*__i, *__first))
+      {
+          _IterOps<_AlgPolicy>::iter_swap(__i, __first);
+          std::__sift_down<_AlgPolicy>(__first, __comp, __len, __first);
+      }
+  }
+  std::__sort_heap<_AlgPolicy>(std::move(__first), std::move(__middle), __comp);
+
+  return __i;
+}
+
+template <class _AlgPolicy, class _Compare, class _RandomAccessIterator, class _Sentinel>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+_RandomAccessIterator __partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _Sentinel __last,
+                                     _Compare& __comp) {
+  if (__first == __middle)
+      return _IterOps<_AlgPolicy>::next(__middle, __last);
+
+  std::__debug_randomize_range<_AlgPolicy>(__first, __last);
+
+  auto __last_iter =
+      std::__partial_sort_impl<_AlgPolicy>(__first, __middle, __last, static_cast<__comp_ref_type<_Compare> >(__comp));
+
+  std::__debug_randomize_range<_AlgPolicy>(__middle, __last);
+
+  return __last_iter;
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
+             _Compare __comp)
+{
+  static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
+  static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
+
+  (void)std::__partial_sort<_ClassicAlgPolicy>(std::move(__first), std::move(__middle), std::move(__last), __comp);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+void
+partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
+{
+    _VSTD::partial_sort(__first, __middle, __last,
+                        __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PARTIAL_SORT_H

third_party/libcxx/__algorithm/partial_sort_copy.h

@@ -0,0 +1,88 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_H
+#define _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/make_heap.h>
+#include <__algorithm/make_projected.h>
+#include <__algorithm/sift_down.h>
+#include <__algorithm/sort_heap.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_callable.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _Compare,
+          class _InputIterator, class _Sentinel1, class _RandomAccessIterator, class _Sentinel2,
+          class _Proj1, class _Proj2>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator, _RandomAccessIterator>
+__partial_sort_copy(_InputIterator __first, _Sentinel1 __last,
+                    _RandomAccessIterator __result_first, _Sentinel2 __result_last,
+                    _Compare&& __comp, _Proj1&& __proj1, _Proj2&& __proj2)
+{
+    _RandomAccessIterator __r = __result_first;
+    auto&& __projected_comp = std::__make_projected(__comp, __proj2);
+
+    if (__r != __result_last)
+    {
+        for (; __first != __last && __r != __result_last; ++__first, (void) ++__r)
+            *__r = *__first;
+        std::__make_heap<_AlgPolicy>(__result_first, __r, __projected_comp);
+        typename iterator_traits<_RandomAccessIterator>::difference_type __len = __r - __result_first;
+        for (; __first != __last; ++__first)
+            if (std::__invoke(__comp, std::__invoke(__proj1, *__first), std::__invoke(__proj2, *__result_first))) {
+                *__result_first = *__first;
+                std::__sift_down<_AlgPolicy>(__result_first, __projected_comp, __len, __result_first);
+            }
+        std::__sort_heap<_AlgPolicy>(__result_first, __r, __projected_comp);
+    }
+
+    return pair<_InputIterator, _RandomAccessIterator>(
+        _IterOps<_AlgPolicy>::next(std::move(__first), std::move(__last)), std::move(__r));
+}
+
+template <class _InputIterator, class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+_RandomAccessIterator
+partial_sort_copy(_InputIterator __first, _InputIterator __last,
+                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
+{
+  static_assert(__is_callable<_Compare, decltype(*__first), decltype(*__result_first)>::value,
+                "Comparator has to be callable");
+
+  auto __result = std::__partial_sort_copy<_ClassicAlgPolicy>(__first, __last, __result_first, __result_last,
+      static_cast<__comp_ref_type<_Compare> >(__comp), __identity(), __identity());
+  return __result.second;
+}
+
+template <class _InputIterator, class _RandomAccessIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+_RandomAccessIterator
+partial_sort_copy(_InputIterator __first, _InputIterator __last,
+                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
+{
+    return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
+                                   __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_H

third_party/libcxx/__algorithm/partition.h

@@ -0,0 +1,97 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PARTITION_H
+#define _LIBCPP___ALGORITHM_PARTITION_H
+
+#include <__algorithm/iterator_operations.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Predicate, class _AlgPolicy, class _ForwardIterator, class _Sentinel>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_ForwardIterator, _ForwardIterator>
+__partition_impl(_ForwardIterator __first, _Sentinel __last, _Predicate __pred, forward_iterator_tag)
+{
+    while (true)
+    {
+        if (__first == __last)
+            return std::make_pair(std::move(__first), std::move(__first));
+        if (!__pred(*__first))
+            break;
+        ++__first;
+    }
+
+    _ForwardIterator __p = __first;
+    while (++__p != __last)
+    {
+        if (__pred(*__p))
+        {
+            _IterOps<_AlgPolicy>::iter_swap(__first, __p);
+            ++__first;
+        }
+    }
+    return std::make_pair(std::move(__first), std::move(__p));
+}
+
+template <class _Predicate, class _AlgPolicy, class _BidirectionalIterator, class _Sentinel>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_BidirectionalIterator, _BidirectionalIterator>
+__partition_impl(_BidirectionalIterator __first, _Sentinel __sentinel, _Predicate __pred,
+            bidirectional_iterator_tag)
+{
+    _BidirectionalIterator __original_last = _IterOps<_AlgPolicy>::next(__first, __sentinel);
+    _BidirectionalIterator __last = __original_last;
+
+    while (true)
+    {
+        while (true)
+        {
+            if (__first == __last)
+                return std::make_pair(std::move(__first), std::move(__original_last));
+            if (!__pred(*__first))
+                break;
+            ++__first;
+        }
+        do
+        {
+            if (__first == --__last)
+                return std::make_pair(std::move(__first), std::move(__original_last));
+        } while (!__pred(*__last));
+        _IterOps<_AlgPolicy>::iter_swap(__first, __last);
+        ++__first;
+    }
+}
+
+template <class _AlgPolicy, class _ForwardIterator, class _Sentinel, class _Predicate, class _IterCategory>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+pair<_ForwardIterator, _ForwardIterator> __partition(
+    _ForwardIterator __first, _Sentinel __last, _Predicate&& __pred, _IterCategory __iter_category) {
+  return std::__partition_impl<__remove_cvref_t<_Predicate>&, _AlgPolicy>(
+      std::move(__first), std::move(__last), __pred, __iter_category);
+}
+
+template <class _ForwardIterator, class _Predicate>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+_ForwardIterator
+partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+  using _IterCategory = typename iterator_traits<_ForwardIterator>::iterator_category;
+  auto __result = std::__partition<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __pred, _IterCategory());
+  return __result.first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PARTITION_H

third_party/libcxx/__algorithm/partition_copy.h

@@ -0,0 +1,47 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PARTITION_COPY_H
+#define _LIBCPP___ALGORITHM_PARTITION_COPY_H
+
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _InputIterator, class _OutputIterator1,
+          class _OutputIterator2, class _Predicate>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_OutputIterator1, _OutputIterator2>
+partition_copy(_InputIterator __first, _InputIterator __last,
+               _OutputIterator1 __out_true, _OutputIterator2 __out_false,
+               _Predicate __pred)
+{
+    for (; __first != __last; ++__first)
+    {
+        if (__pred(*__first))
+        {
+            *__out_true = *__first;
+            ++__out_true;
+        }
+        else
+        {
+            *__out_false = *__first;
+            ++__out_false;
+        }
+    }
+    return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PARTITION_COPY_H

third_party/libcxx/__algorithm/partition_point.h

@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PARTITION_POINT_H
+#define _LIBCPP___ALGORITHM_PARTITION_POINT_H
+
+#include <__algorithm/half_positive.h>
+#include <__config>
+#include <__iterator/advance.h>
+#include <__iterator/distance.h>
+#include <__iterator/iterator_traits.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template<class _ForwardIterator, class _Predicate>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
+partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
+{
+    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
+    difference_type __len = _VSTD::distance(__first, __last);
+    while (__len != 0)
+    {
+        difference_type __l2 = _VSTD::__half_positive(__len);
+        _ForwardIterator __m = __first;
+        _VSTD::advance(__m, __l2);
+        if (__pred(*__m))
+        {
+            __first = ++__m;
+            __len -= __l2 + 1;
+        }
+        else
+            __len = __l2;
+    }
+    return __first;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PARTITION_POINT_H

third_party/libcxx/__algorithm/pop_heap.h

@@ -0,0 +1,74 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_POP_HEAP_H
+#define _LIBCPP___ALGORITHM_POP_HEAP_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/push_heap.h>
+#include <__algorithm/sift_down.h>
+#include <__assert>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_copy_assignable.h>
+#include <__type_traits/is_copy_constructible.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+void __pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp,
+    typename iterator_traits<_RandomAccessIterator>::difference_type __len) {
+  _LIBCPP_ASSERT(__len > 0, "The heap given to pop_heap must be non-empty");
+
+  __comp_ref_type<_Compare> __comp_ref = __comp;
+
+  using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
+  if (__len > 1) {
+    value_type __top = _IterOps<_AlgPolicy>::__iter_move(__first);  // create a hole at __first
+    _RandomAccessIterator __hole = std::__floyd_sift_down<_AlgPolicy>(__first, __comp_ref, __len);
+    --__last;
+
+    if (__hole == __last) {
+      *__hole = std::move(__top);
+    } else {
+      *__hole = _IterOps<_AlgPolicy>::__iter_move(__last);
+      ++__hole;
+      *__last = std::move(__top);
+      std::__sift_up<_AlgPolicy>(__first, __hole, __comp_ref, __hole - __first);
+    }
+  }
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
+  static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
+  static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
+
+  typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;
+  std::__pop_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp, __len);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
+  std::pop_heap(std::move(__first), std::move(__last),
+      __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_POP_HEAP_H

third_party/libcxx/__algorithm/prev_permutation.h

@@ -0,0 +1,79 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PREV_PERMUTATION_H
+#define _LIBCPP___ALGORITHM_PREV_PERMUTATION_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/reverse.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _Compare, class _BidirectionalIterator, class _Sentinel>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+pair<_BidirectionalIterator, bool>
+__prev_permutation(_BidirectionalIterator __first, _Sentinel __last, _Compare&& __comp)
+{
+    using _Result = pair<_BidirectionalIterator, bool>;
+
+    _BidirectionalIterator __last_iter = _IterOps<_AlgPolicy>::next(__first, __last);
+    _BidirectionalIterator __i = __last_iter;
+    if (__first == __last || __first == --__i)
+        return _Result(std::move(__last_iter), false);
+
+    while (true)
+    {
+        _BidirectionalIterator __ip1 = __i;
+        if (__comp(*__ip1, *--__i))
+        {
+            _BidirectionalIterator __j = __last_iter;
+            while (!__comp(*--__j, *__i))
+                ;
+            _IterOps<_AlgPolicy>::iter_swap(__i, __j);
+            std::__reverse<_AlgPolicy>(__ip1, __last_iter);
+            return _Result(std::move(__last_iter), true);
+        }
+        if (__i == __first)
+        {
+            std::__reverse<_AlgPolicy>(__first, __last_iter);
+            return _Result(std::move(__last_iter), false);
+        }
+    }
+}
+
+template <class _BidirectionalIterator, class _Compare>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
+{
+  return std::__prev_permutation<_ClassicAlgPolicy>(
+      std::move(__first), std::move(__last), static_cast<__comp_ref_type<_Compare> >(__comp)).second;
+}
+
+template <class _BidirectionalIterator>
+inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
+bool
+prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
+{
+    return _VSTD::prev_permutation(__first, __last,
+                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PREV_PERMUTATION_H

third_party/libcxx/__algorithm/pstl_any_all_none_of.h

@@ -0,0 +1,95 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_ANY_ALL_NONE_OF_H
+#define _LIBCPP___ALGORITHM_PSTL_ANY_ALL_NONE_OF_H
+
+#include <__algorithm/pstl_find.h>
+#include <__algorithm/pstl_frontend_dispatch.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__type_traits/remove_cvref.h>
+#include <__utility/terminate_on_exception.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class>
+void __pstl_any_of(); // declaration needed for the frontend dispatch below
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Predicate,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI bool
+any_of(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
+  return std::__pstl_frontend_dispatch(
+      _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_any_of),
+      [&](_ForwardIterator __g_first, _ForwardIterator __g_last, _Predicate __g_pred) {
+        return std::find_if(__policy, __g_first, __g_last, __g_pred) != __g_last;
+      },
+      std::move(__first),
+      std::move(__last),
+      std::move(__pred));
+}
+
+template <class>
+void __pstl_all_of(); // declaration needed for the frontend dispatch below
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Pred,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI bool
+all_of(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Pred __pred) {
+  return std::__pstl_frontend_dispatch(
+      _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_all_of),
+      [&](_ForwardIterator __g_first, _ForwardIterator __g_last, _Pred __g_pred) {
+        return !std::any_of(__policy, __g_first, __g_last, [&](__iter_reference<_ForwardIterator> __value) {
+          return !__g_pred(__value);
+        });
+      },
+      std::move(__first),
+      std::move(__last),
+      std::move(__pred));
+}
+
+template <class>
+void __pstl_none_of(); // declaration needed for the frontend dispatch below
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Pred,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI bool
+none_of(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Pred __pred) {
+  return std::__pstl_frontend_dispatch(
+      _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_none_of),
+      [&](_ForwardIterator __g_first, _ForwardIterator __g_last, _Pred __g_pred) {
+        return !std::any_of(__policy, __g_first, __g_last, __g_pred);
+      },
+      std::move(__first),
+      std::move(__last),
+      std::move(__pred));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_ANY_ALL_NONE_OF_H

third_party/libcxx/__algorithm/pstl_backend.h

@@ -0,0 +1,125 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKEND_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKEND_H
+
+#include <__algorithm/pstl_backends/cpu_backend.h>
+#include <__config>
+#include <execution>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+/*
+TODO: Documentation of how backends work
+
+A PSTL parallel backend is a tag type to which the following functions are associated, at minimum:
+
+  template <class _ExecutionPolicy, class _Iterator, class _Func>
+  void __pstl_for_each(_Backend, _ExecutionPolicy&&, _Iterator __first, _Iterator __last, _Func __f);
+
+  template <class _ExecutionPolicy, class _Iterator, class _Predicate>
+  _Iterator __pstl_find_if(_Backend, _Iterator __first, _Iterator __last, _Predicate __pred);
+
+  template <class _ExecutionPolicy, class _InIterator, class _OutIterator, class _UnaryOperation>
+  _OutIterator __pstl_transform(_InIterator __first, _InIterator __last, _OutIterator __result, _UnaryOperation __op);
+
+  template <class _ExecutionPolicy, class _InIterator1, class _InIterator2, class _OutIterator, class _BinaryOperation>
+  _OutIterator __pstl_transform(_InIterator1 __first1,
+                                _InIterator1 __last1,
+                                _InIterator2 __first2,
+                                _OutIterator __result,
+                                _BinaryOperation __op);
+
+// TODO: Complete this list
+
+The following functions are optional but can be provided. If provided, they are used by the corresponding
+algorithms, otherwise they are implemented in terms of other algorithms. If none of the optional algorithms are
+implemented, all the algorithms will eventually forward to the basis algorithms listed above:
+
+  template <class _ExecutionPolicy, class _Iterator, class _Size, class _Func>
+  void __pstl_for_each_n(_Backend, _Iterator __first, _Size __n, _Func __f);
+
+  template <class _ExecutionPolicy, class _Iterator, class _Predicate>
+  bool __pstl_any_of(_Backend, _Iterator __first, _iterator __last, _Predicate __pred);
+
+  template <class _ExecutionPolicy, class _Iterator, class _Predicate>
+  bool __pstl_all_of(_Backend, _Iterator __first, _iterator __last, _Predicate __pred);
+
+  template <class _ExecutionPolicy, class _Iterator, class _Predicate>
+  bool __pstl_none_of(_Backend, _Iterator __first, _iterator __last, _Predicate __pred);
+
+  template <class _ExecutionPolicy, class _Iterator, class _Tp>
+  _Iterator __pstl_find(_Backend, _Iterator __first, _Iterator __last, const _Tp& __value);
+
+  template <class _ExecutionPolicy, class _Iterator, class _Predicate>
+  _Iterator __pstl_find_if_not(_Backend, _Iterator __first, _Iterator __last, _Predicate __pred);
+
+  template <class _ExecutionPolicy, class _Iterator, class _Tp>
+  void __pstl_fill(_Backend, _Iterator __first, _Iterator __last, const _Tp& __value);
+
+  template <class _ExecutionPolicy, class _Iterator, class _SizeT, class _Tp>
+  void __pstl_fill_n(_Backend, _Iterator __first, _SizeT __n, const _Tp& __value);
+
+  template <class _ExecutionPolicy, class _terator1, class _Iterator2, class _OutIterator, class _Comp>
+  _OutIterator __pstl_merge(_Backend,
+                            _Iterator1 __first1,
+                            _Iterator1 __last1,
+                            _Iterator2 __first2,
+                            _Iterator2 __last2,
+                            _OutIterator __result,
+                            _Comp __comp);
+
+// TODO: Complete this list
+
+*/
+
+template <class _ExecutionPolicy>
+struct __select_backend;
+
+template <>
+struct __select_backend<std::execution::sequenced_policy> {
+  using type = __cpu_backend_tag;
+};
+
+#  if _LIBCPP_STD_VER >= 20
+template <>
+struct __select_backend<std::execution::unsequenced_policy> {
+  using type = __cpu_backend_tag;
+};
+#  endif
+
+#  if defined(_LIBCPP_PSTL_CPU_BACKEND_SERIAL) || defined(_LIBCPP_PSTL_CPU_BACKEND_THREAD)
+template <>
+struct __select_backend<std::execution::parallel_policy> {
+  using type = __cpu_backend_tag;
+};
+
+template <>
+struct __select_backend<std::execution::parallel_unsequenced_policy> {
+  using type = __cpu_backend_tag;
+};
+
+#  else
+
+// ...New vendors can add parallel backends here...
+
+#    error "Invalid choice of a PSTL parallel backend"
+#  endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKEND_H

third_party/libcxx/__algorithm/pstl_backends/cpu_backend.h

@@ -0,0 +1,47 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKEND_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKEND_H
+
+#include <__config>
+
+/*
+
+  // _Functor takes a subrange for [__first, __last) that should be executed in serial
+  template <class _RandomAccessIterator, class _Functor>
+  void __parallel_for(_RandomAccessIterator __first, _RandomAccessIterator __last, _Functor __func);
+
+  // Cancel the execution of other jobs - they aren't needed anymore
+  void __cancel_execution();
+
+  template <class _RandomAccessIterator1,
+            class _RandomAccessIterator2,
+            class _RandomAccessIterator3,
+            class _Compare,
+            class _LeafMerge>
+  void __parallel_merge(
+      _RandomAccessIterator1 __first1,
+      _RandomAccessIterator1 __last1,
+      _RandomAccessIterator2 __first2,
+      _RandomAccessIterator2 __last2,
+      _RandomAccessIterator3 __outit,
+      _Compare __comp,
+      _LeafMerge __leaf_merge);
+
+  TODO: Document the parallel backend
+*/
+
+#include <__algorithm/pstl_backends/cpu_backends/any_of.h>
+#include <__algorithm/pstl_backends/cpu_backends/fill.h>
+#include <__algorithm/pstl_backends/cpu_backends/find_if.h>
+#include <__algorithm/pstl_backends/cpu_backends/for_each.h>
+#include <__algorithm/pstl_backends/cpu_backends/merge.h>
+#include <__algorithm/pstl_backends/cpu_backends/transform.h>
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKEND_H

third_party/libcxx/__algorithm/pstl_backends/cpu_backends/any_of.h

@@ -0,0 +1,90 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKEND_ANY_OF_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKEND_ANY_OF_H
+
+#include <__algorithm/any_of.h>
+#include <__algorithm/find_if.h>
+#include <__algorithm/pstl_backends/cpu_backends/backend.h>
+#include <__atomic/atomic.h>
+#include <__atomic/memory_order.h>
+#include <__config>
+#include <__functional/operations.h>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__utility/pair.h>
+#include <__utility/terminate_on_exception.h>
+#include <cstdint>
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Index, class _Brick>
+_LIBCPP_HIDE_FROM_ABI bool __parallel_or(_Index __first, _Index __last, _Brick __f) {
+  std::atomic<bool> __found(false);
+  __par_backend::__parallel_for(__first, __last, [__f, &__found](_Index __i, _Index __j) {
+    if (!__found.load(std::memory_order_relaxed) && __f(__i, __j)) {
+      __found.store(true, std::memory_order_relaxed);
+      __par_backend::__cancel_execution();
+    }
+  });
+  return __found;
+}
+
+// TODO: check whether __simd_first() can be used here
+template <class _Index, class _DifferenceType, class _Pred>
+_LIBCPP_HIDE_FROM_ABI bool __simd_or(_Index __first, _DifferenceType __n, _Pred __pred) noexcept {
+  _DifferenceType __block_size = 4 < __n ? 4 : __n;
+  const _Index __last          = __first + __n;
+  while (__last != __first) {
+    int32_t __flag = 1;
+    _PSTL_PRAGMA_SIMD_REDUCTION(& : __flag)
+    for (_DifferenceType __i = 0; __i < __block_size; ++__i)
+      if (__pred(*(__first + __i)))
+        __flag = 0;
+    if (!__flag)
+      return true;
+
+    __first += __block_size;
+    if (__last - __first >= __block_size << 1) {
+      // Double the block _Size.  Any unnecessary iterations can be amortized against work done so far.
+      __block_size <<= 1;
+    } else {
+      __block_size = __last - __first;
+    }
+  }
+  return false;
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+_LIBCPP_HIDE_FROM_ABI bool
+__pstl_any_of(__cpu_backend_tag, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
+  if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
+                __has_random_access_iterator_category<_ForwardIterator>::value) {
+    return std::__terminate_on_exception([&] {
+      return std::__parallel_or(
+          __first, __last, [&__pred](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
+            return std::__pstl_any_of<__remove_parallel_policy_t<_ExecutionPolicy>>(
+                __cpu_backend_tag{}, __brick_first, __brick_last, __pred);
+          });
+    });
+  } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
+                       __has_random_access_iterator_category<_ForwardIterator>::value) {
+    return std::__simd_or(__first, __last - __first, __pred);
+  } else {
+    return std::any_of(__first, __last, __pred);
+  }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKEND_ANY_OF_H

third_party/libcxx/__algorithm/pstl_backends/cpu_backends/backend.h

@@ -0,0 +1,32 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKEND_BACKEND_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKEND_BACKEND_H
+
+#include <__config>
+
+#if defined(_LIBCPP_PSTL_CPU_BACKEND_SERIAL)
+#  include <__algorithm/pstl_backends/cpu_backends/serial.h>
+#elif defined(_LIBCPP_PSTL_CPU_BACKEND_THREAD)
+#  include <__algorithm/pstl_backends/cpu_backends/thread.h>
+#else
+#  error "Invalid CPU backend choice"
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+struct __cpu_backend_tag {};
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKEND_BACKEND_H

third_party/libcxx/__algorithm/pstl_backends/cpu_backends/fill.h

@@ -0,0 +1,60 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_FILL_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_FILL_H
+
+#include <__algorithm/fill.h>
+#include <__algorithm/pstl_backends/cpu_backends/backend.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__utility/terminate_on_exception.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Index, class _DifferenceType, class _Tp>
+_LIBCPP_HIDE_FROM_ABI _Index __simd_fill_n(_Index __first, _DifferenceType __n, const _Tp& __value) noexcept {
+  _PSTL_USE_NONTEMPORAL_STORES_IF_ALLOWED
+  _PSTL_PRAGMA_SIMD
+  for (_DifferenceType __i = 0; __i < __n; ++__i)
+    __first[__i] = __value;
+  return __first + __n;
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Tp>
+_LIBCPP_HIDE_FROM_ABI void
+__pstl_fill(__cpu_backend_tag, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
+  if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
+                __has_random_access_iterator_category<_ForwardIterator>::value) {
+    std::__terminate_on_exception([&] {
+      __par_backend::__parallel_for(
+          __first, __last, [&__value](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
+            std::__pstl_fill<__remove_parallel_policy_t<_ExecutionPolicy>>(
+                __cpu_backend_tag{}, __brick_first, __brick_last, __value);
+          });
+    });
+  } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
+                       __has_random_access_iterator_category<_ForwardIterator>::value) {
+    std::__simd_fill_n(__first, __last - __first, __value);
+  } else {
+    std::fill(__first, __last, __value);
+  }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_FILL_H

third_party/libcxx/__algorithm/pstl_backends/cpu_backends/find_if.h

@@ -0,0 +1,125 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_FIND_IF_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_FIND_IF_H
+
+#include <__algorithm/find_if.h>
+#include <__algorithm/pstl_backends/cpu_backends/backend.h>
+#include <__atomic/atomic.h>
+#include <__config>
+#include <__functional/operations.h>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__utility/pair.h>
+#include <__utility/terminate_on_exception.h>
+#include <cstddef>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Index, class _Brick, class _Compare>
+_LIBCPP_HIDE_FROM_ABI _Index
+__parallel_find(_Index __first, _Index __last, _Brick __f, _Compare __comp, bool __b_first) {
+  typedef typename std::iterator_traits<_Index>::difference_type _DifferenceType;
+  const _DifferenceType __n      = __last - __first;
+  _DifferenceType __initial_dist = __b_first ? __n : -1;
+  std::atomic<_DifferenceType> __extremum(__initial_dist);
+  // TODO: find out what is better here: parallel_for or parallel_reduce
+  __par_backend::__parallel_for(__first, __last, [__comp, __f, __first, &__extremum](_Index __i, _Index __j) {
+    // See "Reducing Contention Through Priority Updates", PPoPP '13, for discussion of
+    // why using a shared variable scales fairly well in this situation.
+    if (__comp(__i - __first, __extremum)) {
+      _Index __res = __f(__i, __j);
+      // If not '__last' returned then we found what we want so put this to extremum
+      if (__res != __j) {
+        const _DifferenceType __k = __res - __first;
+        for (_DifferenceType __old = __extremum; __comp(__k, __old); __old = __extremum) {
+          __extremum.compare_exchange_weak(__old, __k);
+        }
+      }
+    }
+  });
+  return __extremum != __initial_dist ? __first + __extremum : __last;
+}
+
+const std::size_t __lane_size = 64;
+
+template <class _Index, class _DifferenceType, class _Compare>
+_LIBCPP_HIDE_FROM_ABI _Index
+__simd_first(_Index __first, _DifferenceType __begin, _DifferenceType __end, _Compare __comp) noexcept {
+  // Experiments show good block sizes like this
+  const _DifferenceType __block_size                        = 8;
+  alignas(__lane_size) _DifferenceType __lane[__block_size] = {0};
+  while (__end - __begin >= __block_size) {
+    _DifferenceType __found = 0;
+    _PSTL_PRAGMA_SIMD_REDUCTION(| : __found) for (_DifferenceType __i = __begin; __i < __begin + __block_size; ++__i) {
+      const _DifferenceType __t = __comp(__first, __i);
+      __lane[__i - __begin]     = __t;
+      __found |= __t;
+    }
+    if (__found) {
+      _DifferenceType __i;
+      // This will vectorize
+      for (__i = 0; __i < __block_size; ++__i) {
+        if (__lane[__i]) {
+          break;
+        }
+      }
+      return __first + __begin + __i;
+    }
+    __begin += __block_size;
+  }
+
+  // Keep remainder scalar
+  while (__begin != __end) {
+    if (__comp(__first, __begin)) {
+      return __first + __begin;
+    }
+    ++__begin;
+  }
+  return __first + __end;
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Predicate>
+_LIBCPP_HIDE_FROM_ABI _ForwardIterator
+__pstl_find_if(__cpu_backend_tag, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
+  if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
+                __has_random_access_iterator_category<_ForwardIterator>::value) {
+    return std::__terminate_on_exception([&] {
+      return std::__parallel_find(
+          __first,
+          __last,
+          [&__pred](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
+            return std::__pstl_find_if<__remove_parallel_policy_t<_ExecutionPolicy>>(
+                __cpu_backend_tag{}, __brick_first, __brick_last, __pred);
+          },
+          less<>{},
+          true);
+    });
+  } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
+                       __has_random_access_iterator_category<_ForwardIterator>::value) {
+    using __diff_t = __iter_diff_t<_ForwardIterator>;
+    return std::__simd_first(__first, __diff_t(0), __last - __first, [&__pred](_ForwardIterator __iter, __diff_t __i) {
+      return __pred(__iter[__i]);
+    });
+  } else {
+    return std::find_if(__first, __last, __pred);
+  }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_FIND_IF_H

third_party/libcxx/__algorithm/pstl_backends/cpu_backends/for_each.h

@@ -0,0 +1,60 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKNEDS_FOR_EACH_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKNEDS_FOR_EACH_H
+
+#include <__algorithm/for_each.h>
+#include <__algorithm/pstl_backends/cpu_backends/backend.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__utility/terminate_on_exception.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Iterator, class _DifferenceType, class _Function>
+_LIBCPP_HIDE_FROM_ABI _Iterator __simd_walk_1(_Iterator __first, _DifferenceType __n, _Function __f) noexcept {
+  _PSTL_PRAGMA_SIMD
+  for (_DifferenceType __i = 0; __i < __n; ++__i)
+    __f(__first[__i]);
+
+  return __first + __n;
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _Functor>
+_LIBCPP_HIDE_FROM_ABI void
+__pstl_for_each(__cpu_backend_tag, _ForwardIterator __first, _ForwardIterator __last, _Functor __func) {
+  if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
+                __has_random_access_iterator_category<_ForwardIterator>::value) {
+    std::__terminate_on_exception([&] {
+      std::__par_backend::__parallel_for(
+          __first, __last, [__func](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
+            std::__pstl_for_each<__remove_parallel_policy_t<_ExecutionPolicy>>(
+                __cpu_backend_tag{}, __brick_first, __brick_last, __func);
+          });
+    });
+  } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
+                       __has_random_access_iterator_category<_ForwardIterator>::value) {
+    std::__simd_walk_1(__first, __last - __first, __func);
+  } else {
+    std::for_each(__first, __last, __func);
+  }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKNEDS_FOR_EACH_H

third_party/libcxx/__algorithm/pstl_backends/cpu_backends/merge.h

@@ -0,0 +1,79 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_MERGE_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_MERGE_H
+
+#include <__algorithm/merge.h>
+#include <__algorithm/pstl_backends/cpu_backends/backend.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__utility/move.h>
+#include <__utility/terminate_on_exception.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator1,
+          class _ForwardIterator2,
+          class _ForwardOutIterator,
+          class _Comp>
+_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator __pstl_merge(
+    __cpu_backend_tag,
+    _ForwardIterator1 __first1,
+    _ForwardIterator1 __last1,
+    _ForwardIterator2 __first2,
+    _ForwardIterator2 __last2,
+    _ForwardOutIterator __result,
+    _Comp __comp) {
+  if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
+                __has_random_access_iterator_category<_ForwardIterator1>::value &&
+                __has_random_access_iterator_category<_ForwardIterator2>::value &&
+                __has_random_access_iterator_category<_ForwardOutIterator>::value) {
+    return std::__terminate_on_exception([&] {
+      __par_backend::__parallel_merge(
+          __first1,
+          __last1,
+          __first2,
+          __last2,
+          __result,
+          __comp,
+          [](_ForwardIterator1 __g_first1,
+             _ForwardIterator1 __g_last1,
+             _ForwardIterator2 __g_first2,
+             _ForwardIterator2 __g_last2,
+             _ForwardOutIterator __g_result,
+             _Comp __g_comp) {
+            return std::__pstl_merge<__remove_parallel_policy_t<_ExecutionPolicy>>(
+                __cpu_backend_tag{},
+                std::move(__g_first1),
+                std::move(__g_last1),
+                std::move(__g_first2),
+                std::move(__g_last2),
+                std::move(__g_result),
+                std::move(__g_comp));
+          });
+      return __result + (__last1 - __first1) + (__last2 - __first2);
+    });
+  } else {
+    return std::merge(__first1, __last1, __first2, __last2, __result, __comp);
+  }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_MERGE_H

third_party/libcxx/__algorithm/pstl_backends/cpu_backends/serial.h

@@ -0,0 +1,58 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_SERIAL_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_SERIAL_H
+
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace __par_backend {
+inline namespace __serial_cpu_backend {
+
+template <class _RandomAccessIterator, class _Fp>
+_LIBCPP_HIDE_FROM_ABI void __parallel_for(_RandomAccessIterator __first, _RandomAccessIterator __last, _Fp __f) {
+  __f(__first, __last);
+}
+
+_LIBCPP_HIDE_FROM_ABI inline void __cancel_execution() {}
+
+template <class _RandomAccessIterator1,
+          class _RandomAccessIterator2,
+          class _RandomAccessIterator3,
+          class _Compare,
+          class _LeafMerge>
+_LIBCPP_HIDE_FROM_ABI void __parallel_merge(
+    _RandomAccessIterator1 __first1,
+    _RandomAccessIterator1 __last1,
+    _RandomAccessIterator2 __first2,
+    _RandomAccessIterator2 __last2,
+    _RandomAccessIterator3 __outit,
+    _Compare __comp,
+    _LeafMerge __leaf_merge) {
+  __leaf_merge(__first1, __last1, __first2, __last2, __outit, __comp);
+}
+
+// TODO: Complete this list
+
+} // namespace __serial_cpu_backend
+} // namespace __par_backend
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_SERIAL_H

third_party/libcxx/__algorithm/pstl_backends/cpu_backends/thread.h

@@ -0,0 +1,59 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_THREAD_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_THREAD_H
+
+#include <__assert>
+#include <__config>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+// This backend implementation is for testing purposes only and not meant for production use. This will be replaced
+// by a proper implementation once the PSTL implementation is somewhat stable.
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace __par_backend {
+inline namespace __thread_cpu_backend {
+
+template <class _RandomAccessIterator, class _Fp>
+_LIBCPP_HIDE_FROM_ABI void __parallel_for(_RandomAccessIterator __first, _RandomAccessIterator __last, _Fp __f) {
+  __f(__first, __last);
+}
+
+_LIBCPP_HIDE_FROM_ABI inline void __cancel_execution() {}
+
+template <class _RandomAccessIterator1,
+          class _RandomAccessIterator2,
+          class _RandomAccessIterator3,
+          class _Compare,
+          class _LeafMerge>
+_LIBCPP_HIDE_FROM_ABI void __parallel_merge(
+    _RandomAccessIterator1 __first1,
+    _RandomAccessIterator1 __last1,
+    _RandomAccessIterator2 __first2,
+    _RandomAccessIterator2 __last2,
+    _RandomAccessIterator3 __outit,
+    _Compare __comp,
+    _LeafMerge __leaf_merge) {
+  __leaf_merge(__first1, __last1, __first2, __last2, __outit, __comp);
+}
+
+} // namespace __thread_cpu_backend
+} // namespace __par_backend
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_THREAD_H

third_party/libcxx/__algorithm/pstl_backends/cpu_backends/transform.h

@@ -0,0 +1,132 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_TRANSFORM_H
+#define _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_TRANSFORM_H
+
+#include <__algorithm/pstl_backends/cpu_backends/backend.h>
+#include <__algorithm/transform.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__type_traits/remove_cvref.h>
+#include <__utility/terminate_on_exception.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _Iterator1, class _DifferenceType, class _Iterator2, class _Function>
+_LIBCPP_HIDE_FROM_ABI _Iterator2
+__simd_walk_2(_Iterator1 __first1, _DifferenceType __n, _Iterator2 __first2, _Function __f) noexcept {
+  _PSTL_PRAGMA_SIMD
+  for (_DifferenceType __i = 0; __i < __n; ++__i)
+    __f(__first1[__i], __first2[__i]);
+  return __first2 + __n;
+}
+
+template <class _ExecutionPolicy, class _ForwardIterator, class _ForwardOutIterator, class _UnaryOperation>
+_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator __pstl_transform(
+    __cpu_backend_tag,
+    _ForwardIterator __first,
+    _ForwardIterator __last,
+    _ForwardOutIterator __result,
+    _UnaryOperation __op) {
+  if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
+                __has_random_access_iterator_category<_ForwardIterator>::value &&
+                __has_random_access_iterator_category<_ForwardOutIterator>::value) {
+    std::__terminate_on_exception([&] {
+      std::__par_backend::__parallel_for(
+          __first, __last, [__op, __first, __result](_ForwardIterator __brick_first, _ForwardIterator __brick_last) {
+            return std::__pstl_transform<__remove_parallel_policy_t<_ExecutionPolicy>>(
+                __cpu_backend_tag{}, __brick_first, __brick_last, __result + (__brick_first - __first), __op);
+          });
+    });
+    return __result + (__last - __first);
+  } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
+                       __has_random_access_iterator_category<_ForwardIterator>::value &&
+                       __has_random_access_iterator_category<_ForwardOutIterator>::value) {
+    return std::__simd_walk_2(
+        __first,
+        __last - __first,
+        __result,
+        [&](__iter_reference<_ForwardIterator> __in_value, __iter_reference<_ForwardOutIterator> __out_value) {
+          __out_value = __op(__in_value);
+        });
+  } else {
+    return std::transform(__first, __last, __result, __op);
+  }
+}
+
+template <class _Iterator1, class _DifferenceType, class _Iterator2, class _Iterator3, class _Function>
+_LIBCPP_HIDE_FROM_ABI _Iterator3 __simd_walk_3(
+    _Iterator1 __first1, _DifferenceType __n, _Iterator2 __first2, _Iterator3 __first3, _Function __f) noexcept {
+  _PSTL_PRAGMA_SIMD
+  for (_DifferenceType __i = 0; __i < __n; ++__i)
+    __f(__first1[__i], __first2[__i], __first3[__i]);
+  return __first3 + __n;
+}
+template <class _ExecutionPolicy,
+          class _ForwardIterator1,
+          class _ForwardIterator2,
+          class _ForwardOutIterator,
+          class _BinaryOperation,
+          enable_if_t<is_execution_policy_v<__remove_cvref_t<_ExecutionPolicy>>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator __pstl_transform(
+    __cpu_backend_tag,
+    _ForwardIterator1 __first1,
+    _ForwardIterator1 __last1,
+    _ForwardIterator2 __first2,
+    _ForwardOutIterator __result,
+    _BinaryOperation __op) {
+  if constexpr (__is_parallel_execution_policy_v<_ExecutionPolicy> &&
+                __has_random_access_iterator_category<_ForwardIterator1>::value &&
+                __has_random_access_iterator_category<_ForwardIterator2>::value &&
+                __has_random_access_iterator_category<_ForwardOutIterator>::value) {
+    std::__terminate_on_exception([&] {
+      std::__par_backend::__parallel_for(
+          __first1,
+          __last1,
+          [__op, __first1, __first2, __result](_ForwardIterator1 __brick_first, _ForwardIterator1 __brick_last) {
+            return std::__pstl_transform<__remove_parallel_policy_t<_ExecutionPolicy>>(
+                __cpu_backend_tag{},
+                __brick_first,
+                __brick_last,
+                __first2 + (__brick_first - __first1),
+                __result + (__brick_first - __first1),
+                __op);
+          });
+    });
+    return __result + (__last1 - __first1);
+  } else if constexpr (__is_unsequenced_execution_policy_v<_ExecutionPolicy> &&
+                       __has_random_access_iterator_category<_ForwardIterator1>::value &&
+                       __has_random_access_iterator_category<_ForwardIterator2>::value &&
+                       __has_random_access_iterator_category<_ForwardOutIterator>::value) {
+    return std::__simd_walk_3(
+        __first1,
+        __last1 - __first1,
+        __first2,
+        __result,
+        [&](__iter_reference<_ForwardIterator1> __in1,
+            __iter_reference<_ForwardIterator2> __in2,
+            __iter_reference<_ForwardOutIterator> __out_value) { __out_value = __op(__in1, __in2); });
+  } else {
+    return std::transform(__first1, __last1, __first2, __result, __op);
+  }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_BACKENDS_CPU_BACKENDS_TRANSFORM_H

third_party/libcxx/__algorithm/pstl_copy.h

@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_COPY_H
+#define _LIBCPP___ALGORITHM_PSTL_COPY_H
+
+#include <__algorithm/copy_n.h>
+#include <__algorithm/pstl_transform.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_constant_evaluated.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__type_traits/is_trivially_copyable.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// TODO: Use the std::copy/move shenanigans to forward to std::memmove
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _ForwardOutIterator,
+          enable_if_t<is_execution_policy_v<__remove_cvref_t<_ExecutionPolicy>>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
+copy(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _ForwardOutIterator __result) {
+  return std::transform(__policy, __first, __last, __result, __identity());
+}
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _ForwardOutIterator,
+          class _Size,
+          enable_if_t<is_execution_policy_v<__remove_cvref_t<_ExecutionPolicy>>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
+copy_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __n, _ForwardOutIterator __result) {
+  if constexpr (__has_random_access_iterator_category<_ForwardIterator>::value)
+    return std::copy(__policy, __first, __first + __n, __result);
+  else
+    return std::copy_n(__first, __n, __result);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_COPY_H

third_party/libcxx/__algorithm/pstl_fill.h

@@ -0,0 +1,79 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_FILL_H
+#define _LIBCPP___ALGORITHM_PSTL_FILL_H
+
+#include <__algorithm/fill_n.h>
+#include <__algorithm/pstl_for_each.h>
+#include <__algorithm/pstl_frontend_dispatch.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__type_traits/remove_cvref.h>
+#include <__utility/terminate_on_exception.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class>
+void __pstl_fill(); // declaration needed for the frontend dispatch below
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Tp,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI void
+fill(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
+  std::__pstl_frontend_dispatch(
+      _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_fill),
+      [&](_ForwardIterator __g_first, _ForwardIterator __g_last, const _Tp& __g_value) {
+        std::for_each(__policy, __g_first, __g_last, [&](__iter_reference<_ForwardIterator> __element) {
+          __element = __g_value;
+        });
+      },
+      std::move(__first),
+      std::move(__last),
+      __value);
+}
+
+template <class>
+void __pstl_fill_n(); // declaration needed for the frontend dispatch below
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _SizeT,
+          class _Tp,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI void
+fill_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _SizeT __n, const _Tp& __value) {
+  std::__pstl_frontend_dispatch(
+      _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_fill_n),
+      [&](_ForwardIterator __g_first, _SizeT __g_n, const _Tp& __g_value) {
+        if constexpr (__has_random_access_iterator_category<_ForwardIterator>::value)
+          std::fill(__policy, __g_first, __g_first + __g_n, __g_value);
+        else
+          std::fill_n(__g_first, __g_n, __g_value);
+      },
+      std::move(__first),
+      __n,
+      __value);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_FILL_H

third_party/libcxx/__algorithm/pstl_find.h

@@ -0,0 +1,89 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_FIND_H
+#define _LIBCPP___ALGORITHM_PSTL_FIND_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/find.h>
+#include <__algorithm/pstl_backend.h>
+#include <__algorithm/pstl_frontend_dispatch.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__type_traits/remove_cvref.h>
+#include <__utility/terminate_on_exception.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Predicate,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _ForwardIterator
+find_if(_ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
+  using _Backend = typename __select_backend<_RawPolicy>::type;
+  return std::__pstl_find_if<_RawPolicy>(_Backend{}, std::move(__first), std::move(__last), std::move(__pred));
+}
+
+template <class>
+void __pstl_find_if_not();
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Predicate,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _ForwardIterator
+find_if_not(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
+  return std::__pstl_frontend_dispatch(
+      _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_find_if_not),
+      [&](_ForwardIterator __g_first, _ForwardIterator __g_last, _Predicate __g_pred) {
+        return std::find_if(__policy, __g_first, __g_last, [&](__iter_reference<_ForwardIterator> __value) {
+          return !__g_pred(__value);
+        });
+      },
+      std::move(__first),
+      std::move(__last),
+      std::move(__pred));
+}
+
+template <class>
+void __pstl_find();
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Tp,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _ForwardIterator
+find(_ExecutionPolicy&& __policy, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) {
+  return std::__pstl_frontend_dispatch(
+      _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_find),
+      [&](_ForwardIterator __g_first, _ForwardIterator __g_last, const _Tp& __g_value) {
+        return std::find_if(__policy, __g_first, __g_last, [&](__iter_reference<_ForwardIterator> __element) {
+          return __element == __g_value;
+        });
+      },
+      std::move(__first),
+      std::move(__last),
+      __value);
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_FIND_H

third_party/libcxx/__algorithm/pstl_for_each.h

@@ -0,0 +1,71 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_FOR_EACH_H
+#define _LIBCPP___ALGORITHM_PSTL_FOR_EACH_H
+
+#include <__algorithm/for_each.h>
+#include <__algorithm/for_each_n.h>
+#include <__algorithm/pstl_backend.h>
+#include <__algorithm/pstl_frontend_dispatch.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__type_traits/remove_cvref.h>
+#include <__type_traits/void_t.h>
+#include <__utility/terminate_on_exception.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Function,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI void
+for_each(_ExecutionPolicy&&, _ForwardIterator __first, _ForwardIterator __last, _Function __func) {
+  using _Backend = typename __select_backend<_RawPolicy>::type;
+  std::__pstl_for_each<_RawPolicy>(_Backend{}, std::move(__first), std::move(__last), std::move(__func));
+}
+
+template <class>
+void __pstl_for_each_n(); // declaration needed for the frontend dispatch below
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _Size,
+          class _Function,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI void
+for_each_n(_ExecutionPolicy&& __policy, _ForwardIterator __first, _Size __size, _Function __func) {
+  return std::__pstl_frontend_dispatch(
+      _LIBCPP_PSTL_CUSTOMIZATION_POINT(__pstl_for_each_n),
+      [&](_ForwardIterator __g_first, _Size __g_size, _Function __g_func) {
+        if constexpr (__has_random_access_iterator_category<_ForwardIterator>::value) {
+          std::for_each(__policy, std::move(__g_first), __g_first + __g_size, std::move(__g_func));
+        } else {
+          std::for_each_n(std::move(__g_first), __g_size, std::move(__g_func));
+        }
+      },
+      __first,
+      __size,
+      std::move(__func));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_FOR_EACH_H

third_party/libcxx/__algorithm/pstl_frontend_dispatch.h

@@ -0,0 +1,45 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_FRONTEND_DISPATCH
+#define _LIBCPP___ALGORITHM_PSTL_FRONTEND_DISPATCH
+
+#include <__config>
+#include <__type_traits/is_callable.h>
+#include <__utility/forward.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#  define _LIBCPP_PSTL_CUSTOMIZATION_POINT(name)                                                                       \
+    [](auto&&... __args) -> decltype(std::name<_RawPolicy>(typename __select_backend<_RawPolicy>::type{},              \
+                                                           std::forward<decltype(__args)>(__args)...)) {               \
+      return std::name<_RawPolicy>(                                                                                    \
+          typename __select_backend<_RawPolicy>::type{}, std::forward<decltype(__args)>(__args)...);                   \
+    }
+
+template <class _SpecializedImpl, class _GenericImpl, class... _Args>
+_LIBCPP_HIDE_FROM_ABI decltype(auto)
+__pstl_frontend_dispatch(_SpecializedImpl __specialized_impl, _GenericImpl __generic_impl, _Args&&... __args) {
+  if constexpr (__is_callable<_SpecializedImpl, _Args...>::value) {
+    return __specialized_impl(std::forward<_Args>(__args)...);
+  } else {
+    return __generic_impl(std::forward<_Args>(__args)...);
+  }
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_FRONTEND_DISPATCH

third_party/libcxx/__algorithm/pstl_merge.h

@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_MERGE_H
+#define _LIBCPP___ALGORITHM_PSTL_MERGE_H
+
+#include <__algorithm/pstl_backend.h>
+#include <__config>
+#include <__functional/operations.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__type_traits/remove_cvref.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator1,
+          class _ForwardIterator2,
+          class _ForwardOutIterator,
+          class _Comp                                         = std::less<>,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator
+merge(_ExecutionPolicy&&,
+      _ForwardIterator1 __first1,
+      _ForwardIterator1 __last1,
+      _ForwardIterator2 __first2,
+      _ForwardIterator2 __last2,
+      _ForwardOutIterator __result,
+      _Comp __comp = {}) {
+  using _Backend = typename __select_backend<_RawPolicy>::type;
+  return std::__pstl_merge<_RawPolicy>(
+      _Backend{},
+      std::move(__first1),
+      std::move(__last1),
+      std::move(__first2),
+      std::move(__last2),
+      std::move(__result),
+      std::move(__comp));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_MERGE_H

third_party/libcxx/__algorithm/pstl_transform.h

@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PSTL_TRANSFORM_H
+#define _LIBCPP___ALGORITHM_PSTL_TRANSFORM_H
+
+#include <__algorithm/pstl_backend.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_execution_policy.h>
+#include <__utility/terminate_on_exception.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator,
+          class _ForwardOutIterator,
+          class _UnaryOperation,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator transform(
+    _ExecutionPolicy&&,
+    _ForwardIterator __first,
+    _ForwardIterator __last,
+    _ForwardOutIterator __result,
+    _UnaryOperation __op) {
+  using _Backend = typename __select_backend<_RawPolicy>::type;
+  return std::__pstl_transform<_RawPolicy>(
+      _Backend{}, std::move(__first), std::move(__last), std::move(__result), std::move(__op));
+}
+
+template <class _ExecutionPolicy,
+          class _ForwardIterator1,
+          class _ForwardIterator2,
+          class _ForwardOutIterator,
+          class _BinaryOperation,
+          class _RawPolicy                                    = __remove_cvref_t<_ExecutionPolicy>,
+          enable_if_t<is_execution_policy_v<_RawPolicy>, int> = 0>
+_LIBCPP_HIDE_FROM_ABI _ForwardOutIterator transform(
+    _ExecutionPolicy&&,
+    _ForwardIterator1 __first1,
+    _ForwardIterator1 __last1,
+    _ForwardIterator2 __first2,
+    _ForwardOutIterator __result,
+    _BinaryOperation __op) {
+  using _Backend = typename __select_backend<_RawPolicy>::type;
+  return std::__pstl_transform<_RawPolicy>(
+      _Backend{}, std::move(__first1), std::move(__last1), std::move(__first2), std::move(__result), std::move(__op));
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_PSTL) && _LIBCPP_STD_VER >= 17
+
+#endif // _LIBCPP___ALGORITHM_PSTL_TRANSFORM_H

third_party/libcxx/__algorithm/push_heap.h

@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_PUSH_HEAP_H
+#define _LIBCPP___ALGORITHM_PUSH_HEAP_H
+
+#include <__algorithm/comp.h>
+#include <__algorithm/comp_ref_type.h>
+#include <__algorithm/iterator_operations.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__type_traits/is_copy_assignable.h>
+#include <__type_traits/is_copy_constructible.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+void __sift_up(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp,
+        typename iterator_traits<_RandomAccessIterator>::difference_type __len) {
+  using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
+
+  if (__len > 1) {
+    __len = (__len - 2) / 2;
+    _RandomAccessIterator __ptr = __first + __len;
+
+    if (__comp(*__ptr, *--__last)) {
+      value_type __t(_IterOps<_AlgPolicy>::__iter_move(__last));
+      do {
+        *__last = _IterOps<_AlgPolicy>::__iter_move(__ptr);
+        __last = __ptr;
+        if (__len == 0)
+          break;
+        __len = (__len - 1) / 2;
+        __ptr = __first + __len;
+      } while (__comp(*__ptr, __t));
+
+      *__last = std::move(__t);
+    }
+  }
+}
+
+template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
+void __push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) {
+  typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;
+  std::__sift_up<_AlgPolicy, __comp_ref_type<_Compare> >(std::move(__first), std::move(__last), __comp, __len);
+}
+
+template <class _RandomAccessIterator, class _Compare>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
+  static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
+  static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
+
+  std::__push_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
+}
+
+template <class _RandomAccessIterator>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
+void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
+  std::push_heap(std::move(__first), std::move(__last),
+      __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_PUSH_HEAP_H

third_party/libcxx/__algorithm/ranges_adjacent_find.h

@@ -0,0 +1,78 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_ADJACENT_FIND_H
+#define _LIBCPP___ALGORITHM_RANGES_ADJACENT_FIND_H
+
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/concepts.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __adjacent_find {
+struct __fn {
+
+  template <class _Iter, class _Sent, class _Proj, class _Pred>
+  _LIBCPP_HIDE_FROM_ABI constexpr static
+  _Iter __adjacent_find_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
+    if (__first == __last)
+      return __first;
+
+    auto __i = __first;
+    while (++__i != __last) {
+      if (std::invoke(__pred, std::invoke(__proj, *__first), std::invoke(__proj, *__i)))
+        return __first;
+      __first = __i;
+    }
+    return __i;
+  }
+
+  template <forward_iterator _Iter, sentinel_for<_Iter> _Sent,
+            class _Proj = identity,
+            indirect_binary_predicate<projected<_Iter, _Proj>, projected<_Iter, _Proj>> _Pred = ranges::equal_to>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
+  _Iter operator()(_Iter __first, _Sent __last, _Pred __pred = {}, _Proj __proj = {}) const {
+    return __adjacent_find_impl(std::move(__first), std::move(__last), __pred, __proj);
+  }
+
+  template <forward_range _Range,
+            class _Proj = identity,
+            indirect_binary_predicate<projected<iterator_t<_Range>, _Proj>,
+                                      projected<iterator_t<_Range>, _Proj>> _Pred = ranges::equal_to>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
+  borrowed_iterator_t<_Range> operator()(_Range&& __range, _Pred __pred = {}, _Proj __proj = {}) const {
+    return __adjacent_find_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
+  }
+};
+} // namespace __adjacent_find
+
+inline namespace __cpo {
+  inline constexpr auto adjacent_find = __adjacent_find::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#endif // _LIBCPP___ALGORITHM_RANGES_ADJACENT_FIND_H

third_party/libcxx/__algorithm/ranges_all_of.h

@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_ALL_OF_H
+#define _LIBCPP___ALGORITHM_RANGES_ALL_OF_H
+
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/concepts.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __all_of {
+struct __fn {
+
+  template <class _Iter, class _Sent, class _Proj, class _Pred>
+  _LIBCPP_HIDE_FROM_ABI constexpr static
+  bool __all_of_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
+    for (; __first != __last; ++__first) {
+      if (!std::invoke(__pred, std::invoke(__proj, *__first)))
+        return false;
+    }
+    return true;
+  }
+
+  template <input_iterator _Iter, sentinel_for<_Iter> _Sent, class _Proj = identity,
+            indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
+  bool operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) const {
+    return __all_of_impl(std::move(__first), std::move(__last), __pred, __proj);
+  }
+
+  template <input_range _Range, class _Proj = identity,
+            indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
+  bool operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const {
+    return __all_of_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
+  }
+};
+} // namespace __all_of
+
+inline namespace __cpo {
+  inline constexpr auto all_of = __all_of::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#endif // _LIBCPP___ALGORITHM_RANGES_ALL_OF_H

third_party/libcxx/__algorithm/ranges_any_of.h

@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_ANY_OF_H
+#define _LIBCPP___ALGORITHM_RANGES_ANY_OF_H
+
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/concepts.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __any_of {
+struct __fn {
+
+  template <class _Iter, class _Sent, class _Proj, class _Pred>
+  _LIBCPP_HIDE_FROM_ABI constexpr static
+  bool __any_of_impl(_Iter __first, _Sent __last, _Pred& __pred, _Proj& __proj) {
+    for (; __first != __last; ++__first) {
+      if (std::invoke(__pred, std::invoke(__proj, *__first)))
+        return true;
+    }
+    return false;
+  }
+
+  template <input_iterator _Iter, sentinel_for<_Iter> _Sent, class _Proj = identity,
+            indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
+  bool operator()(_Iter __first, _Sent __last, _Pred __pred = {}, _Proj __proj = {}) const {
+    return __any_of_impl(std::move(__first), std::move(__last), __pred, __proj);
+  }
+
+  template <input_range _Range, class _Proj = identity,
+            indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
+  bool operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) const {
+    return __any_of_impl(ranges::begin(__range), ranges::end(__range), __pred, __proj);
+  }
+};
+} // namespace __any_of
+
+inline namespace __cpo {
+  inline constexpr auto any_of = __any_of::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#endif // _LIBCPP___ALGORITHM_RANGES_ANY_OF_H

third_party/libcxx/__algorithm/ranges_binary_search.h

@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_BINARY_SEARCH_H
+#define _LIBCPP___ALGORITHM_RANGES_BINARY_SEARCH_H
+
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/lower_bound.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/concepts.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __binary_search {
+struct __fn {
+  template <forward_iterator _Iter, sentinel_for<_Iter> _Sent, class _Type, class _Proj = identity,
+            indirect_strict_weak_order<const _Type*, projected<_Iter, _Proj>> _Comp = ranges::less>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
+  bool operator()(_Iter __first, _Sent __last, const _Type& __value, _Comp __comp = {}, _Proj __proj = {}) const {
+    auto __ret = std::__lower_bound_impl<_RangeAlgPolicy>(__first, __last, __value, __comp, __proj);
+    return __ret != __last && !std::invoke(__comp, __value, std::invoke(__proj, *__ret));
+  }
+
+  template <forward_range _Range, class _Type, class _Proj = identity,
+            indirect_strict_weak_order<const _Type*, projected<iterator_t<_Range>, _Proj>> _Comp = ranges::less>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
+  bool operator()(_Range&& __r, const _Type& __value, _Comp __comp = {}, _Proj __proj = {}) const {
+    auto __first = ranges::begin(__r);
+    auto __last = ranges::end(__r);
+    auto __ret = std::__lower_bound_impl<_RangeAlgPolicy>(__first, __last, __value, __comp, __proj);
+    return __ret != __last && !std::invoke(__comp, __value, std::invoke(__proj, *__ret));
+  }
+};
+} // namespace __binary_search
+
+inline namespace __cpo {
+  inline constexpr auto binary_search = __binary_search::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#endif // _LIBCPP___ALGORITHM_RANGES_BINARY_SEARCH_H

third_party/libcxx/__algorithm/ranges_clamp.h

@@ -0,0 +1,65 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_CLAMP_H
+#define _LIBCPP___ALGORITHM_RANGES_CLAMP_H
+
+#include <__assert>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/concepts.h>
+#include <__iterator/projected.h>
+#include <__utility/forward.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __clamp {
+struct __fn {
+
+  template <class _Type,
+            class _Proj = identity,
+            indirect_strict_weak_order<projected<const _Type*, _Proj>> _Comp = ranges::less>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
+  const _Type& operator()(const _Type& __value,
+                          const _Type& __low,
+                          const _Type& __high,
+                          _Comp __comp = {},
+                          _Proj __proj = {}) const {
+    _LIBCPP_ASSERT(!bool(std::invoke(__comp, std::invoke(__proj, __high), std::invoke(__proj, __low))),
+                   "Bad bounds passed to std::ranges::clamp");
+
+    if (std::invoke(__comp, std::invoke(__proj, __value), std::invoke(__proj, __low)))
+      return __low;
+    else if (std::invoke(__comp, std::invoke(__proj, __high), std::invoke(__proj, __value)))
+      return __high;
+    else
+      return __value;
+  }
+
+};
+} // namespace __clamp
+
+inline namespace __cpo {
+  inline constexpr auto clamp = __clamp::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#endif // _LIBCPP___ALGORITHM_RANGES_CLAMP_H

third_party/libcxx/__algorithm/ranges_copy.h

@@ -0,0 +1,67 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_COPY_H
+#define _LIBCPP___ALGORITHM_RANGES_COPY_H
+
+#include <__algorithm/copy.h>
+#include <__algorithm/in_out_result.h>
+#include <__algorithm/iterator_operations.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__iterator/concepts.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+
+template <class _InIter, class _OutIter>
+using copy_result = in_out_result<_InIter, _OutIter>;
+
+namespace __copy {
+struct __fn {
+
+  template <input_iterator _InIter, sentinel_for<_InIter> _Sent, weakly_incrementable _OutIter>
+    requires indirectly_copyable<_InIter, _OutIter>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  copy_result<_InIter, _OutIter> operator()(_InIter __first, _Sent __last, _OutIter __result) const {
+    auto __ret = std::__copy<_RangeAlgPolicy>(std::move(__first), std::move(__last), std::move(__result));
+    return {std::move(__ret.first), std::move(__ret.second)};
+  }
+
+  template <input_range _Range, weakly_incrementable _OutIter>
+    requires indirectly_copyable<iterator_t<_Range>, _OutIter>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  copy_result<borrowed_iterator_t<_Range>, _OutIter> operator()(_Range&& __r, _OutIter __result) const {
+    auto __ret = std::__copy<_RangeAlgPolicy>(ranges::begin(__r), ranges::end(__r), std::move(__result));
+    return {std::move(__ret.first), std::move(__ret.second)};
+  }
+};
+} // namespace __copy
+
+inline namespace __cpo {
+  inline constexpr auto copy = __copy::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#endif // _LIBCPP___ALGORITHM_RANGES_COPY_H

third_party/libcxx/__algorithm/ranges_copy_backward.h

@@ -0,0 +1,65 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_COPY_BACKWARD_H
+#define _LIBCPP___ALGORITHM_RANGES_COPY_BACKWARD_H
+
+#include <__algorithm/copy_backward.h>
+#include <__algorithm/in_out_result.h>
+#include <__algorithm/iterator_operations.h>
+#include <__config>
+#include <__iterator/concepts.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+
+template<class _Ip, class _Op>
+using copy_backward_result = in_out_result<_Ip, _Op>;
+
+namespace __copy_backward {
+struct __fn {
+
+  template <bidirectional_iterator _InIter1, sentinel_for<_InIter1> _Sent1, bidirectional_iterator _InIter2>
+    requires indirectly_copyable<_InIter1, _InIter2>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  copy_backward_result<_InIter1, _InIter2> operator()(_InIter1 __first, _Sent1 __last, _InIter2 __result) const {
+    auto __ret = std::__copy_backward<_RangeAlgPolicy>(std::move(__first), std::move(__last), std::move(__result));
+    return {std::move(__ret.first), std::move(__ret.second)};
+  }
+
+  template <bidirectional_range _Range, bidirectional_iterator _Iter>
+    requires indirectly_copyable<iterator_t<_Range>, _Iter>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  copy_backward_result<borrowed_iterator_t<_Range>, _Iter> operator()(_Range&& __r, _Iter __result) const {
+    auto __ret = std::__copy_backward<_RangeAlgPolicy>(ranges::begin(__r), ranges::end(__r), std::move(__result));
+    return {std::move(__ret.first), std::move(__ret.second)};
+  }
+};
+} // namespace __copy_backward
+
+inline namespace __cpo {
+  inline constexpr auto copy_backward = __copy_backward::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#endif // _LIBCPP___ALGORITHM_RANGES_COPY_BACKWARD_H

third_party/libcxx/__algorithm/ranges_copy_if.h

@@ -0,0 +1,81 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_COPY_IF_H
+#define _LIBCPP___ALGORITHM_RANGES_COPY_IF_H
+
+#include <__algorithm/in_out_result.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__iterator/concepts.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER >= 20
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+
+template<class _Ip, class _Op>
+using copy_if_result = in_out_result<_Ip, _Op>;
+
+namespace __copy_if {
+struct __fn {
+
+  template <class _InIter, class _Sent, class _OutIter, class _Proj, class _Pred>
+  _LIBCPP_HIDE_FROM_ABI static constexpr
+  copy_if_result <_InIter, _OutIter>
+  __copy_if_impl(_InIter __first, _Sent __last, _OutIter __result, _Pred& __pred, _Proj& __proj) {
+    for (; __first != __last; ++__first) {
+      if (std::invoke(__pred, std::invoke(__proj, *__first))) {
+        *__result = *__first;
+        ++__result;
+      }
+    }
+    return {std::move(__first), std::move(__result)};
+  }
+
+  template <input_iterator _Iter, sentinel_for<_Iter> _Sent, weakly_incrementable _OutIter, class _Proj = identity,
+            indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
+    requires indirectly_copyable<_Iter, _OutIter>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  copy_if_result<_Iter, _OutIter>
+  operator()(_Iter __first, _Sent __last, _OutIter __result, _Pred __pred, _Proj __proj = {}) const {
+    return __copy_if_impl(std::move(__first), std::move(__last), std::move(__result), __pred, __proj);
+  }
+
+  template <input_range _Range, weakly_incrementable _OutIter, class _Proj = identity,
+            indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
+    requires indirectly_copyable<iterator_t<_Range>, _OutIter>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  copy_if_result<borrowed_iterator_t<_Range>, _OutIter>
+  operator()(_Range&& __r, _OutIter __result, _Pred __pred, _Proj __proj = {}) const {
+    return __copy_if_impl(ranges::begin(__r), ranges::end(__r), std::move(__result), __pred, __proj);
+  }
+};
+} // namespace __copy_if
+
+inline namespace __cpo {
+  inline constexpr auto copy_if = __copy_if::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 20
+
+#endif // _LIBCPP___ALGORITHM_RANGES_COPY_IF_H

third_party/libcxx/__algorithm/ranges_copy_n.h

@@ -0,0 +1,77 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_COPY_N_H
+#define _LIBCPP___ALGORITHM_RANGES_COPY_N_H
+
+#include <__algorithm/copy.h>
+#include <__algorithm/in_out_result.h>
+#include <__algorithm/iterator_operations.h>
+#include <__algorithm/ranges_copy.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__iterator/concepts.h>
+#include <__iterator/incrementable_traits.h>
+#include <__iterator/unreachable_sentinel.h>
+#include <__iterator/wrap_iter.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER >= 20
+
+namespace ranges {
+
+template <class _Ip, class _Op>
+using copy_n_result = in_out_result<_Ip, _Op>;
+
+namespace __copy_n {
+struct __fn {
+
+  template <class _InIter, class _DiffType, class _OutIter>
+  _LIBCPP_HIDE_FROM_ABI constexpr static
+  copy_n_result<_InIter, _OutIter> __go(_InIter __first, _DiffType __n, _OutIter __result) {
+    while (__n != 0) {
+      *__result = *__first;
+      ++__first;
+      ++__result;
+      --__n;
+    }
+    return {std::move(__first), std::move(__result)};
+  }
+
+  template <random_access_iterator _InIter, class _DiffType, random_access_iterator _OutIter>
+  _LIBCPP_HIDE_FROM_ABI constexpr static
+  copy_n_result<_InIter, _OutIter> __go(_InIter __first, _DiffType __n, _OutIter __result) {
+    auto __ret = std::__copy<_RangeAlgPolicy>(__first, __first + __n, __result);
+    return {__ret.first, __ret.second};
+  }
+
+  template <input_iterator _Ip, weakly_incrementable _Op>
+    requires indirectly_copyable<_Ip, _Op>
+  _LIBCPP_HIDE_FROM_ABI constexpr
+  copy_n_result<_Ip, _Op> operator()(_Ip __first, iter_difference_t<_Ip> __n, _Op __result) const {
+    return __go(std::move(__first), __n, std::move(__result));
+  }
+};
+} // namespace __copy_n
+
+inline namespace __cpo {
+  inline constexpr auto copy_n = __copy_n::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+#endif // _LIBCPP_STD_VER >= 20
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_RANGES_COPY_N_H