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a21151b9d8
Clang has -Wself-assign enabled by default under -Wall, which always gets -Werror'ed on this file, causing sync-compare-and-swap to be disabled by default. The generally-accepted way to spell "this value is intentionally unused," is casting it to `void`. This is accepted by both GCC and Clang with -Wall enabled: https://godbolt.org/z/qqZ9r3 Signed-off-by: George Burgess IV <gbiv@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Link: http://lkml.kernel.org/r/20200414195638.156123-1-gbiv@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
15 lines
286 B
C
15 lines
286 B
C
// SPDX-License-Identifier: GPL-2.0
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#include <stdint.h>
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volatile uint64_t x;
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int main(int argc, char *argv[])
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{
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uint64_t old, new = argc;
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(void)argv;
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do {
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old = __sync_val_compare_and_swap(&x, 0, 0);
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} while (!__sync_bool_compare_and_swap(&x, old, new));
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return old == new;
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}
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