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MIPS: Loongson64: Clean up use of cc-ifversion 

This Makefile checks that GCC is 4.9 or newer, which is redundant after
commit 76ae847497 ("Documentation: raise minimum supported version of
GCC to 5.1"), so cc-option can be removed.

Clang does not support -march=loongson3a so it needs to continue to use
-march=mips64r2, which no longer needs cc-option because all supported
clang versions recognize this flag.

-march=loonson3a can be used unconditionally with GCC because the
minimum supported GCC version has been bumped past 4.9.0, which won't
have the bug mentioned in the comment. The _MIPS_ISA macro redefinition
can be removed at the same time for the same reason.

Suggested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Nathan Chancellor 2022-01-25 15:19:24 -07:00 committed by Thomas Bogendoerfer
parent a0b8cd5c22
commit 0e96ea5c3e
1 changed files with 3 additions and 18 deletions
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21
arch/mips/loongson64/Platform
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@ -5,24 +5,9 @@
cflags-$(CONFIG_CPU_LOONGSON64) += -Wa,--trap
#
# binutils from v2.25 on and gcc starting from v4.9.0 treat -march=loongson3a
# as MIPS64 R2; older versions as just R1. This leaves the possibility open
# that GCC might generate R2 code for -march=loongson3a which then is rejected
# by GAS. The cc-option can't probe for this behaviour so -march=loongson3a
# can't easily be used safely within the kbuild framework.
#
ifeq ($(call cc-ifversion, -ge, 0409, y), y)
ifeq ($(call ld-ifversion, -ge, 22500, y), y)
cflags-$(CONFIG_CPU_LOONGSON64) += \
$(call cc-option,-march=loongson3a -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64)
else
cflags-$(CONFIG_CPU_LOONGSON64) += \
$(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64)
endif
else
cflags-$(CONFIG_CPU_LOONGSON64) += \
$(call cc-option,-march=mips64r2,-mips64r2 -U_MIPS_ISA -D_MIPS_ISA=_MIPS_ISA_MIPS64)
ifdef CONFIG_CPU_LOONGSON64
cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a
cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2
endif
# Some -march= flags enable MMI instructions, and GCC complains about that