From 3e063adfe931b2c0765d23b6c240d9d2924c664b Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Thu, 16 Sep 2021 11:40:16 -0700 Subject: [PATCH] x86/build: Do not add -falign flags unconditionally for clang clang does not support -falign-jumps and only recently gained support for -falign-loops. When one of the configuration options that adds these flags is enabled, clang warns and all cc-{disable-warning,option} that follow fail because -Werror gets added to test for the presence of this warning: clang-14: warning: optimization flag '-falign-jumps=0' is not supported [-Wignored-optimization-argument] To resolve this, add a couple of cc-option calls when building with clang; gcc has supported these options since 3.2 so there is no point in testing for their support. -falign-functions was implemented in clang-7, -falign-loops was implemented in clang-14, and -falign-jumps has not been implemented yet. Link: https://lore.kernel.org/r/YSQE2f5teuvKLkON@Ryzen-9-3900X.localdomain/ Link: https://lore.kernel.org/r/20210824022640.2170859-2-nathan@kernel.org/ Reported-by: kernel test robot Reviewed-by: Nick Desaulniers Acked-by: Borislav Petkov Signed-off-by: Nathan Chancellor Signed-off-by: Masahiro Yamada --- arch/x86/Makefile_32.cpu | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/Makefile_32.cpu b/arch/x86/Makefile_32.cpu index e7355f8b51c2b..94834c4b5e5ef 100644 --- a/arch/x86/Makefile_32.cpu +++ b/arch/x86/Makefile_32.cpu @@ -4,6 +4,12 @@ tune = $(call cc-option,-mtune=$(1),$(2)) +ifdef CONFIG_CC_IS_CLANG +align := -falign-functions=0 $(call cc-option,-falign-jumps=0) $(call cc-option,-falign-loops=0) +else +align := -falign-functions=0 -falign-jumps=0 -falign-loops=0 +endif + cflags-$(CONFIG_M486SX) += -march=i486 cflags-$(CONFIG_M486) += -march=i486 cflags-$(CONFIG_M586) += -march=i586 @@ -19,11 +25,11 @@ cflags-$(CONFIG_MK6) += -march=k6 # They make zero difference whatsosever to performance at this time. cflags-$(CONFIG_MK7) += -march=athlon cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8,-march=athlon) -cflags-$(CONFIG_MCRUSOE) += -march=i686 -falign-functions=0 -falign-jumps=0 -falign-loops=0 -cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) -falign-functions=0 -falign-jumps=0 -falign-loops=0 +cflags-$(CONFIG_MCRUSOE) += -march=i686 $(align) +cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) $(align) cflags-$(CONFIG_MWINCHIPC6) += $(call cc-option,-march=winchip-c6,-march=i586) cflags-$(CONFIG_MWINCHIP3D) += $(call cc-option,-march=winchip2,-march=i586) -cflags-$(CONFIG_MCYRIXIII) += $(call cc-option,-march=c3,-march=i486) -falign-functions=0 -falign-jumps=0 -falign-loops=0 +cflags-$(CONFIG_MCYRIXIII) += $(call cc-option,-march=c3,-march=i486) $(align) cflags-$(CONFIG_MVIAC3_2) += $(call cc-option,-march=c3-2,-march=i686) cflags-$(CONFIG_MVIAC7) += -march=i686 cflags-$(CONFIG_MCORE2) += -march=i686 $(call tune,core2) -- 2.39.5