x86/build: Do not add -falign flags unconditionally for clang
authorNathan Chancellor <nathan@kernel.org>
Thu, 16 Sep 2021 18:40:16 +0000 (11:40 -0700)
committerMasahiro Yamada <masahiroy@kernel.org>
Sun, 19 Sep 2021 01:35:53 +0000 (10:35 +0900)
commit7fa6a2746616c8de4c40b748c2bb0656e00624ff
tree2f8097a5df55574d5cf2ca5095cf352f73a6fd61
parent7c80144626db460bc3969027810a540741865fb1
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 <lkp@intel.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
arch/x86/Makefile_32.cpu