Re: [PATCH v2 2/2] MIPS: Loongson{2ef,64}: Wrap -mno-branch-likely with cc-option

From: Thomas Bogendoerfer
Date: Mon Feb 07 2022 - 12:49:04 EST


On Tue, Jan 25, 2022 at 03:19:25PM -0700, Nathan Chancellor wrote:
> This flag is not supported by clang, which results in a warning:
>
> clang-14: warning: argument unused during compilation: '-mno-branch-likely' [-Wunused-command-line-argument]
>
> This breaks cc-option, which adds -Werror to make this warning fatal and
> catch flags that are not supported.
>
> Wrap this flag in cc-option so that it does not cause cc-option to fail,
> which can cause randconfigs to be really noisy, due to warnings not
> getting disabled that should be.
>
> Additionally, move the cc-option check to Kconfig so that the check is
> done at configuration time, rather than build time, as builds with no
> configuration change will be quicker because the cc-option call will not
> need to happen in those instances.
>
> Suggested-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> ---
>
> v1 -> v2: https://lore.kernel.org/r/20220120214001.1879469-2-nathan@xxxxxxxxxx/
>
> * Move cc-option call to Kconfig (Nick).
> * Also apply to loongson2ef, even though this will not currently build
> with clang.
>
> arch/mips/Kconfig | 4 ++++
> arch/mips/loongson2ef/Platform | 3 ++-
> arch/mips/loongson64/Platform | 3 ++-
> 3 files changed, 8 insertions(+), 2 deletions(-)

applied to mips-next.

Thomas.

--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]