Re: [PATCH] linux/compiler-clang.h: define HAVE_BUILTIN_BSWAP*

[Kees Cook]

On Thu, Feb 25, 2021 at 05:45:09PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> Separating compiler-clang.h from compiler-gcc.h inadventently dropped the
> definitions of the three HAVE_BUILTIN_BSWAP macros, which requires falling
> back to the open-coded version and hoping that the compiler detects it.
> 
> Since all versions of clang support the __builtin_bswap interfaces,
> add back the flags and have the headers pick these up automatically.
> 
> This results in a 4% improvement of compilation speed for arm defconfig.
> 
> Fixes: 815f0ddb346c ("include/linux/compiler*.h: make compiler-*.h mutually exclusive")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-- 
Kees Cook