[PATCH] x86-64: Define __memcmpeq in ld.so

[H.J. Lu]

On Mon, Feb 14, 2022 at 1:18 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Sun, Feb 13, 2022 at 8:46 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > Define __memcmpeq in ld.so so that compiler can generate __memcmpeq call
> > when compiling for ld.so.
> > ---
> >  sysdeps/x86_64/multiarch/memcmpeq-sse2.S | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/sysdeps/x86_64/multiarch/memcmpeq-sse2.S b/sysdeps/x86_64/multiarch/memcmpeq-sse2.S
> > index b80a29d4b0..de7f5a7525 100644
> > --- a/sysdeps/x86_64/multiarch/memcmpeq-sse2.S
> > +++ b/sysdeps/x86_64/multiarch/memcmpeq-sse2.S
> > @@ -16,8 +16,10 @@
> >     License along with the GNU C Library; if not, see
> >     <https://www.gnu.org/licenses/>.  */
> >
> > -#ifndef memcmp
> > +#if IS_IN (libc)
> >  # define memcmp        __memcmpeq_sse2
> > +#else
> > +# define memcmp        __memcmpeq
> >  #endif
> >  #define USE_AS_MEMCMPEQ        1
> >  #include "memcmp-sse2.S"
>
> How can I test this patch?

Please build this GCC branch:

https://gitlab.com/x86-gcc/gcc/-/commits/users/hjl/memcmpeq/master

and use it to build glibc with

CC="gcc -fextra-libc-function=memcmpeq"

It will call __memcmpeq when possible.

-- 
H.J.