[PATCH] x86_64: Use %xmmN with vpxor to clear a vector register

[H.J. Lu]

On Thu, Jun 11, 2020 at 12:44 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> Since "vpxor %xmmN, %xmmN, %xmmN" clears the whole vector register, use
> %xmmN, instead of %ymmN, with vpxor to clear a vector register.
> ---
>  sysdeps/x86_64/multiarch/strcmp-avx2.S  | 4 ++--
>  sysdeps/x86_64/multiarch/strrchr-avx2.S | 2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> index 48d03a9f46..5f88a68262 100644
> --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S
> +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S
> @@ -91,8 +91,8 @@ ENTRY (STRCMP)
>  # endif
>         movl    %edi, %eax
>         xorl    %edx, %edx
> -       /* Make %ymm7 all zeros in this function.  */
> -       vpxor   %ymm7, %ymm7, %ymm7
> +       /* Make %xmm7 (%ymm7) all zeros in this function.  */
> +       vpxor   %xmm7, %xmm7, %xmm7
>         orl     %esi, %eax
>         andl    $(PAGE_SIZE - 1), %eax
>         cmpl    $(PAGE_SIZE - (VEC_SIZE * 4)), %eax
> diff --git a/sysdeps/x86_64/multiarch/strrchr-avx2.S b/sysdeps/x86_64/multiarch/strrchr-avx2.S
> index 23077b4c45..146bdd51d0 100644
> --- a/sysdeps/x86_64/multiarch/strrchr-avx2.S
> +++ b/sysdeps/x86_64/multiarch/strrchr-avx2.S
> @@ -44,7 +44,7 @@ ENTRY (STRRCHR)
>         movl    %edi, %ecx
>         /* Broadcast CHAR to YMM4.  */
>         VPBROADCAST %xmm4, %ymm4
> -       vpxor   %ymm0, %ymm0, %ymm0
> +       vpxor   %xmm0, %xmm0, %xmm0
>
>         /* Check if we may cross page boundary with one vector load.  */
>         andl    $(2 * VEC_SIZE - 1), %ecx
> --
> 2.26.2
>

I am checking it in.

-- 
H.J.