Re: [PATCH] x86-64: Fix SSE2 memcmp and SSSE3 memmove for x32

[Noah Goldstein <goldstein.w.n@gmail.com>]

On Fri, Apr 22, 2022 at 12:58 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> Clear the upper 32 bits in RDX (memory size) for x32 to fix
>
> FAIL: string/tst-size_t-memcmp
> FAIL: string/tst-size_t-memcmp-2
> FAIL: string/tst-size_t-memcpy
> FAIL: wcsmbs/tst-size_t-wmemcmp
>
> on x32 introduced by
>
> 8804157ad9 x86: Optimize memcmp SSE2 in memcmp.S
> 26b2478322 x86: Reduce code size of mem{move|pcpy|cpy}-ssse3
> ---
>  sysdeps/x86_64/memcmp.S                  | 4 ++++
>  sysdeps/x86_64/multiarch/memmove-ssse3.S | 4 ++++
>  2 files changed, 8 insertions(+)
>
> diff --git a/sysdeps/x86_64/memcmp.S b/sysdeps/x86_64/memcmp.S
> index b153694048..5718a7da86 100644
> --- a/sysdeps/x86_64/memcmp.S
> +++ b/sysdeps/x86_64/memcmp.S
> @@ -46,6 +46,10 @@
>
>         .text
>  ENTRY(MEMCMP)
> +# ifdef __ILP32__
> +       /* Clear the upper 32 bits.  */
> +       movl    %edx, %edx
> +# endif
>  #ifdef USE_AS_WMEMCMP
>         /* Use 0xffff to test for mismatches on pmovmskb bitmask. Store
>            in ecx for code size. This is preferable to using `incw` as
> diff --git a/sysdeps/x86_64/multiarch/memmove-ssse3.S b/sysdeps/x86_64/multiarch/memmove-ssse3.S
> index 215583e7bd..310ff62b86 100644
> --- a/sysdeps/x86_64/multiarch/memmove-ssse3.S
> +++ b/sysdeps/x86_64/multiarch/memmove-ssse3.S
> @@ -27,6 +27,10 @@ ENTRY(MEMMOVE_CHK)
>  END(MEMMOVE_CHK)
>
>  ENTRY_P2ALIGN(MEMMOVE, 6)
> +# ifdef __ILP32__
> +       /* Clear the upper 32 bits.  */
> +       movl    %edx, %edx
> +# endif
>         movq    %rdi, %rax
>  L(start):
>         cmpq    $16, %rdx
> --
> 2.35.1
>

LGTM.