[v3,2/3] x86: Remove memcmp-sse4.S

Message ID 20220415172801.1525674-2-goldstein.w.n@gmail.com
State Committed
Headers
Series [v3,1/3] x86: Optimize memcmp SSE2 in memcmp.S |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Noah Goldstein April 15, 2022, 5:28 p.m. UTC
  Code didn't actually use any sse4 instructions since `ptest` was
removed in:

commit 2f9062d7171850451e6044ef78d91ff8c017b9c0
Author: Noah Goldstein <goldstein.w.n@gmail.com>
Date:   Wed Nov 10 16:18:56 2021 -0600

    x86: Shrink memcmp-sse4.S code size

The new memcmp-sse2 implementation is also faster.

geometric_mean(N=20) of page cross cases SSE2 / SSE4: 0.905

Note there are two regressions prefering SSE2 for Size = 1 and Size =
65.

Size = 1:
size, align0, align1, ret, New Time/Old Time
   1,      1,      1,   0,               1.2
   1,      1,      1,   1,             1.197
   1,      1,      1,  -1,               1.2

This is intentional. Size == 1 is significantly less hot based on
profiles of GCC11 and Python3 than sizes [4, 8] (which is made
hotter).

Python3 Size = 1        -> 13.64%
Python3 Size = [4, 8]   -> 60.92%

GCC11   Size = 1        ->  1.29%
GCC11   Size = [4, 8]   -> 33.86%

size, align0, align1, ret, New Time/Old Time
   4,      4,      4,   0,             0.622
   4,      4,      4,   1,             0.797
   4,      4,      4,  -1,             0.805
   5,      5,      5,   0,             0.623
   5,      5,      5,   1,             0.777
   5,      5,      5,  -1,             0.802
   6,      6,      6,   0,             0.625
   6,      6,      6,   1,             0.813
   6,      6,      6,  -1,             0.788
   7,      7,      7,   0,             0.625
   7,      7,      7,   1,             0.799
   7,      7,      7,  -1,             0.795
   8,      8,      8,   0,             0.625
   8,      8,      8,   1,             0.848
   8,      8,      8,  -1,             0.914
   9,      9,      9,   0,             0.625

Size = 65:
size, align0, align1, ret, New Time/Old Time
  65,      0,      0,   0,             1.103
  65,      0,      0,   1,             1.216
  65,      0,      0,  -1,             1.227
  65,     65,      0,   0,             1.091
  65,      0,     65,   1,              1.19
  65,     65,     65,  -1,             1.215

This is because A) the checks in range [65, 96] are now unrolled 2x
and B) because smaller values <= 16 are now given a hotter path. By
contrast the SSE4 version has a branch for Size = 80. The unrolled
version has get better performance for returns which need both
comparisons.

size, align0, align1, ret, New Time/Old Time
 128,      4,      8,   0,             0.858
 128,      4,      8,   1,             0.879
 128,      4,      8,  -1,             0.888

As well, out of microbenchmark environments that are not full
predictable the branch will have a real-cost.
---
 sysdeps/x86_64/multiarch/Makefile          |   2 -
 sysdeps/x86_64/multiarch/ifunc-impl-list.c |   4 -
 sysdeps/x86_64/multiarch/ifunc-memcmp.h    |   4 -
 sysdeps/x86_64/multiarch/memcmp-sse4.S     | 803 ---------------------
 4 files changed, 813 deletions(-)
 delete mode 100644 sysdeps/x86_64/multiarch/memcmp-sse4.S
  

Comments

H.J. Lu April 15, 2022, 5:32 p.m. UTC | #1
On Fri, Apr 15, 2022 at 10:28 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> Code didn't actually use any sse4 instructions since `ptest` was
> removed in:
>
> commit 2f9062d7171850451e6044ef78d91ff8c017b9c0
> Author: Noah Goldstein <goldstein.w.n@gmail.com>
> Date:   Wed Nov 10 16:18:56 2021 -0600
>
>     x86: Shrink memcmp-sse4.S code size
>
> The new memcmp-sse2 implementation is also faster.
>
> geometric_mean(N=20) of page cross cases SSE2 / SSE4: 0.905
>
> Note there are two regressions prefering SSE2 for Size = 1 and Size =
                                                     preferring

LGTM with the commit log typo fix.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>

Thanks.

> 65.
>
> Size = 1:
> size, align0, align1, ret, New Time/Old Time
>    1,      1,      1,   0,               1.2
>    1,      1,      1,   1,             1.197
>    1,      1,      1,  -1,               1.2
>
> This is intentional. Size == 1 is significantly less hot based on
> profiles of GCC11 and Python3 than sizes [4, 8] (which is made
> hotter).
>
> Python3 Size = 1        -> 13.64%
> Python3 Size = [4, 8]   -> 60.92%
>
> GCC11   Size = 1        ->  1.29%
> GCC11   Size = [4, 8]   -> 33.86%
>
> size, align0, align1, ret, New Time/Old Time
>    4,      4,      4,   0,             0.622
>    4,      4,      4,   1,             0.797
>    4,      4,      4,  -1,             0.805
>    5,      5,      5,   0,             0.623
>    5,      5,      5,   1,             0.777
>    5,      5,      5,  -1,             0.802
>    6,      6,      6,   0,             0.625
>    6,      6,      6,   1,             0.813
>    6,      6,      6,  -1,             0.788
>    7,      7,      7,   0,             0.625
>    7,      7,      7,   1,             0.799
>    7,      7,      7,  -1,             0.795
>    8,      8,      8,   0,             0.625
>    8,      8,      8,   1,             0.848
>    8,      8,      8,  -1,             0.914
>    9,      9,      9,   0,             0.625
>
> Size = 65:
> size, align0, align1, ret, New Time/Old Time
>   65,      0,      0,   0,             1.103
>   65,      0,      0,   1,             1.216
>   65,      0,      0,  -1,             1.227
>   65,     65,      0,   0,             1.091
>   65,      0,     65,   1,              1.19
>   65,     65,     65,  -1,             1.215
>
> This is because A) the checks in range [65, 96] are now unrolled 2x
> and B) because smaller values <= 16 are now given a hotter path. By
> contrast the SSE4 version has a branch for Size = 80. The unrolled
> version has get better performance for returns which need both
> comparisons.
>
> size, align0, align1, ret, New Time/Old Time
>  128,      4,      8,   0,             0.858
>  128,      4,      8,   1,             0.879
>  128,      4,      8,  -1,             0.888
>
> As well, out of microbenchmark environments that are not full
> predictable the branch will have a real-cost.
> ---
>  sysdeps/x86_64/multiarch/Makefile          |   2 -
>  sysdeps/x86_64/multiarch/ifunc-impl-list.c |   4 -
>  sysdeps/x86_64/multiarch/ifunc-memcmp.h    |   4 -
>  sysdeps/x86_64/multiarch/memcmp-sse4.S     | 803 ---------------------
>  4 files changed, 813 deletions(-)
>  delete mode 100644 sysdeps/x86_64/multiarch/memcmp-sse4.S
>
> diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
> index b573966966..0400ea332b 100644
> --- a/sysdeps/x86_64/multiarch/Makefile
> +++ b/sysdeps/x86_64/multiarch/Makefile
> @@ -11,7 +11,6 @@ sysdep_routines += \
>    memcmp-avx2-movbe-rtm \
>    memcmp-evex-movbe \
>    memcmp-sse2 \
> -  memcmp-sse4 \
>    memcmpeq-avx2 \
>    memcmpeq-avx2-rtm \
>    memcmpeq-evex \
> @@ -164,7 +163,6 @@ sysdep_routines += \
>    wmemcmp-avx2-movbe-rtm \
>    wmemcmp-evex-movbe \
>    wmemcmp-sse2 \
> -  wmemcmp-sse4 \
>  # sysdep_routines
>  endif
>
> diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> index c6008a73ed..a8afcf81bb 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> @@ -96,8 +96,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>                                && CPU_FEATURE_USABLE (BMI2)
>                                && CPU_FEATURE_USABLE (MOVBE)),
>                               __memcmp_evex_movbe)
> -             IFUNC_IMPL_ADD (array, i, memcmp, CPU_FEATURE_USABLE (SSE4_1),
> -                             __memcmp_sse4_1)
>               IFUNC_IMPL_ADD (array, i, memcmp, 1, __memcmp_sse2))
>
>  #ifdef SHARED
> @@ -809,8 +807,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>                                && CPU_FEATURE_USABLE (BMI2)
>                                && CPU_FEATURE_USABLE (MOVBE)),
>                               __wmemcmp_evex_movbe)
> -             IFUNC_IMPL_ADD (array, i, wmemcmp, CPU_FEATURE_USABLE (SSE4_1),
> -                             __wmemcmp_sse4_1)
>               IFUNC_IMPL_ADD (array, i, wmemcmp, 1, __wmemcmp_sse2))
>
>    /* Support sysdeps/x86_64/multiarch/wmemset.c.  */
> diff --git a/sysdeps/x86_64/multiarch/ifunc-memcmp.h b/sysdeps/x86_64/multiarch/ifunc-memcmp.h
> index 44759a3ad5..c743970fe3 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-memcmp.h
> +++ b/sysdeps/x86_64/multiarch/ifunc-memcmp.h
> @@ -20,7 +20,6 @@
>  # include <init-arch.h>
>
>  extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
> -extern __typeof (REDIRECT_NAME) OPTIMIZE (sse4_1) attribute_hidden;
>  extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe) attribute_hidden;
>  extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe_rtm) attribute_hidden;
>  extern __typeof (REDIRECT_NAME) OPTIMIZE (evex_movbe) attribute_hidden;
> @@ -46,8 +45,5 @@ IFUNC_SELECTOR (void)
>         return OPTIMIZE (avx2_movbe);
>      }
>
> -  if (CPU_FEATURE_USABLE_P (cpu_features, SSE4_1))
> -    return OPTIMIZE (sse4_1);
> -
>    return OPTIMIZE (sse2);
>  }
> diff --git a/sysdeps/x86_64/multiarch/memcmp-sse4.S b/sysdeps/x86_64/multiarch/memcmp-sse4.S
> deleted file mode 100644
> index cd57c1e2c7..0000000000
> --- a/sysdeps/x86_64/multiarch/memcmp-sse4.S
> +++ /dev/null
> @@ -1,803 +0,0 @@
> -/* memcmp with SSE4.1, wmemcmp with SSE4.1
> -   Copyright (C) 2010-2022 Free Software Foundation, Inc.
> -   This file is part of the GNU C Library.
> -
> -   The GNU C Library is free software; you can redistribute it and/or
> -   modify it under the terms of the GNU Lesser General Public
> -   License as published by the Free Software Foundation; either
> -   version 2.1 of the License, or (at your option) any later version.
> -
> -   The GNU C Library is distributed in the hope that it will be useful,
> -   but WITHOUT ANY WARRANTY; without even the implied warranty of
> -   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> -   Lesser General Public License for more details.
> -
> -   You should have received a copy of the GNU Lesser General Public
> -   License along with the GNU C Library; if not, see
> -   <https://www.gnu.org/licenses/>.  */
> -
> -#if IS_IN (libc)
> -
> -# include <sysdep.h>
> -
> -# ifndef MEMCMP
> -#  define MEMCMP       __memcmp_sse4_1
> -# endif
> -
> -#ifdef USE_AS_WMEMCMP
> -# define CMPEQ pcmpeqd
> -# define CHAR_SIZE     4
> -#else
> -# define CMPEQ pcmpeqb
> -# define CHAR_SIZE     1
> -#endif
> -
> -
> -/* Warning!
> -           wmemcmp has to use SIGNED comparison for elements.
> -           memcmp has to use UNSIGNED comparison for elemnts.
> -*/
> -
> -       .section .text.sse4.1,"ax",@progbits
> -ENTRY (MEMCMP)
> -# ifdef USE_AS_WMEMCMP
> -       shl     $2, %RDX_LP
> -# elif defined __ILP32__
> -       /* Clear the upper 32 bits.  */
> -       mov     %edx, %edx
> -# endif
> -       cmp     $79, %RDX_LP
> -       ja      L(79bytesormore)
> -
> -       cmp     $CHAR_SIZE, %RDX_LP
> -       jbe     L(firstbyte)
> -
> -       /* N in (CHAR_SIZE, 79) bytes.  */
> -       cmpl    $32, %edx
> -       ja      L(more_32_bytes)
> -
> -       cmpl    $16, %edx
> -       jae     L(16_to_32_bytes)
> -
> -# ifndef USE_AS_WMEMCMP
> -       cmpl    $8, %edx
> -       jae     L(8_to_16_bytes)
> -
> -       cmpl    $4, %edx
> -       jb      L(2_to_3_bytes)
> -
> -       movl    (%rdi), %eax
> -       movl    (%rsi), %ecx
> -
> -       bswap   %eax
> -       bswap   %ecx
> -
> -       shlq    $32, %rax
> -       shlq    $32, %rcx
> -
> -       movl    -4(%rdi, %rdx), %edi
> -       movl    -4(%rsi, %rdx), %esi
> -
> -       bswap   %edi
> -       bswap   %esi
> -
> -       orq     %rdi, %rax
> -       orq     %rsi, %rcx
> -       subq    %rcx, %rax
> -       cmovne  %edx, %eax
> -       sbbl    %ecx, %ecx
> -       orl     %ecx, %eax
> -       ret
> -
> -       .p2align 4,, 8
> -L(2_to_3_bytes):
> -       movzwl  (%rdi), %eax
> -       movzwl  (%rsi), %ecx
> -       shll    $8, %eax
> -       shll    $8, %ecx
> -       bswap   %eax
> -       bswap   %ecx
> -       movzbl  -1(%rdi, %rdx), %edi
> -       movzbl  -1(%rsi, %rdx), %esi
> -       orl     %edi, %eax
> -       orl     %esi, %ecx
> -       subl    %ecx, %eax
> -       ret
> -
> -       .p2align 4,, 8
> -L(8_to_16_bytes):
> -       movq    (%rdi), %rax
> -       movq    (%rsi), %rcx
> -
> -       bswap   %rax
> -       bswap   %rcx
> -
> -       subq    %rcx, %rax
> -       jne     L(8_to_16_bytes_done)
> -
> -       movq    -8(%rdi, %rdx), %rax
> -       movq    -8(%rsi, %rdx), %rcx
> -
> -       bswap   %rax
> -       bswap   %rcx
> -
> -       subq    %rcx, %rax
> -
> -L(8_to_16_bytes_done):
> -       cmovne  %edx, %eax
> -       sbbl    %ecx, %ecx
> -       orl     %ecx, %eax
> -       ret
> -# else
> -       xorl    %eax, %eax
> -       movl    (%rdi), %ecx
> -       cmpl    (%rsi), %ecx
> -       jne     L(8_to_16_bytes_done)
> -       movl    4(%rdi), %ecx
> -       cmpl    4(%rsi), %ecx
> -       jne     L(8_to_16_bytes_done)
> -       movl    -4(%rdi, %rdx), %ecx
> -       cmpl    -4(%rsi, %rdx), %ecx
> -       jne     L(8_to_16_bytes_done)
> -       ret
> -# endif
> -
> -       .p2align 4,, 3
> -L(ret_zero):
> -       xorl    %eax, %eax
> -L(zero):
> -       ret
> -
> -       .p2align 4,, 8
> -L(firstbyte):
> -       jb      L(ret_zero)
> -# ifdef USE_AS_WMEMCMP
> -       xorl    %eax, %eax
> -       movl    (%rdi), %ecx
> -       cmpl    (%rsi), %ecx
> -       je      L(zero)
> -L(8_to_16_bytes_done):
> -       setg    %al
> -       leal    -1(%rax, %rax), %eax
> -# else
> -       movzbl  (%rdi), %eax
> -       movzbl  (%rsi), %ecx
> -       sub     %ecx, %eax
> -# endif
> -       ret
> -
> -       .p2align 4
> -L(vec_return_begin_48):
> -       addq    $16, %rdi
> -       addq    $16, %rsi
> -L(vec_return_begin_32):
> -       bsfl    %eax, %eax
> -# ifdef USE_AS_WMEMCMP
> -       movl    32(%rdi, %rax), %ecx
> -       xorl    %edx, %edx
> -       cmpl    32(%rsi, %rax), %ecx
> -       setg    %dl
> -       leal    -1(%rdx, %rdx), %eax
> -# else
> -       movzbl  32(%rsi, %rax), %ecx
> -       movzbl  32(%rdi, %rax), %eax
> -       subl    %ecx, %eax
> -# endif
> -       ret
> -
> -       .p2align 4
> -L(vec_return_begin_16):
> -       addq    $16, %rdi
> -       addq    $16, %rsi
> -L(vec_return_begin):
> -       bsfl    %eax, %eax
> -# ifdef USE_AS_WMEMCMP
> -       movl    (%rdi, %rax), %ecx
> -       xorl    %edx, %edx
> -       cmpl    (%rsi, %rax), %ecx
> -       setg    %dl
> -       leal    -1(%rdx, %rdx), %eax
> -# else
> -       movzbl  (%rsi, %rax), %ecx
> -       movzbl  (%rdi, %rax), %eax
> -       subl    %ecx, %eax
> -# endif
> -       ret
> -
> -       .p2align 4
> -L(vec_return_end_16):
> -       subl    $16, %edx
> -L(vec_return_end):
> -       bsfl    %eax, %eax
> -       addl    %edx, %eax
> -# ifdef USE_AS_WMEMCMP
> -       movl    -16(%rdi, %rax), %ecx
> -       xorl    %edx, %edx
> -       cmpl    -16(%rsi, %rax), %ecx
> -       setg    %dl
> -       leal    -1(%rdx, %rdx), %eax
> -# else
> -       movzbl  -16(%rsi, %rax), %ecx
> -       movzbl  -16(%rdi, %rax), %eax
> -       subl    %ecx, %eax
> -# endif
> -       ret
> -
> -       .p2align 4,, 8
> -L(more_32_bytes):
> -       movdqu  (%rdi), %xmm0
> -       movdqu  (%rsi), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -       movdqu  16(%rdi), %xmm0
> -       movdqu  16(%rsi), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_16)
> -
> -       cmpl    $64, %edx
> -       jbe     L(32_to_64_bytes)
> -       movdqu  32(%rdi), %xmm0
> -       movdqu  32(%rsi), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_32)
> -
> -       .p2align 4,, 6
> -L(32_to_64_bytes):
> -       movdqu  -32(%rdi, %rdx), %xmm0
> -       movdqu  -32(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end_16)
> -
> -       movdqu  -16(%rdi, %rdx), %xmm0
> -       movdqu  -16(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end)
> -       ret
> -
> -       .p2align 4
> -L(16_to_32_bytes):
> -       movdqu  (%rdi), %xmm0
> -       movdqu  (%rsi), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -       movdqu  -16(%rdi, %rdx), %xmm0
> -       movdqu  -16(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end)
> -       ret
> -
> -
> -       .p2align 4
> -L(79bytesormore):
> -       movdqu  (%rdi), %xmm0
> -       movdqu  (%rsi), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -
> -       mov     %rsi, %rcx
> -       and     $-16, %rsi
> -       add     $16, %rsi
> -       sub     %rsi, %rcx
> -
> -       sub     %rcx, %rdi
> -       add     %rcx, %rdx
> -       test    $0xf, %rdi
> -       jz      L(2aligned)
> -
> -       cmp     $128, %rdx
> -       ja      L(128bytesormore)
> -
> -       .p2align 4,, 6
> -L(less128bytes):
> -       movdqu  (%rdi), %xmm1
> -       CMPEQ   (%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -       movdqu  16(%rdi), %xmm1
> -       CMPEQ   16(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_16)
> -
> -       movdqu  32(%rdi), %xmm1
> -       CMPEQ   32(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_32)
> -
> -       movdqu  48(%rdi), %xmm1
> -       CMPEQ   48(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_48)
> -
> -       cmp     $96, %rdx
> -       jb      L(32_to_64_bytes)
> -
> -       addq    $64, %rdi
> -       addq    $64, %rsi
> -       subq    $64, %rdx
> -
> -       .p2align 4,, 6
> -L(last_64_bytes):
> -       movdqu  (%rdi), %xmm1
> -       CMPEQ   (%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -       movdqu  16(%rdi), %xmm1
> -       CMPEQ   16(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_16)
> -
> -       movdqu  -32(%rdi, %rdx), %xmm0
> -       movdqu  -32(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end_16)
> -
> -       movdqu  -16(%rdi, %rdx), %xmm0
> -       movdqu  -16(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end)
> -       ret
> -
> -       .p2align 4
> -L(128bytesormore):
> -       cmp     $256, %rdx
> -       ja      L(unaligned_loop)
> -L(less256bytes):
> -       movdqu  (%rdi), %xmm1
> -       CMPEQ   (%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -       movdqu  16(%rdi), %xmm1
> -       CMPEQ   16(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_16)
> -
> -       movdqu  32(%rdi), %xmm1
> -       CMPEQ   32(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_32)
> -
> -       movdqu  48(%rdi), %xmm1
> -       CMPEQ   48(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_48)
> -
> -       addq    $64, %rdi
> -       addq    $64, %rsi
> -
> -       movdqu  (%rdi), %xmm1
> -       CMPEQ   (%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -       movdqu  16(%rdi), %xmm1
> -       CMPEQ   16(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_16)
> -
> -       movdqu  32(%rdi), %xmm1
> -       CMPEQ   32(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_32)
> -
> -       movdqu  48(%rdi), %xmm1
> -       CMPEQ   48(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_48)
> -
> -       addq    $-128, %rdx
> -       subq    $-64, %rsi
> -       subq    $-64, %rdi
> -
> -       cmp     $64, %rdx
> -       ja      L(less128bytes)
> -
> -       cmp     $32, %rdx
> -       ja      L(last_64_bytes)
> -
> -       movdqu  -32(%rdi, %rdx), %xmm0
> -       movdqu  -32(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end_16)
> -
> -       movdqu  -16(%rdi, %rdx), %xmm0
> -       movdqu  -16(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end)
> -       ret
> -
> -       .p2align 4
> -L(unaligned_loop):
> -# ifdef DATA_CACHE_SIZE_HALF
> -       mov     $DATA_CACHE_SIZE_HALF, %R8_LP
> -# else
> -       mov     __x86_data_cache_size_half(%rip), %R8_LP
> -# endif
> -       movq    %r8, %r9
> -       addq    %r8, %r8
> -       addq    %r9, %r8
> -       cmpq    %r8, %rdx
> -       ja      L(L2_L3_cache_unaligned)
> -       sub     $64, %rdx
> -       .p2align 4
> -L(64bytesormore_loop):
> -       movdqu  (%rdi), %xmm0
> -       movdqu  16(%rdi), %xmm1
> -       movdqu  32(%rdi), %xmm2
> -       movdqu  48(%rdi), %xmm3
> -
> -       CMPEQ   (%rsi), %xmm0
> -       CMPEQ   16(%rsi), %xmm1
> -       CMPEQ   32(%rsi), %xmm2
> -       CMPEQ   48(%rsi), %xmm3
> -
> -       pand    %xmm0, %xmm1
> -       pand    %xmm2, %xmm3
> -       pand    %xmm1, %xmm3
> -
> -       pmovmskb %xmm3, %eax
> -       incw    %ax
> -       jnz     L(64bytesormore_loop_end)
> -
> -       add     $64, %rsi
> -       add     $64, %rdi
> -       sub     $64, %rdx
> -       ja      L(64bytesormore_loop)
> -
> -       .p2align 4,, 6
> -L(loop_tail):
> -       addq    %rdx, %rdi
> -       movdqu  (%rdi), %xmm0
> -       movdqu  16(%rdi), %xmm1
> -       movdqu  32(%rdi), %xmm2
> -       movdqu  48(%rdi), %xmm3
> -
> -       addq    %rdx, %rsi
> -       movdqu  (%rsi), %xmm4
> -       movdqu  16(%rsi), %xmm5
> -       movdqu  32(%rsi), %xmm6
> -       movdqu  48(%rsi), %xmm7
> -
> -       CMPEQ   %xmm4, %xmm0
> -       CMPEQ   %xmm5, %xmm1
> -       CMPEQ   %xmm6, %xmm2
> -       CMPEQ   %xmm7, %xmm3
> -
> -       pand    %xmm0, %xmm1
> -       pand    %xmm2, %xmm3
> -       pand    %xmm1, %xmm3
> -
> -       pmovmskb %xmm3, %eax
> -       incw    %ax
> -       jnz     L(64bytesormore_loop_end)
> -       ret
> -
> -L(L2_L3_cache_unaligned):
> -       subq    $64, %rdx
> -       .p2align 4
> -L(L2_L3_unaligned_128bytes_loop):
> -       prefetchnta 0x1c0(%rdi)
> -       prefetchnta 0x1c0(%rsi)
> -
> -       movdqu  (%rdi), %xmm0
> -       movdqu  16(%rdi), %xmm1
> -       movdqu  32(%rdi), %xmm2
> -       movdqu  48(%rdi), %xmm3
> -
> -       CMPEQ   (%rsi), %xmm0
> -       CMPEQ   16(%rsi), %xmm1
> -       CMPEQ   32(%rsi), %xmm2
> -       CMPEQ   48(%rsi), %xmm3
> -
> -       pand    %xmm0, %xmm1
> -       pand    %xmm2, %xmm3
> -       pand    %xmm1, %xmm3
> -
> -       pmovmskb %xmm3, %eax
> -       incw    %ax
> -       jnz     L(64bytesormore_loop_end)
> -
> -       add     $64, %rsi
> -       add     $64, %rdi
> -       sub     $64, %rdx
> -       ja      L(L2_L3_unaligned_128bytes_loop)
> -       jmp     L(loop_tail)
> -
> -
> -       /* This case is for machines which are sensitive for unaligned
> -        * instructions.  */
> -       .p2align 4
> -L(2aligned):
> -       cmp     $128, %rdx
> -       ja      L(128bytesormorein2aligned)
> -L(less128bytesin2aligned):
> -       movdqa  (%rdi), %xmm1
> -       CMPEQ   (%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -       movdqa  16(%rdi), %xmm1
> -       CMPEQ   16(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_16)
> -
> -       movdqa  32(%rdi), %xmm1
> -       CMPEQ   32(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_32)
> -
> -       movdqa  48(%rdi), %xmm1
> -       CMPEQ   48(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_48)
> -
> -       cmp     $96, %rdx
> -       jb      L(32_to_64_bytes)
> -
> -       addq    $64, %rdi
> -       addq    $64, %rsi
> -       subq    $64, %rdx
> -
> -       .p2align 4,, 6
> -L(aligned_last_64_bytes):
> -       movdqa  (%rdi), %xmm1
> -       CMPEQ   (%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -       movdqa  16(%rdi), %xmm1
> -       CMPEQ   16(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_16)
> -
> -       movdqu  -32(%rdi, %rdx), %xmm0
> -       movdqu  -32(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end_16)
> -
> -       movdqu  -16(%rdi, %rdx), %xmm0
> -       movdqu  -16(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end)
> -       ret
> -
> -       .p2align 4
> -L(128bytesormorein2aligned):
> -       cmp     $256, %rdx
> -       ja      L(aligned_loop)
> -L(less256bytesin2alinged):
> -       movdqa  (%rdi), %xmm1
> -       CMPEQ   (%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -       movdqa  16(%rdi), %xmm1
> -       CMPEQ   16(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_16)
> -
> -       movdqa  32(%rdi), %xmm1
> -       CMPEQ   32(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_32)
> -
> -       movdqa  48(%rdi), %xmm1
> -       CMPEQ   48(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_48)
> -
> -       addq    $64, %rdi
> -       addq    $64, %rsi
> -
> -       movdqa  (%rdi), %xmm1
> -       CMPEQ   (%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin)
> -
> -       movdqa  16(%rdi), %xmm1
> -       CMPEQ   16(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_16)
> -
> -       movdqa  32(%rdi), %xmm1
> -       CMPEQ   32(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_32)
> -
> -       movdqa  48(%rdi), %xmm1
> -       CMPEQ   48(%rsi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_begin_48)
> -
> -       addq    $-128, %rdx
> -       subq    $-64, %rsi
> -       subq    $-64, %rdi
> -
> -       cmp     $64, %rdx
> -       ja      L(less128bytesin2aligned)
> -
> -       cmp     $32, %rdx
> -       ja      L(aligned_last_64_bytes)
> -
> -       movdqu  -32(%rdi, %rdx), %xmm0
> -       movdqu  -32(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end_16)
> -
> -       movdqu  -16(%rdi, %rdx), %xmm0
> -       movdqu  -16(%rsi, %rdx), %xmm1
> -       CMPEQ   %xmm0, %xmm1
> -       pmovmskb %xmm1, %eax
> -       incw    %ax
> -       jnz     L(vec_return_end)
> -       ret
> -
> -       .p2align 4
> -L(aligned_loop):
> -# ifdef DATA_CACHE_SIZE_HALF
> -       mov     $DATA_CACHE_SIZE_HALF, %R8_LP
> -# else
> -       mov     __x86_data_cache_size_half(%rip), %R8_LP
> -# endif
> -       movq    %r8, %r9
> -       addq    %r8, %r8
> -       addq    %r9, %r8
> -       cmpq    %r8, %rdx
> -       ja      L(L2_L3_cache_aligned)
> -
> -       sub     $64, %rdx
> -       .p2align 4
> -L(64bytesormore_loopin2aligned):
> -       movdqa  (%rdi), %xmm0
> -       movdqa  16(%rdi), %xmm1
> -       movdqa  32(%rdi), %xmm2
> -       movdqa  48(%rdi), %xmm3
> -
> -       CMPEQ   (%rsi), %xmm0
> -       CMPEQ   16(%rsi), %xmm1
> -       CMPEQ   32(%rsi), %xmm2
> -       CMPEQ   48(%rsi), %xmm3
> -
> -       pand    %xmm0, %xmm1
> -       pand    %xmm2, %xmm3
> -       pand    %xmm1, %xmm3
> -
> -       pmovmskb %xmm3, %eax
> -       incw    %ax
> -       jnz     L(64bytesormore_loop_end)
> -       add     $64, %rsi
> -       add     $64, %rdi
> -       sub     $64, %rdx
> -       ja      L(64bytesormore_loopin2aligned)
> -       jmp     L(loop_tail)
> -
> -L(L2_L3_cache_aligned):
> -       subq    $64, %rdx
> -       .p2align 4
> -L(L2_L3_aligned_128bytes_loop):
> -       prefetchnta 0x1c0(%rdi)
> -       prefetchnta 0x1c0(%rsi)
> -       movdqa  (%rdi), %xmm0
> -       movdqa  16(%rdi), %xmm1
> -       movdqa  32(%rdi), %xmm2
> -       movdqa  48(%rdi), %xmm3
> -
> -       CMPEQ   (%rsi), %xmm0
> -       CMPEQ   16(%rsi), %xmm1
> -       CMPEQ   32(%rsi), %xmm2
> -       CMPEQ   48(%rsi), %xmm3
> -
> -       pand    %xmm0, %xmm1
> -       pand    %xmm2, %xmm3
> -       pand    %xmm1, %xmm3
> -
> -       pmovmskb %xmm3, %eax
> -       incw    %ax
> -       jnz     L(64bytesormore_loop_end)
> -
> -       addq    $64, %rsi
> -       addq    $64, %rdi
> -       subq    $64, %rdx
> -       ja      L(L2_L3_aligned_128bytes_loop)
> -       jmp     L(loop_tail)
> -
> -       .p2align 4
> -L(64bytesormore_loop_end):
> -       pmovmskb %xmm0, %ecx
> -       incw    %cx
> -       jnz     L(loop_end_ret)
> -
> -       pmovmskb %xmm1, %ecx
> -       notw    %cx
> -       sall    $16, %ecx
> -       jnz     L(loop_end_ret)
> -
> -       pmovmskb %xmm2, %ecx
> -       notw    %cx
> -       shlq    $32, %rcx
> -       jnz     L(loop_end_ret)
> -
> -       addq    $48, %rdi
> -       addq    $48, %rsi
> -       movq    %rax, %rcx
> -
> -       .p2align 4,, 6
> -L(loop_end_ret):
> -       bsfq    %rcx, %rcx
> -# ifdef USE_AS_WMEMCMP
> -       movl    (%rdi, %rcx), %eax
> -       xorl    %edx, %edx
> -       cmpl    (%rsi, %rcx), %eax
> -       setg    %dl
> -       leal    -1(%rdx, %rdx), %eax
> -# else
> -       movzbl  (%rdi, %rcx), %eax
> -       movzbl  (%rsi, %rcx), %ecx
> -       subl    %ecx, %eax
> -# endif
> -       ret
> -END (MEMCMP)
> -#endif
> --
> 2.25.1
>
  
Sunil Pandey May 12, 2022, 8:01 p.m. UTC | #2
On Fri, Apr 15, 2022 at 10:33 AM H.J. Lu via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> On Fri, Apr 15, 2022 at 10:28 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
> >
> > Code didn't actually use any sse4 instructions since `ptest` was
> > removed in:
> >
> > commit 2f9062d7171850451e6044ef78d91ff8c017b9c0
> > Author: Noah Goldstein <goldstein.w.n@gmail.com>
> > Date:   Wed Nov 10 16:18:56 2021 -0600
> >
> >     x86: Shrink memcmp-sse4.S code size
> >
> > The new memcmp-sse2 implementation is also faster.
> >
> > geometric_mean(N=20) of page cross cases SSE2 / SSE4: 0.905
> >
> > Note there are two regressions prefering SSE2 for Size = 1 and Size =
>                                                      preferring
>
> LGTM with the commit log typo fix.
>
> Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
>
> Thanks.
>
> > 65.
> >
> > Size = 1:
> > size, align0, align1, ret, New Time/Old Time
> >    1,      1,      1,   0,               1.2
> >    1,      1,      1,   1,             1.197
> >    1,      1,      1,  -1,               1.2
> >
> > This is intentional. Size == 1 is significantly less hot based on
> > profiles of GCC11 and Python3 than sizes [4, 8] (which is made
> > hotter).
> >
> > Python3 Size = 1        -> 13.64%
> > Python3 Size = [4, 8]   -> 60.92%
> >
> > GCC11   Size = 1        ->  1.29%
> > GCC11   Size = [4, 8]   -> 33.86%
> >
> > size, align0, align1, ret, New Time/Old Time
> >    4,      4,      4,   0,             0.622
> >    4,      4,      4,   1,             0.797
> >    4,      4,      4,  -1,             0.805
> >    5,      5,      5,   0,             0.623
> >    5,      5,      5,   1,             0.777
> >    5,      5,      5,  -1,             0.802
> >    6,      6,      6,   0,             0.625
> >    6,      6,      6,   1,             0.813
> >    6,      6,      6,  -1,             0.788
> >    7,      7,      7,   0,             0.625
> >    7,      7,      7,   1,             0.799
> >    7,      7,      7,  -1,             0.795
> >    8,      8,      8,   0,             0.625
> >    8,      8,      8,   1,             0.848
> >    8,      8,      8,  -1,             0.914
> >    9,      9,      9,   0,             0.625
> >
> > Size = 65:
> > size, align0, align1, ret, New Time/Old Time
> >   65,      0,      0,   0,             1.103
> >   65,      0,      0,   1,             1.216
> >   65,      0,      0,  -1,             1.227
> >   65,     65,      0,   0,             1.091
> >   65,      0,     65,   1,              1.19
> >   65,     65,     65,  -1,             1.215
> >
> > This is because A) the checks in range [65, 96] are now unrolled 2x
> > and B) because smaller values <= 16 are now given a hotter path. By
> > contrast the SSE4 version has a branch for Size = 80. The unrolled
> > version has get better performance for returns which need both
> > comparisons.
> >
> > size, align0, align1, ret, New Time/Old Time
> >  128,      4,      8,   0,             0.858
> >  128,      4,      8,   1,             0.879
> >  128,      4,      8,  -1,             0.888
> >
> > As well, out of microbenchmark environments that are not full
> > predictable the branch will have a real-cost.
> > ---
> >  sysdeps/x86_64/multiarch/Makefile          |   2 -
> >  sysdeps/x86_64/multiarch/ifunc-impl-list.c |   4 -
> >  sysdeps/x86_64/multiarch/ifunc-memcmp.h    |   4 -
> >  sysdeps/x86_64/multiarch/memcmp-sse4.S     | 803 ---------------------
> >  4 files changed, 813 deletions(-)
> >  delete mode 100644 sysdeps/x86_64/multiarch/memcmp-sse4.S
> >
> > diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
> > index b573966966..0400ea332b 100644
> > --- a/sysdeps/x86_64/multiarch/Makefile
> > +++ b/sysdeps/x86_64/multiarch/Makefile
> > @@ -11,7 +11,6 @@ sysdep_routines += \
> >    memcmp-avx2-movbe-rtm \
> >    memcmp-evex-movbe \
> >    memcmp-sse2 \
> > -  memcmp-sse4 \
> >    memcmpeq-avx2 \
> >    memcmpeq-avx2-rtm \
> >    memcmpeq-evex \
> > @@ -164,7 +163,6 @@ sysdep_routines += \
> >    wmemcmp-avx2-movbe-rtm \
> >    wmemcmp-evex-movbe \
> >    wmemcmp-sse2 \
> > -  wmemcmp-sse4 \
> >  # sysdep_routines
> >  endif
> >
> > diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > index c6008a73ed..a8afcf81bb 100644
> > --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > @@ -96,8 +96,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> >                                && CPU_FEATURE_USABLE (BMI2)
> >                                && CPU_FEATURE_USABLE (MOVBE)),
> >                               __memcmp_evex_movbe)
> > -             IFUNC_IMPL_ADD (array, i, memcmp, CPU_FEATURE_USABLE (SSE4_1),
> > -                             __memcmp_sse4_1)
> >               IFUNC_IMPL_ADD (array, i, memcmp, 1, __memcmp_sse2))
> >
> >  #ifdef SHARED
> > @@ -809,8 +807,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> >                                && CPU_FEATURE_USABLE (BMI2)
> >                                && CPU_FEATURE_USABLE (MOVBE)),
> >                               __wmemcmp_evex_movbe)
> > -             IFUNC_IMPL_ADD (array, i, wmemcmp, CPU_FEATURE_USABLE (SSE4_1),
> > -                             __wmemcmp_sse4_1)
> >               IFUNC_IMPL_ADD (array, i, wmemcmp, 1, __wmemcmp_sse2))
> >
> >    /* Support sysdeps/x86_64/multiarch/wmemset.c.  */
> > diff --git a/sysdeps/x86_64/multiarch/ifunc-memcmp.h b/sysdeps/x86_64/multiarch/ifunc-memcmp.h
> > index 44759a3ad5..c743970fe3 100644
> > --- a/sysdeps/x86_64/multiarch/ifunc-memcmp.h
> > +++ b/sysdeps/x86_64/multiarch/ifunc-memcmp.h
> > @@ -20,7 +20,6 @@
> >  # include <init-arch.h>
> >
> >  extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
> > -extern __typeof (REDIRECT_NAME) OPTIMIZE (sse4_1) attribute_hidden;
> >  extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe) attribute_hidden;
> >  extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe_rtm) attribute_hidden;
> >  extern __typeof (REDIRECT_NAME) OPTIMIZE (evex_movbe) attribute_hidden;
> > @@ -46,8 +45,5 @@ IFUNC_SELECTOR (void)
> >         return OPTIMIZE (avx2_movbe);
> >      }
> >
> > -  if (CPU_FEATURE_USABLE_P (cpu_features, SSE4_1))
> > -    return OPTIMIZE (sse4_1);
> > -
> >    return OPTIMIZE (sse2);
> >  }
> > diff --git a/sysdeps/x86_64/multiarch/memcmp-sse4.S b/sysdeps/x86_64/multiarch/memcmp-sse4.S
> > deleted file mode 100644
> > index cd57c1e2c7..0000000000
> > --- a/sysdeps/x86_64/multiarch/memcmp-sse4.S
> > +++ /dev/null
> > @@ -1,803 +0,0 @@
> > -/* memcmp with SSE4.1, wmemcmp with SSE4.1
> > -   Copyright (C) 2010-2022 Free Software Foundation, Inc.
> > -   This file is part of the GNU C Library.
> > -
> > -   The GNU C Library is free software; you can redistribute it and/or
> > -   modify it under the terms of the GNU Lesser General Public
> > -   License as published by the Free Software Foundation; either
> > -   version 2.1 of the License, or (at your option) any later version.
> > -
> > -   The GNU C Library is distributed in the hope that it will be useful,
> > -   but WITHOUT ANY WARRANTY; without even the implied warranty of
> > -   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > -   Lesser General Public License for more details.
> > -
> > -   You should have received a copy of the GNU Lesser General Public
> > -   License along with the GNU C Library; if not, see
> > -   <https://www.gnu.org/licenses/>.  */
> > -
> > -#if IS_IN (libc)
> > -
> > -# include <sysdep.h>
> > -
> > -# ifndef MEMCMP
> > -#  define MEMCMP       __memcmp_sse4_1
> > -# endif
> > -
> > -#ifdef USE_AS_WMEMCMP
> > -# define CMPEQ pcmpeqd
> > -# define CHAR_SIZE     4
> > -#else
> > -# define CMPEQ pcmpeqb
> > -# define CHAR_SIZE     1
> > -#endif
> > -
> > -
> > -/* Warning!
> > -           wmemcmp has to use SIGNED comparison for elements.
> > -           memcmp has to use UNSIGNED comparison for elemnts.
> > -*/
> > -
> > -       .section .text.sse4.1,"ax",@progbits
> > -ENTRY (MEMCMP)
> > -# ifdef USE_AS_WMEMCMP
> > -       shl     $2, %RDX_LP
> > -# elif defined __ILP32__
> > -       /* Clear the upper 32 bits.  */
> > -       mov     %edx, %edx
> > -# endif
> > -       cmp     $79, %RDX_LP
> > -       ja      L(79bytesormore)
> > -
> > -       cmp     $CHAR_SIZE, %RDX_LP
> > -       jbe     L(firstbyte)
> > -
> > -       /* N in (CHAR_SIZE, 79) bytes.  */
> > -       cmpl    $32, %edx
> > -       ja      L(more_32_bytes)
> > -
> > -       cmpl    $16, %edx
> > -       jae     L(16_to_32_bytes)
> > -
> > -# ifndef USE_AS_WMEMCMP
> > -       cmpl    $8, %edx
> > -       jae     L(8_to_16_bytes)
> > -
> > -       cmpl    $4, %edx
> > -       jb      L(2_to_3_bytes)
> > -
> > -       movl    (%rdi), %eax
> > -       movl    (%rsi), %ecx
> > -
> > -       bswap   %eax
> > -       bswap   %ecx
> > -
> > -       shlq    $32, %rax
> > -       shlq    $32, %rcx
> > -
> > -       movl    -4(%rdi, %rdx), %edi
> > -       movl    -4(%rsi, %rdx), %esi
> > -
> > -       bswap   %edi
> > -       bswap   %esi
> > -
> > -       orq     %rdi, %rax
> > -       orq     %rsi, %rcx
> > -       subq    %rcx, %rax
> > -       cmovne  %edx, %eax
> > -       sbbl    %ecx, %ecx
> > -       orl     %ecx, %eax
> > -       ret
> > -
> > -       .p2align 4,, 8
> > -L(2_to_3_bytes):
> > -       movzwl  (%rdi), %eax
> > -       movzwl  (%rsi), %ecx
> > -       shll    $8, %eax
> > -       shll    $8, %ecx
> > -       bswap   %eax
> > -       bswap   %ecx
> > -       movzbl  -1(%rdi, %rdx), %edi
> > -       movzbl  -1(%rsi, %rdx), %esi
> > -       orl     %edi, %eax
> > -       orl     %esi, %ecx
> > -       subl    %ecx, %eax
> > -       ret
> > -
> > -       .p2align 4,, 8
> > -L(8_to_16_bytes):
> > -       movq    (%rdi), %rax
> > -       movq    (%rsi), %rcx
> > -
> > -       bswap   %rax
> > -       bswap   %rcx
> > -
> > -       subq    %rcx, %rax
> > -       jne     L(8_to_16_bytes_done)
> > -
> > -       movq    -8(%rdi, %rdx), %rax
> > -       movq    -8(%rsi, %rdx), %rcx
> > -
> > -       bswap   %rax
> > -       bswap   %rcx
> > -
> > -       subq    %rcx, %rax
> > -
> > -L(8_to_16_bytes_done):
> > -       cmovne  %edx, %eax
> > -       sbbl    %ecx, %ecx
> > -       orl     %ecx, %eax
> > -       ret
> > -# else
> > -       xorl    %eax, %eax
> > -       movl    (%rdi), %ecx
> > -       cmpl    (%rsi), %ecx
> > -       jne     L(8_to_16_bytes_done)
> > -       movl    4(%rdi), %ecx
> > -       cmpl    4(%rsi), %ecx
> > -       jne     L(8_to_16_bytes_done)
> > -       movl    -4(%rdi, %rdx), %ecx
> > -       cmpl    -4(%rsi, %rdx), %ecx
> > -       jne     L(8_to_16_bytes_done)
> > -       ret
> > -# endif
> > -
> > -       .p2align 4,, 3
> > -L(ret_zero):
> > -       xorl    %eax, %eax
> > -L(zero):
> > -       ret
> > -
> > -       .p2align 4,, 8
> > -L(firstbyte):
> > -       jb      L(ret_zero)
> > -# ifdef USE_AS_WMEMCMP
> > -       xorl    %eax, %eax
> > -       movl    (%rdi), %ecx
> > -       cmpl    (%rsi), %ecx
> > -       je      L(zero)
> > -L(8_to_16_bytes_done):
> > -       setg    %al
> > -       leal    -1(%rax, %rax), %eax
> > -# else
> > -       movzbl  (%rdi), %eax
> > -       movzbl  (%rsi), %ecx
> > -       sub     %ecx, %eax
> > -# endif
> > -       ret
> > -
> > -       .p2align 4
> > -L(vec_return_begin_48):
> > -       addq    $16, %rdi
> > -       addq    $16, %rsi
> > -L(vec_return_begin_32):
> > -       bsfl    %eax, %eax
> > -# ifdef USE_AS_WMEMCMP
> > -       movl    32(%rdi, %rax), %ecx
> > -       xorl    %edx, %edx
> > -       cmpl    32(%rsi, %rax), %ecx
> > -       setg    %dl
> > -       leal    -1(%rdx, %rdx), %eax
> > -# else
> > -       movzbl  32(%rsi, %rax), %ecx
> > -       movzbl  32(%rdi, %rax), %eax
> > -       subl    %ecx, %eax
> > -# endif
> > -       ret
> > -
> > -       .p2align 4
> > -L(vec_return_begin_16):
> > -       addq    $16, %rdi
> > -       addq    $16, %rsi
> > -L(vec_return_begin):
> > -       bsfl    %eax, %eax
> > -# ifdef USE_AS_WMEMCMP
> > -       movl    (%rdi, %rax), %ecx
> > -       xorl    %edx, %edx
> > -       cmpl    (%rsi, %rax), %ecx
> > -       setg    %dl
> > -       leal    -1(%rdx, %rdx), %eax
> > -# else
> > -       movzbl  (%rsi, %rax), %ecx
> > -       movzbl  (%rdi, %rax), %eax
> > -       subl    %ecx, %eax
> > -# endif
> > -       ret
> > -
> > -       .p2align 4
> > -L(vec_return_end_16):
> > -       subl    $16, %edx
> > -L(vec_return_end):
> > -       bsfl    %eax, %eax
> > -       addl    %edx, %eax
> > -# ifdef USE_AS_WMEMCMP
> > -       movl    -16(%rdi, %rax), %ecx
> > -       xorl    %edx, %edx
> > -       cmpl    -16(%rsi, %rax), %ecx
> > -       setg    %dl
> > -       leal    -1(%rdx, %rdx), %eax
> > -# else
> > -       movzbl  -16(%rsi, %rax), %ecx
> > -       movzbl  -16(%rdi, %rax), %eax
> > -       subl    %ecx, %eax
> > -# endif
> > -       ret
> > -
> > -       .p2align 4,, 8
> > -L(more_32_bytes):
> > -       movdqu  (%rdi), %xmm0
> > -       movdqu  (%rsi), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -       movdqu  16(%rdi), %xmm0
> > -       movdqu  16(%rsi), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_16)
> > -
> > -       cmpl    $64, %edx
> > -       jbe     L(32_to_64_bytes)
> > -       movdqu  32(%rdi), %xmm0
> > -       movdqu  32(%rsi), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_32)
> > -
> > -       .p2align 4,, 6
> > -L(32_to_64_bytes):
> > -       movdqu  -32(%rdi, %rdx), %xmm0
> > -       movdqu  -32(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end_16)
> > -
> > -       movdqu  -16(%rdi, %rdx), %xmm0
> > -       movdqu  -16(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end)
> > -       ret
> > -
> > -       .p2align 4
> > -L(16_to_32_bytes):
> > -       movdqu  (%rdi), %xmm0
> > -       movdqu  (%rsi), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -       movdqu  -16(%rdi, %rdx), %xmm0
> > -       movdqu  -16(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end)
> > -       ret
> > -
> > -
> > -       .p2align 4
> > -L(79bytesormore):
> > -       movdqu  (%rdi), %xmm0
> > -       movdqu  (%rsi), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -
> > -       mov     %rsi, %rcx
> > -       and     $-16, %rsi
> > -       add     $16, %rsi
> > -       sub     %rsi, %rcx
> > -
> > -       sub     %rcx, %rdi
> > -       add     %rcx, %rdx
> > -       test    $0xf, %rdi
> > -       jz      L(2aligned)
> > -
> > -       cmp     $128, %rdx
> > -       ja      L(128bytesormore)
> > -
> > -       .p2align 4,, 6
> > -L(less128bytes):
> > -       movdqu  (%rdi), %xmm1
> > -       CMPEQ   (%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -       movdqu  16(%rdi), %xmm1
> > -       CMPEQ   16(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_16)
> > -
> > -       movdqu  32(%rdi), %xmm1
> > -       CMPEQ   32(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_32)
> > -
> > -       movdqu  48(%rdi), %xmm1
> > -       CMPEQ   48(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_48)
> > -
> > -       cmp     $96, %rdx
> > -       jb      L(32_to_64_bytes)
> > -
> > -       addq    $64, %rdi
> > -       addq    $64, %rsi
> > -       subq    $64, %rdx
> > -
> > -       .p2align 4,, 6
> > -L(last_64_bytes):
> > -       movdqu  (%rdi), %xmm1
> > -       CMPEQ   (%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -       movdqu  16(%rdi), %xmm1
> > -       CMPEQ   16(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_16)
> > -
> > -       movdqu  -32(%rdi, %rdx), %xmm0
> > -       movdqu  -32(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end_16)
> > -
> > -       movdqu  -16(%rdi, %rdx), %xmm0
> > -       movdqu  -16(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end)
> > -       ret
> > -
> > -       .p2align 4
> > -L(128bytesormore):
> > -       cmp     $256, %rdx
> > -       ja      L(unaligned_loop)
> > -L(less256bytes):
> > -       movdqu  (%rdi), %xmm1
> > -       CMPEQ   (%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -       movdqu  16(%rdi), %xmm1
> > -       CMPEQ   16(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_16)
> > -
> > -       movdqu  32(%rdi), %xmm1
> > -       CMPEQ   32(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_32)
> > -
> > -       movdqu  48(%rdi), %xmm1
> > -       CMPEQ   48(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_48)
> > -
> > -       addq    $64, %rdi
> > -       addq    $64, %rsi
> > -
> > -       movdqu  (%rdi), %xmm1
> > -       CMPEQ   (%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -       movdqu  16(%rdi), %xmm1
> > -       CMPEQ   16(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_16)
> > -
> > -       movdqu  32(%rdi), %xmm1
> > -       CMPEQ   32(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_32)
> > -
> > -       movdqu  48(%rdi), %xmm1
> > -       CMPEQ   48(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_48)
> > -
> > -       addq    $-128, %rdx
> > -       subq    $-64, %rsi
> > -       subq    $-64, %rdi
> > -
> > -       cmp     $64, %rdx
> > -       ja      L(less128bytes)
> > -
> > -       cmp     $32, %rdx
> > -       ja      L(last_64_bytes)
> > -
> > -       movdqu  -32(%rdi, %rdx), %xmm0
> > -       movdqu  -32(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end_16)
> > -
> > -       movdqu  -16(%rdi, %rdx), %xmm0
> > -       movdqu  -16(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end)
> > -       ret
> > -
> > -       .p2align 4
> > -L(unaligned_loop):
> > -# ifdef DATA_CACHE_SIZE_HALF
> > -       mov     $DATA_CACHE_SIZE_HALF, %R8_LP
> > -# else
> > -       mov     __x86_data_cache_size_half(%rip), %R8_LP
> > -# endif
> > -       movq    %r8, %r9
> > -       addq    %r8, %r8
> > -       addq    %r9, %r8
> > -       cmpq    %r8, %rdx
> > -       ja      L(L2_L3_cache_unaligned)
> > -       sub     $64, %rdx
> > -       .p2align 4
> > -L(64bytesormore_loop):
> > -       movdqu  (%rdi), %xmm0
> > -       movdqu  16(%rdi), %xmm1
> > -       movdqu  32(%rdi), %xmm2
> > -       movdqu  48(%rdi), %xmm3
> > -
> > -       CMPEQ   (%rsi), %xmm0
> > -       CMPEQ   16(%rsi), %xmm1
> > -       CMPEQ   32(%rsi), %xmm2
> > -       CMPEQ   48(%rsi), %xmm3
> > -
> > -       pand    %xmm0, %xmm1
> > -       pand    %xmm2, %xmm3
> > -       pand    %xmm1, %xmm3
> > -
> > -       pmovmskb %xmm3, %eax
> > -       incw    %ax
> > -       jnz     L(64bytesormore_loop_end)
> > -
> > -       add     $64, %rsi
> > -       add     $64, %rdi
> > -       sub     $64, %rdx
> > -       ja      L(64bytesormore_loop)
> > -
> > -       .p2align 4,, 6
> > -L(loop_tail):
> > -       addq    %rdx, %rdi
> > -       movdqu  (%rdi), %xmm0
> > -       movdqu  16(%rdi), %xmm1
> > -       movdqu  32(%rdi), %xmm2
> > -       movdqu  48(%rdi), %xmm3
> > -
> > -       addq    %rdx, %rsi
> > -       movdqu  (%rsi), %xmm4
> > -       movdqu  16(%rsi), %xmm5
> > -       movdqu  32(%rsi), %xmm6
> > -       movdqu  48(%rsi), %xmm7
> > -
> > -       CMPEQ   %xmm4, %xmm0
> > -       CMPEQ   %xmm5, %xmm1
> > -       CMPEQ   %xmm6, %xmm2
> > -       CMPEQ   %xmm7, %xmm3
> > -
> > -       pand    %xmm0, %xmm1
> > -       pand    %xmm2, %xmm3
> > -       pand    %xmm1, %xmm3
> > -
> > -       pmovmskb %xmm3, %eax
> > -       incw    %ax
> > -       jnz     L(64bytesormore_loop_end)
> > -       ret
> > -
> > -L(L2_L3_cache_unaligned):
> > -       subq    $64, %rdx
> > -       .p2align 4
> > -L(L2_L3_unaligned_128bytes_loop):
> > -       prefetchnta 0x1c0(%rdi)
> > -       prefetchnta 0x1c0(%rsi)
> > -
> > -       movdqu  (%rdi), %xmm0
> > -       movdqu  16(%rdi), %xmm1
> > -       movdqu  32(%rdi), %xmm2
> > -       movdqu  48(%rdi), %xmm3
> > -
> > -       CMPEQ   (%rsi), %xmm0
> > -       CMPEQ   16(%rsi), %xmm1
> > -       CMPEQ   32(%rsi), %xmm2
> > -       CMPEQ   48(%rsi), %xmm3
> > -
> > -       pand    %xmm0, %xmm1
> > -       pand    %xmm2, %xmm3
> > -       pand    %xmm1, %xmm3
> > -
> > -       pmovmskb %xmm3, %eax
> > -       incw    %ax
> > -       jnz     L(64bytesormore_loop_end)
> > -
> > -       add     $64, %rsi
> > -       add     $64, %rdi
> > -       sub     $64, %rdx
> > -       ja      L(L2_L3_unaligned_128bytes_loop)
> > -       jmp     L(loop_tail)
> > -
> > -
> > -       /* This case is for machines which are sensitive for unaligned
> > -        * instructions.  */
> > -       .p2align 4
> > -L(2aligned):
> > -       cmp     $128, %rdx
> > -       ja      L(128bytesormorein2aligned)
> > -L(less128bytesin2aligned):
> > -       movdqa  (%rdi), %xmm1
> > -       CMPEQ   (%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -       movdqa  16(%rdi), %xmm1
> > -       CMPEQ   16(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_16)
> > -
> > -       movdqa  32(%rdi), %xmm1
> > -       CMPEQ   32(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_32)
> > -
> > -       movdqa  48(%rdi), %xmm1
> > -       CMPEQ   48(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_48)
> > -
> > -       cmp     $96, %rdx
> > -       jb      L(32_to_64_bytes)
> > -
> > -       addq    $64, %rdi
> > -       addq    $64, %rsi
> > -       subq    $64, %rdx
> > -
> > -       .p2align 4,, 6
> > -L(aligned_last_64_bytes):
> > -       movdqa  (%rdi), %xmm1
> > -       CMPEQ   (%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -       movdqa  16(%rdi), %xmm1
> > -       CMPEQ   16(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_16)
> > -
> > -       movdqu  -32(%rdi, %rdx), %xmm0
> > -       movdqu  -32(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end_16)
> > -
> > -       movdqu  -16(%rdi, %rdx), %xmm0
> > -       movdqu  -16(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end)
> > -       ret
> > -
> > -       .p2align 4
> > -L(128bytesormorein2aligned):
> > -       cmp     $256, %rdx
> > -       ja      L(aligned_loop)
> > -L(less256bytesin2alinged):
> > -       movdqa  (%rdi), %xmm1
> > -       CMPEQ   (%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -       movdqa  16(%rdi), %xmm1
> > -       CMPEQ   16(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_16)
> > -
> > -       movdqa  32(%rdi), %xmm1
> > -       CMPEQ   32(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_32)
> > -
> > -       movdqa  48(%rdi), %xmm1
> > -       CMPEQ   48(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_48)
> > -
> > -       addq    $64, %rdi
> > -       addq    $64, %rsi
> > -
> > -       movdqa  (%rdi), %xmm1
> > -       CMPEQ   (%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin)
> > -
> > -       movdqa  16(%rdi), %xmm1
> > -       CMPEQ   16(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_16)
> > -
> > -       movdqa  32(%rdi), %xmm1
> > -       CMPEQ   32(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_32)
> > -
> > -       movdqa  48(%rdi), %xmm1
> > -       CMPEQ   48(%rsi), %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_begin_48)
> > -
> > -       addq    $-128, %rdx
> > -       subq    $-64, %rsi
> > -       subq    $-64, %rdi
> > -
> > -       cmp     $64, %rdx
> > -       ja      L(less128bytesin2aligned)
> > -
> > -       cmp     $32, %rdx
> > -       ja      L(aligned_last_64_bytes)
> > -
> > -       movdqu  -32(%rdi, %rdx), %xmm0
> > -       movdqu  -32(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end_16)
> > -
> > -       movdqu  -16(%rdi, %rdx), %xmm0
> > -       movdqu  -16(%rsi, %rdx), %xmm1
> > -       CMPEQ   %xmm0, %xmm1
> > -       pmovmskb %xmm1, %eax
> > -       incw    %ax
> > -       jnz     L(vec_return_end)
> > -       ret
> > -
> > -       .p2align 4
> > -L(aligned_loop):
> > -# ifdef DATA_CACHE_SIZE_HALF
> > -       mov     $DATA_CACHE_SIZE_HALF, %R8_LP
> > -# else
> > -       mov     __x86_data_cache_size_half(%rip), %R8_LP
> > -# endif
> > -       movq    %r8, %r9
> > -       addq    %r8, %r8
> > -       addq    %r9, %r8
> > -       cmpq    %r8, %rdx
> > -       ja      L(L2_L3_cache_aligned)
> > -
> > -       sub     $64, %rdx
> > -       .p2align 4
> > -L(64bytesormore_loopin2aligned):
> > -       movdqa  (%rdi), %xmm0
> > -       movdqa  16(%rdi), %xmm1
> > -       movdqa  32(%rdi), %xmm2
> > -       movdqa  48(%rdi), %xmm3
> > -
> > -       CMPEQ   (%rsi), %xmm0
> > -       CMPEQ   16(%rsi), %xmm1
> > -       CMPEQ   32(%rsi), %xmm2
> > -       CMPEQ   48(%rsi), %xmm3
> > -
> > -       pand    %xmm0, %xmm1
> > -       pand    %xmm2, %xmm3
> > -       pand    %xmm1, %xmm3
> > -
> > -       pmovmskb %xmm3, %eax
> > -       incw    %ax
> > -       jnz     L(64bytesormore_loop_end)
> > -       add     $64, %rsi
> > -       add     $64, %rdi
> > -       sub     $64, %rdx
> > -       ja      L(64bytesormore_loopin2aligned)
> > -       jmp     L(loop_tail)
> > -
> > -L(L2_L3_cache_aligned):
> > -       subq    $64, %rdx
> > -       .p2align 4
> > -L(L2_L3_aligned_128bytes_loop):
> > -       prefetchnta 0x1c0(%rdi)
> > -       prefetchnta 0x1c0(%rsi)
> > -       movdqa  (%rdi), %xmm0
> > -       movdqa  16(%rdi), %xmm1
> > -       movdqa  32(%rdi), %xmm2
> > -       movdqa  48(%rdi), %xmm3
> > -
> > -       CMPEQ   (%rsi), %xmm0
> > -       CMPEQ   16(%rsi), %xmm1
> > -       CMPEQ   32(%rsi), %xmm2
> > -       CMPEQ   48(%rsi), %xmm3
> > -
> > -       pand    %xmm0, %xmm1
> > -       pand    %xmm2, %xmm3
> > -       pand    %xmm1, %xmm3
> > -
> > -       pmovmskb %xmm3, %eax
> > -       incw    %ax
> > -       jnz     L(64bytesormore_loop_end)
> > -
> > -       addq    $64, %rsi
> > -       addq    $64, %rdi
> > -       subq    $64, %rdx
> > -       ja      L(L2_L3_aligned_128bytes_loop)
> > -       jmp     L(loop_tail)
> > -
> > -       .p2align 4
> > -L(64bytesormore_loop_end):
> > -       pmovmskb %xmm0, %ecx
> > -       incw    %cx
> > -       jnz     L(loop_end_ret)
> > -
> > -       pmovmskb %xmm1, %ecx
> > -       notw    %cx
> > -       sall    $16, %ecx
> > -       jnz     L(loop_end_ret)
> > -
> > -       pmovmskb %xmm2, %ecx
> > -       notw    %cx
> > -       shlq    $32, %rcx
> > -       jnz     L(loop_end_ret)
> > -
> > -       addq    $48, %rdi
> > -       addq    $48, %rsi
> > -       movq    %rax, %rcx
> > -
> > -       .p2align 4,, 6
> > -L(loop_end_ret):
> > -       bsfq    %rcx, %rcx
> > -# ifdef USE_AS_WMEMCMP
> > -       movl    (%rdi, %rcx), %eax
> > -       xorl    %edx, %edx
> > -       cmpl    (%rsi, %rcx), %eax
> > -       setg    %dl
> > -       leal    -1(%rdx, %rdx), %eax
> > -# else
> > -       movzbl  (%rdi, %rcx), %eax
> > -       movzbl  (%rsi, %rcx), %ecx
> > -       subl    %ecx, %eax
> > -# endif
> > -       ret
> > -END (MEMCMP)
> > -#endif
> > --
> > 2.25.1
> >
>
>
> --
> H.J.

I would like to backport this patch to release branches.
Any comments or objections?

Conflict resolution patch attached,

--Sunil
  

Patch

diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
index b573966966..0400ea332b 100644
--- a/sysdeps/x86_64/multiarch/Makefile
+++ b/sysdeps/x86_64/multiarch/Makefile
@@ -11,7 +11,6 @@  sysdep_routines += \
   memcmp-avx2-movbe-rtm \
   memcmp-evex-movbe \
   memcmp-sse2 \
-  memcmp-sse4 \
   memcmpeq-avx2 \
   memcmpeq-avx2-rtm \
   memcmpeq-evex \
@@ -164,7 +163,6 @@  sysdep_routines += \
   wmemcmp-avx2-movbe-rtm \
   wmemcmp-evex-movbe \
   wmemcmp-sse2 \
-  wmemcmp-sse4 \
 # sysdep_routines
 endif
 
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index c6008a73ed..a8afcf81bb 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -96,8 +96,6 @@  __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 			       && CPU_FEATURE_USABLE (BMI2)
 			       && CPU_FEATURE_USABLE (MOVBE)),
 			      __memcmp_evex_movbe)
-	      IFUNC_IMPL_ADD (array, i, memcmp, CPU_FEATURE_USABLE (SSE4_1),
-			      __memcmp_sse4_1)
 	      IFUNC_IMPL_ADD (array, i, memcmp, 1, __memcmp_sse2))
 
 #ifdef SHARED
@@ -809,8 +807,6 @@  __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 			       && CPU_FEATURE_USABLE (BMI2)
 			       && CPU_FEATURE_USABLE (MOVBE)),
 			      __wmemcmp_evex_movbe)
-	      IFUNC_IMPL_ADD (array, i, wmemcmp, CPU_FEATURE_USABLE (SSE4_1),
-			      __wmemcmp_sse4_1)
 	      IFUNC_IMPL_ADD (array, i, wmemcmp, 1, __wmemcmp_sse2))
 
   /* Support sysdeps/x86_64/multiarch/wmemset.c.  */
diff --git a/sysdeps/x86_64/multiarch/ifunc-memcmp.h b/sysdeps/x86_64/multiarch/ifunc-memcmp.h
index 44759a3ad5..c743970fe3 100644
--- a/sysdeps/x86_64/multiarch/ifunc-memcmp.h
+++ b/sysdeps/x86_64/multiarch/ifunc-memcmp.h
@@ -20,7 +20,6 @@ 
 # include <init-arch.h>
 
 extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
-extern __typeof (REDIRECT_NAME) OPTIMIZE (sse4_1) attribute_hidden;
 extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe) attribute_hidden;
 extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_movbe_rtm) attribute_hidden;
 extern __typeof (REDIRECT_NAME) OPTIMIZE (evex_movbe) attribute_hidden;
@@ -46,8 +45,5 @@  IFUNC_SELECTOR (void)
 	return OPTIMIZE (avx2_movbe);
     }
 
-  if (CPU_FEATURE_USABLE_P (cpu_features, SSE4_1))
-    return OPTIMIZE (sse4_1);
-
   return OPTIMIZE (sse2);
 }
diff --git a/sysdeps/x86_64/multiarch/memcmp-sse4.S b/sysdeps/x86_64/multiarch/memcmp-sse4.S
deleted file mode 100644
index cd57c1e2c7..0000000000
--- a/sysdeps/x86_64/multiarch/memcmp-sse4.S
+++ /dev/null
@@ -1,803 +0,0 @@ 
-/* memcmp with SSE4.1, wmemcmp with SSE4.1
-   Copyright (C) 2010-2022 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#if IS_IN (libc)
-
-# include <sysdep.h>
-
-# ifndef MEMCMP
-#  define MEMCMP	__memcmp_sse4_1
-# endif
-
-#ifdef USE_AS_WMEMCMP
-# define CMPEQ	pcmpeqd
-# define CHAR_SIZE	4
-#else
-# define CMPEQ	pcmpeqb
-# define CHAR_SIZE	1
-#endif
-
-
-/* Warning!
-           wmemcmp has to use SIGNED comparison for elements.
-           memcmp has to use UNSIGNED comparison for elemnts.
-*/
-
-	.section .text.sse4.1,"ax",@progbits
-ENTRY (MEMCMP)
-# ifdef USE_AS_WMEMCMP
-	shl	$2, %RDX_LP
-# elif defined __ILP32__
-	/* Clear the upper 32 bits.  */
-	mov	%edx, %edx
-# endif
-	cmp	$79, %RDX_LP
-	ja	L(79bytesormore)
-
-	cmp	$CHAR_SIZE, %RDX_LP
-	jbe	L(firstbyte)
-
-	/* N in (CHAR_SIZE, 79) bytes.  */
-	cmpl	$32, %edx
-	ja	L(more_32_bytes)
-
-	cmpl	$16, %edx
-	jae	L(16_to_32_bytes)
-
-# ifndef USE_AS_WMEMCMP
-	cmpl	$8, %edx
-	jae	L(8_to_16_bytes)
-
-	cmpl	$4, %edx
-	jb	L(2_to_3_bytes)
-
-	movl	(%rdi), %eax
-	movl	(%rsi), %ecx
-
-	bswap	%eax
-	bswap	%ecx
-
-	shlq	$32, %rax
-	shlq	$32, %rcx
-
-	movl	-4(%rdi, %rdx), %edi
-	movl	-4(%rsi, %rdx), %esi
-
-	bswap	%edi
-	bswap	%esi
-
-	orq	%rdi, %rax
-	orq	%rsi, %rcx
-	subq	%rcx, %rax
-	cmovne	%edx, %eax
-	sbbl	%ecx, %ecx
-	orl	%ecx, %eax
-	ret
-
-	.p2align 4,, 8
-L(2_to_3_bytes):
-	movzwl	(%rdi), %eax
-	movzwl	(%rsi), %ecx
-	shll	$8, %eax
-	shll	$8, %ecx
-	bswap	%eax
-	bswap	%ecx
-	movzbl	-1(%rdi, %rdx), %edi
-	movzbl	-1(%rsi, %rdx), %esi
-	orl	%edi, %eax
-	orl	%esi, %ecx
-	subl	%ecx, %eax
-	ret
-
-	.p2align 4,, 8
-L(8_to_16_bytes):
-	movq	(%rdi), %rax
-	movq	(%rsi), %rcx
-
-	bswap	%rax
-	bswap	%rcx
-
-	subq	%rcx, %rax
-	jne	L(8_to_16_bytes_done)
-
-	movq	-8(%rdi, %rdx), %rax
-	movq	-8(%rsi, %rdx), %rcx
-
-	bswap	%rax
-	bswap	%rcx
-
-	subq	%rcx, %rax
-
-L(8_to_16_bytes_done):
-	cmovne	%edx, %eax
-	sbbl	%ecx, %ecx
-	orl	%ecx, %eax
-	ret
-# else
-	xorl	%eax, %eax
-	movl	(%rdi), %ecx
-	cmpl	(%rsi), %ecx
-	jne	L(8_to_16_bytes_done)
-	movl	4(%rdi), %ecx
-	cmpl	4(%rsi), %ecx
-	jne	L(8_to_16_bytes_done)
-	movl	-4(%rdi, %rdx), %ecx
-	cmpl	-4(%rsi, %rdx), %ecx
-	jne	L(8_to_16_bytes_done)
-	ret
-# endif
-
-	.p2align 4,, 3
-L(ret_zero):
-	xorl	%eax, %eax
-L(zero):
-	ret
-
-	.p2align 4,, 8
-L(firstbyte):
-	jb	L(ret_zero)
-# ifdef USE_AS_WMEMCMP
-	xorl	%eax, %eax
-	movl	(%rdi), %ecx
-	cmpl	(%rsi), %ecx
-	je	L(zero)
-L(8_to_16_bytes_done):
-	setg	%al
-	leal	-1(%rax, %rax), %eax
-# else
-	movzbl	(%rdi), %eax
-	movzbl	(%rsi), %ecx
-	sub	%ecx, %eax
-# endif
-	ret
-
-	.p2align 4
-L(vec_return_begin_48):
-	addq	$16, %rdi
-	addq	$16, %rsi
-L(vec_return_begin_32):
-	bsfl	%eax, %eax
-# ifdef USE_AS_WMEMCMP
-	movl	32(%rdi, %rax), %ecx
-	xorl	%edx, %edx
-	cmpl	32(%rsi, %rax), %ecx
-	setg	%dl
-	leal	-1(%rdx, %rdx), %eax
-# else
-	movzbl	32(%rsi, %rax), %ecx
-	movzbl	32(%rdi, %rax), %eax
-	subl	%ecx, %eax
-# endif
-	ret
-
-	.p2align 4
-L(vec_return_begin_16):
-	addq	$16, %rdi
-	addq	$16, %rsi
-L(vec_return_begin):
-	bsfl	%eax, %eax
-# ifdef USE_AS_WMEMCMP
-	movl	(%rdi, %rax), %ecx
-	xorl	%edx, %edx
-	cmpl	(%rsi, %rax), %ecx
-	setg	%dl
-	leal	-1(%rdx, %rdx), %eax
-# else
-	movzbl	(%rsi, %rax), %ecx
-	movzbl	(%rdi, %rax), %eax
-	subl	%ecx, %eax
-# endif
-	ret
-
-	.p2align 4
-L(vec_return_end_16):
-	subl	$16, %edx
-L(vec_return_end):
-	bsfl	%eax, %eax
-	addl	%edx, %eax
-# ifdef USE_AS_WMEMCMP
-	movl	-16(%rdi, %rax), %ecx
-	xorl	%edx, %edx
-	cmpl	-16(%rsi, %rax), %ecx
-	setg	%dl
-	leal	-1(%rdx, %rdx), %eax
-# else
-	movzbl	-16(%rsi, %rax), %ecx
-	movzbl	-16(%rdi, %rax), %eax
-	subl	%ecx, %eax
-# endif
-	ret
-
-	.p2align 4,, 8
-L(more_32_bytes):
-	movdqu	(%rdi), %xmm0
-	movdqu	(%rsi), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-	movdqu	16(%rdi), %xmm0
-	movdqu	16(%rsi), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_16)
-
-	cmpl	$64, %edx
-	jbe	L(32_to_64_bytes)
-	movdqu	32(%rdi), %xmm0
-	movdqu	32(%rsi), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_32)
-
-	.p2align 4,, 6
-L(32_to_64_bytes):
-	movdqu	-32(%rdi, %rdx), %xmm0
-	movdqu	-32(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end_16)
-
-	movdqu	-16(%rdi, %rdx), %xmm0
-	movdqu	-16(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end)
-	ret
-
-	.p2align 4
-L(16_to_32_bytes):
-	movdqu	(%rdi), %xmm0
-	movdqu	(%rsi), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-	movdqu	-16(%rdi, %rdx), %xmm0
-	movdqu	-16(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end)
-	ret
-
-
-	.p2align 4
-L(79bytesormore):
-	movdqu	(%rdi), %xmm0
-	movdqu	(%rsi), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-
-	mov	%rsi, %rcx
-	and	$-16, %rsi
-	add	$16, %rsi
-	sub	%rsi, %rcx
-
-	sub	%rcx, %rdi
-	add	%rcx, %rdx
-	test	$0xf, %rdi
-	jz	L(2aligned)
-
-	cmp	$128, %rdx
-	ja	L(128bytesormore)
-
-	.p2align 4,, 6
-L(less128bytes):
-	movdqu	(%rdi), %xmm1
-	CMPEQ	(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-	movdqu	16(%rdi), %xmm1
-	CMPEQ	16(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_16)
-
-	movdqu	32(%rdi), %xmm1
-	CMPEQ	32(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_32)
-
-	movdqu	48(%rdi), %xmm1
-	CMPEQ	48(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_48)
-
-	cmp	$96, %rdx
-	jb	L(32_to_64_bytes)
-
-	addq	$64, %rdi
-	addq	$64, %rsi
-	subq	$64, %rdx
-
-	.p2align 4,, 6
-L(last_64_bytes):
-	movdqu	(%rdi), %xmm1
-	CMPEQ	(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-	movdqu	16(%rdi), %xmm1
-	CMPEQ	16(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_16)
-
-	movdqu	-32(%rdi, %rdx), %xmm0
-	movdqu	-32(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end_16)
-
-	movdqu	-16(%rdi, %rdx), %xmm0
-	movdqu	-16(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end)
-	ret
-
-	.p2align 4
-L(128bytesormore):
-	cmp	$256, %rdx
-	ja	L(unaligned_loop)
-L(less256bytes):
-	movdqu	(%rdi), %xmm1
-	CMPEQ	(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-	movdqu	16(%rdi), %xmm1
-	CMPEQ	16(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_16)
-
-	movdqu	32(%rdi), %xmm1
-	CMPEQ	32(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_32)
-
-	movdqu	48(%rdi), %xmm1
-	CMPEQ	48(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_48)
-
-	addq	$64, %rdi
-	addq	$64, %rsi
-
-	movdqu	(%rdi), %xmm1
-	CMPEQ	(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-	movdqu	16(%rdi), %xmm1
-	CMPEQ	16(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_16)
-
-	movdqu	32(%rdi), %xmm1
-	CMPEQ	32(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_32)
-
-	movdqu	48(%rdi), %xmm1
-	CMPEQ	48(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_48)
-
-	addq	$-128, %rdx
-	subq	$-64, %rsi
-	subq	$-64, %rdi
-
-	cmp	$64, %rdx
-	ja	L(less128bytes)
-
-	cmp	$32, %rdx
-	ja	L(last_64_bytes)
-
-	movdqu	-32(%rdi, %rdx), %xmm0
-	movdqu	-32(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end_16)
-
-	movdqu	-16(%rdi, %rdx), %xmm0
-	movdqu	-16(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end)
-	ret
-
-	.p2align 4
-L(unaligned_loop):
-# ifdef DATA_CACHE_SIZE_HALF
-	mov	$DATA_CACHE_SIZE_HALF, %R8_LP
-# else
-	mov	__x86_data_cache_size_half(%rip), %R8_LP
-# endif
-	movq	%r8, %r9
-	addq	%r8, %r8
-	addq	%r9, %r8
-	cmpq	%r8, %rdx
-	ja	L(L2_L3_cache_unaligned)
-	sub	$64, %rdx
-	.p2align 4
-L(64bytesormore_loop):
-	movdqu	(%rdi), %xmm0
-	movdqu	16(%rdi), %xmm1
-	movdqu	32(%rdi), %xmm2
-	movdqu	48(%rdi), %xmm3
-
-	CMPEQ	(%rsi), %xmm0
-	CMPEQ	16(%rsi), %xmm1
-	CMPEQ	32(%rsi), %xmm2
-	CMPEQ	48(%rsi), %xmm3
-
-	pand	%xmm0, %xmm1
-	pand	%xmm2, %xmm3
-	pand	%xmm1, %xmm3
-
-	pmovmskb %xmm3, %eax
-	incw	%ax
-	jnz	L(64bytesormore_loop_end)
-
-	add	$64, %rsi
-	add	$64, %rdi
-	sub	$64, %rdx
-	ja	L(64bytesormore_loop)
-
-	.p2align 4,, 6
-L(loop_tail):
-	addq	%rdx, %rdi
-	movdqu	(%rdi), %xmm0
-	movdqu	16(%rdi), %xmm1
-	movdqu	32(%rdi), %xmm2
-	movdqu	48(%rdi), %xmm3
-
-	addq	%rdx, %rsi
-	movdqu	(%rsi), %xmm4
-	movdqu	16(%rsi), %xmm5
-	movdqu	32(%rsi), %xmm6
-	movdqu	48(%rsi), %xmm7
-
-	CMPEQ	%xmm4, %xmm0
-	CMPEQ	%xmm5, %xmm1
-	CMPEQ	%xmm6, %xmm2
-	CMPEQ	%xmm7, %xmm3
-
-	pand	%xmm0, %xmm1
-	pand	%xmm2, %xmm3
-	pand	%xmm1, %xmm3
-
-	pmovmskb %xmm3, %eax
-	incw	%ax
-	jnz	L(64bytesormore_loop_end)
-	ret
-
-L(L2_L3_cache_unaligned):
-	subq	$64, %rdx
-	.p2align 4
-L(L2_L3_unaligned_128bytes_loop):
-	prefetchnta 0x1c0(%rdi)
-	prefetchnta 0x1c0(%rsi)
-
-	movdqu	(%rdi), %xmm0
-	movdqu	16(%rdi), %xmm1
-	movdqu	32(%rdi), %xmm2
-	movdqu	48(%rdi), %xmm3
-
-	CMPEQ	(%rsi), %xmm0
-	CMPEQ	16(%rsi), %xmm1
-	CMPEQ	32(%rsi), %xmm2
-	CMPEQ	48(%rsi), %xmm3
-
-	pand	%xmm0, %xmm1
-	pand	%xmm2, %xmm3
-	pand	%xmm1, %xmm3
-
-	pmovmskb %xmm3, %eax
-	incw	%ax
-	jnz	L(64bytesormore_loop_end)
-
-	add	$64, %rsi
-	add	$64, %rdi
-	sub	$64, %rdx
-	ja	L(L2_L3_unaligned_128bytes_loop)
-	jmp	L(loop_tail)
-
-
-	/* This case is for machines which are sensitive for unaligned
-	 * instructions.  */
-	.p2align 4
-L(2aligned):
-	cmp	$128, %rdx
-	ja	L(128bytesormorein2aligned)
-L(less128bytesin2aligned):
-	movdqa	(%rdi), %xmm1
-	CMPEQ	(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-	movdqa	16(%rdi), %xmm1
-	CMPEQ	16(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_16)
-
-	movdqa	32(%rdi), %xmm1
-	CMPEQ	32(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_32)
-
-	movdqa	48(%rdi), %xmm1
-	CMPEQ	48(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_48)
-
-	cmp	$96, %rdx
-	jb	L(32_to_64_bytes)
-
-	addq	$64, %rdi
-	addq	$64, %rsi
-	subq	$64, %rdx
-
-	.p2align 4,, 6
-L(aligned_last_64_bytes):
-	movdqa	(%rdi), %xmm1
-	CMPEQ	(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-	movdqa	16(%rdi), %xmm1
-	CMPEQ	16(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_16)
-
-	movdqu	-32(%rdi, %rdx), %xmm0
-	movdqu	-32(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end_16)
-
-	movdqu	-16(%rdi, %rdx), %xmm0
-	movdqu	-16(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end)
-	ret
-
-	.p2align 4
-L(128bytesormorein2aligned):
-	cmp	$256, %rdx
-	ja	L(aligned_loop)
-L(less256bytesin2alinged):
-	movdqa	(%rdi), %xmm1
-	CMPEQ	(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-	movdqa	16(%rdi), %xmm1
-	CMPEQ	16(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_16)
-
-	movdqa	32(%rdi), %xmm1
-	CMPEQ	32(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_32)
-
-	movdqa	48(%rdi), %xmm1
-	CMPEQ	48(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_48)
-
-	addq	$64, %rdi
-	addq	$64, %rsi
-
-	movdqa	(%rdi), %xmm1
-	CMPEQ	(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin)
-
-	movdqa	16(%rdi), %xmm1
-	CMPEQ	16(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_16)
-
-	movdqa	32(%rdi), %xmm1
-	CMPEQ	32(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_32)
-
-	movdqa	48(%rdi), %xmm1
-	CMPEQ	48(%rsi), %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_begin_48)
-
-	addq	$-128, %rdx
-	subq	$-64, %rsi
-	subq	$-64, %rdi
-
-	cmp	$64, %rdx
-	ja	L(less128bytesin2aligned)
-
-	cmp	$32, %rdx
-	ja	L(aligned_last_64_bytes)
-
-	movdqu	-32(%rdi, %rdx), %xmm0
-	movdqu	-32(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end_16)
-
-	movdqu	-16(%rdi, %rdx), %xmm0
-	movdqu	-16(%rsi, %rdx), %xmm1
-	CMPEQ	%xmm0, %xmm1
-	pmovmskb %xmm1, %eax
-	incw	%ax
-	jnz	L(vec_return_end)
-	ret
-
-	.p2align 4
-L(aligned_loop):
-# ifdef DATA_CACHE_SIZE_HALF
-	mov	$DATA_CACHE_SIZE_HALF, %R8_LP
-# else
-	mov	__x86_data_cache_size_half(%rip), %R8_LP
-# endif
-	movq	%r8, %r9
-	addq	%r8, %r8
-	addq	%r9, %r8
-	cmpq	%r8, %rdx
-	ja	L(L2_L3_cache_aligned)
-
-	sub	$64, %rdx
-	.p2align 4
-L(64bytesormore_loopin2aligned):
-	movdqa	(%rdi), %xmm0
-	movdqa	16(%rdi), %xmm1
-	movdqa	32(%rdi), %xmm2
-	movdqa	48(%rdi), %xmm3
-
-	CMPEQ	(%rsi), %xmm0
-	CMPEQ	16(%rsi), %xmm1
-	CMPEQ	32(%rsi), %xmm2
-	CMPEQ	48(%rsi), %xmm3
-
-	pand	%xmm0, %xmm1
-	pand	%xmm2, %xmm3
-	pand	%xmm1, %xmm3
-
-	pmovmskb %xmm3, %eax
-	incw	%ax
-	jnz	L(64bytesormore_loop_end)
-	add	$64, %rsi
-	add	$64, %rdi
-	sub	$64, %rdx
-	ja	L(64bytesormore_loopin2aligned)
-	jmp	L(loop_tail)
-
-L(L2_L3_cache_aligned):
-	subq	$64, %rdx
-	.p2align 4
-L(L2_L3_aligned_128bytes_loop):
-	prefetchnta 0x1c0(%rdi)
-	prefetchnta 0x1c0(%rsi)
-	movdqa	(%rdi), %xmm0
-	movdqa	16(%rdi), %xmm1
-	movdqa	32(%rdi), %xmm2
-	movdqa	48(%rdi), %xmm3
-
-	CMPEQ	(%rsi), %xmm0
-	CMPEQ	16(%rsi), %xmm1
-	CMPEQ	32(%rsi), %xmm2
-	CMPEQ	48(%rsi), %xmm3
-
-	pand	%xmm0, %xmm1
-	pand	%xmm2, %xmm3
-	pand	%xmm1, %xmm3
-
-	pmovmskb %xmm3, %eax
-	incw	%ax
-	jnz	L(64bytesormore_loop_end)
-
-	addq	$64, %rsi
-	addq	$64, %rdi
-	subq	$64, %rdx
-	ja	L(L2_L3_aligned_128bytes_loop)
-	jmp	L(loop_tail)
-
-	.p2align 4
-L(64bytesormore_loop_end):
-	pmovmskb %xmm0, %ecx
-	incw	%cx
-	jnz	L(loop_end_ret)
-
-	pmovmskb %xmm1, %ecx
-	notw	%cx
-	sall	$16, %ecx
-	jnz	L(loop_end_ret)
-
-	pmovmskb %xmm2, %ecx
-	notw	%cx
-	shlq	$32, %rcx
-	jnz	L(loop_end_ret)
-
-	addq	$48, %rdi
-	addq	$48, %rsi
-	movq	%rax, %rcx
-
-	.p2align 4,, 6
-L(loop_end_ret):
-	bsfq	%rcx, %rcx
-# ifdef USE_AS_WMEMCMP
-	movl	(%rdi, %rcx), %eax
-	xorl	%edx, %edx
-	cmpl	(%rsi, %rcx), %eax
-	setg	%dl
-	leal	-1(%rdx, %rdx), %eax
-# else
-	movzbl	(%rdi, %rcx), %eax
-	movzbl	(%rsi, %rcx), %ecx
-	subl	%ecx, %eax
-# endif
-	ret
-END (MEMCMP)
-#endif