[PATCH v8 2/2] x86: Add support for compiling {raw|w}memchr with high ISA level

H.J. Lu hjl.tools@gmail.com
Wed Jun 22 17:50:04 GMT 2022


On Wed, Jun 22, 2022 at 10:12 AM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> 1. Refactor files so that all implementations for in the multiarch
>    directory.
>     - Essentially moved sse2 {raw|w}memchr.S implementation to
>       multiarch/{raw|w}memchr-sse2.S
>
>     - The non-multiarch {raw|w}memchr.S file now only includes one of
>       the implementations in the multiarch directory based on the
>       compiled ISA level (only used for non-multiarch builds.
>       Otherwise we go through the ifunc selector).
>
> 2. Add ISA level build guards to different implementations.
>     - I.e memchr-avx2.S which is ISA level 3 will only build if
>       compiled ISA level <= 3. Otherwise there is no reason to include
>       it as we will always use one of the ISA level 4
>       implementations (memchr-evex{-rtm}.S).
>
> 3. Add new multiarch/rtld-{raw}memchr.S that just include the
>    non-multiarch {raw}memchr.S which will in turn select the best
>    implementation based on the compiled ISA level.
>
> 4. Refactor the ifunc selector and ifunc implementation list to use
>    the ISA level aware wrapper macros that allow functions below the
>    compiled ISA level (with a guranteed replacement) to be skipped.
>     - Guranteed replacement essentially means that for any ISA level
>       build there must be a function that the baseline of the ISA
>       supports. So for {raw|w}memchr.S since there is not ISA level 2
>       function, the ISA level 2 build still includes the ISA level
>       1 (sse2) function. Once we reach the ISA level 3 build, however,
>       {raw|w}memchr-avx2{-rtm}.S will always be sufficient so the ISA
>       level 1 implementation ({raw|w}memchr-sse2.S) will not be built.
>
> Tested with and without multiarch on x86_64 for ISA levels:
> {generic, x86-64-v2, x86-64-v3, x86-64-v4}
> ---
>  sysdeps/x86_64/memchr.S                       | 355 +----------------
>  sysdeps/x86_64/multiarch/ifunc-evex.h         |  31 +-
>  sysdeps/x86_64/multiarch/ifunc-impl-list.c    |  72 ++--
>  sysdeps/x86_64/multiarch/memchr-avx2.S        |  10 +-
>  sysdeps/x86_64/multiarch/memchr-evex.S        |  10 +-
>  sysdeps/x86_64/multiarch/memchr-sse2.S        | 368 +++++++++++++++++-
>  sysdeps/x86_64/multiarch/rawmemchr-avx2-rtm.S |   7 +-
>  sysdeps/x86_64/multiarch/rawmemchr-avx2.S     |   7 +-
>  sysdeps/x86_64/multiarch/rawmemchr-evex-rtm.S |   8 +-
>  sysdeps/x86_64/multiarch/rawmemchr-evex.S     |   7 +-
>  sysdeps/x86_64/multiarch/rawmemchr-sse2.S     | 203 +++++++++-
>  sysdeps/x86_64/multiarch/rtld-memchr.S        |  18 +
>  sysdeps/x86_64/multiarch/rtld-rawmemchr.S     |  18 +
>  sysdeps/x86_64/multiarch/wmemchr-avx2-rtm.S   |   7 +-
>  sysdeps/x86_64/multiarch/wmemchr-avx2.S       |   7 +-
>  sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S   |   8 +-
>  sysdeps/x86_64/multiarch/wmemchr-evex.S       |   7 +-
>  sysdeps/x86_64/multiarch/wmemchr-sse2.S       |  27 +-
>  sysdeps/x86_64/rawmemchr.S                    | 186 +--------
>  sysdeps/x86_64/wmemchr.S                      |  24 ++
>  20 files changed, 773 insertions(+), 607 deletions(-)
>  create mode 100644 sysdeps/x86_64/multiarch/rtld-memchr.S
>  create mode 100644 sysdeps/x86_64/multiarch/rtld-rawmemchr.S
>  create mode 100644 sysdeps/x86_64/wmemchr.S
>
> diff --git a/sysdeps/x86_64/memchr.S b/sysdeps/x86_64/memchr.S
> index a160fd9b00..018bb06f04 100644
> --- a/sysdeps/x86_64/memchr.S
> +++ b/sysdeps/x86_64/memchr.S
> @@ -15,358 +15,13 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> -#include <sysdep.h>
> +#define MEMCHR memchr
>
> -#ifdef USE_AS_WMEMCHR
> -# define MEMCHR                wmemchr
> -# define PCMPEQ                pcmpeqd
> -# define CHAR_PER_VEC  4
> -#else
> -# define MEMCHR                memchr
> -# define PCMPEQ                pcmpeqb
> -# define CHAR_PER_VEC  16
> -#endif
> +#define DEFAULT_IMPL_V1        "multiarch/memchr-sse2.S"
> +#define DEFAULT_IMPL_V3        "multiarch/memchr-avx2.S"
> +#define DEFAULT_IMPL_V4        "multiarch/memchr-evex.S"
>
> -/* fast SSE2 version with using pmaxub and 64 byte loop */
> +#include "isa-default-impl.h"
>
> -       .text
> -ENTRY(MEMCHR)
> -       movd    %esi, %xmm1
> -       mov     %edi, %ecx
> -
> -#ifdef __ILP32__
> -       /* Clear the upper 32 bits.  */
> -       movl    %edx, %edx
> -#endif
> -#ifdef USE_AS_WMEMCHR
> -       test    %RDX_LP, %RDX_LP
> -       jz      L(return_null)
> -#else
> -       punpcklbw %xmm1, %xmm1
> -       test    %RDX_LP, %RDX_LP
> -       jz      L(return_null)
> -       punpcklbw %xmm1, %xmm1
> -#endif
> -
> -       and     $63, %ecx
> -       pshufd  $0, %xmm1, %xmm1
> -
> -       cmp     $48, %ecx
> -       ja      L(crosscache)
> -
> -       movdqu  (%rdi), %xmm0
> -       PCMPEQ  %xmm1, %xmm0
> -       pmovmskb %xmm0, %eax
> -       test    %eax, %eax
> -
> -       jnz     L(matches_1)
> -       sub     $CHAR_PER_VEC, %rdx
> -       jbe     L(return_null)
> -       add     $16, %rdi
> -       and     $15, %ecx
> -       and     $-16, %rdi
> -#ifdef USE_AS_WMEMCHR
> -       shr     $2, %ecx
> -#endif
> -       add     %rcx, %rdx
> -       sub     $(CHAR_PER_VEC * 4), %rdx
> -       jbe     L(exit_loop)
> -       jmp     L(loop_prolog)
> -
> -       .p2align 4
> -L(crosscache):
> -       and     $15, %ecx
> -       and     $-16, %rdi
> -       movdqa  (%rdi), %xmm0
> -
> -       PCMPEQ  %xmm1, %xmm0
> -       /* Check if there is a match.  */
> -       pmovmskb %xmm0, %eax
> -       /* Remove the leading bytes.  */
> -       sar     %cl, %eax
> -       test    %eax, %eax
> -       je      L(unaligned_no_match)
> -       /* Check which byte is a match.  */
> -       bsf     %eax, %eax
> -#ifdef USE_AS_WMEMCHR
> -       mov     %eax, %esi
> -       shr     $2, %esi
> -       sub     %rsi, %rdx
> -#else
> -       sub     %rax, %rdx
> -#endif
> -       jbe     L(return_null)
> -       add     %rdi, %rax
> -       add     %rcx, %rax
> -       ret
> -
> -       .p2align 4
> -L(unaligned_no_match):
> -       /* "rcx" is less than 16.  Calculate "rdx + rcx - 16" by using
> -          "rdx - (16 - rcx)" instead of "(rdx + rcx) - 16" to void
> -          possible addition overflow.  */
> -       neg     %rcx
> -       add     $16, %rcx
> -#ifdef USE_AS_WMEMCHR
> -       shr     $2, %ecx
> -#endif
> -       sub     %rcx, %rdx
> -       jbe     L(return_null)
> -       add     $16, %rdi
> -       sub     $(CHAR_PER_VEC * 4), %rdx
> -       jbe     L(exit_loop)
> -
> -       .p2align 4
> -L(loop_prolog):
> -       movdqa  (%rdi), %xmm0
> -       PCMPEQ  %xmm1, %xmm0
> -       pmovmskb %xmm0, %eax
> -       test    %eax, %eax
> -       jnz     L(matches)
> -
> -       movdqa  16(%rdi), %xmm2
> -       PCMPEQ  %xmm1, %xmm2
> -       pmovmskb %xmm2, %eax
> -       test    %eax, %eax
> -       jnz     L(matches16)
> -
> -       movdqa  32(%rdi), %xmm3
> -       PCMPEQ  %xmm1, %xmm3
> -       pmovmskb %xmm3, %eax
> -       test    %eax, %eax
> -       jnz     L(matches32)
> -
> -       movdqa  48(%rdi), %xmm4
> -       PCMPEQ  %xmm1, %xmm4
> -       add     $64, %rdi
> -       pmovmskb %xmm4, %eax
> -       test    %eax, %eax
> -       jnz     L(matches0)
> -
> -       test    $0x3f, %rdi
> -       jz      L(align64_loop)
> -
> -       sub     $(CHAR_PER_VEC * 4), %rdx
> -       jbe     L(exit_loop)
> -
> -       movdqa  (%rdi), %xmm0
> -       PCMPEQ  %xmm1, %xmm0
> -       pmovmskb %xmm0, %eax
> -       test    %eax, %eax
> -       jnz     L(matches)
> -
> -       movdqa  16(%rdi), %xmm2
> -       PCMPEQ  %xmm1, %xmm2
> -       pmovmskb %xmm2, %eax
> -       test    %eax, %eax
> -       jnz     L(matches16)
> -
> -       movdqa  32(%rdi), %xmm3
> -       PCMPEQ  %xmm1, %xmm3
> -       pmovmskb %xmm3, %eax
> -       test    %eax, %eax
> -       jnz     L(matches32)
> -
> -       movdqa  48(%rdi), %xmm3
> -       PCMPEQ  %xmm1, %xmm3
> -       pmovmskb %xmm3, %eax
> -
> -       add     $64, %rdi
> -       test    %eax, %eax
> -       jnz     L(matches0)
> -
> -       mov     %rdi, %rcx
> -       and     $-64, %rdi
> -       and     $63, %ecx
> -#ifdef USE_AS_WMEMCHR
> -       shr     $2, %ecx
> -#endif
> -       add     %rcx, %rdx
> -
> -       .p2align 4
> -L(align64_loop):
> -       sub     $(CHAR_PER_VEC * 4), %rdx
> -       jbe     L(exit_loop)
> -       movdqa  (%rdi), %xmm0
> -       movdqa  16(%rdi), %xmm2
> -       movdqa  32(%rdi), %xmm3
> -       movdqa  48(%rdi), %xmm4
> -
> -       PCMPEQ  %xmm1, %xmm0
> -       PCMPEQ  %xmm1, %xmm2
> -       PCMPEQ  %xmm1, %xmm3
> -       PCMPEQ  %xmm1, %xmm4
> -
> -       pmaxub  %xmm0, %xmm3
> -       pmaxub  %xmm2, %xmm4
> -       pmaxub  %xmm3, %xmm4
> -       pmovmskb %xmm4, %eax
> -
> -       add     $64, %rdi
> -
> -       test    %eax, %eax
> -       jz      L(align64_loop)
> -
> -       sub     $64, %rdi
> -
> -       pmovmskb %xmm0, %eax
> -       test    %eax, %eax
> -       jnz     L(matches)
> -
> -       pmovmskb %xmm2, %eax
> -       test    %eax, %eax
> -       jnz     L(matches16)
> -
> -       movdqa  32(%rdi), %xmm3
> -       PCMPEQ  %xmm1, %xmm3
> -
> -       PCMPEQ  48(%rdi), %xmm1
> -       pmovmskb %xmm3, %eax
> -       test    %eax, %eax
> -       jnz     L(matches32)
> -
> -       pmovmskb %xmm1, %eax
> -       bsf     %eax, %eax
> -       lea     48(%rdi, %rax), %rax
> -       ret
> -
> -       .p2align 4
> -L(exit_loop):
> -       add     $(CHAR_PER_VEC * 2), %edx
> -       jle     L(exit_loop_32)
> -
> -       movdqa  (%rdi), %xmm0
> -       PCMPEQ  %xmm1, %xmm0
> -       pmovmskb %xmm0, %eax
> -       test    %eax, %eax
> -       jnz     L(matches)
> -
> -       movdqa  16(%rdi), %xmm2
> -       PCMPEQ  %xmm1, %xmm2
> -       pmovmskb %xmm2, %eax
> -       test    %eax, %eax
> -       jnz     L(matches16)
> -
> -       movdqa  32(%rdi), %xmm3
> -       PCMPEQ  %xmm1, %xmm3
> -       pmovmskb %xmm3, %eax
> -       test    %eax, %eax
> -       jnz     L(matches32_1)
> -       sub     $CHAR_PER_VEC, %edx
> -       jle     L(return_null)
> -
> -       PCMPEQ  48(%rdi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       test    %eax, %eax
> -       jnz     L(matches48_1)
> -       xor     %eax, %eax
> -       ret
> -
> -       .p2align 4
> -L(exit_loop_32):
> -       add     $(CHAR_PER_VEC * 2), %edx
> -       movdqa  (%rdi), %xmm0
> -       PCMPEQ  %xmm1, %xmm0
> -       pmovmskb %xmm0, %eax
> -       test    %eax, %eax
> -       jnz     L(matches_1)
> -       sub     $CHAR_PER_VEC, %edx
> -       jbe     L(return_null)
> -
> -       PCMPEQ  16(%rdi), %xmm1
> -       pmovmskb %xmm1, %eax
> -       test    %eax, %eax
> -       jnz     L(matches16_1)
> -       xor     %eax, %eax
> -       ret
> -
> -       .p2align 4
> -L(matches0):
> -       bsf     %eax, %eax
> -       lea     -16(%rax, %rdi), %rax
> -       ret
> -
> -       .p2align 4
> -L(matches):
> -       bsf     %eax, %eax
> -       add     %rdi, %rax
> -       ret
> -
> -       .p2align 4
> -L(matches16):
> -       bsf     %eax, %eax
> -       lea     16(%rax, %rdi), %rax
> -       ret
> -
> -       .p2align 4
> -L(matches32):
> -       bsf     %eax, %eax
> -       lea     32(%rax, %rdi), %rax
> -       ret
> -
> -       .p2align 4
> -L(matches_1):
> -       bsf     %eax, %eax
> -#ifdef USE_AS_WMEMCHR
> -       mov     %eax, %esi
> -       shr     $2, %esi
> -       sub     %rsi, %rdx
> -#else
> -       sub     %rax, %rdx
> -#endif
> -       jbe     L(return_null)
> -       add     %rdi, %rax
> -       ret
> -
> -       .p2align 4
> -L(matches16_1):
> -       bsf     %eax, %eax
> -#ifdef USE_AS_WMEMCHR
> -       mov     %eax, %esi
> -       shr     $2, %esi
> -       sub     %rsi, %rdx
> -#else
> -       sub     %rax, %rdx
> -#endif
> -       jbe     L(return_null)
> -       lea     16(%rdi, %rax), %rax
> -       ret
> -
> -       .p2align 4
> -L(matches32_1):
> -       bsf     %eax, %eax
> -#ifdef USE_AS_WMEMCHR
> -       mov     %eax, %esi
> -       shr     $2, %esi
> -       sub     %rsi, %rdx
> -#else
> -       sub     %rax, %rdx
> -#endif
> -       jbe     L(return_null)
> -       lea     32(%rdi, %rax), %rax
> -       ret
> -
> -       .p2align 4
> -L(matches48_1):
> -       bsf     %eax, %eax
> -#ifdef USE_AS_WMEMCHR
> -       mov     %eax, %esi
> -       shr     $2, %esi
> -       sub     %rsi, %rdx
> -#else
> -       sub     %rax, %rdx
> -#endif
> -       jbe     L(return_null)
> -       lea     48(%rdi, %rax), %rax
> -       ret
> -
> -       .p2align 4
> -L(return_null):
> -       xor     %eax, %eax
> -       ret
> -END(MEMCHR)
> -
> -#ifndef USE_AS_WMEMCHR
>  strong_alias (memchr, __memchr)
>  libc_hidden_builtin_def(memchr)
> -#endif
> diff --git a/sysdeps/x86_64/multiarch/ifunc-evex.h b/sysdeps/x86_64/multiarch/ifunc-evex.h
> index b8f7a12ea2..a2f854b98d 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-evex.h
> +++ b/sysdeps/x86_64/multiarch/ifunc-evex.h
> @@ -19,24 +19,28 @@
>
>  #include <init-arch.h>
>
> -extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;
> -extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
> -extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_rtm) attribute_hidden;
>  extern __typeof (REDIRECT_NAME) OPTIMIZE (evex) attribute_hidden;
>  extern __typeof (REDIRECT_NAME) OPTIMIZE (evex_rtm) attribute_hidden;
>
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_rtm) attribute_hidden;
>
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (sse2) attribute_hidden;

Unrelated changes.

> +/* TODO: Look into using the ISA build level to remove some/all of the
> +   feature checks.  */

This comment should be removed.

>  static inline void *
>  IFUNC_SELECTOR (void)
>  {
> -  const struct cpu_features* cpu_features = __get_cpu_features ();
> +  const struct cpu_features *cpu_features = __get_cpu_features ();
>
> -  if (CPU_FEATURE_USABLE_P (cpu_features, AVX2)
> -      && CPU_FEATURE_USABLE_P (cpu_features, BMI2)
> -      && CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
> +  if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX2)
> +      && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, BMI2)
> +      && X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
> +                                     AVX_Fast_Unaligned_Load))
>      {
> -      if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
> -         && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
> +      if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
> +         && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
>         {
>           if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
>             return OPTIMIZE (evex_rtm);
> @@ -44,12 +48,19 @@ IFUNC_SELECTOR (void)
>           return OPTIMIZE (evex);
>         }
>
> +      X86_ERROR_IF_REACHABLE_V4 ();
> +
>        if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
>         return OPTIMIZE (avx2_rtm);
>
> -      if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
> +      if (X86_ISA_CPU_FEATURES_ARCH_P (cpu_features,
> +                                      Prefer_No_VZEROUPPER))
>         return OPTIMIZE (avx2);
>      }
>
> +  X86_ERROR_IF_REACHABLE_V3 ();
> +
> +  /* This is unreachable (compile time checked) if ISA level >= 3
> +     so no need for a robust fallback here.  */
>    return OPTIMIZE (sse2);
>  }
> diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> index 883362f63d..bf52cf96d0 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> @@ -25,7 +25,8 @@
>
>  /* Fill ARRAY of MAX elements with IFUNC implementations for function
>     NAME supported on target machine and return the number of valid
> -   entries.  */
> +   entries.  Each set of implementations for a given function is sorted in
> +   descending order by ISA level.  */
>
>  size_t
>  __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> @@ -53,24 +54,27 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>
>    /* Support sysdeps/x86_64/multiarch/memchr.c.  */
>    IFUNC_IMPL (i, name, memchr,
> -             IFUNC_IMPL_ADD (array, i, memchr,
> -                             CPU_FEATURE_USABLE (AVX2),
> -                             __memchr_avx2)
> -             IFUNC_IMPL_ADD (array, i, memchr,
> -                             (CPU_FEATURE_USABLE (AVX2)
> -                              && CPU_FEATURE_USABLE (RTM)),
> -                             __memchr_avx2_rtm)
> -             IFUNC_IMPL_ADD (array, i, memchr,
> +             X86_IFUNC_IMPL_ADD_V4 (array, i, memchr,
>                               (CPU_FEATURE_USABLE (AVX512VL)
>                                && CPU_FEATURE_USABLE (AVX512BW)
>                                && CPU_FEATURE_USABLE (BMI2)),
>                               __memchr_evex)
> -             IFUNC_IMPL_ADD (array, i, memchr,
> +             X86_IFUNC_IMPL_ADD_V4 (array, i, memchr,
>                               (CPU_FEATURE_USABLE (AVX512VL)
>                                && CPU_FEATURE_USABLE (AVX512BW)
>                                && CPU_FEATURE_USABLE (BMI2)),
>                               __memchr_evex_rtm)
> -             IFUNC_IMPL_ADD (array, i, memchr, 1, __memchr_sse2))
> +             X86_IFUNC_IMPL_ADD_V3 (array, i, memchr,
> +                             CPU_FEATURE_USABLE (AVX2),
> +                             __memchr_avx2)
> +             X86_IFUNC_IMPL_ADD_V3 (array, i, memchr,
> +                             (CPU_FEATURE_USABLE (AVX2)
> +                              && CPU_FEATURE_USABLE (RTM)),
> +                             __memchr_avx2_rtm)
> +             /* Can be lowered to V1 if a V2 implementation is added.  */
> +             X86_IFUNC_IMPL_ADD_V2 (array, i, memchr,
> +                             1,
> +                             __memchr_sse2))
>
>    /* Support sysdeps/x86_64/multiarch/memcmp.c.  */
>    IFUNC_IMPL (i, name, memcmp,
> @@ -288,24 +292,27 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>
>    /* Support sysdeps/x86_64/multiarch/rawmemchr.c.  */
>    IFUNC_IMPL (i, name, rawmemchr,
> -             IFUNC_IMPL_ADD (array, i, rawmemchr,
> -                             CPU_FEATURE_USABLE (AVX2),
> -                             __rawmemchr_avx2)
> -             IFUNC_IMPL_ADD (array, i, rawmemchr,
> -                             (CPU_FEATURE_USABLE (AVX2)
> -                              && CPU_FEATURE_USABLE (RTM)),
> -                             __rawmemchr_avx2_rtm)
> -             IFUNC_IMPL_ADD (array, i, rawmemchr,
> +             X86_IFUNC_IMPL_ADD_V4 (array, i, rawmemchr,
>                               (CPU_FEATURE_USABLE (AVX512VL)
>                                && CPU_FEATURE_USABLE (AVX512BW)
>                                && CPU_FEATURE_USABLE (BMI2)),
>                               __rawmemchr_evex)
> -             IFUNC_IMPL_ADD (array, i, rawmemchr,
> +             X86_IFUNC_IMPL_ADD_V4 (array, i, rawmemchr,
>                               (CPU_FEATURE_USABLE (AVX512VL)
>                                && CPU_FEATURE_USABLE (AVX512BW)
>                                && CPU_FEATURE_USABLE (BMI2)),
>                               __rawmemchr_evex_rtm)
> -             IFUNC_IMPL_ADD (array, i, rawmemchr, 1, __rawmemchr_sse2))
> +             X86_IFUNC_IMPL_ADD_V3 (array, i, rawmemchr,
> +                             CPU_FEATURE_USABLE (AVX2),
> +                             __rawmemchr_avx2)
> +             X86_IFUNC_IMPL_ADD_V3 (array, i, rawmemchr,
> +                             (CPU_FEATURE_USABLE (AVX2)
> +                              && CPU_FEATURE_USABLE (RTM)),
> +                             __rawmemchr_avx2_rtm)
> +             /* Can be lowered to V1 if a V2 implementation is added.  */
> +             X86_IFUNC_IMPL_ADD_V2 (array, i, rawmemchr,
> +                             1,
> +                             __rawmemchr_sse2))
>
>    /* Support sysdeps/x86_64/multiarch/strlen.c.  */
>    IFUNC_IMPL (i, name, strlen,
> @@ -748,24 +755,27 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>
>    /* Support sysdeps/x86_64/multiarch/wmemchr.c.  */
>    IFUNC_IMPL (i, name, wmemchr,
> -             IFUNC_IMPL_ADD (array, i, wmemchr,
> -                             CPU_FEATURE_USABLE (AVX2),
> -                             __wmemchr_avx2)
> -             IFUNC_IMPL_ADD (array, i, wmemchr,
> -                             (CPU_FEATURE_USABLE (AVX2)
> -                              && CPU_FEATURE_USABLE (RTM)),
> -                             __wmemchr_avx2_rtm)
> -             IFUNC_IMPL_ADD (array, i, wmemchr,
> +             X86_IFUNC_IMPL_ADD_V4 (array, i, wmemchr,
>                               (CPU_FEATURE_USABLE (AVX512VL)
>                                && CPU_FEATURE_USABLE (AVX512BW)
>                                && CPU_FEATURE_USABLE (BMI2)),
>                               __wmemchr_evex)
> -             IFUNC_IMPL_ADD (array, i, wmemchr,
> +             X86_IFUNC_IMPL_ADD_V4 (array, i, wmemchr,
>                               (CPU_FEATURE_USABLE (AVX512VL)
>                                && CPU_FEATURE_USABLE (AVX512BW)
>                                && CPU_FEATURE_USABLE (BMI2)),
>                               __wmemchr_evex_rtm)
> -             IFUNC_IMPL_ADD (array, i, wmemchr, 1, __wmemchr_sse2))
> +             X86_IFUNC_IMPL_ADD_V3 (array, i, wmemchr,
> +                             CPU_FEATURE_USABLE (AVX2),
> +                             __wmemchr_avx2)
> +             X86_IFUNC_IMPL_ADD_V3 (array, i, wmemchr,
> +                             (CPU_FEATURE_USABLE (AVX2)
> +                              && CPU_FEATURE_USABLE (RTM)),
> +                             __wmemchr_avx2_rtm)
> +             /* Can be lowered to V1 if a V2 implementation is added.  */
> +             X86_IFUNC_IMPL_ADD_V2 (array, i, wmemchr,
> +                             1,
> +                             __wmemchr_sse2))
>
>    /* Support sysdeps/x86_64/multiarch/wmemcmp.c.  */
>    IFUNC_IMPL (i, name, wmemcmp,
> diff --git a/sysdeps/x86_64/multiarch/memchr-avx2.S b/sysdeps/x86_64/multiarch/memchr-avx2.S
> index c5a256eb37..691662f0fb 100644
> --- a/sysdeps/x86_64/multiarch/memchr-avx2.S
> +++ b/sysdeps/x86_64/multiarch/memchr-avx2.S
> @@ -16,7 +16,15 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> -#if IS_IN (libc)
> +#include <isa-level.h>
> +
> +#if defined IS_MULTIARCH && defined ISA_DEFAULT_IMPL

Where is  IS_MULTIARCH defined?


> +# error "Multiarch build should never default include!"
> +#endif
> +
> +#if (MINIMUM_X86_ISA_LEVEL <= 3 && IS_IN (libc)) \
> +       || defined ISA_DEFAULT_IMPL
> +
>
>  # include <sysdep.h>
>
> diff --git a/sysdeps/x86_64/multiarch/memchr-evex.S b/sysdeps/x86_64/multiarch/memchr-evex.S
> index 0fd11b7632..10ed0434ae 100644
> --- a/sysdeps/x86_64/multiarch/memchr-evex.S
> +++ b/sysdeps/x86_64/multiarch/memchr-evex.S
> @@ -16,7 +16,15 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> -#if IS_IN (libc)
> +#include <isa-level.h>
> +
> +#if defined IS_MULTIARCH && defined ISA_DEFAULT_IMPL
> +# error "Multiarch build should never default include!"
> +#endif
> +
> +#if (MINIMUM_X86_ISA_LEVEL <= 4 && IS_IN (libc)) \
> +       || defined ISA_DEFAULT_IMPL
> +
>
>  # include <sysdep.h>
>
> diff --git a/sysdeps/x86_64/multiarch/memchr-sse2.S b/sysdeps/x86_64/multiarch/memchr-sse2.S
> index 2c6fdd41d6..acd5c15e22 100644
> --- a/sysdeps/x86_64/multiarch/memchr-sse2.S
> +++ b/sysdeps/x86_64/multiarch/memchr-sse2.S
> @@ -16,13 +16,367 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> -#if IS_IN (libc)
> -# define memchr __memchr_sse2
> +#include <isa-level.h>
>
> -# undef strong_alias
> -# define strong_alias(memchr, __memchr)
> -# undef libc_hidden_builtin_def
> -# define libc_hidden_builtin_def(memchr)
> +#if defined IS_MULTIARCH && defined ISA_DEFAULT_IMPL
> +# error "Multiarch build should never default include!"
>  #endif
>
> -#include "../memchr.S"
> +/* __X86_ISA_LEVEL <= 2 because there is no V2 implementation so we
> +   need this to build for ISA V2 builds. */
> +#if (MINIMUM_X86_ISA_LEVEL <= 2 && IS_IN (libc)) \
> +       || defined ISA_DEFAULT_IMPL
> +
> +
> +# include <sysdep.h>
> +
> +# ifndef MEMCHR
> +#  define MEMCHR       __memchr_sse2
> +# endif
> +# ifdef USE_AS_WMEMCHR
> +#  define PCMPEQ               pcmpeqd
> +#  define CHAR_PER_VEC 4
> +# else
> +#  define PCMPEQ               pcmpeqb
> +#  define CHAR_PER_VEC 16
> +# endif
> +
> +/* fast SSE2 version with using pmaxub and 64 byte loop */
> +
> +       .text
> +ENTRY(MEMCHR)
> +       movd    %esi, %xmm1
> +       mov     %edi, %ecx
> +
> +# ifdef __ILP32__
> +       /* Clear the upper 32 bits.  */
> +       movl    %edx, %edx
> +# endif
> +# ifdef USE_AS_WMEMCHR
> +       test    %RDX_LP, %RDX_LP
> +       jz      L(return_null)
> +# else
> +       punpcklbw %xmm1, %xmm1
> +       test    %RDX_LP, %RDX_LP
> +       jz      L(return_null)
> +       punpcklbw %xmm1, %xmm1
> +# endif
> +
> +       and     $63, %ecx
> +       pshufd  $0, %xmm1, %xmm1
> +
> +       cmp     $48, %ecx
> +       ja      L(crosscache)
> +
> +       movdqu  (%rdi), %xmm0
> +       PCMPEQ  %xmm1, %xmm0
> +       pmovmskb %xmm0, %eax
> +       test    %eax, %eax
> +
> +       jnz     L(matches_1)
> +       sub     $CHAR_PER_VEC, %rdx
> +       jbe     L(return_null)
> +       add     $16, %rdi
> +       and     $15, %ecx
> +       and     $-16, %rdi
> +# ifdef USE_AS_WMEMCHR
> +       shr     $2, %ecx
> +# endif
> +       add     %rcx, %rdx
> +       sub     $(CHAR_PER_VEC * 4), %rdx
> +       jbe     L(exit_loop)
> +       jmp     L(loop_prolog)
> +
> +       .p2align 4
> +L(crosscache):
> +       and     $15, %ecx
> +       and     $-16, %rdi
> +       movdqa  (%rdi), %xmm0
> +
> +       PCMPEQ  %xmm1, %xmm0
> +       /* Check if there is a match.  */
> +       pmovmskb %xmm0, %eax
> +       /* Remove the leading bytes.  */
> +       sar     %cl, %eax
> +       test    %eax, %eax
> +       je      L(unaligned_no_match)
> +       /* Check which byte is a match.  */
> +       bsf     %eax, %eax
> +# ifdef USE_AS_WMEMCHR
> +       mov     %eax, %esi
> +       shr     $2, %esi
> +       sub     %rsi, %rdx
> +# else
> +       sub     %rax, %rdx
> +# endif
> +       jbe     L(return_null)
> +       add     %rdi, %rax
> +       add     %rcx, %rax
> +       ret
> +
> +       .p2align 4
> +L(unaligned_no_match):
> +       /* "rcx" is less than 16.  Calculate "rdx + rcx - 16" by using
> +          "rdx - (16 - rcx)" instead of "(rdx + rcx) - 16" to void
> +          possible addition overflow.  */
> +       neg     %rcx
> +       add     $16, %rcx
> +# ifdef USE_AS_WMEMCHR
> +       shr     $2, %ecx
> +# endif
> +       sub     %rcx, %rdx
> +       jbe     L(return_null)
> +       add     $16, %rdi
> +       sub     $(CHAR_PER_VEC * 4), %rdx
> +       jbe     L(exit_loop)
> +
> +       .p2align 4
> +L(loop_prolog):
> +       movdqa  (%rdi), %xmm0
> +       PCMPEQ  %xmm1, %xmm0
> +       pmovmskb %xmm0, %eax
> +       test    %eax, %eax
> +       jnz     L(matches)
> +
> +       movdqa  16(%rdi), %xmm2
> +       PCMPEQ  %xmm1, %xmm2
> +       pmovmskb %xmm2, %eax
> +       test    %eax, %eax
> +       jnz     L(matches16)
> +
> +       movdqa  32(%rdi), %xmm3
> +       PCMPEQ  %xmm1, %xmm3
> +       pmovmskb %xmm3, %eax
> +       test    %eax, %eax
> +       jnz     L(matches32)
> +
> +       movdqa  48(%rdi), %xmm4
> +       PCMPEQ  %xmm1, %xmm4
> +       add     $64, %rdi
> +       pmovmskb %xmm4, %eax
> +       test    %eax, %eax
> +       jnz     L(matches0)
> +
> +       test    $0x3f, %rdi
> +       jz      L(align64_loop)
> +
> +       sub     $(CHAR_PER_VEC * 4), %rdx
> +       jbe     L(exit_loop)
> +
> +       movdqa  (%rdi), %xmm0
> +       PCMPEQ  %xmm1, %xmm0
> +       pmovmskb %xmm0, %eax
> +       test    %eax, %eax
> +       jnz     L(matches)
> +
> +       movdqa  16(%rdi), %xmm2
> +       PCMPEQ  %xmm1, %xmm2
> +       pmovmskb %xmm2, %eax
> +       test    %eax, %eax
> +       jnz     L(matches16)
> +
> +       movdqa  32(%rdi), %xmm3
> +       PCMPEQ  %xmm1, %xmm3
> +       pmovmskb %xmm3, %eax
> +       test    %eax, %eax
> +       jnz     L(matches32)
> +
> +       movdqa  48(%rdi), %xmm3
> +       PCMPEQ  %xmm1, %xmm3
> +       pmovmskb %xmm3, %eax
> +
> +       add     $64, %rdi
> +       test    %eax, %eax
> +       jnz     L(matches0)
> +
> +       mov     %rdi, %rcx
> +       and     $-64, %rdi
> +       and     $63, %ecx
> +# ifdef USE_AS_WMEMCHR
> +       shr     $2, %ecx
> +# endif
> +       add     %rcx, %rdx
> +
> +       .p2align 4
> +L(align64_loop):
> +       sub     $(CHAR_PER_VEC * 4), %rdx
> +       jbe     L(exit_loop)
> +       movdqa  (%rdi), %xmm0
> +       movdqa  16(%rdi), %xmm2
> +       movdqa  32(%rdi), %xmm3
> +       movdqa  48(%rdi), %xmm4
> +
> +       PCMPEQ  %xmm1, %xmm0
> +       PCMPEQ  %xmm1, %xmm2
> +       PCMPEQ  %xmm1, %xmm3
> +       PCMPEQ  %xmm1, %xmm4
> +
> +       pmaxub  %xmm0, %xmm3
> +       pmaxub  %xmm2, %xmm4
> +       pmaxub  %xmm3, %xmm4
> +       pmovmskb %xmm4, %eax
> +
> +       add     $64, %rdi
> +
> +       test    %eax, %eax
> +       jz      L(align64_loop)
> +
> +       sub     $64, %rdi
> +
> +       pmovmskb %xmm0, %eax
> +       test    %eax, %eax
> +       jnz     L(matches)
> +
> +       pmovmskb %xmm2, %eax
> +       test    %eax, %eax
> +       jnz     L(matches16)
> +
> +       movdqa  32(%rdi), %xmm3
> +       PCMPEQ  %xmm1, %xmm3
> +
> +       PCMPEQ  48(%rdi), %xmm1
> +       pmovmskb %xmm3, %eax
> +       test    %eax, %eax
> +       jnz     L(matches32)
> +
> +       pmovmskb %xmm1, %eax
> +       bsf     %eax, %eax
> +       lea     48(%rdi, %rax), %rax
> +       ret
> +
> +       .p2align 4
> +L(exit_loop):
> +       add     $(CHAR_PER_VEC * 2), %edx
> +       jle     L(exit_loop_32)
> +
> +       movdqa  (%rdi), %xmm0
> +       PCMPEQ  %xmm1, %xmm0
> +       pmovmskb %xmm0, %eax
> +       test    %eax, %eax
> +       jnz     L(matches)
> +
> +       movdqa  16(%rdi), %xmm2
> +       PCMPEQ  %xmm1, %xmm2
> +       pmovmskb %xmm2, %eax
> +       test    %eax, %eax
> +       jnz     L(matches16)
> +
> +       movdqa  32(%rdi), %xmm3
> +       PCMPEQ  %xmm1, %xmm3
> +       pmovmskb %xmm3, %eax
> +       test    %eax, %eax
> +       jnz     L(matches32_1)
> +       sub     $CHAR_PER_VEC, %edx
> +       jle     L(return_null)
> +
> +       PCMPEQ  48(%rdi), %xmm1
> +       pmovmskb %xmm1, %eax
> +       test    %eax, %eax
> +       jnz     L(matches48_1)
> +       xor     %eax, %eax
> +       ret
> +
> +       .p2align 4
> +L(exit_loop_32):
> +       add     $(CHAR_PER_VEC * 2), %edx
> +       movdqa  (%rdi), %xmm0
> +       PCMPEQ  %xmm1, %xmm0
> +       pmovmskb %xmm0, %eax
> +       test    %eax, %eax
> +       jnz     L(matches_1)
> +       sub     $CHAR_PER_VEC, %edx
> +       jbe     L(return_null)
> +
> +       PCMPEQ  16(%rdi), %xmm1
> +       pmovmskb %xmm1, %eax
> +       test    %eax, %eax
> +       jnz     L(matches16_1)
> +       xor     %eax, %eax
> +       ret
> +
> +       .p2align 4
> +L(matches0):
> +       bsf     %eax, %eax
> +       lea     -16(%rax, %rdi), %rax
> +       ret
> +
> +       .p2align 4
> +L(matches):
> +       bsf     %eax, %eax
> +       add     %rdi, %rax
> +       ret
> +
> +       .p2align 4
> +L(matches16):
> +       bsf     %eax, %eax
> +       lea     16(%rax, %rdi), %rax
> +       ret
> +
> +       .p2align 4
> +L(matches32):
> +       bsf     %eax, %eax
> +       lea     32(%rax, %rdi), %rax
> +       ret
> +
> +       .p2align 4
> +L(matches_1):
> +       bsf     %eax, %eax
> +# ifdef USE_AS_WMEMCHR
> +       mov     %eax, %esi
> +       shr     $2, %esi
> +       sub     %rsi, %rdx
> +# else
> +       sub     %rax, %rdx
> +# endif
> +       jbe     L(return_null)
> +       add     %rdi, %rax
> +       ret
> +
> +       .p2align 4
> +L(matches16_1):
> +       bsf     %eax, %eax
> +# ifdef USE_AS_WMEMCHR
> +       mov     %eax, %esi
> +       shr     $2, %esi
> +       sub     %rsi, %rdx
> +# else
> +       sub     %rax, %rdx
> +# endif
> +       jbe     L(return_null)
> +       lea     16(%rdi, %rax), %rax
> +       ret
> +
> +       .p2align 4
> +L(matches32_1):
> +       bsf     %eax, %eax
> +# ifdef USE_AS_WMEMCHR
> +       mov     %eax, %esi
> +       shr     $2, %esi
> +       sub     %rsi, %rdx
> +# else
> +       sub     %rax, %rdx
> +# endif
> +       jbe     L(return_null)
> +       lea     32(%rdi, %rax), %rax
> +       ret
> +
> +       .p2align 4
> +L(matches48_1):
> +       bsf     %eax, %eax
> +# ifdef USE_AS_WMEMCHR
> +       mov     %eax, %esi
> +       shr     $2, %esi
> +       sub     %rsi, %rdx
> +# else
> +       sub     %rax, %rdx
> +# endif
> +       jbe     L(return_null)
> +       lea     48(%rdi, %rax), %rax
> +       ret
> +
> +       .p2align 4
> +L(return_null):
> +       xor     %eax, %eax
> +       ret
> +END(MEMCHR)
> +#endif
> diff --git a/sysdeps/x86_64/multiarch/rawmemchr-avx2-rtm.S b/sysdeps/x86_64/multiarch/rawmemchr-avx2-rtm.S
> index acc5f6e2fb..5c1dcd3ca7 100644
> --- a/sysdeps/x86_64/multiarch/rawmemchr-avx2-rtm.S
> +++ b/sysdeps/x86_64/multiarch/rawmemchr-avx2-rtm.S
> @@ -1,4 +1,7 @@
> -#define MEMCHR __rawmemchr_avx2_rtm
> -#define USE_AS_RAWMEMCHR 1
> +#ifndef RAWMEMCHR
> +# define RAWMEMCHR     __rawmemchr_avx2_rtm
> +#endif
> +#define USE_AS_RAWMEMCHR       1
> +#define MEMCHR RAWMEMCHR
>
>  #include "memchr-avx2-rtm.S"
> diff --git a/sysdeps/x86_64/multiarch/rawmemchr-avx2.S b/sysdeps/x86_64/multiarch/rawmemchr-avx2.S
> index 128f9ea637..d6bff28757 100644
> --- a/sysdeps/x86_64/multiarch/rawmemchr-avx2.S
> +++ b/sysdeps/x86_64/multiarch/rawmemchr-avx2.S
> @@ -1,4 +1,7 @@
> -#define MEMCHR __rawmemchr_avx2
> -#define USE_AS_RAWMEMCHR 1
> +#ifndef RAWMEMCHR
> +# define RAWMEMCHR     __rawmemchr_avx2
> +#endif
> +#define USE_AS_RAWMEMCHR       1
> +#define MEMCHR RAWMEMCHR
>
>  #include "memchr-avx2.S"
> diff --git a/sysdeps/x86_64/multiarch/rawmemchr-evex-rtm.S b/sysdeps/x86_64/multiarch/rawmemchr-evex-rtm.S
> index deda1ca395..8ff7f27c9c 100644
> --- a/sysdeps/x86_64/multiarch/rawmemchr-evex-rtm.S
> +++ b/sysdeps/x86_64/multiarch/rawmemchr-evex-rtm.S
> @@ -1,3 +1,7 @@
> -#define MEMCHR __rawmemchr_evex_rtm
> -#define USE_AS_RAWMEMCHR 1
> +#ifndef RAWMEMCHR
> +# define RAWMEMCHR     __rawmemchr_evex_rtm
> +#endif
> +#define USE_AS_RAWMEMCHR       1
> +#define MEMCHR RAWMEMCHR
> +
>  #include "memchr-evex-rtm.S"
> diff --git a/sysdeps/x86_64/multiarch/rawmemchr-evex.S b/sysdeps/x86_64/multiarch/rawmemchr-evex.S
> index ec942b77ba..dc1c450699 100644
> --- a/sysdeps/x86_64/multiarch/rawmemchr-evex.S
> +++ b/sysdeps/x86_64/multiarch/rawmemchr-evex.S
> @@ -1,4 +1,7 @@
> -#define MEMCHR __rawmemchr_evex
> -#define USE_AS_RAWMEMCHR 1
> +#ifndef RAWMEMCHR
> +# define RAWMEMCHR     __rawmemchr_evex
> +#endif
> +#define USE_AS_RAWMEMCHR       1
> +#define MEMCHR RAWMEMCHR
>
>  #include "memchr-evex.S"
> diff --git a/sysdeps/x86_64/multiarch/rawmemchr-sse2.S b/sysdeps/x86_64/multiarch/rawmemchr-sse2.S
> index 3841c14c34..73f4fa9589 100644
> --- a/sysdeps/x86_64/multiarch/rawmemchr-sse2.S
> +++ b/sysdeps/x86_64/multiarch/rawmemchr-sse2.S
> @@ -16,14 +16,199 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> -/* Define multiple versions only for the definition in libc. */
> -#if IS_IN (libc)
> -# define __rawmemchr __rawmemchr_sse2
> -
> -# undef weak_alias
> -# define weak_alias(__rawmemchr, rawmemchr)
> -# undef libc_hidden_def
> -# define libc_hidden_def(__rawmemchr)
> +#include <isa-level.h>
> +
> +#if defined IS_MULTIARCH && defined ISA_DEFAULT_IMPL
> +# error "Multiarch build should never default include!"
>  #endif
>
> -#include "../rawmemchr.S"
> +/* __X86_ISA_LEVEL <= 2 because there is no V2 implementation so we
> +   need this to build for ISA V2 builds. */
> +#if (MINIMUM_X86_ISA_LEVEL <= 2 && IS_IN (libc)) \
> +       || defined ISA_DEFAULT_IMPL
> +
> +
> +# include <sysdep.h>
> +
> +# ifndef RAWMEMCHR
> +#  define RAWMEMCHR    __rawmemchr_sse2
> +# endif
> +
> +       .text
> +ENTRY (RAWMEMCHR)
> +       movd    %rsi, %xmm1
> +       mov     %rdi, %rcx
> +
> +       punpcklbw %xmm1, %xmm1
> +       punpcklbw %xmm1, %xmm1
> +
> +       and     $63, %rcx
> +       pshufd  $0, %xmm1, %xmm1
> +
> +       cmp     $48, %rcx
> +       ja      L(crosscache)
> +
> +       movdqu  (%rdi), %xmm0
> +       pcmpeqb %xmm1, %xmm0
> +/* Check if there is a match.  */
> +       pmovmskb %xmm0, %eax
> +       test    %eax, %eax
> +
> +       jnz     L(matches)
> +       add     $16, %rdi
> +       and     $-16, %rdi
> +       jmp     L(loop_prolog)
> +
> +       .p2align 4
> +L(crosscache):
> +       and     $15, %rcx
> +       and     $-16, %rdi
> +       movdqa  (%rdi), %xmm0
> +
> +       pcmpeqb %xmm1, %xmm0
> +/* Check if there is a match.  */
> +       pmovmskb %xmm0, %eax
> +/* Remove the leading bytes.  */
> +       sar     %cl, %eax
> +       test    %eax, %eax
> +       je      L(unaligned_no_match)
> +/* Check which byte is a match.  */
> +       bsf     %eax, %eax
> +
> +       add     %rdi, %rax
> +       add     %rcx, %rax
> +       ret
> +
> +       .p2align 4
> +L(unaligned_no_match):
> +       add     $16, %rdi
> +
> +       .p2align 4
> +L(loop_prolog):
> +       movdqa  (%rdi), %xmm0
> +       pcmpeqb %xmm1, %xmm0
> +       pmovmskb %xmm0, %eax
> +       test    %eax, %eax
> +       jnz     L(matches)
> +
> +       movdqa  16(%rdi), %xmm2
> +       pcmpeqb %xmm1, %xmm2
> +       pmovmskb %xmm2, %eax
> +       test    %eax, %eax
> +       jnz     L(matches16)
> +
> +       movdqa  32(%rdi), %xmm3
> +       pcmpeqb %xmm1, %xmm3
> +       pmovmskb %xmm3, %eax
> +       test    %eax, %eax
> +       jnz     L(matches32)
> +
> +       movdqa  48(%rdi), %xmm4
> +       pcmpeqb %xmm1, %xmm4
> +       add     $64, %rdi
> +       pmovmskb %xmm4, %eax
> +       test    %eax, %eax
> +       jnz     L(matches0)
> +
> +       test    $0x3f, %rdi
> +       jz      L(align64_loop)
> +
> +       movdqa  (%rdi), %xmm0
> +       pcmpeqb %xmm1, %xmm0
> +       pmovmskb %xmm0, %eax
> +       test    %eax, %eax
> +       jnz     L(matches)
> +
> +       movdqa  16(%rdi), %xmm2
> +       pcmpeqb %xmm1, %xmm2
> +       pmovmskb %xmm2, %eax
> +       test    %eax, %eax
> +       jnz     L(matches16)
> +
> +       movdqa  32(%rdi), %xmm3
> +       pcmpeqb %xmm1, %xmm3
> +       pmovmskb %xmm3, %eax
> +       test    %eax, %eax
> +       jnz     L(matches32)
> +
> +       movdqa  48(%rdi), %xmm3
> +       pcmpeqb %xmm1, %xmm3
> +       pmovmskb %xmm3, %eax
> +
> +       add     $64, %rdi
> +       test    %eax, %eax
> +       jnz     L(matches0)
> +
> +       and     $-64, %rdi
> +
> +       .p2align 4
> +L(align64_loop):
> +       movdqa  (%rdi), %xmm0
> +       movdqa  16(%rdi), %xmm2
> +       movdqa  32(%rdi), %xmm3
> +       movdqa  48(%rdi), %xmm4
> +
> +       pcmpeqb %xmm1, %xmm0
> +       pcmpeqb %xmm1, %xmm2
> +       pcmpeqb %xmm1, %xmm3
> +       pcmpeqb %xmm1, %xmm4
> +
> +       pmaxub  %xmm0, %xmm3
> +       pmaxub  %xmm2, %xmm4
> +       pmaxub  %xmm3, %xmm4
> +       pmovmskb %xmm4, %eax
> +
> +       add     $64, %rdi
> +
> +       test    %eax, %eax
> +       jz      L(align64_loop)
> +
> +       sub     $64, %rdi
> +
> +       pmovmskb %xmm0, %eax
> +       test    %eax, %eax
> +       jnz     L(matches)
> +
> +       pmovmskb %xmm2, %eax
> +       test    %eax, %eax
> +       jnz     L(matches16)
> +
> +       movdqa  32(%rdi), %xmm3
> +       pcmpeqb %xmm1, %xmm3
> +
> +       pcmpeqb 48(%rdi), %xmm1
> +       pmovmskb %xmm3, %eax
> +       test    %eax, %eax
> +       jnz     L(matches32)
> +
> +       pmovmskb %xmm1, %eax
> +       bsf     %eax, %eax
> +       lea     48(%rdi, %rax), %rax
> +       ret
> +
> +       .p2align 4
> +L(matches0):
> +       bsf     %eax, %eax
> +       lea     -16(%rax, %rdi), %rax
> +       ret
> +
> +       .p2align 4
> +L(matches):
> +       bsf     %eax, %eax
> +       add     %rdi, %rax
> +       ret
> +
> +       .p2align 4
> +L(matches16):
> +       bsf     %eax, %eax
> +       lea     16(%rax, %rdi), %rax
> +       ret
> +
> +       .p2align 4
> +L(matches32):
> +       bsf     %eax, %eax
> +       lea     32(%rax, %rdi), %rax
> +       ret
> +
> +END (RAWMEMCHR)
> +#endif
> diff --git a/sysdeps/x86_64/multiarch/rtld-memchr.S b/sysdeps/x86_64/multiarch/rtld-memchr.S
> new file mode 100644
> index 0000000000..a14b192bed
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/rtld-memchr.S
> @@ -0,0 +1,18 @@
> +/* Copyright (C) 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/>.  */
> +
> +#include "../memchr.S"
> diff --git a/sysdeps/x86_64/multiarch/rtld-rawmemchr.S b/sysdeps/x86_64/multiarch/rtld-rawmemchr.S
> new file mode 100644
> index 0000000000..5d4110a052
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/rtld-rawmemchr.S
> @@ -0,0 +1,18 @@
> +/* Copyright (C) 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/>.  */
> +
> +#include "../rawmemchr.S"
> diff --git a/sysdeps/x86_64/multiarch/wmemchr-avx2-rtm.S b/sysdeps/x86_64/multiarch/wmemchr-avx2-rtm.S
> index 58ed21db01..2a1cff5b05 100644
> --- a/sysdeps/x86_64/multiarch/wmemchr-avx2-rtm.S
> +++ b/sysdeps/x86_64/multiarch/wmemchr-avx2-rtm.S
> @@ -1,4 +1,7 @@
> -#define MEMCHR __wmemchr_avx2_rtm
> -#define USE_AS_WMEMCHR 1
> +#ifndef WMEMCHR
> +# define WMEMCHR       __wmemchr_avx2_rtm
> +#endif
> +#define USE_AS_WMEMCHR 1
> +#define MEMCHR WMEMCHR
>
>  #include "memchr-avx2-rtm.S"
> diff --git a/sysdeps/x86_64/multiarch/wmemchr-avx2.S b/sysdeps/x86_64/multiarch/wmemchr-avx2.S
> index 282854f1a1..2bf93fd84b 100644
> --- a/sysdeps/x86_64/multiarch/wmemchr-avx2.S
> +++ b/sysdeps/x86_64/multiarch/wmemchr-avx2.S
> @@ -1,4 +1,7 @@
> -#define MEMCHR __wmemchr_avx2
> -#define USE_AS_WMEMCHR 1
> +#ifndef WMEMCHR
> +# define WMEMCHR       __wmemchr_avx2
> +#endif
> +#define USE_AS_WMEMCHR 1
> +#define MEMCHR WMEMCHR
>
>  #include "memchr-avx2.S"
> diff --git a/sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S b/sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S
> index a346cd35a1..c67309e8a1 100644
> --- a/sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S
> +++ b/sysdeps/x86_64/multiarch/wmemchr-evex-rtm.S
> @@ -1,3 +1,7 @@
> -#define MEMCHR __wmemchr_evex_rtm
> -#define USE_AS_WMEMCHR 1
> +#ifndef WMEMCHR
> +# define WMEMCHR       __wmemchr_evex_rtm
> +#endif
> +#define USE_AS_WMEMCHR 1
> +#define MEMCHR WMEMCHR
> +
>  #include "memchr-evex-rtm.S"
> diff --git a/sysdeps/x86_64/multiarch/wmemchr-evex.S b/sysdeps/x86_64/multiarch/wmemchr-evex.S
> index 06cd0f9f5a..5512d5cdc3 100644
> --- a/sysdeps/x86_64/multiarch/wmemchr-evex.S
> +++ b/sysdeps/x86_64/multiarch/wmemchr-evex.S
> @@ -1,4 +1,7 @@
> -#define MEMCHR __wmemchr_evex
> -#define USE_AS_WMEMCHR 1
> +#ifndef WMEMCHR
> +# define WMEMCHR       __wmemchr_evex
> +#endif
> +#define USE_AS_WMEMCHR 1
> +#define MEMCHR WMEMCHR
>
>  #include "memchr-evex.S"
> diff --git a/sysdeps/x86_64/multiarch/wmemchr-sse2.S b/sysdeps/x86_64/multiarch/wmemchr-sse2.S
> index 70a965d552..3081fb6821 100644
> --- a/sysdeps/x86_64/multiarch/wmemchr-sse2.S
> +++ b/sysdeps/x86_64/multiarch/wmemchr-sse2.S
> @@ -1,4 +1,25 @@
> -#define USE_AS_WMEMCHR 1
> -#define wmemchr __wmemchr_sse2
> +/* wmemchr optimized with SSE2
> +   Copyright (C) 2022 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
>
> -#include "../memchr.S"
> +   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/>.  */
> +
> +#ifndef WMEMCHR
> +# define WMEMCHR       __wmemchr_sse2
> +#endif
> +#define USE_AS_WMEMCHR 1
> +#define MEMCHR WMEMCHR
> +
> +#include "memchr-sse2.S"
> diff --git a/sysdeps/x86_64/rawmemchr.S b/sysdeps/x86_64/rawmemchr.S
> index 4c1a3383b9..e401a2ac53 100644
> --- a/sysdeps/x86_64/rawmemchr.S
> +++ b/sysdeps/x86_64/rawmemchr.S
> @@ -17,185 +17,13 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>
> -#include <sysdep.h>
> +#define RAWMEMCHR      rawmemchr
>
> -       .text
> -ENTRY (__rawmemchr)
> -       movd    %rsi, %xmm1
> -       mov     %rdi, %rcx
> +#define DEFAULT_IMPL_V1        "multiarch/rawmemchr-sse2.S"
> +#define DEFAULT_IMPL_V3        "multiarch/rawmemchr-avx2.S"
> +#define DEFAULT_IMPL_V4        "multiarch/rawmemchr-evex.S"
>
> -       punpcklbw %xmm1, %xmm1
> -       punpcklbw %xmm1, %xmm1
> +#include "isa-default-impl.h"
>
> -       and     $63, %rcx
> -       pshufd  $0, %xmm1, %xmm1
> -
> -       cmp     $48, %rcx
> -       ja      L(crosscache)
> -
> -       movdqu  (%rdi), %xmm0
> -       pcmpeqb %xmm1, %xmm0
> -/* Check if there is a match.  */
> -       pmovmskb %xmm0, %eax
> -       test    %eax, %eax
> -
> -       jnz     L(matches)
> -       add     $16, %rdi
> -       and     $-16, %rdi
> -       jmp     L(loop_prolog)
> -
> -       .p2align 4
> -L(crosscache):
> -       and     $15, %rcx
> -       and     $-16, %rdi
> -       movdqa  (%rdi), %xmm0
> -
> -       pcmpeqb %xmm1, %xmm0
> -/* Check if there is a match.  */
> -       pmovmskb %xmm0, %eax
> -/* Remove the leading bytes.  */
> -       sar     %cl, %eax
> -       test    %eax, %eax
> -       je      L(unaligned_no_match)
> -/* Check which byte is a match.  */
> -       bsf     %eax, %eax
> -
> -       add     %rdi, %rax
> -       add     %rcx, %rax
> -       ret
> -
> -       .p2align 4
> -L(unaligned_no_match):
> -       add     $16, %rdi
> -
> -       .p2align 4
> -L(loop_prolog):
> -       movdqa  (%rdi), %xmm0
> -       pcmpeqb %xmm1, %xmm0
> -       pmovmskb %xmm0, %eax
> -       test    %eax, %eax
> -       jnz     L(matches)
> -
> -       movdqa  16(%rdi), %xmm2
> -       pcmpeqb %xmm1, %xmm2
> -       pmovmskb %xmm2, %eax
> -       test    %eax, %eax
> -       jnz     L(matches16)
> -
> -       movdqa  32(%rdi), %xmm3
> -       pcmpeqb %xmm1, %xmm3
> -       pmovmskb %xmm3, %eax
> -       test    %eax, %eax
> -       jnz     L(matches32)
> -
> -       movdqa  48(%rdi), %xmm4
> -       pcmpeqb %xmm1, %xmm4
> -       add     $64, %rdi
> -       pmovmskb %xmm4, %eax
> -       test    %eax, %eax
> -       jnz     L(matches0)
> -
> -       test    $0x3f, %rdi
> -       jz      L(align64_loop)
> -
> -       movdqa  (%rdi), %xmm0
> -       pcmpeqb %xmm1, %xmm0
> -       pmovmskb %xmm0, %eax
> -       test    %eax, %eax
> -       jnz     L(matches)
> -
> -       movdqa  16(%rdi), %xmm2
> -       pcmpeqb %xmm1, %xmm2
> -       pmovmskb %xmm2, %eax
> -       test    %eax, %eax
> -       jnz     L(matches16)
> -
> -       movdqa  32(%rdi), %xmm3
> -       pcmpeqb %xmm1, %xmm3
> -       pmovmskb %xmm3, %eax
> -       test    %eax, %eax
> -       jnz     L(matches32)
> -
> -       movdqa  48(%rdi), %xmm3
> -       pcmpeqb %xmm1, %xmm3
> -       pmovmskb %xmm3, %eax
> -
> -       add     $64, %rdi
> -       test    %eax, %eax
> -       jnz     L(matches0)
> -
> -       and     $-64, %rdi
> -
> -       .p2align 4
> -L(align64_loop):
> -       movdqa  (%rdi), %xmm0
> -       movdqa  16(%rdi), %xmm2
> -       movdqa  32(%rdi), %xmm3
> -       movdqa  48(%rdi), %xmm4
> -
> -       pcmpeqb %xmm1, %xmm0
> -       pcmpeqb %xmm1, %xmm2
> -       pcmpeqb %xmm1, %xmm3
> -       pcmpeqb %xmm1, %xmm4
> -
> -       pmaxub  %xmm0, %xmm3
> -       pmaxub  %xmm2, %xmm4
> -       pmaxub  %xmm3, %xmm4
> -       pmovmskb %xmm4, %eax
> -
> -       add     $64, %rdi
> -
> -       test    %eax, %eax
> -       jz      L(align64_loop)
> -
> -       sub     $64, %rdi
> -
> -       pmovmskb %xmm0, %eax
> -       test    %eax, %eax
> -       jnz     L(matches)
> -
> -       pmovmskb %xmm2, %eax
> -       test    %eax, %eax
> -       jnz     L(matches16)
> -
> -       movdqa  32(%rdi), %xmm3
> -       pcmpeqb %xmm1, %xmm3
> -
> -       pcmpeqb 48(%rdi), %xmm1
> -       pmovmskb %xmm3, %eax
> -       test    %eax, %eax
> -       jnz     L(matches32)
> -
> -       pmovmskb %xmm1, %eax
> -       bsf     %eax, %eax
> -       lea     48(%rdi, %rax), %rax
> -       ret
> -
> -       .p2align 4
> -L(matches0):
> -       bsf     %eax, %eax
> -       lea     -16(%rax, %rdi), %rax
> -       ret
> -
> -       .p2align 4
> -L(matches):
> -       bsf     %eax, %eax
> -       add     %rdi, %rax
> -       ret
> -
> -       .p2align 4
> -L(matches16):
> -       bsf     %eax, %eax
> -       lea     16(%rax, %rdi), %rax
> -       ret
> -
> -       .p2align 4
> -L(matches32):
> -       bsf     %eax, %eax
> -       lea     32(%rax, %rdi), %rax
> -       ret
> -
> -END (__rawmemchr)
> -
> -weak_alias (__rawmemchr, rawmemchr)
> -libc_hidden_builtin_def (__rawmemchr)
> +strong_alias (rawmemchr, __rawmemchr)
> +libc_hidden_builtin_def (rawmemchr)
> diff --git a/sysdeps/x86_64/wmemchr.S b/sysdeps/x86_64/wmemchr.S
> new file mode 100644
> index 0000000000..dd0490f86b
> --- /dev/null
> +++ b/sysdeps/x86_64/wmemchr.S
> @@ -0,0 +1,24 @@
> +/* Copyright (C) 2011-2022 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/>.  */
> +
> +#define WMEMCHR        wmemchr
> +
> +#define DEFAULT_IMPL_V1        "multiarch/wmemchr-sse2.S"
> +#define DEFAULT_IMPL_V3        "multiarch/wmemchr-avx2.S"
> +#define DEFAULT_IMPL_V4        "multiarch/wmemchr-evex.S"
> +
> +#include "isa-default-impl.h"
> --
> 2.34.1
>


--
H.J.


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