diff mbox series

[v1,3/6] x86_64: Add support for __memcmpeq using sse2, avx2, and evex

Message ID 20211027024323.1199441-3-goldstein.w.n@gmail.com
State Committed
Commit cf4fd28ea453d1a9cec93939bc88b58ccef5437a
Headers show
Series [v1,1/6] String: Add __memcmpeq as build target | expand

Checks

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

Commit Message

Noah Goldstein Oct. 27, 2021, 2:43 a.m. UTC
No bug. This commit adds support for __memcmpeq to be implemented
seperately from memcmp. Support is added for versions optimized with
sse2, avx2, and evex.
---
 sysdeps/generic/ifunc-init.h                 |  5 +-
 sysdeps/x86_64/memcmp.S                      |  9 ++--
 sysdeps/x86_64/multiarch/Makefile            |  4 ++
 sysdeps/x86_64/multiarch/ifunc-impl-list.c   | 21 +++++++++
 sysdeps/x86_64/multiarch/ifunc-memcmpeq.h    | 49 ++++++++++++++++++++
 sysdeps/x86_64/multiarch/memcmp-sse2.S       |  4 +-
 sysdeps/x86_64/multiarch/memcmp.c            |  3 --
 sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S | 12 +++++
 sysdeps/x86_64/multiarch/memcmpeq-avx2.S     | 23 +++++++++
 sysdeps/x86_64/multiarch/memcmpeq-evex.S     | 23 +++++++++
 sysdeps/x86_64/multiarch/memcmpeq-sse2.S     | 23 +++++++++
 sysdeps/x86_64/multiarch/memcmpeq.c          | 35 ++++++++++++++
 12 files changed, 202 insertions(+), 9 deletions(-)
 create mode 100644 sysdeps/x86_64/multiarch/ifunc-memcmpeq.h
 create mode 100644 sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S
 create mode 100644 sysdeps/x86_64/multiarch/memcmpeq-avx2.S
 create mode 100644 sysdeps/x86_64/multiarch/memcmpeq-evex.S
 create mode 100644 sysdeps/x86_64/multiarch/memcmpeq-sse2.S
 create mode 100644 sysdeps/x86_64/multiarch/memcmpeq.c

Comments

H.J. Lu Oct. 27, 2021, 12:47 p.m. UTC | #1
On Tue, Oct 26, 2021 at 7:43 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> No bug. This commit adds support for __memcmpeq to be implemented
> seperately from memcmp. Support is added for versions optimized with
> sse2, avx2, and evex.
> ---
>  sysdeps/generic/ifunc-init.h                 |  5 +-
>  sysdeps/x86_64/memcmp.S                      |  9 ++--
>  sysdeps/x86_64/multiarch/Makefile            |  4 ++
>  sysdeps/x86_64/multiarch/ifunc-impl-list.c   | 21 +++++++++
>  sysdeps/x86_64/multiarch/ifunc-memcmpeq.h    | 49 ++++++++++++++++++++
>  sysdeps/x86_64/multiarch/memcmp-sse2.S       |  4 +-
>  sysdeps/x86_64/multiarch/memcmp.c            |  3 --
>  sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S | 12 +++++
>  sysdeps/x86_64/multiarch/memcmpeq-avx2.S     | 23 +++++++++
>  sysdeps/x86_64/multiarch/memcmpeq-evex.S     | 23 +++++++++
>  sysdeps/x86_64/multiarch/memcmpeq-sse2.S     | 23 +++++++++
>  sysdeps/x86_64/multiarch/memcmpeq.c          | 35 ++++++++++++++
>  12 files changed, 202 insertions(+), 9 deletions(-)
>  create mode 100644 sysdeps/x86_64/multiarch/ifunc-memcmpeq.h
>  create mode 100644 sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S
>  create mode 100644 sysdeps/x86_64/multiarch/memcmpeq-avx2.S
>  create mode 100644 sysdeps/x86_64/multiarch/memcmpeq-evex.S
>  create mode 100644 sysdeps/x86_64/multiarch/memcmpeq-sse2.S
>  create mode 100644 sysdeps/x86_64/multiarch/memcmpeq.c
>
> diff --git a/sysdeps/generic/ifunc-init.h b/sysdeps/generic/ifunc-init.h
> index 7f69485de8..ee8a8289c8 100644
> --- a/sysdeps/generic/ifunc-init.h
> +++ b/sysdeps/generic/ifunc-init.h
> @@ -50,5 +50,8 @@
>     '__<symbol>_<variant>' as the optimized implementation and
>     '<symbol>_ifunc_selector' as the IFUNC selector.  */
>  #define REDIRECT_NAME  EVALUATOR1 (__redirect, SYMBOL_NAME)
> -#define OPTIMIZE(name) EVALUATOR2 (SYMBOL_NAME, name)
>  #define IFUNC_SELECTOR EVALUATOR1 (SYMBOL_NAME, ifunc_selector)
> +#define OPTIMIZE1(name)        EVALUATOR1 (SYMBOL_NAME, name)
> +#define OPTIMIZE2(name)        EVALUATOR2 (SYMBOL_NAME, name)
> +/* Default is to use OPTIMIZE2.  */
> +#define OPTIMIZE(name) OPTIMIZE2(name)
> diff --git a/sysdeps/x86_64/memcmp.S b/sysdeps/x86_64/memcmp.S
> index 8a03e572e8..b53f2c0866 100644
> --- a/sysdeps/x86_64/memcmp.S
> +++ b/sysdeps/x86_64/memcmp.S
> @@ -356,9 +356,10 @@ L(ATR32res):
>         .p2align 4,, 4
>  END(memcmp)
>
> -#undef bcmp
> +#ifdef USE_AS_MEMCMPEQ
> +libc_hidden_def (memcmp)
> +#else
> +# undef bcmp
>  weak_alias (memcmp, bcmp)
> -#undef __memcmpeq
> -strong_alias (memcmp, __memcmpeq)
>  libc_hidden_builtin_def (memcmp)
> -libc_hidden_def (__memcmpeq)
> +#endif
> diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
> index 26be40959c..044778585b 100644
> --- a/sysdeps/x86_64/multiarch/Makefile
> +++ b/sysdeps/x86_64/multiarch/Makefile
> @@ -7,7 +7,9 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c \
>                    memchr-sse2 rawmemchr-sse2 memchr-avx2 rawmemchr-avx2 \
>                    memrchr-sse2 memrchr-avx2 \
>                    memcmp-sse2 \
> +                  memcmpeq-sse2 \
>                    memcmp-avx2-movbe \
> +                  memcmpeq-avx2 \
>                    memcmp-sse4 memcpy-ssse3 \
>                    memmove-ssse3 \
>                    memcpy-ssse3-back \
> @@ -42,6 +44,7 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c \
>                    memset-avx512-unaligned-erms \
>                    memchr-avx2-rtm \
>                    memcmp-avx2-movbe-rtm \
> +                  memcmpeq-avx2-rtm \
>                    memmove-avx-unaligned-erms-rtm \
>                    memrchr-avx2-rtm \
>                    memset-avx2-unaligned-erms-rtm \
> @@ -61,6 +64,7 @@ sysdep_routines += strncat-c stpncpy-c strncpy-c \
>                    strrchr-avx2-rtm \
>                    memchr-evex \
>                    memcmp-evex-movbe \
> +                  memcmpeq-evex \
>                    memmove-evex-unaligned-erms \
>                    memrchr-evex \
>                    memset-evex-unaligned-erms \
> diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> index 39ab10613b..f7f3806d1d 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> @@ -38,6 +38,27 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>
>    size_t i = 0;
>
> +  /* Support sysdeps/x86_64/multiarch/memcmpeq.c.  */
> +  IFUNC_IMPL (i, name, __memcmpeq,
> +             IFUNC_IMPL_ADD (array, i, __memcmpeq,
> +                             (CPU_FEATURE_USABLE (AVX2)
> +                   && CPU_FEATURE_USABLE (MOVBE)
> +                              && CPU_FEATURE_USABLE (BMI2)),
> +                             __memcmpeq_avx2)
> +             IFUNC_IMPL_ADD (array, i, __memcmpeq,
> +                             (CPU_FEATURE_USABLE (AVX2)
> +                              && CPU_FEATURE_USABLE (BMI2)
> +                   && CPU_FEATURE_USABLE (MOVBE)
> +                              && CPU_FEATURE_USABLE (RTM)),
> +                             __memcmpeq_avx2_rtm)
> +             IFUNC_IMPL_ADD (array, i, __memcmpeq,
> +                             (CPU_FEATURE_USABLE (AVX512VL)
> +                              && CPU_FEATURE_USABLE (AVX512BW)
> +                   && CPU_FEATURE_USABLE (MOVBE)
> +                              && CPU_FEATURE_USABLE (BMI2)),
> +                             __memcmpeq_evex)
> +             IFUNC_IMPL_ADD (array, i, __memcmpeq, 1, __memcmpeq_sse2))
> +
>    /* Support sysdeps/x86_64/multiarch/memchr.c.  */
>    IFUNC_IMPL (i, name, memchr,
>               IFUNC_IMPL_ADD (array, i, memchr,
> diff --git a/sysdeps/x86_64/multiarch/ifunc-memcmpeq.h b/sysdeps/x86_64/multiarch/ifunc-memcmpeq.h
> new file mode 100644
> index 0000000000..3319a9568a
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/ifunc-memcmpeq.h
> @@ -0,0 +1,49 @@
> +/* Common definition for __memcmpeq ifunc selections.
> +   All versions must be listed in ifunc-impl-list.c.
> +   Copyright (C) 2017-2021 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 <init-arch.h>
> +
> +extern __typeof (REDIRECT_NAME) OPTIMIZE1 (sse2) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx2) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx2_rtm) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE1 (evex) attribute_hidden;
> +
> +static inline void *
> +IFUNC_SELECTOR (void)
> +{
> +  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_FEATURE_USABLE_P (cpu_features, MOVBE)
> +      && 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))
> +       return OPTIMIZE1 (evex);
> +
> +      if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
> +       return OPTIMIZE1 (avx2_rtm);
> +
> +      if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
> +       return OPTIMIZE1 (avx2);
> +    }
> +
> +  return OPTIMIZE1 (sse2);
> +}
> diff --git a/sysdeps/x86_64/multiarch/memcmp-sse2.S b/sysdeps/x86_64/multiarch/memcmp-sse2.S
> index 7b30b7ca2e..132d6fb339 100644
> --- a/sysdeps/x86_64/multiarch/memcmp-sse2.S
> +++ b/sysdeps/x86_64/multiarch/memcmp-sse2.S
> @@ -17,7 +17,9 @@
>     <https://www.gnu.org/licenses/>.  */
>
>  #if IS_IN (libc)
> -# define memcmp __memcmp_sse2
> +# ifndef memcmp
> +#  define memcmp __memcmp_sse2
> +# endif
>
>  # ifdef SHARED
>  #  undef libc_hidden_builtin_def
> diff --git a/sysdeps/x86_64/multiarch/memcmp.c b/sysdeps/x86_64/multiarch/memcmp.c
> index 7b3409b1dd..fe725f3563 100644
> --- a/sysdeps/x86_64/multiarch/memcmp.c
> +++ b/sysdeps/x86_64/multiarch/memcmp.c
> @@ -29,9 +29,6 @@
>  libc_ifunc_redirected (__redirect_memcmp, memcmp, IFUNC_SELECTOR ());
>  # undef bcmp
>  weak_alias (memcmp, bcmp)
> -# undef __memcmpeq
> -strong_alias (memcmp, __memcmpeq)
> -libc_hidden_def (__memcmpeq)
>
>  # ifdef SHARED
>  __hidden_ver1 (memcmp, __GI_memcmp, __redirect_memcmp)
> diff --git a/sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S b/sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S
> new file mode 100644
> index 0000000000..24b6a0c9ff
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S
> @@ -0,0 +1,12 @@
> +#ifndef MEMCMP
> +# define MEMCMP __memcmpeq_avx2_rtm
> +#endif
> +
> +#define ZERO_UPPER_VEC_REGISTERS_RETURN \
> +  ZERO_UPPER_VEC_REGISTERS_RETURN_XTEST
> +
> +#define VZEROUPPER_RETURN jmp   L(return_vzeroupper)
> +
> +#define SECTION(p) p##.avx.rtm
> +
> +#include "memcmpeq-avx2.S"
> diff --git a/sysdeps/x86_64/multiarch/memcmpeq-avx2.S b/sysdeps/x86_64/multiarch/memcmpeq-avx2.S
> new file mode 100644
> index 0000000000..0181ea0d8d
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/memcmpeq-avx2.S
> @@ -0,0 +1,23 @@
> +/* __memcmpeq optimized with AVX2.
> +   Copyright (C) 2017-2021 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/>.  */
> +
> +#ifndef MEMCMP
> +# define MEMCMP        __memcmpeq_avx2
> +#endif
> +
> +#include "memcmp-avx2-movbe.S"
> diff --git a/sysdeps/x86_64/multiarch/memcmpeq-evex.S b/sysdeps/x86_64/multiarch/memcmpeq-evex.S
> new file mode 100644
> index 0000000000..951e1e9560
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/memcmpeq-evex.S
> @@ -0,0 +1,23 @@
> +/* __memcmpeq optimized with EVEX.
> +   Copyright (C) 2017-2021 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/>.  */
> +
> +#ifndef MEMCMP
> +# define MEMCMP        __memcmpeq_evex
> +#endif
> +
> +#include "memcmp-evex-movbe.S"
> diff --git a/sysdeps/x86_64/multiarch/memcmpeq-sse2.S b/sysdeps/x86_64/multiarch/memcmpeq-sse2.S
> new file mode 100644
> index 0000000000..c488cbbcd9
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/memcmpeq-sse2.S
> @@ -0,0 +1,23 @@
> +/* __memcmpeq optimized with SSE2.
> +   Copyright (C) 2017-2021 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/>.  */
> +
> +#ifndef memcmp
> +# define memcmp        __memcmpeq_sse2
> +#endif
> +#define USE_AS_MEMCMPEQ        1
> +#include "memcmp-sse2.S"
> diff --git a/sysdeps/x86_64/multiarch/memcmpeq.c b/sysdeps/x86_64/multiarch/memcmpeq.c
> new file mode 100644
> index 0000000000..163e56047e
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/memcmpeq.c
> @@ -0,0 +1,35 @@
> +/* Multiple versions of __memcmpeq.
> +   All versions must be listed in ifunc-impl-list.c.
> +   Copyright (C) 2017-2021 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 multiple versions only for the definition in libc.  */
> +#if IS_IN (libc)
> +# define __memcmpeq __redirect___memcmpeq
> +# include <string.h>
> +# undef __memcmpeq
> +
> +# define SYMBOL_NAME __memcmpeq
> +# include "ifunc-memcmpeq.h"
> +
> +libc_ifunc_redirected (__redirect___memcmpeq, __memcmpeq, IFUNC_SELECTOR ());
> +
> +# ifdef SHARED
> +__hidden_ver1 (__memcmpeq, __GI___memcmpeq, __redirect___memcmpeq)
> +    __attribute__ ((visibility ("hidden"))) __attribute_copy__ (__memcmpeq);
> +# endif
> +#endif
> --
> 2.25.1
>

LGTM.

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

Thanks.
diff mbox series

Patch

diff --git a/sysdeps/generic/ifunc-init.h b/sysdeps/generic/ifunc-init.h
index 7f69485de8..ee8a8289c8 100644
--- a/sysdeps/generic/ifunc-init.h
+++ b/sysdeps/generic/ifunc-init.h
@@ -50,5 +50,8 @@ 
    '__<symbol>_<variant>' as the optimized implementation and
    '<symbol>_ifunc_selector' as the IFUNC selector.  */
 #define REDIRECT_NAME	EVALUATOR1 (__redirect, SYMBOL_NAME)
-#define OPTIMIZE(name)	EVALUATOR2 (SYMBOL_NAME, name)
 #define IFUNC_SELECTOR	EVALUATOR1 (SYMBOL_NAME, ifunc_selector)
+#define OPTIMIZE1(name)	EVALUATOR1 (SYMBOL_NAME, name)
+#define OPTIMIZE2(name)	EVALUATOR2 (SYMBOL_NAME, name)
+/* Default is to use OPTIMIZE2.  */
+#define OPTIMIZE(name)	OPTIMIZE2(name)
diff --git a/sysdeps/x86_64/memcmp.S b/sysdeps/x86_64/memcmp.S
index 8a03e572e8..b53f2c0866 100644
--- a/sysdeps/x86_64/memcmp.S
+++ b/sysdeps/x86_64/memcmp.S
@@ -356,9 +356,10 @@  L(ATR32res):
 	.p2align 4,, 4
 END(memcmp)
 
-#undef bcmp
+#ifdef USE_AS_MEMCMPEQ
+libc_hidden_def (memcmp)
+#else
+# undef bcmp
 weak_alias (memcmp, bcmp)
-#undef __memcmpeq
-strong_alias (memcmp, __memcmpeq)
 libc_hidden_builtin_def (memcmp)
-libc_hidden_def (__memcmpeq)
+#endif
diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
index 26be40959c..044778585b 100644
--- a/sysdeps/x86_64/multiarch/Makefile
+++ b/sysdeps/x86_64/multiarch/Makefile
@@ -7,7 +7,9 @@  sysdep_routines += strncat-c stpncpy-c strncpy-c \
 		   memchr-sse2 rawmemchr-sse2 memchr-avx2 rawmemchr-avx2 \
 		   memrchr-sse2 memrchr-avx2 \
 		   memcmp-sse2 \
+		   memcmpeq-sse2 \
 		   memcmp-avx2-movbe \
+		   memcmpeq-avx2 \
 		   memcmp-sse4 memcpy-ssse3 \
 		   memmove-ssse3 \
 		   memcpy-ssse3-back \
@@ -42,6 +44,7 @@  sysdep_routines += strncat-c stpncpy-c strncpy-c \
 		   memset-avx512-unaligned-erms \
 		   memchr-avx2-rtm \
 		   memcmp-avx2-movbe-rtm \
+		   memcmpeq-avx2-rtm \
 		   memmove-avx-unaligned-erms-rtm \
 		   memrchr-avx2-rtm \
 		   memset-avx2-unaligned-erms-rtm \
@@ -61,6 +64,7 @@  sysdep_routines += strncat-c stpncpy-c strncpy-c \
 		   strrchr-avx2-rtm \
 		   memchr-evex \
 		   memcmp-evex-movbe \
+		   memcmpeq-evex \
 		   memmove-evex-unaligned-erms \
 		   memrchr-evex \
 		   memset-evex-unaligned-erms \
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index 39ab10613b..f7f3806d1d 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -38,6 +38,27 @@  __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   size_t i = 0;
 
+  /* Support sysdeps/x86_64/multiarch/memcmpeq.c.  */
+  IFUNC_IMPL (i, name, __memcmpeq,
+	      IFUNC_IMPL_ADD (array, i, __memcmpeq,
+			      (CPU_FEATURE_USABLE (AVX2)
+                   && CPU_FEATURE_USABLE (MOVBE)
+			       && CPU_FEATURE_USABLE (BMI2)),
+			      __memcmpeq_avx2)
+	      IFUNC_IMPL_ADD (array, i, __memcmpeq,
+			      (CPU_FEATURE_USABLE (AVX2)
+			       && CPU_FEATURE_USABLE (BMI2)
+                   && CPU_FEATURE_USABLE (MOVBE)
+			       && CPU_FEATURE_USABLE (RTM)),
+			      __memcmpeq_avx2_rtm)
+	      IFUNC_IMPL_ADD (array, i, __memcmpeq,
+			      (CPU_FEATURE_USABLE (AVX512VL)
+			       && CPU_FEATURE_USABLE (AVX512BW)
+                   && CPU_FEATURE_USABLE (MOVBE)
+			       && CPU_FEATURE_USABLE (BMI2)),
+			      __memcmpeq_evex)
+	      IFUNC_IMPL_ADD (array, i, __memcmpeq, 1, __memcmpeq_sse2))
+
   /* Support sysdeps/x86_64/multiarch/memchr.c.  */
   IFUNC_IMPL (i, name, memchr,
 	      IFUNC_IMPL_ADD (array, i, memchr,
diff --git a/sysdeps/x86_64/multiarch/ifunc-memcmpeq.h b/sysdeps/x86_64/multiarch/ifunc-memcmpeq.h
new file mode 100644
index 0000000000..3319a9568a
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/ifunc-memcmpeq.h
@@ -0,0 +1,49 @@ 
+/* Common definition for __memcmpeq ifunc selections.
+   All versions must be listed in ifunc-impl-list.c.
+   Copyright (C) 2017-2021 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 <init-arch.h>
+
+extern __typeof (REDIRECT_NAME) OPTIMIZE1 (sse2) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx2) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE1 (avx2_rtm) attribute_hidden;
+extern __typeof (REDIRECT_NAME) OPTIMIZE1 (evex) attribute_hidden;
+
+static inline void *
+IFUNC_SELECTOR (void)
+{
+  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_FEATURE_USABLE_P (cpu_features, MOVBE)
+      && 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))
+	return OPTIMIZE1 (evex);
+
+      if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
+	return OPTIMIZE1 (avx2_rtm);
+
+      if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
+	return OPTIMIZE1 (avx2);
+    }
+
+  return OPTIMIZE1 (sse2);
+}
diff --git a/sysdeps/x86_64/multiarch/memcmp-sse2.S b/sysdeps/x86_64/multiarch/memcmp-sse2.S
index 7b30b7ca2e..132d6fb339 100644
--- a/sysdeps/x86_64/multiarch/memcmp-sse2.S
+++ b/sysdeps/x86_64/multiarch/memcmp-sse2.S
@@ -17,7 +17,9 @@ 
    <https://www.gnu.org/licenses/>.  */
 
 #if IS_IN (libc)
-# define memcmp __memcmp_sse2
+# ifndef memcmp
+#  define memcmp __memcmp_sse2
+# endif
 
 # ifdef SHARED
 #  undef libc_hidden_builtin_def
diff --git a/sysdeps/x86_64/multiarch/memcmp.c b/sysdeps/x86_64/multiarch/memcmp.c
index 7b3409b1dd..fe725f3563 100644
--- a/sysdeps/x86_64/multiarch/memcmp.c
+++ b/sysdeps/x86_64/multiarch/memcmp.c
@@ -29,9 +29,6 @@ 
 libc_ifunc_redirected (__redirect_memcmp, memcmp, IFUNC_SELECTOR ());
 # undef bcmp
 weak_alias (memcmp, bcmp)
-# undef __memcmpeq
-strong_alias (memcmp, __memcmpeq)
-libc_hidden_def (__memcmpeq)
 
 # ifdef SHARED
 __hidden_ver1 (memcmp, __GI_memcmp, __redirect_memcmp)
diff --git a/sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S b/sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S
new file mode 100644
index 0000000000..24b6a0c9ff
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memcmpeq-avx2-rtm.S
@@ -0,0 +1,12 @@ 
+#ifndef MEMCMP
+# define MEMCMP __memcmpeq_avx2_rtm
+#endif
+
+#define ZERO_UPPER_VEC_REGISTERS_RETURN \
+  ZERO_UPPER_VEC_REGISTERS_RETURN_XTEST
+
+#define VZEROUPPER_RETURN jmp	 L(return_vzeroupper)
+
+#define SECTION(p) p##.avx.rtm
+
+#include "memcmpeq-avx2.S"
diff --git a/sysdeps/x86_64/multiarch/memcmpeq-avx2.S b/sysdeps/x86_64/multiarch/memcmpeq-avx2.S
new file mode 100644
index 0000000000..0181ea0d8d
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memcmpeq-avx2.S
@@ -0,0 +1,23 @@ 
+/* __memcmpeq optimized with AVX2.
+   Copyright (C) 2017-2021 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/>.  */
+
+#ifndef MEMCMP
+# define MEMCMP	__memcmpeq_avx2
+#endif
+
+#include "memcmp-avx2-movbe.S"
diff --git a/sysdeps/x86_64/multiarch/memcmpeq-evex.S b/sysdeps/x86_64/multiarch/memcmpeq-evex.S
new file mode 100644
index 0000000000..951e1e9560
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memcmpeq-evex.S
@@ -0,0 +1,23 @@ 
+/* __memcmpeq optimized with EVEX.
+   Copyright (C) 2017-2021 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/>.  */
+
+#ifndef MEMCMP
+# define MEMCMP	__memcmpeq_evex
+#endif
+
+#include "memcmp-evex-movbe.S"
diff --git a/sysdeps/x86_64/multiarch/memcmpeq-sse2.S b/sysdeps/x86_64/multiarch/memcmpeq-sse2.S
new file mode 100644
index 0000000000..c488cbbcd9
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memcmpeq-sse2.S
@@ -0,0 +1,23 @@ 
+/* __memcmpeq optimized with SSE2.
+   Copyright (C) 2017-2021 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/>.  */
+
+#ifndef memcmp
+# define memcmp	__memcmpeq_sse2
+#endif
+#define USE_AS_MEMCMPEQ	1
+#include "memcmp-sse2.S"
diff --git a/sysdeps/x86_64/multiarch/memcmpeq.c b/sysdeps/x86_64/multiarch/memcmpeq.c
new file mode 100644
index 0000000000..163e56047e
--- /dev/null
+++ b/sysdeps/x86_64/multiarch/memcmpeq.c
@@ -0,0 +1,35 @@ 
+/* Multiple versions of __memcmpeq.
+   All versions must be listed in ifunc-impl-list.c.
+   Copyright (C) 2017-2021 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 multiple versions only for the definition in libc.  */
+#if IS_IN (libc)
+# define __memcmpeq __redirect___memcmpeq
+# include <string.h>
+# undef __memcmpeq
+
+# define SYMBOL_NAME __memcmpeq
+# include "ifunc-memcmpeq.h"
+
+libc_ifunc_redirected (__redirect___memcmpeq, __memcmpeq, IFUNC_SELECTOR ());
+
+# ifdef SHARED
+__hidden_ver1 (__memcmpeq, __GI___memcmpeq, __redirect___memcmpeq)
+    __attribute__ ((visibility ("hidden"))) __attribute_copy__ (__memcmpeq);
+# endif
+#endif