[PATCH v1 1/4] x86-64: Add wcslen optimize for sse4.1

H.J. Lu hjl.tools@gmail.com
Wed Jun 23 17:29:46 GMT 2021


On Tue, Jun 22, 2021 at 11:30 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> No bug. This comment adds the ifunc / build infrastructure
> necessary for wcslen to prefer the sse4.1 implementation
> in strlen-vec.S. test-wcslen.c is passing.
>
> Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
> ---
> Rebased on [PATCH] x86-64: Move strlen.S to multiarch/strlen-vec.S
>  sysdeps/x86_64/multiarch/Makefile          |  4 +-
>  sysdeps/x86_64/multiarch/ifunc-impl-list.c |  3 ++
>  sysdeps/x86_64/multiarch/ifunc-wcslen.h    | 52 ++++++++++++++++++++++
>  sysdeps/x86_64/multiarch/wcslen-sse4_1.S   |  4 ++
>  sysdeps/x86_64/multiarch/wcslen.c          |  2 +-
>  sysdeps/x86_64/multiarch/wcsnlen.c         | 34 +-------------
>  6 files changed, 63 insertions(+), 36 deletions(-)
>  create mode 100644 sysdeps/x86_64/multiarch/ifunc-wcslen.h
>  create mode 100644 sysdeps/x86_64/multiarch/wcslen-sse4_1.S
>
> diff --git a/sysdeps/x86_64/multiarch/Makefile b/sysdeps/x86_64/multiarch/Makefile
> index 2c2aad3a7e..26be40959c 100644
> --- a/sysdeps/x86_64/multiarch/Makefile
> +++ b/sysdeps/x86_64/multiarch/Makefile
> @@ -95,8 +95,8 @@ sysdep_routines += wmemcmp-sse4 wmemcmp-ssse3 wmemcmp-c \
>                    wcscpy-ssse3 wcscpy-c \
>                    wcschr-sse2 wcschr-avx2 \
>                    wcsrchr-sse2 wcsrchr-avx2 \
> -                  wcsnlen-sse4_1 wcsnlen-c \
> -                  wcslen-sse2 wcslen-avx2 wcsnlen-avx2 \
> +                  wcslen-sse2 wcslen-sse4_1 wcslen-avx2 \
> +                  wcsnlen-c wcsnlen-sse4_1 wcsnlen-avx2 \
>                    wcschr-avx2-rtm \
>                    wcscmp-avx2-rtm \
>                    wcslen-avx2-rtm \
> diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> index 15eda47667..dbd1ebf298 100644
> --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> @@ -684,6 +684,9 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
>                                && CPU_FEATURE_USABLE (AVX512BW)
>                                && CPU_FEATURE_USABLE (BMI2)),
>                               __wcslen_evex)
> +             IFUNC_IMPL_ADD (array, i, wcsnlen,
> +                             CPU_FEATURE_USABLE (SSE4_1),
> +                             __wcsnlen_sse4_1)
>               IFUNC_IMPL_ADD (array, i, wcslen, 1, __wcslen_sse2))
>
>    /* Support sysdeps/x86_64/multiarch/wcsnlen.c.  */
> diff --git a/sysdeps/x86_64/multiarch/ifunc-wcslen.h b/sysdeps/x86_64/multiarch/ifunc-wcslen.h
> new file mode 100644
> index 0000000000..39e3347378
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/ifunc-wcslen.h
> @@ -0,0 +1,52 @@
> +/* Common definition for ifunc selections for wcslen and wcsnlen
> +   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) OPTIMIZE (sse2) attribute_hidden;
> +extern __typeof (REDIRECT_NAME) OPTIMIZE (sse4_1) 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;
> +
> +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_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 OPTIMIZE (evex);
> +
> +      if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
> +       return OPTIMIZE (avx2_rtm);
> +
> +      if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
> +       return OPTIMIZE (avx2);
> +    }
> +
> +  if (CPU_FEATURE_USABLE_P (cpu_features, SSE4_1))
> +    return OPTIMIZE (sse4_1);
> +
> +  return OPTIMIZE (sse2);
> +}
> diff --git a/sysdeps/x86_64/multiarch/wcslen-sse4_1.S b/sysdeps/x86_64/multiarch/wcslen-sse4_1.S
> new file mode 100644
> index 0000000000..7e62621afc
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/wcslen-sse4_1.S
> @@ -0,0 +1,4 @@
> +#define AS_WCSLEN
> +#define strlen __wcslen_sse4_1
> +
> +#include "strlen-vec.S"
> diff --git a/sysdeps/x86_64/multiarch/wcslen.c b/sysdeps/x86_64/multiarch/wcslen.c
> index f89bed42a0..3032061d3b 100644
> --- a/sysdeps/x86_64/multiarch/wcslen.c
> +++ b/sysdeps/x86_64/multiarch/wcslen.c
> @@ -24,7 +24,7 @@
>  # undef __wcslen
>
>  # define SYMBOL_NAME wcslen
> -# include "ifunc-avx2.h"
> +# include "ifunc-wcslen.h"
>
>  libc_ifunc_redirected (__redirect_wcslen, __wcslen, IFUNC_SELECTOR ());
>  weak_alias (__wcslen, wcslen);
> diff --git a/sysdeps/x86_64/multiarch/wcsnlen.c b/sysdeps/x86_64/multiarch/wcsnlen.c
> index 4983f1b222..2963fbe059 100644
> --- a/sysdeps/x86_64/multiarch/wcsnlen.c
> +++ b/sysdeps/x86_64/multiarch/wcsnlen.c
> @@ -24,39 +24,7 @@
>  # undef __wcsnlen
>
>  # define SYMBOL_NAME wcsnlen
> -# 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) attribute_hidden;
> -extern __typeof (REDIRECT_NAME) OPTIMIZE (avx2_rtm) attribute_hidden;
> -extern __typeof (REDIRECT_NAME) OPTIMIZE (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_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
> -    {
> -      if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
> -         && CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)
> -         && CPU_FEATURE_USABLE_P (cpu_features, BMI2))
> -       return OPTIMIZE (evex);
> -
> -      if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
> -       return OPTIMIZE (avx2_rtm);
> -
> -      if (!CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER))
> -       return OPTIMIZE (avx2);
> -    }
> -
> -  if (CPU_FEATURE_USABLE_P (cpu_features, SSE4_1))
> -    return OPTIMIZE (sse4_1);
> -
> -  return OPTIMIZE (sse2);
> -}
> +# include "ifunc-wcslen.h"
>
>  libc_ifunc_redirected (__redirect_wcsnlen, __wcsnlen, IFUNC_SELECTOR ());
>  weak_alias (__wcsnlen, wcsnlen);
> --
> 2.25.1
>

LGTM.

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

Thanks.

-- 
H.J.


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