From: Sunil Pandey <skpgkp2@gmail.com>
To: Noah Goldstein <goldstein.w.n@gmail.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>,
libc-alpha@sourceware.org, "H . J . Lu" <hjl.tools@gmail.com>
Subject: Re: [PATCH v2 2/6] x86-64: Require BMI2 for AVX2 str*cmp and wcs(n)cmp implementations
Date: Mon, 3 Oct 2022 09:19:46 -0700 [thread overview]
Message-ID: <CAMAf5_f4mvoyyvn36sEB8GTw+P6fV1PUzDdak8Z4qKsxRS7r6w@mail.gmail.com> (raw)
In-Reply-To: <CAFUsyfL5hCLMDyhE8YWRuH1TzZeMf9wczctSwo-Q=tTcp=dH6Q@mail.gmail.com>
Please separate this patch into 4 separate patches.
Patch1: sysdeps/x86_64/multiarch/strncmp.c
Patch2: sysdeps/x86_64/multiarch/strcmp.c
Patch3: sysdeps/x86_64/multiarch/ifunc-strcasecmp.h
Patch4: sysdeps/x86_64/multiarch/ifunc-impl-list.c
Rest of them looks OK to me.
On Sun, Oct 2, 2022 at 2:08 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> On Sun, Oct 2, 2022 at 8:34 AM Aurelien Jarno <aurelien@aurel32.net> wrote:
> >
> > The AVX2 str*cmp and wcs(n)cmp implementations use the 'bzhi'
> > instruction, which belongs to the BMI2 CPU feature.
> >
> > NB: It also uses the 'tzcnt' BMI1 instruction, but it is executed as BSF
> > as BSF if the CPU doesn't support TZCNT, and produces the same result
> > for non-zero input.
> >
> > Fixes: b77b06e0e296 ("x86: Optimize strcmp-avx2.S")
> > Partially resolves: BZ #29611
> > ---
> > sysdeps/x86_64/multiarch/ifunc-impl-list.c | 47 +++++++++++++++------
> > sysdeps/x86_64/multiarch/ifunc-strcasecmp.h | 1 +
> > sysdeps/x86_64/multiarch/strcmp.c | 4 +-
> > sysdeps/x86_64/multiarch/strncmp.c | 4 +-
> > 4 files changed, 39 insertions(+), 17 deletions(-)
> >
> > diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > index a71444eccb..fec8790c11 100644
> > --- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > +++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
> > @@ -448,13 +448,16 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > IFUNC_IMPL (i, name, strcasecmp,
> > X86_IFUNC_IMPL_ADD_V4 (array, i, strcasecmp,
> > (CPU_FEATURE_USABLE (AVX512VL)
> > - && CPU_FEATURE_USABLE (AVX512BW)),
> > + && CPU_FEATURE_USABLE (AVX512BW)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strcasecmp_evex)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strcasecmp,
> > - CPU_FEATURE_USABLE (AVX2),
> > + (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strcasecmp_avx2)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strcasecmp,
> > (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)
> > && CPU_FEATURE_USABLE (RTM)),
> > __strcasecmp_avx2_rtm)
> > X86_IFUNC_IMPL_ADD_V2 (array, i, strcasecmp,
> > @@ -470,13 +473,16 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > IFUNC_IMPL (i, name, strcasecmp_l,
> > X86_IFUNC_IMPL_ADD_V4 (array, i, strcasecmp,
> > (CPU_FEATURE_USABLE (AVX512VL)
> > - && CPU_FEATURE_USABLE (AVX512BW)),
> > + && CPU_FEATURE_USABLE (AVX512BW)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strcasecmp_l_evex)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strcasecmp,
> > - CPU_FEATURE_USABLE (AVX2),
> > + (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strcasecmp_l_avx2)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strcasecmp,
> > (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)
> > && CPU_FEATURE_USABLE (RTM)),
> > __strcasecmp_l_avx2_rtm)
> > X86_IFUNC_IMPL_ADD_V2 (array, i, strcasecmp_l,
> > @@ -585,10 +591,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > && CPU_FEATURE_USABLE (BMI2)),
> > __strcmp_evex)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strcmp,
> > - CPU_FEATURE_USABLE (AVX2),
> > + (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strcmp_avx2)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strcmp,
> > (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)
> > && CPU_FEATURE_USABLE (RTM)),
> > __strcmp_avx2_rtm)
> > X86_IFUNC_IMPL_ADD_V2 (array, i, strcmp,
> > @@ -638,13 +646,16 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > IFUNC_IMPL (i, name, strncasecmp,
> > X86_IFUNC_IMPL_ADD_V4 (array, i, strncasecmp,
> > (CPU_FEATURE_USABLE (AVX512VL)
> > - && CPU_FEATURE_USABLE (AVX512BW)),
> > + && CPU_FEATURE_USABLE (AVX512BW)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strncasecmp_evex)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strncasecmp,
> > - CPU_FEATURE_USABLE (AVX2),
> > + (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strncasecmp_avx2)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strncasecmp,
> > (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)
> > && CPU_FEATURE_USABLE (RTM)),
> > __strncasecmp_avx2_rtm)
> > X86_IFUNC_IMPL_ADD_V2 (array, i, strncasecmp,
> > @@ -660,13 +671,16 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > IFUNC_IMPL (i, name, strncasecmp_l,
> > X86_IFUNC_IMPL_ADD_V4 (array, i, strncasecmp,
> > (CPU_FEATURE_USABLE (AVX512VL)
> > - && CPU_FEATURE_USABLE (AVX512BW)),
> > + & CPU_FEATURE_USABLE (AVX512BW)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strncasecmp_l_evex)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strncasecmp,
> > - CPU_FEATURE_USABLE (AVX2),
> > + (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strncasecmp_l_avx2)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strncasecmp,
> > (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)
> > && CPU_FEATURE_USABLE (RTM)),
> > __strncasecmp_l_avx2_rtm)
> > X86_IFUNC_IMPL_ADD_V2 (array, i, strncasecmp_l,
> > @@ -796,10 +810,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > && CPU_FEATURE_USABLE (BMI2)),
> > __wcscmp_evex)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, wcscmp,
> > - CPU_FEATURE_USABLE (AVX2),
> > + (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __wcscmp_avx2)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, wcscmp,
> > (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)
> > && CPU_FEATURE_USABLE (RTM)),
> > __wcscmp_avx2_rtm)
> > /* ISA V2 wrapper for SSE2 implementation because the SSE2
> > @@ -816,10 +832,12 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > && CPU_FEATURE_USABLE (BMI2)),
> > __wcsncmp_evex)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, wcsncmp,
> > - CPU_FEATURE_USABLE (AVX2),
> > + (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __wcsncmp_avx2)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, wcsncmp,
> > (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)
> > && CPU_FEATURE_USABLE (RTM)),
> > __wcsncmp_avx2_rtm)
> > /* ISA V2 wrapper for GENERIC implementation because the
> > @@ -1162,13 +1180,16 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
> > IFUNC_IMPL (i, name, strncmp,
> > X86_IFUNC_IMPL_ADD_V4 (array, i, strncmp,
> > (CPU_FEATURE_USABLE (AVX512VL)
> > - && CPU_FEATURE_USABLE (AVX512BW)),
> > + && CPU_FEATURE_USABLE (AVX512BW)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strncmp_evex)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strncmp,
> > - CPU_FEATURE_USABLE (AVX2),
> > + (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)),
> > __strncmp_avx2)
> > X86_IFUNC_IMPL_ADD_V3 (array, i, strncmp,
> > (CPU_FEATURE_USABLE (AVX2)
> > + && CPU_FEATURE_USABLE (BMI2)
> > && CPU_FEATURE_USABLE (RTM)),
> > __strncmp_avx2_rtm)
> > X86_IFUNC_IMPL_ADD_V2 (array, i, strncmp,
> > diff --git a/sysdeps/x86_64/multiarch/ifunc-strcasecmp.h b/sysdeps/x86_64/multiarch/ifunc-strcasecmp.h
> > index 68646ef199..7622af259c 100644
> > --- a/sysdeps/x86_64/multiarch/ifunc-strcasecmp.h
> > +++ b/sysdeps/x86_64/multiarch/ifunc-strcasecmp.h
> > @@ -34,6 +34,7 @@ IFUNC_SELECTOR (void)
> > const struct cpu_features *cpu_features = __get_cpu_features ();
> >
> > 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, ))
> > {
> > diff --git a/sysdeps/x86_64/multiarch/strcmp.c b/sysdeps/x86_64/multiarch/strcmp.c
> > index fdd5afe3af..9d6c9f66ba 100644
> > --- a/sysdeps/x86_64/multiarch/strcmp.c
> > +++ b/sysdeps/x86_64/multiarch/strcmp.c
> > @@ -45,12 +45,12 @@ IFUNC_SELECTOR (void)
> > const struct cpu_features *cpu_features = __get_cpu_features ();
> >
> > 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 (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
> > - && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)
> > - && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, BMI2))
> > + && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
> > return OPTIMIZE (evex);
> >
> > if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
> > diff --git a/sysdeps/x86_64/multiarch/strncmp.c b/sysdeps/x86_64/multiarch/strncmp.c
> > index 4ebe4bde30..c4f8b6bbb5 100644
> > --- a/sysdeps/x86_64/multiarch/strncmp.c
> > +++ b/sysdeps/x86_64/multiarch/strncmp.c
> > @@ -41,12 +41,12 @@ IFUNC_SELECTOR (void)
> > const struct cpu_features *cpu_features = __get_cpu_features ();
> >
> > 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 (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
> > - && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512BW)
> > - && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, BMI2))
> > + && X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX512BW))
> > return OPTIMIZE (evex);
> >
> > if (CPU_FEATURE_USABLE_P (cpu_features, RTM))
> > --
> > 2.35.1
> >
>
> LGTM.
next prev parent reply other threads:[~2022-10-03 16:20 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-02 12:34 [PATCH v2 0/6] x86: Fix AVX2 string functions requiring BMI1, BMI2 or LZCNT (BZ #29611) Aurelien Jarno
2022-10-02 12:34 ` [PATCH v2 1/6] x86: include BMI1 and BMI2 in x86-64-v3 level Aurelien Jarno
2022-10-02 21:07 ` Noah Goldstein
2022-10-02 12:34 ` [PATCH v2 2/6] x86-64: Require BMI2 for AVX2 str*cmp and wcs(n)cmp implementations Aurelien Jarno
2022-10-02 21:08 ` Noah Goldstein
2022-10-03 16:19 ` Sunil Pandey [this message]
2022-10-03 17:35 ` Aurelien Jarno
2022-10-03 17:50 ` Noah Goldstein
2022-10-03 18:43 ` Sunil Pandey
2022-10-03 19:21 ` Aurelien Jarno
2022-10-03 19:59 ` Aurelien Jarno
2022-10-03 20:51 ` Sunil Pandey
2022-10-02 12:34 ` [PATCH v2 3/6] x86-64: Require BMI2 for AVX2 (raw|w)memchr implementations Aurelien Jarno
2022-10-02 21:08 ` Noah Goldstein
2022-10-02 12:34 ` [PATCH v2 4/6] x86-64: Require LZCNT for AVX2 memrchr implementation Aurelien Jarno
2022-10-02 21:08 ` Noah Goldstein
2022-10-02 12:34 ` [PATCH v2 5/6] x86-64: Require BMI1/BMI2 for AVX2 strrchr and wcsrchr implementations Aurelien Jarno
2022-10-02 21:08 ` Noah Goldstein
2022-10-02 12:34 ` [PATCH v2 6/6] x86-64: Require BMI2 for AVX2 memrchr implementation Aurelien Jarno
2022-10-02 21:09 ` Noah Goldstein
2022-10-02 16:21 ` [PATCH v2 0/6] x86: Fix AVX2 string functions requiring BMI1, BMI2 or LZCNT (BZ #29611) Noah Goldstein
2022-10-02 18:09 ` Aurelien Jarno
2022-10-02 21:11 ` Noah Goldstein
2022-10-03 17:36 ` Aurelien Jarno
2022-10-03 17:51 ` Noah Goldstein
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