From: Aurelien Jarno <aurelien@aurel32.net>
To: libc-stable@sourceware.org
Cc: Aurelien Jarno <aurelien@aurel32.net>,
Noah Goldstein <goldstein.w.n@gmail.com>
Subject: [COMMITTED 2.35 2/8] x86-64: Require BMI2 for AVX2 str(n)casecmp implementations
Date: Mon, 3 Oct 2022 23:56:08 +0200 [thread overview]
Message-ID: <20221003215614.3294221-2-aurelien@aurel32.net> (raw)
In-Reply-To: <20221003215614.3294221-1-aurelien@aurel32.net>
The AVX2 str(n)casecmp 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.
Partially fixes: b77b06e0e296 ("x86: Optimize strcmp-avx2.S")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
(cherry picked from commit 10f79d3670b036925da63dc532b122d27ce65ff8)
---
sysdeps/x86_64/multiarch/ifunc-impl-list.c | 28 +++++++++++++++------
sysdeps/x86_64/multiarch/ifunc-strcasecmp.h | 1 +
2 files changed, 21 insertions(+), 8 deletions(-)
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index e97218f624..2d8c87a42e 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -404,13 +404,16 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
IFUNC_IMPL (i, name, strcasecmp,
IFUNC_IMPL_ADD (array, i, strcasecmp,
(CPU_FEATURE_USABLE (AVX512VL)
- && CPU_FEATURE_USABLE (AVX512BW)),
+ && CPU_FEATURE_USABLE (AVX512BW)
+ && CPU_FEATURE_USABLE (BMI2)),
__strcasecmp_evex)
IFUNC_IMPL_ADD (array, i, strcasecmp,
- CPU_FEATURE_USABLE (AVX2),
+ (CPU_FEATURE_USABLE (AVX2)
+ && CPU_FEATURE_USABLE (BMI2)),
__strcasecmp_avx2)
IFUNC_IMPL_ADD (array, i, strcasecmp,
(CPU_FEATURE_USABLE (AVX2)
+ && CPU_FEATURE_USABLE (BMI2)
&& CPU_FEATURE_USABLE (RTM)),
__strcasecmp_avx2_rtm)
IFUNC_IMPL_ADD (array, i, strcasecmp,
@@ -425,13 +428,16 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
IFUNC_IMPL (i, name, strcasecmp_l,
IFUNC_IMPL_ADD (array, i, strcasecmp,
(CPU_FEATURE_USABLE (AVX512VL)
- && CPU_FEATURE_USABLE (AVX512BW)),
+ && CPU_FEATURE_USABLE (AVX512BW)
+ && CPU_FEATURE_USABLE (BMI2)),
__strcasecmp_l_evex)
IFUNC_IMPL_ADD (array, i, strcasecmp,
- CPU_FEATURE_USABLE (AVX2),
+ (CPU_FEATURE_USABLE (AVX2)
+ && CPU_FEATURE_USABLE (BMI2)),
__strcasecmp_l_avx2)
IFUNC_IMPL_ADD (array, i, strcasecmp,
(CPU_FEATURE_USABLE (AVX2)
+ && CPU_FEATURE_USABLE (BMI2)
&& CPU_FEATURE_USABLE (RTM)),
__strcasecmp_l_avx2_rtm)
IFUNC_IMPL_ADD (array, i, strcasecmp_l,
@@ -560,13 +566,16 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
IFUNC_IMPL (i, name, strncasecmp,
IFUNC_IMPL_ADD (array, i, strncasecmp,
(CPU_FEATURE_USABLE (AVX512VL)
- && CPU_FEATURE_USABLE (AVX512BW)),
+ && CPU_FEATURE_USABLE (AVX512BW)
+ && CPU_FEATURE_USABLE (BMI2)),
__strncasecmp_evex)
IFUNC_IMPL_ADD (array, i, strncasecmp,
- CPU_FEATURE_USABLE (AVX2),
+ (CPU_FEATURE_USABLE (AVX2)
+ && CPU_FEATURE_USABLE (BMI2)),
__strncasecmp_avx2)
IFUNC_IMPL_ADD (array, i, strncasecmp,
(CPU_FEATURE_USABLE (AVX2)
+ && CPU_FEATURE_USABLE (BMI2)
&& CPU_FEATURE_USABLE (RTM)),
__strncasecmp_avx2_rtm)
IFUNC_IMPL_ADD (array, i, strncasecmp,
@@ -582,13 +591,16 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
IFUNC_IMPL (i, name, strncasecmp_l,
IFUNC_IMPL_ADD (array, i, strncasecmp,
(CPU_FEATURE_USABLE (AVX512VL)
- && CPU_FEATURE_USABLE (AVX512BW)),
+ & CPU_FEATURE_USABLE (AVX512BW)
+ && CPU_FEATURE_USABLE (BMI2)),
__strncasecmp_l_evex)
IFUNC_IMPL_ADD (array, i, strncasecmp,
- CPU_FEATURE_USABLE (AVX2),
+ (CPU_FEATURE_USABLE (AVX2)
+ && CPU_FEATURE_USABLE (BMI2)),
__strncasecmp_l_avx2)
IFUNC_IMPL_ADD (array, i, strncasecmp,
(CPU_FEATURE_USABLE (AVX2)
+ && CPU_FEATURE_USABLE (BMI2)
&& CPU_FEATURE_USABLE (RTM)),
__strncasecmp_l_avx2_rtm)
IFUNC_IMPL_ADD (array, i, strncasecmp_l,
diff --git a/sysdeps/x86_64/multiarch/ifunc-strcasecmp.h b/sysdeps/x86_64/multiarch/ifunc-strcasecmp.h
index 766539c241..e201f6e4d8 100644
--- a/sysdeps/x86_64/multiarch/ifunc-strcasecmp.h
+++ b/sysdeps/x86_64/multiarch/ifunc-strcasecmp.h
@@ -32,6 +32,7 @@ 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)
--
2.35.1
next prev parent reply other threads:[~2022-10-03 21:56 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-03 21:56 [COMMITTED 2.35 1/8] x86: include BMI1 and BMI2 in x86-64-v3 level Aurelien Jarno
2022-10-03 21:56 ` Aurelien Jarno [this message]
2022-10-03 21:56 ` [COMMITTED 2.35 3/8] x86-64: Require BMI2 for AVX2 strcmp implementation Aurelien Jarno
2022-10-03 21:56 ` [COMMITTED 2.35 4/8] x86-64: Require BMI2 for AVX2 strncmp implementation Aurelien Jarno
2022-10-03 21:56 ` [COMMITTED 2.35 5/8] x86-64: Require BMI2 for AVX2 wcs(n)cmp implementations Aurelien Jarno
2022-10-03 21:56 ` [COMMITTED 2.35 6/8] x86-64: Require BMI2 for AVX2 (raw|w)memchr implementations Aurelien Jarno
2022-10-03 21:56 ` [COMMITTED 2.35 7/8] x86-64: Require BMI2 and LZCNT for AVX2 memrchr implementation Aurelien Jarno
2022-10-03 21:56 ` [COMMITTED 2.35 8/8] x86-64: Require BMI1/BMI2 for AVX2 strrchr and wcsrchr implementations Aurelien Jarno
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