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 2.33 7/8] x86-64: Require BMI2 and LZCNT for AVX2 memrchr implementation
Date: Tue, 4 Oct 2022 00:04:47 +0200 [thread overview]
Message-ID: <20221003220448.3298308-7-aurelien@aurel32.net> (raw)
In-Reply-To: <20221003220448.3298308-1-aurelien@aurel32.net>
The AVX2 memrchr implementation uses the 'shlxl' instruction, which
belongs to the BMI2 CPU feature and uses the 'lzcnt' instruction, which
belongs to the LZCNT CPU feature.
Fixes: af5306a735eb ("x86: Optimize memrchr-avx2.S")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
(cherry picked from commit 3c0c78afabfed4b6fc161c159e628fbf14ff370b)
---
sysdeps/x86_64/multiarch/ifunc-avx2.h | 1 +
sysdeps/x86_64/multiarch/ifunc-impl-list.c | 10 ++++++++--
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/sysdeps/x86_64/multiarch/ifunc-avx2.h b/sysdeps/x86_64/multiarch/ifunc-avx2.h
index 6de72f7272..52bd00ea5c 100644
--- a/sysdeps/x86_64/multiarch/ifunc-avx2.h
+++ b/sysdeps/x86_64/multiarch/ifunc-avx2.h
@@ -31,6 +31,7 @@ IFUNC_SELECTOR (void)
if (CPU_FEATURE_USABLE_P (cpu_features, AVX2)
&& CPU_FEATURE_USABLE_P (cpu_features, BMI2)
+ && CPU_FEATURE_USABLE_P (cpu_features, LZCNT)
&& CPU_FEATURES_ARCH_P (cpu_features, AVX_Fast_Unaligned_Load))
{
if (CPU_FEATURE_USABLE_P (cpu_features, AVX512VL)
diff --git a/sysdeps/x86_64/multiarch/ifunc-impl-list.c b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
index 81640cf006..d1fc1e75d6 100644
--- a/sysdeps/x86_64/multiarch/ifunc-impl-list.c
+++ b/sysdeps/x86_64/multiarch/ifunc-impl-list.c
@@ -174,15 +174,21 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
/* Support sysdeps/x86_64/multiarch/memrchr.c. */
IFUNC_IMPL (i, name, memrchr,
IFUNC_IMPL_ADD (array, i, memrchr,
- CPU_FEATURE_USABLE (AVX2),
+ (CPU_FEATURE_USABLE (AVX2)
+ && CPU_FEATURE_USABLE (BMI2)
+ && CPU_FEATURE_USABLE (LZCNT)),
__memrchr_avx2)
IFUNC_IMPL_ADD (array, i, memrchr,
(CPU_FEATURE_USABLE (AVX2)
+ && CPU_FEATURE_USABLE (BMI2)
+ && CPU_FEATURE_USABLE (LZCNT)
&& CPU_FEATURE_USABLE (RTM)),
__memrchr_avx2_rtm)
IFUNC_IMPL_ADD (array, i, memrchr,
(CPU_FEATURE_USABLE (AVX512VL)
- && CPU_FEATURE_USABLE (AVX512BW)),
+ && CPU_FEATURE_USABLE (AVX512BW)
+ && CPU_FEATURE_USABLE (BMI2)
+ && CPU_FEATURE_USABLE (LZCNT)),
__memrchr_evex)
IFUNC_IMPL_ADD (array, i, memrchr, 1, __memrchr_sse2))
--
2.35.1
next prev parent reply other threads:[~2022-10-03 22:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-03 22:04 [COMMITTED 2.33 1/8] x86: include BMI1 and BMI2 in x86-64-v3 level Aurelien Jarno
2022-10-03 22:04 ` [COMMITTED 2.33 2/8] x86-64: Require BMI2 for AVX2 str(n)casecmp implementations Aurelien Jarno
2022-10-03 22:04 ` [COMMITTED 2.33 3/8] x86-64: Require BMI2 for AVX2 strcmp implementation Aurelien Jarno
2022-10-03 22:04 ` [COMMITTED 2.33 4/8] x86-64: Require BMI2 for AVX2 strncmp implementation Aurelien Jarno
2022-10-03 22:04 ` [COMMITTED 2.33 5/8] x86-64: Require BMI2 for AVX2 wcs(n)cmp implementations Aurelien Jarno
2022-10-03 22:04 ` [COMMITTED 2.33 6/8] x86-64: Require BMI2 for AVX2 (raw|w)memchr implementations Aurelien Jarno
2022-10-03 22:04 ` Aurelien Jarno [this message]
2022-10-03 22:04 ` [COMMITTED 2.33 8/8] x86-64: Require BMI1/BMI2 for AVX2 strrchr and wcsrchr implementations Aurelien Jarno
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