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| author | Aurelien Jarno <aurelien@aurel32.net> | 2022-10-03 23:16:46 +0200 |
|---|---|---|
| committer | Aurelien Jarno <aurelien@aurel32.net> | 2022-10-04 00:00:59 +0200 |
| commit | 36d6b9be3d7008a78e1f6e2e2db1947b76b206d8 (patch) | |
| tree | ab5cb55f1e570b85b56696ada4dc220339759209 | |
| parent | 94b9c1b6409e34f3f0b2339f77d7ee78087422eb (diff) | |
| download | glibc-36d6b9be3d7008a78e1f6e2e2db1947b76b206d8.tar.gz glibc-36d6b9be3d7008a78e1f6e2e2db1947b76b206d8.tar.xz glibc-36d6b9be3d7008a78e1f6e2e2db1947b76b206d8.zip | |
x86-64: Require BMI2 and LZCNT for AVX2 memrchr implementation
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)
| -rw-r--r-- | sysdeps/x86_64/multiarch/ifunc-avx2.h | 1 | ||||
| -rw-r--r-- | 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)) |