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| author | Aurelien Jarno <aurelien@aurel32.net> | 2022-10-03 23:46:11 +0200 |
|---|---|---|
| committer | Aurelien Jarno <aurelien@aurel32.net> | 2022-10-03 23:46:11 +0200 |
| commit | 10f79d3670b036925da63dc532b122d27ce65ff8 (patch) | |
| tree | d75602ba126717f5ba747f1a6e9d4ed31338d891 /sysdeps/x86_64/multiarch/ifunc-strcasecmp.h | |
| parent | b80f16adbd979831bf25ea491e1261e81885c2b6 (diff) | |
| download | glibc-10f79d3670b036925da63dc532b122d27ce65ff8.tar.gz glibc-10f79d3670b036925da63dc532b122d27ce65ff8.tar.xz glibc-10f79d3670b036925da63dc532b122d27ce65ff8.zip | |
x86-64: Require BMI2 for AVX2 str(n)casecmp implementations
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>
Diffstat (limited to 'sysdeps/x86_64/multiarch/ifunc-strcasecmp.h')
| -rw-r--r-- | sysdeps/x86_64/multiarch/ifunc-strcasecmp.h | 1 |
1 files changed, 1 insertions, 0 deletions
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, )) { |