| commit | f31a5a884ed84bd37032729d4d1eb9d06c9f3c29 | |
| author | Aurelien Jarno <aurelien@aurel32.net> | |
| Mon, 3 Oct 2022 21:46:11 +0000 (3 23:46 +0200) | ||
| committer | Aurelien Jarno <aurelien@aurel32.net> | |
| Mon, 3 Oct 2022 21:46:11 +0000 (3 23:46 +0200) | ||
| tree | efde63e1cf974d18a9c0ae0a54e446c162866fe0 | treesnapshot (tar.gz zip) |
| parent | fc7de1d9b99ae1676bc626ddca422d7abee0eb48 | commitdiff |
x86-64: Require BMI2 for AVX2 wcs(n)cmp implementations
The AVX2 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.
Partially fixes: b77b06e0e296 ("x86: Optimize strcmp-avx2.S")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
The AVX2 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.
Partially fixes: b77b06e0e296 ("x86: Optimize strcmp-avx2.S")
Partially resolves: BZ #29611
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
| sysdeps/x86_64/multiarch/ifunc-impl-list.c | diffblobblamehistory |