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| author | H.J. Lu <hjl.tools@gmail.com> | 2021-10-29 12:56:53 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2021-11-01 07:53:04 -0700 |
| commit | 14dbbf46a007ae5df36646b51ad0c9e5f5259f30 (patch) | |
| tree | 7e0470499bd6cea64b76b1f0392bf23aeea2a19e /sysdeps/x86/cpu-tunables.c | |
| parent | c46e9afb2df5fc9e39ff4d13777e4b4c26e04e55 (diff) | |
| download | glibc-14dbbf46a007ae5df36646b51ad0c9e5f5259f30.zip glibc-14dbbf46a007ae5df36646b51ad0c9e5f5259f30.tar.gz glibc-14dbbf46a007ae5df36646b51ad0c9e5f5259f30.tar.bz2 | |
x86-64: Remove Prefer_AVX2_STRCMP
Remove Prefer_AVX2_STRCMP to enable EVEX strcmp. When comparing 2 32-byte
strings, EVEX strcmp has been improved to require 1 load, 1 VPTESTM, 1
VPCMP, 1 KMOVD and 1 INCL instead of 2 loads, 3 VPCMPs, 2 KORDs, 1 KMOVD
and 1 TESTL while AVX2 strcmp requires 1 load, 2 VPCMPEQs, 1 VPMINU, 1
VPMOVMSKB and 1 TESTL. EVEX strcmp is now faster than AVX2 strcmp by up
to 40% on Tiger Lake and Ice Lake.
Diffstat (limited to 'sysdeps/x86/cpu-tunables.c')
| -rw-r--r-- | sysdeps/x86/cpu-tunables.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c index 00fe504..61b05e5 100644 --- a/sysdeps/x86/cpu-tunables.c +++ b/sysdeps/x86/cpu-tunables.c @@ -239,8 +239,6 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp) CHECK_GLIBC_IFUNC_PREFERRED_BOTH (n, cpu_features, Fast_Copy_Backward, disable, 18); - CHECK_GLIBC_IFUNC_PREFERRED_NEED_BOTH - (n, cpu_features, Prefer_AVX2_STRCMP, AVX2, disable, 18); } break; case 19: |