lib/glibc
1
0
Fork 0
mirror of https://sourceware.org/git/glibc.git synced 2025-08-08 17:42:12 +03:00
Code Activity

x86-64: Remove Prefer_AVX2_STRCMP

Browse Source 
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.
This commit is contained in:
H.J. Lu
2021-10-29 12:56:53 -07:00
parent c46e9afb2d
commit 14dbbf46a0
5 changed files with 2 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
sysdeps/x86/include/cpu-features-preferred_feature_index_1.def
View File

@@ -32,5 +32,4 @@ BIT (Prefer_ERMS)
BIT (Prefer_No_AVX512)
BIT (MathVec_Prefer_No_AVX512)
BIT (Prefer_FSRM)
BIT (Prefer_AVX2_STRCMP)
BIT (Avoid_Short_Distance_REP_MOVSB)