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authorH.J. Lu <hjl.tools@gmail.com>2021-10-29 12:56:53 -0700
committerH.J. Lu <hjl.tools@gmail.com>2021-11-01 07:53:04 -0700
commit14dbbf46a007ae5df36646b51ad0c9e5f5259f30 (patch)
tree7e0470499bd6cea64b76b1f0392bf23aeea2a19e /Rules
parentc46e9afb2df5fc9e39ff4d13777e4b4c26e04e55 (diff)
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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 'Rules')
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