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author | H.J. Lu <hjl.tools@gmail.com> | 2021-10-29 12:40:20 -0700 |
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committer | H.J. Lu <hjl.tools@gmail.com> | 2021-11-01 07:52:56 -0700 |
commit | c46e9afb2df5fc9e39ff4d13777e4b4c26e04e55 (patch) | |
tree | 92623deb486f7d21b4f912bd3faa04d5a7a4a9f7 /sysdeps/x86 | |
parent | 79d0fc65395716c1d95931064c7bf37852203c66 (diff) | |
download | glibc-c46e9afb2df5fc9e39ff4d13777e4b4c26e04e55.tar.gz glibc-c46e9afb2df5fc9e39ff4d13777e4b4c26e04e55.tar.xz glibc-c46e9afb2df5fc9e39ff4d13777e4b4c26e04e55.zip |
x86-64: Improve EVEX strcmp with masked load
In strcmp-evex.S, to compare 2 32-byte strings, replace VMOVU (%rdi, %rdx), %YMM0 VMOVU (%rsi, %rdx), %YMM1 /* Each bit in K0 represents a mismatch in YMM0 and YMM1. */ VPCMP $4, %YMM0, %YMM1, %k0 VPCMP $0, %YMMZERO, %YMM0, %k1 VPCMP $0, %YMMZERO, %YMM1, %k2 /* Each bit in K1 represents a NULL in YMM0 or YMM1. */ kord %k1, %k2, %k1 /* Each bit in K1 represents a NULL or a mismatch. */ kord %k0, %k1, %k1 kmovd %k1, %ecx testl %ecx, %ecx jne L(last_vector) with VMOVU (%rdi, %rdx), %YMM0 VPTESTM %YMM0, %YMM0, %k2 /* Each bit cleared in K1 represents a mismatch or a null CHAR in YMM0 and 32 bytes at (%rsi, %rdx). */ VPCMP $0, (%rsi, %rdx), %YMM0, %k1{%k2} kmovd %k1, %ecx incl %ecx jne L(last_vector) It makes EVEX strcmp faster than AVX2 strcmp by up to 40% on Tiger Lake and Ice Lake. Co-Authored-By: Noah Goldstein <goldstein.w.n@gmail.com>
Diffstat (limited to 'sysdeps/x86')
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