[PATCH] D68457: [X86] Enable AVX512BW and AVX512VL for memcmp

[Craig Topper via Phabricator via llvm-commits]

craig.topper added a comment.

I'm fine with the 512-bit change to use byte compare with AVX512BW.

For 128/256, I wonder about the PTEST suggestion in the FIXME above this code. Unfortunately PTEST has 3 cycle latency on recent Intel CPUs. But it would avoid the GPR use entirely.


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https://reviews.llvm.org/D68457