[PATCH] D81327: [X86] Teach combineBitcastvxi1 to prefer movmsk on avx512 in more cases

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: RKSimon, spatel.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

If the input to the bitcast is a sign bit test, it makes sense to
directly use vpmovmskb or vmovmskps/pd. This removes the need to
copy the sign bits to a k-register and then to a GPR.

Fixes PR46200.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D81327

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/avx512bwvl-intrinsics-upgrade.ll
  llvm/test/CodeGen/X86/avx512dqvl-intrinsics-upgrade.ll
  llvm/test/CodeGen/X86/bitcast-setcc-256.ll
  llvm/test/CodeGen/X86/bitcast-vector-bool.ll
  llvm/test/CodeGen/X86/movmsk-cmp.ll

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