[PATCH] D91726: [LoopIdiom] 'left-shift until bittest' idiom: support canonical sign bit mask

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


================
Comment at: llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp:2081
+
+  if (!MatchVariableBitMask() && !MatchConstantBitMask() &&
+      !MatchDecomposableConstantBitMask()) {
----------------
At least for MatchVariableBitMask and MatchConstantBitMask isn't this doing duplicate work finding the ICmp and looking through the phi? And only then checking the differing part of the pattern?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D91726/new/

https://reviews.llvm.org/D91726