[PATCH] D118539: [InstCombine] try to fold one-demanded-bit-of-multiply

[Sanjay Patel via Phabricator via llvm-commits]

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This is a generalization of the icmp fold in D118061 <https://reviews.llvm.org/D118061> (and that can probably be abandoned if this is sufficient). 
We're looking for a disguised form of "odd * odd must be odd".
Some Alive2 proofs to show correctness:
https://alive2.llvm.org/ce/z/60Y8hz
https://alive2.llvm.org/ce/z/HfAP6R


https://reviews.llvm.org/D118539

Files:
  llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
  llvm/test/Transforms/InstCombine/icmp-mul-and.ll
  llvm/test/Transforms/InstCombine/mul-masked-bits.ll

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