[all-commits] [llvm/llvm-project] aa4796: [InstCombine] canNarrowShiftAmt - replace custom C...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: aa47962cc9493cd79ca78954e721ed02479729c7
      https://github.com/llvm/llvm-project/commit/aa47962cc9493cd79ca78954e721ed02479729c7
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2020-10-08 (Thu, 08 Oct 2020)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

  Log Message:
  -----------
  [InstCombine] canNarrowShiftAmt - replace custom Constant matching with m_SpecificInt_ICMP

The existing code ignores undef values which matches m_SpecificInt_ICMP, although m_SpecificInt_ICMP returns false for an all-undef constant, I've added test coverage at rGfe0197e194a64f9 to show that undef folding should already have dealt with that case.