[PATCH] D113037: [InstCombine] (~a & b & c) | ~(a | b) -> (c | ~b) & ~a

[Stanislav Mekhanoshin via Phabricator via llvm-commits]

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  ----------------------------------------
  define i4 @src(i4 %a, i4 %b, i4 %c) {
  %0:
    %or1 = or i4 %b, %a
    %not1 = xor i4 %or1, 15
    %not2 = xor i4 %a, 15
    %and1 = and i4 %b, %not2
    %and2 = and i4 %and1, %c
    %or2 = or i4 %and2, %not1
    ret i4 %or2
  }
  =>
  define i4 @tgt(i4 %a, i4 %b, i4 %c) {
  %0:
    %notb = xor i4 %b, 15
    %or = or i4 %notb, %c
    %nota = xor i4 %a, 15
    %and = and i4 %or, %nota
    ret i4 %and
  }
  Transformation seems to be correct!


https://reviews.llvm.org/D113037

Files:
  llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
  llvm/test/Transforms/InstCombine/and-xor-or.ll

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