diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp index aa31e0d850d..e79bdf75d40 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp @@ -926,7 +926,13 @@ Instruction *InstCombiner::foldAddWithConstant(BinaryOperator &Add) { if (Instruction *NV = foldBinOpIntoSelectOrPhi(Add)) return NV; - Value *X; + Value *X, *Y; + + // add (sub X, Y), -1 --> add (not Y), X + if (match(Op0, m_OneUse(m_Sub(m_Value(X), m_Value(Y)))) && + match(Op1, m_AllOnes())) + return BinaryOperator::CreateAdd(Builder.CreateNot(Y), X); + // zext(bool) + C -> bool ? C + 1 : C if (match(Op0, m_ZExt(m_Value(X))) && X->getType()->getScalarSizeInBits() == 1) |
