diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp | 6 | ||||
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp | 6 |
2 files changed, 5 insertions, 7 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index f2f174e5c24..fdc9c373b95 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -1285,13 +1285,9 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) { return replaceInstUsesWith(I, V); if (match(Op1, m_One())) { - Value *X; - // (0 - x) & 1 --> x & 1 - if (match(Op0, m_Sub(m_Zero(), m_Value(X)))) - return BinaryOperator::CreateAnd(X, Op1); - // (1 << x) & 1 --> zext(x == 0) // (1 >> x) & 1 --> zext(x == 0) + Value *X; if (match(Op0, m_OneUse(m_LogicalShift(m_One(), m_Value(X))))) { Value *IsZero = Builder.CreateICmpEQ(X, ConstantInt::get(I.getType(), 0)); return new ZExtInst(IsZero, I.getType()); diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp index 5689c060423..a20f474cbf4 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp @@ -417,8 +417,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, // the highest demanded bit, we just return the other side. if (DemandedFromOps.isSubsetOf(RHSKnown.Zero)) return I->getOperand(0); - // We can't do this with the LHS for subtraction. - if (I->getOpcode() == Instruction::Add && + // We can't do this with the LHS for subtraction, unless we are only + // demanding the LSB. + if ((I->getOpcode() == Instruction::Add || + DemandedFromOps.isOneValue()) && DemandedFromOps.isSubsetOf(LHSKnown.Zero)) return I->getOperand(1); } |
