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[InstCombine] SimplifyDemandedUseBits - xor - refactor cast<ConstantInt> usage to PatternMatch. NFCI. 

First step towards replacing these to add full vector support.
This commit is contained in:
Simon Pilgrim 2020-10-15 15:23:34 +01:00
parent 2b45639ea0
commit b3330ae42c
1 changed files with 7 additions and 8 deletions
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15
llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
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@ -278,26 +278,25 @@ Value *InstCombinerImpl::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
// are flipping are known to be set, then the xor is just resetting those
// bits to zero. We can just knock out bits from the 'and' and the 'xor',
// simplifying both of them.
if (Instruction *LHSInst = dyn_cast<Instruction>(I->getOperand(0)))
if (Instruction *LHSInst = dyn_cast<Instruction>(I->getOperand(0))) {
ConstantInt *AndRHS, *XorRHS;
if (LHSInst->getOpcode() == Instruction::And && LHSInst->hasOneUse() &&
isa<ConstantInt>(I->getOperand(1)) &&
isa<ConstantInt>(LHSInst->getOperand(1)) &&
match(I->getOperand(1), m_ConstantInt(XorRHS)) &&
match(LHSInst->getOperand(1), m_ConstantInt(AndRHS)) &&
(LHSKnown.One & RHSKnown.One & DemandedMask) != 0) {
ConstantInt *AndRHS = cast<ConstantInt>(LHSInst->getOperand(1));
ConstantInt *XorRHS = cast<ConstantInt>(I->getOperand(1));
APInt NewMask = ~(LHSKnown.One & RHSKnown.One & DemandedMask);
Constant *AndC =
ConstantInt::get(I->getType(), NewMask & AndRHS->getValue());
ConstantInt::get(I->getType(), NewMask & AndRHS->getValue());
Instruction *NewAnd = BinaryOperator::CreateAnd(I->getOperand(0), AndC);
InsertNewInstWith(NewAnd, *I);
Constant *XorC =
ConstantInt::get(I->getType(), NewMask & XorRHS->getValue());
ConstantInt::get(I->getType(), NewMask & XorRHS->getValue());
Instruction *NewXor = BinaryOperator::CreateXor(NewAnd, XorC);
return InsertNewInstWith(NewXor, *I);
}
}
break;
}
case Instruction::Select: {