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[InstCombine] In SimplifyMultipleUseDemandedBits, use a switch instead of cascaded ifs on opcode. NFC 

llvm-svn: 300085
This commit is contained in:
Craig Topper 2017-04-12 18:25:25 +00:00
parent 9a51c7f343
commit f35a7f7b49
1 changed files with 11 additions and 3 deletions
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14
llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
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@ -766,7 +766,8 @@ Value *InstCombiner::SimplifyMultipleUseDemandedBits(Instruction *I,
// context, we can at least compute the knownzero/knownone bits, and we can
// do simplifications that apply to *just* the one user if we know that
// this instruction has a simpler value in that context.
if (I->getOpcode() == Instruction::And) {
switch (I->getOpcode()) {
case Instruction::And:
// If either the LHS or the RHS are Zero, the result is zero.
computeKnownBits(I->getOperand(1), RHSKnownZero, RHSKnownOne, Depth + 1,
CxtI);
@ -787,7 +788,9 @@ Value *InstCombiner::SimplifyMultipleUseDemandedBits(Instruction *I,
if ((DemandedMask & (RHSKnownZero|LHSKnownZero)) == DemandedMask)
return Constant::getNullValue(ITy);
} else if (I->getOpcode() == Instruction::Or) {
break;
case Instruction::Or:
// We can simplify (X|Y) -> X or Y in the user's context if we know that
// only bits from X or Y are demanded.
@ -815,7 +818,10 @@ Value *InstCombiner::SimplifyMultipleUseDemandedBits(Instruction *I,
if ((DemandedMask & (~LHSKnownZero) & RHSKnownOne) ==
(DemandedMask & (~LHSKnownZero)))
return I->getOperand(1);
} else if (I->getOpcode() == Instruction::Xor) {
break;
case Instruction::Xor:
// We can simplify (X^Y) -> X or Y in the user's context if we know that
// only bits from X or Y are demanded.
@ -830,6 +836,8 @@ Value *InstCombiner::SimplifyMultipleUseDemandedBits(Instruction *I,
return I->getOperand(0);
if ((DemandedMask & LHSKnownZero) == DemandedMask)
return I->getOperand(1);
break;
}
// Compute the KnownZero/KnownOne bits to simplify things downstream.