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tidy up

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llvm-svn: 82489
This commit is contained in:
Chris Lattner 2009-09-21 22:27:34 +00:00
parent f5afe18457
commit 78d19af97a
1 changed files with 17 additions and 18 deletions
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35
lib/VMCore/Instructions.cpp
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@ -234,12 +234,11 @@ void PHINode::resizeOperands(unsigned NumOps) {
/// otherwise use DT to test for dominance.
///
Value *PHINode::hasConstantValue(DominatorTree *DT) const {
// If the PHI node only has one incoming value, eliminate the PHI node...
// If the PHI node only has one incoming value, eliminate the PHI node.
if (getNumIncomingValues() == 1) {
if (getIncomingValue(0) != this) // not X = phi X
return getIncomingValue(0);
else
return UndefValue::get(getType()); // Self cycle is dead.
return UndefValue::get(getType()); // Self cycle is dead.
}
// Otherwise if all of the incoming values are the same for the PHI, replace
@ -253,8 +252,7 @@ Value *PHINode::hasConstantValue(DominatorTree *DT) const {
} else if (getIncomingValue(i) != this) { // Not the PHI node itself...
if (InVal && getIncomingValue(i) != InVal)
return 0; // Not the same, bail out.
else
InVal = getIncomingValue(i);
InVal = getIncomingValue(i);
}
// The only case that could cause InVal to be null is if we have a PHI node
@ -267,19 +265,20 @@ Value *PHINode::hasConstantValue(DominatorTree *DT) const {
// instruction, we cannot always return X as the result of the PHI node. Only
// do this if X is not an instruction (thus it must dominate the PHI block),
// or if the client is prepared to deal with this possibility.
if (HasUndefInput)
if (Instruction *IV = dyn_cast<Instruction>(InVal)) {
if (DT) {
// We have a DominatorTree. Do a precise test.
if (!DT->dominates(IV, this))
return 0;
} else {
// If it's in the entry block, it dominates everything.
if (IV->getParent() != &IV->getParent()->getParent()->getEntryBlock() ||
isa<InvokeInst>(IV))
return 0; // Cannot guarantee that InVal dominates this PHINode.
}
}
if (!HasUndefInput || !isa<Instruction>(InVal))
return InVal;
Instruction *IV = cast<Instruction>(InVal);
if (DT) {
// We have a DominatorTree. Do a precise test.
if (!DT->dominates(IV, this))
return 0;
} else {
// If it is in the entry block, it obviously dominates everything.
if (IV->getParent() != &IV->getParent()->getParent()->getEntryBlock() ||
isa<InvokeInst>(IV))
return 0; // Cannot guarantee that InVal dominates this PHINode.
}
// All of the incoming values are the same, return the value now.
return InVal;