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-rw-r--r--lib/VMCore/Instructions.cpp35
1 files changed, 17 insertions, 18 deletions
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index d479d9ac99..8250ec009d 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -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;