Factor code out into the Utils library

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10530 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-12-19 05:58:40 +00:00
parent abbc2dd779
commit 60921c9aa1

View File

@ -1906,29 +1906,9 @@ bool InstCombiner::transformConstExprCastCall(CallSite CS) {
// PHINode simplification
//
Instruction *InstCombiner::visitPHINode(PHINode &PN) {
// If the PHI node only has one incoming value, eliminate the PHI node...
if (PN.getNumIncomingValues() == 1)
return ReplaceInstUsesWith(PN, PN.getIncomingValue(0));
// Otherwise if all of the incoming values are the same for the PHI, replace
// the PHI node with the incoming value.
//
Value *InVal = 0;
for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i)
if (PN.getIncomingValue(i) != &PN) // Not the PHI node itself...
if (InVal && PN.getIncomingValue(i) != InVal)
return 0; // Not the same, bail out.
else
InVal = PN.getIncomingValue(i);
// The only case that could cause InVal to be null is if we have a PHI node
// that only has entries for itself. In this case, there is no entry into the
// loop, so kill the PHI.
//
if (InVal == 0) InVal = Constant::getNullValue(PN.getType());
// All of the incoming values are the same, replace the PHI node now.
return ReplaceInstUsesWith(PN, InVal);
if (Value *V = hasConstantValue(&PN))
return ReplaceInstUsesWith(PN, V);
return 0;
}