improve comments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53531 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-07-13 21:55:46 +00:00
parent 867661ac8b
commit eb388af89f

View File

@ -1538,6 +1538,9 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) {
PHINode *NewPN = PHINode::Create(Type::Int1Ty,
BI->getCondition()->getName() + ".pr",
BB->begin());
// Okay, we're going to insert the PHI node. Since PBI is not the only
// predecessor, compute the PHI'd conditional value for all of the preds.
// Any predecessor where the condition is not computable we keep symbolic.
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
if ((PBI = dyn_cast<BranchInst>((*PI)->getTerminator())) &&
PBI != BI && PBI->isConditional() &&
@ -1551,7 +1554,6 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) {
}
BI->setCondition(NewPN);
// This will thread the branch.
return true;
}
}
@ -1653,7 +1655,7 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) {
// them agree.
for (BasicBlock::iterator II = CommonDest->begin();
(PN = dyn_cast<PHINode>(II)); ++II) {
Value * BIV = PN->getIncomingValueForBlock(BB);
Value *BIV = PN->getIncomingValueForBlock(BB);
unsigned PBBIdx = PN->getBasicBlockIndex(PBI->getParent());
Value *PBIV = PN->getIncomingValue(PBBIdx);
if (BIV != PBIV) {