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various code cleanups, enhance MergeBlockIntoPredecessor to preserve 

loop info.

llvm-svn: 123074
This commit is contained in:
Chris Lattner 2011-01-08 19:08:40 +00:00
parent fee37c5fa3
commit 930b716e1b
1 changed files with 10 additions and 13 deletions
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23
llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
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@ -110,7 +110,7 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) {
if (isa<InvokeInst>(PredBB->getTerminator())) return false;
succ_iterator SI(succ_begin(PredBB)), SE(succ_end(PredBB));
BasicBlock* OnlySucc = BB;
BasicBlock *OnlySucc = BB;
for (; SI != SE; ++SI)
if (*SI != OnlySucc) {
OnlySucc = 0; // There are multiple distinct successors!
@ -131,10 +131,8 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) {
}
// Begin by getting rid of unneeded PHIs.
while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
PN->replaceAllUsesWith(PN->getIncomingValue(0));
BB->getInstList().pop_front(); // Delete the phi node...
}
if (isa<PHINode>(BB->front()))
FoldSingleEntryPHINodes(BB);
// Delete the unconditional branch from the predecessor...
PredBB->getInstList().pop_back();
@ -152,11 +150,9 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) {
// Finally, erase the old block and update dominator info.
if (P) {
if (DominatorTree* DT = P->getAnalysisIfAvailable<DominatorTree>()) {
DomTreeNode* DTN = DT->getNode(BB);
DomTreeNode* PredDTN = DT->getNode(PredBB);
if (DTN) {
if (DominatorTree *DT = P->getAnalysisIfAvailable<DominatorTree>()) {
if (DomTreeNode *DTN = DT->getNode(BB)) {
DomTreeNode *PredDTN = DT->getNode(PredBB);
SmallPtrSet<DomTreeNode*, 8> Children(DTN->begin(), DTN->end());
for (SmallPtrSet<DomTreeNode*, 8>::iterator DI = Children.begin(),
DE = Children.end(); DI != DE; ++DI)
@ -164,12 +160,13 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) {
DT->eraseNode(BB);
}
if (LoopInfo *LI = P->getAnalysisIfAvailable<LoopInfo>())
LI->removeBlock(BB);
}
}
BB->eraseFromParent();
return true;
}
@ -276,7 +273,7 @@ BasicBlock *llvm::SplitBlock(BasicBlock *Old, Instruction *SplitPt, Pass *P) {
// The new block lives in whichever loop the old one did. This preserves
// LCSSA as well, because we force the split point to be after any PHI nodes.
if (LoopInfo* LI = P->getAnalysisIfAvailable<LoopInfo>())
if (LoopInfo *LI = P->getAnalysisIfAvailable<LoopInfo>())
if (Loop *L = LI->getLoopFor(Old))
L->addBasicBlockToLoop(New, LI->getBase());