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Factor dominator tree and frontier updating into SplitBlockPredecessors

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instead of doing it after every call.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50018 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-04-21 00:54:38 +00:00
parent 48a80b07bd
commit b85979434d
1 changed files with 14 additions and 18 deletions
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32
lib/Transforms/Utils/LoopSimplify.cpp
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@ -263,17 +263,18 @@ ReprocessLoop:
/// SplitBlockPredecessors - Split the specified block into two blocks. We want
/// to move the predecessors specified in the Preds list to point to the new
/// block, leaving the remaining predecessors pointing to BB. This method
/// updates the SSA PHINode's and AliasAnalysis, but no other analyses.
/// updates the SSA PHINode's, AliasAnalysis, DominatorTree and
/// DominanceFrontier, but no other analyses.
///
BasicBlock *LoopSimplify::SplitBlockPredecessors(BasicBlock *BB,
const char *Suffix,
const std::vector<BasicBlock*> &Preds) {
// Create new basic block, insert right before the original block...
// Create new basic block, insert right before the original block.
BasicBlock *NewBB =
BasicBlock::Create(BB->getName()+Suffix, BB->getParent(), BB);
// The preheader first gets an unconditional branch to the loop header...
// The preheader first gets an unconditional branch to the loop header.
BranchInst *BI = BranchInst::Create(BB, NewBB);
// For every PHI node in the block, insert a PHI node into NewBB where the
@ -288,6 +289,11 @@ BasicBlock *LoopSimplify::SplitBlockPredecessors(BasicBlock *BB,
// Insert dummy values as the incoming value...
PN->addIncoming(Constant::getNullValue(PN->getType()), NewBB);
}
DT->splitBlock(NewBB);
if (DominanceFrontier *DF = getAnalysisToUpdate<DominanceFrontier>())
DF->splitBlock(NewBB);
return NewBB;
}
@ -336,7 +342,7 @@ BasicBlock *LoopSimplify::SplitBlockPredecessors(BasicBlock *BB,
// If I is in NewBB, the Dominator call will fail, because NewBB isn't
// registered in DominatorTree yet. Handle this case explicitly.
if (!I || (I->getParent() != NewBB &&
getAnalysis<DominatorTree>().dominates(I, PN))) {
DT->dominates(I, PN))) {
PN->replaceAllUsesWith(V);
if (AA) AA->deleteValue(PN);
BB->getInstList().erase(PN);
@ -357,6 +363,10 @@ BasicBlock *LoopSimplify::SplitBlockPredecessors(BasicBlock *BB,
Preds[i]->setUnwindDest(NewBB);
}
DT->splitBlock(NewBB);
if (DominanceFrontier *DF = getAnalysisToUpdate<DominanceFrontier>())
DF->splitBlock(NewBB);
return NewBB;
}
@ -387,10 +397,6 @@ void LoopSimplify::InsertPreheaderForLoop(Loop *L) {
if (Loop *Parent = L->getParentLoop())
Parent->addBasicBlockToLoop(NewBB, LI->getBase());
DT->splitBlock(NewBB);
if (DominanceFrontier *DF = getAnalysisToUpdate<DominanceFrontier>())
DF->splitBlock(NewBB);
// Make sure that NewBB is put someplace intelligent, which doesn't mess up
// code layout too horribly.
PlaceSplitBlockCarefully(NewBB, OutsideBlocks, L);
@ -419,11 +425,6 @@ BasicBlock *LoopSimplify::RewriteLoopExitBlock(Loop *L, BasicBlock *Exit) {
if (SuccLoop)
SuccLoop->addBasicBlockToLoop(NewBB, LI->getBase());
// Update Dominator Information
DT->splitBlock(NewBB);
if (DominanceFrontier *DF = getAnalysisToUpdate<DominanceFrontier>())
DF->splitBlock(NewBB);
return NewBB;
}
@ -543,11 +544,6 @@ Loop *LoopSimplify::SeparateNestedLoop(Loop *L) {
BasicBlock *Header = L->getHeader();
BasicBlock *NewBB = SplitBlockPredecessors(Header, ".outer", OuterLoopPreds);
// Update dominator information
DT->splitBlock(NewBB);
if (DominanceFrontier *DF = getAnalysisToUpdate<DominanceFrontier>())
DF->splitBlock(NewBB);
// Make sure that NewBB is put someplace intelligent, which doesn't mess up
// code layout too horribly.
PlaceSplitBlockCarefully(NewBB, OuterLoopPreds, L);