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Clean up a bit.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29950 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2006-08-29 06:10:56 +00:00
parent 06abd22b1a
commit d648e140a5
1 changed files with 32 additions and 51 deletions
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83
lib/Transforms/Scalar/LoopUnroll.cpp
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@ -128,66 +128,47 @@ BasicBlock* LoopUnroll::FoldBlockIntoPredecessor(BasicBlock* BB) {
// pred, and if there is only one distinct successor of the predecessor, and
// if there are no PHI nodes.
//
pred_iterator PI(pred_begin(BB)), PE(pred_end(BB));
BasicBlock *OnlyPred = *PI++;
for (; PI != PE; ++PI) // Search all predecessors, see if they are all same
if (*PI != OnlyPred) {
OnlyPred = 0; // There are multiple different predecessors...
break;
}
BasicBlock *OnlyPred = BB->getSinglePredecessor();
if (!OnlyPred) return 0;
BasicBlock *OnlySucc = 0;
if (OnlyPred && OnlyPred != BB && // Don't break self loops
OnlyPred->getTerminator()->getOpcode() != Instruction::Invoke) {
// Check to see if there is only one distinct successor...
succ_iterator SI(succ_begin(OnlyPred)), SE(succ_end(OnlyPred));
OnlySucc = BB;
for (; SI != SE; ++SI)
if (*SI != OnlySucc) {
OnlySucc = 0; // There are multiple distinct successors!
break;
}
if (OnlyPred->getTerminator()->getNumSuccessors() != 1)
return 0;
DEBUG(std::cerr << "Merging: " << *BB << "into: " << *OnlyPred);
TerminatorInst *Term = OnlyPred->getTerminator();
// Resolve any PHI nodes at the start of the block. They are all
// guaranteed to have exactly one entry if they exist, unless there are
// multiple duplicate (but guaranteed to be equal) entries for the
// incoming edges. This occurs when there are multiple edges from
// OnlyPred to OnlySucc.
//
while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
PN->replaceAllUsesWith(PN->getIncomingValue(0));
BB->getInstList().pop_front(); // Delete the phi node...
}
if (OnlySucc) {
DEBUG(std::cerr << "Merging: " << *BB << "into: " << *OnlyPred);
TerminatorInst *Term = OnlyPred->getTerminator();
// Delete the unconditional branch from the predecessor...
OnlyPred->getInstList().pop_back();
// Resolve any PHI nodes at the start of the block. They are all
// guaranteed to have exactly one entry if they exist, unless there are
// multiple duplicate (but guaranteed to be equal) entries for the
// incoming edges. This occurs when there are multiple edges from
// OnlyPred to OnlySucc.
//
while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
PN->replaceAllUsesWith(PN->getIncomingValue(0));
BB->getInstList().pop_front(); // Delete the phi node...
}
// Move all definitions in the successor to the predecessor...
OnlyPred->getInstList().splice(OnlyPred->end(), BB->getInstList());
// Delete the unconditional branch from the predecessor...
OnlyPred->getInstList().pop_back();
// Make all PHI nodes that referred to BB now refer to Pred as their
// source...
BB->replaceAllUsesWith(OnlyPred);
// Move all definitions in the successor to the predecessor...
OnlyPred->getInstList().splice(OnlyPred->end(), BB->getInstList());
std::string OldName = BB->getName();
// Make all PHI nodes that referred to BB now refer to Pred as their
// source...
BB->replaceAllUsesWith(OnlyPred);
// Erase basic block from the function...
LI->removeBlock(BB);
BB->eraseFromParent();
std::string OldName = BB->getName();
// Inherit predecessors name if it exists...
if (!OldName.empty() && !OnlyPred->hasName())
OnlyPred->setName(OldName);
// Erase basic block from the function...
LI->removeBlock(BB);
BB->eraseFromParent();
// Inherit predecessors name if it exists...
if (!OldName.empty() && !OnlyPred->hasName())
OnlyPred->setName(OldName);
return OnlyPred;
}
return 0;
return OnlyPred;
}
bool LoopUnroll::visitLoop(Loop *L) {