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Implement SimplifyCFG/BrUnwind.ll

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@15022 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-07-20 01:17:38 +00:00
parent c6c9db2fd7
commit af17b1df84
1 changed files with 9 additions and 2 deletions
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11
lib/Transforms/Utils/SimplifyCFG.cpp
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@ -764,12 +764,19 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
} else if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->begin())) {
// Check to see if the first instruction in this block is just an unwind.
// If so, replace any invoke instructions which use this as an exception
// destination with call instructions.
// destination with call instructions, and any unconditional branch
// predecessor with an unwind.
//
std::vector<BasicBlock*> Preds(pred_begin(BB), pred_end(BB));
while (!Preds.empty()) {
BasicBlock *Pred = Preds.back();
if (InvokeInst *II = dyn_cast<InvokeInst>(Pred->getTerminator()))
if (BranchInst *BI = dyn_cast<BranchInst>(Pred->getTerminator())) {
if (BI->isUnconditional()) {
Pred->getInstList().pop_back(); // nuke uncond branch
new UnwindInst(Pred); // Use unwind.
Changed = true;
}
} else if (InvokeInst *II = dyn_cast<InvokeInst>(Pred->getTerminator()))
if (II->getUnwindDest() == BB) {
// Insert a new branch instruction before the invoke, because this
// is now a fall through...