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Firstly, having a BranchInst isn't exclusive with having an unwind_to.

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Secondly, we have to check whether the branch is actually pointing to the block
with the unwind in it. We could have gotten here because of the unwind_to alone.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48099 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2008-03-09 07:50:37 +00:00
parent 8dc023f684
commit 3f4cc3101e
2 changed files with 26 additions and 5 deletions
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13
lib/Transforms/Utils/SimplifyCFG.cpp
View File

@ -1364,13 +1364,19 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
SmallVector<BasicBlock*, 8> Preds(pred_begin(BB), pred_end(BB));
while (!Preds.empty()) {
BasicBlock *Pred = Preds.back();
if (Pred->getUnwindDest() == BB) {
Pred->setUnwindDest(NULL);
Changed = true;
}
if (BranchInst *BI = dyn_cast<BranchInst>(Pred->getTerminator())) {
if (BI->isUnconditional()) {
if (BI->isUnconditional() && BI->getSuccessor(0) == BB) {
Pred->getInstList().pop_back(); // nuke uncond branch
new UnwindInst(Pred); // Use unwind.
Changed = true;
}
} else if (InvokeInst *II = dyn_cast<InvokeInst>(Pred->getTerminator())) {
} 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...
@ -1388,9 +1394,6 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
delete II;
Changed = true;
}
} else if (Pred->getUnwindDest() == BB) {
Pred->setUnwindDest(NULL);
}
Preds.pop_back();
}

18
test/Transforms/SimplifyCFG/unwindto.ll
View File

@ -41,3 +41,21 @@ entry: unwind_to %cleanup
cleanup:
unwind
}
define i32 @f4() {
entry: unwind_to %cleanup
call void @g(i32 0)
br label %cleanup
cleanup:
unwind
}
define i32 @f5() {
entry: unwind_to %cleanup
call void @g(i32 0)
br label %other
other:
ret i32 0
cleanup:
unwind
}