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Remove an instance where the 'unwind' instruction was created.

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The 'unwind' instruction was acting essentially as a placeholder, because it
would be replaced at the end of this function by a branch to the "unwind
handler". The 'unwind' instruction is going away, so use 'unreachable' instead,
which serves the same purpose as a placeholder.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137098 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2011-08-09 01:09:21 +00:00
parent a2b552d0ae
commit 4fa93b7ce1
1 changed files with 10 additions and 2 deletions
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12
lib/Transforms/Utils/LowerInvoke.cpp
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@ -406,6 +406,7 @@ bool LowerInvoke::insertExpensiveEHSupport(Function &F) {
SmallVector<ReturnInst*,16> Returns;
SmallVector<UnwindInst*,16> Unwinds;
SmallVector<InvokeInst*,16> Invokes;
SmallVector<UnreachableInst*, 16> Unreachables;
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
@ -486,9 +487,10 @@ bool LowerInvoke::insertExpensiveEHSupport(Function &F) {
// Insert a load in the Catch block, and a switch on its value. By default,
// we go to a block that just does an unwind (which is the correct action
// for a standard call).
// for a standard call). We insert an unreachable instruction here and
// modify the block to jump to the correct unwinding pad later.
BasicBlock *UnwindBB = BasicBlock::Create(F.getContext(), "unwindbb", &F);
Unwinds.push_back(new UnwindInst(F.getContext(), UnwindBB));
Unreachables.push_back(new UnreachableInst(F.getContext(), UnwindBB));
Value *CatchLoad = new LoadInst(InvokeNum, "invoke.num", true, CatchBB);
SwitchInst *CatchSwitch =
@ -577,6 +579,12 @@ bool LowerInvoke::insertExpensiveEHSupport(Function &F) {
Unwinds[i]->eraseFromParent();
}
// Replace all inserted unreachables with a branch to the unwind handler.
for (unsigned i = 0, e = Unreachables.size(); i != e; ++i) {
BranchInst::Create(UnwindHandler, Unreachables[i]);
Unreachables[i]->eraseFromParent();
}
// Finally, for any returns from this function, if this function contains an
// invoke, restore the old jmpbuf pointer to its input value.
if (OldJmpBufPtr) {