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Fix a bug where RecursivelyDeleteTriviallyDeadInstructions could

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delete the instruction pointed to by CGP's current instruction
iterator, leading to a crash on the testcase.  This fixes PR9578.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129200 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2011-04-09 07:05:44 +00:00
parent c3e4e59d10
commit 0403b473dd
2 changed files with 46 additions and 3 deletions
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21
lib/Transforms/Scalar/CodeGenPrepare.cpp
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@@ -889,11 +889,26 @@ bool CodeGenPrepare::OptimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
MemoryInst->replaceUsesOfWith(Repl, SunkAddr);
// If we have no uses, recursively delete the value and all dead instructions
// using it.
if (Repl->use_empty()) {
// This can cause recursive deletion, which can invalidate our iterator.
// Use a WeakVH to hold onto it in case this happens.
WeakVH IterHandle(CurInstIterator);
BasicBlock *BB = CurInstIterator->getParent();
RecursivelyDeleteTriviallyDeadInstructions(Repl);
// This address is now available for reassignment, so erase the table entry;
// we don't want to match some completely different instruction.
SunkAddrs[Addr] = 0;
if (IterHandle != CurInstIterator) {
// If the iterator instruction was recursively deleted, start over at the
// start of the block.
CurInstIterator = BB->begin();
SunkAddrs.clear();
} else {
// This address is now available for reassignment, so erase the table
// entry; we don't want to match some completely different instruction.
SunkAddrs[Addr] = 0;
}
}
++NumMemoryInsts;
return true;