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Fix a nasty dangling-pointer heisenbug that could

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generate wrong code pretty much anywhere AFAICT.
A case that hits the bug reproducibly is impossible,
but the situation was like this:
Addr = ...
Store -> Addr
Addr2 = GEP , 0, 0
Store -> Addr2
Handling the first store, the code changed replaced Addr
with a sunkaddr and deleted Addr, but not its table
entry.  Code in OptimizedBlock replaced Addr2 with a
bitcast; if that happened to reuse the memory of Addr,
the old table entry was erroneously found when handling
the second store.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100044 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dale Johannesen
2010-03-31 20:37:15 +00:00
parent 4e86da71b3
commit 536d31b5b3
1 changed files with 5 additions and 1 deletions
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6
lib/Transforms/Scalar/CodeGenPrepare.cpp
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@@ -714,8 +714,12 @@ bool CodeGenPrepare::OptimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
MemoryInst->replaceUsesOfWith(Addr, SunkAddr); MemoryInst->replaceUsesOfWith(Addr, SunkAddr);
if (Addr->use_empty()) if (Addr->use_empty()) {
RecursivelyDeleteTriviallyDeadInstructions(Addr); RecursivelyDeleteTriviallyDeadInstructions(Addr);
// 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;
}
return true; return true;
} }