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[NFC][DebugInfo][RemoveDIs] Use iterators to insert in callsite-splitting #74455

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Merged
merged 1 commit into from
Dec 5, 2023
Merged

[NFC][DebugInfo][RemoveDIs] Use iterators to insert in callsite-splitting #74455

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8 changes: 4 additions & 4 deletions llvm/lib/Transforms/Scalar/CallSiteSplitting.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -372,10 +372,10 @@ static void splitCallSite(CallBase &CB,
return;
}

auto *OriginalBegin = &*TailBB->begin();
BasicBlock::iterator OriginalBegin = TailBB->begin();
// Replace users of the original call with a PHI mering call-sites split.
if (CallPN) {
CallPN->insertBefore(OriginalBegin);
CallPN->insertBefore(*TailBB, OriginalBegin);
CB.replaceAllUsesWith(CallPN);
}

Expand All @@ -399,13 +399,13 @@ static void splitCallSite(CallBase &CB,
for (auto &Mapping : ValueToValueMaps)
NewPN->addIncoming(Mapping[CurrentI],
cast<Instruction>(Mapping[CurrentI])->getParent());
NewPN->insertBefore(&*TailBB->begin());
NewPN->insertBefore(*TailBB, TailBB->begin());
CurrentI->replaceAllUsesWith(NewPN);
}
CurrentI->dropDbgValues();
CurrentI->eraseFromParent();
// We are done once we handled the first original instruction in TailBB.
if (CurrentI == OriginalBegin)
if (CurrentI == &*OriginalBegin)
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After being bitten by the buildbots: it turns out in the old version this was a comparison between a freed pointer and another pointer. Turning one of them into an iterator involves dereferencing it, it checking whether it's a sentinel, and subsequently asan firing because of a use-after-free.

break;
}
}
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