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[Attributor][FIX] Track change status for AAIsDead properly 

If we add a new live edge we need to indicate a change or otherwise the
new live block is not shown to users. Similarly, new known dead ends and
a changed `ToBeExploredFrom` set need to cause us to return CHANGED.
This commit is contained in:
Johannes Doerfert 2021-07-26 13:33:54 -05:00
parent ebe817f98c
commit 8befd05aad
1 changed files with 17 additions and 11 deletions
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28
llvm/lib/Transforms/IPO/AttributorAttributes.cpp
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@ -3836,10 +3836,8 @@ ChangeStatus AAIsDeadFunction::updateImpl(Attributor &A) {
// Fast forward for uninteresting instructions. We could look for UB here
// though.
while (!I->isTerminator() && !isa<CallBase>(I)) {
Change = ChangeStatus::CHANGED;
while (!I->isTerminator() && !isa<CallBase>(I))
I = I->getNextNode();
}
AliveSuccessors.clear();
@ -3872,11 +3870,11 @@ ChangeStatus AAIsDeadFunction::updateImpl(Attributor &A) {
if (UsedAssumedInformation) {
NewToBeExploredFrom.insert(I);
} else {
Change = ChangeStatus::CHANGED;
if (AliveSuccessors.empty() ||
(I->isTerminator() && AliveSuccessors.size() < I->getNumSuccessors()))
KnownDeadEnds.insert(I);
} else if (AliveSuccessors.empty() ||
(I->isTerminator() &&
AliveSuccessors.size() < I->getNumSuccessors())) {
if (KnownDeadEnds.insert(I))
Change = ChangeStatus::CHANGED;
}
LLVM_DEBUG(dbgs() << "[AAIsDead] #AliveSuccessors: "
@ -3890,15 +3888,23 @@ ChangeStatus AAIsDeadFunction::updateImpl(Attributor &A) {
Worklist.push_back(AliveSuccessor);
} else {
// record the assumed live edge
AssumedLiveEdges.insert(
std::make_pair(I->getParent(), AliveSuccessor->getParent()));
auto Edge = std::make_pair(I->getParent(), AliveSuccessor->getParent());
if (AssumedLiveEdges.insert(Edge).second)
Change = ChangeStatus::CHANGED;
if (assumeLive(A, *AliveSuccessor->getParent()))
Worklist.push_back(AliveSuccessor);
}
}
}
ToBeExploredFrom = std::move(NewToBeExploredFrom);
// Check if the content of ToBeExploredFrom changed, ignore the order.
if (NewToBeExploredFrom.size() != ToBeExploredFrom.size() ||
llvm::any_of(NewToBeExploredFrom, [&](const Instruction *I) {
return !ToBeExploredFrom.count(I);
})) {
Change = ChangeStatus::CHANGED;
ToBeExploredFrom = std::move(NewToBeExploredFrom);
}
// If we know everything is live there is no need to query for liveness.
// Instead, indicating a pessimistic fixpoint will cause the state to be