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[DFAJumpThreading][NFC] Clear cleanPhiNodes and phi-related code #162423

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Merged
merged 2 commits into from
Oct 8, 2025
Merged

[DFAJumpThreading][NFC] Clear cleanPhiNodes and phi-related code #162423

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[DFAJumpThreading][NFC] Clear cleanPhiNodes and phi-related code
XChy Oct 7, 2025
de4a96b
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XChy Oct 8, 2025
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35 changes: 13 additions & 22 deletions llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1195,19 +1195,18 @@ struct TransformDFA {
// value for the new predecessor ClonedBB. The value will either be the same
// value from BB or a cloned value.
for (BasicBlock *Succ : BlocksToUpdate) {
for (auto II = Succ->begin(); PHINode *Phi = dyn_cast<PHINode>(II);
++II) {
Value *Incoming = Phi->getIncomingValueForBlock(BB);
for (PHINode &Phi : Succ->phis()) {
Value *Incoming = Phi.getIncomingValueForBlock(BB);
if (Incoming) {
if (isa<Constant>(Incoming)) {
Phi->addIncoming(Incoming, ClonedBB);
Phi.addIncoming(Incoming, ClonedBB);
continue;
}
Value *ClonedVal = VMap[Incoming];
if (ClonedVal)
Phi->addIncoming(ClonedVal, ClonedBB);
Phi.addIncoming(ClonedVal, ClonedBB);
else
Phi->addIncoming(Incoming, ClonedBB);
Phi.addIncoming(Incoming, ClonedBB);
}
}
}
Expand Down Expand Up @@ -1302,27 +1301,19 @@ struct TransformDFA {
void cleanPhiNodes(BasicBlock *BB) {
// If BB is no longer reachable, remove any remaining phi nodes
if (pred_empty(BB)) {
std::vector<PHINode *> PhiToRemove;
for (auto II = BB->begin(); PHINode *Phi = dyn_cast<PHINode>(II); ++II) {
PhiToRemove.push_back(Phi);
}
for (PHINode *PN : PhiToRemove) {
PN->replaceAllUsesWith(PoisonValue::get(PN->getType()));
PN->eraseFromParent();
for (PHINode &PN : make_early_inc_range(BB->phis())) {
PN.replaceAllUsesWith(PoisonValue::get(PN.getType()));
PN.eraseFromParent();
}
return;
}

// Remove any incoming values that come from an invalid predecessor
for (auto II = BB->begin(); PHINode *Phi = dyn_cast<PHINode>(II); ++II) {
std::vector<BasicBlock *> BlocksToRemove;
for (BasicBlock *IncomingBB : Phi->blocks()) {
if (!isPredecessor(BB, IncomingBB))
BlocksToRemove.push_back(IncomingBB);
}
for (BasicBlock *BB : BlocksToRemove)
Phi->removeIncomingValue(BB);
}
for (PHINode &Phi : BB->phis())
Phi.removeIncomingValueIf([&](unsigned Index) {
BasicBlock *IncomingBB = Phi.getIncomingBlock(Index);
return !isPredecessor(BB, IncomingBB);
});
}

/// Checks if BB was already cloned for a particular next state value. If it
Expand Down