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[SSAUpdater] Only iterate blocks modified by CheckIfPHIMatches() in RecordMatchingPHIs() #153596

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Merged
merged 1 commit into from
Aug 16, 2025
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[SSAUpdater] Only iterate blocks modified by CheckIfPHIMatches() in RecordMatchingPHIs() #153596

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26 changes: 13 additions & 13 deletions llvm/include/llvm/Transforms/Utils/SSAUpdaterImpl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -366,7 +366,7 @@ class SSAUpdaterImpl {
continue;

// Look for an existing PHI.
FindExistingPHI(Info->BB, BlockList);
FindExistingPHI(Info->BB);
if (Info->AvailableVal)
continue;

Expand Down Expand Up @@ -412,19 +412,19 @@ class SSAUpdaterImpl {

/// FindExistingPHI - Look through the PHI nodes in a block to see if any of
/// them match what is needed.
void FindExistingPHI(BlkT *BB, BlockListTy *BlockList) {
void FindExistingPHI(BlkT *BB) {
SmallVector<BBInfo *, 20> TaggedBlocks;
for (auto &SomePHI : BB->phis()) {
if (CheckIfPHIMatches(&SomePHI, TaggedBlocks)) {
RecordMatchingPHIs(BlockList);
RecordMatchingPHIs(TaggedBlocks);
break;
}
}
}

/// CheckIfPHIMatches - Check if a PHI node matches the placement and values
/// in the BBMap.
bool CheckIfPHIMatches(PhiT *PHI, SmallVectorImpl<BBInfo *> &TaggedBlocks) {
bool CheckIfPHIMatches(PhiT *PHI, BlockListTy &TaggedBlocks) {
// Match failed: clear all the PHITag values. Only need to clear visited
// blocks.
auto Cleanup = make_scope_exit([&]() {
Expand Down Expand Up @@ -484,15 +484,15 @@ class SSAUpdaterImpl {

/// RecordMatchingPHIs - For each PHI node that matches, record it in both
/// the BBMap and the AvailableVals mapping.
void RecordMatchingPHIs(BlockListTy *BlockList) {
for (typename BlockListTy::iterator I = BlockList->begin(),
E = BlockList->end(); I != E; ++I)
if (PhiT *PHI = (*I)->PHITag) {
BlkT *BB = PHI->getParent();
ValT PHIVal = Traits::GetPHIValue(PHI);
(*AvailableVals)[BB] = PHIVal;
BBMap[BB]->AvailableVal = PHIVal;
}
void RecordMatchingPHIs(BlockListTy &TaggedBlocks) {
for (BBInfo *Block : TaggedBlocks) {
PhiT *PHI = Block->PHITag;
assert(PHI && "PHITag didn't set?");
BlkT *BB = PHI->getParent();
ValT PHIVal = Traits::GetPHIValue(PHI);
(*AvailableVals)[BB] = PHIVal;
BBMap[BB]->AvailableVal = PHIVal;
}
}
};

Expand Down