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Rewrite another SSAUpdater function to avoid recursion. 

llvm-svn: 100147
This commit is contained in:
Bob Wilson 2010-04-01 23:05:58 +00:00
parent 5342ddaadf
commit 37b73d9d3e
2 changed files with 50 additions and 36 deletions
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4
llvm/include/llvm/Transforms/Utils/SSAUpdater.h
View File

@ -108,8 +108,8 @@ private:
void FindPHIPlacement(BasicBlock *BB, BBInfo *Info, bool &Changed,
unsigned Counter);
void FindAvailableVal(BasicBlock *BB, BBInfo *Info, unsigned Counter);
void FindExistingPHI(BasicBlock *BB, BBInfo *Info);
bool CheckIfPHIMatches(BasicBlock *BB, BBInfo *Info, Value *Val);
void FindExistingPHI(BasicBlock *BB);
bool CheckIfPHIMatches(PHINode *PHI);
void RecordMatchingPHI(PHINode *PHI);
void ClearPHITags(PHINode *PHI);

82
llvm/lib/Transforms/Utils/SSAUpdater.cpp
View File

@ -366,7 +366,7 @@ void SSAUpdater::FindAvailableVal(BasicBlock *BB, BBInfo *Info,
PHINode *NewPHI = 0;
if (Info->DefBB == BB) {
// Look for an existing PHI.
FindExistingPHI(BB, Info);
FindExistingPHI(BB);
if (!Info->AvailableVal) {
NewPHI = PHINode::Create(PrototypeValue->getType(),
PrototypeValue->getName(), &BB->front());
@ -401,11 +401,11 @@ void SSAUpdater::FindAvailableVal(BasicBlock *BB, BBInfo *Info,
/// FindExistingPHI - Look through the PHI nodes in a block to see if any of
/// them match what is needed.
void SSAUpdater::FindExistingPHI(BasicBlock *BB, BBInfo *Info) {
void SSAUpdater::FindExistingPHI(BasicBlock *BB) {
PHINode *SomePHI;
for (BasicBlock::iterator It = BB->begin();
(SomePHI = dyn_cast<PHINode>(It)); ++It) {
if (CheckIfPHIMatches(BB, Info, SomePHI)) {
if (CheckIfPHIMatches(SomePHI)) {
RecordMatchingPHI(SomePHI);
break;
}
@ -413,40 +413,54 @@ void SSAUpdater::FindExistingPHI(BasicBlock *BB, BBInfo *Info) {
}
}
/// CheckIfPHIMatches - Check if Val is a PHI node in block BB that matches
/// the placement and values in the BBMap.
bool SSAUpdater::CheckIfPHIMatches(BasicBlock *BB, BBInfo *Info, Value *Val) {
if (Info->AvailableVal)
return Val == Info->AvailableVal;
// Check if Val is a PHI in this block.
PHINode *PHI = dyn_cast<PHINode>(Val);
if (!PHI || PHI->getParent() != BB)
return false;
// If this block has already been visited, check if this PHI matches.
if (Info->PHITag)
return PHI == Info->PHITag;
Info->PHITag = PHI;
bool IsMatch = true;
// Iterate through the predecessors.
/// CheckIfPHIMatches - Check if a PHI node matches the placement and values
/// in the BBMap.
bool SSAUpdater::CheckIfPHIMatches(PHINode *PHI) {
BBMapTy *BBMap = getBBMap(BM);
for (unsigned i = 0, e = PHI->getNumIncomingValues(); i != e; ++i) {
BasicBlock *Pred = PHI->getIncomingBlock(i);
Value *IncomingVal = PHI->getIncomingValue(i);
BBInfo *PredInfo = (*BBMap)[Pred];
// Skip to the nearest preceding definition.
if (PredInfo->DefBB != Pred) {
Pred = PredInfo->DefBB;
PredInfo = (*BBMap)[Pred];
}
if (!CheckIfPHIMatches(Pred, PredInfo, IncomingVal)) {
IsMatch = false;
break;
SmallVector<PHINode*, 20> WorkList;
WorkList.push_back(PHI);
// Mark that the block containing this PHI has been visited.
(*BBMap)[PHI->getParent()]->PHITag = PHI;
while (!WorkList.empty()) {
PHI = WorkList.pop_back_val();
// Iterate through the PHI's incoming values.
for (unsigned i = 0, e = PHI->getNumIncomingValues(); i != e; ++i) {
Value *IncomingVal = PHI->getIncomingValue(i);
BasicBlock *Pred = PHI->getIncomingBlock(i);
BBInfo *PredInfo = (*BBMap)[Pred];
// Skip to the nearest preceding definition.
if (PredInfo->DefBB != Pred) {
Pred = PredInfo->DefBB;
PredInfo = (*BBMap)[Pred];
}
// Check if it matches the expected value.
if (PredInfo->AvailableVal) {
if (IncomingVal == PredInfo->AvailableVal)
continue;
return false;
}
// Check if the value is a PHI in the correct block.
PHINode *IncomingPHIVal = dyn_cast<PHINode>(IncomingVal);
if (!IncomingPHIVal || IncomingPHIVal->getParent() != Pred)
return false;
// If this block has already been visited, check if this PHI matches.
if (PredInfo->PHITag) {
if (IncomingPHIVal == PredInfo->PHITag)
continue;
return false;
}
PredInfo->PHITag = IncomingPHIVal;
WorkList.push_back(IncomingPHIVal);
}
}
return IsMatch;
return true;
}
/// RecordMatchingPHI - For a PHI node that matches, record it and its input