diff options
Diffstat (limited to 'lib/Transforms/Utils/SSAUpdater.cpp')
| -rw-r--r-- | lib/Transforms/Utils/SSAUpdater.cpp | 497 |
1 files changed, 183 insertions, 314 deletions
diff --git a/lib/Transforms/Utils/SSAUpdater.cpp b/lib/Transforms/Utils/SSAUpdater.cpp index 292332e4f8a60..a31235a1f5cb3 100644 --- a/lib/Transforms/Utils/SSAUpdater.cpp +++ b/lib/Transforms/Utils/SSAUpdater.cpp @@ -14,82 +14,31 @@ #include "llvm/Transforms/Utils/SSAUpdater.h" #include "llvm/Instructions.h" #include "llvm/ADT/DenseMap.h" -#include "llvm/Support/AlignOf.h" -#include "llvm/Support/Allocator.h" #include "llvm/Support/CFG.h" #include "llvm/Support/Debug.h" +#include "llvm/Support/ValueHandle.h" #include "llvm/Support/raw_ostream.h" using namespace llvm; -/// BBInfo - Per-basic block information used internally by SSAUpdater. -/// The predecessors of each block are cached here since pred_iterator is -/// slow and we need to iterate over the blocks at least a few times. -class SSAUpdater::BBInfo { -public: - Value *AvailableVal; // Value to use in this block. - BasicBlock *DefBB; // Block that defines the available value. - unsigned NumPreds; // Number of predecessor blocks. - BasicBlock **Preds; // Array[NumPreds] of predecessor blocks. - unsigned Counter; // Marker to identify blocks already visited. - PHINode *PHITag; // Marker for existing PHIs that match. - - BBInfo(BasicBlock *BB, Value *V, BumpPtrAllocator *Allocator); -}; -typedef DenseMap<BasicBlock*, SSAUpdater::BBInfo*> BBMapTy; - -SSAUpdater::BBInfo::BBInfo(BasicBlock *BB, Value *V, - BumpPtrAllocator *Allocator) - : AvailableVal(V), DefBB(0), NumPreds(0), Preds(0), Counter(0), PHITag(0) { - // If this block has a known value, don't bother finding its predecessors. - if (V) { - DefBB = BB; - return; - } - - // We can get our predecessor info by walking the pred_iterator list, but it - // is relatively slow. If we already have PHI nodes in this block, walk one - // of them to get the predecessor list instead. - if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin())) { - NumPreds = SomePhi->getNumIncomingValues(); - Preds = static_cast<BasicBlock**> - (Allocator->Allocate(NumPreds * sizeof(BasicBlock*), - AlignOf<BasicBlock*>::Alignment)); - for (unsigned pi = 0; pi != NumPreds; ++pi) - Preds[pi] = SomePhi->getIncomingBlock(pi); - return; - } - - // Stash the predecessors in a temporary vector until we know how much space - // to allocate for them. - SmallVector<BasicBlock*, 10> TmpPreds; - for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) { - TmpPreds.push_back(*PI); - ++NumPreds; - } - Preds = static_cast<BasicBlock**> - (Allocator->Allocate(NumPreds * sizeof(BasicBlock*), - AlignOf<BasicBlock*>::Alignment)); - memcpy(Preds, TmpPreds.data(), NumPreds * sizeof(BasicBlock*)); -} +typedef DenseMap<BasicBlock*, TrackingVH<Value> > AvailableValsTy; +typedef std::vector<std::pair<BasicBlock*, TrackingVH<Value> > > + IncomingPredInfoTy; -typedef DenseMap<BasicBlock*, Value*> AvailableValsTy; static AvailableValsTy &getAvailableVals(void *AV) { return *static_cast<AvailableValsTy*>(AV); } -static BBMapTy *getBBMap(void *BM) { - return static_cast<BBMapTy*>(BM); +static IncomingPredInfoTy &getIncomingPredInfo(void *IPI) { + return *static_cast<IncomingPredInfoTy*>(IPI); } -static BumpPtrAllocator *getAllocator(void *BPA) { - return static_cast<BumpPtrAllocator*>(BPA); -} SSAUpdater::SSAUpdater(SmallVectorImpl<PHINode*> *NewPHI) - : AV(0), PrototypeValue(0), BM(0), BPA(0), InsertedPHIs(NewPHI) {} + : AV(0), PrototypeValue(0), IPI(0), InsertedPHIs(NewPHI) {} SSAUpdater::~SSAUpdater() { delete &getAvailableVals(AV); + delete &getIncomingPredInfo(IPI); } /// Initialize - Reset this object to get ready for a new set of SSA @@ -99,6 +48,11 @@ void SSAUpdater::Initialize(Value *ProtoValue) { AV = new AvailableValsTy(); else getAvailableVals(AV).clear(); + + if (IPI == 0) + IPI = new IncomingPredInfoTy(); + else + getIncomingPredInfo(IPI).clear(); PrototypeValue = ProtoValue; } @@ -119,7 +73,7 @@ void SSAUpdater::AddAvailableValue(BasicBlock *BB, Value *V) { /// IsEquivalentPHI - Check if PHI has the same incoming value as specified /// in ValueMapping for each predecessor block. -static bool IsEquivalentPHI(PHINode *PHI, +static bool IsEquivalentPHI(PHINode *PHI, DenseMap<BasicBlock*, Value*> &ValueMapping) { unsigned PHINumValues = PHI->getNumIncomingValues(); if (PHINumValues != ValueMapping.size()) @@ -135,12 +89,38 @@ static bool IsEquivalentPHI(PHINode *PHI, return true; } +/// GetExistingPHI - Check if BB already contains a phi node that is equivalent +/// to the specified mapping from predecessor blocks to incoming values. +static Value *GetExistingPHI(BasicBlock *BB, + DenseMap<BasicBlock*, Value*> &ValueMapping) { + PHINode *SomePHI; + for (BasicBlock::iterator It = BB->begin(); + (SomePHI = dyn_cast<PHINode>(It)); ++It) { + if (IsEquivalentPHI(SomePHI, ValueMapping)) + return SomePHI; + } + return 0; +} + +/// GetExistingPHI - Check if BB already contains an equivalent phi node. +/// The InputIt type must be an iterator over std::pair<BasicBlock*, Value*> +/// objects that specify the mapping from predecessor blocks to incoming values. +template<typename InputIt> +static Value *GetExistingPHI(BasicBlock *BB, const InputIt &I, + const InputIt &E) { + // Avoid create the mapping if BB has no phi nodes at all. + if (!isa<PHINode>(BB->begin())) + return 0; + DenseMap<BasicBlock*, Value*> ValueMapping(I, E); + return GetExistingPHI(BB, ValueMapping); +} + /// GetValueAtEndOfBlock - Construct SSA form, materializing a value that is /// live at the end of the specified block. Value *SSAUpdater::GetValueAtEndOfBlock(BasicBlock *BB) { - assert(BM == 0 && BPA == 0 && "Unexpected Internal State"); + assert(getIncomingPredInfo(IPI).empty() && "Unexpected Internal State"); Value *Res = GetValueAtEndOfBlockInternal(BB); - assert(BM == 0 && BPA == 0 && "Unexpected Internal State"); + assert(getIncomingPredInfo(IPI).empty() && "Unexpected Internal State"); return Res; } @@ -166,7 +146,7 @@ Value *SSAUpdater::GetValueAtEndOfBlock(BasicBlock *BB) { Value *SSAUpdater::GetValueInMiddleOfBlock(BasicBlock *BB) { // If there is no definition of the renamed variable in this block, just use // GetValueAtEndOfBlock to do our work. - if (!HasValueForBlock(BB)) + if (!getAvailableVals(AV).count(BB)) return GetValueAtEndOfBlock(BB); // Otherwise, we have the hard case. Get the live-in values for each @@ -213,18 +193,10 @@ Value *SSAUpdater::GetValueInMiddleOfBlock(BasicBlock *BB) { if (SingularValue != 0) return SingularValue; - // Otherwise, we do need a PHI: check to see if we already have one available - // in this block that produces the right value. - if (isa<PHINode>(BB->begin())) { - DenseMap<BasicBlock*, Value*> ValueMapping(PredValues.begin(), - PredValues.end()); - PHINode *SomePHI; - for (BasicBlock::iterator It = BB->begin(); - (SomePHI = dyn_cast<PHINode>(It)); ++It) { - if (IsEquivalentPHI(SomePHI, ValueMapping)) - return SomePHI; - } - } + // Otherwise, we do need a PHI. + if (Value *ExistingPHI = GetExistingPHI(BB, PredValues.begin(), + PredValues.end())) + return ExistingPHI; // Ok, we have no way out, insert a new one now. PHINode *InsertedPHI = PHINode::Create(PrototypeValue->getType(), @@ -254,7 +226,7 @@ Value *SSAUpdater::GetValueInMiddleOfBlock(BasicBlock *BB) { /// which use their value in the corresponding predecessor. void SSAUpdater::RewriteUse(Use &U) { Instruction *User = cast<Instruction>(U.getUser()); - + Value *V; if (PHINode *UserPN = dyn_cast<PHINode>(User)) V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U)); @@ -264,264 +236,161 @@ void SSAUpdater::RewriteUse(Use &U) { U.set(V); } + /// GetValueAtEndOfBlockInternal - Check to see if AvailableVals has an entry /// for the specified BB and if so, return it. If not, construct SSA form by -/// first calculating the required placement of PHIs and then inserting new -/// PHIs where needed. +/// walking predecessors inserting PHI nodes as needed until we get to a block +/// where the value is available. +/// Value *SSAUpdater::GetValueAtEndOfBlockInternal(BasicBlock *BB) { AvailableValsTy &AvailableVals = getAvailableVals(AV); - if (Value *V = AvailableVals[BB]) - return V; - - // Pool allocation used internally by GetValueAtEndOfBlock. - BumpPtrAllocator AllocatorObj; - BBMapTy BBMapObj; - BPA = &AllocatorObj; - BM = &BBMapObj; - - BBInfo *Info = new (AllocatorObj) BBInfo(BB, 0, &AllocatorObj); - BBMapObj[BB] = Info; - - bool Changed; - unsigned Counter = 1; - do { - Changed = false; - FindPHIPlacement(BB, Info, Changed, Counter); - ++Counter; - } while (Changed); - - FindAvailableVal(BB, Info, Counter); - - BPA = 0; - BM = 0; - return Info->AvailableVal; -} -/// FindPHIPlacement - Recursively visit the predecessors of a block to find -/// the reaching definition for each predecessor and then determine whether -/// a PHI is needed in this block. -void SSAUpdater::FindPHIPlacement(BasicBlock *BB, BBInfo *Info, bool &Changed, - unsigned Counter) { - AvailableValsTy &AvailableVals = getAvailableVals(AV); - BBMapTy *BBMap = getBBMap(BM); - BumpPtrAllocator *Allocator = getAllocator(BPA); - bool BBNeedsPHI = false; - BasicBlock *SamePredDefBB = 0; - - // If there are no predecessors, then we must have found an unreachable - // block. Treat it as a definition with 'undef'. - if (Info->NumPreds == 0) { - Info->AvailableVal = UndefValue::get(PrototypeValue->getType()); - Info->DefBB = BB; - return; + // Query AvailableVals by doing an insertion of null. + std::pair<AvailableValsTy::iterator, bool> InsertRes = + AvailableVals.insert(std::make_pair(BB, TrackingVH<Value>())); + + // Handle the case when the insertion fails because we have already seen BB. + if (!InsertRes.second) { + // If the insertion failed, there are two cases. The first case is that the + // value is already available for the specified block. If we get this, just + // return the value. + if (InsertRes.first->second != 0) + return InsertRes.first->second; + + // Otherwise, if the value we find is null, then this is the value is not + // known but it is being computed elsewhere in our recursion. This means + // that we have a cycle. Handle this by inserting a PHI node and returning + // it. When we get back to the first instance of the recursion we will fill + // in the PHI node. + return InsertRes.first->second = + PHINode::Create(PrototypeValue->getType(), PrototypeValue->getName(), + &BB->front()); } - Info->Counter = Counter; - for (unsigned pi = 0; pi != Info->NumPreds; ++pi) { - BasicBlock *Pred = Info->Preds[pi]; - BBMapTy::value_type &BBMapBucket = BBMap->FindAndConstruct(Pred); - if (!BBMapBucket.second) { - Value *PredVal = AvailableVals.lookup(Pred); - BBMapBucket.second = new (*Allocator) BBInfo(Pred, PredVal, Allocator); - } - BBInfo *PredInfo = BBMapBucket.second; - BasicBlock *DefBB = 0; - if (!PredInfo->AvailableVal) { - if (PredInfo->Counter != Counter) - FindPHIPlacement(Pred, PredInfo, Changed, Counter); - - // Ignore back edges where the value is not yet known. - if (!PredInfo->DefBB) - continue; + // Okay, the value isn't in the map and we just inserted a null in the entry + // to indicate that we're processing the block. Since we have no idea what + // value is in this block, we have to recurse through our predecessors. + // + // While we're walking our predecessors, we keep track of them in a vector, + // then insert a PHI node in the end if we actually need one. We could use a + // smallvector here, but that would take a lot of stack space for every level + // of the recursion, just use IncomingPredInfo as an explicit stack. + IncomingPredInfoTy &IncomingPredInfo = getIncomingPredInfo(IPI); + unsigned FirstPredInfoEntry = IncomingPredInfo.size(); + + // As we're walking the predecessors, keep track of whether they are all + // producing the same value. If so, this value will capture it, if not, it + // will get reset to null. We distinguish the no-predecessor case explicitly + // below. + TrackingVH<Value> ExistingValue; + + // We can get our predecessor info by walking the pred_iterator list, but it + // is relatively slow. If we already have PHI nodes in this block, walk one + // of them to get the predecessor list instead. + if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin())) { + for (unsigned i = 0, e = SomePhi->getNumIncomingValues(); i != e; ++i) { + BasicBlock *PredBB = SomePhi->getIncomingBlock(i); + Value *PredVal = GetValueAtEndOfBlockInternal(PredBB); + IncomingPredInfo.push_back(std::make_pair(PredBB, PredVal)); + + // Set ExistingValue to singular value from all predecessors so far. + if (i == 0) + ExistingValue = PredVal; + else if (PredVal != ExistingValue) + ExistingValue = 0; } - DefBB = PredInfo->DefBB; + } else { + bool isFirstPred = true; + for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) { + BasicBlock *PredBB = *PI; + Value *PredVal = GetValueAtEndOfBlockInternal(PredBB); + IncomingPredInfo.push_back(std::make_pair(PredBB, PredVal)); - if (!SamePredDefBB) - SamePredDefBB = DefBB; - else if (DefBB != SamePredDefBB) - BBNeedsPHI = true; + // Set ExistingValue to singular value from all predecessors so far. + if (isFirstPred) { + ExistingValue = PredVal; + isFirstPred = false; + } else if (PredVal != ExistingValue) + ExistingValue = 0; + } } - BasicBlock *NewDefBB = (BBNeedsPHI ? BB : SamePredDefBB); - if (Info->DefBB != NewDefBB) { - Changed = true; - Info->DefBB = NewDefBB; - } -} + // If there are no predecessors, then we must have found an unreachable block + // just return 'undef'. Since there are no predecessors, InsertRes must not + // be invalidated. + if (IncomingPredInfo.size() == FirstPredInfoEntry) + return InsertRes.first->second = UndefValue::get(PrototypeValue->getType()); + + /// Look up BB's entry in AvailableVals. 'InsertRes' may be invalidated. If + /// this block is involved in a loop, a no-entry PHI node will have been + /// inserted as InsertedVal. Otherwise, we'll still have the null we inserted + /// above. + TrackingVH<Value> &InsertedVal = AvailableVals[BB]; + + // If the predecessor values are not all the same, then check to see if there + // is an existing PHI that can be used. + if (!ExistingValue) + ExistingValue = GetExistingPHI(BB, + IncomingPredInfo.begin()+FirstPredInfoEntry, + IncomingPredInfo.end()); + + // If there is an existing value we can use, then we don't need to insert a + // PHI. This is the simple and common case. + if (ExistingValue) { + // If a PHI node got inserted, replace it with the existing value and delete + // it. + if (InsertedVal) { + PHINode *OldVal = cast<PHINode>(InsertedVal); + // Be careful about dead loops. These RAUW's also update InsertedVal. + if (InsertedVal != ExistingValue) + OldVal->replaceAllUsesWith(ExistingValue); + else + OldVal->replaceAllUsesWith(UndefValue::get(InsertedVal->getType())); + OldVal->eraseFromParent(); + } else { + InsertedVal = ExistingValue; + } -/// FindAvailableVal - If this block requires a PHI, first check if an existing -/// PHI matches the PHI placement and reaching definitions computed earlier, -/// and if not, create a new PHI. Visit all the block's predecessors to -/// calculate the available value for each one and fill in the incoming values -/// for a new PHI. -void SSAUpdater::FindAvailableVal(BasicBlock *BB, BBInfo *Info, - unsigned Counter) { - if (Info->AvailableVal || Info->Counter == Counter) - return; + // Either path through the 'if' should have set InsertedVal -> ExistingVal. + assert((InsertedVal == ExistingValue || isa<UndefValue>(InsertedVal)) && + "RAUW didn't change InsertedVal to be ExistingValue"); - AvailableValsTy &AvailableVals = getAvailableVals(AV); - BBMapTy *BBMap = getBBMap(BM); - - // Check if there needs to be a PHI in BB. - PHINode *NewPHI = 0; - if (Info->DefBB == BB) { - // Look for an existing PHI. - FindExistingPHI(BB); - if (!Info->AvailableVal) { - NewPHI = PHINode::Create(PrototypeValue->getType(), - PrototypeValue->getName(), &BB->front()); - NewPHI->reserveOperandSpace(Info->NumPreds); - Info->AvailableVal = NewPHI; - AvailableVals[BB] = NewPHI; - } + // Drop the entries we added in IncomingPredInfo to restore the stack. + IncomingPredInfo.erase(IncomingPredInfo.begin()+FirstPredInfoEntry, + IncomingPredInfo.end()); + return ExistingValue; } - // Iterate through the block's predecessors. - Info->Counter = Counter; - for (unsigned pi = 0; pi != Info->NumPreds; ++pi) { - BasicBlock *Pred = Info->Preds[pi]; - BBInfo *PredInfo = (*BBMap)[Pred]; - FindAvailableVal(Pred, PredInfo, Counter); - if (NewPHI) { - // Skip to the nearest preceding definition. - if (PredInfo->DefBB != Pred) - PredInfo = (*BBMap)[PredInfo->DefBB]; - NewPHI->addIncoming(PredInfo->AvailableVal, Pred); - } else if (!Info->AvailableVal) - Info->AvailableVal = PredInfo->AvailableVal; - } + // Otherwise, we do need a PHI: insert one now if we don't already have one. + if (InsertedVal == 0) + InsertedVal = PHINode::Create(PrototypeValue->getType(), + PrototypeValue->getName(), &BB->front()); - if (NewPHI) { - DEBUG(dbgs() << " Inserted PHI: " << *NewPHI << "\n"); + PHINode *InsertedPHI = cast<PHINode>(InsertedVal); + InsertedPHI->reserveOperandSpace(IncomingPredInfo.size()-FirstPredInfoEntry); - // If the client wants to know about all new instructions, tell it. - if (InsertedPHIs) InsertedPHIs->push_back(NewPHI); - } -} + // Fill in all the predecessors of the PHI. + for (IncomingPredInfoTy::iterator I = + IncomingPredInfo.begin()+FirstPredInfoEntry, + E = IncomingPredInfo.end(); I != E; ++I) + InsertedPHI->addIncoming(I->second, I->first); -/// FindExistingPHI - Look through the PHI nodes in a block to see if any of -/// them match what is needed. -void SSAUpdater::FindExistingPHI(BasicBlock *BB) { - PHINode *SomePHI; - for (BasicBlock::iterator It = BB->begin(); - (SomePHI = dyn_cast<PHINode>(It)); ++It) { - if (CheckIfPHIMatches(SomePHI)) { - RecordMatchingPHI(SomePHI); - break; - } - ClearPHITags(SomePHI); - } -} + // Drop the entries we added in IncomingPredInfo to restore the stack. + IncomingPredInfo.erase(IncomingPredInfo.begin()+FirstPredInfoEntry, + IncomingPredInfo.end()); -/// CheckIfPHIMatches - Check if a PHI node matches the placement and values -/// in the BBMap. -bool SSAUpdater::CheckIfPHIMatches(PHINode *PHI) { - BBMapTy *BBMap = getBBMap(BM); - 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 true; -} + // See if the PHI node can be merged to a single value. This can happen in + // loop cases when we get a PHI of itself and one other value. + if (Value *ConstVal = InsertedPHI->hasConstantValue()) { + InsertedPHI->replaceAllUsesWith(ConstVal); + InsertedPHI->eraseFromParent(); + InsertedVal = ConstVal; + } else { + DEBUG(dbgs() << " Inserted PHI: " << *InsertedPHI << "\n"); -/// RecordMatchingPHI - For a PHI node that matches, record it and its input -/// PHIs in both the BBMap and the AvailableVals mapping. -void SSAUpdater::RecordMatchingPHI(PHINode *PHI) { - BBMapTy *BBMap = getBBMap(BM); - AvailableValsTy &AvailableVals = getAvailableVals(AV); - SmallVector<PHINode*, 20> WorkList; - WorkList.push_back(PHI); - - // Record this PHI. - BasicBlock *BB = PHI->getParent(); - AvailableVals[BB] = PHI; - (*BBMap)[BB]->AvailableVal = 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) { - PHINode *IncomingPHIVal = dyn_cast<PHINode>(PHI->getIncomingValue(i)); - if (!IncomingPHIVal) continue; - BB = IncomingPHIVal->getParent(); - BBInfo *Info = (*BBMap)[BB]; - if (!Info || Info->AvailableVal) - continue; - - // Record the PHI and add it to the worklist. - AvailableVals[BB] = IncomingPHIVal; - Info->AvailableVal = IncomingPHIVal; - WorkList.push_back(IncomingPHIVal); - } + // If the client wants to know about all new instructions, tell it. + if (InsertedPHIs) InsertedPHIs->push_back(InsertedPHI); } -} -/// ClearPHITags - When one of the existing PHI nodes fails to match, clear -/// the PHITag values that were stored in the BBMap when checking to see if -/// it matched. -void SSAUpdater::ClearPHITags(PHINode *PHI) { - BBMapTy *BBMap = getBBMap(BM); - SmallVector<PHINode*, 20> WorkList; - WorkList.push_back(PHI); - - // Clear the tag for this PHI. - (*BBMap)[PHI->getParent()]->PHITag = 0; - - 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) { - PHINode *IncomingPHIVal = dyn_cast<PHINode>(PHI->getIncomingValue(i)); - if (!IncomingPHIVal) continue; - BasicBlock *BB = IncomingPHIVal->getParent(); - BBInfo *Info = (*BBMap)[BB]; - if (!Info || Info->AvailableVal || !Info->PHITag) - continue; - - // Clear the tag and add the PHI to the worklist. - Info->PHITag = 0; - WorkList.push_back(IncomingPHIVal); - } - } + return InsertedVal; } |