mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-10-17 03:26:03 +00:00
e8b64281ce
blow out the stack for really big functions. Start by fixing an easy case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100126 91177308-0d34-0410-b5e6-96231b3b80d8
518 lines
18 KiB
C++
518 lines
18 KiB
C++
//===- SSAUpdater.cpp - Unstructured SSA Update Tool ----------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the SSAUpdater class.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#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/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*, Value*> AvailableValsTy;
|
|
static AvailableValsTy &getAvailableVals(void *AV) {
|
|
return *static_cast<AvailableValsTy*>(AV);
|
|
}
|
|
|
|
static BBMapTy *getBBMap(void *BM) {
|
|
return static_cast<BBMapTy*>(BM);
|
|
}
|
|
|
|
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) {}
|
|
|
|
SSAUpdater::~SSAUpdater() {
|
|
delete &getAvailableVals(AV);
|
|
}
|
|
|
|
/// Initialize - Reset this object to get ready for a new set of SSA
|
|
/// updates. ProtoValue is the value used to name PHI nodes.
|
|
void SSAUpdater::Initialize(Value *ProtoValue) {
|
|
if (AV == 0)
|
|
AV = new AvailableValsTy();
|
|
else
|
|
getAvailableVals(AV).clear();
|
|
PrototypeValue = ProtoValue;
|
|
}
|
|
|
|
/// HasValueForBlock - Return true if the SSAUpdater already has a value for
|
|
/// the specified block.
|
|
bool SSAUpdater::HasValueForBlock(BasicBlock *BB) const {
|
|
return getAvailableVals(AV).count(BB);
|
|
}
|
|
|
|
/// AddAvailableValue - Indicate that a rewritten value is available in the
|
|
/// specified block with the specified value.
|
|
void SSAUpdater::AddAvailableValue(BasicBlock *BB, Value *V) {
|
|
assert(PrototypeValue != 0 && "Need to initialize SSAUpdater");
|
|
assert(PrototypeValue->getType() == V->getType() &&
|
|
"All rewritten values must have the same type");
|
|
getAvailableVals(AV)[BB] = V;
|
|
}
|
|
|
|
/// IsEquivalentPHI - Check if PHI has the same incoming value as specified
|
|
/// in ValueMapping for each predecessor block.
|
|
static bool IsEquivalentPHI(PHINode *PHI,
|
|
DenseMap<BasicBlock*, Value*> &ValueMapping) {
|
|
unsigned PHINumValues = PHI->getNumIncomingValues();
|
|
if (PHINumValues != ValueMapping.size())
|
|
return false;
|
|
|
|
// Scan the phi to see if it matches.
|
|
for (unsigned i = 0, e = PHINumValues; i != e; ++i)
|
|
if (ValueMapping[PHI->getIncomingBlock(i)] !=
|
|
PHI->getIncomingValue(i)) {
|
|
return false;
|
|
}
|
|
|
|
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");
|
|
Value *Res = GetValueAtEndOfBlockInternal(BB);
|
|
assert(BM == 0 && BPA == 0 && "Unexpected Internal State");
|
|
return Res;
|
|
}
|
|
|
|
/// GetValueInMiddleOfBlock - Construct SSA form, materializing a value that
|
|
/// is live in the middle of the specified block.
|
|
///
|
|
/// GetValueInMiddleOfBlock is the same as GetValueAtEndOfBlock except in one
|
|
/// important case: if there is a definition of the rewritten value after the
|
|
/// 'use' in BB. Consider code like this:
|
|
///
|
|
/// X1 = ...
|
|
/// SomeBB:
|
|
/// use(X)
|
|
/// X2 = ...
|
|
/// br Cond, SomeBB, OutBB
|
|
///
|
|
/// In this case, there are two values (X1 and X2) added to the AvailableVals
|
|
/// set by the client of the rewriter, and those values are both live out of
|
|
/// their respective blocks. However, the use of X happens in the *middle* of
|
|
/// a block. Because of this, we need to insert a new PHI node in SomeBB to
|
|
/// merge the appropriate values, and this value isn't live out of the block.
|
|
///
|
|
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))
|
|
return GetValueAtEndOfBlock(BB);
|
|
|
|
// Otherwise, we have the hard case. Get the live-in values for each
|
|
// predecessor.
|
|
SmallVector<std::pair<BasicBlock*, Value*>, 8> PredValues;
|
|
Value *SingularValue = 0;
|
|
|
|
// 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 = GetValueAtEndOfBlock(PredBB);
|
|
PredValues.push_back(std::make_pair(PredBB, PredVal));
|
|
|
|
// Compute SingularValue.
|
|
if (i == 0)
|
|
SingularValue = PredVal;
|
|
else if (PredVal != SingularValue)
|
|
SingularValue = 0;
|
|
}
|
|
} else {
|
|
bool isFirstPred = true;
|
|
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
|
|
BasicBlock *PredBB = *PI;
|
|
Value *PredVal = GetValueAtEndOfBlock(PredBB);
|
|
PredValues.push_back(std::make_pair(PredBB, PredVal));
|
|
|
|
// Compute SingularValue.
|
|
if (isFirstPred) {
|
|
SingularValue = PredVal;
|
|
isFirstPred = false;
|
|
} else if (PredVal != SingularValue)
|
|
SingularValue = 0;
|
|
}
|
|
}
|
|
|
|
// If there are no predecessors, just return undef.
|
|
if (PredValues.empty())
|
|
return UndefValue::get(PrototypeValue->getType());
|
|
|
|
// Otherwise, if all the merged values are the same, just use it.
|
|
if (SingularValue != 0)
|
|
return SingularValue;
|
|
|
|
// 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(),
|
|
PrototypeValue->getName(),
|
|
&BB->front());
|
|
InsertedPHI->reserveOperandSpace(PredValues.size());
|
|
|
|
// Fill in all the predecessors of the PHI.
|
|
for (unsigned i = 0, e = PredValues.size(); i != e; ++i)
|
|
InsertedPHI->addIncoming(PredValues[i].second, PredValues[i].first);
|
|
|
|
// 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->eraseFromParent();
|
|
return ConstVal;
|
|
}
|
|
|
|
// If the client wants to know about all new instructions, tell it.
|
|
if (InsertedPHIs) InsertedPHIs->push_back(InsertedPHI);
|
|
|
|
DEBUG(dbgs() << " Inserted PHI: " << *InsertedPHI << "\n");
|
|
return InsertedPHI;
|
|
}
|
|
|
|
/// RewriteUse - Rewrite a use of the symbolic value. This handles PHI nodes,
|
|
/// 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));
|
|
else
|
|
V = GetValueInMiddleOfBlock(User->getParent());
|
|
|
|
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.
|
|
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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
DefBB = PredInfo->DefBB;
|
|
|
|
if (!SamePredDefBB)
|
|
SamePredDefBB = DefBB;
|
|
else if (DefBB != SamePredDefBB)
|
|
BBNeedsPHI = true;
|
|
}
|
|
|
|
BasicBlock *NewDefBB = (BBNeedsPHI ? BB : SamePredDefBB);
|
|
if (Info->DefBB != NewDefBB) {
|
|
Changed = true;
|
|
Info->DefBB = NewDefBB;
|
|
}
|
|
}
|
|
|
|
/// 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;
|
|
|
|
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, Info);
|
|
if (!Info->AvailableVal) {
|
|
NewPHI = PHINode::Create(PrototypeValue->getType(),
|
|
PrototypeValue->getName(), &BB->front());
|
|
NewPHI->reserveOperandSpace(Info->NumPreds);
|
|
Info->AvailableVal = NewPHI;
|
|
AvailableVals[BB] = NewPHI;
|
|
}
|
|
}
|
|
|
|
// 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;
|
|
}
|
|
|
|
if (NewPHI) {
|
|
DEBUG(dbgs() << " Inserted PHI: " << *NewPHI << "\n");
|
|
|
|
// If the client wants to know about all new instructions, tell it.
|
|
if (InsertedPHIs) InsertedPHIs->push_back(NewPHI);
|
|
}
|
|
}
|
|
|
|
/// 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) {
|
|
PHINode *SomePHI;
|
|
for (BasicBlock::iterator It = BB->begin();
|
|
(SomePHI = dyn_cast<PHINode>(It)); ++It) {
|
|
if (CheckIfPHIMatches(BB, Info, SomePHI)) {
|
|
RecordMatchingPHI(BB, Info, SomePHI);
|
|
break;
|
|
}
|
|
ClearPHITags(SomePHI);
|
|
}
|
|
}
|
|
|
|
/// 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.
|
|
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;
|
|
}
|
|
}
|
|
return IsMatch;
|
|
}
|
|
|
|
/// RecordMatchingPHI - For a PHI node that matches, record it in both the
|
|
/// BBMap and the AvailableVals mapping. Recursively record its input PHIs
|
|
/// as well.
|
|
void SSAUpdater::RecordMatchingPHI(BasicBlock *BB, BBInfo *Info, PHINode *PHI) {
|
|
if (!Info || Info->AvailableVal)
|
|
return;
|
|
|
|
// Record the PHI.
|
|
AvailableValsTy &AvailableVals = getAvailableVals(AV);
|
|
AvailableVals[BB] = PHI;
|
|
Info->AvailableVal = PHI;
|
|
|
|
// Iterate through the predecessors.
|
|
BBMapTy *BBMap = getBBMap(BM);
|
|
for (unsigned i = 0, e = PHI->getNumIncomingValues(); i != e; ++i) {
|
|
PHINode *PHIVal = dyn_cast<PHINode>(PHI->getIncomingValue(i));
|
|
if (!PHIVal) continue;
|
|
BasicBlock *Pred = PHIVal->getParent();
|
|
RecordMatchingPHI(Pred, (*BBMap)[Pred], PHIVal);
|
|
}
|
|
}
|
|
|
|
/// 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);
|
|
|
|
while (!WorkList.empty()) {
|
|
PHI = WorkList.pop_back_val();
|
|
BasicBlock *BB = PHI->getParent();
|
|
BBInfo *Info = (*BBMap)[BB];
|
|
if (!Info || Info->AvailableVal || !Info->PHITag)
|
|
continue;
|
|
|
|
// Clear the tag.
|
|
Info->PHITag = 0;
|
|
|
|
// Iterate through the PHI's incoming values.
|
|
for (unsigned i = 0, e = PHI->getNumIncomingValues(); i != e; ++i) {
|
|
PHINode *IncomingVal = dyn_cast<PHINode>(PHI->getIncomingValue(i));
|
|
if (!IncomingVal) continue;
|
|
WorkList.push_back(IncomingVal);
|
|
}
|
|
}
|
|
}
|