if (SingularValue != 0)
return SingularValue;
- // Otherwise, we do need a PHI: insert one now.
+ // 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) {
+ // Scan this phi to see if it is what we need.
+ bool Equal = true;
+ for (unsigned i = 0, e = SomePHI->getNumIncomingValues(); i != e; ++i)
+ if (ValueMapping[SomePHI->getIncomingBlock(i)] !=
+ SomePHI->getIncomingValue(i)) {
+ Equal = false;
+ break;
+ }
+
+ if (Equal)
+ return SomePHI;
+ }
+ }
+
+ // Ok, we have no way out, insert a new one now.
PHINode *InsertedPHI = PHINode::Create(PrototypeValue->getType(),
PrototypeValue->getName(),
&BB->front());
// If the client wants to know about all new instructions, tell it.
if (InsertedPHIs) InsertedPHIs->push_back(InsertedPHI);
- DEBUG(errs() << " Inserted PHI: " << *InsertedPHI << "\n");
+ DEBUG(dbgs() << " Inserted PHI: " << *InsertedPHI << "\n");
return InsertedPHI;
}
/// which use their value in the corresponding predecessor.
void SSAUpdater::RewriteUse(Use &U) {
Instruction *User = cast<Instruction>(U.getUser());
- BasicBlock *UseBB = User->getParent();
+
+ Value *V;
if (PHINode *UserPN = dyn_cast<PHINode>(User))
- UseBB = UserPN->getIncomingBlock(U);
+ V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U));
+ else
+ V = GetValueInMiddleOfBlock(User->getParent());
- U.set(GetValueInMiddleOfBlock(UseBB));
+ U.set(V);
}
// Query AvailableVals by doing an insertion of null.
std::pair<AvailableValsTy::iterator, bool> InsertRes =
- AvailableVals.insert(std::make_pair(BB, WeakVH()));
+ AvailableVals.insert(std::make_pair(BB, TrackingVH<Value>()));
// Handle the case when the insertion fails because we have already seen BB.
if (!InsertRes.second) {
// 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());
+ PHINode::Create(PrototypeValue->getType(), PrototypeValue->getName(),
+ &BB->front());
}
// Okay, the value isn't in the map and we just inserted a null in the entry
InsertedVal = SingularValue;
}
+ // Either path through the 'if' should have set insertedVal -> SingularVal.
+ assert((InsertedVal == SingularValue || isa<UndefValue>(InsertedVal)) &&
+ "RAUW didn't change InsertedVal to be SingularVal");
+
// Drop the entries we added in IncomingPredInfo to restore the stack.
IncomingPredInfo.erase(IncomingPredInfo.begin()+FirstPredInfoEntry,
IncomingPredInfo.end());
- return InsertedVal;
+ return SingularValue;
}
// Otherwise, we do need a PHI: insert one now if we don't already have one.
InsertedPHI->eraseFromParent();
InsertedVal = ConstVal;
} else {
- DEBUG(errs() << " Inserted PHI: " << *InsertedPHI << "\n");
+ DEBUG(dbgs() << " Inserted PHI: " << *InsertedPHI << "\n");
// If the client wants to know about all new instructions, tell it.
if (InsertedPHIs) InsertedPHIs->push_back(InsertedPHI);