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diff --git a/contrib/llvm/lib/Transforms/Utils/SSAUpdater.cpp b/contrib/llvm/lib/Transforms/Utils/SSAUpdater.cpp
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+//===- 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.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "ssaupdater"
+#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"
+#include "llvm/Transforms/Utils/SSAUpdater.h"
+#include "llvm/Transforms/Utils/SSAUpdaterImpl.h"
+using namespace llvm;
+
+typedef DenseMap<BasicBlock*, Value*> AvailableValsTy;
+static AvailableValsTy &getAvailableVals(void *AV) {
+ return *static_cast<AvailableValsTy*>(AV);
+}
+
+SSAUpdater::SSAUpdater(SmallVectorImpl<PHINode*> *NewPHI)
+ : AV(0), PrototypeValue(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;
+}
+
+/// GetValueAtEndOfBlock - Construct SSA form, materializing a value that is
+/// live at the end of the specified block.
+Value *SSAUpdater::GetValueAtEndOfBlock(BasicBlock *BB) {
+ Value *Res = GetValueAtEndOfBlockInternal(BB);
+ 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: 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;
+ }
+ }
+
+ // 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);
+}
+
+/// PHIiter - Iterator for PHI operands. This is used for the PHI_iterator
+/// in the SSAUpdaterImpl template.
+namespace {
+ class PHIiter {
+ private:
+ PHINode *PHI;
+ unsigned idx;
+
+ public:
+ explicit PHIiter(PHINode *P) // begin iterator
+ : PHI(P), idx(0) {}
+ PHIiter(PHINode *P, bool) // end iterator
+ : PHI(P), idx(PHI->getNumIncomingValues()) {}
+
+ PHIiter &operator++() { ++idx; return *this; }
+ bool operator==(const PHIiter& x) const { return idx == x.idx; }
+ bool operator!=(const PHIiter& x) const { return !operator==(x); }
+ Value *getIncomingValue() { return PHI->getIncomingValue(idx); }
+ BasicBlock *getIncomingBlock() { return PHI->getIncomingBlock(idx); }
+ };
+}
+
+/// SSAUpdaterTraits<SSAUpdater> - Traits for the SSAUpdaterImpl template,
+/// specialized for SSAUpdater.
+namespace llvm {
+template<>
+class SSAUpdaterTraits<SSAUpdater> {
+public:
+ typedef BasicBlock BlkT;
+ typedef Value *ValT;
+ typedef PHINode PhiT;
+
+ typedef succ_iterator BlkSucc_iterator;
+ static BlkSucc_iterator BlkSucc_begin(BlkT *BB) { return succ_begin(BB); }
+ static BlkSucc_iterator BlkSucc_end(BlkT *BB) { return succ_end(BB); }
+
+ typedef PHIiter PHI_iterator;
+ static inline PHI_iterator PHI_begin(PhiT *PHI) { return PHI_iterator(PHI); }
+ static inline PHI_iterator PHI_end(PhiT *PHI) {
+ return PHI_iterator(PHI, true);
+ }
+
+ /// FindPredecessorBlocks - Put the predecessors of Info->BB into the Preds
+ /// vector, set Info->NumPreds, and allocate space in Info->Preds.
+ static void FindPredecessorBlocks(BasicBlock *BB,
+ SmallVectorImpl<BasicBlock*> *Preds) {
+ // 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 PI = 0, E = SomePhi->getNumIncomingValues(); PI != E; ++PI)
+ Preds->push_back(SomePhi->getIncomingBlock(PI));
+ } else {
+ for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
+ Preds->push_back(*PI);
+ }
+ }
+
+ /// GetUndefVal - Get an undefined value of the same type as the value
+ /// being handled.
+ static Value *GetUndefVal(BasicBlock *BB, SSAUpdater *Updater) {
+ return UndefValue::get(Updater->PrototypeValue->getType());
+ }
+
+ /// CreateEmptyPHI - Create a new PHI instruction in the specified block.
+ /// Reserve space for the operands but do not fill them in yet.
+ static Value *CreateEmptyPHI(BasicBlock *BB, unsigned NumPreds,
+ SSAUpdater *Updater) {
+ PHINode *PHI = PHINode::Create(Updater->PrototypeValue->getType(),
+ Updater->PrototypeValue->getName(),
+ &BB->front());
+ PHI->reserveOperandSpace(NumPreds);
+ return PHI;
+ }
+
+ /// AddPHIOperand - Add the specified value as an operand of the PHI for
+ /// the specified predecessor block.
+ static void AddPHIOperand(PHINode *PHI, Value *Val, BasicBlock *Pred) {
+ PHI->addIncoming(Val, Pred);
+ }
+
+ /// InstrIsPHI - Check if an instruction is a PHI.
+ ///
+ static PHINode *InstrIsPHI(Instruction *I) {
+ return dyn_cast<PHINode>(I);
+ }
+
+ /// ValueIsPHI - Check if a value is a PHI.
+ ///
+ static PHINode *ValueIsPHI(Value *Val, SSAUpdater *Updater) {
+ return dyn_cast<PHINode>(Val);
+ }
+
+ /// ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source
+ /// operands, i.e., it was just added.
+ static PHINode *ValueIsNewPHI(Value *Val, SSAUpdater *Updater) {
+ PHINode *PHI = ValueIsPHI(Val, Updater);
+ if (PHI && PHI->getNumIncomingValues() == 0)
+ return PHI;
+ return 0;
+ }
+
+ /// GetPHIValue - For the specified PHI instruction, return the value
+ /// that it defines.
+ static Value *GetPHIValue(PHINode *PHI) {
+ return PHI;
+ }
+};
+
+} // End llvm namespace
+
+/// 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;
+
+ SSAUpdaterImpl<SSAUpdater> Impl(this, &AvailableVals, InsertedPHIs);
+ return Impl.GetValue(BB);
+}
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