Update to LLVM 3.5a.

Change-Id: Ifadecab779f128e62e430c2b4f6ddd84953ed617

1 files changed, 662 insertions, 0 deletions

diff --git a/lib/Transforms/Scalar/Scalarizer.cpp b/lib/Transforms/Scalar/Scalarizer.cpp
new file mode 100644
index 0000000..006375c
--- /dev/null
+++ b/lib/Transforms/Scalar/Scalarizer.cpp
@@ -0,0 +1,662 @@
+//===--- Scalarizer.cpp - Scalarize vector operations ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass converts vector operations into scalar operations, in order
+// to expose optimization opportunities on the individual scalar operations.
+// It is mainly intended for targets that do not have vector units, but it
+// may also be useful for revectorizing code to different vector widths.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "scalarizer"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InstVisitor.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+
+using namespace llvm;
+
+namespace {
+// Used to store the scattered form of a vector.
+typedef SmallVector<Value *, 8> ValueVector;
+
+// Used to map a vector Value to its scattered form.  We use std::map
+// because we want iterators to persist across insertion and because the
+// values are relatively large.
+typedef std::map<Value *, ValueVector> ScatterMap;
+
+// Lists Instructions that have been replaced with scalar implementations,
+// along with a pointer to their scattered forms.
+typedef SmallVector<std::pair<Instruction *, ValueVector *>, 16> GatherList;
+
+// Provides a very limited vector-like interface for lazily accessing one
+// component of a scattered vector or vector pointer.
+class Scatterer {
+public:
+  Scatterer() {}
+
+  // Scatter V into Size components.  If new instructions are needed,
+  // insert them before BBI in BB.  If Cache is nonnull, use it to cache
+  // the results.
+  Scatterer(BasicBlock *bb, BasicBlock::iterator bbi, Value *v,
+            ValueVector *cachePtr = 0);
+
+  // Return component I, creating a new Value for it if necessary.
+  Value *operator[](unsigned I);
+
+  // Return the number of components.
+  unsigned size() const { return Size; }
+
+private:
+  BasicBlock *BB;
+  BasicBlock::iterator BBI;
+  Value *V;
+  ValueVector *CachePtr;
+  PointerType *PtrTy;
+  ValueVector Tmp;
+  unsigned Size;
+};
+
+// FCmpSpliiter(FCI)(Builder, X, Y, Name) uses Builder to create an FCmp
+// called Name that compares X and Y in the same way as FCI.
+struct FCmpSplitter {
+  FCmpSplitter(FCmpInst &fci) : FCI(fci) {}
+  Value *operator()(IRBuilder<> &Builder, Value *Op0, Value *Op1,
+                    const Twine &Name) const {
+    return Builder.CreateFCmp(FCI.getPredicate(), Op0, Op1, Name);
+  }
+  FCmpInst &FCI;
+};
+
+// ICmpSpliiter(ICI)(Builder, X, Y, Name) uses Builder to create an ICmp
+// called Name that compares X and Y in the same way as ICI.
+struct ICmpSplitter {
+  ICmpSplitter(ICmpInst &ici) : ICI(ici) {}
+  Value *operator()(IRBuilder<> &Builder, Value *Op0, Value *Op1,
+                    const Twine &Name) const {
+    return Builder.CreateICmp(ICI.getPredicate(), Op0, Op1, Name);
+  }
+  ICmpInst &ICI;
+};
+
+// BinarySpliiter(BO)(Builder, X, Y, Name) uses Builder to create
+// a binary operator like BO called Name with operands X and Y.
+struct BinarySplitter {
+  BinarySplitter(BinaryOperator &bo) : BO(bo) {}
+  Value *operator()(IRBuilder<> &Builder, Value *Op0, Value *Op1,
+                    const Twine &Name) const {
+    return Builder.CreateBinOp(BO.getOpcode(), Op0, Op1, Name);
+  }
+  BinaryOperator &BO;
+};
+
+// Information about a load or store that we're scalarizing.
+struct VectorLayout {
+  VectorLayout() : VecTy(0), ElemTy(0), VecAlign(0), ElemSize(0) {}
+
+  // Return the alignment of element I.
+  uint64_t getElemAlign(unsigned I) {
+    return MinAlign(VecAlign, I * ElemSize);
+  }
+
+  // The type of the vector.
+  VectorType *VecTy;
+
+  // The type of each element.
+  Type *ElemTy;
+
+  // The alignment of the vector.
+  uint64_t VecAlign;
+
+  // The size of each element.
+  uint64_t ElemSize;
+};
+
+class Scalarizer : public FunctionPass,
+                   public InstVisitor<Scalarizer, bool> {
+public:
+  static char ID;
+
+  Scalarizer() :
+    FunctionPass(ID) {
+    initializeScalarizerPass(*PassRegistry::getPassRegistry());
+  }
+
+  bool doInitialization(Module &M) override;
+  bool runOnFunction(Function &F) override;
+
+  // InstVisitor methods.  They return true if the instruction was scalarized,
+  // false if nothing changed.
+  bool visitInstruction(Instruction &) { return false; }
+  bool visitSelectInst(SelectInst &SI);
+  bool visitICmpInst(ICmpInst &);
+  bool visitFCmpInst(FCmpInst &);
+  bool visitBinaryOperator(BinaryOperator &);
+  bool visitGetElementPtrInst(GetElementPtrInst &);
+  bool visitCastInst(CastInst &);
+  bool visitBitCastInst(BitCastInst &);
+  bool visitShuffleVectorInst(ShuffleVectorInst &);
+  bool visitPHINode(PHINode &);
+  bool visitLoadInst(LoadInst &);
+  bool visitStoreInst(StoreInst &);
+
+private:
+  Scatterer scatter(Instruction *, Value *);
+  void gather(Instruction *, const ValueVector &);
+  bool canTransferMetadata(unsigned Kind);
+  void transferMetadata(Instruction *, const ValueVector &);
+  bool getVectorLayout(Type *, unsigned, VectorLayout &);
+  bool finish();
+
+  template<typename T> bool splitBinary(Instruction &, const T &);
+
+  ScatterMap Scattered;
+  GatherList Gathered;
+  unsigned ParallelLoopAccessMDKind;
+  const DataLayout *DL;
+};
+
+char Scalarizer::ID = 0;
+} // end anonymous namespace
+
+// This is disabled by default because having separate loads and stores makes
+// it more likely that the -combiner-alias-analysis limits will be reached.
+static cl::opt<bool> ScalarizeLoadStore
+  ("scalarize-load-store", cl::Hidden, cl::init(false),
+   cl::desc("Allow the scalarizer pass to scalarize loads and store"));
+
+INITIALIZE_PASS(Scalarizer, "scalarizer", "Scalarize vector operations",
+                false, false)
+
+Scatterer::Scatterer(BasicBlock *bb, BasicBlock::iterator bbi, Value *v,
+                     ValueVector *cachePtr)
+  : BB(bb), BBI(bbi), V(v), CachePtr(cachePtr) {
+  Type *Ty = V->getType();
+  PtrTy = dyn_cast<PointerType>(Ty);
+  if (PtrTy)
+    Ty = PtrTy->getElementType();
+  Size = Ty->getVectorNumElements();
+  if (!CachePtr)
+    Tmp.resize(Size, 0);
+  else if (CachePtr->empty())
+    CachePtr->resize(Size, 0);
+  else
+    assert(Size == CachePtr->size() && "Inconsistent vector sizes");
+}
+
+// Return component I, creating a new Value for it if necessary.
+Value *Scatterer::operator[](unsigned I) {
+  ValueVector &CV = (CachePtr ? *CachePtr : Tmp);
+  // Try to reuse a previous value.
+  if (CV[I])
+    return CV[I];
+  IRBuilder<> Builder(BB, BBI);
+  if (PtrTy) {
+    if (!CV[0]) {
+      Type *Ty =
+        PointerType::get(PtrTy->getElementType()->getVectorElementType(),
+                         PtrTy->getAddressSpace());
+      CV[0] = Builder.CreateBitCast(V, Ty, V->getName() + ".i0");
+    }
+    if (I != 0)
+      CV[I] = Builder.CreateConstGEP1_32(CV[0], I,
+                                         V->getName() + ".i" + Twine(I));
+  } else {
+    // Search through a chain of InsertElementInsts looking for element I.
+    // Record other elements in the cache.  The new V is still suitable
+    // for all uncached indices.
+    for (;;) {
+      InsertElementInst *Insert = dyn_cast<InsertElementInst>(V);
+      if (!Insert)
+        break;
+      ConstantInt *Idx = dyn_cast<ConstantInt>(Insert->getOperand(2));
+      if (!Idx)
+        break;
+      unsigned J = Idx->getZExtValue();
+      CV[J] = Insert->getOperand(1);
+      V = Insert->getOperand(0);
+      if (I == J)
+        return CV[J];
+    }
+    CV[I] = Builder.CreateExtractElement(V, Builder.getInt32(I),
+                                         V->getName() + ".i" + Twine(I));
+  }
+  return CV[I];
+}
+
+bool Scalarizer::doInitialization(Module &M) {
+  ParallelLoopAccessMDKind =
+    M.getContext().getMDKindID("llvm.mem.parallel_loop_access");
+  return false;
+}
+
+bool Scalarizer::runOnFunction(Function &F) {
+  DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
+  DL = DLP ? &DLP->getDataLayout() : 0;
+  for (Function::iterator BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) {
+    BasicBlock *BB = BBI;
+    for (BasicBlock::iterator II = BB->begin(), IE = BB->end(); II != IE;) {
+      Instruction *I = II;
+      bool Done = visit(I);
+      ++II;
+      if (Done && I->getType()->isVoidTy())
+        I->eraseFromParent();
+    }
+  }
+  return finish();
+}
+
+// Return a scattered form of V that can be accessed by Point.  V must be a
+// vector or a pointer to a vector.
+Scatterer Scalarizer::scatter(Instruction *Point, Value *V) {
+  if (Argument *VArg = dyn_cast<Argument>(V)) {
+    // Put the scattered form of arguments in the entry block,
+    // so that it can be used everywhere.
+    Function *F = VArg->getParent();
+    BasicBlock *BB = &F->getEntryBlock();
+    return Scatterer(BB, BB->begin(), V, &Scattered[V]);
+  }
+  if (Instruction *VOp = dyn_cast<Instruction>(V)) {
+    // Put the scattered form of an instruction directly after the
+    // instruction.
+    BasicBlock *BB = VOp->getParent();
+    return Scatterer(BB, std::next(BasicBlock::iterator(VOp)),
+                     V, &Scattered[V]);
+  }
+  // In the fallback case, just put the scattered before Point and
+  // keep the result local to Point.
+  return Scatterer(Point->getParent(), Point, V);
+}
+
+// Replace Op with the gathered form of the components in CV.  Defer the
+// deletion of Op and creation of the gathered form to the end of the pass,
+// so that we can avoid creating the gathered form if all uses of Op are
+// replaced with uses of CV.
+void Scalarizer::gather(Instruction *Op, const ValueVector &CV) {
+  // Since we're not deleting Op yet, stub out its operands, so that it
+  // doesn't make anything live unnecessarily.
+  for (unsigned I = 0, E = Op->getNumOperands(); I != E; ++I)
+    Op->setOperand(I, UndefValue::get(Op->getOperand(I)->getType()));
+
+  transferMetadata(Op, CV);
+
+  // If we already have a scattered form of Op (created from ExtractElements
+  // of Op itself), replace them with the new form.
+  ValueVector &SV = Scattered[Op];
+  if (!SV.empty()) {
+    for (unsigned I = 0, E = SV.size(); I != E; ++I) {
+      Instruction *Old = cast<Instruction>(SV[I]);
+      CV[I]->takeName(Old);
+      Old->replaceAllUsesWith(CV[I]);
+      Old->eraseFromParent();
+    }
+  }
+  SV = CV;
+  Gathered.push_back(GatherList::value_type(Op, &SV));
+}
+
+// Return true if it is safe to transfer the given metadata tag from
+// vector to scalar instructions.
+bool Scalarizer::canTransferMetadata(unsigned Tag) {
+  return (Tag == LLVMContext::MD_tbaa
+          || Tag == LLVMContext::MD_fpmath
+          || Tag == LLVMContext::MD_tbaa_struct
+          || Tag == LLVMContext::MD_invariant_load
+          || Tag == ParallelLoopAccessMDKind);
+}
+
+// Transfer metadata from Op to the instructions in CV if it is known
+// to be safe to do so.
+void Scalarizer::transferMetadata(Instruction *Op, const ValueVector &CV) {
+  SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
+  Op->getAllMetadataOtherThanDebugLoc(MDs);
+  for (unsigned I = 0, E = CV.size(); I != E; ++I) {
+    if (Instruction *New = dyn_cast<Instruction>(CV[I])) {
+      for (SmallVectorImpl<std::pair<unsigned, MDNode *> >::iterator
+             MI = MDs.begin(), ME = MDs.end(); MI != ME; ++MI)
+        if (canTransferMetadata(MI->first))
+          New->setMetadata(MI->first, MI->second);
+      New->setDebugLoc(Op->getDebugLoc());
+    }
+  }
+}
+
+// Try to fill in Layout from Ty, returning true on success.  Alignment is
+// the alignment of the vector, or 0 if the ABI default should be used.
+bool Scalarizer::getVectorLayout(Type *Ty, unsigned Alignment,
+                                 VectorLayout &Layout) {
+  if (!DL)
+    return false;
+
+  // Make sure we're dealing with a vector.
+  Layout.VecTy = dyn_cast<VectorType>(Ty);
+  if (!Layout.VecTy)
+    return false;
+
+  // Check that we're dealing with full-byte elements.
+  Layout.ElemTy = Layout.VecTy->getElementType();
+  if (DL->getTypeSizeInBits(Layout.ElemTy) !=
+      DL->getTypeStoreSizeInBits(Layout.ElemTy))
+    return false;
+
+  if (Alignment)
+    Layout.VecAlign = Alignment;
+  else
+    Layout.VecAlign = DL->getABITypeAlignment(Layout.VecTy);
+  Layout.ElemSize = DL->getTypeStoreSize(Layout.ElemTy);
+  return true;
+}
+
+// Scalarize two-operand instruction I, using Split(Builder, X, Y, Name)
+// to create an instruction like I with operands X and Y and name Name.
+template<typename Splitter>
+bool Scalarizer::splitBinary(Instruction &I, const Splitter &Split) {
+  VectorType *VT = dyn_cast<VectorType>(I.getType());
+  if (!VT)
+    return false;
+
+  unsigned NumElems = VT->getNumElements();
+  IRBuilder<> Builder(I.getParent(), &I);
+  Scatterer Op0 = scatter(&I, I.getOperand(0));
+  Scatterer Op1 = scatter(&I, I.getOperand(1));
+  assert(Op0.size() == NumElems && "Mismatched binary operation");
+  assert(Op1.size() == NumElems && "Mismatched binary operation");
+  ValueVector Res;
+  Res.resize(NumElems);
+  for (unsigned Elem = 0; Elem < NumElems; ++Elem)
+    Res[Elem] = Split(Builder, Op0[Elem], Op1[Elem],
+                      I.getName() + ".i" + Twine(Elem));
+  gather(&I, Res);
+  return true;
+}
+
+bool Scalarizer::visitSelectInst(SelectInst &SI) {
+  VectorType *VT = dyn_cast<VectorType>(SI.getType());
+  if (!VT)
+    return false;
+
+  unsigned NumElems = VT->getNumElements();
+  IRBuilder<> Builder(SI.getParent(), &SI);
+  Scatterer Op1 = scatter(&SI, SI.getOperand(1));
+  Scatterer Op2 = scatter(&SI, SI.getOperand(2));
+  assert(Op1.size() == NumElems && "Mismatched select");
+  assert(Op2.size() == NumElems && "Mismatched select");
+  ValueVector Res;
+  Res.resize(NumElems);
+
+  if (SI.getOperand(0)->getType()->isVectorTy()) {
+    Scatterer Op0 = scatter(&SI, SI.getOperand(0));
+    assert(Op0.size() == NumElems && "Mismatched select");
+    for (unsigned I = 0; I < NumElems; ++I)
+      Res[I] = Builder.CreateSelect(Op0[I], Op1[I], Op2[I],
+                                    SI.getName() + ".i" + Twine(I));
+  } else {
+    Value *Op0 = SI.getOperand(0);
+    for (unsigned I = 0; I < NumElems; ++I)
+      Res[I] = Builder.CreateSelect(Op0, Op1[I], Op2[I],
+                                    SI.getName() + ".i" + Twine(I));
+  }
+  gather(&SI, Res);
+  return true;
+}
+
+bool Scalarizer::visitICmpInst(ICmpInst &ICI) {
+  return splitBinary(ICI, ICmpSplitter(ICI));
+}
+
+bool Scalarizer::visitFCmpInst(FCmpInst &FCI) {
+  return splitBinary(FCI, FCmpSplitter(FCI));
+}
+
+bool Scalarizer::visitBinaryOperator(BinaryOperator &BO) {
+  return splitBinary(BO, BinarySplitter(BO));
+}
+
+bool Scalarizer::visitGetElementPtrInst(GetElementPtrInst &GEPI) {
+  VectorType *VT = dyn_cast<VectorType>(GEPI.getType());
+  if (!VT)
+    return false;
+
+  IRBuilder<> Builder(GEPI.getParent(), &GEPI);
+  unsigned NumElems = VT->getNumElements();
+  unsigned NumIndices = GEPI.getNumIndices();
+
+  Scatterer Base = scatter(&GEPI, GEPI.getOperand(0));
+
+  SmallVector<Scatterer, 8> Ops;
+  Ops.resize(NumIndices);
+  for (unsigned I = 0; I < NumIndices; ++I)
+    Ops[I] = scatter(&GEPI, GEPI.getOperand(I + 1));
+
+  ValueVector Res;
+  Res.resize(NumElems);
+  for (unsigned I = 0; I < NumElems; ++I) {
+    SmallVector<Value *, 8> Indices;
+    Indices.resize(NumIndices);
+    for (unsigned J = 0; J < NumIndices; ++J)
+      Indices[J] = Ops[J][I];
+    Res[I] = Builder.CreateGEP(Base[I], Indices,
+                               GEPI.getName() + ".i" + Twine(I));
+    if (GEPI.isInBounds())
+      if (GetElementPtrInst *NewGEPI = dyn_cast<GetElementPtrInst>(Res[I]))
+        NewGEPI->setIsInBounds();
+  }
+  gather(&GEPI, Res);
+  return true;
+}
+
+bool Scalarizer::visitCastInst(CastInst &CI) {
+  VectorType *VT = dyn_cast<VectorType>(CI.getDestTy());
+  if (!VT)
+    return false;
+
+  unsigned NumElems = VT->getNumElements();
+  IRBuilder<> Builder(CI.getParent(), &CI);
+  Scatterer Op0 = scatter(&CI, CI.getOperand(0));
+  assert(Op0.size() == NumElems && "Mismatched cast");
+  ValueVector Res;
+  Res.resize(NumElems);
+  for (unsigned I = 0; I < NumElems; ++I)
+    Res[I] = Builder.CreateCast(CI.getOpcode(), Op0[I], VT->getElementType(),
+                                CI.getName() + ".i" + Twine(I));
+  gather(&CI, Res);
+  return true;
+}
+
+bool Scalarizer::visitBitCastInst(BitCastInst &BCI) {
+  VectorType *DstVT = dyn_cast<VectorType>(BCI.getDestTy());
+  VectorType *SrcVT = dyn_cast<VectorType>(BCI.getSrcTy());
+  if (!DstVT || !SrcVT)
+    return false;
+
+  unsigned DstNumElems = DstVT->getNumElements();
+  unsigned SrcNumElems = SrcVT->getNumElements();
+  IRBuilder<> Builder(BCI.getParent(), &BCI);
+  Scatterer Op0 = scatter(&BCI, BCI.getOperand(0));
+  ValueVector Res;
+  Res.resize(DstNumElems);
+
+  if (DstNumElems == SrcNumElems) {
+    for (unsigned I = 0; I < DstNumElems; ++I)
+      Res[I] = Builder.CreateBitCast(Op0[I], DstVT->getElementType(),
+                                     BCI.getName() + ".i" + Twine(I));
+  } else if (DstNumElems > SrcNumElems) {
+    // <M x t1> -> <N*M x t2>.  Convert each t1 to <N x t2> and copy the
+    // individual elements to the destination.
+    unsigned FanOut = DstNumElems / SrcNumElems;
+    Type *MidTy = VectorType::get(DstVT->getElementType(), FanOut);
+    unsigned ResI = 0;
+    for (unsigned Op0I = 0; Op0I < SrcNumElems; ++Op0I) {
+      Value *V = Op0[Op0I];
+      Instruction *VI;
+      // Look through any existing bitcasts before converting to <N x t2>.
+      // In the best case, the resulting conversion might be a no-op.
+      while ((VI = dyn_cast<Instruction>(V)) &&
+             VI->getOpcode() == Instruction::BitCast)
+        V = VI->getOperand(0);
+      V = Builder.CreateBitCast(V, MidTy, V->getName() + ".cast");
+      Scatterer Mid = scatter(&BCI, V);
+      for (unsigned MidI = 0; MidI < FanOut; ++MidI)
+        Res[ResI++] = Mid[MidI];
+    }
+  } else {
+    // <N*M x t1> -> <M x t2>.  Convert each group of <N x t1> into a t2.
+    unsigned FanIn = SrcNumElems / DstNumElems;
+    Type *MidTy = VectorType::get(SrcVT->getElementType(), FanIn);
+    unsigned Op0I = 0;
+    for (unsigned ResI = 0; ResI < DstNumElems; ++ResI) {
+      Value *V = UndefValue::get(MidTy);
+      for (unsigned MidI = 0; MidI < FanIn; ++MidI)
+        V = Builder.CreateInsertElement(V, Op0[Op0I++], Builder.getInt32(MidI),
+                                        BCI.getName() + ".i" + Twine(ResI)
+                                        + ".upto" + Twine(MidI));
+      Res[ResI] = Builder.CreateBitCast(V, DstVT->getElementType(),
+                                        BCI.getName() + ".i" + Twine(ResI));
+    }
+  }
+  gather(&BCI, Res);
+  return true;
+}
+
+bool Scalarizer::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
+  VectorType *VT = dyn_cast<VectorType>(SVI.getType());
+  if (!VT)
+    return false;
+
+  unsigned NumElems = VT->getNumElements();
+  Scatterer Op0 = scatter(&SVI, SVI.getOperand(0));
+  Scatterer Op1 = scatter(&SVI, SVI.getOperand(1));
+  ValueVector Res;
+  Res.resize(NumElems);
+
+  for (unsigned I = 0; I < NumElems; ++I) {
+    int Selector = SVI.getMaskValue(I);
+    if (Selector < 0)
+      Res[I] = UndefValue::get(VT->getElementType());
+    else if (unsigned(Selector) < Op0.size())
+      Res[I] = Op0[Selector];
+    else
+      Res[I] = Op1[Selector - Op0.size()];
+  }
+  gather(&SVI, Res);
+  return true;
+}
+
+bool Scalarizer::visitPHINode(PHINode &PHI) {
+  VectorType *VT = dyn_cast<VectorType>(PHI.getType());
+  if (!VT)
+    return false;
+
+  unsigned NumElems = VT->getNumElements();
+  IRBuilder<> Builder(PHI.getParent(), &PHI);
+  ValueVector Res;
+  Res.resize(NumElems);
+
+  unsigned NumOps = PHI.getNumOperands();
+  for (unsigned I = 0; I < NumElems; ++I)
+    Res[I] = Builder.CreatePHI(VT->getElementType(), NumOps,
+                               PHI.getName() + ".i" + Twine(I));
+
+  for (unsigned I = 0; I < NumOps; ++I) {
+    Scatterer Op = scatter(&PHI, PHI.getIncomingValue(I));
+    BasicBlock *IncomingBlock = PHI.getIncomingBlock(I);
+    for (unsigned J = 0; J < NumElems; ++J)
+      cast<PHINode>(Res[J])->addIncoming(Op[J], IncomingBlock);
+  }
+  gather(&PHI, Res);
+  return true;
+}
+
+bool Scalarizer::visitLoadInst(LoadInst &LI) {
+  if (!ScalarizeLoadStore)
+    return false;
+  if (!LI.isSimple())
+    return false;
+
+  VectorLayout Layout;
+  if (!getVectorLayout(LI.getType(), LI.getAlignment(), Layout))
+    return false;
+
+  unsigned NumElems = Layout.VecTy->getNumElements();
+  IRBuilder<> Builder(LI.getParent(), &LI);
+  Scatterer Ptr = scatter(&LI, LI.getPointerOperand());
+  ValueVector Res;
+  Res.resize(NumElems);
+
+  for (unsigned I = 0; I < NumElems; ++I)
+    Res[I] = Builder.CreateAlignedLoad(Ptr[I], Layout.getElemAlign(I),
+                                       LI.getName() + ".i" + Twine(I));
+  gather(&LI, Res);
+  return true;
+}
+
+bool Scalarizer::visitStoreInst(StoreInst &SI) {
+  if (!ScalarizeLoadStore)
+    return false;
+  if (!SI.isSimple())
+    return false;
+
+  VectorLayout Layout;
+  Value *FullValue = SI.getValueOperand();
+  if (!getVectorLayout(FullValue->getType(), SI.getAlignment(), Layout))
+    return false;
+
+  unsigned NumElems = Layout.VecTy->getNumElements();
+  IRBuilder<> Builder(SI.getParent(), &SI);
+  Scatterer Ptr = scatter(&SI, SI.getPointerOperand());
+  Scatterer Val = scatter(&SI, FullValue);
+
+  ValueVector Stores;
+  Stores.resize(NumElems);
+  for (unsigned I = 0; I < NumElems; ++I) {
+    unsigned Align = Layout.getElemAlign(I);
+    Stores[I] = Builder.CreateAlignedStore(Val[I], Ptr[I], Align);
+  }
+  transferMetadata(&SI, Stores);
+  return true;
+}
+
+// Delete the instructions that we scalarized.  If a full vector result
+// is still needed, recreate it using InsertElements.
+bool Scalarizer::finish() {
+  if (Gathered.empty())
+    return false;
+  for (GatherList::iterator GMI = Gathered.begin(), GME = Gathered.end();
+       GMI != GME; ++GMI) {
+    Instruction *Op = GMI->first;
+    ValueVector &CV = *GMI->second;
+    if (!Op->use_empty()) {
+      // The value is still needed, so recreate it using a series of
+      // InsertElements.
+      Type *Ty = Op->getType();
+      Value *Res = UndefValue::get(Ty);
+      BasicBlock *BB = Op->getParent();
+      unsigned Count = Ty->getVectorNumElements();
+      IRBuilder<> Builder(BB, Op);
+      if (isa<PHINode>(Op))
+        Builder.SetInsertPoint(BB, BB->getFirstInsertionPt());
+      for (unsigned I = 0; I < Count; ++I)
+        Res = Builder.CreateInsertElement(Res, CV[I], Builder.getInt32(I),
+                                          Op->getName() + ".upto" + Twine(I));
+      Res->takeName(Op);
+      Op->replaceAllUsesWith(Res);
+    }
+    Op->eraseFromParent();
+  }
+  Gathered.clear();
+  Scattered.clear();
+  return true;
+}
+
+FunctionPass *llvm::createScalarizerPass() {
+  return new Scalarizer();
+}