BBVectorize: Check the types of compare instructions
[oota-llvm.git] / lib / Transforms / Vectorize / BBVectorize.cpp
index 5abb242428a24359e3924e7b54ae9dc505fc8ed4..407cd7b02d4716a2b46521eb9ebf3aaa2764ae54 100644 (file)
@@ -23,6 +23,7 @@
 #include "llvm/IntrinsicInst.h"
 #include "llvm/Intrinsics.h"
 #include "llvm/LLVMContext.h"
+#include "llvm/Metadata.h"
 #include "llvm/Pass.h"
 #include "llvm/Type.h"
 #include "llvm/ADT/DenseMap.h"
@@ -33,6 +34,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/AliasSetTracker.h"
+#include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/ValueHandle.h"
-#include "llvm/Target/TargetData.h"
+#include "llvm/DataLayout.h"
+#include "llvm/TargetTransformInfo.h"
+#include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Transforms/Vectorize.h"
 #include <algorithm>
 #include <map>
 using namespace llvm;
 
+static cl::opt<bool>
+IgnoreTargetInfo("bb-vectorize-ignore-target-info",  cl::init(false),
+  cl::Hidden, cl::desc("Ignore target information"));
+
 static cl::opt<unsigned>
 ReqChainDepth("bb-vectorize-req-chain-depth", cl::init(6), cl::Hidden,
   cl::desc("The required chain depth for vectorization"));
 
+static cl::opt<bool>
+UseChainDepthWithTI("bb-vectorize-use-chain-depth",  cl::init(false),
+  cl::Hidden, cl::desc("Use the chain depth requirement with"
+                       " target information"));
+
 static cl::opt<unsigned>
 SearchLimit("bb-vectorize-search-limit", cl::init(400), cl::Hidden,
   cl::desc("The maximum search distance for instruction pairs"));
@@ -66,6 +79,10 @@ static cl::opt<unsigned>
 MaxIter("bb-vectorize-max-iter", cl::init(0), cl::Hidden,
   cl::desc("The maximum number of pairing iterations"));
 
+static cl::opt<bool>
+Pow2LenOnly("bb-vectorize-pow2-len-only", cl::init(false), cl::Hidden,
+  cl::desc("Don't try to form non-2^n-length vectors"));
+
 static cl::opt<unsigned>
 MaxInsts("bb-vectorize-max-instr-per-group", cl::init(500), cl::Hidden,
   cl::desc("The maximum number of pairable instructions per group"));
@@ -75,6 +92,10 @@ MaxCandPairsForCycleCheck("bb-vectorize-max-cycle-check-pairs", cl::init(200),
   cl::Hidden, cl::desc("The maximum number of candidate pairs with which to use"
                        " a full cycle check"));
 
+static cl::opt<bool>
+NoBools("bb-vectorize-no-bools", cl::init(false), cl::Hidden,
+  cl::desc("Don't try to vectorize boolean (i1) values"));
+
 static cl::opt<bool>
 NoInts("bb-vectorize-no-ints", cl::init(false), cl::Hidden,
   cl::desc("Don't try to vectorize integer values"));
@@ -83,6 +104,11 @@ static cl::opt<bool>
 NoFloats("bb-vectorize-no-floats", cl::init(false), cl::Hidden,
   cl::desc("Don't try to vectorize floating-point values"));
 
+// FIXME: This should default to false once pointer vector support works.
+static cl::opt<bool>
+NoPointers("bb-vectorize-no-pointers", cl::init(/*false*/ true), cl::Hidden,
+  cl::desc("Don't try to vectorize pointer values"));
+
 static cl::opt<bool>
 NoCasts("bb-vectorize-no-casts", cl::init(false), cl::Hidden,
   cl::desc("Don't try to vectorize casting (conversion) operations"));
@@ -95,6 +121,18 @@ static cl::opt<bool>
 NoFMA("bb-vectorize-no-fma", cl::init(false), cl::Hidden,
   cl::desc("Don't try to vectorize the fused-multiply-add intrinsic"));
 
+static cl::opt<bool>
+NoSelect("bb-vectorize-no-select", cl::init(false), cl::Hidden,
+  cl::desc("Don't try to vectorize select instructions"));
+
+static cl::opt<bool>
+NoCmp("bb-vectorize-no-cmp", cl::init(false), cl::Hidden,
+  cl::desc("Don't try to vectorize comparison instructions"));
+
+static cl::opt<bool>
+NoGEP("bb-vectorize-no-gep", cl::init(false), cl::Hidden,
+  cl::desc("Don't try to vectorize getelementptr instructions"));
+
 static cl::opt<bool>
 NoMemOps("bb-vectorize-no-mem-ops", cl::init(false), cl::Hidden,
   cl::desc("Don't try to vectorize loads and stores"));
@@ -133,6 +171,12 @@ DebugCycleCheck("bb-vectorize-debug-cycle-check",
   cl::init(false), cl::Hidden,
   cl::desc("When debugging is enabled, output information on the"
            " cycle-checking process"));
+
+static cl::opt<bool>
+PrintAfterEveryPair("bb-vectorize-debug-print-after-every-pair",
+  cl::init(false), cl::Hidden,
+  cl::desc("When debugging is enabled, dump the basic block after"
+           " every pair is fused"));
 #endif
 
 STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize");
@@ -140,19 +184,30 @@ STATISTIC(NumFusedOps, "Number of operations fused by bb-vectorize");
 namespace {
   struct BBVectorize : public BasicBlockPass {
     static char ID; // Pass identification, replacement for typeid
-    BBVectorize() : BasicBlockPass(ID) {
+
+    const VectorizeConfig Config;
+
+    BBVectorize(const VectorizeConfig &C = VectorizeConfig())
+      : BasicBlockPass(ID), Config(C) {
       initializeBBVectorizePass(*PassRegistry::getPassRegistry());
     }
 
-    BBVectorize(Pass *P) : BasicBlockPass(ID) {
+    BBVectorize(Pass *P, const VectorizeConfig &C)
+      : BasicBlockPass(ID), Config(C) {
       AA = &P->getAnalysis<AliasAnalysis>();
+      DT = &P->getAnalysis<DominatorTree>();
       SE = &P->getAnalysis<ScalarEvolution>();
-      TD = P->getAnalysisIfAvailable<TargetData>();
+      TD = P->getAnalysisIfAvailable<DataLayout>();
+      TTI = IgnoreTargetInfo ? 0 :
+        P->getAnalysisIfAvailable<TargetTransformInfo>();
+      VTTI = TTI ? TTI->getVectorTargetTransformInfo() : 0;
     }
 
     typedef std::pair<Value *, Value *> ValuePair;
+    typedef std::pair<ValuePair, int> ValuePairWithCost;
     typedef std::pair<ValuePair, size_t> ValuePairWithDepth;
     typedef std::pair<ValuePair, ValuePair> VPPair; // A ValuePair pair
+    typedef std::pair<VPPair, unsigned> VPPairWithType;
     typedef std::pair<std::multimap<Value *, Value *>::iterator,
               std::multimap<Value *, Value *>::iterator> VPIteratorPair;
     typedef std::pair<std::multimap<ValuePair, ValuePair>::iterator,
@@ -160,21 +215,36 @@ namespace {
                 VPPIteratorPair;
 
     AliasAnalysis *AA;
+    DominatorTree *DT;
     ScalarEvolution *SE;
-    TargetData *TD;
+    DataLayout *TD;
+    TargetTransformInfo *TTI;
+    const VectorTargetTransformInfo *VTTI;
 
     // FIXME: const correct?
 
-    bool vectorizePairs(BasicBlock &BB);
+    bool vectorizePairs(BasicBlock &BB, bool NonPow2Len = false);
 
     bool getCandidatePairs(BasicBlock &BB,
                        BasicBlock::iterator &Start,
                        std::multimap<Value *, Value *> &CandidatePairs,
-                       std::vector<Value *> &PairableInsts);
+                       DenseSet<ValuePair> &FixedOrderPairs,
+                       DenseMap<ValuePair, int> &CandidatePairCostSavings,
+                       std::vector<Value *> &PairableInsts, bool NonPow2Len);
+
+    // FIXME: The current implementation does not account for pairs that
+    // are connected in multiple ways. For example:
+    //   C1 = A1 / A2; C2 = A2 / A1 (which may be both direct and a swap)
+    enum PairConnectionType {
+      PairConnectionDirect,
+      PairConnectionSwap,
+      PairConnectionSplat
+    };
 
     void computeConnectedPairs(std::multimap<Value *, Value *> &CandidatePairs,
                        std::vector<Value *> &PairableInsts,
-                       std::multimap<ValuePair, ValuePair> &ConnectedPairs);
+                       std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                       DenseMap<VPPair, unsigned> &PairConnectionTypes);
 
     void buildDepMap(BasicBlock &BB,
                        std::multimap<Value *, Value *> &CandidatePairs,
@@ -182,19 +252,29 @@ namespace {
                        DenseSet<ValuePair> &PairableInstUsers);
 
     void choosePairs(std::multimap<Value *, Value *> &CandidatePairs,
+                        DenseMap<ValuePair, int> &CandidatePairCostSavings,
                         std::vector<Value *> &PairableInsts,
+                        DenseSet<ValuePair> &FixedOrderPairs,
+                        DenseMap<VPPair, unsigned> &PairConnectionTypes,
                         std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                        std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
                         DenseSet<ValuePair> &PairableInstUsers,
                         DenseMap<Value *, Value *>& ChosenPairs);
 
     void fuseChosenPairs(BasicBlock &BB,
                      std::vector<Value *> &PairableInsts,
-                     DenseMap<Value *, Value *>& ChosenPairs);
+                     DenseMap<Value *, Value *>& ChosenPairs,
+                     DenseSet<ValuePair> &FixedOrderPairs,
+                     DenseMap<VPPair, unsigned> &PairConnectionTypes,
+                     std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                     std::multimap<ValuePair, ValuePair> &ConnectedPairDeps);
+
 
     bool isInstVectorizable(Instruction *I, bool &IsSimpleLoadStore);
 
     bool areInstsCompatible(Instruction *I, Instruction *J,
-                       bool IsSimpleLoadStore);
+                       bool IsSimpleLoadStore, bool NonPow2Len,
+                       int &CostSavings, int &FixedOrder);
 
     bool trackUsesOfI(DenseSet<Value *> &Users,
                       AliasSetTracker &WriteSet, Instruction *I,
@@ -205,6 +285,7 @@ namespace {
                       std::multimap<Value *, Value *> &CandidatePairs,
                       std::vector<Value *> &PairableInsts,
                       std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                      DenseMap<VPPair, unsigned> &PairConnectionTypes,
                       ValuePair P);
 
     bool pairsConflict(ValuePair P, ValuePair Q,
@@ -236,36 +317,46 @@ namespace {
 
     void findBestTreeFor(
                       std::multimap<Value *, Value *> &CandidatePairs,
+                      DenseMap<ValuePair, int> &CandidatePairCostSavings,
                       std::vector<Value *> &PairableInsts,
+                      DenseSet<ValuePair> &FixedOrderPairs,
+                      DenseMap<VPPair, unsigned> &PairConnectionTypes,
                       std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                      std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
                       DenseSet<ValuePair> &PairableInstUsers,
                       std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
                       DenseMap<Value *, Value *> &ChosenPairs,
                       DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth,
-                      size_t &BestEffSize, VPIteratorPair ChoiceRange,
+                      int &BestEffSize, VPIteratorPair ChoiceRange,
                       bool UseCycleCheck);
 
     Value *getReplacementPointerInput(LLVMContext& Context, Instruction *I,
-                     Instruction *J, unsigned o, bool &FlipMemInputs);
+                     Instruction *J, unsigned o);
 
     void fillNewShuffleMask(LLVMContext& Context, Instruction *J,
-                     unsigned NumElem, unsigned MaskOffset, unsigned NumInElem,
-                     unsigned IdxOffset, std::vector<Constant*> &Mask);
+                     unsigned MaskOffset, unsigned NumInElem,
+                     unsigned NumInElem1, unsigned IdxOffset,
+                     std::vector<Constant*> &Mask);
 
     Value *getReplacementShuffleMask(LLVMContext& Context, Instruction *I,
                      Instruction *J);
 
+    bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J,
+                       unsigned o, Value *&LOp, unsigned numElemL,
+                       Type *ArgTypeL, Type *ArgTypeR, bool IBeforeJ,
+                       unsigned IdxOff = 0);
+
     Value *getReplacementInput(LLVMContext& Context, Instruction *I,
-                     Instruction *J, unsigned o, bool FlipMemInputs);
+                     Instruction *J, unsigned o, bool IBeforeJ);
 
     void getReplacementInputsForPair(LLVMContext& Context, Instruction *I,
                      Instruction *J, SmallVector<Value *, 3> &ReplacedOperands,
-                     bool &FlipMemInputs);
+                     bool IBeforeJ);
 
     void replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
                      Instruction *J, Instruction *K,
                      Instruction *&InsertionPt, Instruction *&K1,
-                     Instruction *&K2, bool &FlipMemInputs);
+                     Instruction *&K2);
 
     void collectPairLoadMoveSet(BasicBlock &BB,
                      DenseMap<Value *, Value *> &ChosenPairs,
@@ -286,14 +377,27 @@ namespace {
                      Instruction *&InsertionPt,
                      Instruction *I, Instruction *J);
 
+    void combineMetadata(Instruction *K, const Instruction *J);
+
     bool vectorizeBB(BasicBlock &BB) {
+      if (!DT->isReachableFromEntry(&BB)) {
+        DEBUG(dbgs() << "BBV: skipping unreachable " << BB.getName() <<
+              " in " << BB.getParent()->getName() << "\n");
+        return false;
+      }
+
+      DEBUG(if (VTTI) dbgs() << "BBV: using target information\n");
+
       bool changed = false;
       // Iterate a sufficient number of times to merge types of size 1 bit,
       // then 2 bits, then 4, etc. up to half of the target vector width of the
       // target vector register.
-      for (unsigned v = 2, n = 1; v <= VectorBits && (!MaxIter || n <= MaxIter);
+      unsigned n = 1;
+      for (unsigned v = 2;
+           (VTTI || v <= Config.VectorBits) &&
+           (!Config.MaxIter || n <= Config.MaxIter);
            v *= 2, ++n) {
-        DEBUG(dbgs() << "BBV: fusing loop #" << n << 
+        DEBUG(dbgs() << "BBV: fusing loop #" << n <<
               " for " << BB.getName() << " in " <<
               BB.getParent()->getName() << "...\n");
         if (vectorizePairs(BB))
@@ -302,14 +406,28 @@ namespace {
           break;
       }
 
+      if (changed && !Pow2LenOnly) {
+        ++n;
+        for (; !Config.MaxIter || n <= Config.MaxIter; ++n) {
+          DEBUG(dbgs() << "BBV: fusing for non-2^n-length vectors loop #: " <<
+                n << " for " << BB.getName() << " in " <<
+                BB.getParent()->getName() << "...\n");
+          if (!vectorizePairs(BB, true)) break;
+        }
+      }
+
       DEBUG(dbgs() << "BBV: done!\n");
       return changed;
     }
 
     virtual bool runOnBasicBlock(BasicBlock &BB) {
       AA = &getAnalysis<AliasAnalysis>();
+      DT = &getAnalysis<DominatorTree>();
       SE = &getAnalysis<ScalarEvolution>();
-      TD = getAnalysisIfAvailable<TargetData>();
+      TD = getAnalysisIfAvailable<DataLayout>();
+      TTI = IgnoreTargetInfo ? 0 :
+        getAnalysisIfAvailable<TargetTransformInfo>();
+      VTTI = TTI ? TTI->getVectorTargetTransformInfo() : 0;
 
       return vectorizeBB(BB);
     }
@@ -317,21 +435,59 @@ namespace {
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       BasicBlockPass::getAnalysisUsage(AU);
       AU.addRequired<AliasAnalysis>();
+      AU.addRequired<DominatorTree>();
       AU.addRequired<ScalarEvolution>();
       AU.addPreserved<AliasAnalysis>();
+      AU.addPreserved<DominatorTree>();
       AU.addPreserved<ScalarEvolution>();
       AU.setPreservesCFG();
     }
 
-    // This returns the vector type that holds a pair of the provided type.
-    // If the provided type is already a vector, then its length is doubled.
-    static inline VectorType *getVecTypeForPair(Type *ElemTy) {
+    static inline VectorType *getVecTypeForPair(Type *ElemTy, Type *Elem2Ty) {
+      assert(ElemTy->getScalarType() == Elem2Ty->getScalarType() &&
+             "Cannot form vector from incompatible scalar types");
+      Type *STy = ElemTy->getScalarType();
+
+      unsigned numElem;
       if (VectorType *VTy = dyn_cast<VectorType>(ElemTy)) {
-        unsigned numElem = VTy->getNumElements();
-        return VectorType::get(ElemTy->getScalarType(), numElem*2);
+        numElem = VTy->getNumElements();
+      } else {
+        numElem = 1;
       }
 
-      return VectorType::get(ElemTy, 2);
+      if (VectorType *VTy = dyn_cast<VectorType>(Elem2Ty)) {
+        numElem += VTy->getNumElements();
+      } else {
+        numElem += 1;
+      }
+
+      return VectorType::get(STy, numElem);
+    }
+
+    static inline void getInstructionTypes(Instruction *I,
+                                           Type *&T1, Type *&T2) {
+      if (isa<StoreInst>(I)) {
+        // For stores, it is the value type, not the pointer type that matters
+        // because the value is what will come from a vector register.
+  
+        Value *IVal = cast<StoreInst>(I)->getValueOperand();
+        T1 = IVal->getType();
+      } else {
+        T1 = I->getType();
+      }
+  
+      if (I->isCast())
+        T2 = cast<CastInst>(I)->getSrcTy();
+      else
+        T2 = T1;
+
+      if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
+        T2 = SI->getCondition()->getType();
+      } else if (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(I)) {
+        T2 = SI->getOperand(0)->getType();
+      } else if (CmpInst *CI = dyn_cast<CmpInst>(I)) {
+        T2 = CI->getOperand(0)->getType();
+      }
     }
 
     // Returns the weight associated with the provided value. A chain of
@@ -343,7 +499,7 @@ namespace {
     // candidate chains where longer chains are considered to be better.
     // Note: when this function returns 0, the resulting instructions are
     // not actually fused.
-    static inline size_t getDepthFactor(Value *V) {
+    inline size_t getDepthFactor(Value *V) {
       // InsertElement and ExtractElement have a depth factor of zero. This is
       // for two reasons: First, they cannot be usefully fused. Second, because
       // the pass generates a lot of these, they can confuse the simple metric
@@ -357,8 +513,64 @@ namespace {
 
       // Give a load or store half of the required depth so that load/store
       // pairs will vectorize.
-      if (!NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V)))
-        return ReqChainDepth/2;
+      if (!Config.NoMemOpBoost && (isa<LoadInst>(V) || isa<StoreInst>(V)))
+        return Config.ReqChainDepth/2;
+
+      return 1;
+    }
+
+    // Returns the cost of the provided instruction using VTTI.
+    // This does not handle loads and stores.
+    unsigned getInstrCost(unsigned Opcode, Type *T1, Type *T2) {
+      switch (Opcode) {
+      default: break;
+      case Instruction::GetElementPtr:
+        // We mark this instruction as zero-cost because scalar GEPs are usually
+        // lowered to the intruction addressing mode. At the moment we don't
+        // generate vector GEPs.
+        return 0;
+      case Instruction::Br:
+        return VTTI->getCFInstrCost(Opcode);
+      case Instruction::PHI:
+        return 0;
+      case Instruction::Add:
+      case Instruction::FAdd:
+      case Instruction::Sub:
+      case Instruction::FSub:
+      case Instruction::Mul:
+      case Instruction::FMul:
+      case Instruction::UDiv:
+      case Instruction::SDiv:
+      case Instruction::FDiv:
+      case Instruction::URem:
+      case Instruction::SRem:
+      case Instruction::FRem:
+      case Instruction::Shl:
+      case Instruction::LShr:
+      case Instruction::AShr:
+      case Instruction::And:
+      case Instruction::Or:
+      case Instruction::Xor:
+        return VTTI->getArithmeticInstrCost(Opcode, T1);
+      case Instruction::Select:
+      case Instruction::ICmp:
+      case Instruction::FCmp:
+        return VTTI->getCmpSelInstrCost(Opcode, T1, T2);
+      case Instruction::ZExt:
+      case Instruction::SExt:
+      case Instruction::FPToUI:
+      case Instruction::FPToSI:
+      case Instruction::FPExt:
+      case Instruction::PtrToInt:
+      case Instruction::IntToPtr:
+      case Instruction::SIToFP:
+      case Instruction::UIToFP:
+      case Instruction::Trunc:
+      case Instruction::FPTrunc:
+      case Instruction::BitCast:
+      case Instruction::ShuffleVector:
+        return VTTI->getCastInstrCost(Opcode, T1, T2);
+      }
 
       return 1;
     }
@@ -367,24 +579,33 @@ namespace {
     // true if the offset could be determined to be some constant value.
     // For example, if OffsetInElmts == 1, then J accesses the memory directly
     // after I; if OffsetInElmts == -1 then I accesses the memory
-    // directly after J. This function assumes that both instructions
-    // have the same type.
+    // directly after J.
     bool getPairPtrInfo(Instruction *I, Instruction *J,
         Value *&IPtr, Value *&JPtr, unsigned &IAlignment, unsigned &JAlignment,
-        int64_t &OffsetInElmts) {
+        unsigned &IAddressSpace, unsigned &JAddressSpace,
+        int64_t &OffsetInElmts, bool ComputeOffset = true) {
       OffsetInElmts = 0;
-      if (isa<LoadInst>(I)) {
-        IPtr = cast<LoadInst>(I)->getPointerOperand();
-        JPtr = cast<LoadInst>(J)->getPointerOperand();
-        IAlignment = cast<LoadInst>(I)->getAlignment();
-        JAlignment = cast<LoadInst>(J)->getAlignment();
+      if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
+        LoadInst *LJ = cast<LoadInst>(J);
+        IPtr = LI->getPointerOperand();
+        JPtr = LJ->getPointerOperand();
+        IAlignment = LI->getAlignment();
+        JAlignment = LJ->getAlignment();
+        IAddressSpace = LI->getPointerAddressSpace();
+        JAddressSpace = LJ->getPointerAddressSpace();
       } else {
-        IPtr = cast<StoreInst>(I)->getPointerOperand();
-        JPtr = cast<StoreInst>(J)->getPointerOperand();
-        IAlignment = cast<StoreInst>(I)->getAlignment();
-        JAlignment = cast<StoreInst>(J)->getAlignment();
+        StoreInst *SI = cast<StoreInst>(I), *SJ = cast<StoreInst>(J);
+        IPtr = SI->getPointerOperand();
+        JPtr = SJ->getPointerOperand();
+        IAlignment = SI->getAlignment();
+        JAlignment = SJ->getAlignment();
+        IAddressSpace = SI->getPointerAddressSpace();
+        JAddressSpace = SJ->getPointerAddressSpace();
       }
 
+      if (!ComputeOffset)
+        return true;
+
       const SCEV *IPtrSCEV = SE->getSCEV(IPtr);
       const SCEV *JPtrSCEV = SE->getSCEV(JPtr);
 
@@ -400,7 +621,12 @@ namespace {
         Type *VTy = cast<PointerType>(IPtr->getType())->getElementType();
         int64_t VTyTSS = (int64_t) TD->getTypeStoreSize(VTy);
 
-        assert(VTy == cast<PointerType>(JPtr->getType())->getElementType());
+        Type *VTy2 = cast<PointerType>(JPtr->getType())->getElementType();
+        if (VTy != VTy2 && Offset < 0) {
+          int64_t VTy2TSS = (int64_t) TD->getTypeStoreSize(VTy2);
+          OffsetInElmts = Offset/VTy2TSS;
+          return (abs64(Offset) % VTy2TSS) == 0;
+        }
 
         OffsetInElmts = Offset/VTyTSS;
         return (abs64(Offset) % VTyTSS) == 0;
@@ -431,9 +657,9 @@ namespace {
       case Intrinsic::exp:
       case Intrinsic::exp2:
       case Intrinsic::pow:
-        return !NoMath;
+        return Config.VectorizeMath;
       case Intrinsic::fma:
-        return !NoFMA;
+        return Config.VectorizeFMA;
       }
     }
 
@@ -453,18 +679,25 @@ namespace {
 
   // This function implements one vectorization iteration on the provided
   // basic block. It returns true if the block is changed.
-  bool BBVectorize::vectorizePairs(BasicBlock &BB) {
+  bool BBVectorize::vectorizePairs(BasicBlock &BB, bool NonPow2Len) {
     bool ShouldContinue;
     BasicBlock::iterator Start = BB.getFirstInsertionPt();
 
     std::vector<Value *> AllPairableInsts;
     DenseMap<Value *, Value *> AllChosenPairs;
+    DenseSet<ValuePair> AllFixedOrderPairs;
+    DenseMap<VPPair, unsigned> AllPairConnectionTypes;
+    std::multimap<ValuePair, ValuePair> AllConnectedPairs, AllConnectedPairDeps;
 
     do {
       std::vector<Value *> PairableInsts;
       std::multimap<Value *, Value *> CandidatePairs;
+      DenseSet<ValuePair> FixedOrderPairs;
+      DenseMap<ValuePair, int> CandidatePairCostSavings;
       ShouldContinue = getCandidatePairs(BB, Start, CandidatePairs,
-                                         PairableInsts);
+                                         FixedOrderPairs,
+                                         CandidatePairCostSavings,
+                                         PairableInsts, NonPow2Len);
       if (PairableInsts.empty()) continue;
 
       // Now we have a map of all of the pairable instructions and we need to
@@ -476,10 +709,18 @@ namespace {
       // Note that it only matters that both members of the second pair use some
       // element of the first pair (to allow for splatting).
 
-      std::multimap<ValuePair, ValuePair> ConnectedPairs;
-      computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs);
+      std::multimap<ValuePair, ValuePair> ConnectedPairs, ConnectedPairDeps;
+      DenseMap<VPPair, unsigned> PairConnectionTypes;
+      computeConnectedPairs(CandidatePairs, PairableInsts, ConnectedPairs,
+                            PairConnectionTypes);
       if (ConnectedPairs.empty()) continue;
 
+      for (std::multimap<ValuePair, ValuePair>::iterator
+           I = ConnectedPairs.begin(), IE = ConnectedPairs.end();
+           I != IE; ++I) {
+        ConnectedPairDeps.insert(VPPair(I->second, I->first));
+      }
+
       // Build the pairable-instruction dependency map
       DenseSet<ValuePair> PairableInstUsers;
       buildDepMap(BB, CandidatePairs, PairableInsts, PairableInstUsers);
@@ -491,13 +732,48 @@ namespace {
       // variables.
 
       DenseMap<Value *, Value *> ChosenPairs;
-      choosePairs(CandidatePairs, PairableInsts, ConnectedPairs,
+      choosePairs(CandidatePairs, CandidatePairCostSavings,
+        PairableInsts, FixedOrderPairs, PairConnectionTypes,
+        ConnectedPairs, ConnectedPairDeps,
         PairableInstUsers, ChosenPairs);
 
       if (ChosenPairs.empty()) continue;
       AllPairableInsts.insert(AllPairableInsts.end(), PairableInsts.begin(),
                               PairableInsts.end());
       AllChosenPairs.insert(ChosenPairs.begin(), ChosenPairs.end());
+
+      // Only for the chosen pairs, propagate information on fixed-order pairs,
+      // pair connections, and their types to the data structures used by the
+      // pair fusion procedures.
+      for (DenseMap<Value *, Value *>::iterator I = ChosenPairs.begin(),
+           IE = ChosenPairs.end(); I != IE; ++I) {
+        if (FixedOrderPairs.count(*I))
+          AllFixedOrderPairs.insert(*I);
+        else if (FixedOrderPairs.count(ValuePair(I->second, I->first)))
+          AllFixedOrderPairs.insert(ValuePair(I->second, I->first));
+
+        for (DenseMap<Value *, Value *>::iterator J = ChosenPairs.begin();
+             J != IE; ++J) {
+          DenseMap<VPPair, unsigned>::iterator K =
+            PairConnectionTypes.find(VPPair(*I, *J));
+          if (K != PairConnectionTypes.end()) {
+            AllPairConnectionTypes.insert(*K);
+          } else {
+            K = PairConnectionTypes.find(VPPair(*J, *I));
+            if (K != PairConnectionTypes.end())
+              AllPairConnectionTypes.insert(*K);
+          }
+        }
+      }
+
+      for (std::multimap<ValuePair, ValuePair>::iterator
+           I = ConnectedPairs.begin(), IE = ConnectedPairs.end();
+           I != IE; ++I) {
+        if (AllPairConnectionTypes.count(*I)) {
+          AllConnectedPairs.insert(*I);
+          AllConnectedPairDeps.insert(VPPair(I->second, I->first));
+        }
+      }
     } while (ShouldContinue);
 
     if (AllChosenPairs.empty()) return false;
@@ -510,7 +786,13 @@ namespace {
     // replaced with a vector_extract on the result.  Subsequent optimization
     // passes should coalesce the build/extract combinations.
 
-    fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs);
+    fuseChosenPairs(BB, AllPairableInsts, AllChosenPairs, AllFixedOrderPairs,
+                    AllPairConnectionTypes,
+                    AllConnectedPairs, AllConnectedPairDeps);
+
+    // It is important to cleanup here so that future iterations of this
+    // function have less work to do.
+    (void) SimplifyInstructionsInBlock(&BB, TD, AA->getTargetLibraryInfo());
     return true;
   }
 
@@ -527,24 +809,37 @@ namespace {
     } else if (LoadInst *L = dyn_cast<LoadInst>(I)) {
       // Vectorize simple loads if possbile:
       IsSimpleLoadStore = L->isSimple();
-      if (!IsSimpleLoadStore || NoMemOps)
+      if (!IsSimpleLoadStore || !Config.VectorizeMemOps)
         return false;
     } else if (StoreInst *S = dyn_cast<StoreInst>(I)) {
       // Vectorize simple stores if possbile:
       IsSimpleLoadStore = S->isSimple();
-      if (!IsSimpleLoadStore || NoMemOps)
+      if (!IsSimpleLoadStore || !Config.VectorizeMemOps)
         return false;
     } else if (CastInst *C = dyn_cast<CastInst>(I)) {
       // We can vectorize casts, but not casts of pointer types, etc.
-      if (NoCasts)
+      if (!Config.VectorizeCasts)
         return false;
 
       Type *SrcTy = C->getSrcTy();
-      if (!SrcTy->isSingleValueType() || SrcTy->isPointerTy())
+      if (!SrcTy->isSingleValueType())
         return false;
 
       Type *DestTy = C->getDestTy();
-      if (!DestTy->isSingleValueType() || DestTy->isPointerTy())
+      if (!DestTy->isSingleValueType())
+        return false;
+    } else if (isa<SelectInst>(I)) {
+      if (!Config.VectorizeSelect)
+        return false;
+    } else if (isa<CmpInst>(I)) {
+      if (!Config.VectorizeCmp)
+        return false;
+    } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(I)) {
+      if (!Config.VectorizeGEP)
+        return false;
+
+      // Currently, vector GEPs exist only with one index.
+      if (G->getNumIndices() != 1)
         return false;
     } else if (!(I->isBinaryOp() || isa<ShuffleVectorInst>(I) ||
         isa<ExtractElementInst>(I) || isa<InsertElementInst>(I))) {
@@ -556,34 +851,46 @@ namespace {
       return false;
 
     Type *T1, *T2;
-    if (isa<StoreInst>(I)) {
-      // For stores, it is the value type, not the pointer type that matters
-      // because the value is what will come from a vector register.
+    getInstructionTypes(I, T1, T2);
 
-      Value *IVal = cast<StoreInst>(I)->getValueOperand();
-      T1 = IVal->getType();
+    // Not every type can be vectorized...
+    if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) ||
+        !(VectorType::isValidElementType(T2) || T2->isVectorTy()))
+      return false;
+
+    if (T1->getScalarSizeInBits() == 1) {
+      if (!Config.VectorizeBools)
+        return false;
     } else {
-      T1 = I->getType();
+      if (!Config.VectorizeInts && T1->isIntOrIntVectorTy())
+        return false;
     }
 
-    if (I->isCast())
-      T2 = cast<CastInst>(I)->getSrcTy();
-    else
-      T2 = T1;
+    if (T2->getScalarSizeInBits() == 1) {
+      if (!Config.VectorizeBools)
+        return false;
+    } else {
+      if (!Config.VectorizeInts && T2->isIntOrIntVectorTy())
+        return false;
+    }
 
-    // Not every type can be vectorized...
-    if (!(VectorType::isValidElementType(T1) || T1->isVectorTy()) ||
-        !(VectorType::isValidElementType(T2) || T2->isVectorTy()))
+    if (!Config.VectorizeFloats
+        && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy()))
       return false;
 
-    if (NoInts && (T1->isIntOrIntVectorTy() || T2->isIntOrIntVectorTy()))
+    // Don't vectorize target-specific types.
+    if (T1->isX86_FP80Ty() || T1->isPPC_FP128Ty() || T1->isX86_MMXTy())
+      return false;
+    if (T2->isX86_FP80Ty() || T2->isPPC_FP128Ty() || T2->isX86_MMXTy())
       return false;
 
-    if (NoFloats && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy()))
+    if ((!Config.VectorizePointers || TD == 0) &&
+        (T1->getScalarType()->isPointerTy() ||
+         T2->getScalarType()->isPointerTy()))
       return false;
 
-    if (T1->getPrimitiveSizeInBits() > VectorBits/2 ||
-        T2->getPrimitiveSizeInBits() > VectorBits/2)
+    if (!VTTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits ||
+                  T2->getPrimitiveSizeInBits() >= Config.VectorBits))
       return false;
 
     return true;
@@ -594,67 +901,104 @@ namespace {
   // that I has already been determined to be vectorizable and that J is not
   // in the use tree of I.
   bool BBVectorize::areInstsCompatible(Instruction *I, Instruction *J,
-                       bool IsSimpleLoadStore) {
+                       bool IsSimpleLoadStore, bool NonPow2Len,
+                       int &CostSavings, int &FixedOrder) {
     DEBUG(if (DebugInstructionExamination) dbgs() << "BBV: looking at " << *I <<
                      " <-> " << *J << "\n");
 
+    CostSavings = 0;
+    FixedOrder = 0;
+
     // Loads and stores can be merged if they have different alignments,
     // but are otherwise the same.
-    LoadInst *LI, *LJ;
-    StoreInst *SI, *SJ;
-    if ((LI = dyn_cast<LoadInst>(I)) && (LJ = dyn_cast<LoadInst>(J))) {
-      if (I->getType() != J->getType())
-        return false;
+    if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment |
+                      (NonPow2Len ? Instruction::CompareUsingScalarTypes : 0)))
+      return false;
 
-      if (LI->getPointerOperand()->getType() !=
-            LJ->getPointerOperand()->getType() ||
-          LI->isVolatile() != LJ->isVolatile() ||
-          LI->getOrdering() != LJ->getOrdering() ||
-          LI->getSynchScope() != LJ->getSynchScope())
-        return false; 
-    } else if ((SI = dyn_cast<StoreInst>(I)) && (SJ = dyn_cast<StoreInst>(J))) {
-      if (SI->getValueOperand()->getType() !=
-            SJ->getValueOperand()->getType() ||
-          SI->getPointerOperand()->getType() !=
-            SJ->getPointerOperand()->getType() ||
-          SI->isVolatile() != SJ->isVolatile() ||
-          SI->getOrdering() != SJ->getOrdering() ||
-          SI->getSynchScope() != SJ->getSynchScope())
-        return false;
-    } else if (!J->isSameOperationAs(I)) {
+    Type *IT1, *IT2, *JT1, *JT2;
+    getInstructionTypes(I, IT1, IT2);
+    getInstructionTypes(J, JT1, JT2);
+    unsigned MaxTypeBits = std::max(
+      IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(),
+      IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits());
+    if (!VTTI && MaxTypeBits > Config.VectorBits)
       return false;
-    }
+
     // FIXME: handle addsub-type operations!
 
     if (IsSimpleLoadStore) {
       Value *IPtr, *JPtr;
-      unsigned IAlignment, JAlignment;
+      unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
       int64_t OffsetInElmts = 0;
       if (getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
+            IAddressSpace, JAddressSpace,
             OffsetInElmts) && abs64(OffsetInElmts) == 1) {
-        if (AlignedOnly) {
-          Type *aType = isa<StoreInst>(I) ?
-            cast<StoreInst>(I)->getValueOperand()->getType() : I->getType();
+        FixedOrder = (int) OffsetInElmts;
+        unsigned BottomAlignment = IAlignment;
+        if (OffsetInElmts < 0) BottomAlignment = JAlignment;
+
+        Type *aTypeI = isa<StoreInst>(I) ?
+          cast<StoreInst>(I)->getValueOperand()->getType() : I->getType();
+        Type *aTypeJ = isa<StoreInst>(J) ?
+          cast<StoreInst>(J)->getValueOperand()->getType() : J->getType();
+        Type *VType = getVecTypeForPair(aTypeI, aTypeJ);
+
+        if (Config.AlignedOnly) {
           // An aligned load or store is possible only if the instruction
           // with the lower offset has an alignment suitable for the
           // vector type.
 
-          unsigned BottomAlignment = IAlignment;
-          if (OffsetInElmts < 0) BottomAlignment = JAlignment;
-
-          Type *VType = getVecTypeForPair(aType);
           unsigned VecAlignment = TD->getPrefTypeAlignment(VType);
           if (BottomAlignment < VecAlignment)
             return false;
         }
+
+        if (VTTI) {
+          unsigned ICost = VTTI->getMemoryOpCost(I->getOpcode(), I->getType(),
+                                                 IAlignment, IAddressSpace);
+          unsigned JCost = VTTI->getMemoryOpCost(J->getOpcode(), J->getType(),
+                                                 JAlignment, JAddressSpace);
+          unsigned VCost = VTTI->getMemoryOpCost(I->getOpcode(), VType,
+                                                 BottomAlignment,
+                                                 IAddressSpace);
+          if (VCost > ICost + JCost)
+            return false;
+
+          // We don't want to fuse to a type that will be split, even
+          // if the two input types will also be split and there is no other
+          // associated cost.
+          unsigned VParts = VTTI->getNumberOfParts(VType);
+          if (VParts > 1)
+            return false;
+          else if (!VParts && VCost == ICost + JCost)
+            return false;
+
+          CostSavings = ICost + JCost - VCost;
+        }
       } else {
         return false;
       }
-    } else if (isa<ShuffleVectorInst>(I)) {
-      // Only merge two shuffles if they're both constant
-      return isa<Constant>(I->getOperand(2)) &&
-             isa<Constant>(J->getOperand(2));
-      // FIXME: We may want to vectorize non-constant shuffles also.
+    } else if (VTTI) {
+      unsigned ICost = getInstrCost(I->getOpcode(), IT1, IT2);
+      unsigned JCost = getInstrCost(J->getOpcode(), JT1, JT2);
+      Type *VT1 = getVecTypeForPair(IT1, JT1),
+           *VT2 = getVecTypeForPair(IT2, JT2);
+      unsigned VCost = getInstrCost(I->getOpcode(), VT1, VT2);
+
+      if (VCost > ICost + JCost)
+        return false;
+
+      // We don't want to fuse to a type that will be split, even
+      // if the two input types will also be split and there is no other
+      // associated cost.
+      unsigned VParts1 = VTTI->getNumberOfParts(VT1),
+               VParts2 = VTTI->getNumberOfParts(VT2);
+      if (VParts1 > 1 || VParts2 > 1)
+        return false;
+      else if ((!VParts1 || !VParts2) && VCost == ICost + JCost)
+        return false;
+
+      CostSavings = ICost + JCost - VCost;
     }
 
     // The powi intrinsic is special because only the first argument is
@@ -737,7 +1081,9 @@ namespace {
   bool BBVectorize::getCandidatePairs(BasicBlock &BB,
                        BasicBlock::iterator &Start,
                        std::multimap<Value *, Value *> &CandidatePairs,
-                       std::vector<Value *> &PairableInsts) {
+                       DenseSet<ValuePair> &FixedOrderPairs,
+                       DenseMap<ValuePair, int> &CandidatePairCostSavings,
+                       std::vector<Value *> &PairableInsts, bool NonPow2Len) {
     BasicBlock::iterator E = BB.end();
     if (Start == E) return false;
 
@@ -753,12 +1099,12 @@ namespace {
       AliasSetTracker WriteSet(*AA);
       bool JAfterStart = IAfterStart;
       BasicBlock::iterator J = llvm::next(I);
-      for (unsigned ss = 0; J != E && ss <= SearchLimit; ++J, ++ss) {
+      for (unsigned ss = 0; J != E && ss <= Config.SearchLimit; ++J, ++ss) {
         if (J == Start) JAfterStart = true;
 
         // Determine if J uses I, if so, exit the loop.
-        bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !FastDep);
-        if (FastDep) {
+        bool UsesI = trackUsesOfI(Users, WriteSet, I, J, !Config.FastDep);
+        if (Config.FastDep) {
           // Note: For this heuristic to be effective, independent operations
           // must tend to be intermixed. This is likely to be true from some
           // kinds of grouped loop unrolling (but not the generic LLVM pass),
@@ -773,7 +1119,9 @@ namespace {
 
         // J does not use I, and comes before the first use of I, so it can be
         // merged with I if the instructions are compatible.
-        if (!areInstsCompatible(I, J, IsSimpleLoadStore)) continue;
+        int CostSavings, FixedOrder;
+        if (!areInstsCompatible(I, J, IsSimpleLoadStore, NonPow2Len,
+            CostSavings, FixedOrder)) continue;
 
         // J is a candidate for merging with I.
         if (!PairableInsts.size() ||
@@ -782,6 +1130,14 @@ namespace {
         }
 
         CandidatePairs.insert(ValuePair(I, J));
+        if (VTTI)
+          CandidatePairCostSavings.insert(ValuePairWithCost(ValuePair(I, J),
+                                                            CostSavings));
+
+        if (FixedOrder == 1)
+          FixedOrderPairs.insert(ValuePair(I, J));
+        else if (FixedOrder == -1)
+          FixedOrderPairs.insert(ValuePair(J, I));
 
         // The next call to this function must start after the last instruction
         // selected during this invocation.
@@ -791,12 +1147,13 @@ namespace {
         }
 
         DEBUG(if (DebugCandidateSelection) dbgs() << "BBV: candidate pair "
-                     << *I << " <-> " << *J << "\n");
+                     << *I << " <-> " << *J << " (cost savings: " <<
+                     CostSavings << ")\n");
 
         // If we have already found too many pairs, break here and this function
         // will be called again starting after the last instruction selected
         // during this invocation.
-        if (PairableInsts.size() >= MaxInsts) {
+        if (PairableInsts.size() >= Config.MaxInsts) {
           ShouldContinue = true;
           break;
         }
@@ -819,47 +1176,91 @@ namespace {
                       std::multimap<Value *, Value *> &CandidatePairs,
                       std::vector<Value *> &PairableInsts,
                       std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                      DenseMap<VPPair, unsigned> &PairConnectionTypes,
                       ValuePair P) {
+    StoreInst *SI, *SJ;
+
     // For each possible pairing for this variable, look at the uses of
     // the first value...
     for (Value::use_iterator I = P.first->use_begin(),
          E = P.first->use_end(); I != E; ++I) {
+      if (isa<LoadInst>(*I)) {
+        // A pair cannot be connected to a load because the load only takes one
+        // operand (the address) and it is a scalar even after vectorization.
+        continue;
+      } else if ((SI = dyn_cast<StoreInst>(*I)) &&
+                 P.first == SI->getPointerOperand()) {
+        // Similarly, a pair cannot be connected to a store through its
+        // pointer operand.
+        continue;
+      }
+
       VPIteratorPair IPairRange = CandidatePairs.equal_range(*I);
 
       // For each use of the first variable, look for uses of the second
       // variable...
       for (Value::use_iterator J = P.second->use_begin(),
            E2 = P.second->use_end(); J != E2; ++J) {
+        if ((SJ = dyn_cast<StoreInst>(*J)) &&
+            P.second == SJ->getPointerOperand())
+          continue;
+
         VPIteratorPair JPairRange = CandidatePairs.equal_range(*J);
 
         // Look for <I, J>:
-        if (isSecondInIteratorPair<Value*>(*J, IPairRange))
-          ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J)));
+        if (isSecondInIteratorPair<Value*>(*J, IPairRange)) {
+          VPPair VP(P, ValuePair(*I, *J));
+          ConnectedPairs.insert(VP);
+          PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionDirect));
+        }
 
         // Look for <J, I>:
-        if (isSecondInIteratorPair<Value*>(*I, JPairRange))
-          ConnectedPairs.insert(VPPair(P, ValuePair(*J, *I)));
+        if (isSecondInIteratorPair<Value*>(*I, JPairRange)) {
+          VPPair VP(P, ValuePair(*J, *I));
+          ConnectedPairs.insert(VP);
+          PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSwap));
+        }
       }
 
-      if (SplatBreaksChain) continue;
+      if (Config.SplatBreaksChain) continue;
       // Look for cases where just the first value in the pair is used by
       // both members of another pair (splatting).
       for (Value::use_iterator J = P.first->use_begin(); J != E; ++J) {
-        if (isSecondInIteratorPair<Value*>(*J, IPairRange))
-          ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J)));
+        if ((SJ = dyn_cast<StoreInst>(*J)) &&
+            P.first == SJ->getPointerOperand())
+          continue;
+
+        if (isSecondInIteratorPair<Value*>(*J, IPairRange)) {
+          VPPair VP(P, ValuePair(*I, *J));
+          ConnectedPairs.insert(VP);
+          PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat));
+        }
       }
     }
 
-    if (SplatBreaksChain) return;
+    if (Config.SplatBreaksChain) return;
     // Look for cases where just the second value in the pair is used by
     // both members of another pair (splatting).
     for (Value::use_iterator I = P.second->use_begin(),
          E = P.second->use_end(); I != E; ++I) {
+      if (isa<LoadInst>(*I))
+        continue;
+      else if ((SI = dyn_cast<StoreInst>(*I)) &&
+               P.second == SI->getPointerOperand())
+        continue;
+
       VPIteratorPair IPairRange = CandidatePairs.equal_range(*I);
 
       for (Value::use_iterator J = P.second->use_begin(); J != E; ++J) {
-        if (isSecondInIteratorPair<Value*>(*J, IPairRange))
-          ConnectedPairs.insert(VPPair(P, ValuePair(*I, *J)));
+        if ((SJ = dyn_cast<StoreInst>(*J)) &&
+            P.second == SJ->getPointerOperand())
+          continue;
+
+        if (isSecondInIteratorPair<Value*>(*J, IPairRange)) {
+          VPPair VP(P, ValuePair(*I, *J));
+          ConnectedPairs.insert(VP);
+          PairConnectionTypes.insert(VPPairWithType(VP, PairConnectionSplat));
+        }
       }
     }
   }
@@ -870,7 +1271,8 @@ namespace {
   void BBVectorize::computeConnectedPairs(
                       std::multimap<Value *, Value *> &CandidatePairs,
                       std::vector<Value *> &PairableInsts,
-                      std::multimap<ValuePair, ValuePair> &ConnectedPairs) {
+                      std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                      DenseMap<VPPair, unsigned> &PairConnectionTypes) {
 
     for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
          PE = PairableInsts.end(); PI != PE; ++PI) {
@@ -879,7 +1281,7 @@ namespace {
       for (std::multimap<Value *, Value *>::iterator P = choiceRange.first;
            P != choiceRange.second; ++P)
         computePairsConnectedTo(CandidatePairs, PairableInsts,
-                                ConnectedPairs, *P);
+                                ConnectedPairs, PairConnectionTypes, *P);
     }
 
     DEBUG(dbgs() << "BBV: found " << ConnectedPairs.size()
@@ -1214,13 +1616,17 @@ namespace {
   // pairs, given the choice of root pairs as an iterator range.
   void BBVectorize::findBestTreeFor(
                       std::multimap<Value *, Value *> &CandidatePairs,
+                      DenseMap<ValuePair, int> &CandidatePairCostSavings,
                       std::vector<Value *> &PairableInsts,
+                      DenseSet<ValuePair> &FixedOrderPairs,
+                      DenseMap<VPPair, unsigned> &PairConnectionTypes,
                       std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                      std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
                       DenseSet<ValuePair> &PairableInstUsers,
                       std::multimap<ValuePair, ValuePair> &PairableInstUserMap,
                       DenseMap<Value *, Value *> &ChosenPairs,
                       DenseSet<ValuePair> &BestTree, size_t &BestMaxDepth,
-                      size_t &BestEffSize, VPIteratorPair ChoiceRange,
+                      int &BestEffSize, VPIteratorPair ChoiceRange,
                       bool UseCycleCheck) {
     for (std::multimap<Value *, Value *>::iterator J = ChoiceRange.first;
          J != ChoiceRange.second; ++J) {
@@ -1270,17 +1676,243 @@ namespace {
                    PairableInstUsers, PairableInstUserMap, ChosenPairs, Tree,
                    PrunedTree, *J, UseCycleCheck);
 
-      size_t EffSize = 0;
-      for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
-           E = PrunedTree.end(); S != E; ++S)
-        EffSize += getDepthFactor(S->first);
+      int EffSize = 0;
+      if (VTTI) {
+        DenseSet<Value *> PrunedTreeInstrs;
+        for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
+             E = PrunedTree.end(); S != E; ++S) {
+          PrunedTreeInstrs.insert(S->first);
+          PrunedTreeInstrs.insert(S->second);
+        }
+
+        // The set of pairs that have already contributed to the total cost.
+        DenseSet<ValuePair> IncomingPairs;
+
+        // The node weights represent the cost savings associated with
+        // fusing the pair of instructions.
+        for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
+             E = PrunedTree.end(); S != E; ++S) {
+          bool FlipOrder = false;
+
+          if (getDepthFactor(S->first)) {
+            int ESContrib = CandidatePairCostSavings.find(*S)->second;
+            DEBUG(if (DebugPairSelection) dbgs() << "\tweight {"
+                   << *S->first << " <-> " << *S->second << "} = " <<
+                   ESContrib << "\n");
+            EffSize += ESContrib;
+          }
+
+          // The edge weights contribute in a negative sense: they represent
+          // the cost of shuffles.
+          VPPIteratorPair IP = ConnectedPairDeps.equal_range(*S);
+          if (IP.first != ConnectedPairDeps.end()) {
+            unsigned NumDepsDirect = 0, NumDepsSwap = 0;
+            for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
+                 Q != IP.second; ++Q) {
+              if (!PrunedTree.count(Q->second))
+                continue;
+              DenseMap<VPPair, unsigned>::iterator R =
+                PairConnectionTypes.find(VPPair(Q->second, Q->first));
+              assert(R != PairConnectionTypes.end() &&
+                     "Cannot find pair connection type");
+              if (R->second == PairConnectionDirect)
+                ++NumDepsDirect;
+              else if (R->second == PairConnectionSwap)
+                ++NumDepsSwap;
+            }
+
+            // If there are more swaps than direct connections, then
+            // the pair order will be flipped during fusion. So the real
+            // number of swaps is the minimum number.
+            FlipOrder = !FixedOrderPairs.count(*S) &&
+              ((NumDepsSwap > NumDepsDirect) ||
+                FixedOrderPairs.count(ValuePair(S->second, S->first)));
+
+            for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
+                 Q != IP.second; ++Q) {
+              if (!PrunedTree.count(Q->second))
+                continue;
+              DenseMap<VPPair, unsigned>::iterator R =
+                PairConnectionTypes.find(VPPair(Q->second, Q->first));
+              assert(R != PairConnectionTypes.end() &&
+                     "Cannot find pair connection type");
+              Type *Ty1 = Q->second.first->getType(),
+                   *Ty2 = Q->second.second->getType();
+              Type *VTy = getVecTypeForPair(Ty1, Ty2);
+              if ((R->second == PairConnectionDirect && FlipOrder) ||
+                  (R->second == PairConnectionSwap && !FlipOrder)  ||
+                  R->second == PairConnectionSplat) {
+                int ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
+                                                   VTy, VTy);
+                DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
+                  *Q->second.first << " <-> " << *Q->second.second <<
+                    "} -> {" <<
+                  *S->first << " <-> " << *S->second << "} = " <<
+                   ESContrib << "\n");
+                EffSize -= ESContrib;
+              }
+            }
+          }
+
+          // Compute the cost of outgoing edges. We assume that edges outgoing
+          // to shuffles, inserts or extracts can be merged, and so contribute
+          // no additional cost.
+          if (!S->first->getType()->isVoidTy()) {
+            Type *Ty1 = S->first->getType(),
+                 *Ty2 = S->second->getType();
+            Type *VTy = getVecTypeForPair(Ty1, Ty2);
+
+            bool NeedsExtraction = false;
+            for (Value::use_iterator I = S->first->use_begin(),
+                 IE = S->first->use_end(); I != IE; ++I) {
+              if (isa<ShuffleVectorInst>(*I) ||
+                  isa<InsertElementInst>(*I) ||
+                  isa<ExtractElementInst>(*I))
+                continue;
+              if (PrunedTreeInstrs.count(*I))
+                continue;
+              NeedsExtraction = true;
+              break;
+            }
+
+            if (NeedsExtraction) {
+              int ESContrib;
+              if (Ty1->isVectorTy())
+                ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
+                                               Ty1, VTy);
+              else
+                ESContrib = (int) VTTI->getVectorInstrCost(
+                                    Instruction::ExtractElement, VTy, 0);
+
+              DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
+                *S->first << "} = " << ESContrib << "\n");
+              EffSize -= ESContrib;
+            }
+
+            NeedsExtraction = false;
+            for (Value::use_iterator I = S->second->use_begin(),
+                 IE = S->second->use_end(); I != IE; ++I) {
+              if (isa<ShuffleVectorInst>(*I) ||
+                  isa<InsertElementInst>(*I) ||
+                  isa<ExtractElementInst>(*I))
+                continue;
+              if (PrunedTreeInstrs.count(*I))
+                continue;
+              NeedsExtraction = true;
+              break;
+            }
+
+            if (NeedsExtraction) {
+              int ESContrib;
+              if (Ty2->isVectorTy())
+                ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
+                                               Ty2, VTy);
+              else
+                ESContrib = (int) VTTI->getVectorInstrCost(
+                                    Instruction::ExtractElement, VTy, 1);
+              DEBUG(if (DebugPairSelection) dbgs() << "\tcost {" <<
+                *S->second << "} = " << ESContrib << "\n");
+              EffSize -= ESContrib;
+            }
+          }
+
+          // Compute the cost of incoming edges.
+          if (!isa<LoadInst>(S->first) && !isa<StoreInst>(S->first)) {
+            Instruction *S1 = cast<Instruction>(S->first),
+                        *S2 = cast<Instruction>(S->second);
+            for (unsigned o = 0; o < S1->getNumOperands(); ++o) {
+              Value *O1 = S1->getOperand(o), *O2 = S2->getOperand(o);
+
+              // Combining constants into vector constants (or small vector
+              // constants into larger ones are assumed free).
+              if (isa<Constant>(O1) && isa<Constant>(O2))
+                continue;
+
+              if (FlipOrder)
+                std::swap(O1, O2);
+
+              ValuePair VP  = ValuePair(O1, O2);
+              ValuePair VPR = ValuePair(O2, O1);
+
+              // Internal edges are not handled here.
+              if (PrunedTree.count(VP) || PrunedTree.count(VPR))
+                continue;
+
+              Type *Ty1 = O1->getType(),
+                   *Ty2 = O2->getType();
+              Type *VTy = getVecTypeForPair(Ty1, Ty2);
+
+              // Combining vector operations of the same type is also assumed
+              // folded with other operations.
+              if (Ty1 == Ty2 &&
+                  (isa<ShuffleVectorInst>(O1) ||
+                   isa<InsertElementInst>(O1) ||
+                   isa<InsertElementInst>(O1)) &&
+                  (isa<ShuffleVectorInst>(O2) ||
+                   isa<InsertElementInst>(O2) ||
+                   isa<InsertElementInst>(O2)))
+                continue;
+
+              int ESContrib;
+              // This pair has already been formed.
+              if (IncomingPairs.count(VP)) {
+                continue;
+              } else if (IncomingPairs.count(VPR)) {
+                ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
+                                               VTy, VTy);
+              } else if (!Ty1->isVectorTy() && !Ty2->isVectorTy()) {
+                ESContrib = (int) VTTI->getVectorInstrCost(
+                                    Instruction::InsertElement, VTy, 0);
+                ESContrib += (int) VTTI->getVectorInstrCost(
+                                     Instruction::InsertElement, VTy, 1);
+              } else if (!Ty1->isVectorTy()) {
+                // O1 needs to be inserted into a vector of size O2, and then
+                // both need to be shuffled together.
+                ESContrib = (int) VTTI->getVectorInstrCost(
+                                    Instruction::InsertElement, Ty2, 0);
+                ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
+                                                VTy, Ty2);
+              } else if (!Ty2->isVectorTy()) {
+                // O2 needs to be inserted into a vector of size O1, and then
+                // both need to be shuffled together.
+                ESContrib = (int) VTTI->getVectorInstrCost(
+                                    Instruction::InsertElement, Ty1, 0);
+                ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
+                                                VTy, Ty1);
+              } else {
+                Type *TyBig = Ty1, *TySmall = Ty2;
+                if (Ty2->getVectorNumElements() > Ty1->getVectorNumElements())
+                  std::swap(TyBig, TySmall);
+
+                ESContrib = (int) getInstrCost(Instruction::ShuffleVector,
+                                               VTy, TyBig);
+                if (TyBig != TySmall)
+                  ESContrib += (int) getInstrCost(Instruction::ShuffleVector,
+                                                  TyBig, TySmall);
+              }
+
+              DEBUG(if (DebugPairSelection) dbgs() << "\tcost {"
+                     << *O1 << " <-> " << *O2 << "} = " <<
+                     ESContrib << "\n");
+              EffSize -= ESContrib;
+              IncomingPairs.insert(VP);
+            }
+          }
+        }
+      } else {
+        for (DenseSet<ValuePair>::iterator S = PrunedTree.begin(),
+             E = PrunedTree.end(); S != E; ++S)
+          EffSize += (int) getDepthFactor(S->first);
+      }
 
       DEBUG(if (DebugPairSelection)
              dbgs() << "BBV: found pruned Tree for pair {"
              << *J->first << " <-> " << *J->second << "} of depth " <<
              MaxDepth << " and size " << PrunedTree.size() <<
             " (effective size: " << EffSize << ")\n");
-      if (MaxDepth >= ReqChainDepth && EffSize > BestEffSize) {
+      if (((VTTI && !UseChainDepthWithTI) ||
+            MaxDepth >= Config.ReqChainDepth) &&
+          EffSize > 0 && EffSize > BestEffSize) {
         BestMaxDepth = MaxDepth;
         BestEffSize = EffSize;
         BestTree = PrunedTree;
@@ -1292,11 +1924,16 @@ namespace {
   // that will be fused into vector instructions.
   void BBVectorize::choosePairs(
                       std::multimap<Value *, Value *> &CandidatePairs,
+                      DenseMap<ValuePair, int> &CandidatePairCostSavings,
                       std::vector<Value *> &PairableInsts,
+                      DenseSet<ValuePair> &FixedOrderPairs,
+                      DenseMap<VPPair, unsigned> &PairConnectionTypes,
                       std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                      std::multimap<ValuePair, ValuePair> &ConnectedPairDeps,
                       DenseSet<ValuePair> &PairableInstUsers,
                       DenseMap<Value *, Value *>& ChosenPairs) {
-    bool UseCycleCheck = CandidatePairs.size() <= MaxCandPairsForCycleCheck;
+    bool UseCycleCheck =
+     CandidatePairs.size() <= Config.MaxCandPairsForCycleCheck;
     std::multimap<ValuePair, ValuePair> PairableInstUserMap;
     for (std::vector<Value *>::iterator I = PairableInsts.begin(),
          E = PairableInsts.end(); I != E; ++I) {
@@ -1307,9 +1944,12 @@ namespace {
       VPIteratorPair ChoiceRange = CandidatePairs.equal_range(*I);
 
       // The best pair to choose and its tree:
-      size_t BestMaxDepth = 0, BestEffSize = 0;
+      size_t BestMaxDepth = 0;
+      int BestEffSize = 0;
       DenseSet<ValuePair> BestTree;
-      findBestTreeFor(CandidatePairs, PairableInsts, ConnectedPairs,
+      findBestTreeFor(CandidatePairs, CandidatePairCostSavings,
+                      PairableInsts, FixedOrderPairs, PairConnectionTypes,
+                      ConnectedPairs, ConnectedPairDeps,
                       PairableInstUsers, PairableInstUserMap, ChosenPairs,
                       BestTree, BestMaxDepth, BestEffSize, ChoiceRange,
                       UseCycleCheck);
@@ -1362,41 +2002,41 @@ namespace {
   // Returns the value that is to be used as the pointer input to the vector
   // instruction that fuses I with J.
   Value *BBVectorize::getReplacementPointerInput(LLVMContext& Context,
-                     Instruction *I, Instruction *J, unsigned o,
-                     bool &FlipMemInputs) {
+                     Instruction *I, Instruction *J, unsigned o) {
     Value *IPtr, *JPtr;
-    unsigned IAlignment, JAlignment;
+    unsigned IAlignment, JAlignment, IAddressSpace, JAddressSpace;
     int64_t OffsetInElmts;
+
+    // Note: the analysis might fail here, that is why the pair order has
+    // been precomputed (OffsetInElmts must be unused here).
     (void) getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
-                          OffsetInElmts);
+                          IAddressSpace, JAddressSpace,
+                          OffsetInElmts, false);
 
     // The pointer value is taken to be the one with the lowest offset.
-    Value *VPtr;
-    if (OffsetInElmts > 0) {
-      VPtr = IPtr;
-    } else {
-      FlipMemInputs = true;
-      VPtr = JPtr;
-    }
+    Value *VPtr = IPtr;
 
-    Type *ArgType = cast<PointerType>(IPtr->getType())->getElementType();
-    Type *VArgType = getVecTypeForPair(ArgType);
+    Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType();
+    Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType();
+    Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
     Type *VArgPtrType = PointerType::get(VArgType,
       cast<PointerType>(IPtr->getType())->getAddressSpace());
     return new BitCastInst(VPtr, VArgPtrType, getReplacementName(I, true, o),
-                        /* insert before */ FlipMemInputs ? J : I);
+                        /* insert before */ I);
   }
 
   void BBVectorize::fillNewShuffleMask(LLVMContext& Context, Instruction *J,
-                     unsigned NumElem, unsigned MaskOffset, unsigned NumInElem,
-                     unsigned IdxOffset, std::vector<Constant*> &Mask) {
-    for (unsigned v = 0; v < NumElem/2; ++v) {
+                     unsigned MaskOffset, unsigned NumInElem,
+                     unsigned NumInElem1, unsigned IdxOffset,
+                     std::vector<Constant*> &Mask) {
+    unsigned NumElem1 = cast<VectorType>(J->getType())->getNumElements();
+    for (unsigned v = 0; v < NumElem1; ++v) {
       int m = cast<ShuffleVectorInst>(J)->getMaskValue(v);
       if (m < 0) {
         Mask[v+MaskOffset] = UndefValue::get(Type::getInt32Ty(Context));
       } else {
         unsigned mm = m + (int) IdxOffset;
-        if (m >= (int) NumInElem)
+        if (m >= (int) NumInElem1)
           mm += (int) NumInElem;
 
         Mask[v+MaskOffset] =
@@ -1412,8 +2052,11 @@ namespace {
     // This is the shuffle mask. We need to append the second
     // mask to the first, and the numbers need to be adjusted.
 
-    Type *ArgType = I->getType();
-    Type *VArgType = getVecTypeForPair(ArgType);
+    Type *ArgTypeI = I->getType();
+    Type *ArgTypeJ = J->getType();
+    Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
+
+    unsigned NumElemI = cast<VectorType>(ArgTypeI)->getNumElements();
 
     // Get the total number of elements in the fused vector type.
     // By definition, this must equal the number of elements in
@@ -1421,106 +2064,422 @@ namespace {
     unsigned NumElem = cast<VectorType>(VArgType)->getNumElements();
     std::vector<Constant*> Mask(NumElem);
 
-    Type *OpType = I->getOperand(0)->getType();
-    unsigned NumInElem = cast<VectorType>(OpType)->getNumElements();
+    Type *OpTypeI = I->getOperand(0)->getType();
+    unsigned NumInElemI = cast<VectorType>(OpTypeI)->getNumElements();
+    Type *OpTypeJ = J->getOperand(0)->getType();
+    unsigned NumInElemJ = cast<VectorType>(OpTypeJ)->getNumElements();
+
+    // The fused vector will be:
+    // -----------------------------------------------------
+    // | NumInElemI | NumInElemJ | NumInElemI | NumInElemJ |
+    // -----------------------------------------------------
+    // from which we'll extract NumElem total elements (where the first NumElemI
+    // of them come from the mask in I and the remainder come from the mask
+    // in J.
 
     // For the mask from the first pair...
-    fillNewShuffleMask(Context, I, NumElem, 0, NumInElem, 0, Mask);
+    fillNewShuffleMask(Context, I, 0,        NumInElemJ, NumInElemI,
+                       0,          Mask);
 
     // For the mask from the second pair...
-    fillNewShuffleMask(Context, J, NumElem, NumElem/2, NumInElem, NumInElem,
-                       Mask);
+    fillNewShuffleMask(Context, J, NumElemI, NumInElemI, NumInElemJ,
+                       NumInElemI, Mask);
 
     return ConstantVector::get(Mask);
   }
 
+  bool BBVectorize::expandIEChain(LLVMContext& Context, Instruction *I,
+                                  Instruction *J, unsigned o, Value *&LOp,
+                                  unsigned numElemL,
+                                  Type *ArgTypeL, Type *ArgTypeH,
+                                  bool IBeforeJ, unsigned IdxOff) {
+    bool ExpandedIEChain = false;
+    if (InsertElementInst *LIE = dyn_cast<InsertElementInst>(LOp)) {
+      // If we have a pure insertelement chain, then this can be rewritten
+      // into a chain that directly builds the larger type.
+      bool PureChain = true;
+      InsertElementInst *LIENext = LIE;
+      do {
+        if (!isa<UndefValue>(LIENext->getOperand(0)) &&
+            !isa<InsertElementInst>(LIENext->getOperand(0))) {
+          PureChain = false;
+          break;
+        }
+      } while ((LIENext =
+                 dyn_cast<InsertElementInst>(LIENext->getOperand(0))));
+
+      if (PureChain) {
+        SmallVector<Value *, 8> VectElemts(numElemL,
+          UndefValue::get(ArgTypeL->getScalarType()));
+        InsertElementInst *LIENext = LIE;
+        do {
+          unsigned Idx =
+            cast<ConstantInt>(LIENext->getOperand(2))->getSExtValue();
+          VectElemts[Idx] = LIENext->getOperand(1);
+        } while ((LIENext =
+                   dyn_cast<InsertElementInst>(LIENext->getOperand(0))));
+
+        LIENext = 0;
+        Value *LIEPrev = UndefValue::get(ArgTypeH);
+        for (unsigned i = 0; i < numElemL; ++i) {
+          if (isa<UndefValue>(VectElemts[i])) continue;
+          LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i],
+                             ConstantInt::get(Type::getInt32Ty(Context),
+                                              i + IdxOff),
+                             getReplacementName(IBeforeJ ? I : J,
+                                                true, o, i+1));
+          LIENext->insertBefore(IBeforeJ ? J : I);
+          LIEPrev = LIENext;
+        }
+
+        LOp = LIENext ? (Value*) LIENext : UndefValue::get(ArgTypeH);
+        ExpandedIEChain = true;
+      }
+    }
+
+    return ExpandedIEChain;
+  }
+
   // Returns the value to be used as the specified operand of the vector
   // instruction that fuses I with J.
   Value *BBVectorize::getReplacementInput(LLVMContext& Context, Instruction *I,
-                     Instruction *J, unsigned o, bool FlipMemInputs) {
+                     Instruction *J, unsigned o, bool IBeforeJ) {
     Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
     Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1);
 
-      // Compute the fused vector type for this operand
-    Type *ArgType = I->getOperand(o)->getType();
-    VectorType *VArgType = getVecTypeForPair(ArgType);
+    // Compute the fused vector type for this operand
+    Type *ArgTypeI = I->getOperand(o)->getType();
+    Type *ArgTypeJ = J->getOperand(o)->getType();
+    VectorType *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
 
     Instruction *L = I, *H = J;
-    if (FlipMemInputs) {
-      L = J;
-      H = I;
+    Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ;
+
+    unsigned numElemL;
+    if (ArgTypeL->isVectorTy())
+      numElemL = cast<VectorType>(ArgTypeL)->getNumElements();
+    else
+      numElemL = 1;
+
+    unsigned numElemH;
+    if (ArgTypeH->isVectorTy())
+      numElemH = cast<VectorType>(ArgTypeH)->getNumElements();
+    else
+      numElemH = 1;
+
+    Value *LOp = L->getOperand(o);
+    Value *HOp = H->getOperand(o);
+    unsigned numElem = VArgType->getNumElements();
+
+    // First, we check if we can reuse the "original" vector outputs (if these
+    // exist). We might need a shuffle.
+    ExtractElementInst *LEE = dyn_cast<ExtractElementInst>(LOp);
+    ExtractElementInst *HEE = dyn_cast<ExtractElementInst>(HOp);
+    ShuffleVectorInst *LSV = dyn_cast<ShuffleVectorInst>(LOp);
+    ShuffleVectorInst *HSV = dyn_cast<ShuffleVectorInst>(HOp);
+
+    // FIXME: If we're fusing shuffle instructions, then we can't apply this
+    // optimization. The input vectors to the shuffle might be a different
+    // length from the shuffle outputs. Unfortunately, the replacement
+    // shuffle mask has already been formed, and the mask entries are sensitive
+    // to the sizes of the inputs.
+    bool IsSizeChangeShuffle =
+      isa<ShuffleVectorInst>(L) &&
+        (LOp->getType() != L->getType() || HOp->getType() != H->getType());
+
+    if ((LEE || LSV) && (HEE || HSV) && !IsSizeChangeShuffle) {
+      // We can have at most two unique vector inputs.
+      bool CanUseInputs = true;
+      Value *I1, *I2 = 0;
+      if (LEE) {
+        I1 = LEE->getOperand(0);
+      } else {
+        I1 = LSV->getOperand(0);
+        I2 = LSV->getOperand(1);
+        if (I2 == I1 || isa<UndefValue>(I2))
+          I2 = 0;
+      }
+  
+      if (HEE) {
+        Value *I3 = HEE->getOperand(0);
+        if (!I2 && I3 != I1)
+          I2 = I3;
+        else if (I3 != I1 && I3 != I2)
+          CanUseInputs = false;
+      } else {
+        Value *I3 = HSV->getOperand(0);
+        if (!I2 && I3 != I1)
+          I2 = I3;
+        else if (I3 != I1 && I3 != I2)
+          CanUseInputs = false;
+
+        if (CanUseInputs) {
+          Value *I4 = HSV->getOperand(1);
+          if (!isa<UndefValue>(I4)) {
+            if (!I2 && I4 != I1)
+              I2 = I4;
+            else if (I4 != I1 && I4 != I2)
+              CanUseInputs = false;
+          }
+        }
+      }
+
+      if (CanUseInputs) {
+        unsigned LOpElem =
+          cast<VectorType>(cast<Instruction>(LOp)->getOperand(0)->getType())
+            ->getNumElements();
+        unsigned HOpElem =
+          cast<VectorType>(cast<Instruction>(HOp)->getOperand(0)->getType())
+            ->getNumElements();
+
+        // We have one or two input vectors. We need to map each index of the
+        // operands to the index of the original vector.
+        SmallVector<std::pair<int, int>, 8>  II(numElem);
+        for (unsigned i = 0; i < numElemL; ++i) {
+          int Idx, INum;
+          if (LEE) {
+            Idx =
+              cast<ConstantInt>(LEE->getOperand(1))->getSExtValue();
+            INum = LEE->getOperand(0) == I1 ? 0 : 1;
+          } else {
+            Idx = LSV->getMaskValue(i);
+            if (Idx < (int) LOpElem) {
+              INum = LSV->getOperand(0) == I1 ? 0 : 1;
+            } else {
+              Idx -= LOpElem;
+              INum = LSV->getOperand(1) == I1 ? 0 : 1;
+            }
+          }
+
+          II[i] = std::pair<int, int>(Idx, INum);
+        }
+        for (unsigned i = 0; i < numElemH; ++i) {
+          int Idx, INum;
+          if (HEE) {
+            Idx =
+              cast<ConstantInt>(HEE->getOperand(1))->getSExtValue();
+            INum = HEE->getOperand(0) == I1 ? 0 : 1;
+          } else {
+            Idx = HSV->getMaskValue(i);
+            if (Idx < (int) HOpElem) {
+              INum = HSV->getOperand(0) == I1 ? 0 : 1;
+            } else {
+              Idx -= HOpElem;
+              INum = HSV->getOperand(1) == I1 ? 0 : 1;
+            }
+          }
+
+          II[i + numElemL] = std::pair<int, int>(Idx, INum);
+        }
+
+        // We now have an array which tells us from which index of which
+        // input vector each element of the operand comes.
+        VectorType *I1T = cast<VectorType>(I1->getType());
+        unsigned I1Elem = I1T->getNumElements();
+
+        if (!I2) {
+          // In this case there is only one underlying vector input. Check for
+          // the trivial case where we can use the input directly.
+          if (I1Elem == numElem) {
+            bool ElemInOrder = true;
+            for (unsigned i = 0; i < numElem; ++i) {
+              if (II[i].first != (int) i && II[i].first != -1) {
+                ElemInOrder = false;
+                break;
+              }
+            }
+
+            if (ElemInOrder)
+              return I1;
+          }
+
+          // A shuffle is needed.
+          std::vector<Constant *> Mask(numElem);
+          for (unsigned i = 0; i < numElem; ++i) {
+            int Idx = II[i].first;
+            if (Idx == -1)
+              Mask[i] = UndefValue::get(Type::getInt32Ty(Context));
+            else
+              Mask[i] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
+          }
+
+          Instruction *S =
+            new ShuffleVectorInst(I1, UndefValue::get(I1T),
+                                  ConstantVector::get(Mask),
+                                  getReplacementName(IBeforeJ ? I : J,
+                                                     true, o));
+          S->insertBefore(IBeforeJ ? J : I);
+          return S;
+        }
+
+        VectorType *I2T = cast<VectorType>(I2->getType());
+        unsigned I2Elem = I2T->getNumElements();
+
+        // This input comes from two distinct vectors. The first step is to
+        // make sure that both vectors are the same length. If not, the
+        // smaller one will need to grow before they can be shuffled together.
+        if (I1Elem < I2Elem) {
+          std::vector<Constant *> Mask(I2Elem);
+          unsigned v = 0;
+          for (; v < I1Elem; ++v)
+            Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
+          for (; v < I2Elem; ++v)
+            Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
+
+          Instruction *NewI1 =
+            new ShuffleVectorInst(I1, UndefValue::get(I1T),
+                                  ConstantVector::get(Mask),
+                                  getReplacementName(IBeforeJ ? I : J,
+                                                     true, o, 1));
+          NewI1->insertBefore(IBeforeJ ? J : I);
+          I1 = NewI1;
+          I1T = I2T;
+          I1Elem = I2Elem;
+        } else if (I1Elem > I2Elem) {
+          std::vector<Constant *> Mask(I1Elem);
+          unsigned v = 0;
+          for (; v < I2Elem; ++v)
+            Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
+          for (; v < I1Elem; ++v)
+            Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
+
+          Instruction *NewI2 =
+            new ShuffleVectorInst(I2, UndefValue::get(I2T),
+                                  ConstantVector::get(Mask),
+                                  getReplacementName(IBeforeJ ? I : J,
+                                                     true, o, 1));
+          NewI2->insertBefore(IBeforeJ ? J : I);
+          I2 = NewI2;
+          I2T = I1T;
+          I2Elem = I1Elem;
+        }
+
+        // Now that both I1 and I2 are the same length we can shuffle them
+        // together (and use the result).
+        std::vector<Constant *> Mask(numElem);
+        for (unsigned v = 0; v < numElem; ++v) {
+          if (II[v].first == -1) {
+            Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
+          } else {
+            int Idx = II[v].first + II[v].second * I1Elem;
+            Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
+          }
+        }
+
+        Instruction *NewOp =
+          new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask),
+                                getReplacementName(IBeforeJ ? I : J, true, o));
+        NewOp->insertBefore(IBeforeJ ? J : I);
+        return NewOp;
+      }
+    }
+
+    Type *ArgType = ArgTypeL;
+    if (numElemL < numElemH) {
+      if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH,
+                                         ArgTypeL, VArgType, IBeforeJ, 1)) {
+        // This is another short-circuit case: we're combining a scalar into
+        // a vector that is formed by an IE chain. We've just expanded the IE
+        // chain, now insert the scalar and we're done.
+
+        Instruction *S = InsertElementInst::Create(HOp, LOp, CV0,
+                           getReplacementName(IBeforeJ ? I : J, true, o));
+        S->insertBefore(IBeforeJ ? J : I);
+        return S;
+      } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL,
+                                ArgTypeH, IBeforeJ)) {
+        // The two vector inputs to the shuffle must be the same length,
+        // so extend the smaller vector to be the same length as the larger one.
+        Instruction *NLOp;
+        if (numElemL > 1) {
+  
+          std::vector<Constant *> Mask(numElemH);
+          unsigned v = 0;
+          for (; v < numElemL; ++v)
+            Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
+          for (; v < numElemH; ++v)
+            Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
+    
+          NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL),
+                                       ConstantVector::get(Mask),
+                                       getReplacementName(IBeforeJ ? I : J,
+                                                          true, o, 1));
+        } else {
+          NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0,
+                                           getReplacementName(IBeforeJ ? I : J,
+                                                              true, o, 1));
+        }
+  
+        NLOp->insertBefore(IBeforeJ ? J : I);
+        LOp = NLOp;
+      }
+
+      ArgType = ArgTypeH;
+    } else if (numElemL > numElemH) {
+      if (numElemH == 1 && expandIEChain(Context, I, J, o, LOp, numElemL,
+                                         ArgTypeH, VArgType, IBeforeJ)) {
+        Instruction *S =
+          InsertElementInst::Create(LOp, HOp, 
+                                    ConstantInt::get(Type::getInt32Ty(Context),
+                                                     numElemL),
+                                    getReplacementName(IBeforeJ ? I : J,
+                                                       true, o));
+        S->insertBefore(IBeforeJ ? J : I);
+        return S;
+      } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH,
+                                ArgTypeL, IBeforeJ)) {
+        Instruction *NHOp;
+        if (numElemH > 1) {
+          std::vector<Constant *> Mask(numElemL);
+          unsigned v = 0;
+          for (; v < numElemH; ++v)
+            Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
+          for (; v < numElemL; ++v)
+            Mask[v] = UndefValue::get(Type::getInt32Ty(Context));
+    
+          NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH),
+                                       ConstantVector::get(Mask),
+                                       getReplacementName(IBeforeJ ? I : J,
+                                                          true, o, 1));
+        } else {
+          NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0,
+                                           getReplacementName(IBeforeJ ? I : J,
+                                                              true, o, 1));
+        }
+  
+        NHOp->insertBefore(IBeforeJ ? J : I);
+        HOp = NHOp;
+      }
     }
 
     if (ArgType->isVectorTy()) {
       unsigned numElem = cast<VectorType>(VArgType)->getNumElements();
       std::vector<Constant*> Mask(numElem);
-      for (unsigned v = 0; v < numElem; ++v)
-        Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
-
-      Instruction *BV = new ShuffleVectorInst(L->getOperand(o),
-                                              H->getOperand(o),
-                                              ConstantVector::get(Mask),
-                                              getReplacementName(I, true, o));
-      BV->insertBefore(J);
-      return BV;
-    }
-
-    // If these two inputs are the output of another vector instruction,
-    // then we should use that output directly. It might be necessary to
-    // permute it first. [When pairings are fused recursively, you can
-    // end up with cases where a large vector is decomposed into scalars
-    // using extractelement instructions, then built into size-2
-    // vectors using insertelement and the into larger vectors using
-    // shuffles. InstCombine does not simplify all of these cases well,
-    // and so we make sure that shuffles are generated here when possible.
-    ExtractElementInst *LEE
-      = dyn_cast<ExtractElementInst>(L->getOperand(o));
-    ExtractElementInst *HEE
-      = dyn_cast<ExtractElementInst>(H->getOperand(o));
-
-    if (LEE && HEE &&
-        LEE->getOperand(0)->getType() == HEE->getOperand(0)->getType()) {
-      VectorType *EEType = cast<VectorType>(LEE->getOperand(0)->getType());
-      unsigned LowIndx = cast<ConstantInt>(LEE->getOperand(1))->getZExtValue();
-      unsigned HighIndx = cast<ConstantInt>(HEE->getOperand(1))->getZExtValue();
-      if (LEE->getOperand(0) == HEE->getOperand(0)) {
-        if (LowIndx == 0 && HighIndx == 1)
-          return LEE->getOperand(0);
-
-        std::vector<Constant*> Mask(2);
-        Mask[0] = ConstantInt::get(Type::getInt32Ty(Context), LowIndx);
-        Mask[1] = ConstantInt::get(Type::getInt32Ty(Context), HighIndx);
-
-        Instruction *BV = new ShuffleVectorInst(LEE->getOperand(0),
-                                          UndefValue::get(EEType),
-                                          ConstantVector::get(Mask),
-                                          getReplacementName(I, true, o));
-        BV->insertBefore(J);
-        return BV;
+      for (unsigned v = 0; v < numElem; ++v) {
+        unsigned Idx = v;
+        // If the low vector was expanded, we need to skip the extra
+        // undefined entries.
+        if (v >= numElemL && numElemH > numElemL)
+          Idx += (numElemH - numElemL);
+        Mask[v] = ConstantInt::get(Type::getInt32Ty(Context), Idx);
       }
 
-      std::vector<Constant*> Mask(2);
-      HighIndx += EEType->getNumElements();
-      Mask[0] = ConstantInt::get(Type::getInt32Ty(Context), LowIndx);
-      Mask[1] = ConstantInt::get(Type::getInt32Ty(Context), HighIndx);
-
-      Instruction *BV = new ShuffleVectorInst(LEE->getOperand(0),
-                                          HEE->getOperand(0),
-                                          ConstantVector::get(Mask),
-                                          getReplacementName(I, true, o));
-      BV->insertBefore(J);
+      Instruction *BV = new ShuffleVectorInst(LOp, HOp,
+                          ConstantVector::get(Mask),
+                          getReplacementName(IBeforeJ ? I : J, true, o));
+      BV->insertBefore(IBeforeJ ? J : I);
       return BV;
     }
 
     Instruction *BV1 = InsertElementInst::Create(
-                                          UndefValue::get(VArgType),
-                                          L->getOperand(o), CV0,
-                                          getReplacementName(I, true, o, 1));
-    BV1->insertBefore(I);
-    Instruction *BV2 = InsertElementInst::Create(BV1, H->getOperand(o),
-                                          CV1,
-                                          getReplacementName(I, true, o, 2));
-    BV2->insertBefore(J);
+                                          UndefValue::get(VArgType), LOp, CV0,
+                                          getReplacementName(IBeforeJ ? I : J,
+                                                             true, o, 1));
+    BV1->insertBefore(IBeforeJ ? J : I);
+    Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1,
+                                          getReplacementName(IBeforeJ ? I : J,
+                                                             true, o, 2));
+    BV2->insertBefore(IBeforeJ ? J : I);
     return BV2;
   }
 
@@ -1529,8 +2488,7 @@ namespace {
   void BBVectorize::getReplacementInputsForPair(LLVMContext& Context,
                      Instruction *I, Instruction *J,
                      SmallVector<Value *, 3> &ReplacedOperands,
-                     bool &FlipMemInputs) {
-    FlipMemInputs = false;
+                     bool IBeforeJ) {
     unsigned NumOperands = I->getNumOperands();
 
     for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) {
@@ -1539,20 +2497,19 @@ namespace {
 
       if (isa<LoadInst>(I) || (o == 1 && isa<StoreInst>(I))) {
         // This is the pointer for a load/store instruction.
-        ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o,
-                                FlipMemInputs);
+        ReplacedOperands[o] = getReplacementPointerInput(Context, I, J, o);
         continue;
       } else if (isa<CallInst>(I)) {
         Function *F = cast<CallInst>(I)->getCalledFunction();
         unsigned IID = F->getIntrinsicID();
         if (o == NumOperands-1) {
           BasicBlock &BB = *I->getParent();
-  
+
           Module *M = BB.getParent()->getParent();
-          Type *ArgType = I->getType();
-          Type *VArgType = getVecTypeForPair(ArgType);
-  
-          // FIXME: is it safe to do this here?
+          Type *ArgTypeI = I->getType();
+          Type *ArgTypeJ = J->getType();
+          Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
+
           ReplacedOperands[o] = Intrinsic::getDeclaration(M,
             (Intrinsic::ID) IID, VArgType);
           continue;
@@ -1568,8 +2525,7 @@ namespace {
         continue;
       }
 
-      ReplacedOperands[o] =
-        getReplacementInput(Context, I, J, o, FlipMemInputs);
+      ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ);
     }
   }
 
@@ -1580,38 +2536,57 @@ namespace {
   void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
                      Instruction *J, Instruction *K,
                      Instruction *&InsertionPt,
-                     Instruction *&K1, Instruction *&K2,
-                     bool &FlipMemInputs) {
-    Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
-    Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), 1);
-
+                     Instruction *&K1, Instruction *&K2) {
     if (isa<StoreInst>(I)) {
       AA->replaceWithNewValue(I, K);
       AA->replaceWithNewValue(J, K);
     } else {
       Type *IType = I->getType();
-      Type *VType = getVecTypeForPair(IType);
+      Type *JType = J->getType();
+
+      VectorType *VType = getVecTypeForPair(IType, JType);
+      unsigned numElem = VType->getNumElements();
+
+      unsigned numElemI, numElemJ;
+      if (IType->isVectorTy())
+        numElemI = cast<VectorType>(IType)->getNumElements();
+      else
+        numElemI = 1;
+
+      if (JType->isVectorTy())
+        numElemJ = cast<VectorType>(JType)->getNumElements();
+      else
+        numElemJ = 1;
 
       if (IType->isVectorTy()) {
-          unsigned numElem = cast<VectorType>(IType)->getNumElements();
-          std::vector<Constant*> Mask1(numElem), Mask2(numElem);
-          for (unsigned v = 0; v < numElem; ++v) {
-            Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
-            Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElem+v);
-          }
+        std::vector<Constant*> Mask1(numElemI), Mask2(numElemI);
+        for (unsigned v = 0; v < numElemI; ++v) {
+          Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
+          Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemJ+v);
+        }
 
-          K1 = new ShuffleVectorInst(K, UndefValue::get(VType),
-                                       ConstantVector::get(
-                                         FlipMemInputs ? Mask2 : Mask1),
-                                       getReplacementName(K, false, 1));
-          K2 = new ShuffleVectorInst(K, UndefValue::get(VType),
-                                       ConstantVector::get(
-                                         FlipMemInputs ? Mask1 : Mask2),
-                                       getReplacementName(K, false, 2));
+        K1 = new ShuffleVectorInst(K, UndefValue::get(VType),
+                                   ConstantVector::get( Mask1),
+                                   getReplacementName(K, false, 1));
       } else {
-        K1 = ExtractElementInst::Create(K, FlipMemInputs ? CV1 : CV0,
+        Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
+        K1 = ExtractElementInst::Create(K, CV0,
                                           getReplacementName(K, false, 1));
-        K2 = ExtractElementInst::Create(K, FlipMemInputs ? CV0 : CV1,
+      }
+
+      if (JType->isVectorTy()) {
+        std::vector<Constant*> Mask1(numElemJ), Mask2(numElemJ);
+        for (unsigned v = 0; v < numElemJ; ++v) {
+          Mask1[v] = ConstantInt::get(Type::getInt32Ty(Context), v);
+          Mask2[v] = ConstantInt::get(Type::getInt32Ty(Context), numElemI+v);
+        }
+
+        K2 = new ShuffleVectorInst(K, UndefValue::get(VType),
+                                   ConstantVector::get( Mask2),
+                                   getReplacementName(K, false, 2));
+      } else {
+        Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1);
+        K2 = ExtractElementInst::Create(K, CV1,
                                           getReplacementName(K, false, 2));
       }
 
@@ -1711,6 +2686,31 @@ namespace {
     }
   }
 
+  // When the first instruction in each pair is cloned, it will inherit its
+  // parent's metadata. This metadata must be combined with that of the other
+  // instruction in a safe way.
+  void BBVectorize::combineMetadata(Instruction *K, const Instruction *J) {
+    SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata;
+    K->getAllMetadataOtherThanDebugLoc(Metadata);
+    for (unsigned i = 0, n = Metadata.size(); i < n; ++i) {
+      unsigned Kind = Metadata[i].first;
+      MDNode *JMD = J->getMetadata(Kind);
+      MDNode *KMD = Metadata[i].second;
+
+      switch (Kind) {
+      default:
+        K->setMetadata(Kind, 0); // Remove unknown metadata
+        break;
+      case LLVMContext::MD_tbaa:
+        K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD));
+        break;
+      case LLVMContext::MD_fpmath:
+        K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD));
+        break;
+      }
+    }
+  }
+
   // This function fuses the chosen instruction pairs into vector instructions,
   // taking care preserve any needed scalar outputs and, then, it reorders the
   // remaining instructions as needed (users of the first member of the pair
@@ -1719,18 +2719,21 @@ namespace {
   // second member).
   void BBVectorize::fuseChosenPairs(BasicBlock &BB,
                      std::vector<Value *> &PairableInsts,
-                     DenseMap<Value *, Value *> &ChosenPairs) {
+                     DenseMap<Value *, Value *> &ChosenPairs,
+                     DenseSet<ValuePair> &FixedOrderPairs,
+                     DenseMap<VPPair, unsigned> &PairConnectionTypes,
+                     std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                     std::multimap<ValuePair, ValuePair> &ConnectedPairDeps) {
     LLVMContext& Context = BB.getContext();
 
     // During the vectorization process, the order of the pairs to be fused
     // could be flipped. So we'll add each pair, flipped, into the ChosenPairs
     // list. After a pair is fused, the flipped pair is removed from the list.
-    std::vector<ValuePair> FlippedPairs;
-    FlippedPairs.reserve(ChosenPairs.size());
+    DenseSet<ValuePair> FlippedPairs;
     for (DenseMap<Value *, Value *>::iterator P = ChosenPairs.begin(),
          E = ChosenPairs.end(); P != E; ++P)
-      FlippedPairs.push_back(ValuePair(P->second, P->first));
-    for (std::vector<ValuePair>::iterator P = FlippedPairs.begin(),
+      FlippedPairs.insert(ValuePair(P->second, P->first));
+    for (DenseSet<ValuePair>::iterator P = FlippedPairs.begin(),
          E = FlippedPairs.end(); P != E; ++P)
       ChosenPairs.insert(*P);
 
@@ -1776,39 +2779,91 @@ namespace {
         continue;
       }
 
-      bool FlipMemInputs;
+      // If the pair must have the other order, then flip it.
+      bool FlipPairOrder = FixedOrderPairs.count(ValuePair(J, I));
+      if (!FlipPairOrder && !FixedOrderPairs.count(ValuePair(I, J))) {
+        // This pair does not have a fixed order, and so we might want to
+        // flip it if that will yield fewer shuffles. We count the number
+        // of dependencies connected via swaps, and those directly connected,
+        // and flip the order if the number of swaps is greater.
+        bool OrigOrder = true;
+        VPPIteratorPair IP = ConnectedPairDeps.equal_range(ValuePair(I, J));
+        if (IP.first == ConnectedPairDeps.end()) {
+          IP = ConnectedPairDeps.equal_range(ValuePair(J, I));
+          OrigOrder = false;
+        }
+
+        if (IP.first != ConnectedPairDeps.end()) {
+          unsigned NumDepsDirect = 0, NumDepsSwap = 0;
+          for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
+               Q != IP.second; ++Q) {
+            DenseMap<VPPair, unsigned>::iterator R =
+              PairConnectionTypes.find(VPPair(Q->second, Q->first));
+            assert(R != PairConnectionTypes.end() &&
+                   "Cannot find pair connection type");
+            if (R->second == PairConnectionDirect)
+              ++NumDepsDirect;
+            else if (R->second == PairConnectionSwap)
+              ++NumDepsSwap;
+          }
+
+          if (!OrigOrder)
+            std::swap(NumDepsDirect, NumDepsSwap);
+
+          if (NumDepsSwap > NumDepsDirect) {
+            FlipPairOrder = true;
+            DEBUG(dbgs() << "BBV: reordering pair: " << *I <<
+                            " <-> " << *J << "\n");
+          }
+        }
+      }
+
+      Instruction *L = I, *H = J;
+      if (FlipPairOrder)
+        std::swap(H, L);
+
+      // If the pair being fused uses the opposite order from that in the pair
+      // connection map, then we need to flip the types.
+      VPPIteratorPair IP = ConnectedPairs.equal_range(ValuePair(H, L));
+      for (std::multimap<ValuePair, ValuePair>::iterator Q = IP.first;
+           Q != IP.second; ++Q) {
+        DenseMap<VPPair, unsigned>::iterator R = PairConnectionTypes.find(*Q);
+        assert(R != PairConnectionTypes.end() &&
+               "Cannot find pair connection type");
+        if (R->second == PairConnectionDirect)
+          R->second = PairConnectionSwap;
+        else if (R->second == PairConnectionSwap)
+          R->second = PairConnectionDirect;
+      }
+
+      bool LBeforeH = !FlipPairOrder;
       unsigned NumOperands = I->getNumOperands();
       SmallVector<Value *, 3> ReplacedOperands(NumOperands);
-      getReplacementInputsForPair(Context, I, J, ReplacedOperands,
-        FlipMemInputs);
+      getReplacementInputsForPair(Context, L, H, ReplacedOperands,
+                                  LBeforeH);
 
       // Make a copy of the original operation, change its type to the vector
       // type and replace its operands with the vector operands.
-      Instruction *K = I->clone();
-      if (I->hasName()) K->takeName(I);
+      Instruction *K = L->clone();
+      if (L->hasName())
+        K->takeName(L);
+      else if (H->hasName())
+        K->takeName(H);
 
       if (!isa<StoreInst>(K))
-        K->mutateType(getVecTypeForPair(I->getType()));
+        K->mutateType(getVecTypeForPair(L->getType(), H->getType()));
+
+      combineMetadata(K, H);
 
       for (unsigned o = 0; o < NumOperands; ++o)
         K->setOperand(o, ReplacedOperands[o]);
 
-      // If we've flipped the memory inputs, make sure that we take the correct
-      // alignment.
-      if (FlipMemInputs) {
-        if (isa<StoreInst>(K))
-          cast<StoreInst>(K)->setAlignment(cast<StoreInst>(J)->getAlignment());
-        else
-          cast<LoadInst>(K)->setAlignment(cast<LoadInst>(J)->getAlignment());
-      }
-
       K->insertAfter(J);
 
       // Instruction insertion point:
       Instruction *InsertionPt = K;
       Instruction *K1 = 0, *K2 = 0;
-      replaceOutputsOfPair(Context, I, J, K, InsertionPt, K1, K2,
-        FlipMemInputs);
+      replaceOutputsOfPair(Context, L, H, K, InsertionPt, K1, K2);
 
       // The use tree of the first original instruction must be moved to after
       // the location of the second instruction. The entire use tree of the
@@ -1818,10 +2873,10 @@ namespace {
       moveUsesOfIAfterJ(BB, LoadMoveSet, InsertionPt, I, J);
 
       if (!isa<StoreInst>(I)) {
-        I->replaceAllUsesWith(K1);
-        J->replaceAllUsesWith(K2);
-        AA->replaceWithNewValue(I, K1);
-        AA->replaceWithNewValue(J, K2);
+        L->replaceAllUsesWith(K1);
+        H->replaceAllUsesWith(K2);
+        AA->replaceWithNewValue(L, K1);
+        AA->replaceWithNewValue(H, K2);
       }
 
       // Instructions that may read from memory may be in the load move set.
@@ -1854,6 +2909,9 @@ namespace {
       SE->forgetValue(J);
       I->eraseFromParent();
       J->eraseFromParent();
+
+      DEBUG(if (PrintAfterEveryPair) dbgs() << "BBV: block is now: \n" <<
+                                               BB << "\n");
     }
 
     DEBUG(dbgs() << "BBV: final: \n" << BB << "\n");
@@ -1864,14 +2922,42 @@ char BBVectorize::ID = 0;
 static const char bb_vectorize_name[] = "Basic-Block Vectorization";
 INITIALIZE_PASS_BEGIN(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
 INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
 INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
 
-BasicBlockPass *llvm::createBBVectorizePass() {
-  return new BBVectorize();
+BasicBlockPass *llvm::createBBVectorizePass(const VectorizeConfig &C) {
+  return new BBVectorize(C);
 }
 
-bool llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB) {
-  BBVectorize BBVectorizer(P);
+bool
+llvm::vectorizeBasicBlock(Pass *P, BasicBlock &BB, const VectorizeConfig &C) {
+  BBVectorize BBVectorizer(P, C);
   return BBVectorizer.vectorizeBB(BB);
 }
+
+//===----------------------------------------------------------------------===//
+VectorizeConfig::VectorizeConfig() {
+  VectorBits = ::VectorBits;
+  VectorizeBools = !::NoBools;
+  VectorizeInts = !::NoInts;
+  VectorizeFloats = !::NoFloats;
+  VectorizePointers = !::NoPointers;
+  VectorizeCasts = !::NoCasts;
+  VectorizeMath = !::NoMath;
+  VectorizeFMA = !::NoFMA;
+  VectorizeSelect = !::NoSelect;
+  VectorizeCmp = !::NoCmp;
+  VectorizeGEP = !::NoGEP;
+  VectorizeMemOps = !::NoMemOps;
+  AlignedOnly = ::AlignedOnly;
+  ReqChainDepth= ::ReqChainDepth;
+  SearchLimit = ::SearchLimit;
+  MaxCandPairsForCycleCheck = ::MaxCandPairsForCycleCheck;
+  SplatBreaksChain = ::SplatBreaksChain;
+  MaxInsts = ::MaxInsts;
+  MaxIter = ::MaxIter;
+  Pow2LenOnly = ::Pow2LenOnly;
+  NoMemOpBoost = ::NoMemOpBoost;
+  FastDep = ::FastDep;
+}