Merge remote-tracking branch 'upstream/master' into merge-llvm

Conflicts:
	lib/CodeGen/AsmPrinter/AsmPrinter.cpp
	lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp
	lib/MC/MCAssembler.cpp
	lib/Support/Atomic.cpp
	lib/Support/Memory.cpp
	lib/Target/ARM/ARMJITInfo.cpp

Change-Id: Ib339baf88df5b04870c8df1bedcfe1f877ccab8d

4 files changed, 3960 insertions, 249 deletions

diff --git a/lib/Transforms/Vectorize/BBVectorize.cpp b/lib/Transforms/Vectorize/BBVectorize.cpp
index c09dcd2..d72a4a1 100644
--- a/lib/Transforms/Vectorize/BBVectorize.cpp
+++ b/lib/Transforms/Vectorize/BBVectorize.cpp
@@ -16,42 +16,54 @@
 
 #define BBV_NAME "bb-vectorize"
 #define DEBUG_TYPE BBV_NAME
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/Function.h"
-#include "llvm/Instructions.h"
-#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/Transforms/Vectorize.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/STLExtras.h"
 #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/TargetTransformInfo.h"
 #include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/ValueHandle.h"
-#include "llvm/Target/TargetData.h"
+#include "llvm/Support/raw_ostream.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"));
@@ -93,8 +105,9 @@ 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), cl::Hidden,
+NoPointers("bb-vectorize-no-pointers", cl::init(/*false*/ true), cl::Hidden,
   cl::desc("Don't try to vectorize pointer values"));
 
 static cl::opt<bool>
@@ -159,6 +172,12 @@ 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");
@@ -177,13 +196,17 @@ namespace {
     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->getAnalysis<TargetTransformInfo>();
     }
 
     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,
@@ -191,8 +214,10 @@ namespace {
                 VPPIteratorPair;
 
     AliasAnalysis *AA;
+    DominatorTree *DT;
     ScalarEvolution *SE;
-    TargetData *TD;
+    DataLayout *TD;
+    const TargetTransformInfo *TTI;
 
     // FIXME: const correct?
 
@@ -201,11 +226,23 @@ namespace {
     bool getCandidatePairs(BasicBlock &BB,
                        BasicBlock::iterator &Start,
                        std::multimap<Value *, Value *> &CandidatePairs,
+                       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,
@@ -213,19 +250,29 @@ 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 NonPow2Len);
+                       bool IsSimpleLoadStore, bool NonPow2Len,
+                       int &CostSavings, int &FixedOrder);
 
     bool trackUsesOfI(DenseSet<Value *> &Users,
                       AliasSetTracker &WriteSet, Instruction *I,
@@ -236,6 +283,7 @@ 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,
@@ -267,17 +315,21 @@ 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 MaskOffset, unsigned NumInElem,
@@ -289,20 +341,20 @@ namespace {
 
     bool expandIEChain(LLVMContext& Context, Instruction *I, Instruction *J,
                        unsigned o, Value *&LOp, unsigned numElemL,
-                       Type *ArgTypeL, Type *ArgTypeR,
+                       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,
@@ -314,10 +366,6 @@ namespace {
                      DenseMap<Value *, Value *> &ChosenPairs,
                      std::multimap<Value *, Value *> &LoadMoveSet);
 
-    void collectPtrInfo(std::vector<Value *> &PairableInsts,
-                        DenseMap<Value *, Value *> &ChosenPairs,
-                        DenseSet<Value *> &LowPtrInsts);
-
     bool canMoveUsesOfIAfterJ(BasicBlock &BB,
                      std::multimap<Value *, Value *> &LoadMoveSet,
                      Instruction *I, Instruction *J);
@@ -330,13 +378,22 @@ namespace {
     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 (TTI) 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.
       unsigned n = 1;
       for (unsigned v = 2;
-           v <= Config.VectorBits && (!Config.MaxIter || n <= Config.MaxIter);
+           (TTI || v <= Config.VectorBits) &&
+           (!Config.MaxIter || n <= Config.MaxIter);
            v *= 2, ++n) {
         DEBUG(dbgs() << "BBV: fusing loop #" << n <<
               " for " << BB.getName() << " in " <<
@@ -363,8 +420,10 @@ namespace {
 
     virtual bool runOnBasicBlock(BasicBlock &BB) {
       AA = &getAnalysis<AliasAnalysis>();
+      DT = &getAnalysis<DominatorTree>();
       SE = &getAnalysis<ScalarEvolution>();
-      TD = getAnalysisIfAvailable<TargetData>();
+      TD = getAnalysisIfAvailable<DataLayout>();
+      TTI = IgnoreTargetInfo ? 0 : &getAnalysis<TargetTransformInfo>();
 
       return vectorizeBB(BB);
     }
@@ -372,8 +431,11 @@ namespace {
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       BasicBlockPass::getAnalysisUsage(AU);
       AU.addRequired<AliasAnalysis>();
+      AU.addRequired<DominatorTree>();
       AU.addRequired<ScalarEvolution>();
+      AU.addRequired<TargetTransformInfo>();
       AU.addPreserved<AliasAnalysis>();
+      AU.addPreserved<DominatorTree>();
       AU.addPreserved<ScalarEvolution>();
       AU.setPreservesCFG();
     }
@@ -415,6 +477,14 @@ namespace {
         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
@@ -446,6 +516,62 @@ namespace {
       return 1;
     }
 
+    // Returns the cost of the provided instruction using TTI.
+    // 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 TTI->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 TTI->getArithmeticInstrCost(Opcode, T1);
+      case Instruction::Select:
+      case Instruction::ICmp:
+      case Instruction::FCmp:
+        return TTI->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 TTI->getCastInstrCost(Opcode, T1, T2);
+      }
+
+      return 1;
+    }
+
     // This determines the relative offset of two loads or stores, returning
     // true if the offset could be determined to be some constant value.
     // For example, if OffsetInElmts == 1, then J accesses the memory directly
@@ -453,20 +579,30 @@ namespace {
     // 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);
 
@@ -502,7 +638,7 @@ namespace {
       Function *F = I->getCalledFunction();
       if (!F) return false;
 
-      unsigned IID = F->getIntrinsicID();
+      Intrinsic::ID IID = (Intrinsic::ID) F->getIntrinsicID();
       if (!IID) return false;
 
       switch(IID) {
@@ -520,6 +656,7 @@ namespace {
       case Intrinsic::pow:
         return Config.VectorizeMath;
       case Intrinsic::fma:
+      case Intrinsic::fmuladd:
         return Config.VectorizeFMA;
       }
     }
@@ -536,6 +673,19 @@ namespace {
 
       return false;
     }
+
+    bool isPureIEChain(InsertElementInst *IE) {
+      InsertElementInst *IENext = IE;
+      do {
+        if (!isa<UndefValue>(IENext->getOperand(0)) &&
+            !isa<InsertElementInst>(IENext->getOperand(0))) {
+          return false;
+        }
+      } while ((IENext =
+                 dyn_cast<InsertElementInst>(IENext->getOperand(0))));
+
+      return true;
+    }
   };
 
   // This function implements one vectorization iteration on the provided
@@ -546,11 +696,18 @@ namespace {
 
     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,
+                                         FixedOrderPairs,
+                                         CandidatePairCostSavings,
                                          PairableInsts, NonPow2Len);
       if (PairableInsts.empty()) continue;
 
@@ -563,10 +720,18 @@ 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);
@@ -578,13 +743,48 @@ 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;
@@ -597,7 +797,9 @@ 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.
@@ -667,15 +869,22 @@ namespace {
         !(VectorType::isValidElementType(T2) || T2->isVectorTy()))
       return false;
 
-    if (T1->getScalarSizeInBits() == 1 && T2->getScalarSizeInBits() == 1) {
+    if (T1->getScalarSizeInBits() == 1) {
       if (!Config.VectorizeBools)
         return false;
     } else {
-      if (!Config.VectorizeInts
-          && (T1->isIntOrIntVectorTy() || T2->isIntOrIntVectorTy()))
+      if (!Config.VectorizeInts && T1->isIntOrIntVectorTy())
         return false;
     }
-  
+
+    if (T2->getScalarSizeInBits() == 1) {
+      if (!Config.VectorizeBools)
+        return false;
+    } else {
+      if (!Config.VectorizeInts && T2->isIntOrIntVectorTy())
+        return false;
+    }
+
     if (!Config.VectorizeFloats
         && (T1->isFPOrFPVectorTy() || T2->isFPOrFPVectorTy()))
       return false;
@@ -691,8 +900,8 @@ namespace {
          T2->getScalarType()->isPointerTy()))
       return false;
 
-    if (T1->getPrimitiveSizeInBits() >= Config.VectorBits ||
-        T2->getPrimitiveSizeInBits() >= Config.VectorBits)
+    if (!TTI && (T1->getPrimitiveSizeInBits() >= Config.VectorBits ||
+                 T2->getPrimitiveSizeInBits() >= Config.VectorBits))
       return false;
 
     return true;
@@ -703,10 +912,14 @@ 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 NonPow2Len) {
+                       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.
     if (!J->isSameOperationAs(I, Instruction::CompareIgnoringAlignment |
@@ -719,52 +932,151 @@ namespace {
     unsigned MaxTypeBits = std::max(
       IT1->getPrimitiveSizeInBits() + JT1->getPrimitiveSizeInBits(),
       IT2->getPrimitiveSizeInBits() + JT2->getPrimitiveSizeInBits());
-    if (MaxTypeBits > Config.VectorBits)
+    if (!TTI && 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 (Config.AlignedOnly) {
-          Type *aTypeI = isa<StoreInst>(I) ?
-            cast<StoreInst>(I)->getValueOperand()->getType() : I->getType();
-          Type *aTypeJ = isa<StoreInst>(J) ?
-            cast<StoreInst>(J)->getValueOperand()->getType() : J->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(aTypeI, aTypeJ);
           unsigned VecAlignment = TD->getPrefTypeAlignment(VType);
           if (BottomAlignment < VecAlignment)
             return false;
         }
+
+        if (TTI) {
+          unsigned ICost = TTI->getMemoryOpCost(I->getOpcode(), aTypeI,
+                                                IAlignment, IAddressSpace);
+          unsigned JCost = TTI->getMemoryOpCost(J->getOpcode(), aTypeJ,
+                                                JAlignment, JAddressSpace);
+          unsigned VCost = TTI->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 = TTI->getNumberOfParts(VType);
+          if (VParts > 1)
+            return false;
+          else if (!VParts && VCost == ICost + JCost)
+            return false;
+
+          CostSavings = ICost + JCost - VCost;
+        }
       } else {
         return false;
       }
+    } else if (TTI) {
+      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 = TTI->getNumberOfParts(VT1),
+               VParts2 = TTI->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
     // vectorized, the second arguments must be equal.
     CallInst *CI = dyn_cast<CallInst>(I);
     Function *FI;
-    if (CI && (FI = CI->getCalledFunction()) &&
-        FI->getIntrinsicID() == Intrinsic::powi) {
-
-      Value *A1I = CI->getArgOperand(1),
-            *A1J = cast<CallInst>(J)->getArgOperand(1);
-      const SCEV *A1ISCEV = SE->getSCEV(A1I),
-                 *A1JSCEV = SE->getSCEV(A1J);
-      return (A1ISCEV == A1JSCEV);
+    if (CI && (FI = CI->getCalledFunction())) {
+      Intrinsic::ID IID = (Intrinsic::ID) FI->getIntrinsicID();
+      if (IID == Intrinsic::powi) {
+        Value *A1I = CI->getArgOperand(1),
+              *A1J = cast<CallInst>(J)->getArgOperand(1);
+        const SCEV *A1ISCEV = SE->getSCEV(A1I),
+                   *A1JSCEV = SE->getSCEV(A1J);
+        return (A1ISCEV == A1JSCEV);
+      }
+
+      if (IID && TTI) {
+        SmallVector<Type*, 4> Tys;
+        for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i)
+          Tys.push_back(CI->getArgOperand(i)->getType());
+        unsigned ICost = TTI->getIntrinsicInstrCost(IID, IT1, Tys);
+
+        Tys.clear();
+        CallInst *CJ = cast<CallInst>(J);
+        for (unsigned i = 0, ie = CJ->getNumArgOperands(); i != ie; ++i)
+          Tys.push_back(CJ->getArgOperand(i)->getType());
+        unsigned JCost = TTI->getIntrinsicInstrCost(IID, JT1, Tys);
+
+        Tys.clear();
+        assert(CI->getNumArgOperands() == CJ->getNumArgOperands() &&
+               "Intrinsic argument counts differ");
+        for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) {
+          if (IID == Intrinsic::powi && i == 1)
+            Tys.push_back(CI->getArgOperand(i)->getType());
+          else
+            Tys.push_back(getVecTypeForPair(CI->getArgOperand(i)->getType(),
+                                            CJ->getArgOperand(i)->getType()));
+        }
+
+        Type *RetTy = getVecTypeForPair(IT1, JT1);
+        unsigned VCost = TTI->getIntrinsicInstrCost(IID, RetTy, Tys);
+
+        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 RetParts = TTI->getNumberOfParts(RetTy);
+        if (RetParts > 1)
+          return false;
+        else if (!RetParts && VCost == ICost + JCost)
+          return false;
+
+        for (unsigned i = 0, ie = CI->getNumArgOperands(); i != ie; ++i) {
+          if (!Tys[i]->isVectorTy())
+            continue;
+
+          unsigned NumParts = TTI->getNumberOfParts(Tys[i]);
+          if (NumParts > 1)
+            return false;
+          else if (!NumParts && VCost == ICost + JCost)
+            return false;
+        }
+
+        CostSavings = ICost + JCost - VCost;
+      }
     }
 
     return true;
@@ -833,6 +1145,8 @@ namespace {
   bool BBVectorize::getCandidatePairs(BasicBlock &BB,
                        BasicBlock::iterator &Start,
                        std::multimap<Value *, Value *> &CandidatePairs,
+                       DenseSet<ValuePair> &FixedOrderPairs,
+                       DenseMap<ValuePair, int> &CandidatePairCostSavings,
                        std::vector<Value *> &PairableInsts, bool NonPow2Len) {
     BasicBlock::iterator E = BB.end();
     if (Start == E) return false;
@@ -869,7 +1183,9 @@ 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, NonPow2Len)) continue;
+        int CostSavings, FixedOrder;
+        if (!areInstsCompatible(I, J, IsSimpleLoadStore, NonPow2Len,
+            CostSavings, FixedOrder)) continue;
 
         // J is a candidate for merging with I.
         if (!PairableInsts.size() ||
@@ -878,6 +1194,14 @@ namespace {
         }
 
         CandidatePairs.insert(ValuePair(I, J));
+        if (TTI)
+          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.
@@ -887,7 +1211,8 @@ 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
@@ -915,6 +1240,7 @@ namespace {
                       std::multimap<Value *, Value *> &CandidatePairs,
                       std::vector<Value *> &PairableInsts,
                       std::multimap<ValuePair, ValuePair> &ConnectedPairs,
+                      DenseMap<VPPair, unsigned> &PairConnectionTypes,
                       ValuePair P) {
     StoreInst *SI, *SJ;
 
@@ -946,12 +1272,18 @@ namespace {
         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 (Config.SplatBreaksChain) continue;
@@ -962,8 +1294,11 @@ namespace {
             P.first == SJ->getPointerOperand())
           continue;
 
-        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, PairConnectionSplat));
+        }
       }
     }
 
@@ -985,8 +1320,11 @@ namespace {
             P.second == SJ->getPointerOperand())
           continue;
 
-        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, PairConnectionSplat));
+        }
       }
     }
   }
@@ -997,7 +1335,8 @@ 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) {
@@ -1006,7 +1345,7 @@ 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()
@@ -1196,7 +1535,7 @@ namespace {
       PrunedTree.insert(QTop.first);
 
       // Visit each child, pruning as necessary...
-      DenseMap<ValuePair, size_t> BestChildren;
+      SmallVector<ValuePairWithDepth, 8> BestChildren;
       VPPIteratorPair QTopRange = ConnectedPairs.equal_range(QTop.first);
       for (std::multimap<ValuePair, ValuePair>::iterator K = QTopRange.first;
            K != QTopRange.second; ++K) {
@@ -1228,7 +1567,7 @@ namespace {
         DenseSet<ValuePair> CurrentPairs;
 
         bool CanAdd = true;
-        for (DenseMap<ValuePair, size_t>::iterator C2
+        for (SmallVector<ValuePairWithDepth, 8>::iterator C2
               = BestChildren.begin(), E2 = BestChildren.end();
              C2 != E2; ++C2) {
           if (C2->first.first == C->first.first ||
@@ -1313,22 +1652,22 @@ namespace {
         // to an already-selected child. Check for this here, and if a
         // conflict is found, then remove the previously-selected child
         // before adding this one in its place.
-        for (DenseMap<ValuePair, size_t>::iterator C2
+        for (SmallVector<ValuePairWithDepth, 8>::iterator C2
               = BestChildren.begin(); C2 != BestChildren.end();) {
           if (C2->first.first == C->first.first ||
               C2->first.first == C->first.second ||
               C2->first.second == C->first.first ||
               C2->first.second == C->first.second ||
               pairsConflict(C2->first, C->first, PairableInstUsers))
-            BestChildren.erase(C2++);
+            C2 = BestChildren.erase(C2);
           else
             ++C2;
         }
 
-        BestChildren.insert(ValuePairWithDepth(C->first, C->second));
+        BestChildren.push_back(ValuePairWithDepth(C->first, C->second));
       }
 
-      for (DenseMap<ValuePair, size_t>::iterator C
+      for (SmallVector<ValuePairWithDepth, 8>::iterator C
             = BestChildren.begin(), E2 = BestChildren.end();
            C != E2; ++C) {
         size_t DepthF = getDepthFactor(C->first.first);
@@ -1341,13 +1680,17 @@ 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) {
@@ -1397,17 +1740,289 @@ 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 (TTI) {
+        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;
+
+        // If the cost model were perfect, this might not be necessary; but we
+        // need to make sure that we don't get stuck vectorizing our own
+        // shuffle chains.
+        bool HasNontrivialInsts = false;
+
+        // 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) {
+          if (!isa<ShuffleVectorInst>(S->first) &&
+              !isa<InsertElementInst>(S->first) &&
+              !isa<ExtractElementInst>(S->first))
+            HasNontrivialInsts = true;
+
+          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 (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) {
+                // Shuffle can be folded if it has no other input
+                if (isa<UndefValue>(SI->getOperand(1)))
+                  continue;
+              }
+              if (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) TTI->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 (ShuffleVectorInst *SI = dyn_cast<ShuffleVectorInst>(*I)) {
+                // Shuffle can be folded if it has no other input
+                if (isa<UndefValue>(SI->getOperand(1)))
+                  continue;
+              }
+              if (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) TTI->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) {
+                // If both are insert elements, then both can be widened.
+                InsertElementInst *IEO1 = dyn_cast<InsertElementInst>(O1),
+                                  *IEO2 = dyn_cast<InsertElementInst>(O2);
+                if (IEO1 && IEO2 && isPureIEChain(IEO1) && isPureIEChain(IEO2))
+                  continue;
+                // If both are extract elements, and both have the same input
+                // type, then they can be replaced with a shuffle
+                ExtractElementInst *EIO1 = dyn_cast<ExtractElementInst>(O1),
+                                   *EIO2 = dyn_cast<ExtractElementInst>(O2);
+                if (EIO1 && EIO2 &&
+                    EIO1->getOperand(0)->getType() ==
+                      EIO2->getOperand(0)->getType())
+                  continue;
+                // If both are a shuffle with equal operand types and only two
+                // unqiue operands, then they can be replaced with a single
+                // shuffle
+                ShuffleVectorInst *SIO1 = dyn_cast<ShuffleVectorInst>(O1),
+                                  *SIO2 = dyn_cast<ShuffleVectorInst>(O2);
+                if (SIO1 && SIO2 &&
+                    SIO1->getOperand(0)->getType() ==
+                      SIO2->getOperand(0)->getType()) {
+                  SmallSet<Value *, 4> SIOps;
+                  SIOps.insert(SIO1->getOperand(0));
+                  SIOps.insert(SIO1->getOperand(1));
+                  SIOps.insert(SIO2->getOperand(0));
+                  SIOps.insert(SIO2->getOperand(1));
+                  if (SIOps.size() <= 2)
+                    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) TTI->getVectorInstrCost(
+                                    Instruction::InsertElement, VTy, 0);
+                ESContrib += (int) TTI->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) TTI->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) TTI->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);
+            }
+          }
+        }
+
+        if (!HasNontrivialInsts) {
+          DEBUG(if (DebugPairSelection) dbgs() <<
+                "\tNo non-trivial instructions in tree;"
+                " override to zero effective size\n");
+          EffSize = 0;
+        }
+      } 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 >= Config.ReqChainDepth && EffSize > BestEffSize) {
+      if (((TTI && !UseChainDepthWithTI) ||
+            MaxDepth >= Config.ReqChainDepth) &&
+          EffSize > 0 && EffSize > BestEffSize) {
         BestMaxDepth = MaxDepth;
         BestEffSize = EffSize;
         BestTree = PrunedTree;
@@ -1419,8 +2034,12 @@ 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 =
@@ -1435,9 +2054,12 @@ 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);
@@ -1490,24 +2112,19 @@ 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 FlipMemInputs has
+    // 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 (!FlipMemInputs) {
-      VPtr = IPtr;
-    } else {
-      VPtr = JPtr;
-    }
+    Value *VPtr = IPtr;
 
     Type *ArgTypeI = cast<PointerType>(IPtr->getType())->getElementType();
     Type *ArgTypeJ = cast<PointerType>(JPtr->getType())->getElementType();
@@ -1515,7 +2132,7 @@ namespace {
     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,
@@ -1585,23 +2202,12 @@ namespace {
                                   Instruction *J, unsigned o, Value *&LOp,
                                   unsigned numElemL,
                                   Type *ArgTypeL, Type *ArgTypeH,
-                                  unsigned IdxOff) {
+                                  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) {
+      if (isPureIEChain(LIE)) {
         SmallVector<Value *, 8> VectElemts(numElemL,
           UndefValue::get(ArgTypeL->getScalarType()));
         InsertElementInst *LIENext = LIE;
@@ -1619,8 +2225,9 @@ namespace {
           LIENext = InsertElementInst::Create(LIEPrev, VectElemts[i],
                              ConstantInt::get(Type::getInt32Ty(Context),
                                               i + IdxOff),
-                             getReplacementName(I, true, o, i+1));
-          LIENext->insertBefore(J);
+                             getReplacementName(IBeforeJ ? I : J,
+                                                true, o, i+1));
+          LIENext->insertBefore(IBeforeJ ? J : I);
           LIEPrev = LIENext;
         }
 
@@ -1635,7 +2242,7 @@ namespace {
   // 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);
 
@@ -1646,12 +2253,6 @@ namespace {
 
     Instruction *L = I, *H = J;
     Type *ArgTypeL = ArgTypeI, *ArgTypeH = ArgTypeJ;
-    if (FlipMemInputs) {
-      L = J;
-      H = I;
-      ArgTypeL = ArgTypeJ;
-      ArgTypeH = ArgTypeI;
-    }
 
     unsigned numElemL;
     if (ArgTypeL->isVectorTy())
@@ -1804,8 +2405,9 @@ namespace {
           Instruction *S =
             new ShuffleVectorInst(I1, UndefValue::get(I1T),
                                   ConstantVector::get(Mask),
-                                  getReplacementName(I, true, o));
-          S->insertBefore(J);
+                                  getReplacementName(IBeforeJ ? I : J,
+                                                     true, o));
+          S->insertBefore(IBeforeJ ? J : I);
           return S;
         }
 
@@ -1826,8 +2428,9 @@ namespace {
           Instruction *NewI1 =
             new ShuffleVectorInst(I1, UndefValue::get(I1T),
                                   ConstantVector::get(Mask),
-                                  getReplacementName(I, true, o, 1));
-          NewI1->insertBefore(J);
+                                  getReplacementName(IBeforeJ ? I : J,
+                                                     true, o, 1));
+          NewI1->insertBefore(IBeforeJ ? J : I);
           I1 = NewI1;
           I1T = I2T;
           I1Elem = I2Elem;
@@ -1842,8 +2445,9 @@ namespace {
           Instruction *NewI2 =
             new ShuffleVectorInst(I2, UndefValue::get(I2T),
                                   ConstantVector::get(Mask),
-                                  getReplacementName(I, true, o, 1));
-          NewI2->insertBefore(J);
+                                  getReplacementName(IBeforeJ ? I : J,
+                                                     true, o, 1));
+          NewI2->insertBefore(IBeforeJ ? J : I);
           I2 = NewI2;
           I2T = I1T;
           I2Elem = I1Elem;
@@ -1863,8 +2467,8 @@ namespace {
 
         Instruction *NewOp =
           new ShuffleVectorInst(I1, I2, ConstantVector::get(Mask),
-                                getReplacementName(I, true, o));
-        NewOp->insertBefore(J);
+                                getReplacementName(IBeforeJ ? I : J, true, o));
+        NewOp->insertBefore(IBeforeJ ? J : I);
         return NewOp;
       }
     }
@@ -1872,17 +2476,17 @@ namespace {
     Type *ArgType = ArgTypeL;
     if (numElemL < numElemH) {
       if (numElemL == 1 && expandIEChain(Context, I, J, o, HOp, numElemH,
-                                         ArgTypeL, VArgType, 1)) {
+                                         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(I, true, o));
-        S->insertBefore(J);
+                           getReplacementName(IBeforeJ ? I : J, true, o));
+        S->insertBefore(IBeforeJ ? J : I);
         return S;
       } else if (!expandIEChain(Context, I, J, o, LOp, numElemL, ArgTypeL,
-                                ArgTypeH)) {
+                                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;
@@ -1897,29 +2501,32 @@ namespace {
     
           NLOp = new ShuffleVectorInst(LOp, UndefValue::get(ArgTypeL),
                                        ConstantVector::get(Mask),
-                                       getReplacementName(I, true, o, 1));
+                                       getReplacementName(IBeforeJ ? I : J,
+                                                          true, o, 1));
         } else {
           NLOp = InsertElementInst::Create(UndefValue::get(ArgTypeH), LOp, CV0,
-                                           getReplacementName(I, true, o, 1));
+                                           getReplacementName(IBeforeJ ? I : J,
+                                                              true, o, 1));
         }
   
-        NLOp->insertBefore(J);
+        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)) {
+                                         ArgTypeH, VArgType, IBeforeJ)) {
         Instruction *S =
           InsertElementInst::Create(LOp, HOp, 
                                     ConstantInt::get(Type::getInt32Ty(Context),
                                                      numElemL),
-                                    getReplacementName(I, true, o));
-        S->insertBefore(J);
+                                    getReplacementName(IBeforeJ ? I : J,
+                                                       true, o));
+        S->insertBefore(IBeforeJ ? J : I);
         return S;
       } else if (!expandIEChain(Context, I, J, o, HOp, numElemH, ArgTypeH,
-                                ArgTypeL)) {
+                                ArgTypeL, IBeforeJ)) {
         Instruction *NHOp;
         if (numElemH > 1) {
           std::vector<Constant *> Mask(numElemL);
@@ -1931,13 +2538,15 @@ namespace {
     
           NHOp = new ShuffleVectorInst(HOp, UndefValue::get(ArgTypeH),
                                        ConstantVector::get(Mask),
-                                       getReplacementName(I, true, o, 1));
+                                       getReplacementName(IBeforeJ ? I : J,
+                                                          true, o, 1));
         } else {
           NHOp = InsertElementInst::Create(UndefValue::get(ArgTypeL), HOp, CV0,
-                                           getReplacementName(I, true, o, 1));
+                                           getReplacementName(IBeforeJ ? I : J,
+                                                              true, o, 1));
         }
   
-        NHOp->insertBefore(J);
+        NHOp->insertBefore(IBeforeJ ? J : I);
         HOp = NHOp;
       }
     }
@@ -1955,19 +2564,21 @@ namespace {
       }
 
       Instruction *BV = new ShuffleVectorInst(LOp, HOp,
-                                              ConstantVector::get(Mask),
-                                              getReplacementName(I, true, o));
-      BV->insertBefore(J);
+                          ConstantVector::get(Mask),
+                          getReplacementName(IBeforeJ ? I : J, true, o));
+      BV->insertBefore(IBeforeJ ? J : I);
       return BV;
     }
 
     Instruction *BV1 = InsertElementInst::Create(
                                           UndefValue::get(VArgType), LOp, CV0,
-                                          getReplacementName(I, true, o, 1));
-    BV1->insertBefore(I);
+                                          getReplacementName(IBeforeJ ? I : J,
+                                                             true, o, 1));
+    BV1->insertBefore(IBeforeJ ? J : I);
     Instruction *BV2 = InsertElementInst::Create(BV1, HOp, CV1,
-                                          getReplacementName(I, true, o, 2));
-    BV2->insertBefore(J);
+                                          getReplacementName(IBeforeJ ? I : J,
+                                                             true, o, 2));
+    BV2->insertBefore(IBeforeJ ? J : I);
     return BV2;
   }
 
@@ -1976,7 +2587,7 @@ namespace {
   void BBVectorize::getReplacementInputsForPair(LLVMContext& Context,
                      Instruction *I, Instruction *J,
                      SmallVector<Value *, 3> &ReplacedOperands,
-                     bool FlipMemInputs) {
+                     bool IBeforeJ) {
     unsigned NumOperands = I->getNumOperands();
 
     for (unsigned p = 0, o = NumOperands-1; p < NumOperands; ++p, --o) {
@@ -1985,12 +2596,11 @@ 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();
+        Intrinsic::ID IID = (Intrinsic::ID) F->getIntrinsicID();
         if (o == NumOperands-1) {
           BasicBlock &BB = *I->getParent();
 
@@ -1999,8 +2609,7 @@ namespace {
           Type *ArgTypeJ = J->getType();
           Type *VArgType = getVecTypeForPair(ArgTypeI, ArgTypeJ);
 
-          ReplacedOperands[o] = Intrinsic::getDeclaration(M,
-            (Intrinsic::ID) IID, VArgType);
+          ReplacedOperands[o] = Intrinsic::getDeclaration(M, IID, VArgType);
           continue;
         } else if (IID == Intrinsic::powi && o == 1) {
           // The second argument of powi is a single integer and we've already
@@ -2014,8 +2623,7 @@ namespace {
         continue;
       }
 
-      ReplacedOperands[o] =
-        getReplacementInput(Context, I, J, o, FlipMemInputs);
+      ReplacedOperands[o] = getReplacementInput(Context, I, J, o, IBeforeJ);
     }
   }
 
@@ -2026,8 +2634,7 @@ namespace {
   void BBVectorize::replaceOutputsOfPair(LLVMContext& Context, Instruction *I,
                      Instruction *J, Instruction *K,
                      Instruction *&InsertionPt,
-                     Instruction *&K1, Instruction *&K2,
-                     bool FlipMemInputs) {
+                     Instruction *&K1, Instruction *&K2) {
     if (isa<StoreInst>(I)) {
       AA->replaceWithNewValue(I, K);
       AA->replaceWithNewValue(J, K);
@@ -2057,13 +2664,11 @@ namespace {
         }
 
         K1 = new ShuffleVectorInst(K, UndefValue::get(VType),
-                                   ConstantVector::get(
-                                     FlipMemInputs ? Mask2 : Mask1),
+                                   ConstantVector::get( Mask1),
                                    getReplacementName(K, false, 1));
       } else {
         Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
-        Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1);
-        K1 = ExtractElementInst::Create(K, FlipMemInputs ? CV1 : CV0,
+        K1 = ExtractElementInst::Create(K, CV0,
                                           getReplacementName(K, false, 1));
       }
 
@@ -2075,13 +2680,11 @@ namespace {
         }
 
         K2 = new ShuffleVectorInst(K, UndefValue::get(VType),
-                                   ConstantVector::get(
-                                     FlipMemInputs ? Mask1 : Mask2),
+                                   ConstantVector::get( Mask2),
                                    getReplacementName(K, false, 2));
       } else {
-        Value *CV0 = ConstantInt::get(Type::getInt32Ty(Context), 0);
         Value *CV1 = ConstantInt::get(Type::getInt32Ty(Context), numElem-1);
-        K2 = ExtractElementInst::Create(K, FlipMemInputs ? CV0 : CV1,
+        K2 = ExtractElementInst::Create(K, CV1,
                                           getReplacementName(K, false, 2));
       }
 
@@ -2181,36 +2784,6 @@ namespace {
     }
   }
 
-  // As with the aliasing information, SCEV can also change because of
-  // vectorization. This information is used to compute relative pointer
-  // offsets; the necessary information will be cached here prior to
-  // fusion.
-  void BBVectorize::collectPtrInfo(std::vector<Value *> &PairableInsts,
-                                   DenseMap<Value *, Value *> &ChosenPairs,
-                                   DenseSet<Value *> &LowPtrInsts) {
-    for (std::vector<Value *>::iterator PI = PairableInsts.begin(),
-      PIE = PairableInsts.end(); PI != PIE; ++PI) {
-      DenseMap<Value *, Value *>::iterator P = ChosenPairs.find(*PI);
-      if (P == ChosenPairs.end()) continue;
-
-      Instruction *I = cast<Instruction>(P->first);
-      Instruction *J = cast<Instruction>(P->second);
-
-      if (!isa<LoadInst>(I) && !isa<StoreInst>(I))
-        continue;
-
-      Value *IPtr, *JPtr;
-      unsigned IAlignment, JAlignment;
-      int64_t OffsetInElmts;
-      if (!getPairPtrInfo(I, J, IPtr, JPtr, IAlignment, JAlignment,
-                          OffsetInElmts) || abs64(OffsetInElmts) != 1)
-        llvm_unreachable("Pre-fusion pointer analysis failed");
-
-      Value *LowPI = (OffsetInElmts > 0) ? I : J;
-      LowPtrInsts.insert(LowPI);
-    }
-  }
-
   // 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.
@@ -2244,27 +2817,27 @@ 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);
 
     std::multimap<Value *, Value *> LoadMoveSet;
     collectLoadMoveSet(BB, PairableInsts, ChosenPairs, LoadMoveSet);
 
-    DenseSet<Value *> LowPtrInsts;
-    collectPtrInfo(PairableInsts, ChosenPairs, LowPtrInsts);
-
     DEBUG(dbgs() << "BBV: initial: \n" << BB << "\n");
 
     for (BasicBlock::iterator PI = BB.getFirstInsertionPt(); PI != BB.end();) {
@@ -2304,44 +2877,92 @@ namespace {
         continue;
       }
 
-      bool FlipMemInputs = false;
-      if (isa<LoadInst>(I) || isa<StoreInst>(I))
-        FlipMemInputs = (LowPtrInsts.find(I) == LowPtrInsts.end());
+      // 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(), J->getType()));
+        K->mutateType(getVecTypeForPair(L->getType(), H->getType()));
 
-      combineMetadata(K, J);
+      combineMetadata(K, H);
+      K->intersectOptionalDataWith(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
@@ -2351,10 +2972,10 @@ 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.
@@ -2387,6 +3008,9 @@ 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");
@@ -2397,6 +3021,8 @@ 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_AG_DEPENDENCY(TargetTransformInfo)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
 INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
 INITIALIZE_PASS_END(BBVectorize, BBV_NAME, bb_vectorize_name, false, false)
 
diff --git a/lib/Transforms/Vectorize/CMakeLists.txt b/lib/Transforms/Vectorize/CMakeLists.txt
index 06cf1e4..e64034a 100644
--- a/lib/Transforms/Vectorize/CMakeLists.txt
+++ b/lib/Transforms/Vectorize/CMakeLists.txt
@@ -1,6 +1,7 @@
 add_llvm_library(LLVMVectorize
   BBVectorize.cpp
   Vectorize.cpp
+  LoopVectorize.cpp
   )
 
 add_dependencies(LLVMVectorize intrinsics_gen)
diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
new file mode 100644
index 0000000..9c82cb8
--- /dev/null
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -0,0 +1,3080 @@
+//===- LoopVectorize.cpp - A Loop Vectorizer ------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is the LLVM loop vectorizer. This pass modifies 'vectorizable' loops
+// and generates target-independent LLVM-IR. Legalization of the IR is done
+// in the codegen. However, the vectorizes uses (will use) the codegen
+// interfaces to generate IR that is likely to result in an optimal binary.
+//
+// The loop vectorizer combines consecutive loop iteration into a single
+// 'wide' iteration. After this transformation the index is incremented
+// by the SIMD vector width, and not by one.
+//
+// This pass has three parts:
+// 1. The main loop pass that drives the different parts.
+// 2. LoopVectorizationLegality - A unit that checks for the legality
+//    of the vectorization.
+// 3. InnerLoopVectorizer - A unit that performs the actual
+//    widening of instructions.
+// 4. LoopVectorizationCostModel - A unit that checks for the profitability
+//    of vectorization. It decides on the optimal vector width, which
+//    can be one, if vectorization is not profitable.
+//
+//===----------------------------------------------------------------------===//
+//
+// The reduction-variable vectorization is based on the paper:
+//  D. Nuzman and R. Henderson. Multi-platform Auto-vectorization.
+//
+// Variable uniformity checks are inspired by:
+// Karrenberg, R. and Hack, S. Whole Function Vectorization.
+//
+// Other ideas/concepts are from:
+//  A. Zaks and D. Nuzman. Autovectorization in GCC-two years later.
+//
+//  S. Maleki, Y. Gao, M. Garzaran, T. Wong and D. Padua.  An Evaluation of
+//  Vectorizing Compilers.
+//
+//===----------------------------------------------------------------------===//
+
+#define LV_NAME "loop-vectorize"
+#define DEBUG_TYPE LV_NAME
+
+#include "llvm/Transforms/Vectorize.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/MapVector.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AliasSetTracker.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/LoopIterator.h"
+#include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/ScalarEvolutionExpander.h"
+#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Analysis/Verifier.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/IR/Value.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include <algorithm>
+#include <map>
+
+using namespace llvm;
+
+static cl::opt<unsigned>
+VectorizationFactor("force-vector-width", cl::init(0), cl::Hidden,
+                    cl::desc("Sets the SIMD width. Zero is autoselect."));
+
+static cl::opt<unsigned>
+VectorizationUnroll("force-vector-unroll", cl::init(0), cl::Hidden,
+                    cl::desc("Sets the vectorization unroll count. "
+                             "Zero is autoselect."));
+
+static cl::opt<bool>
+EnableIfConversion("enable-if-conversion", cl::init(true), cl::Hidden,
+                   cl::desc("Enable if-conversion during vectorization."));
+
+/// We don't vectorize loops with a known constant trip count below this number.
+static const unsigned TinyTripCountVectorThreshold = 16;
+
+/// We don't unroll loops with a known constant trip count below this number.
+static const unsigned TinyTripCountUnrollThreshold = 128;
+
+/// We don't unroll loops that are larget than this threshold.
+static const unsigned MaxLoopSizeThreshold = 32;
+
+/// When performing a runtime memory check, do not check more than this
+/// number of pointers. Notice that the check is quadratic!
+static const unsigned RuntimeMemoryCheckThreshold = 4;
+
+/// This is the highest vector width that we try to generate.
+static const unsigned MaxVectorSize = 8;
+
+/// This is the highest Unroll Factor.
+static const unsigned MaxUnrollSize = 4;
+
+namespace {
+
+// Forward declarations.
+class LoopVectorizationLegality;
+class LoopVectorizationCostModel;
+
+/// InnerLoopVectorizer vectorizes loops which contain only one basic
+/// block to a specified vectorization factor (VF).
+/// This class performs the widening of scalars into vectors, or multiple
+/// scalars. This class also implements the following features:
+/// * It inserts an epilogue loop for handling loops that don't have iteration
+///   counts that are known to be a multiple of the vectorization factor.
+/// * It handles the code generation for reduction variables.
+/// * Scalarization (implementation using scalars) of un-vectorizable
+///   instructions.
+/// InnerLoopVectorizer does not perform any vectorization-legality
+/// checks, and relies on the caller to check for the different legality
+/// aspects. The InnerLoopVectorizer relies on the
+/// LoopVectorizationLegality class to provide information about the induction
+/// and reduction variables that were found to a given vectorization factor.
+class InnerLoopVectorizer {
+public:
+  InnerLoopVectorizer(Loop *OrigLoop, ScalarEvolution *SE, LoopInfo *LI,
+                      DominatorTree *DT, DataLayout *DL, unsigned VecWidth,
+                      unsigned UnrollFactor)
+      : OrigLoop(OrigLoop), SE(SE), LI(LI), DT(DT), DL(DL), VF(VecWidth),
+        UF(UnrollFactor), Builder(SE->getContext()), Induction(0),
+        OldInduction(0), WidenMap(UnrollFactor) {}
+
+  // Perform the actual loop widening (vectorization).
+  void vectorize(LoopVectorizationLegality *Legal) {
+    // Create a new empty loop. Unlink the old loop and connect the new one.
+    createEmptyLoop(Legal);
+    // Widen each instruction in the old loop to a new one in the new loop.
+    // Use the Legality module to find the induction and reduction variables.
+    vectorizeLoop(Legal);
+    // Register the new loop and update the analysis passes.
+    updateAnalysis();
+  }
+
+private:
+  /// A small list of PHINodes.
+  typedef SmallVector<PHINode*, 4> PhiVector;
+  /// When we unroll loops we have multiple vector values for each scalar.
+  /// This data structure holds the unrolled and vectorized values that
+  /// originated from one scalar instruction.
+  typedef SmallVector<Value*, 2> VectorParts;
+
+  /// Add code that checks at runtime if the accessed arrays overlap.
+  /// Returns the comparator value or NULL if no check is needed.
+  Value *addRuntimeCheck(LoopVectorizationLegality *Legal,
+                         Instruction *Loc);
+  /// Create an empty loop, based on the loop ranges of the old loop.
+  void createEmptyLoop(LoopVectorizationLegality *Legal);
+  /// Copy and widen the instructions from the old loop.
+  void vectorizeLoop(LoopVectorizationLegality *Legal);
+
+  /// A helper function that computes the predicate of the block BB, assuming
+  /// that the header block of the loop is set to True. It returns the *entry*
+  /// mask for the block BB.
+  VectorParts createBlockInMask(BasicBlock *BB);
+  /// A helper function that computes the predicate of the edge between SRC
+  /// and DST.
+  VectorParts createEdgeMask(BasicBlock *Src, BasicBlock *Dst);
+
+  /// A helper function to vectorize a single BB within the innermost loop.
+  void vectorizeBlockInLoop(LoopVectorizationLegality *Legal, BasicBlock *BB,
+                            PhiVector *PV);
+
+  /// Insert the new loop to the loop hierarchy and pass manager
+  /// and update the analysis passes.
+  void updateAnalysis();
+
+  /// This instruction is un-vectorizable. Implement it as a sequence
+  /// of scalars.
+  void scalarizeInstruction(Instruction *Instr);
+
+  /// Create a broadcast instruction. This method generates a broadcast
+  /// instruction (shuffle) for loop invariant values and for the induction
+  /// value. If this is the induction variable then we extend it to N, N+1, ...
+  /// this is needed because each iteration in the loop corresponds to a SIMD
+  /// element.
+  Value *getBroadcastInstrs(Value *V);
+
+  /// This function adds 0, 1, 2 ... to each vector element, starting at zero.
+  /// If Negate is set then negative numbers are added e.g. (0, -1, -2, ...).
+  /// The sequence starts at StartIndex.
+  Value *getConsecutiveVector(Value* Val, unsigned StartIdx, bool Negate);
+
+  /// When we go over instructions in the basic block we rely on previous
+  /// values within the current basic block or on loop invariant values.
+  /// When we widen (vectorize) values we place them in the map. If the values
+  /// are not within the map, they have to be loop invariant, so we simply
+  /// broadcast them into a vector.
+  VectorParts &getVectorValue(Value *V);
+
+  /// Generate a shuffle sequence that will reverse the vector Vec.
+  Value *reverseVector(Value *Vec);
+
+  /// This is a helper class that holds the vectorizer state. It maps scalar
+  /// instructions to vector instructions. When the code is 'unrolled' then
+  /// then a single scalar value is mapped to multiple vector parts. The parts
+  /// are stored in the VectorPart type.
+  struct ValueMap {
+    /// C'tor.  UnrollFactor controls the number of vectors ('parts') that
+    /// are mapped.
+    ValueMap(unsigned UnrollFactor) : UF(UnrollFactor) {}
+
+    /// \return True if 'Key' is saved in the Value Map.
+    bool has(Value *Key) { return MapStoreage.count(Key); }
+
+    /// Initializes a new entry in the map. Sets all of the vector parts to the
+    /// save value in 'Val'.
+    /// \return A reference to a vector with splat values.
+    VectorParts &splat(Value *Key, Value *Val) {
+      MapStoreage[Key].clear();
+      MapStoreage[Key].append(UF, Val);
+      return MapStoreage[Key];
+    }
+
+    ///\return A reference to the value that is stored at 'Key'.
+    VectorParts &get(Value *Key) {
+      if (!has(Key))
+        MapStoreage[Key].resize(UF);
+      return MapStoreage[Key];
+    }
+
+    /// The unroll factor. Each entry in the map stores this number of vector
+    /// elements.
+    unsigned UF;
+
+    /// Map storage. We use std::map and not DenseMap because insertions to a
+    /// dense map invalidates its iterators.
+    std::map<Value*, VectorParts> MapStoreage;
+  };
+
+  /// The original loop.
+  Loop *OrigLoop;
+  /// Scev analysis to use.
+  ScalarEvolution *SE;
+  /// Loop Info.
+  LoopInfo *LI;
+  /// Dominator Tree.
+  DominatorTree *DT;
+  /// Data Layout.
+  DataLayout *DL;
+  /// The vectorization SIMD factor to use. Each vector will have this many
+  /// vector elements.
+  unsigned VF;
+  /// The vectorization unroll factor to use. Each scalar is vectorized to this
+  /// many different vector instructions.
+  unsigned UF;
+
+  /// The builder that we use
+  IRBuilder<> Builder;
+
+  // --- Vectorization state ---
+
+  /// The vector-loop preheader.
+  BasicBlock *LoopVectorPreHeader;
+  /// The scalar-loop preheader.
+  BasicBlock *LoopScalarPreHeader;
+  /// Middle Block between the vector and the scalar.
+  BasicBlock *LoopMiddleBlock;
+  ///The ExitBlock of the scalar loop.
+  BasicBlock *LoopExitBlock;
+  ///The vector loop body.
+  BasicBlock *LoopVectorBody;
+  ///The scalar loop body.
+  BasicBlock *LoopScalarBody;
+  ///The first bypass block.
+  BasicBlock *LoopBypassBlock;
+
+  /// The new Induction variable which was added to the new block.
+  PHINode *Induction;
+  /// The induction variable of the old basic block.
+  PHINode *OldInduction;
+  /// Maps scalars to widened vectors.
+  ValueMap WidenMap;
+};
+
+/// LoopVectorizationLegality checks if it is legal to vectorize a loop, and
+/// to what vectorization factor.
+/// This class does not look at the profitability of vectorization, only the
+/// legality. This class has two main kinds of checks:
+/// * Memory checks - The code in canVectorizeMemory checks if vectorization
+///   will change the order of memory accesses in a way that will change the
+///   correctness of the program.
+/// * Scalars checks - The code in canVectorizeInstrs and canVectorizeMemory
+/// checks for a number of different conditions, such as the availability of a
+/// single induction variable, that all types are supported and vectorize-able,
+/// etc. This code reflects the capabilities of InnerLoopVectorizer.
+/// This class is also used by InnerLoopVectorizer for identifying
+/// induction variable and the different reduction variables.
+class LoopVectorizationLegality {
+public:
+  LoopVectorizationLegality(Loop *L, ScalarEvolution *SE, DataLayout *DL,
+                            DominatorTree *DT)
+      : TheLoop(L), SE(SE), DL(DL), DT(DT), Induction(0) {}
+
+  /// This enum represents the kinds of reductions that we support.
+  enum ReductionKind {
+    RK_NoReduction, ///< Not a reduction.
+    RK_IntegerAdd,  ///< Sum of integers.
+    RK_IntegerMult, ///< Product of integers.
+    RK_IntegerOr,   ///< Bitwise or logical OR of numbers.
+    RK_IntegerAnd,  ///< Bitwise or logical AND of numbers.
+    RK_IntegerXor,  ///< Bitwise or logical XOR of numbers.
+    RK_FloatAdd,    ///< Sum of floats.
+    RK_FloatMult    ///< Product of floats.
+  };
+
+  /// This enum represents the kinds of inductions that we support.
+  enum InductionKind {
+    IK_NoInduction,         ///< Not an induction variable.
+    IK_IntInduction,        ///< Integer induction variable. Step = 1.
+    IK_ReverseIntInduction, ///< Reverse int induction variable. Step = -1.
+    IK_PtrInduction         ///< Pointer induction variable. Step = sizeof(elem).
+  };
+
+  /// This POD struct holds information about reduction variables.
+  struct ReductionDescriptor {
+    ReductionDescriptor() : StartValue(0), LoopExitInstr(0),
+      Kind(RK_NoReduction) {}
+
+    ReductionDescriptor(Value *Start, Instruction *Exit, ReductionKind K)
+        : StartValue(Start), LoopExitInstr(Exit), Kind(K) {}
+
+    // The starting value of the reduction.
+    // It does not have to be zero!
+    Value *StartValue;
+    // The instruction who's value is used outside the loop.
+    Instruction *LoopExitInstr;
+    // The kind of the reduction.
+    ReductionKind Kind;
+  };
+
+  // This POD struct holds information about the memory runtime legality
+  // check that a group of pointers do not overlap.
+  struct RuntimePointerCheck {
+    RuntimePointerCheck() : Need(false) {}
+
+    /// Reset the state of the pointer runtime information.
+    void reset() {
+      Need = false;
+      Pointers.clear();
+      Starts.clear();
+      Ends.clear();
+    }
+
+    /// Insert a pointer and calculate the start and end SCEVs.
+    void insert(ScalarEvolution *SE, Loop *Lp, Value *Ptr);
+
+    /// This flag indicates if we need to add the runtime check.
+    bool Need;
+    /// Holds the pointers that we need to check.
+    SmallVector<Value*, 2> Pointers;
+    /// Holds the pointer value at the beginning of the loop.
+    SmallVector<const SCEV*, 2> Starts;
+    /// Holds the pointer value at the end of the loop.
+    SmallVector<const SCEV*, 2> Ends;
+  };
+
+  /// A POD for saving information about induction variables.
+  struct InductionInfo {
+    InductionInfo(Value *Start, InductionKind K) : StartValue(Start), IK(K) {}
+    InductionInfo() : StartValue(0), IK(IK_NoInduction) {}
+    /// Start value.
+    Value *StartValue;
+    /// Induction kind.
+    InductionKind IK;
+  };
+
+  /// ReductionList contains the reduction descriptors for all
+  /// of the reductions that were found in the loop.
+  typedef DenseMap<PHINode*, ReductionDescriptor> ReductionList;
+
+  /// InductionList saves induction variables and maps them to the
+  /// induction descriptor.
+  typedef MapVector<PHINode*, InductionInfo> InductionList;
+
+  /// Returns true if it is legal to vectorize this loop.
+  /// This does not mean that it is profitable to vectorize this
+  /// loop, only that it is legal to do so.
+  bool canVectorize();
+
+  /// Returns the Induction variable.
+  PHINode *getInduction() { return Induction; }
+
+  /// Returns the reduction variables found in the loop.
+  ReductionList *getReductionVars() { return &Reductions; }
+
+  /// Returns the induction variables found in the loop.
+  InductionList *getInductionVars() { return &Inductions; }
+
+  /// Returns True if V is an induction variable in this loop.
+  bool isInductionVariable(const Value *V);
+
+  /// Return true if the block BB needs to be predicated in order for the loop
+  /// to be vectorized.
+  bool blockNeedsPredication(BasicBlock *BB);
+
+  /// Check if this  pointer is consecutive when vectorizing. This happens
+  /// when the last index of the GEP is the induction variable, or that the
+  /// pointer itself is an induction variable.
+  /// This check allows us to vectorize A[idx] into a wide load/store.
+  /// Returns:
+  /// 0 - Stride is unknown or non consecutive.
+  /// 1 - Address is consecutive.
+  /// -1 - Address is consecutive, and decreasing.
+  int isConsecutivePtr(Value *Ptr);
+
+  /// Returns true if the value V is uniform within the loop.
+  bool isUniform(Value *V);
+
+  /// Returns true if this instruction will remain scalar after vectorization.
+  bool isUniformAfterVectorization(Instruction* I) { return Uniforms.count(I); }
+
+  /// Returns the information that we collected about runtime memory check.
+  RuntimePointerCheck *getRuntimePointerCheck() { return &PtrRtCheck; }
+private:
+  /// Check if a single basic block loop is vectorizable.
+  /// At this point we know that this is a loop with a constant trip count
+  /// and we only need to check individual instructions.
+  bool canVectorizeInstrs();
+
+  /// When we vectorize loops we may change the order in which
+  /// we read and write from memory. This method checks if it is
+  /// legal to vectorize the code, considering only memory constrains.
+  /// Returns true if the loop is vectorizable
+  bool canVectorizeMemory();
+
+  /// Return true if we can vectorize this loop using the IF-conversion
+  /// transformation.
+  bool canVectorizeWithIfConvert();
+
+  /// Collect the variables that need to stay uniform after vectorization.
+  void collectLoopUniforms();
+
+  /// Return true if all of the instructions in the block can be speculatively
+  /// executed.
+  bool blockCanBePredicated(BasicBlock *BB);
+
+  /// Returns True, if 'Phi' is the kind of reduction variable for type
+  /// 'Kind'. If this is a reduction variable, it adds it to ReductionList.
+  bool AddReductionVar(PHINode *Phi, ReductionKind Kind);
+  /// Returns true if the instruction I can be a reduction variable of type
+  /// 'Kind'.
+  bool isReductionInstr(Instruction *I, ReductionKind Kind);
+  /// Returns the induction kind of Phi. This function may return NoInduction
+  /// if the PHI is not an induction variable.
+  InductionKind isInductionVariable(PHINode *Phi);
+  /// Return true if can compute the address bounds of Ptr within the loop.
+  bool hasComputableBounds(Value *Ptr);
+
+  /// The loop that we evaluate.
+  Loop *TheLoop;
+  /// Scev analysis.
+  ScalarEvolution *SE;
+  /// DataLayout analysis.
+  DataLayout *DL;
+  // Dominators.
+  DominatorTree *DT;
+
+  //  ---  vectorization state --- //
+
+  /// Holds the integer induction variable. This is the counter of the
+  /// loop.
+  PHINode *Induction;
+  /// Holds the reduction variables.
+  ReductionList Reductions;
+  /// Holds all of the induction variables that we found in the loop.
+  /// Notice that inductions don't need to start at zero and that induction
+  /// variables can be pointers.
+  InductionList Inductions;
+
+  /// Allowed outside users. This holds the reduction
+  /// vars which can be accessed from outside the loop.
+  SmallPtrSet<Value*, 4> AllowedExit;
+  /// This set holds the variables which are known to be uniform after
+  /// vectorization.
+  SmallPtrSet<Instruction*, 4> Uniforms;
+  /// We need to check that all of the pointers in this list are disjoint
+  /// at runtime.
+  RuntimePointerCheck PtrRtCheck;
+};
+
+/// LoopVectorizationCostModel - estimates the expected speedups due to
+/// vectorization.
+/// In many cases vectorization is not profitable. This can happen because of
+/// a number of reasons. In this class we mainly attempt to predict the
+/// expected speedup/slowdowns due to the supported instruction set. We use the
+/// TargetTransformInfo to query the different backends for the cost of
+/// different operations.
+class LoopVectorizationCostModel {
+public:
+  LoopVectorizationCostModel(Loop *L, ScalarEvolution *SE, LoopInfo *LI,
+                             LoopVectorizationLegality *Legal,
+                             const TargetTransformInfo &TTI)
+      : TheLoop(L), SE(SE), LI(LI), Legal(Legal), TTI(TTI) {}
+
+  /// \return The most profitable vectorization factor.
+  /// This method checks every power of two up to VF. If UserVF is not ZERO
+  /// then this vectorization factor will be selected if vectorization is
+  /// possible.
+  unsigned selectVectorizationFactor(bool OptForSize, unsigned UserVF);
+
+
+  /// \return The most profitable unroll factor.
+  /// If UserUF is non-zero then this method finds the best unroll-factor
+  /// based on register pressure and other parameters.
+  unsigned selectUnrollFactor(bool OptForSize, unsigned UserUF);
+
+  /// \brief A struct that represents some properties of the register usage
+  /// of a loop.
+  struct RegisterUsage {
+    /// Holds the number of loop invariant values that are used in the loop.
+    unsigned LoopInvariantRegs;
+    /// Holds the maximum number of concurrent live intervals in the loop.
+    unsigned MaxLocalUsers;
+    /// Holds the number of instructions in the loop.
+    unsigned NumInstructions;
+  };
+
+  /// \return  information about the register usage of the loop.
+  RegisterUsage calculateRegisterUsage();
+
+private:
+  /// Returns the expected execution cost. The unit of the cost does
+  /// not matter because we use the 'cost' units to compare different
+  /// vector widths. The cost that is returned is *not* normalized by
+  /// the factor width.
+  unsigned expectedCost(unsigned VF);
+
+  /// Returns the execution time cost of an instruction for a given vector
+  /// width. Vector width of one means scalar.
+  unsigned getInstructionCost(Instruction *I, unsigned VF);
+
+  /// A helper function for converting Scalar types to vector types.
+  /// If the incoming type is void, we return void. If the VF is 1, we return
+  /// the scalar type.
+  static Type* ToVectorTy(Type *Scalar, unsigned VF);
+
+  /// The loop that we evaluate.
+  Loop *TheLoop;
+  /// Scev analysis.
+  ScalarEvolution *SE;
+  /// Loop Info analysis.
+  LoopInfo *LI;
+  /// Vectorization legality.
+  LoopVectorizationLegality *Legal;
+  /// Vector target information.
+  const TargetTransformInfo &TTI;
+};
+
+/// The LoopVectorize Pass.
+struct LoopVectorize : public LoopPass {
+  /// Pass identification, replacement for typeid
+  static char ID;
+
+  explicit LoopVectorize() : LoopPass(ID) {
+    initializeLoopVectorizePass(*PassRegistry::getPassRegistry());
+  }
+
+  ScalarEvolution *SE;
+  DataLayout *DL;
+  LoopInfo *LI;
+  TargetTransformInfo *TTI;
+  DominatorTree *DT;
+
+  virtual bool runOnLoop(Loop *L, LPPassManager &LPM) {
+    // We only vectorize innermost loops.
+    if (!L->empty())
+      return false;
+
+    SE = &getAnalysis<ScalarEvolution>();
+    DL = getAnalysisIfAvailable<DataLayout>();
+    LI = &getAnalysis<LoopInfo>();
+    TTI = &getAnalysis<TargetTransformInfo>();
+    DT = &getAnalysis<DominatorTree>();
+
+    DEBUG(dbgs() << "LV: Checking a loop in \"" <<
+          L->getHeader()->getParent()->getName() << "\"\n");
+
+    // Check if it is legal to vectorize the loop.
+    LoopVectorizationLegality LVL(L, SE, DL, DT);
+    if (!LVL.canVectorize()) {
+      DEBUG(dbgs() << "LV: Not vectorizing.\n");
+      return false;
+    }
+
+    // Use the cost model.
+    LoopVectorizationCostModel CM(L, SE, LI, &LVL, *TTI);
+
+    // Check the function attribues to find out if this function should be
+    // optimized for size.
+    Function *F = L->getHeader()->getParent();
+    Attribute::AttrKind SzAttr = Attribute::OptimizeForSize;
+    Attribute::AttrKind FlAttr = Attribute::NoImplicitFloat;
+    unsigned FnIndex = AttributeSet::FunctionIndex;
+    bool OptForSize = F->getAttributes().hasAttribute(FnIndex, SzAttr);
+    bool NoFloat = F->getAttributes().hasAttribute(FnIndex, FlAttr);
+
+    if (NoFloat) {
+      DEBUG(dbgs() << "LV: Can't vectorize when the NoImplicitFloat"
+            "attribute is used.\n");
+      return false;
+    }
+
+    unsigned VF = CM.selectVectorizationFactor(OptForSize, VectorizationFactor);
+    unsigned UF = CM.selectUnrollFactor(OptForSize, VectorizationUnroll);
+
+    if (VF == 1) {
+      DEBUG(dbgs() << "LV: Vectorization is possible but not beneficial.\n");
+      return false;
+    }
+
+    DEBUG(dbgs() << "LV: Found a vectorizable loop ("<< VF << ") in "<<
+          F->getParent()->getModuleIdentifier()<<"\n");
+    DEBUG(dbgs() << "LV: Unroll Factor is " << UF << "\n");
+
+    // If we decided that it is *legal* to vectorizer the loop then do it.
+    InnerLoopVectorizer LB(L, SE, LI, DT, DL, VF, UF);
+    LB.vectorize(&LVL);
+
+    DEBUG(verifyFunction(*L->getHeader()->getParent()));
+    return true;
+  }
+
+  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+    LoopPass::getAnalysisUsage(AU);
+    AU.addRequiredID(LoopSimplifyID);
+    AU.addRequiredID(LCSSAID);
+    AU.addRequired<DominatorTree>();
+    AU.addRequired<LoopInfo>();
+    AU.addRequired<ScalarEvolution>();
+    AU.addRequired<TargetTransformInfo>();
+    AU.addPreserved<LoopInfo>();
+    AU.addPreserved<DominatorTree>();
+  }
+
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// Implementation of LoopVectorizationLegality, InnerLoopVectorizer and
+// LoopVectorizationCostModel.
+//===----------------------------------------------------------------------===//
+
+void
+LoopVectorizationLegality::RuntimePointerCheck::insert(ScalarEvolution *SE,
+                                                       Loop *Lp, Value *Ptr) {
+  const SCEV *Sc = SE->getSCEV(Ptr);
+  const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Sc);
+  assert(AR && "Invalid addrec expression");
+  const SCEV *Ex = SE->getExitCount(Lp, Lp->getLoopLatch());
+  const SCEV *ScEnd = AR->evaluateAtIteration(Ex, *SE);
+  Pointers.push_back(Ptr);
+  Starts.push_back(AR->getStart());
+  Ends.push_back(ScEnd);
+}
+
+Value *InnerLoopVectorizer::getBroadcastInstrs(Value *V) {
+  // Save the current insertion location.
+  Instruction *Loc = Builder.GetInsertPoint();
+
+  // We need to place the broadcast of invariant variables outside the loop.
+  Instruction *Instr = dyn_cast<Instruction>(V);
+  bool NewInstr = (Instr && Instr->getParent() == LoopVectorBody);
+  bool Invariant = OrigLoop->isLoopInvariant(V) && !NewInstr;
+
+  // Place the code for broadcasting invariant variables in the new preheader.
+  if (Invariant)
+    Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
+
+  // Broadcast the scalar into all locations in the vector.
+  Value *Shuf = Builder.CreateVectorSplat(VF, V, "broadcast");
+
+  // Restore the builder insertion point.
+  if (Invariant)
+    Builder.SetInsertPoint(Loc);
+
+  return Shuf;
+}
+
+Value *InnerLoopVectorizer::getConsecutiveVector(Value* Val, unsigned StartIdx,
+                                                 bool Negate) {
+  assert(Val->getType()->isVectorTy() && "Must be a vector");
+  assert(Val->getType()->getScalarType()->isIntegerTy() &&
+         "Elem must be an integer");
+  // Create the types.
+  Type *ITy = Val->getType()->getScalarType();
+  VectorType *Ty = cast<VectorType>(Val->getType());
+  int VLen = Ty->getNumElements();
+  SmallVector<Constant*, 8> Indices;
+
+  // Create a vector of consecutive numbers from zero to VF.
+  for (int i = 0; i < VLen; ++i) {
+    int Idx = Negate ? (-i): i;
+    Indices.push_back(ConstantInt::get(ITy, StartIdx + Idx));
+  }
+
+  // Add the consecutive indices to the vector value.
+  Constant *Cv = ConstantVector::get(Indices);
+  assert(Cv->getType() == Val->getType() && "Invalid consecutive vec");
+  return Builder.CreateAdd(Val, Cv, "induction");
+}
+
+int LoopVectorizationLegality::isConsecutivePtr(Value *Ptr) {
+  assert(Ptr->getType()->isPointerTy() && "Unexpected non ptr");
+
+  // If this value is a pointer induction variable we know it is consecutive.
+  PHINode *Phi = dyn_cast_or_null<PHINode>(Ptr);
+  if (Phi && Inductions.count(Phi)) {
+    InductionInfo II = Inductions[Phi];
+    if (IK_PtrInduction == II.IK)
+      return 1;
+  }
+
+  GetElementPtrInst *Gep = dyn_cast_or_null<GetElementPtrInst>(Ptr);
+  if (!Gep)
+    return 0;
+
+  unsigned NumOperands = Gep->getNumOperands();
+  Value *LastIndex = Gep->getOperand(NumOperands - 1);
+
+  // Check that all of the gep indices are uniform except for the last.
+  for (unsigned i = 0; i < NumOperands - 1; ++i)
+    if (!SE->isLoopInvariant(SE->getSCEV(Gep->getOperand(i)), TheLoop))
+      return 0;
+
+  // We can emit wide load/stores only if the last index is the induction
+  // variable.
+  const SCEV *Last = SE->getSCEV(LastIndex);
+  if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Last)) {
+    const SCEV *Step = AR->getStepRecurrence(*SE);
+
+    // The memory is consecutive because the last index is consecutive
+    // and all other indices are loop invariant.
+    if (Step->isOne())
+      return 1;
+    if (Step->isAllOnesValue())
+      return -1;
+  }
+
+  return 0;
+}
+
+bool LoopVectorizationLegality::isUniform(Value *V) {
+  return (SE->isLoopInvariant(SE->getSCEV(V), TheLoop));
+}
+
+InnerLoopVectorizer::VectorParts&
+InnerLoopVectorizer::getVectorValue(Value *V) {
+  assert(V != Induction && "The new induction variable should not be used.");
+  assert(!V->getType()->isVectorTy() && "Can't widen a vector");
+
+  // If we have this scalar in the map, return it.
+  if (WidenMap.has(V))
+    return WidenMap.get(V);
+
+  // If this scalar is unknown, assume that it is a constant or that it is
+  // loop invariant. Broadcast V and save the value for future uses.
+  Value *B = getBroadcastInstrs(V);
+  WidenMap.splat(V, B);
+  return WidenMap.get(V);
+}
+
+Value *InnerLoopVectorizer::reverseVector(Value *Vec) {
+  assert(Vec->getType()->isVectorTy() && "Invalid type");
+  SmallVector<Constant*, 8> ShuffleMask;
+  for (unsigned i = 0; i < VF; ++i)
+    ShuffleMask.push_back(Builder.getInt32(VF - i - 1));
+
+  return Builder.CreateShuffleVector(Vec, UndefValue::get(Vec->getType()),
+                                     ConstantVector::get(ShuffleMask),
+                                     "reverse");
+}
+
+void InnerLoopVectorizer::scalarizeInstruction(Instruction *Instr) {
+  assert(!Instr->getType()->isAggregateType() && "Can't handle vectors");
+  // Holds vector parameters or scalars, in case of uniform vals.
+  SmallVector<VectorParts, 4> Params;
+
+  // Find all of the vectorized parameters.
+  for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) {
+    Value *SrcOp = Instr->getOperand(op);
+
+    // If we are accessing the old induction variable, use the new one.
+    if (SrcOp == OldInduction) {
+      Params.push_back(getVectorValue(SrcOp));
+      continue;
+    }
+
+    // Try using previously calculated values.
+    Instruction *SrcInst = dyn_cast<Instruction>(SrcOp);
+
+    // If the src is an instruction that appeared earlier in the basic block
+    // then it should already be vectorized.
+    if (SrcInst && OrigLoop->contains(SrcInst)) {
+      assert(WidenMap.has(SrcInst) && "Source operand is unavailable");
+      // The parameter is a vector value from earlier.
+      Params.push_back(WidenMap.get(SrcInst));
+    } else {
+      // The parameter is a scalar from outside the loop. Maybe even a constant.
+      VectorParts Scalars;
+      Scalars.append(UF, SrcOp);
+      Params.push_back(Scalars);
+    }
+  }
+
+  assert(Params.size() == Instr->getNumOperands() &&
+         "Invalid number of operands");
+
+  // Does this instruction return a value ?
+  bool IsVoidRetTy = Instr->getType()->isVoidTy();
+
+  Value *UndefVec = IsVoidRetTy ? 0 :
+    UndefValue::get(VectorType::get(Instr->getType(), VF));
+  // Create a new entry in the WidenMap and initialize it to Undef or Null.
+  VectorParts &VecResults = WidenMap.splat(Instr, UndefVec);
+
+  // For each scalar that we create:
+  for (unsigned Width = 0; Width < VF; ++Width) {
+    // For each vector unroll 'part':
+    for (unsigned Part = 0; Part < UF; ++Part) {
+      Instruction *Cloned = Instr->clone();
+      if (!IsVoidRetTy)
+        Cloned->setName(Instr->getName() + ".cloned");
+      // Replace the operands of the cloned instrucions with extracted scalars.
+      for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) {
+        Value *Op = Params[op][Part];
+        // Param is a vector. Need to extract the right lane.
+        if (Op->getType()->isVectorTy())
+          Op = Builder.CreateExtractElement(Op, Builder.getInt32(Width));
+        Cloned->setOperand(op, Op);
+      }
+
+      // Place the cloned scalar in the new loop.
+      Builder.Insert(Cloned);
+
+      // If the original scalar returns a value we need to place it in a vector
+      // so that future users will be able to use it.
+      if (!IsVoidRetTy)
+        VecResults[Part] = Builder.CreateInsertElement(VecResults[Part], Cloned,
+                                                       Builder.getInt32(Width));
+    }
+  }
+}
+
+Value*
+InnerLoopVectorizer::addRuntimeCheck(LoopVectorizationLegality *Legal,
+                                     Instruction *Loc) {
+  LoopVectorizationLegality::RuntimePointerCheck *PtrRtCheck =
+  Legal->getRuntimePointerCheck();
+
+  if (!PtrRtCheck->Need)
+    return NULL;
+
+  Value *MemoryRuntimeCheck = 0;
+  unsigned NumPointers = PtrRtCheck->Pointers.size();
+  SmallVector<Value* , 2> Starts;
+  SmallVector<Value* , 2> Ends;
+
+  SCEVExpander Exp(*SE, "induction");
+
+  // Use this type for pointer arithmetic.
+  Type* PtrArithTy = Type::getInt8PtrTy(Loc->getContext(), 0);
+
+  for (unsigned i = 0; i < NumPointers; ++i) {
+    Value *Ptr = PtrRtCheck->Pointers[i];
+    const SCEV *Sc = SE->getSCEV(Ptr);
+
+    if (SE->isLoopInvariant(Sc, OrigLoop)) {
+      DEBUG(dbgs() << "LV: Adding RT check for a loop invariant ptr:" <<
+            *Ptr <<"\n");
+      Starts.push_back(Ptr);
+      Ends.push_back(Ptr);
+    } else {
+      DEBUG(dbgs() << "LV: Adding RT check for range:" << *Ptr <<"\n");
+
+      Value *Start = Exp.expandCodeFor(PtrRtCheck->Starts[i], PtrArithTy, Loc);
+      Value *End = Exp.expandCodeFor(PtrRtCheck->Ends[i], PtrArithTy, Loc);
+      Starts.push_back(Start);
+      Ends.push_back(End);
+    }
+  }
+
+  for (unsigned i = 0; i < NumPointers; ++i) {
+    for (unsigned j = i+1; j < NumPointers; ++j) {
+      Instruction::CastOps Op = Instruction::BitCast;
+      Value *Start0 = CastInst::Create(Op, Starts[i], PtrArithTy, "bc", Loc);
+      Value *Start1 = CastInst::Create(Op, Starts[j], PtrArithTy, "bc", Loc);
+      Value *End0 =   CastInst::Create(Op, Ends[i],   PtrArithTy, "bc", Loc);
+      Value *End1 =   CastInst::Create(Op, Ends[j],   PtrArithTy, "bc", Loc);
+
+      Value *Cmp0 = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_ULE,
+                                    Start0, End1, "bound0", Loc);
+      Value *Cmp1 = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_ULE,
+                                    Start1, End0, "bound1", Loc);
+      Value *IsConflict = BinaryOperator::Create(Instruction::And, Cmp0, Cmp1,
+                                                 "found.conflict", Loc);
+      if (MemoryRuntimeCheck)
+        MemoryRuntimeCheck = BinaryOperator::Create(Instruction::Or,
+                                                    MemoryRuntimeCheck,
+                                                    IsConflict,
+                                                    "conflict.rdx", Loc);
+      else
+        MemoryRuntimeCheck = IsConflict;
+
+    }
+  }
+
+  return MemoryRuntimeCheck;
+}
+
+void
+InnerLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) {
+  /*
+   In this function we generate a new loop. The new loop will contain
+   the vectorized instructions while the old loop will continue to run the
+   scalar remainder.
+
+       [ ] <-- vector loop bypass.
+     /  |
+    /   v
+   |   [ ]     <-- vector pre header.
+   |    |
+   |    v
+   |   [  ] \
+   |   [  ]_|   <-- vector loop.
+   |    |
+    \   v
+      >[ ]   <--- middle-block.
+     /  |
+    /   v
+   |   [ ]     <--- new preheader.
+   |    |
+   |    v
+   |   [ ] \
+   |   [ ]_|   <-- old scalar loop to handle remainder.
+    \   |
+     \  v
+      >[ ]     <-- exit block.
+   ...
+   */
+
+  BasicBlock *OldBasicBlock = OrigLoop->getHeader();
+  BasicBlock *BypassBlock = OrigLoop->getLoopPreheader();
+  BasicBlock *ExitBlock = OrigLoop->getExitBlock();
+  assert(ExitBlock && "Must have an exit block");
+
+  // Some loops have a single integer induction variable, while other loops
+  // don't. One example is c++ iterators that often have multiple pointer
+  // induction variables. In the code below we also support a case where we
+  // don't have a single induction variable.
+  OldInduction = Legal->getInduction();
+  Type *IdxTy = OldInduction ? OldInduction->getType() :
+  DL->getIntPtrType(SE->getContext());
+
+  // Find the loop boundaries.
+  const SCEV *ExitCount = SE->getExitCount(OrigLoop, OrigLoop->getLoopLatch());
+  assert(ExitCount != SE->getCouldNotCompute() && "Invalid loop count");
+
+  // Get the total trip count from the count by adding 1.
+  ExitCount = SE->getAddExpr(ExitCount,
+                             SE->getConstant(ExitCount->getType(), 1));
+
+  // Expand the trip count and place the new instructions in the preheader.
+  // Notice that the pre-header does not change, only the loop body.
+  SCEVExpander Exp(*SE, "induction");
+
+  // Count holds the overall loop count (N).
+  Value *Count = Exp.expandCodeFor(ExitCount, ExitCount->getType(),
+                                   BypassBlock->getTerminator());
+
+  // The loop index does not have to start at Zero. Find the original start
+  // value from the induction PHI node. If we don't have an induction variable
+  // then we know that it starts at zero.
+  Value *StartIdx = OldInduction ?
+  OldInduction->getIncomingValueForBlock(BypassBlock):
+  ConstantInt::get(IdxTy, 0);
+
+  assert(BypassBlock && "Invalid loop structure");
+
+  // Generate the code that checks in runtime if arrays overlap.
+  Value *MemoryRuntimeCheck = addRuntimeCheck(Legal,
+                                              BypassBlock->getTerminator());
+
+  // Split the single block loop into the two loop structure described above.
+  BasicBlock *VectorPH =
+  BypassBlock->splitBasicBlock(BypassBlock->getTerminator(), "vector.ph");
+  BasicBlock *VecBody =
+  VectorPH->splitBasicBlock(VectorPH->getTerminator(), "vector.body");
+  BasicBlock *MiddleBlock =
+  VecBody->splitBasicBlock(VecBody->getTerminator(), "middle.block");
+  BasicBlock *ScalarPH =
+  MiddleBlock->splitBasicBlock(MiddleBlock->getTerminator(), "scalar.ph");
+
+  // This is the location in which we add all of the logic for bypassing
+  // the new vector loop.
+  Instruction *Loc = BypassBlock->getTerminator();
+
+  // Use this IR builder to create the loop instructions (Phi, Br, Cmp)
+  // inside the loop.
+  Builder.SetInsertPoint(VecBody->getFirstInsertionPt());
+
+  // Generate the induction variable.
+  Induction = Builder.CreatePHI(IdxTy, 2, "index");
+  // The loop step is equal to the vectorization factor (num of SIMD elements)
+  // times the unroll factor (num of SIMD instructions).
+  Constant *Step = ConstantInt::get(IdxTy, VF * UF);
+
+  // We may need to extend the index in case there is a type mismatch.
+  // We know that the count starts at zero and does not overflow.
+  if (Count->getType() != IdxTy) {
+    // The exit count can be of pointer type. Convert it to the correct
+    // integer type.
+    if (ExitCount->getType()->isPointerTy())
+      Count = CastInst::CreatePointerCast(Count, IdxTy, "ptrcnt.to.int", Loc);
+    else
+      Count = CastInst::CreateZExtOrBitCast(Count, IdxTy, "zext.cnt", Loc);
+  }
+
+  // Add the start index to the loop count to get the new end index.
+  Value *IdxEnd = BinaryOperator::CreateAdd(Count, StartIdx, "end.idx", Loc);
+
+  // Now we need to generate the expression for N - (N % VF), which is
+  // the part that the vectorized body will execute.
+  Value *R = BinaryOperator::CreateURem(Count, Step, "n.mod.vf", Loc);
+  Value *CountRoundDown = BinaryOperator::CreateSub(Count, R, "n.vec", Loc);
+  Value *IdxEndRoundDown = BinaryOperator::CreateAdd(CountRoundDown, StartIdx,
+                                                     "end.idx.rnd.down", Loc);
+
+  // Now, compare the new count to zero. If it is zero skip the vector loop and
+  // jump to the scalar loop.
+  Value *Cmp = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ,
+                               IdxEndRoundDown,
+                               StartIdx,
+                               "cmp.zero", Loc);
+
+  // If we are using memory runtime checks, include them in.
+  if (MemoryRuntimeCheck)
+    Cmp = BinaryOperator::Create(Instruction::Or, Cmp, MemoryRuntimeCheck,
+                                 "CntOrMem", Loc);
+
+  BranchInst::Create(MiddleBlock, VectorPH, Cmp, Loc);
+  // Remove the old terminator.
+  Loc->eraseFromParent();
+
+  // We are going to resume the execution of the scalar loop.
+  // Go over all of the induction variables that we found and fix the
+  // PHIs that are left in the scalar version of the loop.
+  // The starting values of PHI nodes depend on the counter of the last
+  // iteration in the vectorized loop.
+  // If we come from a bypass edge then we need to start from the original
+  // start value.
+
+  // This variable saves the new starting index for the scalar loop.
+  PHINode *ResumeIndex = 0;
+  LoopVectorizationLegality::InductionList::iterator I, E;
+  LoopVectorizationLegality::InductionList *List = Legal->getInductionVars();
+  for (I = List->begin(), E = List->end(); I != E; ++I) {
+    PHINode *OrigPhi = I->first;
+    LoopVectorizationLegality::InductionInfo II = I->second;
+    PHINode *ResumeVal = PHINode::Create(OrigPhi->getType(), 2, "resume.val",
+                                         MiddleBlock->getTerminator());
+    Value *EndValue = 0;
+    switch (II.IK) {
+    case LoopVectorizationLegality::IK_NoInduction:
+      llvm_unreachable("Unknown induction");
+    case LoopVectorizationLegality::IK_IntInduction: {
+      // Handle the integer induction counter:
+      assert(OrigPhi->getType()->isIntegerTy() && "Invalid type");
+      assert(OrigPhi == OldInduction && "Unknown integer PHI");
+      // We know what the end value is.
+      EndValue = IdxEndRoundDown;
+      // We also know which PHI node holds it.
+      ResumeIndex = ResumeVal;
+      break;
+    }
+    case LoopVectorizationLegality::IK_ReverseIntInduction: {
+      // Convert the CountRoundDown variable to the PHI size.
+      unsigned CRDSize = CountRoundDown->getType()->getScalarSizeInBits();
+      unsigned IISize = II.StartValue->getType()->getScalarSizeInBits();
+      Value *CRD = CountRoundDown;
+      if (CRDSize > IISize)
+        CRD = CastInst::Create(Instruction::Trunc, CountRoundDown,
+                               II.StartValue->getType(),
+                               "tr.crd", BypassBlock->getTerminator());
+      else if (CRDSize < IISize)
+        CRD = CastInst::Create(Instruction::SExt, CountRoundDown,
+                               II.StartValue->getType(),
+                               "sext.crd", BypassBlock->getTerminator());
+      // Handle reverse integer induction counter:
+      EndValue = BinaryOperator::CreateSub(II.StartValue, CRD, "rev.ind.end",
+                                           BypassBlock->getTerminator());
+      break;
+    }
+    case LoopVectorizationLegality::IK_PtrInduction: {
+      // For pointer induction variables, calculate the offset using
+      // the end index.
+      EndValue = GetElementPtrInst::Create(II.StartValue, CountRoundDown,
+                                           "ptr.ind.end",
+                                           BypassBlock->getTerminator());
+      break;
+    }
+    }// end of case
+
+    // The new PHI merges the original incoming value, in case of a bypass,
+    // or the value at the end of the vectorized loop.
+    ResumeVal->addIncoming(II.StartValue, BypassBlock);
+    ResumeVal->addIncoming(EndValue, VecBody);
+
+    // Fix the scalar body counter (PHI node).
+    unsigned BlockIdx = OrigPhi->getBasicBlockIndex(ScalarPH);
+    OrigPhi->setIncomingValue(BlockIdx, ResumeVal);
+  }
+
+  // If we are generating a new induction variable then we also need to
+  // generate the code that calculates the exit value. This value is not
+  // simply the end of the counter because we may skip the vectorized body
+  // in case of a runtime check.
+  if (!OldInduction){
+    assert(!ResumeIndex && "Unexpected resume value found");
+    ResumeIndex = PHINode::Create(IdxTy, 2, "new.indc.resume.val",
+                                  MiddleBlock->getTerminator());
+    ResumeIndex->addIncoming(StartIdx, BypassBlock);
+    ResumeIndex->addIncoming(IdxEndRoundDown, VecBody);
+  }
+
+  // Make sure that we found the index where scalar loop needs to continue.
+  assert(ResumeIndex && ResumeIndex->getType()->isIntegerTy() &&
+         "Invalid resume Index");
+
+  // Add a check in the middle block to see if we have completed
+  // all of the iterations in the first vector loop.
+  // If (N - N%VF) == N, then we *don't* need to run the remainder.
+  Value *CmpN = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_EQ, IdxEnd,
+                                ResumeIndex, "cmp.n",
+                                MiddleBlock->getTerminator());
+
+  BranchInst::Create(ExitBlock, ScalarPH, CmpN, MiddleBlock->getTerminator());
+  // Remove the old terminator.
+  MiddleBlock->getTerminator()->eraseFromParent();
+
+  // Create i+1 and fill the PHINode.
+  Value *NextIdx = Builder.CreateAdd(Induction, Step, "index.next");
+  Induction->addIncoming(StartIdx, VectorPH);
+  Induction->addIncoming(NextIdx, VecBody);
+  // Create the compare.
+  Value *ICmp = Builder.CreateICmpEQ(NextIdx, IdxEndRoundDown);
+  Builder.CreateCondBr(ICmp, MiddleBlock, VecBody);
+
+  // Now we have two terminators. Remove the old one from the block.
+  VecBody->getTerminator()->eraseFromParent();
+
+  // Get ready to start creating new instructions into the vectorized body.
+  Builder.SetInsertPoint(VecBody->getFirstInsertionPt());
+
+  // Create and register the new vector loop.
+  Loop* Lp = new Loop();
+  Loop *ParentLoop = OrigLoop->getParentLoop();
+
+  // Insert the new loop into the loop nest and register the new basic blocks.
+  if (ParentLoop) {
+    ParentLoop->addChildLoop(Lp);
+    ParentLoop->addBasicBlockToLoop(ScalarPH, LI->getBase());
+    ParentLoop->addBasicBlockToLoop(VectorPH, LI->getBase());
+    ParentLoop->addBasicBlockToLoop(MiddleBlock, LI->getBase());
+  } else {
+    LI->addTopLevelLoop(Lp);
+  }
+
+  Lp->addBasicBlockToLoop(VecBody, LI->getBase());
+
+  // Save the state.
+  LoopVectorPreHeader = VectorPH;
+  LoopScalarPreHeader = ScalarPH;
+  LoopMiddleBlock = MiddleBlock;
+  LoopExitBlock = ExitBlock;
+  LoopVectorBody = VecBody;
+  LoopScalarBody = OldBasicBlock;
+  LoopBypassBlock = BypassBlock;
+}
+
+/// This function returns the identity element (or neutral element) for
+/// the operation K.
+static Constant*
+getReductionIdentity(LoopVectorizationLegality::ReductionKind K, Type *Tp) {
+  switch (K) {
+  case LoopVectorizationLegality:: RK_IntegerXor:
+  case LoopVectorizationLegality:: RK_IntegerAdd:
+  case LoopVectorizationLegality:: RK_IntegerOr:
+    // Adding, Xoring, Oring zero to a number does not change it.
+    return ConstantInt::get(Tp, 0);
+  case LoopVectorizationLegality:: RK_IntegerMult:
+    // Multiplying a number by 1 does not change it.
+    return ConstantInt::get(Tp, 1);
+  case LoopVectorizationLegality:: RK_IntegerAnd:
+    // AND-ing a number with an all-1 value does not change it.
+    return ConstantInt::get(Tp, -1, true);
+  case LoopVectorizationLegality:: RK_FloatMult:
+    // Multiplying a number by 1 does not change it.
+    return ConstantFP::get(Tp, 1.0L);
+  case LoopVectorizationLegality:: RK_FloatAdd:
+    // Adding zero to a number does not change it.
+    return ConstantFP::get(Tp, 0.0L);
+  default:
+    llvm_unreachable("Unknown reduction kind");
+  }
+}
+
+static bool
+isTriviallyVectorizableIntrinsic(Instruction *Inst) {
+  IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst);
+  if (!II)
+    return false;
+  switch (II->getIntrinsicID()) {
+  case Intrinsic::sqrt:
+  case Intrinsic::sin:
+  case Intrinsic::cos:
+  case Intrinsic::exp:
+  case Intrinsic::exp2:
+  case Intrinsic::log:
+  case Intrinsic::log10:
+  case Intrinsic::log2:
+  case Intrinsic::fabs:
+  case Intrinsic::floor:
+  case Intrinsic::ceil:
+  case Intrinsic::trunc:
+  case Intrinsic::rint:
+  case Intrinsic::nearbyint:
+  case Intrinsic::pow:
+  case Intrinsic::fma:
+  case Intrinsic::fmuladd:
+    return true;
+  default:
+    return false;
+  }
+  return false;
+}
+
+/// This function translates the reduction kind to an LLVM binary operator.
+static Instruction::BinaryOps
+getReductionBinOp(LoopVectorizationLegality::ReductionKind Kind) {
+  switch (Kind) {
+    case LoopVectorizationLegality::RK_IntegerAdd:
+      return Instruction::Add;
+    case LoopVectorizationLegality::RK_IntegerMult:
+      return Instruction::Mul;
+    case LoopVectorizationLegality::RK_IntegerOr:
+      return Instruction::Or;
+    case LoopVectorizationLegality::RK_IntegerAnd:
+      return Instruction::And;
+    case LoopVectorizationLegality::RK_IntegerXor:
+      return Instruction::Xor;
+    case LoopVectorizationLegality::RK_FloatMult:
+      return Instruction::FMul;
+    case LoopVectorizationLegality::RK_FloatAdd:
+      return Instruction::FAdd;
+    default:
+      llvm_unreachable("Unknown reduction operation");
+  }
+}
+
+void
+InnerLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) {
+  //===------------------------------------------------===//
+  //
+  // Notice: any optimization or new instruction that go
+  // into the code below should be also be implemented in
+  // the cost-model.
+  //
+  //===------------------------------------------------===//
+  BasicBlock &BB = *OrigLoop->getHeader();
+  Constant *Zero =
+  ConstantInt::get(IntegerType::getInt32Ty(BB.getContext()), 0);
+
+  // In order to support reduction variables we need to be able to vectorize
+  // Phi nodes. Phi nodes have cycles, so we need to vectorize them in two
+  // stages. First, we create a new vector PHI node with no incoming edges.
+  // We use this value when we vectorize all of the instructions that use the
+  // PHI. Next, after all of the instructions in the block are complete we
+  // add the new incoming edges to the PHI. At this point all of the
+  // instructions in the basic block are vectorized, so we can use them to
+  // construct the PHI.
+  PhiVector RdxPHIsToFix;
+
+  // Scan the loop in a topological order to ensure that defs are vectorized
+  // before users.
+  LoopBlocksDFS DFS(OrigLoop);
+  DFS.perform(LI);
+
+  // Vectorize all of the blocks in the original loop.
+  for (LoopBlocksDFS::RPOIterator bb = DFS.beginRPO(),
+       be = DFS.endRPO(); bb != be; ++bb)
+    vectorizeBlockInLoop(Legal, *bb, &RdxPHIsToFix);
+
+  // At this point every instruction in the original loop is widened to
+  // a vector form. We are almost done. Now, we need to fix the PHI nodes
+  // that we vectorized. The PHI nodes are currently empty because we did
+  // not want to introduce cycles. Notice that the remaining PHI nodes
+  // that we need to fix are reduction variables.
+
+  // Create the 'reduced' values for each of the induction vars.
+  // The reduced values are the vector values that we scalarize and combine
+  // after the loop is finished.
+  for (PhiVector::iterator it = RdxPHIsToFix.begin(), e = RdxPHIsToFix.end();
+       it != e; ++it) {
+    PHINode *RdxPhi = *it;
+    assert(RdxPhi && "Unable to recover vectorized PHI");
+
+    // Find the reduction variable descriptor.
+    assert(Legal->getReductionVars()->count(RdxPhi) &&
+           "Unable to find the reduction variable");
+    LoopVectorizationLegality::ReductionDescriptor RdxDesc =
+    (*Legal->getReductionVars())[RdxPhi];
+
+    // We need to generate a reduction vector from the incoming scalar.
+    // To do so, we need to generate the 'identity' vector and overide
+    // one of the elements with the incoming scalar reduction. We need
+    // to do it in the vector-loop preheader.
+    Builder.SetInsertPoint(LoopBypassBlock->getTerminator());
+
+    // This is the vector-clone of the value that leaves the loop.
+    VectorParts &VectorExit = getVectorValue(RdxDesc.LoopExitInstr);
+    Type *VecTy = VectorExit[0]->getType();
+
+    // Find the reduction identity variable. Zero for addition, or, xor,
+    // one for multiplication, -1 for And.
+    Constant *Iden = getReductionIdentity(RdxDesc.Kind, VecTy->getScalarType());
+    Constant *Identity = ConstantVector::getSplat(VF, Iden);
+
+    // This vector is the Identity vector where the first element is the
+    // incoming scalar reduction.
+    Value *VectorStart = Builder.CreateInsertElement(Identity,
+                                                     RdxDesc.StartValue, Zero);
+
+    // Fix the vector-loop phi.
+    // We created the induction variable so we know that the
+    // preheader is the first entry.
+    BasicBlock *VecPreheader = Induction->getIncomingBlock(0);
+
+    // Reductions do not have to start at zero. They can start with
+    // any loop invariant values.
+    VectorParts &VecRdxPhi = WidenMap.get(RdxPhi);
+    BasicBlock *Latch = OrigLoop->getLoopLatch();
+    Value *LoopVal = RdxPhi->getIncomingValueForBlock(Latch);
+    VectorParts &Val = getVectorValue(LoopVal);
+    for (unsigned part = 0; part < UF; ++part) {
+      // Make sure to add the reduction stat value only to the 
+      // first unroll part.
+      Value *StartVal = (part == 0) ? VectorStart : Identity;
+      cast<PHINode>(VecRdxPhi[part])->addIncoming(StartVal, VecPreheader);
+      cast<PHINode>(VecRdxPhi[part])->addIncoming(Val[part], LoopVectorBody);
+    }
+
+    // Before each round, move the insertion point right between
+    // the PHIs and the values we are going to write.
+    // This allows us to write both PHINodes and the extractelement
+    // instructions.
+    Builder.SetInsertPoint(LoopMiddleBlock->getFirstInsertionPt());
+
+    VectorParts RdxParts;
+    for (unsigned part = 0; part < UF; ++part) {
+      // This PHINode contains the vectorized reduction variable, or
+      // the initial value vector, if we bypass the vector loop.
+      VectorParts &RdxExitVal = getVectorValue(RdxDesc.LoopExitInstr);
+      PHINode *NewPhi = Builder.CreatePHI(VecTy, 2, "rdx.vec.exit.phi");
+      Value *StartVal = (part == 0) ? VectorStart : Identity;
+      NewPhi->addIncoming(StartVal, LoopBypassBlock);
+      NewPhi->addIncoming(RdxExitVal[part], LoopVectorBody);
+      RdxParts.push_back(NewPhi);
+    }
+
+    // Reduce all of the unrolled parts into a single vector.
+    Value *ReducedPartRdx = RdxParts[0];
+    for (unsigned part = 1; part < UF; ++part) {
+      Instruction::BinaryOps Op = getReductionBinOp(RdxDesc.Kind);
+      ReducedPartRdx = Builder.CreateBinOp(Op, RdxParts[part], ReducedPartRdx,
+                                           "bin.rdx");
+    }
+
+    // VF is a power of 2 so we can emit the reduction using log2(VF) shuffles
+    // and vector ops, reducing the set of values being computed by half each
+    // round.
+    assert(isPowerOf2_32(VF) &&
+           "Reduction emission only supported for pow2 vectors!");
+    Value *TmpVec = ReducedPartRdx;
+    SmallVector<Constant*, 32> ShuffleMask(VF, 0);
+    for (unsigned i = VF; i != 1; i >>= 1) {
+      // Move the upper half of the vector to the lower half.
+      for (unsigned j = 0; j != i/2; ++j)
+        ShuffleMask[j] = Builder.getInt32(i/2 + j);
+
+      // Fill the rest of the mask with undef.
+      std::fill(&ShuffleMask[i/2], ShuffleMask.end(),
+                UndefValue::get(Builder.getInt32Ty()));
+
+      Value *Shuf =
+        Builder.CreateShuffleVector(TmpVec,
+                                    UndefValue::get(TmpVec->getType()),
+                                    ConstantVector::get(ShuffleMask),
+                                    "rdx.shuf");
+
+      Instruction::BinaryOps Op = getReductionBinOp(RdxDesc.Kind);
+      TmpVec = Builder.CreateBinOp(Op, TmpVec, Shuf, "bin.rdx");
+    }
+
+    // The result is in the first element of the vector.
+    Value *Scalar0 = Builder.CreateExtractElement(TmpVec, Builder.getInt32(0));
+
+    // Now, we need to fix the users of the reduction variable
+    // inside and outside of the scalar remainder loop.
+    // We know that the loop is in LCSSA form. We need to update the
+    // PHI nodes in the exit blocks.
+    for (BasicBlock::iterator LEI = LoopExitBlock->begin(),
+         LEE = LoopExitBlock->end(); LEI != LEE; ++LEI) {
+      PHINode *LCSSAPhi = dyn_cast<PHINode>(LEI);
+      if (!LCSSAPhi) continue;
+
+      // All PHINodes need to have a single entry edge, or two if
+      // we already fixed them.
+      assert(LCSSAPhi->getNumIncomingValues() < 3 && "Invalid LCSSA PHI");
+
+      // We found our reduction value exit-PHI. Update it with the
+      // incoming bypass edge.
+      if (LCSSAPhi->getIncomingValue(0) == RdxDesc.LoopExitInstr) {
+        // Add an edge coming from the bypass.
+        LCSSAPhi->addIncoming(Scalar0, LoopMiddleBlock);
+        break;
+      }
+    }// end of the LCSSA phi scan.
+
+    // Fix the scalar loop reduction variable with the incoming reduction sum
+    // from the vector body and from the backedge value.
+    int IncomingEdgeBlockIdx =
+    (RdxPhi)->getBasicBlockIndex(OrigLoop->getLoopLatch());
+    assert(IncomingEdgeBlockIdx >= 0 && "Invalid block index");
+    // Pick the other block.
+    int SelfEdgeBlockIdx = (IncomingEdgeBlockIdx ? 0 : 1);
+    (RdxPhi)->setIncomingValue(SelfEdgeBlockIdx, Scalar0);
+    (RdxPhi)->setIncomingValue(IncomingEdgeBlockIdx, RdxDesc.LoopExitInstr);
+  }// end of for each redux variable.
+
+  // The Loop exit block may have single value PHI nodes where the incoming
+  // value is 'undef'. While vectorizing we only handled real values that
+  // were defined inside the loop. Here we handle the 'undef case'.
+  // See PR14725.
+  for (BasicBlock::iterator LEI = LoopExitBlock->begin(),
+       LEE = LoopExitBlock->end(); LEI != LEE; ++LEI) {
+    PHINode *LCSSAPhi = dyn_cast<PHINode>(LEI);
+    if (!LCSSAPhi) continue;
+    if (LCSSAPhi->getNumIncomingValues() == 1)
+      LCSSAPhi->addIncoming(UndefValue::get(LCSSAPhi->getType()),
+                            LoopMiddleBlock);
+  }
+}
+
+InnerLoopVectorizer::VectorParts
+InnerLoopVectorizer::createEdgeMask(BasicBlock *Src, BasicBlock *Dst) {
+  assert(std::find(pred_begin(Dst), pred_end(Dst), Src) != pred_end(Dst) &&
+         "Invalid edge");
+
+  VectorParts SrcMask = createBlockInMask(Src);
+
+  // The terminator has to be a branch inst!
+  BranchInst *BI = dyn_cast<BranchInst>(Src->getTerminator());
+  assert(BI && "Unexpected terminator found");
+
+  if (BI->isConditional()) {
+    VectorParts EdgeMask = getVectorValue(BI->getCondition());
+
+    if (BI->getSuccessor(0) != Dst)
+      for (unsigned part = 0; part < UF; ++part)
+        EdgeMask[part] = Builder.CreateNot(EdgeMask[part]);
+
+    for (unsigned part = 0; part < UF; ++part)
+      EdgeMask[part] = Builder.CreateAnd(EdgeMask[part], SrcMask[part]);
+    return EdgeMask;
+  }
+
+  return SrcMask;
+}
+
+InnerLoopVectorizer::VectorParts
+InnerLoopVectorizer::createBlockInMask(BasicBlock *BB) {
+  assert(OrigLoop->contains(BB) && "Block is not a part of a loop");
+
+  // Loop incoming mask is all-one.
+  if (OrigLoop->getHeader() == BB) {
+    Value *C = ConstantInt::get(IntegerType::getInt1Ty(BB->getContext()), 1);
+    return getVectorValue(C);
+  }
+
+  // This is the block mask. We OR all incoming edges, and with zero.
+  Value *Zero = ConstantInt::get(IntegerType::getInt1Ty(BB->getContext()), 0);
+  VectorParts BlockMask = getVectorValue(Zero);
+
+  // For each pred:
+  for (pred_iterator it = pred_begin(BB), e = pred_end(BB); it != e; ++it) {
+    VectorParts EM = createEdgeMask(*it, BB);
+    for (unsigned part = 0; part < UF; ++part)
+      BlockMask[part] = Builder.CreateOr(BlockMask[part], EM[part]);
+  }
+
+  return BlockMask;
+}
+
+void
+InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal,
+                                          BasicBlock *BB, PhiVector *PV) {
+  Constant *Zero = Builder.getInt32(0);
+
+  // For each instruction in the old loop.
+  for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) {
+    VectorParts &Entry = WidenMap.get(it);
+    switch (it->getOpcode()) {
+    case Instruction::Br:
+      // Nothing to do for PHIs and BR, since we already took care of the
+      // loop control flow instructions.
+      continue;
+    case Instruction::PHI:{
+      PHINode* P = cast<PHINode>(it);
+      // Handle reduction variables:
+      if (Legal->getReductionVars()->count(P)) {
+        for (unsigned part = 0; part < UF; ++part) {
+          // This is phase one of vectorizing PHIs.
+          Type *VecTy = VectorType::get(it->getType(), VF);
+          Entry[part] = PHINode::Create(VecTy, 2, "vec.phi",
+                                        LoopVectorBody-> getFirstInsertionPt());
+        }
+        PV->push_back(P);
+        continue;
+      }
+
+      // Check for PHI nodes that are lowered to vector selects.
+      if (P->getParent() != OrigLoop->getHeader()) {
+        // We know that all PHIs in non header blocks are converted into
+        // selects, so we don't have to worry about the insertion order and we
+        // can just use the builder.
+
+        // At this point we generate the predication tree. There may be
+        // duplications since this is a simple recursive scan, but future
+        // optimizations will clean it up.
+        VectorParts Cond = createEdgeMask(P->getIncomingBlock(0),
+                                               P->getParent());
+        
+        for (unsigned part = 0; part < UF; ++part) {
+        VectorParts &In0 = getVectorValue(P->getIncomingValue(0));
+        VectorParts &In1 = getVectorValue(P->getIncomingValue(1));
+          Entry[part] = Builder.CreateSelect(Cond[part], In0[part], In1[part],
+                                             "predphi");
+        }
+        continue;
+      }
+
+      // This PHINode must be an induction variable.
+      // Make sure that we know about it.
+      assert(Legal->getInductionVars()->count(P) &&
+             "Not an induction variable");
+
+      LoopVectorizationLegality::InductionInfo II =
+        Legal->getInductionVars()->lookup(P);
+
+      switch (II.IK) {
+      case LoopVectorizationLegality::IK_NoInduction:
+        llvm_unreachable("Unknown induction");
+      case LoopVectorizationLegality::IK_IntInduction: {
+        assert(P == OldInduction && "Unexpected PHI");
+        Value *Broadcasted = getBroadcastInstrs(Induction);
+        // After broadcasting the induction variable we need to make the
+        // vector consecutive by adding 0, 1, 2 ...
+        for (unsigned part = 0; part < UF; ++part)
+          Entry[part] = getConsecutiveVector(Broadcasted, VF * part, false);
+        continue;
+      }
+      case LoopVectorizationLegality::IK_ReverseIntInduction:
+      case LoopVectorizationLegality::IK_PtrInduction:
+        // Handle reverse integer and pointer inductions.
+        Value *StartIdx = 0;
+        // If we have a single integer induction variable then use it.
+        // Otherwise, start counting at zero.
+        if (OldInduction) {
+          LoopVectorizationLegality::InductionInfo OldII =
+            Legal->getInductionVars()->lookup(OldInduction);
+          StartIdx = OldII.StartValue;
+        } else {
+          StartIdx = ConstantInt::get(Induction->getType(), 0);
+        }
+        // This is the normalized GEP that starts counting at zero.
+        Value *NormalizedIdx = Builder.CreateSub(Induction, StartIdx,
+                                                 "normalized.idx");
+
+        // Handle the reverse integer induction variable case.
+        if (LoopVectorizationLegality::IK_ReverseIntInduction == II.IK) {
+          IntegerType *DstTy = cast<IntegerType>(II.StartValue->getType());
+          Value *CNI = Builder.CreateSExtOrTrunc(NormalizedIdx, DstTy,
+                                                 "resize.norm.idx");
+          Value *ReverseInd  = Builder.CreateSub(II.StartValue, CNI,
+                                                 "reverse.idx");
+
+          // This is a new value so do not hoist it out.
+          Value *Broadcasted = getBroadcastInstrs(ReverseInd);
+          // After broadcasting the induction variable we need to make the
+          // vector consecutive by adding  ... -3, -2, -1, 0.
+          for (unsigned part = 0; part < UF; ++part)
+            Entry[part] = getConsecutiveVector(Broadcasted, -VF * part, true);
+          continue;
+        }
+
+        // Handle the pointer induction variable case.
+        assert(P->getType()->isPointerTy() && "Unexpected type.");
+
+        // This is the vector of results. Notice that we don't generate
+        // vector geps because scalar geps result in better code.
+        for (unsigned part = 0; part < UF; ++part) {
+          Value *VecVal = UndefValue::get(VectorType::get(P->getType(), VF));
+          for (unsigned int i = 0; i < VF; ++i) {
+            Constant *Idx = ConstantInt::get(Induction->getType(),
+                                             i + part * VF);
+            Value *GlobalIdx = Builder.CreateAdd(NormalizedIdx, Idx,
+                                                 "gep.idx");
+            Value *SclrGep = Builder.CreateGEP(II.StartValue, GlobalIdx,
+                                               "next.gep");
+            VecVal = Builder.CreateInsertElement(VecVal, SclrGep,
+                                                 Builder.getInt32(i),
+                                                 "insert.gep");
+          }
+          Entry[part] = VecVal;
+        }
+        continue;
+      }
+
+    }// End of PHI.
+
+    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: {
+      // Just widen binops.
+      BinaryOperator *BinOp = dyn_cast<BinaryOperator>(it);
+      VectorParts &A = getVectorValue(it->getOperand(0));
+      VectorParts &B = getVectorValue(it->getOperand(1));
+
+      // Use this vector value for all users of the original instruction.
+      for (unsigned Part = 0; Part < UF; ++Part) {
+        Value *V = Builder.CreateBinOp(BinOp->getOpcode(), A[Part], B[Part]);
+
+        // Update the NSW, NUW and Exact flags.
+        BinaryOperator *VecOp = cast<BinaryOperator>(V);
+        if (isa<OverflowingBinaryOperator>(BinOp)) {
+          VecOp->setHasNoSignedWrap(BinOp->hasNoSignedWrap());
+          VecOp->setHasNoUnsignedWrap(BinOp->hasNoUnsignedWrap());
+        }
+        if (isa<PossiblyExactOperator>(VecOp))
+          VecOp->setIsExact(BinOp->isExact());
+
+        Entry[Part] = V;
+      }
+      break;
+    }
+    case Instruction::Select: {
+      // Widen selects.
+      // If the selector is loop invariant we can create a select
+      // instruction with a scalar condition. Otherwise, use vector-select.
+      bool InvariantCond = SE->isLoopInvariant(SE->getSCEV(it->getOperand(0)),
+                                               OrigLoop);
+
+      // The condition can be loop invariant  but still defined inside the
+      // loop. This means that we can't just use the original 'cond' value.
+      // We have to take the 'vectorized' value and pick the first lane.
+      // Instcombine will make this a no-op.
+      VectorParts &Cond = getVectorValue(it->getOperand(0));
+      VectorParts &Op0  = getVectorValue(it->getOperand(1));
+      VectorParts &Op1  = getVectorValue(it->getOperand(2));
+      Value *ScalarCond = Builder.CreateExtractElement(Cond[0],
+                                                       Builder.getInt32(0));
+      for (unsigned Part = 0; Part < UF; ++Part) {
+        Entry[Part] = Builder.CreateSelect(
+          InvariantCond ? ScalarCond : Cond[Part],
+          Op0[Part],
+          Op1[Part]);
+      }
+      break;
+    }
+
+    case Instruction::ICmp:
+    case Instruction::FCmp: {
+      // Widen compares. Generate vector compares.
+      bool FCmp = (it->getOpcode() == Instruction::FCmp);
+      CmpInst *Cmp = dyn_cast<CmpInst>(it);
+      VectorParts &A = getVectorValue(it->getOperand(0));
+      VectorParts &B = getVectorValue(it->getOperand(1));
+      for (unsigned Part = 0; Part < UF; ++Part) {
+        Value *C = 0;
+        if (FCmp)
+          C = Builder.CreateFCmp(Cmp->getPredicate(), A[Part], B[Part]);
+        else
+          C = Builder.CreateICmp(Cmp->getPredicate(), A[Part], B[Part]);
+        Entry[Part] = C;
+      }
+      break;
+    }
+
+    case Instruction::Store: {
+      // Attempt to issue a wide store.
+      StoreInst *SI = dyn_cast<StoreInst>(it);
+      Type *StTy = VectorType::get(SI->getValueOperand()->getType(), VF);
+      Value *Ptr = SI->getPointerOperand();
+      unsigned Alignment = SI->getAlignment();
+
+      assert(!Legal->isUniform(Ptr) &&
+             "We do not allow storing to uniform addresses");
+
+
+      int Stride = Legal->isConsecutivePtr(Ptr);
+      bool Reverse = Stride < 0;
+      if (Stride == 0) {
+        scalarizeInstruction(it);
+        break;
+      }
+
+      // Handle consecutive stores.
+
+      GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
+      if (Gep) {
+        // The last index does not have to be the induction. It can be
+        // consecutive and be a function of the index. For example A[I+1];
+        unsigned NumOperands = Gep->getNumOperands();
+
+        Value *LastGepOperand = Gep->getOperand(NumOperands - 1);
+        VectorParts &GEPParts = getVectorValue(LastGepOperand);
+        Value *LastIndex = GEPParts[0];
+        LastIndex = Builder.CreateExtractElement(LastIndex, Zero);
+
+        // Create the new GEP with the new induction variable.
+        GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone());
+        Gep2->setOperand(NumOperands - 1, LastIndex);
+        Ptr = Builder.Insert(Gep2);
+      } else {
+        // Use the induction element ptr.
+        assert(isa<PHINode>(Ptr) && "Invalid induction ptr");
+        VectorParts &PtrVal = getVectorValue(Ptr);
+        Ptr = Builder.CreateExtractElement(PtrVal[0], Zero);
+      }
+
+      VectorParts &StoredVal = getVectorValue(SI->getValueOperand());
+      for (unsigned Part = 0; Part < UF; ++Part) {
+        // Calculate the pointer for the specific unroll-part.
+        Value *PartPtr = Builder.CreateGEP(Ptr, Builder.getInt32(Part * VF));
+
+        if (Reverse) {
+          // If we store to reverse consecutive memory locations then we need
+          // to reverse the order of elements in the stored value.
+          StoredVal[Part] = reverseVector(StoredVal[Part]);
+          // If the address is consecutive but reversed, then the
+          // wide store needs to start at the last vector element.
+          PartPtr = Builder.CreateGEP(Ptr, Builder.getInt32(-Part * VF));
+          PartPtr = Builder.CreateGEP(PartPtr, Builder.getInt32(1 - VF));
+        }
+
+        Value *VecPtr = Builder.CreateBitCast(PartPtr, StTy->getPointerTo());
+        Builder.CreateStore(StoredVal[Part], VecPtr)->setAlignment(Alignment);
+      }
+      break;
+    }
+    case Instruction::Load: {
+      // Attempt to issue a wide load.
+      LoadInst *LI = dyn_cast<LoadInst>(it);
+      Type *RetTy = VectorType::get(LI->getType(), VF);
+      Value *Ptr = LI->getPointerOperand();
+      unsigned Alignment = LI->getAlignment();
+
+      // If the pointer is loop invariant or if it is non consecutive,
+      // scalarize the load.
+      int Stride = Legal->isConsecutivePtr(Ptr);
+      bool Reverse = Stride < 0;
+      if (Legal->isUniform(Ptr) || Stride == 0) {
+        scalarizeInstruction(it);
+        break;
+      }
+
+      GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
+      if (Gep) {
+        // The last index does not have to be the induction. It can be
+        // consecutive and be a function of the index. For example A[I+1];
+        unsigned NumOperands = Gep->getNumOperands();
+
+        Value *LastGepOperand = Gep->getOperand(NumOperands - 1);
+        VectorParts &GEPParts = getVectorValue(LastGepOperand);
+        Value *LastIndex = GEPParts[0];
+        LastIndex = Builder.CreateExtractElement(LastIndex, Zero);
+
+        // Create the new GEP with the new induction variable.
+        GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone());
+        Gep2->setOperand(NumOperands - 1, LastIndex);
+        Ptr = Builder.Insert(Gep2);
+      } else {
+        // Use the induction element ptr.
+        assert(isa<PHINode>(Ptr) && "Invalid induction ptr");
+        VectorParts &PtrVal = getVectorValue(Ptr);
+        Ptr = Builder.CreateExtractElement(PtrVal[0], Zero);
+      }
+
+      for (unsigned Part = 0; Part < UF; ++Part) {
+        // Calculate the pointer for the specific unroll-part.
+        Value *PartPtr = Builder.CreateGEP(Ptr, Builder.getInt32(Part * VF));
+
+        if (Reverse) {
+          // If the address is consecutive but reversed, then the
+          // wide store needs to start at the last vector element.
+          PartPtr = Builder.CreateGEP(Ptr, Builder.getInt32(-Part * VF));
+          PartPtr = Builder.CreateGEP(PartPtr, Builder.getInt32(1 - VF));
+        }
+
+        Value *VecPtr = Builder.CreateBitCast(PartPtr, RetTy->getPointerTo());
+        Value *LI = Builder.CreateLoad(VecPtr, "wide.load");
+        cast<LoadInst>(LI)->setAlignment(Alignment);
+        Entry[Part] = Reverse ? reverseVector(LI) :  LI;
+      }
+      break;
+    }
+    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: {
+      CastInst *CI = dyn_cast<CastInst>(it);
+      /// Optimize the special case where the source is the induction
+      /// variable. Notice that we can only optimize the 'trunc' case
+      /// because: a. FP conversions lose precision, b. sext/zext may wrap,
+      /// c. other casts depend on pointer size.
+      if (CI->getOperand(0) == OldInduction &&
+          it->getOpcode() == Instruction::Trunc) {
+        Value *ScalarCast = Builder.CreateCast(CI->getOpcode(), Induction,
+                                               CI->getType());
+        Value *Broadcasted = getBroadcastInstrs(ScalarCast);
+        for (unsigned Part = 0; Part < UF; ++Part)
+          Entry[Part] = getConsecutiveVector(Broadcasted, VF * Part, false);
+        break;
+      }
+      /// Vectorize casts.
+      Type *DestTy = VectorType::get(CI->getType()->getScalarType(), VF);
+
+      VectorParts &A = getVectorValue(it->getOperand(0));
+      for (unsigned Part = 0; Part < UF; ++Part)
+        Entry[Part] = Builder.CreateCast(CI->getOpcode(), A[Part], DestTy);
+      break;
+    }
+
+    case Instruction::Call: {
+      assert(isTriviallyVectorizableIntrinsic(it));
+      Module *M = BB->getParent()->getParent();
+      IntrinsicInst *II = cast<IntrinsicInst>(it);
+      Intrinsic::ID ID = II->getIntrinsicID();
+      for (unsigned Part = 0; Part < UF; ++Part) {
+        SmallVector<Value*, 4> Args;
+        for (unsigned i = 0, ie = II->getNumArgOperands(); i != ie; ++i) {
+          VectorParts &Arg = getVectorValue(II->getArgOperand(i));
+          Args.push_back(Arg[Part]);
+        }
+        Type *Tys[] = { VectorType::get(II->getType()->getScalarType(), VF) };
+        Function *F = Intrinsic::getDeclaration(M, ID, Tys);
+        Entry[Part] = Builder.CreateCall(F, Args);
+      }
+      break;
+    }
+
+    default:
+      // All other instructions are unsupported. Scalarize them.
+      scalarizeInstruction(it);
+      break;
+    }// end of switch.
+  }// end of for_each instr.
+}
+
+void InnerLoopVectorizer::updateAnalysis() {
+  // Forget the original basic block.
+  SE->forgetLoop(OrigLoop);
+
+  // Update the dominator tree information.
+  assert(DT->properlyDominates(LoopBypassBlock, LoopExitBlock) &&
+         "Entry does not dominate exit.");
+
+  DT->addNewBlock(LoopVectorPreHeader, LoopBypassBlock);
+  DT->addNewBlock(LoopVectorBody, LoopVectorPreHeader);
+  DT->addNewBlock(LoopMiddleBlock, LoopBypassBlock);
+  DT->addNewBlock(LoopScalarPreHeader, LoopMiddleBlock);
+  DT->changeImmediateDominator(LoopScalarBody, LoopScalarPreHeader);
+  DT->changeImmediateDominator(LoopExitBlock, LoopMiddleBlock);
+
+  DEBUG(DT->verifyAnalysis());
+}
+
+bool LoopVectorizationLegality::canVectorizeWithIfConvert() {
+  if (!EnableIfConversion)
+    return false;
+
+  assert(TheLoop->getNumBlocks() > 1 && "Single block loops are vectorizable");
+  std::vector<BasicBlock*> &LoopBlocks = TheLoop->getBlocksVector();
+
+  // Collect the blocks that need predication.
+  for (unsigned i = 0, e = LoopBlocks.size(); i < e; ++i) {
+    BasicBlock *BB = LoopBlocks[i];
+
+    // We don't support switch statements inside loops.
+    if (!isa<BranchInst>(BB->getTerminator()))
+      return false;
+
+    // We must have at most two predecessors because we need to convert
+    // all PHIs to selects.
+    unsigned Preds = std::distance(pred_begin(BB), pred_end(BB));
+    if (Preds > 2)
+      return false;
+
+    // We must be able to predicate all blocks that need to be predicated.
+    if (blockNeedsPredication(BB) && !blockCanBePredicated(BB))
+      return false;
+  }
+
+  // We can if-convert this loop.
+  return true;
+}
+
+bool LoopVectorizationLegality::canVectorize() {
+  assert(TheLoop->getLoopPreheader() && "No preheader!!");
+
+  // We can only vectorize innermost loops.
+  if (TheLoop->getSubLoopsVector().size())
+    return false;
+
+  // We must have a single backedge.
+  if (TheLoop->getNumBackEdges() != 1)
+    return false;
+
+  // We must have a single exiting block.
+  if (!TheLoop->getExitingBlock())
+    return false;
+
+  unsigned NumBlocks = TheLoop->getNumBlocks();
+
+  // Check if we can if-convert non single-bb loops.
+  if (NumBlocks != 1 && !canVectorizeWithIfConvert()) {
+    DEBUG(dbgs() << "LV: Can't if-convert the loop.\n");
+    return false;
+  }
+
+  // We need to have a loop header.
+  BasicBlock *Latch = TheLoop->getLoopLatch();
+  DEBUG(dbgs() << "LV: Found a loop: " <<
+        TheLoop->getHeader()->getName() << "\n");
+
+  // ScalarEvolution needs to be able to find the exit count.
+  const SCEV *ExitCount = SE->getExitCount(TheLoop, Latch);
+  if (ExitCount == SE->getCouldNotCompute()) {
+    DEBUG(dbgs() << "LV: SCEV could not compute the loop exit count.\n");
+    return false;
+  }
+
+  // Do not loop-vectorize loops with a tiny trip count.
+  unsigned TC = SE->getSmallConstantTripCount(TheLoop, Latch);
+  if (TC > 0u && TC < TinyTripCountVectorThreshold) {
+    DEBUG(dbgs() << "LV: Found a loop with a very small trip count. " <<
+          "This loop is not worth vectorizing.\n");
+    return false;
+  }
+
+  // Check if we can vectorize the instructions and CFG in this loop.
+  if (!canVectorizeInstrs()) {
+    DEBUG(dbgs() << "LV: Can't vectorize the instructions or CFG\n");
+    return false;
+  }
+
+  // Go over each instruction and look at memory deps.
+  if (!canVectorizeMemory()) {
+    DEBUG(dbgs() << "LV: Can't vectorize due to memory conflicts\n");
+    return false;
+  }
+
+  // Collect all of the variables that remain uniform after vectorization.
+  collectLoopUniforms();
+
+  DEBUG(dbgs() << "LV: We can vectorize this loop" <<
+        (PtrRtCheck.Need ? " (with a runtime bound check)" : "")
+        <<"!\n");
+
+  // Okay! We can vectorize. At this point we don't have any other mem analysis
+  // which may limit our maximum vectorization factor, so just return true with
+  // no restrictions.
+  return true;
+}
+
+bool LoopVectorizationLegality::canVectorizeInstrs() {
+  BasicBlock *PreHeader = TheLoop->getLoopPreheader();
+  BasicBlock *Header = TheLoop->getHeader();
+
+  // For each block in the loop.
+  for (Loop::block_iterator bb = TheLoop->block_begin(),
+       be = TheLoop->block_end(); bb != be; ++bb) {
+
+    // Scan the instructions in the block and look for hazards.
+    for (BasicBlock::iterator it = (*bb)->begin(), e = (*bb)->end(); it != e;
+         ++it) {
+
+      if (PHINode *Phi = dyn_cast<PHINode>(it)) {
+        // This should not happen because the loop should be normalized.
+        if (Phi->getNumIncomingValues() != 2) {
+          DEBUG(dbgs() << "LV: Found an invalid PHI.\n");
+          return false;
+        }
+
+        // Check that this PHI type is allowed.
+        if (!Phi->getType()->isIntegerTy() &&
+            !Phi->getType()->isFloatingPointTy() &&
+            !Phi->getType()->isPointerTy()) {
+          DEBUG(dbgs() << "LV: Found an non-int non-pointer PHI.\n");
+          return false;
+        }
+
+        // If this PHINode is not in the header block, then we know that we
+        // can convert it to select during if-conversion. No need to check if
+        // the PHIs in this block are induction or reduction variables.
+        if (*bb != Header)
+          continue;
+
+        // This is the value coming from the preheader.
+        Value *StartValue = Phi->getIncomingValueForBlock(PreHeader);
+        // Check if this is an induction variable.
+        InductionKind IK = isInductionVariable(Phi);
+
+        if (IK_NoInduction != IK) {
+          // Int inductions are special because we only allow one IV.
+          if (IK == IK_IntInduction) {
+            if (Induction) {
+              DEBUG(dbgs() << "LV: Found too many inductions."<< *Phi <<"\n");
+              return false;
+            }
+            Induction = Phi;
+          }
+
+          DEBUG(dbgs() << "LV: Found an induction variable.\n");
+          Inductions[Phi] = InductionInfo(StartValue, IK);
+          continue;
+        }
+
+        if (AddReductionVar(Phi, RK_IntegerAdd)) {
+          DEBUG(dbgs() << "LV: Found an ADD reduction PHI."<< *Phi <<"\n");
+          continue;
+        }
+        if (AddReductionVar(Phi, RK_IntegerMult)) {
+          DEBUG(dbgs() << "LV: Found a MUL reduction PHI."<< *Phi <<"\n");
+          continue;
+        }
+        if (AddReductionVar(Phi, RK_IntegerOr)) {
+          DEBUG(dbgs() << "LV: Found an OR reduction PHI."<< *Phi <<"\n");
+          continue;
+        }
+        if (AddReductionVar(Phi, RK_IntegerAnd)) {
+          DEBUG(dbgs() << "LV: Found an AND reduction PHI."<< *Phi <<"\n");
+          continue;
+        }
+        if (AddReductionVar(Phi, RK_IntegerXor)) {
+          DEBUG(dbgs() << "LV: Found a XOR reduction PHI."<< *Phi <<"\n");
+          continue;
+        }
+        if (AddReductionVar(Phi, RK_FloatMult)) {
+          DEBUG(dbgs() << "LV: Found an FMult reduction PHI."<< *Phi <<"\n");
+          continue;
+        }
+        if (AddReductionVar(Phi, RK_FloatAdd)) {
+          DEBUG(dbgs() << "LV: Found an FAdd reduction PHI."<< *Phi <<"\n");
+          continue;
+        }
+
+        DEBUG(dbgs() << "LV: Found an unidentified PHI."<< *Phi <<"\n");
+        return false;
+      }// end of PHI handling
+
+      // We still don't handle functions.
+      CallInst *CI = dyn_cast<CallInst>(it);
+      if (CI && !isTriviallyVectorizableIntrinsic(it)) {
+        DEBUG(dbgs() << "LV: Found a call site.\n");
+        return false;
+      }
+
+      // Check that the instruction return type is vectorizable.
+      if (!VectorType::isValidElementType(it->getType()) &&
+          !it->getType()->isVoidTy()) {
+        DEBUG(dbgs() << "LV: Found unvectorizable type." << "\n");
+        return false;
+      }
+
+      // Check that the stored type is vectorizable.
+      if (StoreInst *ST = dyn_cast<StoreInst>(it)) {
+        Type *T = ST->getValueOperand()->getType();
+        if (!VectorType::isValidElementType(T))
+          return false;
+      }
+
+      // Reduction instructions are allowed to have exit users.
+      // All other instructions must not have external users.
+      if (!AllowedExit.count(it))
+        //Check that all of the users of the loop are inside the BB.
+        for (Value::use_iterator I = it->use_begin(), E = it->use_end();
+             I != E; ++I) {
+          Instruction *U = cast<Instruction>(*I);
+          // This user may be a reduction exit value.
+          if (!TheLoop->contains(U)) {
+            DEBUG(dbgs() << "LV: Found an outside user for : "<< *U << "\n");
+            return false;
+          }
+        }
+    } // next instr.
+
+  }
+
+  if (!Induction) {
+    DEBUG(dbgs() << "LV: Did not find one integer induction var.\n");
+    assert(getInductionVars()->size() && "No induction variables");
+  }
+
+  return true;
+}
+
+void LoopVectorizationLegality::collectLoopUniforms() {
+  // We now know that the loop is vectorizable!
+  // Collect variables that will remain uniform after vectorization.
+  std::vector<Value*> Worklist;
+  BasicBlock *Latch = TheLoop->getLoopLatch();
+
+  // Start with the conditional branch and walk up the block.
+  Worklist.push_back(Latch->getTerminator()->getOperand(0));
+
+  while (Worklist.size()) {
+    Instruction *I = dyn_cast<Instruction>(Worklist.back());
+    Worklist.pop_back();
+
+    // Look at instructions inside this loop.
+    // Stop when reaching PHI nodes.
+    // TODO: we need to follow values all over the loop, not only in this block.
+    if (!I || !TheLoop->contains(I) || isa<PHINode>(I))
+      continue;
+
+    // This is a known uniform.
+    Uniforms.insert(I);
+
+    // Insert all operands.
+    for (int i = 0, Op = I->getNumOperands(); i < Op; ++i) {
+      Worklist.push_back(I->getOperand(i));
+    }
+  }
+}
+
+bool LoopVectorizationLegality::canVectorizeMemory() {
+  typedef SmallVector<Value*, 16> ValueVector;
+  typedef SmallPtrSet<Value*, 16> ValueSet;
+  // Holds the Load and Store *instructions*.
+  ValueVector Loads;
+  ValueVector Stores;
+  PtrRtCheck.Pointers.clear();
+  PtrRtCheck.Need = false;
+
+  // For each block.
+  for (Loop::block_iterator bb = TheLoop->block_begin(),
+       be = TheLoop->block_end(); bb != be; ++bb) {
+
+    // Scan the BB and collect legal loads and stores.
+    for (BasicBlock::iterator it = (*bb)->begin(), e = (*bb)->end(); it != e;
+         ++it) {
+
+      // If this is a load, save it. If this instruction can read from memory
+      // but is not a load, then we quit. Notice that we don't handle function
+      // calls that read or write.
+      if (it->mayReadFromMemory()) {
+        LoadInst *Ld = dyn_cast<LoadInst>(it);
+        if (!Ld) return false;
+        if (!Ld->isSimple()) {
+          DEBUG(dbgs() << "LV: Found a non-simple load.\n");
+          return false;
+        }
+        Loads.push_back(Ld);
+        continue;
+      }
+
+      // Save 'store' instructions. Abort if other instructions write to memory.
+      if (it->mayWriteToMemory()) {
+        StoreInst *St = dyn_cast<StoreInst>(it);
+        if (!St) return false;
+        if (!St->isSimple()) {
+          DEBUG(dbgs() << "LV: Found a non-simple store.\n");
+          return false;
+        }
+        Stores.push_back(St);
+      }
+    } // next instr.
+  } // next block.
+
+  // Now we have two lists that hold the loads and the stores.
+  // Next, we find the pointers that they use.
+
+  // Check if we see any stores. If there are no stores, then we don't
+  // care if the pointers are *restrict*.
+  if (!Stores.size()) {
+    DEBUG(dbgs() << "LV: Found a read-only loop!\n");
+    return true;
+  }
+
+  // Holds the read and read-write *pointers* that we find.
+  ValueVector Reads;
+  ValueVector ReadWrites;
+
+  // Holds the analyzed pointers. We don't want to call GetUnderlyingObjects
+  // multiple times on the same object. If the ptr is accessed twice, once
+  // for read and once for write, it will only appear once (on the write
+  // list). This is okay, since we are going to check for conflicts between
+  // writes and between reads and writes, but not between reads and reads.
+  ValueSet Seen;
+
+  ValueVector::iterator I, IE;
+  for (I = Stores.begin(), IE = Stores.end(); I != IE; ++I) {
+    StoreInst *ST = cast<StoreInst>(*I);
+    Value* Ptr = ST->getPointerOperand();
+
+    if (isUniform(Ptr)) {
+      DEBUG(dbgs() << "LV: We don't allow storing to uniform addresses\n");
+      return false;
+    }
+
+    // If we did *not* see this pointer before, insert it to
+    // the read-write list. At this phase it is only a 'write' list.
+    if (Seen.insert(Ptr))
+      ReadWrites.push_back(Ptr);
+  }
+
+  for (I = Loads.begin(), IE = Loads.end(); I != IE; ++I) {
+    LoadInst *LD = cast<LoadInst>(*I);
+    Value* Ptr = LD->getPointerOperand();
+    // If we did *not* see this pointer before, insert it to the
+    // read list. If we *did* see it before, then it is already in
+    // the read-write list. This allows us to vectorize expressions
+    // such as A[i] += x;  Because the address of A[i] is a read-write
+    // pointer. This only works if the index of A[i] is consecutive.
+    // If the address of i is unknown (for example A[B[i]]) then we may
+    // read a few words, modify, and write a few words, and some of the
+    // words may be written to the same address.
+    if (Seen.insert(Ptr) || 0 == isConsecutivePtr(Ptr))
+      Reads.push_back(Ptr);
+  }
+
+  // If we write (or read-write) to a single destination and there are no
+  // other reads in this loop then is it safe to vectorize.
+  if (ReadWrites.size() == 1 && Reads.size() == 0) {
+    DEBUG(dbgs() << "LV: Found a write-only loop!\n");
+    return true;
+  }
+
+  // Find pointers with computable bounds. We are going to use this information
+  // to place a runtime bound check.
+  bool CanDoRT = true;
+  for (I = ReadWrites.begin(), IE = ReadWrites.end(); I != IE; ++I)
+    if (hasComputableBounds(*I)) {
+      PtrRtCheck.insert(SE, TheLoop, *I);
+      DEBUG(dbgs() << "LV: Found a runtime check ptr:" << **I <<"\n");
+    } else {
+      CanDoRT = false;
+      break;
+    }
+  for (I = Reads.begin(), IE = Reads.end(); I != IE; ++I)
+    if (hasComputableBounds(*I)) {
+      PtrRtCheck.insert(SE, TheLoop, *I);
+      DEBUG(dbgs() << "LV: Found a runtime check ptr:" << **I <<"\n");
+    } else {
+      CanDoRT = false;
+      break;
+    }
+
+  // Check that we did not collect too many pointers or found a
+  // unsizeable pointer.
+  if (!CanDoRT || PtrRtCheck.Pointers.size() > RuntimeMemoryCheckThreshold) {
+    PtrRtCheck.reset();
+    CanDoRT = false;
+  }
+
+  if (CanDoRT) {
+    DEBUG(dbgs() << "LV: We can perform a memory runtime check if needed.\n");
+  }
+
+  bool NeedRTCheck = false;
+
+  // Now that the pointers are in two lists (Reads and ReadWrites), we
+  // can check that there are no conflicts between each of the writes and
+  // between the writes to the reads.
+  ValueSet WriteObjects;
+  ValueVector TempObjects;
+
+  // Check that the read-writes do not conflict with other read-write
+  // pointers.
+  bool AllWritesIdentified = true;
+  for (I = ReadWrites.begin(), IE = ReadWrites.end(); I != IE; ++I) {
+    GetUnderlyingObjects(*I, TempObjects, DL);
+    for (ValueVector::iterator it=TempObjects.begin(), e=TempObjects.end();
+         it != e; ++it) {
+      if (!isIdentifiedObject(*it)) {
+        DEBUG(dbgs() << "LV: Found an unidentified write ptr:"<< **it <<"\n");
+        NeedRTCheck = true;
+        AllWritesIdentified = false;
+      }
+      if (!WriteObjects.insert(*it)) {
+        DEBUG(dbgs() << "LV: Found a possible write-write reorder:"
+              << **it <<"\n");
+        return false;
+      }
+    }
+    TempObjects.clear();
+  }
+
+  /// Check that the reads don't conflict with the read-writes.
+  for (I = Reads.begin(), IE = Reads.end(); I != IE; ++I) {
+    GetUnderlyingObjects(*I, TempObjects, DL);
+    for (ValueVector::iterator it=TempObjects.begin(), e=TempObjects.end();
+         it != e; ++it) {
+      // If all of the writes are identified then we don't care if the read
+      // pointer is identified or not.
+      if (!AllWritesIdentified && !isIdentifiedObject(*it)) {
+        DEBUG(dbgs() << "LV: Found an unidentified read ptr:"<< **it <<"\n");
+        NeedRTCheck = true;
+      }
+      if (WriteObjects.count(*it)) {
+        DEBUG(dbgs() << "LV: Found a possible read/write reorder:"
+              << **it <<"\n");
+        return false;
+      }
+    }
+    TempObjects.clear();
+  }
+
+  PtrRtCheck.Need = NeedRTCheck;
+  if (NeedRTCheck && !CanDoRT) {
+    DEBUG(dbgs() << "LV: We can't vectorize because we can't find " <<
+          "the array bounds.\n");
+    PtrRtCheck.reset();
+    return false;
+  }
+
+  DEBUG(dbgs() << "LV: We "<< (NeedRTCheck ? "" : "don't") <<
+        " need a runtime memory check.\n");
+  return true;
+}
+
+bool LoopVectorizationLegality::AddReductionVar(PHINode *Phi,
+                                                ReductionKind Kind) {
+  if (Phi->getNumIncomingValues() != 2)
+    return false;
+
+  // Reduction variables are only found in the loop header block.
+  if (Phi->getParent() != TheLoop->getHeader())
+    return false;
+
+  // Obtain the reduction start value from the value that comes from the loop
+  // preheader.
+  Value *RdxStart = Phi->getIncomingValueForBlock(TheLoop->getLoopPreheader());
+
+  // ExitInstruction is the single value which is used outside the loop.
+  // We only allow for a single reduction value to be used outside the loop.
+  // This includes users of the reduction, variables (which form a cycle
+  // which ends in the phi node).
+  Instruction *ExitInstruction = 0;
+  // Indicates that we found a binary operation in our scan.
+  bool FoundBinOp = false;
+
+  // Iter is our iterator. We start with the PHI node and scan for all of the
+  // users of this instruction. All users must be instructions that can be
+  // used as reduction variables (such as ADD). We may have a single
+  // out-of-block user. The cycle must end with the original PHI.
+  Instruction *Iter = Phi;
+  while (true) {
+    // If the instruction has no users then this is a broken
+    // chain and can't be a reduction variable.
+    if (Iter->use_empty())
+      return false;
+
+    // Did we find a user inside this loop already ?
+    bool FoundInBlockUser = false;
+    // Did we reach the initial PHI node already ?
+    bool FoundStartPHI = false;
+
+    // Is this a bin op ?
+    FoundBinOp |= !isa<PHINode>(Iter);
+
+    // For each of the *users* of iter.
+    for (Value::use_iterator it = Iter->use_begin(), e = Iter->use_end();
+         it != e; ++it) {
+      Instruction *U = cast<Instruction>(*it);
+      // We already know that the PHI is a user.
+      if (U == Phi) {
+        FoundStartPHI = true;
+        continue;
+      }
+
+      // Check if we found the exit user.
+      BasicBlock *Parent = U->getParent();
+      if (!TheLoop->contains(Parent)) {
+        // Exit if you find multiple outside users.
+        if (ExitInstruction != 0)
+          return false;
+        ExitInstruction = Iter;
+      }
+
+      // We allow in-loop PHINodes which are not the original reduction PHI
+      // node. If this PHI is the only user of Iter (happens in IF w/ no ELSE
+      // structure) then don't skip this PHI.
+      if (isa<PHINode>(Iter) && isa<PHINode>(U) &&
+          U->getParent() != TheLoop->getHeader() &&
+          TheLoop->contains(U) &&
+          Iter->getNumUses() > 1)
+        continue;
+
+      // We can't have multiple inside users.
+      if (FoundInBlockUser)
+        return false;
+      FoundInBlockUser = true;
+
+      // Any reduction instr must be of one of the allowed kinds.
+      if (!isReductionInstr(U, Kind))
+        return false;
+
+      // Reductions of instructions such as Div, and Sub is only
+      // possible if the LHS is the reduction variable.
+      if (!U->isCommutative() && !isa<PHINode>(U) && U->getOperand(0) != Iter)
+        return false;
+
+      Iter = U;
+    }
+
+    // We found a reduction var if we have reached the original
+    // phi node and we only have a single instruction with out-of-loop
+    // users.
+    if (FoundStartPHI) {
+      // This instruction is allowed to have out-of-loop users.
+      AllowedExit.insert(ExitInstruction);
+
+      // Save the description of this reduction variable.
+      ReductionDescriptor RD(RdxStart, ExitInstruction, Kind);
+      Reductions[Phi] = RD;
+      // We've ended the cycle. This is a reduction variable if we have an
+      // outside user and it has a binary op.
+      return FoundBinOp && ExitInstruction;
+    }
+  }
+}
+
+bool
+LoopVectorizationLegality::isReductionInstr(Instruction *I,
+                                            ReductionKind Kind) {
+  bool FP = I->getType()->isFloatingPointTy();
+  bool FastMath = (FP && I->isCommutative() && I->isAssociative());
+
+  switch (I->getOpcode()) {
+  default:
+    return false;
+  case Instruction::PHI:
+      if (FP && (Kind != RK_FloatMult && Kind != RK_FloatAdd))
+        return false;
+    // possibly.
+    return true;
+  case Instruction::Sub:
+  case Instruction::Add:
+    return Kind == RK_IntegerAdd;
+  case Instruction::SDiv:
+  case Instruction::UDiv:
+  case Instruction::Mul:
+    return Kind == RK_IntegerMult;
+  case Instruction::And:
+    return Kind == RK_IntegerAnd;
+  case Instruction::Or:
+    return Kind == RK_IntegerOr;
+  case Instruction::Xor:
+    return Kind == RK_IntegerXor;
+  case Instruction::FMul:
+    return Kind == RK_FloatMult && FastMath;
+  case Instruction::FAdd:
+    return Kind == RK_FloatAdd && FastMath;
+   }
+}
+
+LoopVectorizationLegality::InductionKind
+LoopVectorizationLegality::isInductionVariable(PHINode *Phi) {
+  Type *PhiTy = Phi->getType();
+  // We only handle integer and pointer inductions variables.
+  if (!PhiTy->isIntegerTy() && !PhiTy->isPointerTy())
+    return IK_NoInduction;
+
+  // Check that the PHI is consecutive and starts at zero.
+  const SCEV *PhiScev = SE->getSCEV(Phi);
+  const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PhiScev);
+  if (!AR) {
+    DEBUG(dbgs() << "LV: PHI is not a poly recurrence.\n");
+    return IK_NoInduction;
+  }
+  const SCEV *Step = AR->getStepRecurrence(*SE);
+
+  // Integer inductions need to have a stride of one.
+  if (PhiTy->isIntegerTy()) {
+    if (Step->isOne())
+      return IK_IntInduction;
+    if (Step->isAllOnesValue())
+      return IK_ReverseIntInduction;
+    return IK_NoInduction;
+  }
+
+  // Calculate the pointer stride and check if it is consecutive.
+  const SCEVConstant *C = dyn_cast<SCEVConstant>(Step);
+  if (!C)
+    return IK_NoInduction;
+
+  assert(PhiTy->isPointerTy() && "The PHI must be a pointer");
+  uint64_t Size = DL->getTypeAllocSize(PhiTy->getPointerElementType());
+  if (C->getValue()->equalsInt(Size))
+    return IK_PtrInduction;
+
+  return IK_NoInduction;
+}
+
+bool LoopVectorizationLegality::isInductionVariable(const Value *V) {
+  Value *In0 = const_cast<Value*>(V);
+  PHINode *PN = dyn_cast_or_null<PHINode>(In0);
+  if (!PN)
+    return false;
+
+  return Inductions.count(PN);
+}
+
+bool LoopVectorizationLegality::blockNeedsPredication(BasicBlock *BB)  {
+  assert(TheLoop->contains(BB) && "Unknown block used");
+
+  // Blocks that do not dominate the latch need predication.
+  BasicBlock* Latch = TheLoop->getLoopLatch();
+  return !DT->dominates(BB, Latch);
+}
+
+bool LoopVectorizationLegality::blockCanBePredicated(BasicBlock *BB) {
+  for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) {
+    // We don't predicate loads/stores at the moment.
+    if (it->mayReadFromMemory() || it->mayWriteToMemory() || it->mayThrow())
+      return false;
+
+    // The instructions below can trap.
+    switch (it->getOpcode()) {
+    default: continue;
+    case Instruction::UDiv:
+    case Instruction::SDiv:
+    case Instruction::URem:
+    case Instruction::SRem:
+             return false;
+    }
+  }
+
+  return true;
+}
+
+bool LoopVectorizationLegality::hasComputableBounds(Value *Ptr) {
+  const SCEV *PhiScev = SE->getSCEV(Ptr);
+  const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PhiScev);
+  if (!AR)
+    return false;
+
+  return AR->isAffine();
+}
+
+unsigned
+LoopVectorizationCostModel::selectVectorizationFactor(bool OptForSize,
+                                                      unsigned UserVF) {
+  if (OptForSize && Legal->getRuntimePointerCheck()->Need) {
+    DEBUG(dbgs() << "LV: Aborting. Runtime ptr check is required in Os.\n");
+    return 1;
+  }
+
+  // Find the trip count.
+  unsigned TC = SE->getSmallConstantTripCount(TheLoop, TheLoop->getLoopLatch());
+  DEBUG(dbgs() << "LV: Found trip count:"<<TC<<"\n");
+
+  unsigned VF = MaxVectorSize;
+
+  // If we optimize the program for size, avoid creating the tail loop.
+  if (OptForSize) {
+    // If we are unable to calculate the trip count then don't try to vectorize.
+    if (TC < 2) {
+      DEBUG(dbgs() << "LV: Aborting. A tail loop is required in Os.\n");
+      return 1;
+    }
+
+    // Find the maximum SIMD width that can fit within the trip count.
+    VF = TC % MaxVectorSize;
+
+    if (VF == 0)
+      VF = MaxVectorSize;
+
+    // If the trip count that we found modulo the vectorization factor is not
+    // zero then we require a tail.
+    if (VF < 2) {
+      DEBUG(dbgs() << "LV: Aborting. A tail loop is required in Os.\n");
+      return 1;
+    }
+  }
+
+  if (UserVF != 0) {
+    assert(isPowerOf2_32(UserVF) && "VF needs to be a power of two");
+    DEBUG(dbgs() << "LV: Using user VF "<<UserVF<<".\n");
+
+    return UserVF;
+  }
+
+  float Cost = expectedCost(1);
+  unsigned Width = 1;
+  DEBUG(dbgs() << "LV: Scalar loop costs: "<< (int)Cost << ".\n");
+  for (unsigned i=2; i <= VF; i*=2) {
+    // Notice that the vector loop needs to be executed less times, so
+    // we need to divide the cost of the vector loops by the width of
+    // the vector elements.
+    float VectorCost = expectedCost(i) / (float)i;
+    DEBUG(dbgs() << "LV: Vector loop of width "<< i << " costs: " <<
+          (int)VectorCost << ".\n");
+    if (VectorCost < Cost) {
+      Cost = VectorCost;
+      Width = i;
+    }
+  }
+
+  DEBUG(dbgs() << "LV: Selecting VF = : "<< Width << ".\n");
+  return Width;
+}
+
+unsigned
+LoopVectorizationCostModel::selectUnrollFactor(bool OptForSize,
+                                               unsigned UserUF) {
+  // Use the user preference, unless 'auto' is selected.
+  if (UserUF != 0)
+    return UserUF;
+
+  // When we optimize for size we don't unroll.
+  if (OptForSize)
+    return 1;
+
+  // Do not unroll loops with a relatively small trip count.
+  unsigned TC = SE->getSmallConstantTripCount(TheLoop,
+                                              TheLoop->getLoopLatch());
+  if (TC > 1 && TC < TinyTripCountUnrollThreshold)
+    return 1;
+
+  unsigned TargetVectorRegisters = TTI.getNumberOfRegisters(true);
+  DEBUG(dbgs() << "LV: The target has " << TargetVectorRegisters <<
+        " vector registers\n");
+
+  LoopVectorizationCostModel::RegisterUsage R = calculateRegisterUsage();
+  // We divide by these constants so assume that we have at least one
+  // instruction that uses at least one register.
+  R.MaxLocalUsers = std::max(R.MaxLocalUsers, 1U);
+  R.NumInstructions = std::max(R.NumInstructions, 1U);
+
+  // We calculate the unroll factor using the following formula.
+  // Subtract the number of loop invariants from the number of available
+  // registers. These registers are used by all of the unrolled instances.
+  // Next, divide the remaining registers by the number of registers that is
+  // required by the loop, in order to estimate how many parallel instances
+  // fit without causing spills.
+  unsigned UF = (TargetVectorRegisters - R.LoopInvariantRegs) / R.MaxLocalUsers;
+
+  // We don't want to unroll the loops to the point where they do not fit into
+  // the decoded cache. Assume that we only allow 32 IR instructions.
+  UF = std::min(UF, (MaxLoopSizeThreshold / R.NumInstructions));
+
+  // Clamp the unroll factor ranges to reasonable factors.
+  if (UF > MaxUnrollSize)
+    UF = MaxUnrollSize;
+  else if (UF < 1)
+    UF = 1;
+
+  return UF;
+}
+
+LoopVectorizationCostModel::RegisterUsage
+LoopVectorizationCostModel::calculateRegisterUsage() {
+  // This function calculates the register usage by measuring the highest number
+  // of values that are alive at a single location. Obviously, this is a very
+  // rough estimation. We scan the loop in a topological order in order and
+  // assign a number to each instruction. We use RPO to ensure that defs are
+  // met before their users. We assume that each instruction that has in-loop
+  // users starts an interval. We record every time that an in-loop value is
+  // used, so we have a list of the first and last occurrences of each
+  // instruction. Next, we transpose this data structure into a multi map that
+  // holds the list of intervals that *end* at a specific location. This multi
+  // map allows us to perform a linear search. We scan the instructions linearly
+  // and record each time that a new interval starts, by placing it in a set.
+  // If we find this value in the multi-map then we remove it from the set.
+  // The max register usage is the maximum size of the set.
+  // We also search for instructions that are defined outside the loop, but are
+  // used inside the loop. We need this number separately from the max-interval
+  // usage number because when we unroll, loop-invariant values do not take
+  // more register.
+  LoopBlocksDFS DFS(TheLoop);
+  DFS.perform(LI);
+
+  RegisterUsage R;
+  R.NumInstructions = 0;
+
+  // Each 'key' in the map opens a new interval. The values
+  // of the map are the index of the 'last seen' usage of the
+  // instruction that is the key.
+  typedef DenseMap<Instruction*, unsigned> IntervalMap;
+  // Maps instruction to its index.
+  DenseMap<unsigned, Instruction*> IdxToInstr;
+  // Marks the end of each interval.
+  IntervalMap EndPoint;
+  // Saves the list of instruction indices that are used in the loop.
+  SmallSet<Instruction*, 8> Ends;
+  // Saves the list of values that are used in the loop but are
+  // defined outside the loop, such as arguments and constants.
+  SmallPtrSet<Value*, 8> LoopInvariants;
+
+  unsigned Index = 0;
+  for (LoopBlocksDFS::RPOIterator bb = DFS.beginRPO(),
+       be = DFS.endRPO(); bb != be; ++bb) {
+    R.NumInstructions += (*bb)->size();
+    for (BasicBlock::iterator it = (*bb)->begin(), e = (*bb)->end(); it != e;
+         ++it) {
+      Instruction *I = it;
+      IdxToInstr[Index++] = I;
+
+      // Save the end location of each USE.
+      for (unsigned i = 0; i < I->getNumOperands(); ++i) {
+        Value *U = I->getOperand(i);
+        Instruction *Instr = dyn_cast<Instruction>(U);
+
+        // Ignore non-instruction values such as arguments, constants, etc.
+        if (!Instr) continue;
+
+        // If this instruction is outside the loop then record it and continue.
+        if (!TheLoop->contains(Instr)) {
+          LoopInvariants.insert(Instr);
+          continue;
+        }
+
+        // Overwrite previous end points.
+        EndPoint[Instr] = Index;
+        Ends.insert(Instr);
+      }
+    }
+  }
+
+  // Saves the list of intervals that end with the index in 'key'.
+  typedef SmallVector<Instruction*, 2> InstrList;
+  DenseMap<unsigned, InstrList> TransposeEnds;
+
+  // Transpose the EndPoints to a list of values that end at each index.
+  for (IntervalMap::iterator it = EndPoint.begin(), e = EndPoint.end();
+       it != e; ++it)
+    TransposeEnds[it->second].push_back(it->first);
+
+  SmallSet<Instruction*, 8> OpenIntervals;
+  unsigned MaxUsage = 0;
+
+
+  DEBUG(dbgs() << "LV(REG): Calculating max register usage:\n");
+  for (unsigned int i = 0; i < Index; ++i) {
+    Instruction *I = IdxToInstr[i];
+    // Ignore instructions that are never used within the loop.
+    if (!Ends.count(I)) continue;
+
+    // Remove all of the instructions that end at this location.
+    InstrList &List = TransposeEnds[i];
+    for (unsigned int j=0, e = List.size(); j < e; ++j)
+      OpenIntervals.erase(List[j]);
+
+    // Count the number of live interals.
+    MaxUsage = std::max(MaxUsage, OpenIntervals.size());
+
+    DEBUG(dbgs() << "LV(REG): At #" << i << " Interval # " <<
+          OpenIntervals.size() <<"\n");
+
+    // Add the current instruction to the list of open intervals.
+    OpenIntervals.insert(I);
+  }
+
+  unsigned Invariant = LoopInvariants.size();
+  DEBUG(dbgs() << "LV(REG): Found max usage: " << MaxUsage << " \n");
+  DEBUG(dbgs() << "LV(REG): Found invariant usage: " << Invariant << " \n");
+  DEBUG(dbgs() << "LV(REG): LoopSize: " << R.NumInstructions << " \n");
+
+  R.LoopInvariantRegs = Invariant;
+  R.MaxLocalUsers = MaxUsage;
+  return R;
+}
+
+unsigned LoopVectorizationCostModel::expectedCost(unsigned VF) {
+  unsigned Cost = 0;
+
+  // For each block.
+  for (Loop::block_iterator bb = TheLoop->block_begin(),
+       be = TheLoop->block_end(); bb != be; ++bb) {
+    unsigned BlockCost = 0;
+    BasicBlock *BB = *bb;
+
+    // For each instruction in the old loop.
+    for (BasicBlock::iterator it = BB->begin(), e = BB->end(); it != e; ++it) {
+      unsigned C = getInstructionCost(it, VF);
+      Cost += C;
+      DEBUG(dbgs() << "LV: Found an estimated cost of "<< C <<" for VF " <<
+            VF << " For instruction: "<< *it << "\n");
+    }
+
+    // We assume that if-converted blocks have a 50% chance of being executed.
+    // When the code is scalar then some of the blocks are avoided due to CF.
+    // When the code is vectorized we execute all code paths.
+    if (Legal->blockNeedsPredication(*bb) && VF == 1)
+      BlockCost /= 2;
+
+    Cost += BlockCost;
+  }
+
+  return Cost;
+}
+
+unsigned
+LoopVectorizationCostModel::getInstructionCost(Instruction *I, unsigned VF) {
+  // If we know that this instruction will remain uniform, check the cost of
+  // the scalar version.
+  if (Legal->isUniformAfterVectorization(I))
+    VF = 1;
+
+  Type *RetTy = I->getType();
+  Type *VectorTy = ToVectorTy(RetTy, VF);
+
+  // TODO: We need to estimate the cost of intrinsic calls.
+  switch (I->getOpcode()) {
+  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 TTI.getCFInstrCost(I->getOpcode());
+  }
+  case Instruction::PHI:
+    //TODO: IF-converted IFs become selects.
+    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 TTI.getArithmeticInstrCost(I->getOpcode(), VectorTy);
+  case Instruction::Select: {
+    SelectInst *SI = cast<SelectInst>(I);
+    const SCEV *CondSCEV = SE->getSCEV(SI->getCondition());
+    bool ScalarCond = (SE->isLoopInvariant(CondSCEV, TheLoop));
+    Type *CondTy = SI->getCondition()->getType();
+    if (ScalarCond)
+      CondTy = VectorType::get(CondTy, VF);
+
+    return TTI.getCmpSelInstrCost(I->getOpcode(), VectorTy, CondTy);
+  }
+  case Instruction::ICmp:
+  case Instruction::FCmp: {
+    Type *ValTy = I->getOperand(0)->getType();
+    VectorTy = ToVectorTy(ValTy, VF);
+    return TTI.getCmpSelInstrCost(I->getOpcode(), VectorTy);
+  }
+  case Instruction::Store: {
+    StoreInst *SI = cast<StoreInst>(I);
+    Type *ValTy = SI->getValueOperand()->getType();
+    VectorTy = ToVectorTy(ValTy, VF);
+
+    if (VF == 1)
+      return TTI.getMemoryOpCost(I->getOpcode(), VectorTy,
+                                   SI->getAlignment(),
+                                   SI->getPointerAddressSpace());
+
+    // Scalarized stores.
+    int Stride = Legal->isConsecutivePtr(SI->getPointerOperand());
+    bool Reverse = Stride < 0;
+    if (0 == Stride) {
+      unsigned Cost = 0;
+
+      // The cost of extracting from the value vector and pointer vector.
+      Type *PtrTy = ToVectorTy(I->getOperand(0)->getType(), VF);
+      for (unsigned i = 0; i < VF; ++i) {
+        Cost += TTI.getVectorInstrCost(Instruction::ExtractElement, VectorTy,
+                                       i);
+        Cost += TTI.getVectorInstrCost(Instruction::ExtractElement, PtrTy, i);
+      }
+
+      // The cost of the scalar stores.
+      Cost += VF * TTI.getMemoryOpCost(I->getOpcode(), ValTy->getScalarType(),
+                                       SI->getAlignment(),
+                                       SI->getPointerAddressSpace());
+      return Cost;
+    }
+
+    // Wide stores.
+    unsigned Cost = TTI.getMemoryOpCost(I->getOpcode(), VectorTy,
+                                        SI->getAlignment(),
+                                        SI->getPointerAddressSpace());
+    if (Reverse)
+      Cost += TTI.getShuffleCost(TargetTransformInfo::SK_Reverse,
+                                  VectorTy, 0);
+    return Cost;
+  }
+  case Instruction::Load: {
+    LoadInst *LI = cast<LoadInst>(I);
+
+    if (VF == 1)
+      return TTI.getMemoryOpCost(I->getOpcode(), VectorTy, LI->getAlignment(),
+                                 LI->getPointerAddressSpace());
+
+    // Scalarized loads.
+    int Stride = Legal->isConsecutivePtr(LI->getPointerOperand());
+    bool Reverse = Stride < 0;
+    if (0 == Stride) {
+      unsigned Cost = 0;
+      Type *PtrTy = ToVectorTy(I->getOperand(0)->getType(), VF);
+
+      // The cost of extracting from the pointer vector.
+      for (unsigned i = 0; i < VF; ++i)
+        Cost += TTI.getVectorInstrCost(Instruction::ExtractElement, PtrTy, i);
+
+      // The cost of inserting data to the result vector.
+      for (unsigned i = 0; i < VF; ++i)
+        Cost += TTI.getVectorInstrCost(Instruction::InsertElement, VectorTy, i);
+
+      // The cost of the scalar stores.
+      Cost += VF * TTI.getMemoryOpCost(I->getOpcode(), RetTy->getScalarType(),
+                                       LI->getAlignment(),
+                                       LI->getPointerAddressSpace());
+      return Cost;
+    }
+
+    // Wide loads.
+    unsigned Cost = TTI.getMemoryOpCost(I->getOpcode(), VectorTy,
+                                        LI->getAlignment(),
+                                        LI->getPointerAddressSpace());
+    if (Reverse)
+      Cost += TTI.getShuffleCost(TargetTransformInfo::SK_Reverse, VectorTy, 0);
+    return Cost;
+  }
+  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: {
+    // We optimize the truncation of induction variable.
+    // The cost of these is the same as the scalar operation.
+    if (I->getOpcode() == Instruction::Trunc &&
+        Legal->isInductionVariable(I->getOperand(0)))
+      return TTI.getCastInstrCost(I->getOpcode(), I->getType(),
+                                  I->getOperand(0)->getType());
+
+    Type *SrcVecTy = ToVectorTy(I->getOperand(0)->getType(), VF);
+    return TTI.getCastInstrCost(I->getOpcode(), VectorTy, SrcVecTy);
+  }
+  case Instruction::Call: {
+    assert(isTriviallyVectorizableIntrinsic(I));
+    IntrinsicInst *II = cast<IntrinsicInst>(I);
+    Type *RetTy = ToVectorTy(II->getType(), VF);
+    SmallVector<Type*, 4> Tys;
+    for (unsigned i = 0, ie = II->getNumArgOperands(); i != ie; ++i)
+      Tys.push_back(ToVectorTy(II->getArgOperand(i)->getType(), VF));
+    return TTI.getIntrinsicInstrCost(II->getIntrinsicID(), RetTy, Tys);
+  }
+  default: {
+    // We are scalarizing the instruction. Return the cost of the scalar
+    // instruction, plus the cost of insert and extract into vector
+    // elements, times the vector width.
+    unsigned Cost = 0;
+
+    if (!RetTy->isVoidTy() && VF != 1) {
+      unsigned InsCost = TTI.getVectorInstrCost(Instruction::InsertElement,
+                                                VectorTy);
+      unsigned ExtCost = TTI.getVectorInstrCost(Instruction::ExtractElement,
+                                                VectorTy);
+
+      // The cost of inserting the results plus extracting each one of the
+      // operands.
+      Cost += VF * (InsCost + ExtCost * I->getNumOperands());
+    }
+
+    // The cost of executing VF copies of the scalar instruction. This opcode
+    // is unknown. Assume that it is the same as 'mul'.
+    Cost += VF * TTI.getArithmeticInstrCost(Instruction::Mul, VectorTy);
+    return Cost;
+  }
+  }// end of switch.
+}
+
+Type* LoopVectorizationCostModel::ToVectorTy(Type *Scalar, unsigned VF) {
+  if (Scalar->isVoidTy() || VF == 1)
+    return Scalar;
+  return VectorType::get(Scalar, VF);
+}
+
+char LoopVectorize::ID = 0;
+static const char lv_name[] = "Loop Vectorization";
+INITIALIZE_PASS_BEGIN(LoopVectorize, LV_NAME, lv_name, false, false)
+INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
+INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
+INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
+INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false)
+
+namespace llvm {
+  Pass *createLoopVectorizePass() {
+    return new LoopVectorize();
+  }
+}
+
+
diff --git a/lib/Transforms/Vectorize/Vectorize.cpp b/lib/Transforms/Vectorize/Vectorize.cpp
index 1ef6002..19eefd2 100644
--- a/lib/Transforms/Vectorize/Vectorize.cpp
+++ b/lib/Transforms/Vectorize/Vectorize.cpp
@@ -1,4 +1,4 @@
-//===-- Vectorize.cpp -----------------------------------------------------===//
+   //===-- Vectorize.cpp -----------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -7,26 +7,27 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file implements common infrastructure for libLLVMVectorizeOpts.a, which 
+// This file implements common infrastructure for libLLVMVectorizeOpts.a, which
 // implements several vectorization transformations over the LLVM intermediate
 // representation, including the C bindings for that library.
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm-c/Transforms/Vectorize.h"
+#include "llvm/Transforms/Vectorize.h"
 #include "llvm-c/Initialization.h"
-#include "llvm/InitializePasses.h"
-#include "llvm/PassManager.h"
+#include "llvm-c/Transforms/Vectorize.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Analysis/Verifier.h"
-#include "llvm/Transforms/Vectorize.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/PassManager.h"
 
 using namespace llvm;
 
-/// initializeVectorizationPasses - Initialize all passes linked into the 
+/// initializeVectorizationPasses - Initialize all passes linked into the
 /// Vectorization library.
 void llvm::initializeVectorization(PassRegistry &Registry) {
   initializeBBVectorizePass(Registry);
+  initializeLoopVectorizePass(Registry);
 }
 
 void LLVMInitializeVectorization(LLVMPassRegistryRef R) {
@@ -37,3 +38,6 @@ void LLVMAddBBVectorizePass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createBBVectorizePass());
 }
 
+void LLVMAddLoopVectorizePass(LLVMPassManagerRef PM) {
+  unwrap(PM)->add(createLoopVectorizePass());
+}