Merge commit 'b3201c5cf1e183d840f7c99ff779d57f1549d8e5' into merge_20130226

Conflicts:
	include/llvm/Support/ELF.h
	lib/Support/DeltaAlgorithm.cpp

Change-Id: I24a4fbce62eb39d924efee3c687b55e1e17b30cd

18 files changed, 213 insertions, 4551 deletions

diff --git a/lib/Transforms/Scalar/CMakeLists.txt b/lib/Transforms/Scalar/CMakeLists.txt
index b3fc6e3..fd55e08 100644
--- a/lib/Transforms/Scalar/CMakeLists.txt
+++ b/lib/Transforms/Scalar/CMakeLists.txt
@@ -21,7 +21,6 @@ add_llvm_library(LLVMScalarOpts
   LoopUnswitch.cpp
   LowerAtomic.cpp
   MemCpyOptimizer.cpp
-  ObjCARC.cpp
   Reassociate.cpp
   Reg2Mem.cpp
   SCCP.cpp
diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index d513c96..d71dd5d 100644
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -729,9 +729,9 @@ bool CodeGenPrepare::DupRetToEnableTailCallOpts(BasicBlock *BB) {
   // It's not safe to eliminate the sign / zero extension of the return value.
   // See llvm::isInTailCallPosition().
   const Function *F = BB->getParent();
-  Attribute CallerRetAttr = F->getAttributes().getRetAttributes();
-  if (CallerRetAttr.hasAttribute(Attribute::ZExt) ||
-      CallerRetAttr.hasAttribute(Attribute::SExt))
+  AttributeSet CallerAttrs = F->getAttributes();
+  if (CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::ZExt) ||
+      CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::SExt))
     return false;
 
   // Make sure there are no instructions between the PHI and return, or that the
@@ -788,10 +788,10 @@ bool CodeGenPrepare::DupRetToEnableTailCallOpts(BasicBlock *BB) {
 
     // Conservatively require the attributes of the call to match those of the
     // return. Ignore noalias because it doesn't affect the call sequence.
-    Attribute CalleeRetAttr = CS.getAttributes().getRetAttributes();
-    if (AttrBuilder(CalleeRetAttr).
+    AttributeSet CalleeAttrs = CS.getAttributes();
+    if (AttrBuilder(CalleeAttrs, AttributeSet::ReturnIndex).
           removeAttribute(Attribute::NoAlias) !=
-        AttrBuilder(CallerRetAttr).
+        AttrBuilder(CalleeAttrs, AttributeSet::ReturnIndex).
           removeAttribute(Attribute::NoAlias))
       continue;
 
diff --git a/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
index 4c3631b..995782e 100644
--- a/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
+++ b/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -21,6 +21,8 @@
 #include "llvm/IR/Instructions.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/CFG.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Utils/Local.h"
 using namespace llvm;
 
@@ -97,12 +99,29 @@ bool CorrelatedValuePropagation::processPHI(PHINode *P) {
     Value *Incoming = P->getIncomingValue(i);
     if (isa<Constant>(Incoming)) continue;
 
-    Constant *C = LVI->getConstantOnEdge(P->getIncomingValue(i),
-                                         P->getIncomingBlock(i),
-                                         BB);
-    if (!C) continue;
+    Value *V = LVI->getConstantOnEdge(Incoming, P->getIncomingBlock(i), BB);
 
-    P->setIncomingValue(i, C);
+    // Look if the incoming value is a select with a constant but LVI tells us
+    // that the incoming value can never be that constant. In that case replace
+    // the incoming value with the other value of the select. This often allows
+    // us to remove the select later.
+    if (!V) {
+      SelectInst *SI = dyn_cast<SelectInst>(Incoming);
+      if (!SI) continue;
+
+      Constant *C = dyn_cast<Constant>(SI->getFalseValue());
+      if (!C) continue;
+
+      if (LVI->getPredicateOnEdge(ICmpInst::ICMP_EQ, SI, C,
+                                  P->getIncomingBlock(i), BB) !=
+          LazyValueInfo::False)
+        continue;
+
+      DEBUG(dbgs() << "CVP: Threading PHI over " << *SI << '\n');
+      V = SI->getTrueValue();
+    }
+
+    P->setIncomingValue(i, V);
     Changed = true;
   }
 
diff --git a/lib/Transforms/Scalar/DeadStoreElimination.cpp b/lib/Transforms/Scalar/DeadStoreElimination.cpp
index fe3acbf..57432c7 100644
--- a/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -376,10 +376,10 @@ static OverwriteResult isOverwrite(const AliasAnalysis::Location &Later,
   // Check to see if the later store is to the entire object (either a global,
   // an alloca, or a byval argument).  If so, then it clearly overwrites any
   // other store to the same object.
-  const DataLayout &TD = *AA.getDataLayout();
+  const DataLayout *TD = AA.getDataLayout();
 
-  const Value *UO1 = GetUnderlyingObject(P1, &TD),
-              *UO2 = GetUnderlyingObject(P2, &TD);
+  const Value *UO1 = GetUnderlyingObject(P1, TD),
+              *UO2 = GetUnderlyingObject(P2, TD);
 
   // If we can't resolve the same pointers to the same object, then we can't
   // analyze them at all.
diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 14201b9..c04b447 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -849,8 +849,8 @@ static int AnalyzeLoadFromClobberingWrite(Type *LoadTy, Value *LoadPtr,
     return -1;
 
   int64_t StoreOffset = 0, LoadOffset = 0;
-  Value *StoreBase = GetPointerBaseWithConstantOffset(WritePtr, StoreOffset,TD);
-  Value *LoadBase = GetPointerBaseWithConstantOffset(LoadPtr, LoadOffset, TD);
+  Value *StoreBase = GetPointerBaseWithConstantOffset(WritePtr,StoreOffset,&TD);
+  Value *LoadBase = GetPointerBaseWithConstantOffset(LoadPtr, LoadOffset, &TD);
   if (StoreBase != LoadBase)
     return -1;
 
@@ -945,7 +945,7 @@ static int AnalyzeLoadFromClobberingLoad(Type *LoadTy, Value *LoadPtr,
   // then we should widen it!
   int64_t LoadOffs = 0;
   const Value *LoadBase =
-    GetPointerBaseWithConstantOffset(LoadPtr, LoadOffs, TD);
+    GetPointerBaseWithConstantOffset(LoadPtr, LoadOffs, &TD);
   unsigned LoadSize = TD.getTypeStoreSize(LoadTy);
 
   unsigned Size = MemoryDependenceAnalysis::
@@ -1526,10 +1526,8 @@ bool GVN::processNonLocalLoad(LoadInst *LI) {
   BasicBlock *LoadBB = LI->getParent();
   BasicBlock *TmpBB = LoadBB;
 
-  bool isSinglePred = false;
   bool allSingleSucc = true;
   while (TmpBB->getSinglePredecessor()) {
-    isSinglePred = true;
     TmpBB = TmpBB->getSinglePredecessor();
     if (TmpBB == LoadBB) // Infinite (unreachable) loop.
       return false;
@@ -1548,28 +1546,6 @@ bool GVN::processNonLocalLoad(LoadInst *LI) {
   assert(TmpBB);
   LoadBB = TmpBB;
 
-  // FIXME: It is extremely unclear what this loop is doing, other than
-  // artificially restricting loadpre.
-  if (isSinglePred) {
-    bool isHot = false;
-    for (unsigned i = 0, e = ValuesPerBlock.size(); i != e; ++i) {
-      const AvailableValueInBlock &AV = ValuesPerBlock[i];
-      if (AV.isSimpleValue())
-        // "Hot" Instruction is in some loop (because it dominates its dep.
-        // instruction).
-        if (Instruction *I = dyn_cast<Instruction>(AV.getSimpleValue()))
-          if (DT->dominates(LI, I)) {
-            isHot = true;
-            break;
-          }
-    }
-
-    // We are interested only in "hot" instructions. We don't want to do any
-    // mis-optimizations here.
-    if (!isHot)
-      return false;
-  }
-
   // Check to see how many predecessors have the loaded value fully
   // available.
   DenseMap<BasicBlock*, Value*> PredLoads;
@@ -2371,8 +2347,8 @@ bool GVN::processBlock(BasicBlock *BB) {
          E = InstrsToErase.end(); I != E; ++I) {
       DEBUG(dbgs() << "GVN removed: " << **I << '\n');
       if (MD) MD->removeInstruction(*I);
-      (*I)->eraseFromParent();
       DEBUG(verifyRemoved(*I));
+      (*I)->eraseFromParent();
     }
     InstrsToErase.clear();
 
@@ -2389,7 +2365,7 @@ bool GVN::processBlock(BasicBlock *BB) {
 /// control flow patterns and attempts to perform simple PRE at the join point.
 bool GVN::performPRE(Function &F) {
   bool Changed = false;
-  DenseMap<BasicBlock*, Value*> predMap;
+  SmallVector<std::pair<Value*, BasicBlock*>, 8> predMap;
   for (df_iterator<BasicBlock*> DI = df_begin(&F.getEntryBlock()),
        DE = df_end(&F.getEntryBlock()); DI != DE; ++DI) {
     BasicBlock *CurrentBlock = *DI;
@@ -2445,19 +2421,22 @@ bool GVN::performPRE(Function &F) {
         if (P == CurrentBlock) {
           NumWithout = 2;
           break;
-        } else if (!DT->dominates(&F.getEntryBlock(), P))  {
+        } else if (!DT->isReachableFromEntry(P))  {
           NumWithout = 2;
           break;
         }
 
         Value* predV = findLeader(P, ValNo);
         if (predV == 0) {
+          predMap.push_back(std::make_pair(static_cast<Value *>(0), P));
           PREPred = P;
           ++NumWithout;
         } else if (predV == CurInst) {
+          /* CurInst dominates this predecessor. */
           NumWithout = 2;
+          break;
         } else {
-          predMap[P] = predV;
+          predMap.push_back(std::make_pair(predV, P));
           ++NumWith;
         }
       }
@@ -2504,15 +2483,14 @@ bool GVN::performPRE(Function &F) {
       // the PRE predecessor.  This is typically because of loads which
       // are not value numbered precisely.
       if (!success) {
-        delete PREInstr;
         DEBUG(verifyRemoved(PREInstr));
+        delete PREInstr;
         continue;
       }
 
       PREInstr->insertBefore(PREPred->getTerminator());
       PREInstr->setName(CurInst->getName() + ".pre");
       PREInstr->setDebugLoc(CurInst->getDebugLoc());
-      predMap[PREPred] = PREInstr;
       VN.add(PREInstr, ValNo);
       ++NumGVNPRE;
 
@@ -2520,13 +2498,14 @@ bool GVN::performPRE(Function &F) {
       addToLeaderTable(ValNo, PREInstr, PREPred);
 
       // Create a PHI to make the value available in this block.
-      pred_iterator PB = pred_begin(CurrentBlock), PE = pred_end(CurrentBlock);
-      PHINode* Phi = PHINode::Create(CurInst->getType(), std::distance(PB, PE),
+      PHINode* Phi = PHINode::Create(CurInst->getType(), predMap.size(),
                                      CurInst->getName() + ".pre-phi",
                                      CurrentBlock->begin());
-      for (pred_iterator PI = PB; PI != PE; ++PI) {
-        BasicBlock *P = *PI;
-        Phi->addIncoming(predMap[P], P);
+      for (unsigned i = 0, e = predMap.size(); i != e; ++i) {
+        if (Value *V = predMap[i].first)
+          Phi->addIncoming(V, predMap[i].second);
+        else
+          Phi->addIncoming(PREInstr, PREPred);
       }
 
       VN.add(Phi, ValNo);
@@ -2551,8 +2530,8 @@ bool GVN::performPRE(Function &F) {
 
       DEBUG(dbgs() << "GVN PRE removed: " << *CurInst << '\n');
       if (MD) MD->removeInstruction(CurInst);
-      CurInst->eraseFromParent();
       DEBUG(verifyRemoved(CurInst));
+      CurInst->eraseFromParent();
       Changed = true;
     }
   }
diff --git a/lib/Transforms/Scalar/LICM.cpp b/lib/Transforms/Scalar/LICM.cpp
index dc6bef7..f94cd2a 100644
--- a/lib/Transforms/Scalar/LICM.cpp
+++ b/lib/Transforms/Scalar/LICM.cpp
@@ -440,13 +440,12 @@ bool LICM::canSinkOrHoistInst(Instruction &I) {
   }
 
   // Only these instructions are hoistable/sinkable.
-  bool HoistableKind = (isa<BinaryOperator>(I) || isa<CastInst>(I) ||
-                            isa<SelectInst>(I) || isa<GetElementPtrInst>(I) ||
-                            isa<CmpInst>(I)    || isa<InsertElementInst>(I) ||
-                            isa<ExtractElementInst>(I) ||
-                            isa<ShuffleVectorInst>(I));
-  if (!HoistableKind)
-      return false;
+  if (!isa<BinaryOperator>(I) && !isa<CastInst>(I) && !isa<SelectInst>(I) &&
+      !isa<GetElementPtrInst>(I) && !isa<CmpInst>(I) &&
+      !isa<InsertElementInst>(I) && !isa<ExtractElementInst>(I) &&
+      !isa<ShuffleVectorInst>(I) && !isa<ExtractValueInst>(I) &&
+      !isa<InsertValueInst>(I))
+    return false;
 
   return isSafeToExecuteUnconditionally(I);
 }
diff --git a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index c4f9012..8258719 100644
--- a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -407,7 +407,7 @@ bool NclPopcountRecognize::detectIdiom(Instruction *&CntInst,
 
   // step 2: detect instructions corresponding to "x2 = x1 & (x1 - 1)"
   {
-    if (DefX2->getOpcode() != Instruction::And)
+    if (!DefX2 || DefX2->getOpcode() != Instruction::And)
       return false;
 
     BinaryOperator *SubOneOp;
diff --git a/lib/Transforms/Scalar/LoopInstSimplify.cpp b/lib/Transforms/Scalar/LoopInstSimplify.cpp
index c48808f..a23860a 100644
--- a/lib/Transforms/Scalar/LoopInstSimplify.cpp
+++ b/lib/Transforms/Scalar/LoopInstSimplify.cpp
@@ -14,6 +14,7 @@
 #define DEBUG_TYPE "loop-instsimplify"
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopInfo.h"
diff --git a/lib/Transforms/Scalar/LoopRotation.cpp b/lib/Transforms/Scalar/LoopRotation.cpp
index 0ea80f3..e98ae95 100644
--- a/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/lib/Transforms/Scalar/LoopRotation.cpp
@@ -18,6 +18,7 @@
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopPass.h"
 #include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IntrinsicInst.h"
@@ -51,6 +52,7 @@ namespace {
       AU.addRequiredID(LCSSAID);
       AU.addPreservedID(LCSSAID);
       AU.addPreserved<ScalarEvolution>();
+      AU.addRequired<TargetTransformInfo>();
     }
 
     bool runOnLoop(Loop *L, LPPassManager &LPM);
@@ -59,11 +61,13 @@ namespace {
 
   private:
     LoopInfo *LI;
+    const TargetTransformInfo *TTI;
   };
 }
 
 char LoopRotate::ID = 0;
 INITIALIZE_PASS_BEGIN(LoopRotate, "loop-rotate", "Rotate Loops", false, false)
+INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
 INITIALIZE_PASS_DEPENDENCY(LoopInfo)
 INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
 INITIALIZE_PASS_DEPENDENCY(LCSSA)
@@ -75,6 +79,7 @@ Pass *llvm::createLoopRotatePass() { return new LoopRotate(); }
 /// the loop is rotated at least once.
 bool LoopRotate::runOnLoop(Loop *L, LPPassManager &LPM) {
   LI = &getAnalysis<LoopInfo>();
+  TTI = &getAnalysis<TargetTransformInfo>();
 
   // Simplify the loop latch before attempting to rotate the header
   // upward. Rotation may not be needed if the loop tail can be folded into the
@@ -278,7 +283,7 @@ bool LoopRotate::rotateLoop(Loop *L) {
   // duplicate blocks inside it.
   {
     CodeMetrics Metrics;
-    Metrics.analyzeBasicBlock(OrigHeader);
+    Metrics.analyzeBasicBlock(OrigHeader, *TTI);
     if (Metrics.notDuplicatable) {
       DEBUG(dbgs() << "LoopRotation: NOT rotating - contains non duplicatable"
             << " instructions: "; L->dump());
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index c7b853e..4e4cb86 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -58,6 +58,7 @@
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallBitVector.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/IVUsers.h"
 #include "llvm/Analysis/LoopPass.h"
@@ -237,7 +238,7 @@ struct Formula {
 
   /// BaseRegs - The list of "base" registers for this use. When this is
   /// non-empty,
-  SmallVector<const SCEV *, 2> BaseRegs;
+  SmallVector<const SCEV *, 4> BaseRegs;
 
   /// ScaledReg - The 'scaled' register for this use. This should be non-null
   /// when Scale is not zero.
@@ -1087,19 +1088,19 @@ namespace {
 /// UniquifierDenseMapInfo - A DenseMapInfo implementation for holding
 /// DenseMaps and DenseSets of sorted SmallVectors of const SCEV*.
 struct UniquifierDenseMapInfo {
-  static SmallVector<const SCEV *, 2> getEmptyKey() {
-    SmallVector<const SCEV *, 2> V;
+  static SmallVector<const SCEV *, 4> getEmptyKey() {
+    SmallVector<const SCEV *, 4>  V;
     V.push_back(reinterpret_cast<const SCEV *>(-1));
     return V;
   }
 
-  static SmallVector<const SCEV *, 2> getTombstoneKey() {
-    SmallVector<const SCEV *, 2> V;
+  static SmallVector<const SCEV *, 4> getTombstoneKey() {
+    SmallVector<const SCEV *, 4> V;
     V.push_back(reinterpret_cast<const SCEV *>(-2));
     return V;
   }
 
-  static unsigned getHashValue(const SmallVector<const SCEV *, 2> &V) {
+  static unsigned getHashValue(const SmallVector<const SCEV *, 4> &V) {
     unsigned Result = 0;
     for (SmallVectorImpl<const SCEV *>::const_iterator I = V.begin(),
          E = V.end(); I != E; ++I)
@@ -1107,8 +1108,8 @@ struct UniquifierDenseMapInfo {
     return Result;
   }
 
-  static bool isEqual(const SmallVector<const SCEV *, 2> &LHS,
-                      const SmallVector<const SCEV *, 2> &RHS) {
+  static bool isEqual(const SmallVector<const SCEV *, 4> &LHS,
+                      const SmallVector<const SCEV *, 4> &RHS) {
     return LHS == RHS;
   }
 };
@@ -1119,7 +1120,7 @@ struct UniquifierDenseMapInfo {
 /// the user itself, and information about how the use may be satisfied.
 /// TODO: Represent multiple users of the same expression in common?
 class LSRUse {
-  DenseSet<SmallVector<const SCEV *, 2>, UniquifierDenseMapInfo> Uniquifier;
+  DenseSet<SmallVector<const SCEV *, 4>, UniquifierDenseMapInfo> Uniquifier;
 
 public:
   /// KindType - An enum for a kind of use, indicating what types of
@@ -1178,7 +1179,7 @@ public:
 /// HasFormula - Test whether this use as a formula which has the same
 /// registers as the given formula.
 bool LSRUse::HasFormulaWithSameRegs(const Formula &F) const {
-  SmallVector<const SCEV *, 2> Key = F.BaseRegs;
+  SmallVector<const SCEV *, 4> Key = F.BaseRegs;
   if (F.ScaledReg) Key.push_back(F.ScaledReg);
   // Unstable sort by host order ok, because this is only used for uniquifying.
   std::sort(Key.begin(), Key.end());
@@ -1188,7 +1189,7 @@ bool LSRUse::HasFormulaWithSameRegs(const Formula &F) const {
 /// InsertFormula - If the given formula has not yet been inserted, add it to
 /// the list, and return true. Return false otherwise.
 bool LSRUse::InsertFormula(const Formula &F) {
-  SmallVector<const SCEV *, 2> Key = F.BaseRegs;
+  SmallVector<const SCEV *, 4> Key = F.BaseRegs;
   if (F.ScaledReg) Key.push_back(F.ScaledReg);
   // Unstable sort by host order ok, because this is only used for uniquifying.
   std::sort(Key.begin(), Key.end());
@@ -2536,6 +2537,7 @@ void LSRInstance::ChainInstruction(Instruction *UserInst, Instruction *IVOper,
     // Add this IV user to the end of the chain.
     IVChainVec[ChainIdx].add(IVInc(UserInst, IVOper, LastIncExpr));
   }
+  IVChain &Chain = IVChainVec[ChainIdx];
 
   SmallPtrSet<Instruction*,4> &NearUsers = ChainUsersVec[ChainIdx].NearUsers;
   // This chain's NearUsers become FarUsers.
@@ -2553,8 +2555,19 @@ void LSRInstance::ChainInstruction(Instruction *UserInst, Instruction *IVOper,
   for (Value::use_iterator UseIter = IVOper->use_begin(),
          UseEnd = IVOper->use_end(); UseIter != UseEnd; ++UseIter) {
     Instruction *OtherUse = dyn_cast<Instruction>(*UseIter);
-    if (!OtherUse || OtherUse == UserInst)
+    if (!OtherUse)
       continue;
+    // Uses in the chain will no longer be uses if the chain is formed.
+    // Include the head of the chain in this iteration (not Chain.begin()).
+    IVChain::const_iterator IncIter = Chain.Incs.begin();
+    IVChain::const_iterator IncEnd = Chain.Incs.end();
+    for( ; IncIter != IncEnd; ++IncIter) {
+      if (IncIter->UserInst == OtherUse)
+        break;
+    }
+    if (IncIter != IncEnd)
+      continue;
+
     if (SE.isSCEVable(OtherUse->getType())
         && !isa<SCEVUnknown>(SE.getSCEV(OtherUse))
         && IU.isIVUserOrOperand(OtherUse)) {
@@ -2891,7 +2904,6 @@ void
 LSRInstance::InsertInitialFormula(const SCEV *S, LSRUse &LU, size_t LUIdx) {
   Formula F;
   F.InitialMatch(S, L, SE);
-  F.HasBaseReg = true;
   bool Inserted = InsertFormula(LU, LUIdx, F);
   assert(Inserted && "Initial formula already exists!"); (void)Inserted;
 }
@@ -2903,6 +2915,7 @@ LSRInstance::InsertSupplementalFormula(const SCEV *S,
                                        LSRUse &LU, size_t LUIdx) {
   Formula F;
   F.BaseRegs.push_back(S);
+  F.HasBaseReg = true;
   bool Inserted = InsertFormula(LU, LUIdx, F);
   assert(Inserted && "Supplemental formula already exists!"); (void)Inserted;
 }
@@ -3656,7 +3669,7 @@ void LSRInstance::FilterOutUndesirableDedicatedRegisters() {
 
   // Collect the best formula for each unique set of shared registers. This
   // is reset for each use.
-  typedef DenseMap<SmallVector<const SCEV *, 2>, size_t, UniquifierDenseMapInfo>
+  typedef DenseMap<SmallVector<const SCEV *, 4>, size_t, UniquifierDenseMapInfo>
     BestFormulaeTy;
   BestFormulaeTy BestFormulae;
 
@@ -3691,7 +3704,7 @@ void LSRInstance::FilterOutUndesirableDedicatedRegisters() {
               dbgs() << "\n");
       }
       else {
-        SmallVector<const SCEV *, 2> Key;
+        SmallVector<const SCEV *, 4> Key;
         for (SmallVectorImpl<const SCEV *>::const_iterator J = F.BaseRegs.begin(),
                JE = F.BaseRegs.end(); J != JE; ++J) {
           const SCEV *Reg = *J;
@@ -3837,83 +3850,83 @@ void LSRInstance::NarrowSearchSpaceByDetectingSupersets() {
 /// for expressions like A, A+1, A+2, etc., allocate a single register for
 /// them.
 void LSRInstance::NarrowSearchSpaceByCollapsingUnrolledCode() {
-  if (EstimateSearchSpaceComplexity() >= ComplexityLimit) {
-    DEBUG(dbgs() << "The search space is too complex.\n");
+  if (EstimateSearchSpaceComplexity() < ComplexityLimit)
+    return;
 
-    DEBUG(dbgs() << "Narrowing the search space by assuming that uses "
-                    "separated by a constant offset will use the same "
-                    "registers.\n");
+  DEBUG(dbgs() << "The search space is too complex.\n"
+                  "Narrowing the search space by assuming that uses separated "
+                  "by a constant offset will use the same registers.\n");
 
-    // This is especially useful for unrolled loops.
+  // This is especially useful for unrolled loops.
 
-    for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) {
-      LSRUse &LU = Uses[LUIdx];
-      for (SmallVectorImpl<Formula>::const_iterator I = LU.Formulae.begin(),
-           E = LU.Formulae.end(); I != E; ++I) {
-        const Formula &F = *I;
-        if (F.BaseOffset != 0 && F.Scale == 0) {
-          if (LSRUse *LUThatHas = FindUseWithSimilarFormula(F, LU)) {
-            if (reconcileNewOffset(*LUThatHas, F.BaseOffset,
-                                   /*HasBaseReg=*/false,
-                                   LU.Kind, LU.AccessTy)) {
-              DEBUG(dbgs() << "  Deleting use "; LU.print(dbgs());
-                    dbgs() << '\n');
-
-              LUThatHas->AllFixupsOutsideLoop &= LU.AllFixupsOutsideLoop;
-
-              // Update the relocs to reference the new use.
-              for (SmallVectorImpl<LSRFixup>::iterator I = Fixups.begin(),
-                   E = Fixups.end(); I != E; ++I) {
-                LSRFixup &Fixup = *I;
-                if (Fixup.LUIdx == LUIdx) {
-                  Fixup.LUIdx = LUThatHas - &Uses.front();
-                  Fixup.Offset += F.BaseOffset;
-                  // Add the new offset to LUThatHas' offset list.
-                  if (LUThatHas->Offsets.back() != Fixup.Offset) {
-                    LUThatHas->Offsets.push_back(Fixup.Offset);
-                    if (Fixup.Offset > LUThatHas->MaxOffset)
-                      LUThatHas->MaxOffset = Fixup.Offset;
-                    if (Fixup.Offset < LUThatHas->MinOffset)
-                      LUThatHas->MinOffset = Fixup.Offset;
-                  }
-                  DEBUG(dbgs() << "New fixup has offset "
-                               << Fixup.Offset << '\n');
-                }
-                if (Fixup.LUIdx == NumUses-1)
-                  Fixup.LUIdx = LUIdx;
-              }
+  for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) {
+    LSRUse &LU = Uses[LUIdx];
+    for (SmallVectorImpl<Formula>::const_iterator I = LU.Formulae.begin(),
+         E = LU.Formulae.end(); I != E; ++I) {
+      const Formula &F = *I;
+      if (F.BaseOffset == 0 || F.Scale != 0)
+        continue;
 
-              // Delete formulae from the new use which are no longer legal.
-              bool Any = false;
-              for (size_t i = 0, e = LUThatHas->Formulae.size(); i != e; ++i) {
-                Formula &F = LUThatHas->Formulae[i];
-                if (!isLegalUse(TTI, LUThatHas->MinOffset, LUThatHas->MaxOffset,
-                                LUThatHas->Kind, LUThatHas->AccessTy, F)) {
-                  DEBUG(dbgs() << "  Deleting "; F.print(dbgs());
-                        dbgs() << '\n');
-                  LUThatHas->DeleteFormula(F);
-                  --i;
-                  --e;
-                  Any = true;
-                }
-              }
-              if (Any)
-                LUThatHas->RecomputeRegs(LUThatHas - &Uses.front(), RegUses);
+      LSRUse *LUThatHas = FindUseWithSimilarFormula(F, LU);
+      if (!LUThatHas)
+        continue;
 
-              // Delete the old use.
-              DeleteUse(LU, LUIdx);
-              --LUIdx;
-              --NumUses;
-              break;
-            }
+      if (!reconcileNewOffset(*LUThatHas, F.BaseOffset, /*HasBaseReg=*/ false,
+                              LU.Kind, LU.AccessTy))
+        continue;
+
+      DEBUG(dbgs() << "  Deleting use "; LU.print(dbgs()); dbgs() << '\n');
+
+      LUThatHas->AllFixupsOutsideLoop &= LU.AllFixupsOutsideLoop;
+
+      // Update the relocs to reference the new use.
+      for (SmallVectorImpl<LSRFixup>::iterator I = Fixups.begin(),
+           E = Fixups.end(); I != E; ++I) {
+        LSRFixup &Fixup = *I;
+        if (Fixup.LUIdx == LUIdx) {
+          Fixup.LUIdx = LUThatHas - &Uses.front();
+          Fixup.Offset += F.BaseOffset;
+          // Add the new offset to LUThatHas' offset list.
+          if (LUThatHas->Offsets.back() != Fixup.Offset) {
+            LUThatHas->Offsets.push_back(Fixup.Offset);
+            if (Fixup.Offset > LUThatHas->MaxOffset)
+              LUThatHas->MaxOffset = Fixup.Offset;
+            if (Fixup.Offset < LUThatHas->MinOffset)
+              LUThatHas->MinOffset = Fixup.Offset;
           }
+          DEBUG(dbgs() << "New fixup has offset " << Fixup.Offset << '\n');
         }
+        if (Fixup.LUIdx == NumUses-1)
+          Fixup.LUIdx = LUIdx;
       }
-    }
 
-    DEBUG(dbgs() << "After pre-selection:\n";
-          print_uses(dbgs()));
+      // Delete formulae from the new use which are no longer legal.
+      bool Any = false;
+      for (size_t i = 0, e = LUThatHas->Formulae.size(); i != e; ++i) {
+        Formula &F = LUThatHas->Formulae[i];
+        if (!isLegalUse(TTI, LUThatHas->MinOffset, LUThatHas->MaxOffset,
+                        LUThatHas->Kind, LUThatHas->AccessTy, F)) {
+          DEBUG(dbgs() << "  Deleting "; F.print(dbgs());
+                dbgs() << '\n');
+          LUThatHas->DeleteFormula(F);
+          --i;
+          --e;
+          Any = true;
+        }
+      }
+
+      if (Any)
+        LUThatHas->RecomputeRegs(LUThatHas - &Uses.front(), RegUses);
+
+      // Delete the old use.
+      DeleteUse(LU, LUIdx);
+      --LUIdx;
+      --NumUses;
+      break;
+    }
   }
+
+  DEBUG(dbgs() << "After pre-selection:\n"; print_uses(dbgs()));
 }
 
 /// NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters - Call
diff --git a/lib/Transforms/Scalar/LoopUnrollPass.cpp b/lib/Transforms/Scalar/LoopUnrollPass.cpp
index e0f915b..80d060b 100644
--- a/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -17,6 +17,7 @@
 #include "llvm/Analysis/CodeMetrics.h"
 #include "llvm/Analysis/LoopPass.h"
 #include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/Support/CommandLine.h"
@@ -90,6 +91,7 @@ namespace {
       AU.addPreservedID(LCSSAID);
       AU.addRequired<ScalarEvolution>();
       AU.addPreserved<ScalarEvolution>();
+      AU.addRequired<TargetTransformInfo>();
       // FIXME: Loop unroll requires LCSSA. And LCSSA requires dom info.
       // If loop unroll does not preserve dom info then LCSSA pass on next
       // loop will receive invalid dom info.
@@ -101,6 +103,7 @@ namespace {
 
 char LoopUnroll::ID = 0;
 INITIALIZE_PASS_BEGIN(LoopUnroll, "loop-unroll", "Unroll loops", false, false)
+INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
 INITIALIZE_PASS_DEPENDENCY(LoopInfo)
 INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
 INITIALIZE_PASS_DEPENDENCY(LCSSA)
@@ -113,11 +116,12 @@ Pass *llvm::createLoopUnrollPass(int Threshold, int Count, int AllowPartial) {
 
 /// ApproximateLoopSize - Approximate the size of the loop.
 static unsigned ApproximateLoopSize(const Loop *L, unsigned &NumCalls,
-                                    bool &NotDuplicatable, const DataLayout *TD) {
+                                    bool &NotDuplicatable,
+                                    const TargetTransformInfo &TTI) {
   CodeMetrics Metrics;
   for (Loop::block_iterator I = L->block_begin(), E = L->block_end();
        I != E; ++I)
-    Metrics.analyzeBasicBlock(*I, TD);
+    Metrics.analyzeBasicBlock(*I, TTI);
   NumCalls = Metrics.NumInlineCandidates;
   NotDuplicatable = Metrics.notDuplicatable;
 
@@ -134,6 +138,7 @@ static unsigned ApproximateLoopSize(const Loop *L, unsigned &NumCalls,
 bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) {
   LoopInfo *LI = &getAnalysis<LoopInfo>();
   ScalarEvolution *SE = &getAnalysis<ScalarEvolution>();
+  const TargetTransformInfo &TTI = getAnalysis<TargetTransformInfo>();
 
   BasicBlock *Header = L->getHeader();
   DEBUG(dbgs() << "Loop Unroll: F[" << Header->getParent()->getName()
@@ -181,11 +186,10 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) {
 
   // Enforce the threshold.
   if (Threshold != NoThreshold) {
-    const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
     unsigned NumInlineCandidates;
     bool notDuplicatable;
     unsigned LoopSize = ApproximateLoopSize(L, NumInlineCandidates,
-                                            notDuplicatable, TD);
+                                            notDuplicatable, TTI);
     DEBUG(dbgs() << "  Loop Size = " << LoopSize << "\n");
     if (notDuplicatable) {
       DEBUG(dbgs() << "  Not unrolling loop which contains non duplicatable"
diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp
index 68d4423..0e8199f 100644
--- a/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -37,6 +37,7 @@
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/LoopPass.h"
 #include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
@@ -101,7 +102,7 @@ namespace {
 
       // Analyze loop. Check its size, calculate is it possible to unswitch
       // it. Returns true if we can unswitch this loop.
-      bool countLoop(const Loop* L);
+      bool countLoop(const Loop* L, const TargetTransformInfo &TTI);
 
       // Clean all data related to given loop.
       void forgetLoop(const Loop* L);
@@ -170,6 +171,7 @@ namespace {
       AU.addPreservedID(LCSSAID);
       AU.addPreserved<DominatorTree>();
       AU.addPreserved<ScalarEvolution>();
+      AU.addRequired<TargetTransformInfo>();
     }
 
   private:
@@ -221,7 +223,7 @@ namespace {
 
 // Analyze loop. Check its size, calculate is it possible to unswitch
 // it. Returns true if we can unswitch this loop.
-bool LUAnalysisCache::countLoop(const Loop* L) {
+bool LUAnalysisCache::countLoop(const Loop *L, const TargetTransformInfo &TTI) {
 
   std::pair<LoopPropsMapIt, bool> InsertRes =
       LoopsProperties.insert(std::make_pair(L, LoopProperties()));
@@ -243,7 +245,7 @@ bool LUAnalysisCache::countLoop(const Loop* L) {
     for (Loop::block_iterator I = L->block_begin(),
            E = L->block_end();
          I != E; ++I)
-      Metrics.analyzeBasicBlock(*I);
+      Metrics.analyzeBasicBlock(*I, TTI);
 
     Props.SizeEstimation = std::min(Metrics.NumInsts, Metrics.NumBlocks * 5);
     Props.CanBeUnswitchedCount = MaxSize / (Props.SizeEstimation);
@@ -334,6 +336,7 @@ void LUAnalysisCache::cloneData(const Loop* NewLoop, const Loop* OldLoop,
 char LoopUnswitch::ID = 0;
 INITIALIZE_PASS_BEGIN(LoopUnswitch, "loop-unswitch", "Unswitch loops",
                       false, false)
+INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
 INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
 INITIALIZE_PASS_DEPENDENCY(LoopInfo)
 INITIALIZE_PASS_DEPENDENCY(LCSSA)
@@ -424,7 +427,7 @@ bool LoopUnswitch::processCurrentLoop() {
 
   // Probably we reach the quota of branches for this loop. If so
   // stop unswitching.
-  if (!BranchesInfo.countLoop(currentLoop))
+  if (!BranchesInfo.countLoop(currentLoop, getAnalysis<TargetTransformInfo>()))
     return false;
 
   // Loop over all of the basic blocks in the loop.  If we find an interior
diff --git a/lib/Transforms/Scalar/ObjCARC.cpp b/lib/Transforms/Scalar/ObjCARC.cpp
deleted file mode 100644
index e6ec841..0000000
--- a/lib/Transforms/Scalar/ObjCARC.cpp
+++ /dev/null
@@ -1,4354 +0,0 @@
-//===- ObjCARC.cpp - ObjC ARC Optimization --------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file defines ObjC ARC optimizations. ARC stands for
-// Automatic Reference Counting and is a system for managing reference counts
-// for objects in Objective C.
-//
-// The optimizations performed include elimination of redundant, partially
-// redundant, and inconsequential reference count operations, elimination of
-// redundant weak pointer operations, pattern-matching and replacement of
-// low-level operations into higher-level operations, and numerous minor
-// simplifications.
-//
-// This file also defines a simple ARC-aware AliasAnalysis.
-//
-// WARNING: This file knows about certain library functions. It recognizes them
-// by name, and hardwires knowledge of their semantics.
-//
-// WARNING: This file knows about how certain Objective-C library functions are
-// used. Naive LLVM IR transformations which would otherwise be
-// behavior-preserving may break these assumptions.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "objc-arc"
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-using namespace llvm;
-
-// A handy option to enable/disable all optimizations in this file.
-static cl::opt<bool> EnableARCOpts("enable-objc-arc-opts", cl::init(true));
-
-//===----------------------------------------------------------------------===//
-// Misc. Utilities
-//===----------------------------------------------------------------------===//
-
-namespace {
-  /// MapVector - An associative container with fast insertion-order
-  /// (deterministic) iteration over its elements. Plus the special
-  /// blot operation.
-  template<class KeyT, class ValueT>
-  class MapVector {
-    /// Map - Map keys to indices in Vector.
-    typedef DenseMap<KeyT, size_t> MapTy;
-    MapTy Map;
-
-    /// Vector - Keys and values.
-    typedef std::vector<std::pair<KeyT, ValueT> > VectorTy;
-    VectorTy Vector;
-
-  public:
-    typedef typename VectorTy::iterator iterator;
-    typedef typename VectorTy::const_iterator const_iterator;
-    iterator begin() { return Vector.begin(); }
-    iterator end() { return Vector.end(); }
-    const_iterator begin() const { return Vector.begin(); }
-    const_iterator end() const { return Vector.end(); }
-
-#ifdef XDEBUG
-    ~MapVector() {
-      assert(Vector.size() >= Map.size()); // May differ due to blotting.
-      for (typename MapTy::const_iterator I = Map.begin(), E = Map.end();
-           I != E; ++I) {
-        assert(I->second < Vector.size());
-        assert(Vector[I->second].first == I->first);
-      }
-      for (typename VectorTy::const_iterator I = Vector.begin(),
-           E = Vector.end(); I != E; ++I)
-        assert(!I->first ||
-               (Map.count(I->first) &&
-                Map[I->first] == size_t(I - Vector.begin())));
-    }
-#endif
-
-    ValueT &operator[](const KeyT &Arg) {
-      std::pair<typename MapTy::iterator, bool> Pair =
-        Map.insert(std::make_pair(Arg, size_t(0)));
-      if (Pair.second) {
-        size_t Num = Vector.size();
-        Pair.first->second = Num;
-        Vector.push_back(std::make_pair(Arg, ValueT()));
-        return Vector[Num].second;
-      }
-      return Vector[Pair.first->second].second;
-    }
-
-    std::pair<iterator, bool>
-    insert(const std::pair<KeyT, ValueT> &InsertPair) {
-      std::pair<typename MapTy::iterator, bool> Pair =
-        Map.insert(std::make_pair(InsertPair.first, size_t(0)));
-      if (Pair.second) {
-        size_t Num = Vector.size();
-        Pair.first->second = Num;
-        Vector.push_back(InsertPair);
-        return std::make_pair(Vector.begin() + Num, true);
-      }
-      return std::make_pair(Vector.begin() + Pair.first->second, false);
-    }
-
-    const_iterator find(const KeyT &Key) const {
-      typename MapTy::const_iterator It = Map.find(Key);
-      if (It == Map.end()) return Vector.end();
-      return Vector.begin() + It->second;
-    }
-
-    /// blot - This is similar to erase, but instead of removing the element
-    /// from the vector, it just zeros out the key in the vector. This leaves
-    /// iterators intact, but clients must be prepared for zeroed-out keys when
-    /// iterating.
-    void blot(const KeyT &Key) {
-      typename MapTy::iterator It = Map.find(Key);
-      if (It == Map.end()) return;
-      Vector[It->second].first = KeyT();
-      Map.erase(It);
-    }
-
-    void clear() {
-      Map.clear();
-      Vector.clear();
-    }
-  };
-}
-
-//===----------------------------------------------------------------------===//
-// ARC Utilities.
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ADT/StringSwitch.h"
-#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/IR/Intrinsics.h"
-#include "llvm/IR/Module.h"
-#include "llvm/Support/CallSite.h"
-#include "llvm/Transforms/Utils/Local.h"
-
-namespace {
-  /// InstructionClass - A simple classification for instructions.
-  enum InstructionClass {
-    IC_Retain,              ///< objc_retain
-    IC_RetainRV,            ///< objc_retainAutoreleasedReturnValue
-    IC_RetainBlock,         ///< objc_retainBlock
-    IC_Release,             ///< objc_release
-    IC_Autorelease,         ///< objc_autorelease
-    IC_AutoreleaseRV,       ///< objc_autoreleaseReturnValue
-    IC_AutoreleasepoolPush, ///< objc_autoreleasePoolPush
-    IC_AutoreleasepoolPop,  ///< objc_autoreleasePoolPop
-    IC_NoopCast,            ///< objc_retainedObject, etc.
-    IC_FusedRetainAutorelease, ///< objc_retainAutorelease
-    IC_FusedRetainAutoreleaseRV, ///< objc_retainAutoreleaseReturnValue
-    IC_LoadWeakRetained,    ///< objc_loadWeakRetained (primitive)
-    IC_StoreWeak,           ///< objc_storeWeak (primitive)
-    IC_InitWeak,            ///< objc_initWeak (derived)
-    IC_LoadWeak,            ///< objc_loadWeak (derived)
-    IC_MoveWeak,            ///< objc_moveWeak (derived)
-    IC_CopyWeak,            ///< objc_copyWeak (derived)
-    IC_DestroyWeak,         ///< objc_destroyWeak (derived)
-    IC_StoreStrong,         ///< objc_storeStrong (derived)
-    IC_CallOrUser,          ///< could call objc_release and/or "use" pointers
-    IC_Call,                ///< could call objc_release
-    IC_User,                ///< could "use" a pointer
-    IC_None                 ///< anything else
-  };
-}
-
-/// IsPotentialUse - Test whether the given value is possible a
-/// reference-counted pointer.
-static bool IsPotentialUse(const Value *Op) {
-  // Pointers to static or stack storage are not reference-counted pointers.
-  if (isa<Constant>(Op) || isa<AllocaInst>(Op))
-    return false;
-  // Special arguments are not reference-counted.
-  if (const Argument *Arg = dyn_cast<Argument>(Op))
-    if (Arg->hasByValAttr() ||
-        Arg->hasNestAttr() ||
-        Arg->hasStructRetAttr())
-      return false;
-  // Only consider values with pointer types.
-  // It seemes intuitive to exclude function pointer types as well, since
-  // functions are never reference-counted, however clang occasionally
-  // bitcasts reference-counted pointers to function-pointer type
-  // temporarily.
-  PointerType *Ty = dyn_cast<PointerType>(Op->getType());
-  if (!Ty)
-    return false;
-  // Conservatively assume anything else is a potential use.
-  return true;
-}
-
-/// GetCallSiteClass - Helper for GetInstructionClass. Determines what kind
-/// of construct CS is.
-static InstructionClass GetCallSiteClass(ImmutableCallSite CS) {
-  for (ImmutableCallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
-       I != E; ++I)
-    if (IsPotentialUse(*I))
-      return CS.onlyReadsMemory() ? IC_User : IC_CallOrUser;
-
-  return CS.onlyReadsMemory() ? IC_None : IC_Call;
-}
-
-/// GetFunctionClass - Determine if F is one of the special known Functions.
-/// If it isn't, return IC_CallOrUser.
-static InstructionClass GetFunctionClass(const Function *F) {
-  Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
-
-  // No arguments.
-  if (AI == AE)
-    return StringSwitch<InstructionClass>(F->getName())
-      .Case("objc_autoreleasePoolPush",  IC_AutoreleasepoolPush)
-      .Default(IC_CallOrUser);
-
-  // One argument.
-  const Argument *A0 = AI++;
-  if (AI == AE)
-    // Argument is a pointer.
-    if (PointerType *PTy = dyn_cast<PointerType>(A0->getType())) {
-      Type *ETy = PTy->getElementType();
-      // Argument is i8*.
-      if (ETy->isIntegerTy(8))
-        return StringSwitch<InstructionClass>(F->getName())
-          .Case("objc_retain",                IC_Retain)
-          .Case("objc_retainAutoreleasedReturnValue", IC_RetainRV)
-          .Case("objc_retainBlock",           IC_RetainBlock)
-          .Case("objc_release",               IC_Release)
-          .Case("objc_autorelease",           IC_Autorelease)
-          .Case("objc_autoreleaseReturnValue", IC_AutoreleaseRV)
-          .Case("objc_autoreleasePoolPop",    IC_AutoreleasepoolPop)
-          .Case("objc_retainedObject",        IC_NoopCast)
-          .Case("objc_unretainedObject",      IC_NoopCast)
-          .Case("objc_unretainedPointer",     IC_NoopCast)
-          .Case("objc_retain_autorelease",    IC_FusedRetainAutorelease)
-          .Case("objc_retainAutorelease",     IC_FusedRetainAutorelease)
-          .Case("objc_retainAutoreleaseReturnValue",IC_FusedRetainAutoreleaseRV)
-          .Default(IC_CallOrUser);
-
-      // Argument is i8**
-      if (PointerType *Pte = dyn_cast<PointerType>(ETy))
-        if (Pte->getElementType()->isIntegerTy(8))
-          return StringSwitch<InstructionClass>(F->getName())
-            .Case("objc_loadWeakRetained",      IC_LoadWeakRetained)
-            .Case("objc_loadWeak",              IC_LoadWeak)
-            .Case("objc_destroyWeak",           IC_DestroyWeak)
-            .Default(IC_CallOrUser);
-    }
-
-  // Two arguments, first is i8**.
-  const Argument *A1 = AI++;
-  if (AI == AE)
-    if (PointerType *PTy = dyn_cast<PointerType>(A0->getType()))
-      if (PointerType *Pte = dyn_cast<PointerType>(PTy->getElementType()))
-        if (Pte->getElementType()->isIntegerTy(8))
-          if (PointerType *PTy1 = dyn_cast<PointerType>(A1->getType())) {
-            Type *ETy1 = PTy1->getElementType();
-            // Second argument is i8*
-            if (ETy1->isIntegerTy(8))
-              return StringSwitch<InstructionClass>(F->getName())
-                     .Case("objc_storeWeak",             IC_StoreWeak)
-                     .Case("objc_initWeak",              IC_InitWeak)
-                     .Case("objc_storeStrong",           IC_StoreStrong)
-                     .Default(IC_CallOrUser);
-            // Second argument is i8**.
-            if (PointerType *Pte1 = dyn_cast<PointerType>(ETy1))
-              if (Pte1->getElementType()->isIntegerTy(8))
-                return StringSwitch<InstructionClass>(F->getName())
-                       .Case("objc_moveWeak",              IC_MoveWeak)
-                       .Case("objc_copyWeak",              IC_CopyWeak)
-                       .Default(IC_CallOrUser);
-          }
-
-  // Anything else.
-  return IC_CallOrUser;
-}
-
-/// GetInstructionClass - Determine what kind of construct V is.
-static InstructionClass GetInstructionClass(const Value *V) {
-  if (const Instruction *I = dyn_cast<Instruction>(V)) {
-    // Any instruction other than bitcast and gep with a pointer operand have a
-    // use of an objc pointer. Bitcasts, GEPs, Selects, PHIs transfer a pointer
-    // to a subsequent use, rather than using it themselves, in this sense.
-    // As a short cut, several other opcodes are known to have no pointer
-    // operands of interest. And ret is never followed by a release, so it's
-    // not interesting to examine.
-    switch (I->getOpcode()) {
-    case Instruction::Call: {
-      const CallInst *CI = cast<CallInst>(I);
-      // Check for calls to special functions.
-      if (const Function *F = CI->getCalledFunction()) {
-        InstructionClass Class = GetFunctionClass(F);
-        if (Class != IC_CallOrUser)
-          return Class;
-
-        // None of the intrinsic functions do objc_release. For intrinsics, the
-        // only question is whether or not they may be users.
-        switch (F->getIntrinsicID()) {
-        case Intrinsic::returnaddress: case Intrinsic::frameaddress:
-        case Intrinsic::stacksave: case Intrinsic::stackrestore:
-        case Intrinsic::vastart: case Intrinsic::vacopy: case Intrinsic::vaend:
-        case Intrinsic::objectsize: case Intrinsic::prefetch:
-        case Intrinsic::stackprotector:
-        case Intrinsic::eh_return_i32: case Intrinsic::eh_return_i64:
-        case Intrinsic::eh_typeid_for: case Intrinsic::eh_dwarf_cfa:
-        case Intrinsic::eh_sjlj_lsda: case Intrinsic::eh_sjlj_functioncontext:
-        case Intrinsic::init_trampoline: case Intrinsic::adjust_trampoline:
-        case Intrinsic::lifetime_start: case Intrinsic::lifetime_end:
-        case Intrinsic::invariant_start: case Intrinsic::invariant_end:
-        // Don't let dbg info affect our results.
-        case Intrinsic::dbg_declare: case Intrinsic::dbg_value:
-          // Short cut: Some intrinsics obviously don't use ObjC pointers.
-          return IC_None;
-        default:
-          break;
-        }
-      }
-      return GetCallSiteClass(CI);
-    }
-    case Instruction::Invoke:
-      return GetCallSiteClass(cast<InvokeInst>(I));
-    case Instruction::BitCast:
-    case Instruction::GetElementPtr:
-    case Instruction::Select: case Instruction::PHI:
-    case Instruction::Ret: case Instruction::Br:
-    case Instruction::Switch: case Instruction::IndirectBr:
-    case Instruction::Alloca: case Instruction::VAArg:
-    case Instruction::Add: case Instruction::FAdd:
-    case Instruction::Sub: case Instruction::FSub:
-    case Instruction::Mul: case Instruction::FMul:
-    case Instruction::SDiv: case Instruction::UDiv: case Instruction::FDiv:
-    case Instruction::SRem: case Instruction::URem: case Instruction::FRem:
-    case Instruction::Shl: case Instruction::LShr: case Instruction::AShr:
-    case Instruction::And: case Instruction::Or: case Instruction::Xor:
-    case Instruction::SExt: case Instruction::ZExt: case Instruction::Trunc:
-    case Instruction::IntToPtr: case Instruction::FCmp:
-    case Instruction::FPTrunc: case Instruction::FPExt:
-    case Instruction::FPToUI: case Instruction::FPToSI:
-    case Instruction::UIToFP: case Instruction::SIToFP:
-    case Instruction::InsertElement: case Instruction::ExtractElement:
-    case Instruction::ShuffleVector:
-    case Instruction::ExtractValue:
-      break;
-    case Instruction::ICmp:
-      // Comparing a pointer with null, or any other constant, isn't an
-      // interesting use, because we don't care what the pointer points to, or
-      // about the values of any other dynamic reference-counted pointers.
-      if (IsPotentialUse(I->getOperand(1)))
-        return IC_User;
-      break;
-    default:
-      // For anything else, check all the operands.
-      // Note that this includes both operands of a Store: while the first
-      // operand isn't actually being dereferenced, it is being stored to
-      // memory where we can no longer track who might read it and dereference
-      // it, so we have to consider it potentially used.
-      for (User::const_op_iterator OI = I->op_begin(), OE = I->op_end();
-           OI != OE; ++OI)
-        if (IsPotentialUse(*OI))
-          return IC_User;
-    }
-  }
-
-  // Otherwise, it's totally inert for ARC purposes.
-  return IC_None;
-}
-
-/// GetBasicInstructionClass - Determine what kind of construct V is. This is
-/// similar to GetInstructionClass except that it only detects objc runtine
-/// calls. This allows it to be faster.
-static InstructionClass GetBasicInstructionClass(const Value *V) {
-  if (const CallInst *CI = dyn_cast<CallInst>(V)) {
-    if (const Function *F = CI->getCalledFunction())
-      return GetFunctionClass(F);
-    // Otherwise, be conservative.
-    return IC_CallOrUser;
-  }
-
-  // Otherwise, be conservative.
-  return isa<InvokeInst>(V) ? IC_CallOrUser : IC_User;
-}
-
-/// IsRetain - Test if the given class is objc_retain or
-/// equivalent.
-static bool IsRetain(InstructionClass Class) {
-  return Class == IC_Retain ||
-         Class == IC_RetainRV;
-}
-
-/// IsAutorelease - Test if the given class is objc_autorelease or
-/// equivalent.
-static bool IsAutorelease(InstructionClass Class) {
-  return Class == IC_Autorelease ||
-         Class == IC_AutoreleaseRV;
-}
-
-/// IsForwarding - Test if the given class represents instructions which return
-/// their argument verbatim.
-static bool IsForwarding(InstructionClass Class) {
-  // objc_retainBlock technically doesn't always return its argument
-  // verbatim, but it doesn't matter for our purposes here.
-  return Class == IC_Retain ||
-         Class == IC_RetainRV ||
-         Class == IC_Autorelease ||
-         Class == IC_AutoreleaseRV ||
-         Class == IC_RetainBlock ||
-         Class == IC_NoopCast;
-}
-
-/// IsNoopOnNull - Test if the given class represents instructions which do
-/// nothing if passed a null pointer.
-static bool IsNoopOnNull(InstructionClass Class) {
-  return Class == IC_Retain ||
-         Class == IC_RetainRV ||
-         Class == IC_Release ||
-         Class == IC_Autorelease ||
-         Class == IC_AutoreleaseRV ||
-         Class == IC_RetainBlock;
-}
-
-/// IsAlwaysTail - Test if the given class represents instructions which are
-/// always safe to mark with the "tail" keyword.
-static bool IsAlwaysTail(InstructionClass Class) {
-  // IC_RetainBlock may be given a stack argument.
-  return Class == IC_Retain ||
-         Class == IC_RetainRV ||
-         Class == IC_Autorelease ||
-         Class == IC_AutoreleaseRV;
-}
-
-/// IsNoThrow - Test if the given class represents instructions which are always
-/// safe to mark with the nounwind attribute..
-static bool IsNoThrow(InstructionClass Class) {
-  // objc_retainBlock is not nounwind because it calls user copy constructors
-  // which could theoretically throw.
-  return Class == IC_Retain ||
-         Class == IC_RetainRV ||
-         Class == IC_Release ||
-         Class == IC_Autorelease ||
-         Class == IC_AutoreleaseRV ||
-         Class == IC_AutoreleasepoolPush ||
-         Class == IC_AutoreleasepoolPop;
-}
-
-/// EraseInstruction - Erase the given instruction. Many ObjC calls return their
-/// argument verbatim, so if it's such a call and the return value has users,
-/// replace them with the argument value.
-static void EraseInstruction(Instruction *CI) {
-  Value *OldArg = cast<CallInst>(CI)->getArgOperand(0);
-
-  bool Unused = CI->use_empty();
-
-  if (!Unused) {
-    // Replace the return value with the argument.
-    assert(IsForwarding(GetBasicInstructionClass(CI)) &&
-           "Can't delete non-forwarding instruction with users!");
-    CI->replaceAllUsesWith(OldArg);
-  }
-
-  CI->eraseFromParent();
-
-  if (Unused)
-    RecursivelyDeleteTriviallyDeadInstructions(OldArg);
-}
-
-/// GetUnderlyingObjCPtr - This is a wrapper around getUnderlyingObject which
-/// also knows how to look through objc_retain and objc_autorelease calls, which
-/// we know to return their argument verbatim.
-static const Value *GetUnderlyingObjCPtr(const Value *V) {
-  for (;;) {
-    V = GetUnderlyingObject(V);
-    if (!IsForwarding(GetBasicInstructionClass(V)))
-      break;
-    V = cast<CallInst>(V)->getArgOperand(0);
-  }
-
-  return V;
-}
-
-/// StripPointerCastsAndObjCCalls - This is a wrapper around
-/// Value::stripPointerCasts which also knows how to look through objc_retain
-/// and objc_autorelease calls, which we know to return their argument verbatim.
-static const Value *StripPointerCastsAndObjCCalls(const Value *V) {
-  for (;;) {
-    V = V->stripPointerCasts();
-    if (!IsForwarding(GetBasicInstructionClass(V)))
-      break;
-    V = cast<CallInst>(V)->getArgOperand(0);
-  }
-  return V;
-}
-
-/// StripPointerCastsAndObjCCalls - This is a wrapper around
-/// Value::stripPointerCasts which also knows how to look through objc_retain
-/// and objc_autorelease calls, which we know to return their argument verbatim.
-static Value *StripPointerCastsAndObjCCalls(Value *V) {
-  for (;;) {
-    V = V->stripPointerCasts();
-    if (!IsForwarding(GetBasicInstructionClass(V)))
-      break;
-    V = cast<CallInst>(V)->getArgOperand(0);
-  }
-  return V;
-}
-
-/// GetObjCArg - Assuming the given instruction is one of the special calls such
-/// as objc_retain or objc_release, return the argument value, stripped of no-op
-/// casts and forwarding calls.
-static Value *GetObjCArg(Value *Inst) {
-  return StripPointerCastsAndObjCCalls(cast<CallInst>(Inst)->getArgOperand(0));
-}
-
-/// IsObjCIdentifiedObject - This is similar to AliasAnalysis'
-/// isObjCIdentifiedObject, except that it uses special knowledge of
-/// ObjC conventions...
-static bool IsObjCIdentifiedObject(const Value *V) {
-  // Assume that call results and arguments have their own "provenance".
-  // Constants (including GlobalVariables) and Allocas are never
-  // reference-counted.
-  if (isa<CallInst>(V) || isa<InvokeInst>(V) ||
-      isa<Argument>(V) || isa<Constant>(V) ||
-      isa<AllocaInst>(V))
-    return true;
-
-  if (const LoadInst *LI = dyn_cast<LoadInst>(V)) {
-    const Value *Pointer =
-      StripPointerCastsAndObjCCalls(LI->getPointerOperand());
-    if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(Pointer)) {
-      // A constant pointer can't be pointing to an object on the heap. It may
-      // be reference-counted, but it won't be deleted.
-      if (GV->isConstant())
-        return true;
-      StringRef Name = GV->getName();
-      // These special variables are known to hold values which are not
-      // reference-counted pointers.
-      if (Name.startswith("\01L_OBJC_SELECTOR_REFERENCES_") ||
-          Name.startswith("\01L_OBJC_CLASSLIST_REFERENCES_") ||
-          Name.startswith("\01L_OBJC_CLASSLIST_SUP_REFS_$_") ||
-          Name.startswith("\01L_OBJC_METH_VAR_NAME_") ||
-          Name.startswith("\01l_objc_msgSend_fixup_"))
-        return true;
-    }
-  }
-
-  return false;
-}
-
-/// FindSingleUseIdentifiedObject - This is similar to
-/// StripPointerCastsAndObjCCalls but it stops as soon as it finds a value
-/// with multiple uses.
-static const Value *FindSingleUseIdentifiedObject(const Value *Arg) {
-  if (Arg->hasOneUse()) {
-    if (const BitCastInst *BC = dyn_cast<BitCastInst>(Arg))
-      return FindSingleUseIdentifiedObject(BC->getOperand(0));
-    if (const GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Arg))
-      if (GEP->hasAllZeroIndices())
-        return FindSingleUseIdentifiedObject(GEP->getPointerOperand());
-    if (IsForwarding(GetBasicInstructionClass(Arg)))
-      return FindSingleUseIdentifiedObject(
-               cast<CallInst>(Arg)->getArgOperand(0));
-    if (!IsObjCIdentifiedObject(Arg))
-      return 0;
-    return Arg;
-  }
-
-  // If we found an identifiable object but it has multiple uses, but they are
-  // trivial uses, we can still consider this to be a single-use value.
-  if (IsObjCIdentifiedObject(Arg)) {
-    for (Value::const_use_iterator UI = Arg->use_begin(), UE = Arg->use_end();
-         UI != UE; ++UI) {
-      const User *U = *UI;
-      if (!U->use_empty() || StripPointerCastsAndObjCCalls(U) != Arg)
-         return 0;
-    }
-
-    return Arg;
-  }
-
-  return 0;
-}
-
-/// ModuleHasARC - Test if the given module looks interesting to run ARC
-/// optimization on.
-static bool ModuleHasARC(const Module &M) {
-  return
-    M.getNamedValue("objc_retain") ||
-    M.getNamedValue("objc_release") ||
-    M.getNamedValue("objc_autorelease") ||
-    M.getNamedValue("objc_retainAutoreleasedReturnValue") ||
-    M.getNamedValue("objc_retainBlock") ||
-    M.getNamedValue("objc_autoreleaseReturnValue") ||
-    M.getNamedValue("objc_autoreleasePoolPush") ||
-    M.getNamedValue("objc_loadWeakRetained") ||
-    M.getNamedValue("objc_loadWeak") ||
-    M.getNamedValue("objc_destroyWeak") ||
-    M.getNamedValue("objc_storeWeak") ||
-    M.getNamedValue("objc_initWeak") ||
-    M.getNamedValue("objc_moveWeak") ||
-    M.getNamedValue("objc_copyWeak") ||
-    M.getNamedValue("objc_retainedObject") ||
-    M.getNamedValue("objc_unretainedObject") ||
-    M.getNamedValue("objc_unretainedPointer");
-}
-
-/// DoesObjCBlockEscape - Test whether the given pointer, which is an
-/// Objective C block pointer, does not "escape". This differs from regular
-/// escape analysis in that a use as an argument to a call is not considered
-/// an escape.
-static bool DoesObjCBlockEscape(const Value *BlockPtr) {
-  // Walk the def-use chains.
-  SmallVector<const Value *, 4> Worklist;
-  Worklist.push_back(BlockPtr);
-  do {
-    const Value *V = Worklist.pop_back_val();
-    for (Value::const_use_iterator UI = V->use_begin(), UE = V->use_end();
-         UI != UE; ++UI) {
-      const User *UUser = *UI;
-      // Special - Use by a call (callee or argument) is not considered
-      // to be an escape.
-      switch (GetBasicInstructionClass(UUser)) {
-      case IC_StoreWeak:
-      case IC_InitWeak:
-      case IC_StoreStrong:
-      case IC_Autorelease:
-      case IC_AutoreleaseRV:
-        // These special functions make copies of their pointer arguments.
-        return true;
-      case IC_User:
-      case IC_None:
-        // Use by an instruction which copies the value is an escape if the
-        // result is an escape.
-        if (isa<BitCastInst>(UUser) || isa<GetElementPtrInst>(UUser) ||
-            isa<PHINode>(UUser) || isa<SelectInst>(UUser)) {
-          Worklist.push_back(UUser);
-          continue;
-        }
-        // Use by a load is not an escape.
-        if (isa<LoadInst>(UUser))
-          continue;
-        // Use by a store is not an escape if the use is the address.
-        if (const StoreInst *SI = dyn_cast<StoreInst>(UUser))
-          if (V != SI->getValueOperand())
-            continue;
-        break;
-      default:
-        // Regular calls and other stuff are not considered escapes.
-        continue;
-      }
-      // Otherwise, conservatively assume an escape.
-      return true;
-    }
-  } while (!Worklist.empty());
-
-  // No escapes found.
-  return false;
-}
-
-//===----------------------------------------------------------------------===//
-// ARC AliasAnalysis.
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Analysis/AliasAnalysis.h"
-#include "llvm/Analysis/Passes.h"
-#include "llvm/Pass.h"
-
-namespace {
-  /// ObjCARCAliasAnalysis - This is a simple alias analysis
-  /// implementation that uses knowledge of ARC constructs to answer queries.
-  ///
-  /// TODO: This class could be generalized to know about other ObjC-specific
-  /// tricks. Such as knowing that ivars in the non-fragile ABI are non-aliasing
-  /// even though their offsets are dynamic.
-  class ObjCARCAliasAnalysis : public ImmutablePass,
-                               public AliasAnalysis {
-  public:
-    static char ID; // Class identification, replacement for typeinfo
-    ObjCARCAliasAnalysis() : ImmutablePass(ID) {
-      initializeObjCARCAliasAnalysisPass(*PassRegistry::getPassRegistry());
-    }
-
-  private:
-    virtual void initializePass() {
-      InitializeAliasAnalysis(this);
-    }
-
-    /// getAdjustedAnalysisPointer - This method is used when a pass implements
-    /// an analysis interface through multiple inheritance.  If needed, it
-    /// should override this to adjust the this pointer as needed for the
-    /// specified pass info.
-    virtual void *getAdjustedAnalysisPointer(const void *PI) {
-      if (PI == &AliasAnalysis::ID)
-        return static_cast<AliasAnalysis *>(this);
-      return this;
-    }
-
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
-    virtual AliasResult alias(const Location &LocA, const Location &LocB);
-    virtual bool pointsToConstantMemory(const Location &Loc, bool OrLocal);
-    virtual ModRefBehavior getModRefBehavior(ImmutableCallSite CS);
-    virtual ModRefBehavior getModRefBehavior(const Function *F);
-    virtual ModRefResult getModRefInfo(ImmutableCallSite CS,
-                                       const Location &Loc);
-    virtual ModRefResult getModRefInfo(ImmutableCallSite CS1,
-                                       ImmutableCallSite CS2);
-  };
-}  // End of anonymous namespace
-
-// Register this pass...
-char ObjCARCAliasAnalysis::ID = 0;
-INITIALIZE_AG_PASS(ObjCARCAliasAnalysis, AliasAnalysis, "objc-arc-aa",
-                   "ObjC-ARC-Based Alias Analysis", false, true, false)
-
-ImmutablePass *llvm::createObjCARCAliasAnalysisPass() {
-  return new ObjCARCAliasAnalysis();
-}
-
-void
-ObjCARCAliasAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.setPreservesAll();
-  AliasAnalysis::getAnalysisUsage(AU);
-}
-
-AliasAnalysis::AliasResult
-ObjCARCAliasAnalysis::alias(const Location &LocA, const Location &LocB) {
-  if (!EnableARCOpts)
-    return AliasAnalysis::alias(LocA, LocB);
-
-  // First, strip off no-ops, including ObjC-specific no-ops, and try making a
-  // precise alias query.
-  const Value *SA = StripPointerCastsAndObjCCalls(LocA.Ptr);
-  const Value *SB = StripPointerCastsAndObjCCalls(LocB.Ptr);
-  AliasResult Result =
-    AliasAnalysis::alias(Location(SA, LocA.Size, LocA.TBAATag),
-                         Location(SB, LocB.Size, LocB.TBAATag));
-  if (Result != MayAlias)
-    return Result;
-
-  // If that failed, climb to the underlying object, including climbing through
-  // ObjC-specific no-ops, and try making an imprecise alias query.
-  const Value *UA = GetUnderlyingObjCPtr(SA);
-  const Value *UB = GetUnderlyingObjCPtr(SB);
-  if (UA != SA || UB != SB) {
-    Result = AliasAnalysis::alias(Location(UA), Location(UB));
-    // We can't use MustAlias or PartialAlias results here because
-    // GetUnderlyingObjCPtr may return an offsetted pointer value.
-    if (Result == NoAlias)
-      return NoAlias;
-  }
-
-  // If that failed, fail. We don't need to chain here, since that's covered
-  // by the earlier precise query.
-  return MayAlias;
-}
-
-bool
-ObjCARCAliasAnalysis::pointsToConstantMemory(const Location &Loc,
-                                             bool OrLocal) {
-  if (!EnableARCOpts)
-    return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
-
-  // First, strip off no-ops, including ObjC-specific no-ops, and try making
-  // a precise alias query.
-  const Value *S = StripPointerCastsAndObjCCalls(Loc.Ptr);
-  if (AliasAnalysis::pointsToConstantMemory(Location(S, Loc.Size, Loc.TBAATag),
-                                            OrLocal))
-    return true;
-
-  // If that failed, climb to the underlying object, including climbing through
-  // ObjC-specific no-ops, and try making an imprecise alias query.
-  const Value *U = GetUnderlyingObjCPtr(S);
-  if (U != S)
-    return AliasAnalysis::pointsToConstantMemory(Location(U), OrLocal);
-
-  // If that failed, fail. We don't need to chain here, since that's covered
-  // by the earlier precise query.
-  return false;
-}
-
-AliasAnalysis::ModRefBehavior
-ObjCARCAliasAnalysis::getModRefBehavior(ImmutableCallSite CS) {
-  // We have nothing to do. Just chain to the next AliasAnalysis.
-  return AliasAnalysis::getModRefBehavior(CS);
-}
-
-AliasAnalysis::ModRefBehavior
-ObjCARCAliasAnalysis::getModRefBehavior(const Function *F) {
-  if (!EnableARCOpts)
-    return AliasAnalysis::getModRefBehavior(F);
-
-  switch (GetFunctionClass(F)) {
-  case IC_NoopCast:
-    return DoesNotAccessMemory;
-  default:
-    break;
-  }
-
-  return AliasAnalysis::getModRefBehavior(F);
-}
-
-AliasAnalysis::ModRefResult
-ObjCARCAliasAnalysis::getModRefInfo(ImmutableCallSite CS, const Location &Loc) {
-  if (!EnableARCOpts)
-    return AliasAnalysis::getModRefInfo(CS, Loc);
-
-  switch (GetBasicInstructionClass(CS.getInstruction())) {
-  case IC_Retain:
-  case IC_RetainRV:
-  case IC_Autorelease:
-  case IC_AutoreleaseRV:
-  case IC_NoopCast:
-  case IC_AutoreleasepoolPush:
-  case IC_FusedRetainAutorelease:
-  case IC_FusedRetainAutoreleaseRV:
-    // These functions don't access any memory visible to the compiler.
-    // Note that this doesn't include objc_retainBlock, because it updates
-    // pointers when it copies block data.
-    return NoModRef;
-  default:
-    break;
-  }
-
-  return AliasAnalysis::getModRefInfo(CS, Loc);
-}
-
-AliasAnalysis::ModRefResult
-ObjCARCAliasAnalysis::getModRefInfo(ImmutableCallSite CS1,
-                                    ImmutableCallSite CS2) {
-  // TODO: Theoretically we could check for dependencies between objc_* calls
-  // and OnlyAccessesArgumentPointees calls or other well-behaved calls.
-  return AliasAnalysis::getModRefInfo(CS1, CS2);
-}
-
-//===----------------------------------------------------------------------===//
-// ARC expansion.
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Support/InstIterator.h"
-#include "llvm/Transforms/Scalar.h"
-
-namespace {
-  /// ObjCARCExpand - Early ARC transformations.
-  class ObjCARCExpand : public FunctionPass {
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
-    virtual bool doInitialization(Module &M);
-    virtual bool runOnFunction(Function &F);
-
-    /// Run - A flag indicating whether this optimization pass should run.
-    bool Run;
-
-  public:
-    static char ID;
-    ObjCARCExpand() : FunctionPass(ID) {
-      initializeObjCARCExpandPass(*PassRegistry::getPassRegistry());
-    }
-  };
-}
-
-char ObjCARCExpand::ID = 0;
-INITIALIZE_PASS(ObjCARCExpand,
-                "objc-arc-expand", "ObjC ARC expansion", false, false)
-
-Pass *llvm::createObjCARCExpandPass() {
-  return new ObjCARCExpand();
-}
-
-void ObjCARCExpand::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.setPreservesCFG();
-}
-
-bool ObjCARCExpand::doInitialization(Module &M) {
-  Run = ModuleHasARC(M);
-  return false;
-}
-
-bool ObjCARCExpand::runOnFunction(Function &F) {
-  if (!EnableARCOpts)
-    return false;
-
-  // If nothing in the Module uses ARC, don't do anything.
-  if (!Run)
-    return false;
-
-  bool Changed = false;
-
-  for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ++I) {
-    Instruction *Inst = &*I;
-
-    DEBUG(dbgs() << "ObjCARCExpand: Visiting: " << *Inst << "\n");
-
-    switch (GetBasicInstructionClass(Inst)) {
-    case IC_Retain:
-    case IC_RetainRV:
-    case IC_Autorelease:
-    case IC_AutoreleaseRV:
-    case IC_FusedRetainAutorelease:
-    case IC_FusedRetainAutoreleaseRV: {
-      // These calls return their argument verbatim, as a low-level
-      // optimization. However, this makes high-level optimizations
-      // harder. Undo any uses of this optimization that the front-end
-      // emitted here. We'll redo them in the contract pass.
-      Changed = true;
-      Value *Value = cast<CallInst>(Inst)->getArgOperand(0);
-      DEBUG(dbgs() << "ObjCARCExpand: Old = " << *Inst << "\n"
-                      "               New = " << *Value << "\n");
-      Inst->replaceAllUsesWith(Value);
-      break;
-    }
-    default:
-      break;
-    }
-  }
-
-  DEBUG(dbgs() << "ObjCARCExpand: Finished List.\n\n");
-
-  return Changed;
-}
-
-//===----------------------------------------------------------------------===//
-// ARC autorelease pool elimination.
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ADT/STLExtras.h"
-#include "llvm/IR/Constants.h"
-
-namespace {
-  /// ObjCARCAPElim - Autorelease pool elimination.
-  class ObjCARCAPElim : public ModulePass {
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
-    virtual bool runOnModule(Module &M);
-
-    static bool MayAutorelease(ImmutableCallSite CS, unsigned Depth = 0);
-    static bool OptimizeBB(BasicBlock *BB);
-
-  public:
-    static char ID;
-    ObjCARCAPElim() : ModulePass(ID) {
-      initializeObjCARCAPElimPass(*PassRegistry::getPassRegistry());
-    }
-  };
-}
-
-char ObjCARCAPElim::ID = 0;
-INITIALIZE_PASS(ObjCARCAPElim,
-                "objc-arc-apelim",
-                "ObjC ARC autorelease pool elimination",
-                false, false)
-
-Pass *llvm::createObjCARCAPElimPass() {
-  return new ObjCARCAPElim();
-}
-
-void ObjCARCAPElim::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.setPreservesCFG();
-}
-
-/// MayAutorelease - Interprocedurally determine if calls made by the
-/// given call site can possibly produce autoreleases.
-bool ObjCARCAPElim::MayAutorelease(ImmutableCallSite CS, unsigned Depth) {
-  if (const Function *Callee = CS.getCalledFunction()) {
-    if (Callee->isDeclaration() || Callee->mayBeOverridden())
-      return true;
-    for (Function::const_iterator I = Callee->begin(), E = Callee->end();
-         I != E; ++I) {
-      const BasicBlock *BB = I;
-      for (BasicBlock::const_iterator J = BB->begin(), F = BB->end();
-           J != F; ++J)
-        if (ImmutableCallSite JCS = ImmutableCallSite(J))
-          // This recursion depth limit is arbitrary. It's just great
-          // enough to cover known interesting testcases.
-          if (Depth < 3 &&
-              !JCS.onlyReadsMemory() &&
-              MayAutorelease(JCS, Depth + 1))
-            return true;
-    }
-    return false;
-  }
-
-  return true;
-}
-
-bool ObjCARCAPElim::OptimizeBB(BasicBlock *BB) {
-  bool Changed = false;
-
-  Instruction *Push = 0;
-  for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
-    Instruction *Inst = I++;
-    switch (GetBasicInstructionClass(Inst)) {
-    case IC_AutoreleasepoolPush:
-      Push = Inst;
-      break;
-    case IC_AutoreleasepoolPop:
-      // If this pop matches a push and nothing in between can autorelease,
-      // zap the pair.
-      if (Push && cast<CallInst>(Inst)->getArgOperand(0) == Push) {
-        Changed = true;
-        DEBUG(dbgs() << "ObjCARCAPElim::OptimizeBB: Zapping push pop autorelease pair:\n"
-                     << "                           Pop: " << *Inst << "\n"
-                     << "                           Push: " << *Push << "\n");
-        Inst->eraseFromParent();
-        Push->eraseFromParent();
-      }
-      Push = 0;
-      break;
-    case IC_CallOrUser:
-      if (MayAutorelease(ImmutableCallSite(Inst)))
-        Push = 0;
-      break;
-    default:
-      break;
-    }
-  }
-
-  return Changed;
-}
-
-bool ObjCARCAPElim::runOnModule(Module &M) {
-  if (!EnableARCOpts)
-    return false;
-
-  // If nothing in the Module uses ARC, don't do anything.
-  if (!ModuleHasARC(M))
-    return false;
-
-  // Find the llvm.global_ctors variable, as the first step in
-  // identifying the global constructors. In theory, unnecessary autorelease
-  // pools could occur anywhere, but in practice it's pretty rare. Global
-  // ctors are a place where autorelease pools get inserted automatically,
-  // so it's pretty common for them to be unnecessary, and it's pretty
-  // profitable to eliminate them.
-  GlobalVariable *GV = M.getGlobalVariable("llvm.global_ctors");
-  if (!GV)
-    return false;
-
-  assert(GV->hasDefinitiveInitializer() &&
-         "llvm.global_ctors is uncooperative!");
-
-  bool Changed = false;
-
-  // Dig the constructor functions out of GV's initializer.
-  ConstantArray *Init = cast<ConstantArray>(GV->getInitializer());
-  for (User::op_iterator OI = Init->op_begin(), OE = Init->op_end();
-       OI != OE; ++OI) {
-    Value *Op = *OI;
-    // llvm.global_ctors is an array of pairs where the second members
-    // are constructor functions.
-    Function *F = dyn_cast<Function>(cast<ConstantStruct>(Op)->getOperand(1));
-    // If the user used a constructor function with the wrong signature and
-    // it got bitcasted or whatever, look the other way.
-    if (!F)
-      continue;
-    // Only look at function definitions.
-    if (F->isDeclaration())
-      continue;
-    // Only look at functions with one basic block.
-    if (llvm::next(F->begin()) != F->end())
-      continue;
-    // Ok, a single-block constructor function definition. Try to optimize it.
-    Changed |= OptimizeBB(F->begin());
-  }
-
-  return Changed;
-}
-
-//===----------------------------------------------------------------------===//
-// ARC optimization.
-//===----------------------------------------------------------------------===//
-
-// TODO: On code like this:
-//
-// objc_retain(%x)
-// stuff_that_cannot_release()
-// objc_autorelease(%x)
-// stuff_that_cannot_release()
-// objc_retain(%x)
-// stuff_that_cannot_release()
-// objc_autorelease(%x)
-//
-// The second retain and autorelease can be deleted.
-
-// TODO: It should be possible to delete
-// objc_autoreleasePoolPush and objc_autoreleasePoolPop
-// pairs if nothing is actually autoreleased between them. Also, autorelease
-// calls followed by objc_autoreleasePoolPop calls (perhaps in ObjC++ code
-// after inlining) can be turned into plain release calls.
-
-// TODO: Critical-edge splitting. If the optimial insertion point is
-// a critical edge, the current algorithm has to fail, because it doesn't
-// know how to split edges. It should be possible to make the optimizer
-// think in terms of edges, rather than blocks, and then split critical
-// edges on demand.
-
-// TODO: OptimizeSequences could generalized to be Interprocedural.
-
-// TODO: Recognize that a bunch of other objc runtime calls have
-// non-escaping arguments and non-releasing arguments, and may be
-// non-autoreleasing.
-
-// TODO: Sink autorelease calls as far as possible. Unfortunately we
-// usually can't sink them past other calls, which would be the main
-// case where it would be useful.
-
-// TODO: The pointer returned from objc_loadWeakRetained is retained.
-
-// TODO: Delete release+retain pairs (rare).
-
-#include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/Support/CFG.h"
-
-STATISTIC(NumNoops,       "Number of no-op objc calls eliminated");
-STATISTIC(NumPartialNoops, "Number of partially no-op objc calls eliminated");
-STATISTIC(NumAutoreleases,"Number of autoreleases converted to releases");
-STATISTIC(NumRets,        "Number of return value forwarding "
-                          "retain+autoreleaes eliminated");
-STATISTIC(NumRRs,         "Number of retain+release paths eliminated");
-STATISTIC(NumPeeps,       "Number of calls peephole-optimized");
-
-namespace {
-  /// ProvenanceAnalysis - This is similar to BasicAliasAnalysis, and it
-  /// uses many of the same techniques, except it uses special ObjC-specific
-  /// reasoning about pointer relationships.
-  class ProvenanceAnalysis {
-    AliasAnalysis *AA;
-
-    typedef std::pair<const Value *, const Value *> ValuePairTy;
-    typedef DenseMap<ValuePairTy, bool> CachedResultsTy;
-    CachedResultsTy CachedResults;
-
-    bool relatedCheck(const Value *A, const Value *B);
-    bool relatedSelect(const SelectInst *A, const Value *B);
-    bool relatedPHI(const PHINode *A, const Value *B);
-
-    void operator=(const ProvenanceAnalysis &) LLVM_DELETED_FUNCTION;
-    ProvenanceAnalysis(const ProvenanceAnalysis &) LLVM_DELETED_FUNCTION;
-
-  public:
-    ProvenanceAnalysis() {}
-
-    void setAA(AliasAnalysis *aa) { AA = aa; }
-
-    AliasAnalysis *getAA() const { return AA; }
-
-    bool related(const Value *A, const Value *B);
-
-    void clear() {
-      CachedResults.clear();
-    }
-  };
-}
-
-bool ProvenanceAnalysis::relatedSelect(const SelectInst *A, const Value *B) {
-  // If the values are Selects with the same condition, we can do a more precise
-  // check: just check for relations between the values on corresponding arms.
-  if (const SelectInst *SB = dyn_cast<SelectInst>(B))
-    if (A->getCondition() == SB->getCondition())
-      return related(A->getTrueValue(), SB->getTrueValue()) ||
-             related(A->getFalseValue(), SB->getFalseValue());
-
-  // Check both arms of the Select node individually.
-  return related(A->getTrueValue(), B) ||
-         related(A->getFalseValue(), B);
-}
-
-bool ProvenanceAnalysis::relatedPHI(const PHINode *A, const Value *B) {
-  // If the values are PHIs in the same block, we can do a more precise as well
-  // as efficient check: just check for relations between the values on
-  // corresponding edges.
-  if (const PHINode *PNB = dyn_cast<PHINode>(B))
-    if (PNB->getParent() == A->getParent()) {
-      for (unsigned i = 0, e = A->getNumIncomingValues(); i != e; ++i)
-        if (related(A->getIncomingValue(i),
-                    PNB->getIncomingValueForBlock(A->getIncomingBlock(i))))
-          return true;
-      return false;
-    }
-
-  // Check each unique source of the PHI node against B.
-  SmallPtrSet<const Value *, 4> UniqueSrc;
-  for (unsigned i = 0, e = A->getNumIncomingValues(); i != e; ++i) {
-    const Value *PV1 = A->getIncomingValue(i);
-    if (UniqueSrc.insert(PV1) && related(PV1, B))
-      return true;
-  }
-
-  // All of the arms checked out.
-  return false;
-}
-
-/// isStoredObjCPointer - Test if the value of P, or any value covered by its
-/// provenance, is ever stored within the function (not counting callees).
-static bool isStoredObjCPointer(const Value *P) {
-  SmallPtrSet<const Value *, 8> Visited;
-  SmallVector<const Value *, 8> Worklist;
-  Worklist.push_back(P);
-  Visited.insert(P);
-  do {
-    P = Worklist.pop_back_val();
-    for (Value::const_use_iterator UI = P->use_begin(), UE = P->use_end();
-         UI != UE; ++UI) {
-      const User *Ur = *UI;
-      if (isa<StoreInst>(Ur)) {
-        if (UI.getOperandNo() == 0)
-          // The pointer is stored.
-          return true;
-        // The pointed is stored through.
-        continue;
-      }
-      if (isa<CallInst>(Ur))
-        // The pointer is passed as an argument, ignore this.
-        continue;
-      if (isa<PtrToIntInst>(P))
-        // Assume the worst.
-        return true;
-      if (Visited.insert(Ur))
-        Worklist.push_back(Ur);
-    }
-  } while (!Worklist.empty());
-
-  // Everything checked out.
-  return false;
-}
-
-bool ProvenanceAnalysis::relatedCheck(const Value *A, const Value *B) {
-  // Skip past provenance pass-throughs.
-  A = GetUnderlyingObjCPtr(A);
-  B = GetUnderlyingObjCPtr(B);
-
-  // Quick check.
-  if (A == B)
-    return true;
-
-  // Ask regular AliasAnalysis, for a first approximation.
-  switch (AA->alias(A, B)) {
-  case AliasAnalysis::NoAlias:
-    return false;
-  case AliasAnalysis::MustAlias:
-  case AliasAnalysis::PartialAlias:
-    return true;
-  case AliasAnalysis::MayAlias:
-    break;
-  }
-
-  bool AIsIdentified = IsObjCIdentifiedObject(A);
-  bool BIsIdentified = IsObjCIdentifiedObject(B);
-
-  // An ObjC-Identified object can't alias a load if it is never locally stored.
-  if (AIsIdentified) {
-    // Check for an obvious escape.
-    if (isa<LoadInst>(B))
-      return isStoredObjCPointer(A);
-    if (BIsIdentified) {
-      // Check for an obvious escape.
-      if (isa<LoadInst>(A))
-        return isStoredObjCPointer(B);
-      // Both pointers are identified and escapes aren't an evident problem.
-      return false;
-    }
-  } else if (BIsIdentified) {
-    // Check for an obvious escape.
-    if (isa<LoadInst>(A))
-      return isStoredObjCPointer(B);
-  }
-
-   // Special handling for PHI and Select.
-  if (const PHINode *PN = dyn_cast<PHINode>(A))
-    return relatedPHI(PN, B);
-  if (const PHINode *PN = dyn_cast<PHINode>(B))
-    return relatedPHI(PN, A);
-  if (const SelectInst *S = dyn_cast<SelectInst>(A))
-    return relatedSelect(S, B);
-  if (const SelectInst *S = dyn_cast<SelectInst>(B))
-    return relatedSelect(S, A);
-
-  // Conservative.
-  return true;
-}
-
-bool ProvenanceAnalysis::related(const Value *A, const Value *B) {
-  // Begin by inserting a conservative value into the map. If the insertion
-  // fails, we have the answer already. If it succeeds, leave it there until we
-  // compute the real answer to guard against recursive queries.
-  if (A > B) std::swap(A, B);
-  std::pair<CachedResultsTy::iterator, bool> Pair =
-    CachedResults.insert(std::make_pair(ValuePairTy(A, B), true));
-  if (!Pair.second)
-    return Pair.first->second;
-
-  bool Result = relatedCheck(A, B);
-  CachedResults[ValuePairTy(A, B)] = Result;
-  return Result;
-}
-
-namespace {
-  // Sequence - A sequence of states that a pointer may go through in which an
-  // objc_retain and objc_release are actually needed.
-  enum Sequence {
-    S_None,
-    S_Retain,         ///< objc_retain(x)
-    S_CanRelease,     ///< foo(x) -- x could possibly see a ref count decrement
-    S_Use,            ///< any use of x
-    S_Stop,           ///< like S_Release, but code motion is stopped
-    S_Release,        ///< objc_release(x)
-    S_MovableRelease  ///< objc_release(x), !clang.imprecise_release
-  };
-}
-
-static Sequence MergeSeqs(Sequence A, Sequence B, bool TopDown) {
-  // The easy cases.
-  if (A == B)
-    return A;
-  if (A == S_None || B == S_None)
-    return S_None;
-
-  if (A > B) std::swap(A, B);
-  if (TopDown) {
-    // Choose the side which is further along in the sequence.
-    if ((A == S_Retain || A == S_CanRelease) &&
-        (B == S_CanRelease || B == S_Use))
-      return B;
-  } else {
-    // Choose the side which is further along in the sequence.
-    if ((A == S_Use || A == S_CanRelease) &&
-        (B == S_Use || B == S_Release || B == S_Stop || B == S_MovableRelease))
-      return A;
-    // If both sides are releases, choose the more conservative one.
-    if (A == S_Stop && (B == S_Release || B == S_MovableRelease))
-      return A;
-    if (A == S_Release && B == S_MovableRelease)
-      return A;
-  }
-
-  return S_None;
-}
-
-namespace {
-  /// RRInfo - Unidirectional information about either a
-  /// retain-decrement-use-release sequence or release-use-decrement-retain
-  /// reverese sequence.
-  struct RRInfo {
-    /// KnownSafe - After an objc_retain, the reference count of the referenced
-    /// object is known to be positive. Similarly, before an objc_release, the
-    /// reference count of the referenced object is known to be positive. If
-    /// there are retain-release pairs in code regions where the retain count
-    /// is known to be positive, they can be eliminated, regardless of any side
-    /// effects between them.
-    ///
-    /// Also, a retain+release pair nested within another retain+release
-    /// pair all on the known same pointer value can be eliminated, regardless
-    /// of any intervening side effects.
-    ///
-    /// KnownSafe is true when either of these conditions is satisfied.
-    bool KnownSafe;
-
-    /// IsRetainBlock - True if the Calls are objc_retainBlock calls (as
-    /// opposed to objc_retain calls).
-    bool IsRetainBlock;
-
-    /// IsTailCallRelease - True of the objc_release calls are all marked
-    /// with the "tail" keyword.
-    bool IsTailCallRelease;
-
-    /// ReleaseMetadata - If the Calls are objc_release calls and they all have
-    /// a clang.imprecise_release tag, this is the metadata tag.
-    MDNode *ReleaseMetadata;
-
-    /// Calls - For a top-down sequence, the set of objc_retains or
-    /// objc_retainBlocks. For bottom-up, the set of objc_releases.
-    SmallPtrSet<Instruction *, 2> Calls;
-
-    /// ReverseInsertPts - The set of optimal insert positions for
-    /// moving calls in the opposite sequence.
-    SmallPtrSet<Instruction *, 2> ReverseInsertPts;
-
-    RRInfo() :
-      KnownSafe(false), IsRetainBlock(false),
-      IsTailCallRelease(false),
-      ReleaseMetadata(0) {}
-
-    void clear();
-  };
-}
-
-void RRInfo::clear() {
-  KnownSafe = false;
-  IsRetainBlock = false;
-  IsTailCallRelease = false;
-  ReleaseMetadata = 0;
-  Calls.clear();
-  ReverseInsertPts.clear();
-}
-
-namespace {
-  /// PtrState - This class summarizes several per-pointer runtime properties
-  /// which are propogated through the flow graph.
-  class PtrState {
-    /// KnownPositiveRefCount - True if the reference count is known to
-    /// be incremented.
-    bool KnownPositiveRefCount;
-
-    /// Partial - True of we've seen an opportunity for partial RR elimination,
-    /// such as pushing calls into a CFG triangle or into one side of a
-    /// CFG diamond.
-    bool Partial;
-
-    /// Seq - The current position in the sequence.
-    Sequence Seq : 8;
-
-  public:
-    /// RRI - Unidirectional information about the current sequence.
-    /// TODO: Encapsulate this better.
-    RRInfo RRI;
-
-    PtrState() : KnownPositiveRefCount(false), Partial(false),
-                 Seq(S_None) {}
-
-    void SetKnownPositiveRefCount() {
-      KnownPositiveRefCount = true;
-    }
-
-    void ClearRefCount() {
-      KnownPositiveRefCount = false;
-    }
-
-    bool IsKnownIncremented() const {
-      return KnownPositiveRefCount;
-    }
-
-    void SetSeq(Sequence NewSeq) {
-      Seq = NewSeq;
-    }
-
-    Sequence GetSeq() const {
-      return Seq;
-    }
-
-    void ClearSequenceProgress() {
-      ResetSequenceProgress(S_None);
-    }
-
-    void ResetSequenceProgress(Sequence NewSeq) {
-      Seq = NewSeq;
-      Partial = false;
-      RRI.clear();
-    }
-
-    void Merge(const PtrState &Other, bool TopDown);
-  };
-}
-
-void
-PtrState::Merge(const PtrState &Other, bool TopDown) {
-  Seq = MergeSeqs(Seq, Other.Seq, TopDown);
-  KnownPositiveRefCount = KnownPositiveRefCount && Other.KnownPositiveRefCount;
-
-  // We can't merge a plain objc_retain with an objc_retainBlock.
-  if (RRI.IsRetainBlock != Other.RRI.IsRetainBlock)
-    Seq = S_None;
-
-  // If we're not in a sequence (anymore), drop all associated state.
-  if (Seq == S_None) {
-    Partial = false;
-    RRI.clear();
-  } else if (Partial || Other.Partial) {
-    // If we're doing a merge on a path that's previously seen a partial
-    // merge, conservatively drop the sequence, to avoid doing partial
-    // RR elimination. If the branch predicates for the two merge differ,
-    // mixing them is unsafe.
-    ClearSequenceProgress();
-  } else {
-    // Conservatively merge the ReleaseMetadata information.
-    if (RRI.ReleaseMetadata != Other.RRI.ReleaseMetadata)
-      RRI.ReleaseMetadata = 0;
-
-    RRI.KnownSafe = RRI.KnownSafe && Other.RRI.KnownSafe;
-    RRI.IsTailCallRelease = RRI.IsTailCallRelease &&
-                            Other.RRI.IsTailCallRelease;
-    RRI.Calls.insert(Other.RRI.Calls.begin(), Other.RRI.Calls.end());
-
-    // Merge the insert point sets. If there are any differences,
-    // that makes this a partial merge.
-    Partial = RRI.ReverseInsertPts.size() != Other.RRI.ReverseInsertPts.size();
-    for (SmallPtrSet<Instruction *, 2>::const_iterator
-         I = Other.RRI.ReverseInsertPts.begin(),
-         E = Other.RRI.ReverseInsertPts.end(); I != E; ++I)
-      Partial |= RRI.ReverseInsertPts.insert(*I);
-  }
-}
-
-namespace {
-  /// BBState - Per-BasicBlock state.
-  class BBState {
-    /// TopDownPathCount - The number of unique control paths from the entry
-    /// which can reach this block.
-    unsigned TopDownPathCount;
-
-    /// BottomUpPathCount - The number of unique control paths to exits
-    /// from this block.
-    unsigned BottomUpPathCount;
-
-    /// MapTy - A type for PerPtrTopDown and PerPtrBottomUp.
-    typedef MapVector<const Value *, PtrState> MapTy;
-
-    /// PerPtrTopDown - The top-down traversal uses this to record information
-    /// known about a pointer at the bottom of each block.
-    MapTy PerPtrTopDown;
-
-    /// PerPtrBottomUp - The bottom-up traversal uses this to record information
-    /// known about a pointer at the top of each block.
-    MapTy PerPtrBottomUp;
-
-    /// Preds, Succs - Effective successors and predecessors of the current
-    /// block (this ignores ignorable edges and ignored backedges).
-    SmallVector<BasicBlock *, 2> Preds;
-    SmallVector<BasicBlock *, 2> Succs;
-
-  public:
-    BBState() : TopDownPathCount(0), BottomUpPathCount(0) {}
-
-    typedef MapTy::iterator ptr_iterator;
-    typedef MapTy::const_iterator ptr_const_iterator;
-
-    ptr_iterator top_down_ptr_begin() { return PerPtrTopDown.begin(); }
-    ptr_iterator top_down_ptr_end() { return PerPtrTopDown.end(); }
-    ptr_const_iterator top_down_ptr_begin() const {
-      return PerPtrTopDown.begin();
-    }
-    ptr_const_iterator top_down_ptr_end() const {
-      return PerPtrTopDown.end();
-    }
-
-    ptr_iterator bottom_up_ptr_begin() { return PerPtrBottomUp.begin(); }
-    ptr_iterator bottom_up_ptr_end() { return PerPtrBottomUp.end(); }
-    ptr_const_iterator bottom_up_ptr_begin() const {
-      return PerPtrBottomUp.begin();
-    }
-    ptr_const_iterator bottom_up_ptr_end() const {
-      return PerPtrBottomUp.end();
-    }
-
-    /// SetAsEntry - Mark this block as being an entry block, which has one
-    /// path from the entry by definition.
-    void SetAsEntry() { TopDownPathCount = 1; }
-
-    /// SetAsExit - Mark this block as being an exit block, which has one
-    /// path to an exit by definition.
-    void SetAsExit()  { BottomUpPathCount = 1; }
-
-    PtrState &getPtrTopDownState(const Value *Arg) {
-      return PerPtrTopDown[Arg];
-    }
-
-    PtrState &getPtrBottomUpState(const Value *Arg) {
-      return PerPtrBottomUp[Arg];
-    }
-
-    void clearBottomUpPointers() {
-      PerPtrBottomUp.clear();
-    }
-
-    void clearTopDownPointers() {
-      PerPtrTopDown.clear();
-    }
-
-    void InitFromPred(const BBState &Other);
-    void InitFromSucc(const BBState &Other);
-    void MergePred(const BBState &Other);
-    void MergeSucc(const BBState &Other);
-
-    /// GetAllPathCount - Return the number of possible unique paths from an
-    /// entry to an exit which pass through this block. This is only valid
-    /// after both the top-down and bottom-up traversals are complete.
-    unsigned GetAllPathCount() const {
-      assert(TopDownPathCount != 0);
-      assert(BottomUpPathCount != 0);
-      return TopDownPathCount * BottomUpPathCount;
-    }
-
-    // Specialized CFG utilities.
-    typedef SmallVectorImpl<BasicBlock *>::const_iterator edge_iterator;
-    edge_iterator pred_begin() { return Preds.begin(); }
-    edge_iterator pred_end() { return Preds.end(); }
-    edge_iterator succ_begin() { return Succs.begin(); }
-    edge_iterator succ_end() { return Succs.end(); }
-
-    void addSucc(BasicBlock *Succ) { Succs.push_back(Succ); }
-    void addPred(BasicBlock *Pred) { Preds.push_back(Pred); }
-
-    bool isExit() const { return Succs.empty(); }
-  };
-}
-
-void BBState::InitFromPred(const BBState &Other) {
-  PerPtrTopDown = Other.PerPtrTopDown;
-  TopDownPathCount = Other.TopDownPathCount;
-}
-
-void BBState::InitFromSucc(const BBState &Other) {
-  PerPtrBottomUp = Other.PerPtrBottomUp;
-  BottomUpPathCount = Other.BottomUpPathCount;
-}
-
-/// MergePred - The top-down traversal uses this to merge information about
-/// predecessors to form the initial state for a new block.
-void BBState::MergePred(const BBState &Other) {
-  // Other.TopDownPathCount can be 0, in which case it is either dead or a
-  // loop backedge. Loop backedges are special.
-  TopDownPathCount += Other.TopDownPathCount;
-
-  // Check for overflow. If we have overflow, fall back to conservative behavior.
-  if (TopDownPathCount < Other.TopDownPathCount) {
-    clearTopDownPointers();
-    return;
-  }
-
-  // For each entry in the other set, if our set has an entry with the same key,
-  // merge the entries. Otherwise, copy the entry and merge it with an empty
-  // entry.
-  for (ptr_const_iterator MI = Other.top_down_ptr_begin(),
-       ME = Other.top_down_ptr_end(); MI != ME; ++MI) {
-    std::pair<ptr_iterator, bool> Pair = PerPtrTopDown.insert(*MI);
-    Pair.first->second.Merge(Pair.second ? PtrState() : MI->second,
-                             /*TopDown=*/true);
-  }
-
-  // For each entry in our set, if the other set doesn't have an entry with the
-  // same key, force it to merge with an empty entry.
-  for (ptr_iterator MI = top_down_ptr_begin(),
-       ME = top_down_ptr_end(); MI != ME; ++MI)
-    if (Other.PerPtrTopDown.find(MI->first) == Other.PerPtrTopDown.end())
-      MI->second.Merge(PtrState(), /*TopDown=*/true);
-}
-
-/// MergeSucc - The bottom-up traversal uses this to merge information about
-/// successors to form the initial state for a new block.
-void BBState::MergeSucc(const BBState &Other) {
-  // Other.BottomUpPathCount can be 0, in which case it is either dead or a
-  // loop backedge. Loop backedges are special.
-  BottomUpPathCount += Other.BottomUpPathCount;
-
-  // Check for overflow. If we have overflow, fall back to conservative behavior.
-  if (BottomUpPathCount < Other.BottomUpPathCount) {
-    clearBottomUpPointers();
-    return;
-  }
-
-  // For each entry in the other set, if our set has an entry with the
-  // same key, merge the entries. Otherwise, copy the entry and merge
-  // it with an empty entry.
-  for (ptr_const_iterator MI = Other.bottom_up_ptr_begin(),
-       ME = Other.bottom_up_ptr_end(); MI != ME; ++MI) {
-    std::pair<ptr_iterator, bool> Pair = PerPtrBottomUp.insert(*MI);
-    Pair.first->second.Merge(Pair.second ? PtrState() : MI->second,
-                             /*TopDown=*/false);
-  }
-
-  // For each entry in our set, if the other set doesn't have an entry
-  // with the same key, force it to merge with an empty entry.
-  for (ptr_iterator MI = bottom_up_ptr_begin(),
-       ME = bottom_up_ptr_end(); MI != ME; ++MI)
-    if (Other.PerPtrBottomUp.find(MI->first) == Other.PerPtrBottomUp.end())
-      MI->second.Merge(PtrState(), /*TopDown=*/false);
-}
-
-namespace {
-  /// ObjCARCOpt - The main ARC optimization pass.
-  class ObjCARCOpt : public FunctionPass {
-    bool Changed;
-    ProvenanceAnalysis PA;
-
-    /// Run - A flag indicating whether this optimization pass should run.
-    bool Run;
-
-    /// RetainRVCallee, etc. - Declarations for ObjC runtime
-    /// functions, for use in creating calls to them. These are initialized
-    /// lazily to avoid cluttering up the Module with unused declarations.
-    Constant *RetainRVCallee, *AutoreleaseRVCallee, *ReleaseCallee,
-             *RetainCallee, *RetainBlockCallee, *AutoreleaseCallee;
-
-    /// UsedInThisFunciton - Flags which determine whether each of the
-    /// interesting runtine functions is in fact used in the current function.
-    unsigned UsedInThisFunction;
-
-    /// ImpreciseReleaseMDKind - The Metadata Kind for clang.imprecise_release
-    /// metadata.
-    unsigned ImpreciseReleaseMDKind;
-
-    /// CopyOnEscapeMDKind - The Metadata Kind for clang.arc.copy_on_escape
-    /// metadata.
-    unsigned CopyOnEscapeMDKind;
-
-    /// NoObjCARCExceptionsMDKind - The Metadata Kind for
-    /// clang.arc.no_objc_arc_exceptions metadata.
-    unsigned NoObjCARCExceptionsMDKind;
-
-    Constant *getRetainRVCallee(Module *M);
-    Constant *getAutoreleaseRVCallee(Module *M);
-    Constant *getReleaseCallee(Module *M);
-    Constant *getRetainCallee(Module *M);
-    Constant *getRetainBlockCallee(Module *M);
-    Constant *getAutoreleaseCallee(Module *M);
-
-    bool IsRetainBlockOptimizable(const Instruction *Inst);
-
-    void OptimizeRetainCall(Function &F, Instruction *Retain);
-    bool OptimizeRetainRVCall(Function &F, Instruction *RetainRV);
-    void OptimizeAutoreleaseRVCall(Function &F, Instruction *AutoreleaseRV);
-    void OptimizeIndividualCalls(Function &F);
-
-    void CheckForCFGHazards(const BasicBlock *BB,
-                            DenseMap<const BasicBlock *, BBState> &BBStates,
-                            BBState &MyStates) const;
-    bool VisitInstructionBottomUp(Instruction *Inst,
-                                  BasicBlock *BB,
-                                  MapVector<Value *, RRInfo> &Retains,
-                                  BBState &MyStates);
-    bool VisitBottomUp(BasicBlock *BB,
-                       DenseMap<const BasicBlock *, BBState> &BBStates,
-                       MapVector<Value *, RRInfo> &Retains);
-    bool VisitInstructionTopDown(Instruction *Inst,
-                                 DenseMap<Value *, RRInfo> &Releases,
-                                 BBState &MyStates);
-    bool VisitTopDown(BasicBlock *BB,
-                      DenseMap<const BasicBlock *, BBState> &BBStates,
-                      DenseMap<Value *, RRInfo> &Releases);
-    bool Visit(Function &F,
-               DenseMap<const BasicBlock *, BBState> &BBStates,
-               MapVector<Value *, RRInfo> &Retains,
-               DenseMap<Value *, RRInfo> &Releases);
-
-    void MoveCalls(Value *Arg, RRInfo &RetainsToMove, RRInfo &ReleasesToMove,
-                   MapVector<Value *, RRInfo> &Retains,
-                   DenseMap<Value *, RRInfo> &Releases,
-                   SmallVectorImpl<Instruction *> &DeadInsts,
-                   Module *M);
-
-    bool PerformCodePlacement(DenseMap<const BasicBlock *, BBState> &BBStates,
-                              MapVector<Value *, RRInfo> &Retains,
-                              DenseMap<Value *, RRInfo> &Releases,
-                              Module *M);
-
-    void OptimizeWeakCalls(Function &F);
-
-    bool OptimizeSequences(Function &F);
-
-    void OptimizeReturns(Function &F);
-
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
-    virtual bool doInitialization(Module &M);
-    virtual bool runOnFunction(Function &F);
-    virtual void releaseMemory();
-
-  public:
-    static char ID;
-    ObjCARCOpt() : FunctionPass(ID) {
-      initializeObjCARCOptPass(*PassRegistry::getPassRegistry());
-    }
-  };
-}
-
-char ObjCARCOpt::ID = 0;
-INITIALIZE_PASS_BEGIN(ObjCARCOpt,
-                      "objc-arc", "ObjC ARC optimization", false, false)
-INITIALIZE_PASS_DEPENDENCY(ObjCARCAliasAnalysis)
-INITIALIZE_PASS_END(ObjCARCOpt,
-                    "objc-arc", "ObjC ARC optimization", false, false)
-
-Pass *llvm::createObjCARCOptPass() {
-  return new ObjCARCOpt();
-}
-
-void ObjCARCOpt::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.addRequired<ObjCARCAliasAnalysis>();
-  AU.addRequired<AliasAnalysis>();
-  // ARC optimization doesn't currently split critical edges.
-  AU.setPreservesCFG();
-}
-
-bool ObjCARCOpt::IsRetainBlockOptimizable(const Instruction *Inst) {
-  // Without the magic metadata tag, we have to assume this might be an
-  // objc_retainBlock call inserted to convert a block pointer to an id,
-  // in which case it really is needed.
-  if (!Inst->getMetadata(CopyOnEscapeMDKind))
-    return false;
-
-  // If the pointer "escapes" (not including being used in a call),
-  // the copy may be needed.
-  if (DoesObjCBlockEscape(Inst))
-    return false;
-
-  // Otherwise, it's not needed.
-  return true;
-}
-
-Constant *ObjCARCOpt::getRetainRVCallee(Module *M) {
-  if (!RetainRVCallee) {
-    LLVMContext &C = M->getContext();
-    Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-    Type *Params[] = { I8X };
-    FunctionType *FTy = FunctionType::get(I8X, Params, /*isVarArg=*/false);
-    AttributeSet Attribute =
-      AttributeSet().addAttr(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::get(C, Attribute::NoUnwind));
-    RetainRVCallee =
-      M->getOrInsertFunction("objc_retainAutoreleasedReturnValue", FTy,
-                             Attribute);
-  }
-  return RetainRVCallee;
-}
-
-Constant *ObjCARCOpt::getAutoreleaseRVCallee(Module *M) {
-  if (!AutoreleaseRVCallee) {
-    LLVMContext &C = M->getContext();
-    Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-    Type *Params[] = { I8X };
-    FunctionType *FTy = FunctionType::get(I8X, Params, /*isVarArg=*/false);
-    AttributeSet Attribute =
-      AttributeSet().addAttr(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::get(C, Attribute::NoUnwind));
-    AutoreleaseRVCallee =
-      M->getOrInsertFunction("objc_autoreleaseReturnValue", FTy,
-                             Attribute);
-  }
-  return AutoreleaseRVCallee;
-}
-
-Constant *ObjCARCOpt::getReleaseCallee(Module *M) {
-  if (!ReleaseCallee) {
-    LLVMContext &C = M->getContext();
-    Type *Params[] = { PointerType::getUnqual(Type::getInt8Ty(C)) };
-    AttributeSet Attribute =
-      AttributeSet().addAttr(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::get(C, Attribute::NoUnwind));
-    ReleaseCallee =
-      M->getOrInsertFunction(
-        "objc_release",
-        FunctionType::get(Type::getVoidTy(C), Params, /*isVarArg=*/false),
-        Attribute);
-  }
-  return ReleaseCallee;
-}
-
-Constant *ObjCARCOpt::getRetainCallee(Module *M) {
-  if (!RetainCallee) {
-    LLVMContext &C = M->getContext();
-    Type *Params[] = { PointerType::getUnqual(Type::getInt8Ty(C)) };
-    AttributeSet Attribute =
-      AttributeSet().addAttr(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::get(C, Attribute::NoUnwind));
-    RetainCallee =
-      M->getOrInsertFunction(
-        "objc_retain",
-        FunctionType::get(Params[0], Params, /*isVarArg=*/false),
-        Attribute);
-  }
-  return RetainCallee;
-}
-
-Constant *ObjCARCOpt::getRetainBlockCallee(Module *M) {
-  if (!RetainBlockCallee) {
-    LLVMContext &C = M->getContext();
-    Type *Params[] = { PointerType::getUnqual(Type::getInt8Ty(C)) };
-    // objc_retainBlock is not nounwind because it calls user copy constructors
-    // which could theoretically throw.
-    RetainBlockCallee =
-      M->getOrInsertFunction(
-        "objc_retainBlock",
-        FunctionType::get(Params[0], Params, /*isVarArg=*/false),
-        AttributeSet());
-  }
-  return RetainBlockCallee;
-}
-
-Constant *ObjCARCOpt::getAutoreleaseCallee(Module *M) {
-  if (!AutoreleaseCallee) {
-    LLVMContext &C = M->getContext();
-    Type *Params[] = { PointerType::getUnqual(Type::getInt8Ty(C)) };
-    AttributeSet Attribute =
-      AttributeSet().addAttr(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::get(C, Attribute::NoUnwind));
-    AutoreleaseCallee =
-      M->getOrInsertFunction(
-        "objc_autorelease",
-        FunctionType::get(Params[0], Params, /*isVarArg=*/false),
-        Attribute);
-  }
-  return AutoreleaseCallee;
-}
-
-/// IsPotentialUse - Test whether the given value is possible a
-/// reference-counted pointer, including tests which utilize AliasAnalysis.
-static bool IsPotentialUse(const Value *Op, AliasAnalysis &AA) {
-  // First make the rudimentary check.
-  if (!IsPotentialUse(Op))
-    return false;
-
-  // Objects in constant memory are not reference-counted.
-  if (AA.pointsToConstantMemory(Op))
-    return false;
-
-  // Pointers in constant memory are not pointing to reference-counted objects.
-  if (const LoadInst *LI = dyn_cast<LoadInst>(Op))
-    if (AA.pointsToConstantMemory(LI->getPointerOperand()))
-      return false;
-
-  // Otherwise assume the worst.
-  return true;
-}
-
-/// CanAlterRefCount - Test whether the given instruction can result in a
-/// reference count modification (positive or negative) for the pointer's
-/// object.
-static bool
-CanAlterRefCount(const Instruction *Inst, const Value *Ptr,
-                 ProvenanceAnalysis &PA, InstructionClass Class) {
-  switch (Class) {
-  case IC_Autorelease:
-  case IC_AutoreleaseRV:
-  case IC_User:
-    // These operations never directly modify a reference count.
-    return false;
-  default: break;
-  }
-
-  ImmutableCallSite CS = static_cast<const Value *>(Inst);
-  assert(CS && "Only calls can alter reference counts!");
-
-  // See if AliasAnalysis can help us with the call.
-  AliasAnalysis::ModRefBehavior MRB = PA.getAA()->getModRefBehavior(CS);
-  if (AliasAnalysis::onlyReadsMemory(MRB))
-    return false;
-  if (AliasAnalysis::onlyAccessesArgPointees(MRB)) {
-    for (ImmutableCallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end();
-         I != E; ++I) {
-      const Value *Op = *I;
-      if (IsPotentialUse(Op, *PA.getAA()) && PA.related(Ptr, Op))
-        return true;
-    }
-    return false;
-  }
-
-  // Assume the worst.
-  return true;
-}
-
-/// CanUse - Test whether the given instruction can "use" the given pointer's
-/// object in a way that requires the reference count to be positive.
-static bool
-CanUse(const Instruction *Inst, const Value *Ptr, ProvenanceAnalysis &PA,
-       InstructionClass Class) {
-  // IC_Call operations (as opposed to IC_CallOrUser) never "use" objc pointers.
-  if (Class == IC_Call)
-    return false;
-
-  // Consider various instructions which may have pointer arguments which are
-  // not "uses".
-  if (const ICmpInst *ICI = dyn_cast<ICmpInst>(Inst)) {
-    // Comparing a pointer with null, or any other constant, isn't really a use,
-    // because we don't care what the pointer points to, or about the values
-    // of any other dynamic reference-counted pointers.
-    if (!IsPotentialUse(ICI->getOperand(1), *PA.getAA()))
-      return false;
-  } else if (ImmutableCallSite CS = static_cast<const Value *>(Inst)) {
-    // For calls, just check the arguments (and not the callee operand).
-    for (ImmutableCallSite::arg_iterator OI = CS.arg_begin(),
-         OE = CS.arg_end(); OI != OE; ++OI) {
-      const Value *Op = *OI;
-      if (IsPotentialUse(Op, *PA.getAA()) && PA.related(Ptr, Op))
-        return true;
-    }
-    return false;
-  } else if (const StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
-    // Special-case stores, because we don't care about the stored value, just
-    // the store address.
-    const Value *Op = GetUnderlyingObjCPtr(SI->getPointerOperand());
-    // If we can't tell what the underlying object was, assume there is a
-    // dependence.
-    return IsPotentialUse(Op, *PA.getAA()) && PA.related(Op, Ptr);
-  }
-
-  // Check each operand for a match.
-  for (User::const_op_iterator OI = Inst->op_begin(), OE = Inst->op_end();
-       OI != OE; ++OI) {
-    const Value *Op = *OI;
-    if (IsPotentialUse(Op, *PA.getAA()) && PA.related(Ptr, Op))
-      return true;
-  }
-  return false;
-}
-
-/// CanInterruptRV - Test whether the given instruction can autorelease
-/// any pointer or cause an autoreleasepool pop.
-static bool
-CanInterruptRV(InstructionClass Class) {
-  switch (Class) {
-  case IC_AutoreleasepoolPop:
-  case IC_CallOrUser:
-  case IC_Call:
-  case IC_Autorelease:
-  case IC_AutoreleaseRV:
-  case IC_FusedRetainAutorelease:
-  case IC_FusedRetainAutoreleaseRV:
-    return true;
-  default:
-    return false;
-  }
-}
-
-namespace {
-  /// DependenceKind - There are several kinds of dependence-like concepts in
-  /// use here.
-  enum DependenceKind {
-    NeedsPositiveRetainCount,
-    AutoreleasePoolBoundary,
-    CanChangeRetainCount,
-    RetainAutoreleaseDep,       ///< Blocks objc_retainAutorelease.
-    RetainAutoreleaseRVDep,     ///< Blocks objc_retainAutoreleaseReturnValue.
-    RetainRVDep                 ///< Blocks objc_retainAutoreleasedReturnValue.
-  };
-}
-
-/// Depends - Test if there can be dependencies on Inst through Arg. This
-/// function only tests dependencies relevant for removing pairs of calls.
-static bool
-Depends(DependenceKind Flavor, Instruction *Inst, const Value *Arg,
-        ProvenanceAnalysis &PA) {
-  // If we've reached the definition of Arg, stop.
-  if (Inst == Arg)
-    return true;
-
-  switch (Flavor) {
-  case NeedsPositiveRetainCount: {
-    InstructionClass Class = GetInstructionClass(Inst);
-    switch (Class) {
-    case IC_AutoreleasepoolPop:
-    case IC_AutoreleasepoolPush:
-    case IC_None:
-      return false;
-    default:
-      return CanUse(Inst, Arg, PA, Class);
-    }
-  }
-
-  case AutoreleasePoolBoundary: {
-    InstructionClass Class = GetInstructionClass(Inst);
-    switch (Class) {
-    case IC_AutoreleasepoolPop:
-    case IC_AutoreleasepoolPush:
-      // These mark the end and begin of an autorelease pool scope.
-      return true;
-    default:
-      // Nothing else does this.
-      return false;
-    }
-  }
-
-  case CanChangeRetainCount: {
-    InstructionClass Class = GetInstructionClass(Inst);
-    switch (Class) {
-    case IC_AutoreleasepoolPop:
-      // Conservatively assume this can decrement any count.
-      return true;
-    case IC_AutoreleasepoolPush:
-    case IC_None:
-      return false;
-    default:
-      return CanAlterRefCount(Inst, Arg, PA, Class);
-    }
-  }
-
-  case RetainAutoreleaseDep:
-    switch (GetBasicInstructionClass(Inst)) {
-    case IC_AutoreleasepoolPop:
-    case IC_AutoreleasepoolPush:
-      // Don't merge an objc_autorelease with an objc_retain inside a different
-      // autoreleasepool scope.
-      return true;
-    case IC_Retain:
-    case IC_RetainRV:
-      // Check for a retain of the same pointer for merging.
-      return GetObjCArg(Inst) == Arg;
-    default:
-      // Nothing else matters for objc_retainAutorelease formation.
-      return false;
-    }
-
-  case RetainAutoreleaseRVDep: {
-    InstructionClass Class = GetBasicInstructionClass(Inst);
-    switch (Class) {
-    case IC_Retain:
-    case IC_RetainRV:
-      // Check for a retain of the same pointer for merging.
-      return GetObjCArg(Inst) == Arg;
-    default:
-      // Anything that can autorelease interrupts
-      // retainAutoreleaseReturnValue formation.
-      return CanInterruptRV(Class);
-    }
-  }
-
-  case RetainRVDep:
-    return CanInterruptRV(GetBasicInstructionClass(Inst));
-  }
-
-  llvm_unreachable("Invalid dependence flavor");
-}
-
-/// FindDependencies - Walk up the CFG from StartPos (which is in StartBB) and
-/// find local and non-local dependencies on Arg.
-/// TODO: Cache results?
-static void
-FindDependencies(DependenceKind Flavor,
-                 const Value *Arg,
-                 BasicBlock *StartBB, Instruction *StartInst,
-                 SmallPtrSet<Instruction *, 4> &DependingInstructions,
-                 SmallPtrSet<const BasicBlock *, 4> &Visited,
-                 ProvenanceAnalysis &PA) {
-  BasicBlock::iterator StartPos = StartInst;
-
-  SmallVector<std::pair<BasicBlock *, BasicBlock::iterator>, 4> Worklist;
-  Worklist.push_back(std::make_pair(StartBB, StartPos));
-  do {
-    std::pair<BasicBlock *, BasicBlock::iterator> Pair =
-      Worklist.pop_back_val();
-    BasicBlock *LocalStartBB = Pair.first;
-    BasicBlock::iterator LocalStartPos = Pair.second;
-    BasicBlock::iterator StartBBBegin = LocalStartBB->begin();
-    for (;;) {
-      if (LocalStartPos == StartBBBegin) {
-        pred_iterator PI(LocalStartBB), PE(LocalStartBB, false);
-        if (PI == PE)
-          // If we've reached the function entry, produce a null dependence.
-          DependingInstructions.insert(0);
-        else
-          // Add the predecessors to the worklist.
-          do {
-            BasicBlock *PredBB = *PI;
-            if (Visited.insert(PredBB))
-              Worklist.push_back(std::make_pair(PredBB, PredBB->end()));
-          } while (++PI != PE);
-        break;
-      }
-
-      Instruction *Inst = --LocalStartPos;
-      if (Depends(Flavor, Inst, Arg, PA)) {
-        DependingInstructions.insert(Inst);
-        break;
-      }
-    }
-  } while (!Worklist.empty());
-
-  // Determine whether the original StartBB post-dominates all of the blocks we
-  // visited. If not, insert a sentinal indicating that most optimizations are
-  // not safe.
-  for (SmallPtrSet<const BasicBlock *, 4>::const_iterator I = Visited.begin(),
-       E = Visited.end(); I != E; ++I) {
-    const BasicBlock *BB = *I;
-    if (BB == StartBB)
-      continue;
-    const TerminatorInst *TI = cast<TerminatorInst>(&BB->back());
-    for (succ_const_iterator SI(TI), SE(TI, false); SI != SE; ++SI) {
-      const BasicBlock *Succ = *SI;
-      if (Succ != StartBB && !Visited.count(Succ)) {
-        DependingInstructions.insert(reinterpret_cast<Instruction *>(-1));
-        return;
-      }
-    }
-  }
-}
-
-static bool isNullOrUndef(const Value *V) {
-  return isa<ConstantPointerNull>(V) || isa<UndefValue>(V);
-}
-
-static bool isNoopInstruction(const Instruction *I) {
-  return isa<BitCastInst>(I) ||
-         (isa<GetElementPtrInst>(I) &&
-          cast<GetElementPtrInst>(I)->hasAllZeroIndices());
-}
-
-/// OptimizeRetainCall - Turn objc_retain into
-/// objc_retainAutoreleasedReturnValue if the operand is a return value.
-void
-ObjCARCOpt::OptimizeRetainCall(Function &F, Instruction *Retain) {
-  ImmutableCallSite CS(GetObjCArg(Retain));
-  const Instruction *Call = CS.getInstruction();
-  if (!Call) return;
-  if (Call->getParent() != Retain->getParent()) return;
-
-  // Check that the call is next to the retain.
-  BasicBlock::const_iterator I = Call;
-  ++I;
-  while (isNoopInstruction(I)) ++I;
-  if (&*I != Retain)
-    return;
-
-  // Turn it to an objc_retainAutoreleasedReturnValue..
-  Changed = true;
-  ++NumPeeps;
-
-  DEBUG(dbgs() << "ObjCARCOpt::OptimizeRetainCall: Transforming "
-                  "objc_retainAutoreleasedReturnValue => "
-                  "objc_retain since the operand is not a return value.\n"
-                  "                                Old: "
-               << *Retain << "\n");
-
-  cast<CallInst>(Retain)->setCalledFunction(getRetainRVCallee(F.getParent()));
-
-  DEBUG(dbgs() << "                                New: "
-               << *Retain << "\n");
-}
-
-/// OptimizeRetainRVCall - Turn objc_retainAutoreleasedReturnValue into
-/// objc_retain if the operand is not a return value.  Or, if it can be paired
-/// with an objc_autoreleaseReturnValue, delete the pair and return true.
-bool
-ObjCARCOpt::OptimizeRetainRVCall(Function &F, Instruction *RetainRV) {
-  // Check for the argument being from an immediately preceding call or invoke.
-  const Value *Arg = GetObjCArg(RetainRV);
-  ImmutableCallSite CS(Arg);
-  if (const Instruction *Call = CS.getInstruction()) {
-    if (Call->getParent() == RetainRV->getParent()) {
-      BasicBlock::const_iterator I = Call;
-      ++I;
-      while (isNoopInstruction(I)) ++I;
-      if (&*I == RetainRV)
-        return false;
-    } else if (const InvokeInst *II = dyn_cast<InvokeInst>(Call)) {
-      BasicBlock *RetainRVParent = RetainRV->getParent();
-      if (II->getNormalDest() == RetainRVParent) {
-        BasicBlock::const_iterator I = RetainRVParent->begin();
-        while (isNoopInstruction(I)) ++I;
-        if (&*I == RetainRV)
-          return false;
-      }
-    }
-  }
-
-  // Check for being preceded by an objc_autoreleaseReturnValue on the same
-  // pointer. In this case, we can delete the pair.
-  BasicBlock::iterator I = RetainRV, Begin = RetainRV->getParent()->begin();
-  if (I != Begin) {
-    do --I; while (I != Begin && isNoopInstruction(I));
-    if (GetBasicInstructionClass(I) == IC_AutoreleaseRV &&
-        GetObjCArg(I) == Arg) {
-      Changed = true;
-      ++NumPeeps;
-
-      DEBUG(dbgs() << "ObjCARCOpt::OptimizeRetainRVCall: Erasing " << *I << "\n"
-                   << "                                  Erasing " << *RetainRV
-                   << "\n");
-
-      EraseInstruction(I);
-      EraseInstruction(RetainRV);
-      return true;
-    }
-  }
-
-  // Turn it to a plain objc_retain.
-  Changed = true;
-  ++NumPeeps;
-
-  DEBUG(dbgs() << "ObjCARCOpt::OptimizeRetainRVCall: Transforming "
-                  "objc_retainAutoreleasedReturnValue => "
-                  "objc_retain since the operand is not a return value.\n"
-                  "                                  Old: "
-               << *RetainRV << "\n");
-
-  cast<CallInst>(RetainRV)->setCalledFunction(getRetainCallee(F.getParent()));
-
-  DEBUG(dbgs() << "                                  New: "
-               << *RetainRV << "\n");
-
-  return false;
-}
-
-/// OptimizeAutoreleaseRVCall - Turn objc_autoreleaseReturnValue into
-/// objc_autorelease if the result is not used as a return value.
-void
-ObjCARCOpt::OptimizeAutoreleaseRVCall(Function &F, Instruction *AutoreleaseRV) {
-  // Check for a return of the pointer value.
-  const Value *Ptr = GetObjCArg(AutoreleaseRV);
-  SmallVector<const Value *, 2> Users;
-  Users.push_back(Ptr);
-  do {
-    Ptr = Users.pop_back_val();
-    for (Value::const_use_iterator UI = Ptr->use_begin(), UE = Ptr->use_end();
-         UI != UE; ++UI) {
-      const User *I = *UI;
-      if (isa<ReturnInst>(I) || GetBasicInstructionClass(I) == IC_RetainRV)
-        return;
-      if (isa<BitCastInst>(I))
-        Users.push_back(I);
-    }
-  } while (!Users.empty());
-
-  Changed = true;
-  ++NumPeeps;
-
-  DEBUG(dbgs() << "ObjCARCOpt::OptimizeAutoreleaseRVCall: Transforming "
-                  "objc_autoreleaseReturnValue => "
-                  "objc_autorelease since its operand is not used as a return "
-                  "value.\n"
-                  "                                       Old: "
-               << *AutoreleaseRV << "\n");
-
-  cast<CallInst>(AutoreleaseRV)->
-    setCalledFunction(getAutoreleaseCallee(F.getParent()));
-
-  DEBUG(dbgs() << "                                       New: "
-               << *AutoreleaseRV << "\n");
-
-}
-
-/// OptimizeIndividualCalls - Visit each call, one at a time, and make
-/// simplifications without doing any additional analysis.
-void ObjCARCOpt::OptimizeIndividualCalls(Function &F) {
-  // Reset all the flags in preparation for recomputing them.
-  UsedInThisFunction = 0;
-
-  // Visit all objc_* calls in F.
-  for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
-    Instruction *Inst = &*I++;
-
-    DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Visiting: " <<
-          *Inst << "\n");
-
-    InstructionClass Class = GetBasicInstructionClass(Inst);
-
-    switch (Class) {
-    default: break;
-
-    // Delete no-op casts. These function calls have special semantics, but
-    // the semantics are entirely implemented via lowering in the front-end,
-    // so by the time they reach the optimizer, they are just no-op calls
-    // which return their argument.
-    //
-    // There are gray areas here, as the ability to cast reference-counted
-    // pointers to raw void* and back allows code to break ARC assumptions,
-    // however these are currently considered to be unimportant.
-    case IC_NoopCast:
-      Changed = true;
-      ++NumNoops;
-      DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Erasing no-op cast:"
-                   " " << *Inst << "\n");
-      EraseInstruction(Inst);
-      continue;
-
-    // If the pointer-to-weak-pointer is null, it's undefined behavior.
-    case IC_StoreWeak:
-    case IC_LoadWeak:
-    case IC_LoadWeakRetained:
-    case IC_InitWeak:
-    case IC_DestroyWeak: {
-      CallInst *CI = cast<CallInst>(Inst);
-      if (isNullOrUndef(CI->getArgOperand(0))) {
-        Changed = true;
-        Type *Ty = CI->getArgOperand(0)->getType();
-        new StoreInst(UndefValue::get(cast<PointerType>(Ty)->getElementType()),
-                      Constant::getNullValue(Ty),
-                      CI);
-        llvm::Value *NewValue = UndefValue::get(CI->getType());
-        DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: A null "
-                        "pointer-to-weak-pointer is undefined behavior.\n"
-                        "                                     Old = " << *CI <<
-                        "\n                                     New = " <<
-                        *NewValue << "\n");
-        CI->replaceAllUsesWith(NewValue);
-        CI->eraseFromParent();
-        continue;
-      }
-      break;
-    }
-    case IC_CopyWeak:
-    case IC_MoveWeak: {
-      CallInst *CI = cast<CallInst>(Inst);
-      if (isNullOrUndef(CI->getArgOperand(0)) ||
-          isNullOrUndef(CI->getArgOperand(1))) {
-        Changed = true;
-        Type *Ty = CI->getArgOperand(0)->getType();
-        new StoreInst(UndefValue::get(cast<PointerType>(Ty)->getElementType()),
-                      Constant::getNullValue(Ty),
-                      CI);
-
-        llvm::Value *NewValue = UndefValue::get(CI->getType());
-        DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: A null "
-                        "pointer-to-weak-pointer is undefined behavior.\n"
-                        "                                     Old = " << *CI <<
-                        "\n                                     New = " <<
-                        *NewValue << "\n");
-
-        CI->replaceAllUsesWith(NewValue);
-        CI->eraseFromParent();
-        continue;
-      }
-      break;
-    }
-    case IC_Retain:
-      OptimizeRetainCall(F, Inst);
-      break;
-    case IC_RetainRV:
-      if (OptimizeRetainRVCall(F, Inst))
-        continue;
-      break;
-    case IC_AutoreleaseRV:
-      OptimizeAutoreleaseRVCall(F, Inst);
-      break;
-    }
-
-    // objc_autorelease(x) -> objc_release(x) if x is otherwise unused.
-    if (IsAutorelease(Class) && Inst->use_empty()) {
-      CallInst *Call = cast<CallInst>(Inst);
-      const Value *Arg = Call->getArgOperand(0);
-      Arg = FindSingleUseIdentifiedObject(Arg);
-      if (Arg) {
-        Changed = true;
-        ++NumAutoreleases;
-
-        // Create the declaration lazily.
-        LLVMContext &C = Inst->getContext();
-        CallInst *NewCall =
-          CallInst::Create(getReleaseCallee(F.getParent()),
-                           Call->getArgOperand(0), "", Call);
-        NewCall->setMetadata(ImpreciseReleaseMDKind,
-                             MDNode::get(C, ArrayRef<Value *>()));
-
-        DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Replacing "
-                        "objc_autorelease(x) with objc_release(x) since x is "
-                        "otherwise unused.\n"
-                        "                                     Old: " << *Call <<
-                        "\n                                     New: " <<
-                        *NewCall << "\n");
-
-        EraseInstruction(Call);
-        Inst = NewCall;
-        Class = IC_Release;
-      }
-    }
-
-    // For functions which can never be passed stack arguments, add
-    // a tail keyword.
-    if (IsAlwaysTail(Class)) {
-      Changed = true;
-      DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Adding tail keyword"
-            " to function since it can never be passed stack args: " << *Inst <<
-            "\n");
-      cast<CallInst>(Inst)->setTailCall();
-    }
-
-    // Set nounwind as needed.
-    if (IsNoThrow(Class)) {
-      Changed = true;
-      DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Found no throw"
-            " class. Setting nounwind on: " << *Inst << "\n");
-      cast<CallInst>(Inst)->setDoesNotThrow();
-    }
-
-    if (!IsNoopOnNull(Class)) {
-      UsedInThisFunction |= 1 << Class;
-      continue;
-    }
-
-    const Value *Arg = GetObjCArg(Inst);
-
-    // ARC calls with null are no-ops. Delete them.
-    if (isNullOrUndef(Arg)) {
-      Changed = true;
-      ++NumNoops;
-      DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: ARC calls with "
-            " null are no-ops. Erasing: " << *Inst << "\n");
-      EraseInstruction(Inst);
-      continue;
-    }
-
-    // Keep track of which of retain, release, autorelease, and retain_block
-    // are actually present in this function.
-    UsedInThisFunction |= 1 << Class;
-
-    // If Arg is a PHI, and one or more incoming values to the
-    // PHI are null, and the call is control-equivalent to the PHI, and there
-    // are no relevant side effects between the PHI and the call, the call
-    // could be pushed up to just those paths with non-null incoming values.
-    // For now, don't bother splitting critical edges for this.
-    SmallVector<std::pair<Instruction *, const Value *>, 4> Worklist;
-    Worklist.push_back(std::make_pair(Inst, Arg));
-    do {
-      std::pair<Instruction *, const Value *> Pair = Worklist.pop_back_val();
-      Inst = Pair.first;
-      Arg = Pair.second;
-
-      const PHINode *PN = dyn_cast<PHINode>(Arg);
-      if (!PN) continue;
-
-      // Determine if the PHI has any null operands, or any incoming
-      // critical edges.
-      bool HasNull = false;
-      bool HasCriticalEdges = false;
-      for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
-        Value *Incoming =
-          StripPointerCastsAndObjCCalls(PN->getIncomingValue(i));
-        if (isNullOrUndef(Incoming))
-          HasNull = true;
-        else if (cast<TerminatorInst>(PN->getIncomingBlock(i)->back())
-                   .getNumSuccessors() != 1) {
-          HasCriticalEdges = true;
-          break;
-        }
-      }
-      // If we have null operands and no critical edges, optimize.
-      if (!HasCriticalEdges && HasNull) {
-        SmallPtrSet<Instruction *, 4> DependingInstructions;
-        SmallPtrSet<const BasicBlock *, 4> Visited;
-
-        // Check that there is nothing that cares about the reference
-        // count between the call and the phi.
-        switch (Class) {
-        case IC_Retain:
-        case IC_RetainBlock:
-          // These can always be moved up.
-          break;
-        case IC_Release:
-          // These can't be moved across things that care about the retain
-          // count.
-          FindDependencies(NeedsPositiveRetainCount, Arg,
-                           Inst->getParent(), Inst,
-                           DependingInstructions, Visited, PA);
-          break;
-        case IC_Autorelease:
-          // These can't be moved across autorelease pool scope boundaries.
-          FindDependencies(AutoreleasePoolBoundary, Arg,
-                           Inst->getParent(), Inst,
-                           DependingInstructions, Visited, PA);
-          break;
-        case IC_RetainRV:
-        case IC_AutoreleaseRV:
-          // Don't move these; the RV optimization depends on the autoreleaseRV
-          // being tail called, and the retainRV being immediately after a call
-          // (which might still happen if we get lucky with codegen layout, but
-          // it's not worth taking the chance).
-          continue;
-        default:
-          llvm_unreachable("Invalid dependence flavor");
-        }
-
-        if (DependingInstructions.size() == 1 &&
-            *DependingInstructions.begin() == PN) {
-          Changed = true;
-          ++NumPartialNoops;
-          // Clone the call into each predecessor that has a non-null value.
-          CallInst *CInst = cast<CallInst>(Inst);
-          Type *ParamTy = CInst->getArgOperand(0)->getType();
-          for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
-            Value *Incoming =
-              StripPointerCastsAndObjCCalls(PN->getIncomingValue(i));
-            if (!isNullOrUndef(Incoming)) {
-              CallInst *Clone = cast<CallInst>(CInst->clone());
-              Value *Op = PN->getIncomingValue(i);
-              Instruction *InsertPos = &PN->getIncomingBlock(i)->back();
-              if (Op->getType() != ParamTy)
-                Op = new BitCastInst(Op, ParamTy, "", InsertPos);
-              Clone->setArgOperand(0, Op);
-              Clone->insertBefore(InsertPos);
-              Worklist.push_back(std::make_pair(Clone, Incoming));
-            }
-          }
-          // Erase the original call.
-          EraseInstruction(CInst);
-          continue;
-        }
-      }
-    } while (!Worklist.empty());
-
-    DEBUG(dbgs() << "ObjCARCOpt::OptimizeIndividualCalls: Finished Queue.\n\n");
-
-  }
-}
-
-/// CheckForCFGHazards - Check for critical edges, loop boundaries, irreducible
-/// control flow, or other CFG structures where moving code across the edge
-/// would result in it being executed more.
-void
-ObjCARCOpt::CheckForCFGHazards(const BasicBlock *BB,
-                               DenseMap<const BasicBlock *, BBState> &BBStates,
-                               BBState &MyStates) const {
-  // If any top-down local-use or possible-dec has a succ which is earlier in
-  // the sequence, forget it.
-  for (BBState::ptr_iterator I = MyStates.top_down_ptr_begin(),
-       E = MyStates.top_down_ptr_end(); I != E; ++I)
-    switch (I->second.GetSeq()) {
-    default: break;
-    case S_Use: {
-      const Value *Arg = I->first;
-      const TerminatorInst *TI = cast<TerminatorInst>(&BB->back());
-      bool SomeSuccHasSame = false;
-      bool AllSuccsHaveSame = true;
-      PtrState &S = I->second;
-      succ_const_iterator SI(TI), SE(TI, false);
-
-      // If the terminator is an invoke marked with the
-      // clang.arc.no_objc_arc_exceptions metadata, the unwind edge can be
-      // ignored, for ARC purposes.
-      if (isa<InvokeInst>(TI) && TI->getMetadata(NoObjCARCExceptionsMDKind))
-        --SE;
-
-      for (; SI != SE; ++SI) {
-        Sequence SuccSSeq = S_None;
-        bool SuccSRRIKnownSafe = false;
-        // If VisitBottomUp has pointer information for this successor, take
-        // what we know about it.
-        DenseMap<const BasicBlock *, BBState>::iterator BBI =
-          BBStates.find(*SI);
-        assert(BBI != BBStates.end());
-        const PtrState &SuccS = BBI->second.getPtrBottomUpState(Arg);
-        SuccSSeq = SuccS.GetSeq();
-        SuccSRRIKnownSafe = SuccS.RRI.KnownSafe;
-        switch (SuccSSeq) {
-        case S_None:
-        case S_CanRelease: {
-          if (!S.RRI.KnownSafe && !SuccSRRIKnownSafe) {
-            S.ClearSequenceProgress();
-            break;
-          }
-          continue;
-        }
-        case S_Use:
-          SomeSuccHasSame = true;
-          break;
-        case S_Stop:
-        case S_Release:
-        case S_MovableRelease:
-          if (!S.RRI.KnownSafe && !SuccSRRIKnownSafe)
-            AllSuccsHaveSame = false;
-          break;
-        case S_Retain:
-          llvm_unreachable("bottom-up pointer in retain state!");
-        }
-      }
-      // If the state at the other end of any of the successor edges
-      // matches the current state, require all edges to match. This
-      // guards against loops in the middle of a sequence.
-      if (SomeSuccHasSame && !AllSuccsHaveSame)
-        S.ClearSequenceProgress();
-      break;
-    }
-    case S_CanRelease: {
-      const Value *Arg = I->first;
-      const TerminatorInst *TI = cast<TerminatorInst>(&BB->back());
-      bool SomeSuccHasSame = false;
-      bool AllSuccsHaveSame = true;
-      PtrState &S = I->second;
-      succ_const_iterator SI(TI), SE(TI, false);
-
-      // If the terminator is an invoke marked with the
-      // clang.arc.no_objc_arc_exceptions metadata, the unwind edge can be
-      // ignored, for ARC purposes.
-      if (isa<InvokeInst>(TI) && TI->getMetadata(NoObjCARCExceptionsMDKind))
-        --SE;
-
-      for (; SI != SE; ++SI) {
-        Sequence SuccSSeq = S_None;
-        bool SuccSRRIKnownSafe = false;
-        // If VisitBottomUp has pointer information for this successor, take
-        // what we know about it.
-        DenseMap<const BasicBlock *, BBState>::iterator BBI =
-          BBStates.find(*SI);
-        assert(BBI != BBStates.end());
-        const PtrState &SuccS = BBI->second.getPtrBottomUpState(Arg);
-        SuccSSeq = SuccS.GetSeq();
-        SuccSRRIKnownSafe = SuccS.RRI.KnownSafe;
-        switch (SuccSSeq) {
-        case S_None: {
-          if (!S.RRI.KnownSafe && !SuccSRRIKnownSafe) {
-            S.ClearSequenceProgress();
-            break;
-          }
-          continue;
-        }
-        case S_CanRelease:
-          SomeSuccHasSame = true;
-          break;
-        case S_Stop:
-        case S_Release:
-        case S_MovableRelease:
-        case S_Use:
-          if (!S.RRI.KnownSafe && !SuccSRRIKnownSafe)
-            AllSuccsHaveSame = false;
-          break;
-        case S_Retain:
-          llvm_unreachable("bottom-up pointer in retain state!");
-        }
-      }
-      // If the state at the other end of any of the successor edges
-      // matches the current state, require all edges to match. This
-      // guards against loops in the middle of a sequence.
-      if (SomeSuccHasSame && !AllSuccsHaveSame)
-        S.ClearSequenceProgress();
-      break;
-    }
-    }
-}
-
-bool
-ObjCARCOpt::VisitInstructionBottomUp(Instruction *Inst,
-                                     BasicBlock *BB,
-                                     MapVector<Value *, RRInfo> &Retains,
-                                     BBState &MyStates) {
-  bool NestingDetected = false;
-  InstructionClass Class = GetInstructionClass(Inst);
-  const Value *Arg = 0;
-
-  switch (Class) {
-  case IC_Release: {
-    Arg = GetObjCArg(Inst);
-
-    PtrState &S = MyStates.getPtrBottomUpState(Arg);
-
-    // If we see two releases in a row on the same pointer. If so, make
-    // a note, and we'll cicle back to revisit it after we've
-    // hopefully eliminated the second release, which may allow us to
-    // eliminate the first release too.
-    // Theoretically we could implement removal of nested retain+release
-    // pairs by making PtrState hold a stack of states, but this is
-    // simple and avoids adding overhead for the non-nested case.
-    if (S.GetSeq() == S_Release || S.GetSeq() == S_MovableRelease)
-      NestingDetected = true;
-
-    MDNode *ReleaseMetadata = Inst->getMetadata(ImpreciseReleaseMDKind);
-    S.ResetSequenceProgress(ReleaseMetadata ? S_MovableRelease : S_Release);
-    S.RRI.ReleaseMetadata = ReleaseMetadata;
-    S.RRI.KnownSafe = S.IsKnownIncremented();
-    S.RRI.IsTailCallRelease = cast<CallInst>(Inst)->isTailCall();
-    S.RRI.Calls.insert(Inst);
-
-    S.SetKnownPositiveRefCount();
-    break;
-  }
-  case IC_RetainBlock:
-    // An objc_retainBlock call with just a use may need to be kept,
-    // because it may be copying a block from the stack to the heap.
-    if (!IsRetainBlockOptimizable(Inst))
-      break;
-    // FALLTHROUGH
-  case IC_Retain:
-  case IC_RetainRV: {
-    Arg = GetObjCArg(Inst);
-
-    PtrState &S = MyStates.getPtrBottomUpState(Arg);
-    S.SetKnownPositiveRefCount();
-
-    switch (S.GetSeq()) {
-    case S_Stop:
-    case S_Release:
-    case S_MovableRelease:
-    case S_Use:
-      S.RRI.ReverseInsertPts.clear();
-      // FALL THROUGH
-    case S_CanRelease:
-      // Don't do retain+release tracking for IC_RetainRV, because it's
-      // better to let it remain as the first instruction after a call.
-      if (Class != IC_RetainRV) {
-        S.RRI.IsRetainBlock = Class == IC_RetainBlock;
-        Retains[Inst] = S.RRI;
-      }
-      S.ClearSequenceProgress();
-      break;
-    case S_None:
-      break;
-    case S_Retain:
-      llvm_unreachable("bottom-up pointer in retain state!");
-    }
-    return NestingDetected;
-  }
-  case IC_AutoreleasepoolPop:
-    // Conservatively, clear MyStates for all known pointers.
-    MyStates.clearBottomUpPointers();
-    return NestingDetected;
-  case IC_AutoreleasepoolPush:
-  case IC_None:
-    // These are irrelevant.
-    return NestingDetected;
-  default:
-    break;
-  }
-
-  // Consider any other possible effects of this instruction on each
-  // pointer being tracked.
-  for (BBState::ptr_iterator MI = MyStates.bottom_up_ptr_begin(),
-       ME = MyStates.bottom_up_ptr_end(); MI != ME; ++MI) {
-    const Value *Ptr = MI->first;
-    if (Ptr == Arg)
-      continue; // Handled above.
-    PtrState &S = MI->second;
-    Sequence Seq = S.GetSeq();
-
-    // Check for possible releases.
-    if (CanAlterRefCount(Inst, Ptr, PA, Class)) {
-      S.ClearRefCount();
-      switch (Seq) {
-      case S_Use:
-        S.SetSeq(S_CanRelease);
-        continue;
-      case S_CanRelease:
-      case S_Release:
-      case S_MovableRelease:
-      case S_Stop:
-      case S_None:
-        break;
-      case S_Retain:
-        llvm_unreachable("bottom-up pointer in retain state!");
-      }
-    }
-
-    // Check for possible direct uses.
-    switch (Seq) {
-    case S_Release:
-    case S_MovableRelease:
-      if (CanUse(Inst, Ptr, PA, Class)) {
-        assert(S.RRI.ReverseInsertPts.empty());
-        // If this is an invoke instruction, we're scanning it as part of
-        // one of its successor blocks, since we can't insert code after it
-        // in its own block, and we don't want to split critical edges.
-        if (isa<InvokeInst>(Inst))
-          S.RRI.ReverseInsertPts.insert(BB->getFirstInsertionPt());
-        else
-          S.RRI.ReverseInsertPts.insert(llvm::next(BasicBlock::iterator(Inst)));
-        S.SetSeq(S_Use);
-      } else if (Seq == S_Release &&
-                 (Class == IC_User || Class == IC_CallOrUser)) {
-        // Non-movable releases depend on any possible objc pointer use.
-        S.SetSeq(S_Stop);
-        assert(S.RRI.ReverseInsertPts.empty());
-        // As above; handle invoke specially.
-        if (isa<InvokeInst>(Inst))
-          S.RRI.ReverseInsertPts.insert(BB->getFirstInsertionPt());
-        else
-          S.RRI.ReverseInsertPts.insert(llvm::next(BasicBlock::iterator(Inst)));
-      }
-      break;
-    case S_Stop:
-      if (CanUse(Inst, Ptr, PA, Class))
-        S.SetSeq(S_Use);
-      break;
-    case S_CanRelease:
-    case S_Use:
-    case S_None:
-      break;
-    case S_Retain:
-      llvm_unreachable("bottom-up pointer in retain state!");
-    }
-  }
-
-  return NestingDetected;
-}
-
-bool
-ObjCARCOpt::VisitBottomUp(BasicBlock *BB,
-                          DenseMap<const BasicBlock *, BBState> &BBStates,
-                          MapVector<Value *, RRInfo> &Retains) {
-  bool NestingDetected = false;
-  BBState &MyStates = BBStates[BB];
-
-  // Merge the states from each successor to compute the initial state
-  // for the current block.
-  BBState::edge_iterator SI(MyStates.succ_begin()),
-                         SE(MyStates.succ_end());
-  if (SI != SE) {
-    const BasicBlock *Succ = *SI;
-    DenseMap<const BasicBlock *, BBState>::iterator I = BBStates.find(Succ);
-    assert(I != BBStates.end());
-    MyStates.InitFromSucc(I->second);
-    ++SI;
-    for (; SI != SE; ++SI) {
-      Succ = *SI;
-      I = BBStates.find(Succ);
-      assert(I != BBStates.end());
-      MyStates.MergeSucc(I->second);
-    }
-  }
-
-  // Visit all the instructions, bottom-up.
-  for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; --I) {
-    Instruction *Inst = llvm::prior(I);
-
-    // Invoke instructions are visited as part of their successors (below).
-    if (isa<InvokeInst>(Inst))
-      continue;
-
-    NestingDetected |= VisitInstructionBottomUp(Inst, BB, Retains, MyStates);
-  }
-
-  // If there's a predecessor with an invoke, visit the invoke as if it were
-  // part of this block, since we can't insert code after an invoke in its own
-  // block, and we don't want to split critical edges.
-  for (BBState::edge_iterator PI(MyStates.pred_begin()),
-       PE(MyStates.pred_end()); PI != PE; ++PI) {
-    BasicBlock *Pred = *PI;
-    if (InvokeInst *II = dyn_cast<InvokeInst>(&Pred->back()))
-      NestingDetected |= VisitInstructionBottomUp(II, BB, Retains, MyStates);
-  }
-
-  return NestingDetected;
-}
-
-bool
-ObjCARCOpt::VisitInstructionTopDown(Instruction *Inst,
-                                    DenseMap<Value *, RRInfo> &Releases,
-                                    BBState &MyStates) {
-  bool NestingDetected = false;
-  InstructionClass Class = GetInstructionClass(Inst);
-  const Value *Arg = 0;
-
-  switch (Class) {
-  case IC_RetainBlock:
-    // An objc_retainBlock call with just a use may need to be kept,
-    // because it may be copying a block from the stack to the heap.
-    if (!IsRetainBlockOptimizable(Inst))
-      break;
-    // FALLTHROUGH
-  case IC_Retain:
-  case IC_RetainRV: {
-    Arg = GetObjCArg(Inst);
-
-    PtrState &S = MyStates.getPtrTopDownState(Arg);
-
-    // Don't do retain+release tracking for IC_RetainRV, because it's
-    // better to let it remain as the first instruction after a call.
-    if (Class != IC_RetainRV) {
-      // If we see two retains in a row on the same pointer. If so, make
-      // a note, and we'll cicle back to revisit it after we've
-      // hopefully eliminated the second retain, which may allow us to
-      // eliminate the first retain too.
-      // Theoretically we could implement removal of nested retain+release
-      // pairs by making PtrState hold a stack of states, but this is
-      // simple and avoids adding overhead for the non-nested case.
-      if (S.GetSeq() == S_Retain)
-        NestingDetected = true;
-
-      S.ResetSequenceProgress(S_Retain);
-      S.RRI.IsRetainBlock = Class == IC_RetainBlock;
-      S.RRI.KnownSafe = S.IsKnownIncremented();
-      S.RRI.Calls.insert(Inst);
-    }
-
-    S.SetKnownPositiveRefCount();
-
-    // A retain can be a potential use; procede to the generic checking
-    // code below.
-    break;
-  }
-  case IC_Release: {
-    Arg = GetObjCArg(Inst);
-
-    PtrState &S = MyStates.getPtrTopDownState(Arg);
-    S.ClearRefCount();
-
-    switch (S.GetSeq()) {
-    case S_Retain:
-    case S_CanRelease:
-      S.RRI.ReverseInsertPts.clear();
-      // FALL THROUGH
-    case S_Use:
-      S.RRI.ReleaseMetadata = Inst->getMetadata(ImpreciseReleaseMDKind);
-      S.RRI.IsTailCallRelease = cast<CallInst>(Inst)->isTailCall();
-      Releases[Inst] = S.RRI;
-      S.ClearSequenceProgress();
-      break;
-    case S_None:
-      break;
-    case S_Stop:
-    case S_Release:
-    case S_MovableRelease:
-      llvm_unreachable("top-down pointer in release state!");
-    }
-    break;
-  }
-  case IC_AutoreleasepoolPop:
-    // Conservatively, clear MyStates for all known pointers.
-    MyStates.clearTopDownPointers();
-    return NestingDetected;
-  case IC_AutoreleasepoolPush:
-  case IC_None:
-    // These are irrelevant.
-    return NestingDetected;
-  default:
-    break;
-  }
-
-  // Consider any other possible effects of this instruction on each
-  // pointer being tracked.
-  for (BBState::ptr_iterator MI = MyStates.top_down_ptr_begin(),
-       ME = MyStates.top_down_ptr_end(); MI != ME; ++MI) {
-    const Value *Ptr = MI->first;
-    if (Ptr == Arg)
-      continue; // Handled above.
-    PtrState &S = MI->second;
-    Sequence Seq = S.GetSeq();
-
-    // Check for possible releases.
-    if (CanAlterRefCount(Inst, Ptr, PA, Class)) {
-      S.ClearRefCount();
-      switch (Seq) {
-      case S_Retain:
-        S.SetSeq(S_CanRelease);
-        assert(S.RRI.ReverseInsertPts.empty());
-        S.RRI.ReverseInsertPts.insert(Inst);
-
-        // One call can't cause a transition from S_Retain to S_CanRelease
-        // and S_CanRelease to S_Use. If we've made the first transition,
-        // we're done.
-        continue;
-      case S_Use:
-      case S_CanRelease:
-      case S_None:
-        break;
-      case S_Stop:
-      case S_Release:
-      case S_MovableRelease:
-        llvm_unreachable("top-down pointer in release state!");
-      }
-    }
-
-    // Check for possible direct uses.
-    switch (Seq) {
-    case S_CanRelease:
-      if (CanUse(Inst, Ptr, PA, Class))
-        S.SetSeq(S_Use);
-      break;
-    case S_Retain:
-    case S_Use:
-    case S_None:
-      break;
-    case S_Stop:
-    case S_Release:
-    case S_MovableRelease:
-      llvm_unreachable("top-down pointer in release state!");
-    }
-  }
-
-  return NestingDetected;
-}
-
-bool
-ObjCARCOpt::VisitTopDown(BasicBlock *BB,
-                         DenseMap<const BasicBlock *, BBState> &BBStates,
-                         DenseMap<Value *, RRInfo> &Releases) {
-  bool NestingDetected = false;
-  BBState &MyStates = BBStates[BB];
-
-  // Merge the states from each predecessor to compute the initial state
-  // for the current block.
-  BBState::edge_iterator PI(MyStates.pred_begin()),
-                         PE(MyStates.pred_end());
-  if (PI != PE) {
-    const BasicBlock *Pred = *PI;
-    DenseMap<const BasicBlock *, BBState>::iterator I = BBStates.find(Pred);
-    assert(I != BBStates.end());
-    MyStates.InitFromPred(I->second);
-    ++PI;
-    for (; PI != PE; ++PI) {
-      Pred = *PI;
-      I = BBStates.find(Pred);
-      assert(I != BBStates.end());
-      MyStates.MergePred(I->second);
-    }
-  }
-
-  // Visit all the instructions, top-down.
-  for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
-    Instruction *Inst = I;
-    NestingDetected |= VisitInstructionTopDown(Inst, Releases, MyStates);
-  }
-
-  CheckForCFGHazards(BB, BBStates, MyStates);
-  return NestingDetected;
-}
-
-static void
-ComputePostOrders(Function &F,
-                  SmallVectorImpl<BasicBlock *> &PostOrder,
-                  SmallVectorImpl<BasicBlock *> &ReverseCFGPostOrder,
-                  unsigned NoObjCARCExceptionsMDKind,
-                  DenseMap<const BasicBlock *, BBState> &BBStates) {
-  /// Visited - The visited set, for doing DFS walks.
-  SmallPtrSet<BasicBlock *, 16> Visited;
-
-  // Do DFS, computing the PostOrder.
-  SmallPtrSet<BasicBlock *, 16> OnStack;
-  SmallVector<std::pair<BasicBlock *, succ_iterator>, 16> SuccStack;
-
-  // Functions always have exactly one entry block, and we don't have
-  // any other block that we treat like an entry block.
-  BasicBlock *EntryBB = &F.getEntryBlock();
-  BBState &MyStates = BBStates[EntryBB];
-  MyStates.SetAsEntry();
-  TerminatorInst *EntryTI = cast<TerminatorInst>(&EntryBB->back());
-  SuccStack.push_back(std::make_pair(EntryBB, succ_iterator(EntryTI)));
-  Visited.insert(EntryBB);
-  OnStack.insert(EntryBB);
-  do {
-  dfs_next_succ:
-    BasicBlock *CurrBB = SuccStack.back().first;
-    TerminatorInst *TI = cast<TerminatorInst>(&CurrBB->back());
-    succ_iterator SE(TI, false);
-
-    // If the terminator is an invoke marked with the
-    // clang.arc.no_objc_arc_exceptions metadata, the unwind edge can be
-    // ignored, for ARC purposes.
-    if (isa<InvokeInst>(TI) && TI->getMetadata(NoObjCARCExceptionsMDKind))
-      --SE;
-
-    while (SuccStack.back().second != SE) {
-      BasicBlock *SuccBB = *SuccStack.back().second++;
-      if (Visited.insert(SuccBB)) {
-        TerminatorInst *TI = cast<TerminatorInst>(&SuccBB->back());
-        SuccStack.push_back(std::make_pair(SuccBB, succ_iterator(TI)));
-        BBStates[CurrBB].addSucc(SuccBB);
-        BBState &SuccStates = BBStates[SuccBB];
-        SuccStates.addPred(CurrBB);
-        OnStack.insert(SuccBB);
-        goto dfs_next_succ;
-      }
-
-      if (!OnStack.count(SuccBB)) {
-        BBStates[CurrBB].addSucc(SuccBB);
-        BBStates[SuccBB].addPred(CurrBB);
-      }
-    }
-    OnStack.erase(CurrBB);
-    PostOrder.push_back(CurrBB);
-    SuccStack.pop_back();
-  } while (!SuccStack.empty());
-
-  Visited.clear();
-
-  // Do reverse-CFG DFS, computing the reverse-CFG PostOrder.
-  // Functions may have many exits, and there also blocks which we treat
-  // as exits due to ignored edges.
-  SmallVector<std::pair<BasicBlock *, BBState::edge_iterator>, 16> PredStack;
-  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
-    BasicBlock *ExitBB = I;
-    BBState &MyStates = BBStates[ExitBB];
-    if (!MyStates.isExit())
-      continue;
-
-    MyStates.SetAsExit();
-
-    PredStack.push_back(std::make_pair(ExitBB, MyStates.pred_begin()));
-    Visited.insert(ExitBB);
-    while (!PredStack.empty()) {
-    reverse_dfs_next_succ:
-      BBState::edge_iterator PE = BBStates[PredStack.back().first].pred_end();
-      while (PredStack.back().second != PE) {
-        BasicBlock *BB = *PredStack.back().second++;
-        if (Visited.insert(BB)) {
-          PredStack.push_back(std::make_pair(BB, BBStates[BB].pred_begin()));
-          goto reverse_dfs_next_succ;
-        }
-      }
-      ReverseCFGPostOrder.push_back(PredStack.pop_back_val().first);
-    }
-  }
-}
-
-// Visit - Visit the function both top-down and bottom-up.
-bool
-ObjCARCOpt::Visit(Function &F,
-                  DenseMap<const BasicBlock *, BBState> &BBStates,
-                  MapVector<Value *, RRInfo> &Retains,
-                  DenseMap<Value *, RRInfo> &Releases) {
-
-  // Use reverse-postorder traversals, because we magically know that loops
-  // will be well behaved, i.e. they won't repeatedly call retain on a single
-  // pointer without doing a release. We can't use the ReversePostOrderTraversal
-  // class here because we want the reverse-CFG postorder to consider each
-  // function exit point, and we want to ignore selected cycle edges.
-  SmallVector<BasicBlock *, 16> PostOrder;
-  SmallVector<BasicBlock *, 16> ReverseCFGPostOrder;
-  ComputePostOrders(F, PostOrder, ReverseCFGPostOrder,
-                    NoObjCARCExceptionsMDKind,
-                    BBStates);
-
-  // Use reverse-postorder on the reverse CFG for bottom-up.
-  bool BottomUpNestingDetected = false;
-  for (SmallVectorImpl<BasicBlock *>::const_reverse_iterator I =
-       ReverseCFGPostOrder.rbegin(), E = ReverseCFGPostOrder.rend();
-       I != E; ++I)
-    BottomUpNestingDetected |= VisitBottomUp(*I, BBStates, Retains);
-
-  // Use reverse-postorder for top-down.
-  bool TopDownNestingDetected = false;
-  for (SmallVectorImpl<BasicBlock *>::const_reverse_iterator I =
-       PostOrder.rbegin(), E = PostOrder.rend();
-       I != E; ++I)
-    TopDownNestingDetected |= VisitTopDown(*I, BBStates, Releases);
-
-  return TopDownNestingDetected && BottomUpNestingDetected;
-}
-
-/// MoveCalls - Move the calls in RetainsToMove and ReleasesToMove.
-void ObjCARCOpt::MoveCalls(Value *Arg,
-                           RRInfo &RetainsToMove,
-                           RRInfo &ReleasesToMove,
-                           MapVector<Value *, RRInfo> &Retains,
-                           DenseMap<Value *, RRInfo> &Releases,
-                           SmallVectorImpl<Instruction *> &DeadInsts,
-                           Module *M) {
-  Type *ArgTy = Arg->getType();
-  Type *ParamTy = PointerType::getUnqual(Type::getInt8Ty(ArgTy->getContext()));
-
-  // Insert the new retain and release calls.
-  for (SmallPtrSet<Instruction *, 2>::const_iterator
-       PI = ReleasesToMove.ReverseInsertPts.begin(),
-       PE = ReleasesToMove.ReverseInsertPts.end(); PI != PE; ++PI) {
-    Instruction *InsertPt = *PI;
-    Value *MyArg = ArgTy == ParamTy ? Arg :
-                   new BitCastInst(Arg, ParamTy, "", InsertPt);
-    CallInst *Call =
-      CallInst::Create(RetainsToMove.IsRetainBlock ?
-                         getRetainBlockCallee(M) : getRetainCallee(M),
-                       MyArg, "", InsertPt);
-    Call->setDoesNotThrow();
-    if (RetainsToMove.IsRetainBlock)
-      Call->setMetadata(CopyOnEscapeMDKind,
-                        MDNode::get(M->getContext(), ArrayRef<Value *>()));
-    else
-      Call->setTailCall();
-  }
-  for (SmallPtrSet<Instruction *, 2>::const_iterator
-       PI = RetainsToMove.ReverseInsertPts.begin(),
-       PE = RetainsToMove.ReverseInsertPts.end(); PI != PE; ++PI) {
-    Instruction *InsertPt = *PI;
-    Value *MyArg = ArgTy == ParamTy ? Arg :
-                   new BitCastInst(Arg, ParamTy, "", InsertPt);
-    CallInst *Call = CallInst::Create(getReleaseCallee(M), MyArg,
-                                      "", InsertPt);
-    // Attach a clang.imprecise_release metadata tag, if appropriate.
-    if (MDNode *M = ReleasesToMove.ReleaseMetadata)
-      Call->setMetadata(ImpreciseReleaseMDKind, M);
-    Call->setDoesNotThrow();
-    if (ReleasesToMove.IsTailCallRelease)
-      Call->setTailCall();
-  }
-
-  // Delete the original retain and release calls.
-  for (SmallPtrSet<Instruction *, 2>::const_iterator
-       AI = RetainsToMove.Calls.begin(),
-       AE = RetainsToMove.Calls.end(); AI != AE; ++AI) {
-    Instruction *OrigRetain = *AI;
-    Retains.blot(OrigRetain);
-    DeadInsts.push_back(OrigRetain);
-  }
-  for (SmallPtrSet<Instruction *, 2>::const_iterator
-       AI = ReleasesToMove.Calls.begin(),
-       AE = ReleasesToMove.Calls.end(); AI != AE; ++AI) {
-    Instruction *OrigRelease = *AI;
-    Releases.erase(OrigRelease);
-    DeadInsts.push_back(OrigRelease);
-  }
-}
-
-/// PerformCodePlacement - Identify pairings between the retains and releases,
-/// and delete and/or move them.
-bool
-ObjCARCOpt::PerformCodePlacement(DenseMap<const BasicBlock *, BBState>
-                                   &BBStates,
-                                 MapVector<Value *, RRInfo> &Retains,
-                                 DenseMap<Value *, RRInfo> &Releases,
-                                 Module *M) {
-  bool AnyPairsCompletelyEliminated = false;
-  RRInfo RetainsToMove;
-  RRInfo ReleasesToMove;
-  SmallVector<Instruction *, 4> NewRetains;
-  SmallVector<Instruction *, 4> NewReleases;
-  SmallVector<Instruction *, 8> DeadInsts;
-
-  // Visit each retain.
-  for (MapVector<Value *, RRInfo>::const_iterator I = Retains.begin(),
-       E = Retains.end(); I != E; ++I) {
-    Value *V = I->first;
-    if (!V) continue; // blotted
-
-    Instruction *Retain = cast<Instruction>(V);
-    Value *Arg = GetObjCArg(Retain);
-
-    // If the object being released is in static or stack storage, we know it's
-    // not being managed by ObjC reference counting, so we can delete pairs
-    // regardless of what possible decrements or uses lie between them.
-    bool KnownSafe = isa<Constant>(Arg) || isa<AllocaInst>(Arg);
-
-    // A constant pointer can't be pointing to an object on the heap. It may
-    // be reference-counted, but it won't be deleted.
-    if (const LoadInst *LI = dyn_cast<LoadInst>(Arg))
-      if (const GlobalVariable *GV =
-            dyn_cast<GlobalVariable>(
-              StripPointerCastsAndObjCCalls(LI->getPointerOperand())))
-        if (GV->isConstant())
-          KnownSafe = true;
-
-    // If a pair happens in a region where it is known that the reference count
-    // is already incremented, we can similarly ignore possible decrements.
-    bool KnownSafeTD = true, KnownSafeBU = true;
-
-    // Connect the dots between the top-down-collected RetainsToMove and
-    // bottom-up-collected ReleasesToMove to form sets of related calls.
-    // This is an iterative process so that we connect multiple releases
-    // to multiple retains if needed.
-    unsigned OldDelta = 0;
-    unsigned NewDelta = 0;
-    unsigned OldCount = 0;
-    unsigned NewCount = 0;
-    bool FirstRelease = true;
-    bool FirstRetain = true;
-    NewRetains.push_back(Retain);
-    for (;;) {
-      for (SmallVectorImpl<Instruction *>::const_iterator
-           NI = NewRetains.begin(), NE = NewRetains.end(); NI != NE; ++NI) {
-        Instruction *NewRetain = *NI;
-        MapVector<Value *, RRInfo>::const_iterator It = Retains.find(NewRetain);
-        assert(It != Retains.end());
-        const RRInfo &NewRetainRRI = It->second;
-        KnownSafeTD &= NewRetainRRI.KnownSafe;
-        for (SmallPtrSet<Instruction *, 2>::const_iterator
-             LI = NewRetainRRI.Calls.begin(),
-             LE = NewRetainRRI.Calls.end(); LI != LE; ++LI) {
-          Instruction *NewRetainRelease = *LI;
-          DenseMap<Value *, RRInfo>::const_iterator Jt =
-            Releases.find(NewRetainRelease);
-          if (Jt == Releases.end())
-            goto next_retain;
-          const RRInfo &NewRetainReleaseRRI = Jt->second;
-          assert(NewRetainReleaseRRI.Calls.count(NewRetain));
-          if (ReleasesToMove.Calls.insert(NewRetainRelease)) {
-            OldDelta -=
-              BBStates[NewRetainRelease->getParent()].GetAllPathCount();
-
-            // Merge the ReleaseMetadata and IsTailCallRelease values.
-            if (FirstRelease) {
-              ReleasesToMove.ReleaseMetadata =
-                NewRetainReleaseRRI.ReleaseMetadata;
-              ReleasesToMove.IsTailCallRelease =
-                NewRetainReleaseRRI.IsTailCallRelease;
-              FirstRelease = false;
-            } else {
-              if (ReleasesToMove.ReleaseMetadata !=
-                    NewRetainReleaseRRI.ReleaseMetadata)
-                ReleasesToMove.ReleaseMetadata = 0;
-              if (ReleasesToMove.IsTailCallRelease !=
-                    NewRetainReleaseRRI.IsTailCallRelease)
-                ReleasesToMove.IsTailCallRelease = false;
-            }
-
-            // Collect the optimal insertion points.
-            if (!KnownSafe)
-              for (SmallPtrSet<Instruction *, 2>::const_iterator
-                   RI = NewRetainReleaseRRI.ReverseInsertPts.begin(),
-                   RE = NewRetainReleaseRRI.ReverseInsertPts.end();
-                   RI != RE; ++RI) {
-                Instruction *RIP = *RI;
-                if (ReleasesToMove.ReverseInsertPts.insert(RIP))
-                  NewDelta -= BBStates[RIP->getParent()].GetAllPathCount();
-              }
-            NewReleases.push_back(NewRetainRelease);
-          }
-        }
-      }
-      NewRetains.clear();
-      if (NewReleases.empty()) break;
-
-      // Back the other way.
-      for (SmallVectorImpl<Instruction *>::const_iterator
-           NI = NewReleases.begin(), NE = NewReleases.end(); NI != NE; ++NI) {
-        Instruction *NewRelease = *NI;
-        DenseMap<Value *, RRInfo>::const_iterator It =
-          Releases.find(NewRelease);
-        assert(It != Releases.end());
-        const RRInfo &NewReleaseRRI = It->second;
-        KnownSafeBU &= NewReleaseRRI.KnownSafe;
-        for (SmallPtrSet<Instruction *, 2>::const_iterator
-             LI = NewReleaseRRI.Calls.begin(),
-             LE = NewReleaseRRI.Calls.end(); LI != LE; ++LI) {
-          Instruction *NewReleaseRetain = *LI;
-          MapVector<Value *, RRInfo>::const_iterator Jt =
-            Retains.find(NewReleaseRetain);
-          if (Jt == Retains.end())
-            goto next_retain;
-          const RRInfo &NewReleaseRetainRRI = Jt->second;
-          assert(NewReleaseRetainRRI.Calls.count(NewRelease));
-          if (RetainsToMove.Calls.insert(NewReleaseRetain)) {
-            unsigned PathCount =
-              BBStates[NewReleaseRetain->getParent()].GetAllPathCount();
-            OldDelta += PathCount;
-            OldCount += PathCount;
-
-            // Merge the IsRetainBlock values.
-            if (FirstRetain) {
-              RetainsToMove.IsRetainBlock = NewReleaseRetainRRI.IsRetainBlock;
-              FirstRetain = false;
-            } else if (ReleasesToMove.IsRetainBlock !=
-                       NewReleaseRetainRRI.IsRetainBlock)
-              // It's not possible to merge the sequences if one uses
-              // objc_retain and the other uses objc_retainBlock.
-              goto next_retain;
-
-            // Collect the optimal insertion points.
-            if (!KnownSafe)
-              for (SmallPtrSet<Instruction *, 2>::const_iterator
-                   RI = NewReleaseRetainRRI.ReverseInsertPts.begin(),
-                   RE = NewReleaseRetainRRI.ReverseInsertPts.end();
-                   RI != RE; ++RI) {
-                Instruction *RIP = *RI;
-                if (RetainsToMove.ReverseInsertPts.insert(RIP)) {
-                  PathCount = BBStates[RIP->getParent()].GetAllPathCount();
-                  NewDelta += PathCount;
-                  NewCount += PathCount;
-                }
-              }
-            NewRetains.push_back(NewReleaseRetain);
-          }
-        }
-      }
-      NewReleases.clear();
-      if (NewRetains.empty()) break;
-    }
-
-    // If the pointer is known incremented or nested, we can safely delete the
-    // pair regardless of what's between them.
-    if (KnownSafeTD || KnownSafeBU) {
-      RetainsToMove.ReverseInsertPts.clear();
-      ReleasesToMove.ReverseInsertPts.clear();
-      NewCount = 0;
-    } else {
-      // Determine whether the new insertion points we computed preserve the
-      // balance of retain and release calls through the program.
-      // TODO: If the fully aggressive solution isn't valid, try to find a
-      // less aggressive solution which is.
-      if (NewDelta != 0)
-        goto next_retain;
-    }
-
-    // Determine whether the original call points are balanced in the retain and
-    // release calls through the program. If not, conservatively don't touch
-    // them.
-    // TODO: It's theoretically possible to do code motion in this case, as
-    // long as the existing imbalances are maintained.
-    if (OldDelta != 0)
-      goto next_retain;
-
-    // Ok, everything checks out and we're all set. Let's move some code!
-    Changed = true;
-    assert(OldCount != 0 && "Unreachable code?");
-    AnyPairsCompletelyEliminated = NewCount == 0;
-    NumRRs += OldCount - NewCount;
-    MoveCalls(Arg, RetainsToMove, ReleasesToMove,
-              Retains, Releases, DeadInsts, M);
-
-  next_retain:
-    NewReleases.clear();
-    NewRetains.clear();
-    RetainsToMove.clear();
-    ReleasesToMove.clear();
-  }
-
-  // Now that we're done moving everything, we can delete the newly dead
-  // instructions, as we no longer need them as insert points.
-  while (!DeadInsts.empty())
-    EraseInstruction(DeadInsts.pop_back_val());
-
-  return AnyPairsCompletelyEliminated;
-}
-
-/// OptimizeWeakCalls - Weak pointer optimizations.
-void ObjCARCOpt::OptimizeWeakCalls(Function &F) {
-  // First, do memdep-style RLE and S2L optimizations. We can't use memdep
-  // itself because it uses AliasAnalysis and we need to do provenance
-  // queries instead.
-  for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
-    Instruction *Inst = &*I++;
-
-    DEBUG(dbgs() << "ObjCARCOpt::OptimizeWeakCalls: Visiting: " << *Inst <<
-          "\n");
-
-    InstructionClass Class = GetBasicInstructionClass(Inst);
-    if (Class != IC_LoadWeak && Class != IC_LoadWeakRetained)
-      continue;
-
-    // Delete objc_loadWeak calls with no users.
-    if (Class == IC_LoadWeak && Inst->use_empty()) {
-      Inst->eraseFromParent();
-      continue;
-    }
-
-    // TODO: For now, just look for an earlier available version of this value
-    // within the same block. Theoretically, we could do memdep-style non-local
-    // analysis too, but that would want caching. A better approach would be to
-    // use the technique that EarlyCSE uses.
-    inst_iterator Current = llvm::prior(I);
-    BasicBlock *CurrentBB = Current.getBasicBlockIterator();
-    for (BasicBlock::iterator B = CurrentBB->begin(),
-                              J = Current.getInstructionIterator();
-         J != B; --J) {
-      Instruction *EarlierInst = &*llvm::prior(J);
-      InstructionClass EarlierClass = GetInstructionClass(EarlierInst);
-      switch (EarlierClass) {
-      case IC_LoadWeak:
-      case IC_LoadWeakRetained: {
-        // If this is loading from the same pointer, replace this load's value
-        // with that one.
-        CallInst *Call = cast<CallInst>(Inst);
-        CallInst *EarlierCall = cast<CallInst>(EarlierInst);
-        Value *Arg = Call->getArgOperand(0);
-        Value *EarlierArg = EarlierCall->getArgOperand(0);
-        switch (PA.getAA()->alias(Arg, EarlierArg)) {
-        case AliasAnalysis::MustAlias:
-          Changed = true;
-          // If the load has a builtin retain, insert a plain retain for it.
-          if (Class == IC_LoadWeakRetained) {
-            CallInst *CI =
-              CallInst::Create(getRetainCallee(F.getParent()), EarlierCall,
-                               "", Call);
-            CI->setTailCall();
-          }
-          // Zap the fully redundant load.
-          Call->replaceAllUsesWith(EarlierCall);
-          Call->eraseFromParent();
-          goto clobbered;
-        case AliasAnalysis::MayAlias:
-        case AliasAnalysis::PartialAlias:
-          goto clobbered;
-        case AliasAnalysis::NoAlias:
-          break;
-        }
-        break;
-      }
-      case IC_StoreWeak:
-      case IC_InitWeak: {
-        // If this is storing to the same pointer and has the same size etc.
-        // replace this load's value with the stored value.
-        CallInst *Call = cast<CallInst>(Inst);
-        CallInst *EarlierCall = cast<CallInst>(EarlierInst);
-        Value *Arg = Call->getArgOperand(0);
-        Value *EarlierArg = EarlierCall->getArgOperand(0);
-        switch (PA.getAA()->alias(Arg, EarlierArg)) {
-        case AliasAnalysis::MustAlias:
-          Changed = true;
-          // If the load has a builtin retain, insert a plain retain for it.
-          if (Class == IC_LoadWeakRetained) {
-            CallInst *CI =
-              CallInst::Create(getRetainCallee(F.getParent()), EarlierCall,
-                               "", Call);
-            CI->setTailCall();
-          }
-          // Zap the fully redundant load.
-          Call->replaceAllUsesWith(EarlierCall->getArgOperand(1));
-          Call->eraseFromParent();
-          goto clobbered;
-        case AliasAnalysis::MayAlias:
-        case AliasAnalysis::PartialAlias:
-          goto clobbered;
-        case AliasAnalysis::NoAlias:
-          break;
-        }
-        break;
-      }
-      case IC_MoveWeak:
-      case IC_CopyWeak:
-        // TOOD: Grab the copied value.
-        goto clobbered;
-      case IC_AutoreleasepoolPush:
-      case IC_None:
-      case IC_User:
-        // Weak pointers are only modified through the weak entry points
-        // (and arbitrary calls, which could call the weak entry points).
-        break;
-      default:
-        // Anything else could modify the weak pointer.
-        goto clobbered;
-      }
-    }
-  clobbered:;
-  }
-
-  // Then, for each destroyWeak with an alloca operand, check to see if
-  // the alloca and all its users can be zapped.
-  for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
-    Instruction *Inst = &*I++;
-    InstructionClass Class = GetBasicInstructionClass(Inst);
-    if (Class != IC_DestroyWeak)
-      continue;
-
-    CallInst *Call = cast<CallInst>(Inst);
-    Value *Arg = Call->getArgOperand(0);
-    if (AllocaInst *Alloca = dyn_cast<AllocaInst>(Arg)) {
-      for (Value::use_iterator UI = Alloca->use_begin(),
-           UE = Alloca->use_end(); UI != UE; ++UI) {
-        const Instruction *UserInst = cast<Instruction>(*UI);
-        switch (GetBasicInstructionClass(UserInst)) {
-        case IC_InitWeak:
-        case IC_StoreWeak:
-        case IC_DestroyWeak:
-          continue;
-        default:
-          goto done;
-        }
-      }
-      Changed = true;
-      for (Value::use_iterator UI = Alloca->use_begin(),
-           UE = Alloca->use_end(); UI != UE; ) {
-        CallInst *UserInst = cast<CallInst>(*UI++);
-        switch (GetBasicInstructionClass(UserInst)) {
-        case IC_InitWeak:
-        case IC_StoreWeak:
-          // These functions return their second argument.
-          UserInst->replaceAllUsesWith(UserInst->getArgOperand(1));
-          break;
-        case IC_DestroyWeak:
-          // No return value.
-          break;
-        default:
-          llvm_unreachable("alloca really is used!");
-        }
-        UserInst->eraseFromParent();
-      }
-      Alloca->eraseFromParent();
-    done:;
-    }
-  }
-
-  DEBUG(dbgs() << "ObjCARCOpt::OptimizeWeakCalls: Finished List.\n\n");
-
-}
-
-/// OptimizeSequences - Identify program paths which execute sequences of
-/// retains and releases which can be eliminated.
-bool ObjCARCOpt::OptimizeSequences(Function &F) {
-  /// Releases, Retains - These are used to store the results of the main flow
-  /// analysis. These use Value* as the key instead of Instruction* so that the
-  /// map stays valid when we get around to rewriting code and calls get
-  /// replaced by arguments.
-  DenseMap<Value *, RRInfo> Releases;
-  MapVector<Value *, RRInfo> Retains;
-
-  /// BBStates, This is used during the traversal of the function to track the
-  /// states for each identified object at each block.
-  DenseMap<const BasicBlock *, BBState> BBStates;
-
-  // Analyze the CFG of the function, and all instructions.
-  bool NestingDetected = Visit(F, BBStates, Retains, Releases);
-
-  // Transform.
-  return PerformCodePlacement(BBStates, Retains, Releases, F.getParent()) &&
-         NestingDetected;
-}
-
-/// OptimizeReturns - Look for this pattern:
-/// \code
-///    %call = call i8* @something(...)
-///    %2 = call i8* @objc_retain(i8* %call)
-///    %3 = call i8* @objc_autorelease(i8* %2)
-///    ret i8* %3
-/// \endcode
-/// And delete the retain and autorelease.
-///
-/// Otherwise if it's just this:
-/// \code
-///    %3 = call i8* @objc_autorelease(i8* %2)
-///    ret i8* %3
-/// \endcode
-/// convert the autorelease to autoreleaseRV.
-void ObjCARCOpt::OptimizeReturns(Function &F) {
-  if (!F.getReturnType()->isPointerTy())
-    return;
-
-  SmallPtrSet<Instruction *, 4> DependingInstructions;
-  SmallPtrSet<const BasicBlock *, 4> Visited;
-  for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI) {
-    BasicBlock *BB = FI;
-    ReturnInst *Ret = dyn_cast<ReturnInst>(&BB->back());
-
-    DEBUG(dbgs() << "ObjCARCOpt::OptimizeReturns: Visiting: " << *Ret << "\n");
-
-    if (!Ret) continue;
-
-    const Value *Arg = StripPointerCastsAndObjCCalls(Ret->getOperand(0));
-    FindDependencies(NeedsPositiveRetainCount, Arg,
-                     BB, Ret, DependingInstructions, Visited, PA);
-    if (DependingInstructions.size() != 1)
-      goto next_block;
-
-    {
-      CallInst *Autorelease =
-        dyn_cast_or_null<CallInst>(*DependingInstructions.begin());
-      if (!Autorelease)
-        goto next_block;
-      InstructionClass AutoreleaseClass = GetBasicInstructionClass(Autorelease);
-      if (!IsAutorelease(AutoreleaseClass))
-        goto next_block;
-      if (GetObjCArg(Autorelease) != Arg)
-        goto next_block;
-
-      DependingInstructions.clear();
-      Visited.clear();
-
-      // Check that there is nothing that can affect the reference
-      // count between the autorelease and the retain.
-      FindDependencies(CanChangeRetainCount, Arg,
-                       BB, Autorelease, DependingInstructions, Visited, PA);
-      if (DependingInstructions.size() != 1)
-        goto next_block;
-
-      {
-        CallInst *Retain =
-          dyn_cast_or_null<CallInst>(*DependingInstructions.begin());
-
-        // Check that we found a retain with the same argument.
-        if (!Retain ||
-            !IsRetain(GetBasicInstructionClass(Retain)) ||
-            GetObjCArg(Retain) != Arg)
-          goto next_block;
-
-        DependingInstructions.clear();
-        Visited.clear();
-
-        // Convert the autorelease to an autoreleaseRV, since it's
-        // returning the value.
-        if (AutoreleaseClass == IC_Autorelease) {
-          Autorelease->setCalledFunction(getAutoreleaseRVCallee(F.getParent()));
-          AutoreleaseClass = IC_AutoreleaseRV;
-        }
-
-        // Check that there is nothing that can affect the reference
-        // count between the retain and the call.
-        // Note that Retain need not be in BB.
-        FindDependencies(CanChangeRetainCount, Arg, Retain->getParent(), Retain,
-                         DependingInstructions, Visited, PA);
-        if (DependingInstructions.size() != 1)
-          goto next_block;
-
-        {
-          CallInst *Call =
-            dyn_cast_or_null<CallInst>(*DependingInstructions.begin());
-
-          // Check that the pointer is the return value of the call.
-          if (!Call || Arg != Call)
-            goto next_block;
-
-          // Check that the call is a regular call.
-          InstructionClass Class = GetBasicInstructionClass(Call);
-          if (Class != IC_CallOrUser && Class != IC_Call)
-            goto next_block;
-
-          // If so, we can zap the retain and autorelease.
-          Changed = true;
-          ++NumRets;
-          DEBUG(dbgs() << "ObjCARCOpt::OptimizeReturns: Erasing: " << *Retain
-                       << "\n                             Erasing: "
-                       << *Autorelease << "\n");
-          EraseInstruction(Retain);
-          EraseInstruction(Autorelease);
-        }
-      }
-    }
-
-  next_block:
-    DependingInstructions.clear();
-    Visited.clear();
-  }
-
-  DEBUG(dbgs() << "ObjCARCOpt::OptimizeReturns: Finished List.\n\n");
-
-}
-
-bool ObjCARCOpt::doInitialization(Module &M) {
-  if (!EnableARCOpts)
-    return false;
-
-  // If nothing in the Module uses ARC, don't do anything.
-  Run = ModuleHasARC(M);
-  if (!Run)
-    return false;
-
-  // Identify the imprecise release metadata kind.
-  ImpreciseReleaseMDKind =
-    M.getContext().getMDKindID("clang.imprecise_release");
-  CopyOnEscapeMDKind =
-    M.getContext().getMDKindID("clang.arc.copy_on_escape");
-  NoObjCARCExceptionsMDKind =
-    M.getContext().getMDKindID("clang.arc.no_objc_arc_exceptions");
-
-  // Intuitively, objc_retain and others are nocapture, however in practice
-  // they are not, because they return their argument value. And objc_release
-  // calls finalizers which can have arbitrary side effects.
-
-  // These are initialized lazily.
-  RetainRVCallee = 0;
-  AutoreleaseRVCallee = 0;
-  ReleaseCallee = 0;
-  RetainCallee = 0;
-  RetainBlockCallee = 0;
-  AutoreleaseCallee = 0;
-
-  return false;
-}
-
-bool ObjCARCOpt::runOnFunction(Function &F) {
-  if (!EnableARCOpts)
-    return false;
-
-  // If nothing in the Module uses ARC, don't do anything.
-  if (!Run)
-    return false;
-
-  Changed = false;
-
-  PA.setAA(&getAnalysis<AliasAnalysis>());
-
-  // This pass performs several distinct transformations. As a compile-time aid
-  // when compiling code that isn't ObjC, skip these if the relevant ObjC
-  // library functions aren't declared.
-
-  // Preliminary optimizations. This also computs UsedInThisFunction.
-  OptimizeIndividualCalls(F);
-
-  // Optimizations for weak pointers.
-  if (UsedInThisFunction & ((1 << IC_LoadWeak) |
-                            (1 << IC_LoadWeakRetained) |
-                            (1 << IC_StoreWeak) |
-                            (1 << IC_InitWeak) |
-                            (1 << IC_CopyWeak) |
-                            (1 << IC_MoveWeak) |
-                            (1 << IC_DestroyWeak)))
-    OptimizeWeakCalls(F);
-
-  // Optimizations for retain+release pairs.
-  if (UsedInThisFunction & ((1 << IC_Retain) |
-                            (1 << IC_RetainRV) |
-                            (1 << IC_RetainBlock)))
-    if (UsedInThisFunction & (1 << IC_Release))
-      // Run OptimizeSequences until it either stops making changes or
-      // no retain+release pair nesting is detected.
-      while (OptimizeSequences(F)) {}
-
-  // Optimizations if objc_autorelease is used.
-  if (UsedInThisFunction & ((1 << IC_Autorelease) |
-                            (1 << IC_AutoreleaseRV)))
-    OptimizeReturns(F);
-
-  return Changed;
-}
-
-void ObjCARCOpt::releaseMemory() {
-  PA.clear();
-}
-
-//===----------------------------------------------------------------------===//
-// ARC contraction.
-//===----------------------------------------------------------------------===//
-
-// TODO: ObjCARCContract could insert PHI nodes when uses aren't
-// dominated by single calls.
-
-#include "llvm/Analysis/Dominators.h"
-#include "llvm/IR/InlineAsm.h"
-#include "llvm/IR/Operator.h"
-
-STATISTIC(NumStoreStrongs, "Number objc_storeStrong calls formed");
-
-namespace {
-  /// ObjCARCContract - Late ARC optimizations.  These change the IR in a way
-  /// that makes it difficult to be analyzed by ObjCARCOpt, so it's run late.
-  class ObjCARCContract : public FunctionPass {
-    bool Changed;
-    AliasAnalysis *AA;
-    DominatorTree *DT;
-    ProvenanceAnalysis PA;
-
-    /// Run - A flag indicating whether this optimization pass should run.
-    bool Run;
-
-    /// StoreStrongCallee, etc. - Declarations for ObjC runtime
-    /// functions, for use in creating calls to them. These are initialized
-    /// lazily to avoid cluttering up the Module with unused declarations.
-    Constant *StoreStrongCallee,
-             *RetainAutoreleaseCallee, *RetainAutoreleaseRVCallee;
-
-    /// RetainRVMarker - The inline asm string to insert between calls and
-    /// RetainRV calls to make the optimization work on targets which need it.
-    const MDString *RetainRVMarker;
-
-    /// StoreStrongCalls - The set of inserted objc_storeStrong calls. If
-    /// at the end of walking the function we have found no alloca
-    /// instructions, these calls can be marked "tail".
-    SmallPtrSet<CallInst *, 8> StoreStrongCalls;
-
-    Constant *getStoreStrongCallee(Module *M);
-    Constant *getRetainAutoreleaseCallee(Module *M);
-    Constant *getRetainAutoreleaseRVCallee(Module *M);
-
-    bool ContractAutorelease(Function &F, Instruction *Autorelease,
-                             InstructionClass Class,
-                             SmallPtrSet<Instruction *, 4>
-                               &DependingInstructions,
-                             SmallPtrSet<const BasicBlock *, 4>
-                               &Visited);
-
-    void ContractRelease(Instruction *Release,
-                         inst_iterator &Iter);
-
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
-    virtual bool doInitialization(Module &M);
-    virtual bool runOnFunction(Function &F);
-
-  public:
-    static char ID;
-    ObjCARCContract() : FunctionPass(ID) {
-      initializeObjCARCContractPass(*PassRegistry::getPassRegistry());
-    }
-  };
-}
-
-char ObjCARCContract::ID = 0;
-INITIALIZE_PASS_BEGIN(ObjCARCContract,
-                      "objc-arc-contract", "ObjC ARC contraction", false, false)
-INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
-INITIALIZE_PASS_DEPENDENCY(DominatorTree)
-INITIALIZE_PASS_END(ObjCARCContract,
-                    "objc-arc-contract", "ObjC ARC contraction", false, false)
-
-Pass *llvm::createObjCARCContractPass() {
-  return new ObjCARCContract();
-}
-
-void ObjCARCContract::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.addRequired<AliasAnalysis>();
-  AU.addRequired<DominatorTree>();
-  AU.setPreservesCFG();
-}
-
-Constant *ObjCARCContract::getStoreStrongCallee(Module *M) {
-  if (!StoreStrongCallee) {
-    LLVMContext &C = M->getContext();
-    Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-    Type *I8XX = PointerType::getUnqual(I8X);
-    Type *Params[] = { I8XX, I8X };
-
-    AttributeSet Attribute = AttributeSet()
-      .addAttr(M->getContext(), AttributeSet::FunctionIndex,
-               Attribute::get(C, Attribute::NoUnwind))
-      .addAttr(M->getContext(), 1, Attribute::get(C, Attribute::NoCapture));
-
-    StoreStrongCallee =
-      M->getOrInsertFunction(
-        "objc_storeStrong",
-        FunctionType::get(Type::getVoidTy(C), Params, /*isVarArg=*/false),
-        Attribute);
-  }
-  return StoreStrongCallee;
-}
-
-Constant *ObjCARCContract::getRetainAutoreleaseCallee(Module *M) {
-  if (!RetainAutoreleaseCallee) {
-    LLVMContext &C = M->getContext();
-    Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-    Type *Params[] = { I8X };
-    FunctionType *FTy = FunctionType::get(I8X, Params, /*isVarArg=*/false);
-    AttributeSet Attribute =
-      AttributeSet().addAttr(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::get(C, Attribute::NoUnwind));
-    RetainAutoreleaseCallee =
-      M->getOrInsertFunction("objc_retainAutorelease", FTy, Attribute);
-  }
-  return RetainAutoreleaseCallee;
-}
-
-Constant *ObjCARCContract::getRetainAutoreleaseRVCallee(Module *M) {
-  if (!RetainAutoreleaseRVCallee) {
-    LLVMContext &C = M->getContext();
-    Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-    Type *Params[] = { I8X };
-    FunctionType *FTy = FunctionType::get(I8X, Params, /*isVarArg=*/false);
-    AttributeSet Attribute =
-      AttributeSet().addAttr(M->getContext(), AttributeSet::FunctionIndex,
-                            Attribute::get(C, Attribute::NoUnwind));
-    RetainAutoreleaseRVCallee =
-      M->getOrInsertFunction("objc_retainAutoreleaseReturnValue", FTy,
-                             Attribute);
-  }
-  return RetainAutoreleaseRVCallee;
-}
-
-/// ContractAutorelease - Merge an autorelease with a retain into a fused call.
-bool
-ObjCARCContract::ContractAutorelease(Function &F, Instruction *Autorelease,
-                                     InstructionClass Class,
-                                     SmallPtrSet<Instruction *, 4>
-                                       &DependingInstructions,
-                                     SmallPtrSet<const BasicBlock *, 4>
-                                       &Visited) {
-  const Value *Arg = GetObjCArg(Autorelease);
-
-  // Check that there are no instructions between the retain and the autorelease
-  // (such as an autorelease_pop) which may change the count.
-  CallInst *Retain = 0;
-  if (Class == IC_AutoreleaseRV)
-    FindDependencies(RetainAutoreleaseRVDep, Arg,
-                     Autorelease->getParent(), Autorelease,
-                     DependingInstructions, Visited, PA);
-  else
-    FindDependencies(RetainAutoreleaseDep, Arg,
-                     Autorelease->getParent(), Autorelease,
-                     DependingInstructions, Visited, PA);
-
-  Visited.clear();
-  if (DependingInstructions.size() != 1) {
-    DependingInstructions.clear();
-    return false;
-  }
-
-  Retain = dyn_cast_or_null<CallInst>(*DependingInstructions.begin());
-  DependingInstructions.clear();
-
-  if (!Retain ||
-      GetBasicInstructionClass(Retain) != IC_Retain ||
-      GetObjCArg(Retain) != Arg)
-    return false;
-
-  Changed = true;
-  ++NumPeeps;
-
-  DEBUG(dbgs() << "ObjCARCContract::ContractAutorelease: Fusing "
-                  "retain/autorelease. Erasing: " << *Autorelease << "\n"
-                  "                                      Old Retain: "
-               << *Retain << "\n");
-
-  if (Class == IC_AutoreleaseRV)
-    Retain->setCalledFunction(getRetainAutoreleaseRVCallee(F.getParent()));
-  else
-    Retain->setCalledFunction(getRetainAutoreleaseCallee(F.getParent()));
-
-  DEBUG(dbgs() << "                                      New Retain: "
-               << *Retain << "\n");
-
-  EraseInstruction(Autorelease);
-  return true;
-}
-
-/// ContractRelease - Attempt to merge an objc_release with a store, load, and
-/// objc_retain to form an objc_storeStrong. This can be a little tricky because
-/// the instructions don't always appear in order, and there may be unrelated
-/// intervening instructions.
-void ObjCARCContract::ContractRelease(Instruction *Release,
-                                      inst_iterator &Iter) {
-  LoadInst *Load = dyn_cast<LoadInst>(GetObjCArg(Release));
-  if (!Load || !Load->isSimple()) return;
-
-  // For now, require everything to be in one basic block.
-  BasicBlock *BB = Release->getParent();
-  if (Load->getParent() != BB) return;
-
-  // Walk down to find the store and the release, which may be in either order.
-  BasicBlock::iterator I = Load, End = BB->end();
-  ++I;
-  AliasAnalysis::Location Loc = AA->getLocation(Load);
-  StoreInst *Store = 0;
-  bool SawRelease = false;
-  for (; !Store || !SawRelease; ++I) {
-    if (I == End)
-      return;
-
-    Instruction *Inst = I;
-    if (Inst == Release) {
-      SawRelease = true;
-      continue;
-    }
-
-    InstructionClass Class = GetBasicInstructionClass(Inst);
-
-    // Unrelated retains are harmless.
-    if (IsRetain(Class))
-      continue;
-
-    if (Store) {
-      // The store is the point where we're going to put the objc_storeStrong,
-      // so make sure there are no uses after it.
-      if (CanUse(Inst, Load, PA, Class))
-        return;
-    } else if (AA->getModRefInfo(Inst, Loc) & AliasAnalysis::Mod) {
-      // We are moving the load down to the store, so check for anything
-      // else which writes to the memory between the load and the store.
-      Store = dyn_cast<StoreInst>(Inst);
-      if (!Store || !Store->isSimple()) return;
-      if (Store->getPointerOperand() != Loc.Ptr) return;
-    }
-  }
-
-  Value *New = StripPointerCastsAndObjCCalls(Store->getValueOperand());
-
-  // Walk up to find the retain.
-  I = Store;
-  BasicBlock::iterator Begin = BB->begin();
-  while (I != Begin && GetBasicInstructionClass(I) != IC_Retain)
-    --I;
-  Instruction *Retain = I;
-  if (GetBasicInstructionClass(Retain) != IC_Retain) return;
-  if (GetObjCArg(Retain) != New) return;
-
-  Changed = true;
-  ++NumStoreStrongs;
-
-  LLVMContext &C = Release->getContext();
-  Type *I8X = PointerType::getUnqual(Type::getInt8Ty(C));
-  Type *I8XX = PointerType::getUnqual(I8X);
-
-  Value *Args[] = { Load->getPointerOperand(), New };
-  if (Args[0]->getType() != I8XX)
-    Args[0] = new BitCastInst(Args[0], I8XX, "", Store);
-  if (Args[1]->getType() != I8X)
-    Args[1] = new BitCastInst(Args[1], I8X, "", Store);
-  CallInst *StoreStrong =
-    CallInst::Create(getStoreStrongCallee(BB->getParent()->getParent()),
-                     Args, "", Store);
-  StoreStrong->setDoesNotThrow();
-  StoreStrong->setDebugLoc(Store->getDebugLoc());
-
-  // We can't set the tail flag yet, because we haven't yet determined
-  // whether there are any escaping allocas. Remember this call, so that
-  // we can set the tail flag once we know it's safe.
-  StoreStrongCalls.insert(StoreStrong);
-
-  if (&*Iter == Store) ++Iter;
-  Store->eraseFromParent();
-  Release->eraseFromParent();
-  EraseInstruction(Retain);
-  if (Load->use_empty())
-    Load->eraseFromParent();
-}
-
-bool ObjCARCContract::doInitialization(Module &M) {
-  // If nothing in the Module uses ARC, don't do anything.
-  Run = ModuleHasARC(M);
-  if (!Run)
-    return false;
-
-  // These are initialized lazily.
-  StoreStrongCallee = 0;
-  RetainAutoreleaseCallee = 0;
-  RetainAutoreleaseRVCallee = 0;
-
-  // Initialize RetainRVMarker.
-  RetainRVMarker = 0;
-  if (NamedMDNode *NMD =
-        M.getNamedMetadata("clang.arc.retainAutoreleasedReturnValueMarker"))
-    if (NMD->getNumOperands() == 1) {
-      const MDNode *N = NMD->getOperand(0);
-      if (N->getNumOperands() == 1)
-        if (const MDString *S = dyn_cast<MDString>(N->getOperand(0)))
-          RetainRVMarker = S;
-    }
-
-  return false;
-}
-
-bool ObjCARCContract::runOnFunction(Function &F) {
-  if (!EnableARCOpts)
-    return false;
-
-  // If nothing in the Module uses ARC, don't do anything.
-  if (!Run)
-    return false;
-
-  Changed = false;
-  AA = &getAnalysis<AliasAnalysis>();
-  DT = &getAnalysis<DominatorTree>();
-
-  PA.setAA(&getAnalysis<AliasAnalysis>());
-
-  // Track whether it's ok to mark objc_storeStrong calls with the "tail"
-  // keyword. Be conservative if the function has variadic arguments.
-  // It seems that functions which "return twice" are also unsafe for the
-  // "tail" argument, because they are setjmp, which could need to
-  // return to an earlier stack state.
-  bool TailOkForStoreStrongs = !F.isVarArg() &&
-                               !F.callsFunctionThatReturnsTwice();
-
-  // For ObjC library calls which return their argument, replace uses of the
-  // argument with uses of the call return value, if it dominates the use. This
-  // reduces register pressure.
-  SmallPtrSet<Instruction *, 4> DependingInstructions;
-  SmallPtrSet<const BasicBlock *, 4> Visited;
-  for (inst_iterator I = inst_begin(&F), E = inst_end(&F); I != E; ) {
-    Instruction *Inst = &*I++;
-
-    DEBUG(dbgs() << "ObjCARCContract: Visiting: " << *Inst << "\n");
-
-    // Only these library routines return their argument. In particular,
-    // objc_retainBlock does not necessarily return its argument.
-    InstructionClass Class = GetBasicInstructionClass(Inst);
-    switch (Class) {
-    case IC_Retain:
-    case IC_FusedRetainAutorelease:
-    case IC_FusedRetainAutoreleaseRV:
-      break;
-    case IC_Autorelease:
-    case IC_AutoreleaseRV:
-      if (ContractAutorelease(F, Inst, Class, DependingInstructions, Visited))
-        continue;
-      break;
-    case IC_RetainRV: {
-      // If we're compiling for a target which needs a special inline-asm
-      // marker to do the retainAutoreleasedReturnValue optimization,
-      // insert it now.
-      if (!RetainRVMarker)
-        break;
-      BasicBlock::iterator BBI = Inst;
-      BasicBlock *InstParent = Inst->getParent();
-
-      // Step up to see if the call immediately precedes the RetainRV call.
-      // If it's an invoke, we have to cross a block boundary. And we have
-      // to carefully dodge no-op instructions.
-      do {
-        if (&*BBI == InstParent->begin()) {
-          BasicBlock *Pred = InstParent->getSinglePredecessor();
-          if (!Pred)
-            goto decline_rv_optimization;
-          BBI = Pred->getTerminator();
-          break;
-        }
-        --BBI;
-      } while (isNoopInstruction(BBI));
-
-      if (&*BBI == GetObjCArg(Inst)) {
-        DEBUG(dbgs() << "ObjCARCContract: Adding inline asm marker for "
-                        "retainAutoreleasedReturnValue optimization.\n");
-        Changed = true;
-        InlineAsm *IA =
-          InlineAsm::get(FunctionType::get(Type::getVoidTy(Inst->getContext()),
-                                           /*isVarArg=*/false),
-                         RetainRVMarker->getString(),
-                         /*Constraints=*/"", /*hasSideEffects=*/true);
-        CallInst::Create(IA, "", Inst);
-      }
-    decline_rv_optimization:
-      break;
-    }
-    case IC_InitWeak: {
-      // objc_initWeak(p, null) => *p = null
-      CallInst *CI = cast<CallInst>(Inst);
-      if (isNullOrUndef(CI->getArgOperand(1))) {
-        Value *Null =
-          ConstantPointerNull::get(cast<PointerType>(CI->getType()));
-        Changed = true;
-        new StoreInst(Null, CI->getArgOperand(0), CI);
-
-        DEBUG(dbgs() << "OBJCARCContract: Old = " << *CI << "\n"
-                     << "                 New = " << *Null << "\n");
-
-        CI->replaceAllUsesWith(Null);
-        CI->eraseFromParent();
-      }
-      continue;
-    }
-    case IC_Release:
-      ContractRelease(Inst, I);
-      continue;
-    case IC_User:
-      // Be conservative if the function has any alloca instructions.
-      // Technically we only care about escaping alloca instructions,
-      // but this is sufficient to handle some interesting cases.
-      if (isa<AllocaInst>(Inst))
-        TailOkForStoreStrongs = false;
-      continue;
-    default:
-      continue;
-    }
-
-    DEBUG(dbgs() << "ObjCARCContract: Finished List.\n\n");
-
-    // Don't use GetObjCArg because we don't want to look through bitcasts
-    // and such; to do the replacement, the argument must have type i8*.
-    const Value *Arg = cast<CallInst>(Inst)->getArgOperand(0);
-    for (;;) {
-      // If we're compiling bugpointed code, don't get in trouble.
-      if (!isa<Instruction>(Arg) && !isa<Argument>(Arg))
-        break;
-      // Look through the uses of the pointer.
-      for (Value::const_use_iterator UI = Arg->use_begin(), UE = Arg->use_end();
-           UI != UE; ) {
-        Use &U = UI.getUse();
-        unsigned OperandNo = UI.getOperandNo();
-        ++UI; // Increment UI now, because we may unlink its element.
-
-        // If the call's return value dominates a use of the call's argument
-        // value, rewrite the use to use the return value. We check for
-        // reachability here because an unreachable call is considered to
-        // trivially dominate itself, which would lead us to rewriting its
-        // argument in terms of its return value, which would lead to
-        // infinite loops in GetObjCArg.
-        if (DT->isReachableFromEntry(U) && DT->dominates(Inst, U)) {
-          Changed = true;
-          Instruction *Replacement = Inst;
-          Type *UseTy = U.get()->getType();
-          if (PHINode *PHI = dyn_cast<PHINode>(U.getUser())) {
-            // For PHI nodes, insert the bitcast in the predecessor block.
-            unsigned ValNo = PHINode::getIncomingValueNumForOperand(OperandNo);
-            BasicBlock *BB = PHI->getIncomingBlock(ValNo);
-            if (Replacement->getType() != UseTy)
-              Replacement = new BitCastInst(Replacement, UseTy, "",
-                                            &BB->back());
-            // While we're here, rewrite all edges for this PHI, rather
-            // than just one use at a time, to minimize the number of
-            // bitcasts we emit.
-            for (unsigned i = 0, e = PHI->getNumIncomingValues(); i != e; ++i)
-              if (PHI->getIncomingBlock(i) == BB) {
-                // Keep the UI iterator valid.
-                if (&PHI->getOperandUse(
-                      PHINode::getOperandNumForIncomingValue(i)) ==
-                    &UI.getUse())
-                  ++UI;
-                PHI->setIncomingValue(i, Replacement);
-              }
-          } else {
-            if (Replacement->getType() != UseTy)
-              Replacement = new BitCastInst(Replacement, UseTy, "",
-                                            cast<Instruction>(U.getUser()));
-            U.set(Replacement);
-          }
-        }
-      }
-
-      // If Arg is a no-op casted pointer, strip one level of casts and iterate.
-      if (const BitCastInst *BI = dyn_cast<BitCastInst>(Arg))
-        Arg = BI->getOperand(0);
-      else if (isa<GEPOperator>(Arg) &&
-               cast<GEPOperator>(Arg)->hasAllZeroIndices())
-        Arg = cast<GEPOperator>(Arg)->getPointerOperand();
-      else if (isa<GlobalAlias>(Arg) &&
-               !cast<GlobalAlias>(Arg)->mayBeOverridden())
-        Arg = cast<GlobalAlias>(Arg)->getAliasee();
-      else
-        break;
-    }
-  }
-
-  // If this function has no escaping allocas or suspicious vararg usage,
-  // objc_storeStrong calls can be marked with the "tail" keyword.
-  if (TailOkForStoreStrongs)
-    for (SmallPtrSet<CallInst *, 8>::iterator I = StoreStrongCalls.begin(),
-         E = StoreStrongCalls.end(); I != E; ++I)
-      (*I)->setTailCall();
-  StoreStrongCalls.clear();
-
-  return Changed;
-}
diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index 3e935d8..e30a274 100644
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -271,13 +271,6 @@ public:
     return I->second;
   }
 
-  /*LatticeVal getStructLatticeValueFor(Value *V, unsigned i) const {
-    DenseMap<std::pair<Value*, unsigned>, LatticeVal>::const_iterator I =
-      StructValueState.find(std::make_pair(V, i));
-    assert(I != StructValueState.end() && "V is not in valuemap!");
-    return I->second;
-  }*/
-
   /// getTrackedRetVals - Get the inferred return value map.
   ///
   const DenseMap<Function*, LatticeVal> &getTrackedRetVals() {
@@ -710,9 +703,6 @@ void SCCPSolver::visitPHINode(PHINode &PN) {
     markConstant(&PN, OperandVal);      // Acquire operand value
 }
 
-
-
-
 void SCCPSolver::visitReturnInst(ReturnInst &I) {
   if (I.getNumOperands() == 0) return;  // ret void
 
@@ -1185,7 +1175,7 @@ void SCCPSolver::Solve() {
       DEBUG(dbgs() << "\nPopped off OI-WL: " << *I << '\n');
 
       // "I" got into the work list because it either made the transition from
-      // bottom to constant
+      // bottom to constant, or to overdefined.
       //
       // Anything on this worklist that is overdefined need not be visited
       // since all of its users will have already been marked as overdefined
diff --git a/lib/Transforms/Scalar/SROA.cpp b/lib/Transforms/Scalar/SROA.cpp
index 4204171..e90fe90 100644
--- a/lib/Transforms/Scalar/SROA.cpp
+++ b/lib/Transforms/Scalar/SROA.cpp
@@ -43,14 +43,12 @@
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/Module.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/InstVisitor.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Utils/Local.h"
@@ -411,9 +409,9 @@ static Value *foldSelectInst(SelectInst &SI) {
   // early on.
   if (ConstantInt *CI = dyn_cast<ConstantInt>(SI.getCondition()))
     return SI.getOperand(1+CI->isZero());
-  if (SI.getOperand(1) == SI.getOperand(2)) {
+  if (SI.getOperand(1) == SI.getOperand(2))
     return SI.getOperand(1);
-  }
+
   return 0;
 }
 
@@ -621,7 +619,7 @@ private:
   }
 
   // Disable SRoA for any intrinsics except for lifetime invariants.
-  // FIXME: What about debug instrinsics? This matches old behavior, but
+  // FIXME: What about debug intrinsics? This matches old behavior, but
   // doesn't make sense.
   void visitIntrinsicInst(IntrinsicInst &II) {
     if (!IsOffsetKnown)
@@ -1141,8 +1139,7 @@ void AllocaPartitioning::print(raw_ostream &OS, const_iterator I,
 
 void AllocaPartitioning::printUsers(raw_ostream &OS, const_iterator I,
                                     StringRef Indent) const {
-  for (const_use_iterator UI = use_begin(I), UE = use_end(I);
-       UI != UE; ++UI) {
+  for (const_use_iterator UI = use_begin(I), UE = use_end(I); UI != UE; ++UI) {
     if (!UI->U)
       continue; // Skip dead uses.
     OS << Indent << "  [" << UI->BeginOffset << "," << UI->EndOffset << ") "
@@ -1170,8 +1167,7 @@ void AllocaPartitioning::print(raw_ostream &OS) const {
   }
 
   OS << "Partitioning of alloca: " << AI << "\n";
-  unsigned Num = 0;
-  for (const_iterator I = begin(), E = end(); I != E; ++I, ++Num) {
+  for (const_iterator I = begin(), E = end(); I != E; ++I) {
     print(OS, I);
     printUsers(OS, I);
   }
@@ -1242,7 +1238,7 @@ public:
     for (SmallVector<DbgValueInst *, 4>::const_iterator I = DVIs.begin(),
            E = DVIs.end(); I != E; ++I) {
       DbgValueInst *DVI = *I;
-      Value *Arg = NULL;
+      Value *Arg = 0;
       if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
         // If an argument is zero extended then use argument directly. The ZExt
         // may be zapped by an optimization pass in future.
@@ -1277,7 +1273,7 @@ namespace {
 /// 1) It takes allocations of aggregates and analyzes the ways in which they
 ///    are used to try to split them into smaller allocations, ideally of
 ///    a single scalar data type. It will split up memcpy and memset accesses
-///    as necessary and try to isolate invidual scalar accesses.
+///    as necessary and try to isolate individual scalar accesses.
 /// 2) It will transform accesses into forms which are suitable for SSA value
 ///    promotion. This can be replacing a memset with a scalar store of an
 ///    integer value, or it can involve speculating operations on a PHI or
@@ -1439,8 +1435,7 @@ private:
     // We can only transform this if it is safe to push the loads into the
     // predecessor blocks. The only thing to watch out for is that we can't put
     // a possibly trapping load in the predecessor if it is a critical edge.
-    for (unsigned Idx = 0, Num = PN.getNumIncomingValues(); Idx != Num;
-         ++Idx) {
+    for (unsigned Idx = 0, Num = PN.getNumIncomingValues(); Idx != Num; ++Idx) {
       TerminatorInst *TI = PN.getIncomingBlock(Idx)->getTerminator();
       Value *InVal = PN.getIncomingValue(Idx);
 
@@ -1483,7 +1478,7 @@ private:
                                           PN.getName() + ".sroa.speculated");
 
     // Get the TBAA tag and alignment to use from one of the loads.  It doesn't
-    // matter which one we get and if any differ, it doesn't matter.
+    // matter which one we get and if any differ.
     LoadInst *SomeLoad = cast<LoadInst>(Loads.back());
     MDNode *TBAATag = SomeLoad->getMetadata(LLVMContext::MD_tbaa);
     unsigned Align = SomeLoad->getAlignment();
@@ -1816,7 +1811,7 @@ static Value *getNaturalGEPWithOffset(IRBuilder<> &IRB, const DataLayout &TD,
 /// The strategy for finding the more natural GEPs is to peel off layers of the
 /// pointer, walking back through bit casts and GEPs, searching for a base
 /// pointer from which we can compute a natural GEP with the desired
-/// properities. The algorithm tries to fold as many constant indices into
+/// properties. The algorithm tries to fold as many constant indices into
 /// a single GEP as possible, thus making each GEP more independent of the
 /// surrounding code.
 static Value *getAdjustedPtr(IRBuilder<> &IRB, const DataLayout &TD,
@@ -2062,9 +2057,9 @@ static bool isIntegerWideningViable(const DataLayout &TD,
 
   uint64_t Size = TD.getTypeStoreSize(AllocaTy);
 
-  // Check the uses to ensure the uses are (likely) promoteable integer uses.
+  // Check the uses to ensure the uses are (likely) promotable integer uses.
   // Also ensure that the alloca has a covering load or store. We don't want
-  // to widen the integer operotains only to fail to promote due to some other
+  // to widen the integer operations only to fail to promote due to some other
   // unsplittable entry (which we may make splittable later).
   bool WholeAllocaOp = false;
   for (; I != E; ++I) {
@@ -2283,7 +2278,7 @@ class AllocaPartitionRewriter : public InstVisitor<AllocaPartitionRewriter,
 
   // If we are rewriting an alloca partition which can be written as pure
   // vector operations, we stash extra information here. When VecTy is
-  // non-null, we have some strict guarantees about the rewriten alloca:
+  // non-null, we have some strict guarantees about the rewritten alloca:
   //   - The new alloca is exactly the size of the vector type here.
   //   - The accesses all either map to the entire vector or to a single
   //     element.
@@ -2636,7 +2631,7 @@ private:
   ///
   /// Note that this routine assumes an i8 is a byte. If that isn't true, don't
   /// call this routine.
-  /// FIXME: Heed the abvice above.
+  /// FIXME: Heed the advice above.
   ///
   /// \param V The i8 value to splat.
   /// \param Size The number of bytes in the output (assuming i8 is one byte)
@@ -2971,6 +2966,7 @@ private:
     else
       New = IRB.CreateLifetimeEnd(Ptr, Size);
 
+    (void)New;
     DEBUG(dbgs() << "          to: " << *New << "\n");
     return true;
   }
@@ -3147,9 +3143,8 @@ private:
     void emitFunc(Type *Ty, Value *&Agg, const Twine &Name) {
       assert(Ty->isSingleValueType());
       // Load the single value and insert it using the indices.
-      Value *Load = IRB.CreateLoad(IRB.CreateInBoundsGEP(Ptr, GEPIndices,
-                                                         Name + ".gep"),
-                                   Name + ".load");
+      Value *GEP = IRB.CreateInBoundsGEP(Ptr, GEPIndices, Name + ".gep");
+      Value *Load = IRB.CreateLoad(GEP, Name + ".load");
       Agg = IRB.CreateInsertValue(Agg, Load, Indices, Name + ".insert");
       DEBUG(dbgs() << "          to: " << *Load << "\n");
     }
@@ -3422,7 +3417,7 @@ bool SROA::rewriteAllocaPartition(AllocaInst &AI,
   // Check for the case where we're going to rewrite to a new alloca of the
   // exact same type as the original, and with the same access offsets. In that
   // case, re-use the existing alloca, but still run through the rewriter to
-  // performe phi and select speculation.
+  // perform phi and select speculation.
   AllocaInst *NewAI;
   if (AllocaTy == AI.getAllocatedType()) {
     assert(PI->BeginOffset == 0 &&
@@ -3589,7 +3584,7 @@ void SROA::deleteDeadInstructions(SmallPtrSet<AllocaInst*, 4> &DeletedAllocas) {
 /// If there is a domtree available, we attempt to promote using the full power
 /// of mem2reg. Otherwise, we build and use the AllocaPromoter above which is
 /// based on the SSAUpdater utilities. This function returns whether any
-/// promotion occured.
+/// promotion occurred.
 bool SROA::promoteAllocas(Function &F) {
   if (PromotableAllocas.empty())
     return false;
diff --git a/lib/Transforms/Scalar/Scalar.cpp b/lib/Transforms/Scalar/Scalar.cpp
index 35d2fa0..8a9c7da 100644
--- a/lib/Transforms/Scalar/Scalar.cpp
+++ b/lib/Transforms/Scalar/Scalar.cpp
@@ -50,11 +50,6 @@ void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeLowerAtomicPass(Registry);
   initializeLowerExpectIntrinsicPass(Registry);
   initializeMemCpyOptPass(Registry);
-  initializeObjCARCAliasAnalysisPass(Registry);
-  initializeObjCARCAPElimPass(Registry);
-  initializeObjCARCExpandPass(Registry);
-  initializeObjCARCContractPass(Registry);
-  initializeObjCARCOptPass(Registry);
   initializeReassociatePass(Registry);
   initializeRegToMemPass(Registry);
   initializeSCCPPass(Registry);
diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index d5cefa3..916b37d 100644
--- a/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -165,7 +165,7 @@ bool SimplifyLibCalls::runOnFunction(Function &F) {
     for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
       // Ignore non-calls.
       CallInst *CI = dyn_cast<CallInst>(I++);
-      if (!CI) continue;
+      if (!CI || CI->hasFnAttr(Attribute::NoBuiltin)) continue;
 
       // Ignore indirect calls and calls to non-external functions.
       Function *Callee = CI->getCalledFunction();
diff --git a/lib/Transforms/Scalar/TailRecursionElimination.cpp b/lib/Transforms/Scalar/TailRecursionElimination.cpp
index 6572e09..2002e68 100644
--- a/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ b/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -58,6 +58,7 @@
 #include "llvm/Analysis/InlineCost.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/Loads.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
@@ -79,11 +80,15 @@ STATISTIC(NumAccumAdded, "Number of accumulators introduced");
 
 namespace {
   struct TailCallElim : public FunctionPass {
+    const TargetTransformInfo *TTI;
+
     static char ID; // Pass identification, replacement for typeid
     TailCallElim() : FunctionPass(ID) {
       initializeTailCallElimPass(*PassRegistry::getPassRegistry());
     }
 
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const;
+
     virtual bool runOnFunction(Function &F);
 
   private:
@@ -109,14 +114,21 @@ namespace {
 }
 
 char TailCallElim::ID = 0;
-INITIALIZE_PASS(TailCallElim, "tailcallelim",
-                "Tail Call Elimination", false, false)
+INITIALIZE_PASS_BEGIN(TailCallElim, "tailcallelim",
+                      "Tail Call Elimination", false, false)
+INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
+INITIALIZE_PASS_END(TailCallElim, "tailcallelim",
+                    "Tail Call Elimination", false, false)
 
 // Public interface to the TailCallElimination pass
 FunctionPass *llvm::createTailCallEliminationPass() {
   return new TailCallElim();
 }
 
+void TailCallElim::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<TargetTransformInfo>();
+}
+
 /// AllocaMightEscapeToCalls - Return true if this alloca may be accessed by
 /// callees of this function.  We only do very simple analysis right now, this
 /// could be expanded in the future to use mod/ref information for particular
@@ -151,6 +163,7 @@ bool TailCallElim::runOnFunction(Function &F) {
   // right, so don't even try to convert it...
   if (F.getFunctionType()->isVarArg()) return false;
 
+  TTI = &getAnalysis<TargetTransformInfo>();
   BasicBlock *OldEntry = 0;
   bool TailCallsAreMarkedTail = false;
   SmallVector<PHINode*, 8> ArgumentPHIs;
@@ -391,7 +404,8 @@ TailCallElim::FindTRECandidate(Instruction *TI,
   if (BB == &F->getEntryBlock() &&
       FirstNonDbg(BB->front()) == CI &&
       FirstNonDbg(llvm::next(BB->begin())) == TI &&
-      callIsSmall(CI)) {
+      CI->getCalledFunction() &&
+      !TTI->isLoweredToCall(CI->getCalledFunction())) {
     // A single-block function with just a call and a return. Check that
     // the arguments match.
     CallSite::arg_iterator I = CallSite(CI).arg_begin(),