X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FIR%2FConstants.cpp;h=cb7c9e63059ad86c1a92ae44b479b402ea7dc18f;hb=be63d589633bbfa068b923c60eaaeee1b27647c5;hp=e67e78e595372944689b8c8085f7f29a27aa17a2;hpb=55d8f6d49023de5182efbb29d0b3bd0035909d62;p=oota-llvm.git

diff --git a/lib/IR/Constants.cpp b/lib/IR/Constants.cpp
index e67e78e5953..cb7c9e63059 100644
--- a/lib/IR/Constants.cpp
+++ b/lib/IR/Constants.cpp
@@ -21,6 +21,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/GetElementPtrTypeIterator.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Module.h"
@@ -28,7 +29,6 @@
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"
@@ -47,6 +47,16 @@ bool Constant::isNegativeZeroValue() const {
   if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
     return CFP->isZero() && CFP->isNegative();
 
+  // Equivalent for a vector of -0.0's.
+  if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this))
+    if (ConstantFP *SplatCFP = dyn_cast_or_null<ConstantFP>(CV->getSplatValue()))
+      if (SplatCFP && SplatCFP->isZero() && SplatCFP->isNegative())
+        return true;
+
+  // We've already handled true FP case; any other FP vectors can't represent -0.0.
+  if (getType()->isFPOrFPVectorTy())
+    return false;
+
   // Otherwise, just use +0.0.
   return isNullValue();
 }
@@ -97,6 +107,50 @@ bool Constant::isAllOnesValue() const {
   return false;
 }
 
+bool Constant::isOneValue() const {
+  // Check for 1 integers
+  if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
+    return CI->isOne();
+
+  // Check for FP which are bitcasted from 1 integers
+  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
+    return CFP->getValueAPF().bitcastToAPInt() == 1;
+
+  // Check for constant vectors which are splats of 1 values.
+  if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
+    if (Constant *Splat = CV->getSplatValue())
+      return Splat->isOneValue();
+
+  // Check for constant vectors which are splats of 1 values.
+  if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this))
+    if (Constant *Splat = CV->getSplatValue())
+      return Splat->isOneValue();
+
+  return false;
+}
+
+bool Constant::isMinSignedValue() const {
+  // Check for INT_MIN integers
+  if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
+    return CI->isMinValue(/*isSigned=*/true);
+
+  // Check for FP which are bitcasted from INT_MIN integers
+  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
+    return CFP->getValueAPF().bitcastToAPInt().isMinSignedValue();
+
+  // Check for constant vectors which are splats of INT_MIN values.
+  if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
+    if (Constant *Splat = CV->getSplatValue())
+      return Splat->isMinSignedValue();
+
+  // Check for constant vectors which are splats of INT_MIN values.
+  if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this))
+    if (Constant *Splat = CV->getSplatValue())
+      return Splat->isMinSignedValue();
+
+  return false;
+}
+
 // Constructor to create a '0' constant of arbitrary type...
 Constant *Constant::getNullValue(Type *Ty) {
   switch (Ty->getTypeID()) {
@@ -172,13 +226,13 @@ Constant *Constant::getAllOnesValue(Type *Ty) {
 /// 'this' is a constant expr.
 Constant *Constant::getAggregateElement(unsigned Elt) const {
   if (const ConstantStruct *CS = dyn_cast<ConstantStruct>(this))
-    return Elt < CS->getNumOperands() ? CS->getOperand(Elt) : 0;
+    return Elt < CS->getNumOperands() ? CS->getOperand(Elt) : nullptr;
 
   if (const ConstantArray *CA = dyn_cast<ConstantArray>(this))
-    return Elt < CA->getNumOperands() ? CA->getOperand(Elt) : 0;
+    return Elt < CA->getNumOperands() ? CA->getOperand(Elt) : nullptr;
 
   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
-    return Elt < CV->getNumOperands() ? CV->getOperand(Elt) : 0;
+    return Elt < CV->getNumOperands() ? CV->getOperand(Elt) : nullptr;
 
   if (const ConstantAggregateZero *CAZ =dyn_cast<ConstantAggregateZero>(this))
     return CAZ->getElementValue(Elt);
@@ -187,15 +241,16 @@ Constant *Constant::getAggregateElement(unsigned Elt) const {
     return UV->getElementValue(Elt);
 
   if (const ConstantDataSequential *CDS =dyn_cast<ConstantDataSequential>(this))
-    return Elt < CDS->getNumElements() ? CDS->getElementAsConstant(Elt) : 0;
-  return 0;
+    return Elt < CDS->getNumElements() ? CDS->getElementAsConstant(Elt)
+                                       : nullptr;
+  return nullptr;
 }
 
 Constant *Constant::getAggregateElement(Constant *Elt) const {
   assert(isa<IntegerType>(Elt->getType()) && "Index must be an integer");
   if (ConstantInt *CI = dyn_cast<ConstantInt>(Elt))
     return getAggregateElement(CI->getZExtValue());
-  return 0;
+  return nullptr;
 }
 
 
@@ -208,7 +263,7 @@ void Constant::destroyConstantImpl() {
   // Constants) that they are, in fact, invalid now and should be deleted.
   //
   while (!use_empty()) {
-    Value *V = use_back();
+    Value *V = user_back();
 #ifndef NDEBUG      // Only in -g mode...
     if (!isa<Constant>(V)) {
       dbgs() << "While deleting: " << *this
@@ -220,25 +275,28 @@ void Constant::destroyConstantImpl() {
     cast<Constant>(V)->destroyConstant();
 
     // The constant should remove itself from our use list...
-    assert((use_empty() || use_back() != V) && "Constant not removed!");
+    assert((use_empty() || user_back() != V) && "Constant not removed!");
   }
 
   // Value has no outstanding references it is safe to delete it now...
   delete this;
 }
 
-/// canTrap - Return true if evaluation of this constant could trap.  This is
-/// true for things like constant expressions that could divide by zero.
-bool Constant::canTrap() const {
-  assert(getType()->isFirstClassType() && "Cannot evaluate aggregate vals!");
+static bool canTrapImpl(const Constant *C,
+                        SmallPtrSet<const ConstantExpr *, 4> &NonTrappingOps) {
+  assert(C->getType()->isFirstClassType() && "Cannot evaluate aggregate vals!");
   // The only thing that could possibly trap are constant exprs.
-  const ConstantExpr *CE = dyn_cast<ConstantExpr>(this);
-  if (!CE) return false;
+  const ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
+  if (!CE)
+    return false;
 
   // ConstantExpr traps if any operands can trap.
-  for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
-    if (CE->getOperand(i)->canTrap())
-      return true;
+  for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) {
+    if (ConstantExpr *Op = dyn_cast<ConstantExpr>(CE->getOperand(i))) {
+      if (NonTrappingOps.insert(Op) && canTrapImpl(Op, NonTrappingOps))
+        return true;
+    }
+  }
 
   // Otherwise, only specific operations can trap.
   switch (CE->getOpcode()) {
@@ -257,39 +315,59 @@ bool Constant::canTrap() const {
   }
 }
 
-/// isThreadDependent - Return true if the value can vary between threads.
-bool Constant::isThreadDependent() const {
-  SmallPtrSet<const Constant*, 64> Visited;
-  SmallVector<const Constant*, 64> WorkList;
-  WorkList.push_back(this);
-  Visited.insert(this);
+/// canTrap - Return true if evaluation of this constant could trap.  This is
+/// true for things like constant expressions that could divide by zero.
+bool Constant::canTrap() const {
+  SmallPtrSet<const ConstantExpr *, 4> NonTrappingOps;
+  return canTrapImpl(this, NonTrappingOps);
+}
 
-  while (!WorkList.empty()) {
-    const Constant *C = WorkList.pop_back_val();
+/// Check if C contains a GlobalValue for which Predicate is true.
+static bool
+ConstHasGlobalValuePredicate(const Constant *C,
+                             bool (*Predicate)(const GlobalValue *)) {
+  SmallPtrSet<const Constant *, 8> Visited;
+  SmallVector<const Constant *, 8> WorkList;
+  WorkList.push_back(C);
+  Visited.insert(C);
 
-    if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
-      if (GV->isThreadLocal())
+  while (!WorkList.empty()) {
+    const Constant *WorkItem = WorkList.pop_back_val();
+    if (const auto *GV = dyn_cast<GlobalValue>(WorkItem))
+      if (Predicate(GV))
         return true;
-    }
-
-    for (unsigned I = 0, E = C->getNumOperands(); I != E; ++I) {
-      const Constant *D = dyn_cast<Constant>(C->getOperand(I));
-      if (!D)
+    for (const Value *Op : WorkItem->operands()) {
+      const Constant *ConstOp = dyn_cast<Constant>(Op);
+      if (!ConstOp)
         continue;
-      if (Visited.insert(D))
-        WorkList.push_back(D);
+      if (Visited.insert(ConstOp))
+        WorkList.push_back(ConstOp);
     }
   }
-
   return false;
 }
 
-/// isConstantUsed - Return true if the constant has users other than constant
-/// exprs and other dangling things.
+/// Return true if the value can vary between threads.
+bool Constant::isThreadDependent() const {
+  auto DLLImportPredicate = [](const GlobalValue *GV) {
+    return GV->isThreadLocal();
+  };
+  return ConstHasGlobalValuePredicate(this, DLLImportPredicate);
+}
+
+bool Constant::isDLLImportDependent() const {
+  auto DLLImportPredicate = [](const GlobalValue *GV) {
+    return GV->hasDLLImportStorageClass();
+  };
+  return ConstHasGlobalValuePredicate(this, DLLImportPredicate);
+}
+
+/// Return true if the constant has users other than constant exprs and other
+/// dangling things.
 bool Constant::isConstantUsed() const {
-  for (const_use_iterator UI = use_begin(), E = use_end(); UI != E; ++UI) {
-    const Constant *UC = dyn_cast<Constant>(*UI);
-    if (UC == 0 || isa<GlobalValue>(UC))
+  for (const User *U : users()) {
+    const Constant *UC = dyn_cast<Constant>(U);
+    if (!UC || isa<GlobalValue>(UC))
       return true;
 
     if (UC->isConstantUsed())
@@ -357,7 +435,7 @@ static bool removeDeadUsersOfConstant(const Constant *C) {
   if (isa<GlobalValue>(C)) return false; // Cannot remove this
 
   while (!C->use_empty()) {
-    const Constant *User = dyn_cast<Constant>(C->use_back());
+    const Constant *User = dyn_cast<Constant>(C->user_back());
     if (!User) return false; // Non-constant usage;
     if (!removeDeadUsersOfConstant(User))
       return false; // Constant wasn't dead
@@ -373,11 +451,11 @@ static bool removeDeadUsersOfConstant(const Constant *C) {
 /// that want to check to see if a global is unused, but don't want to deal
 /// with potentially dead constants hanging off of the globals.
 void Constant::removeDeadConstantUsers() const {
-  Value::const_use_iterator I = use_begin(), E = use_end();
-  Value::const_use_iterator LastNonDeadUser = E;
+  Value::const_user_iterator I = user_begin(), E = user_end();
+  Value::const_user_iterator LastNonDeadUser = E;
   while (I != E) {
     const Constant *User = dyn_cast<Constant>(*I);
-    if (User == 0) {
+    if (!User) {
       LastNonDeadUser = I;
       ++I;
       continue;
@@ -393,7 +471,7 @@ void Constant::removeDeadConstantUsers() const {
 
     // If the constant was dead, then the iterator is invalidated.
     if (LastNonDeadUser == E) {
-      I = use_begin();
+      I = user_begin();
       if (I == E) break;
     } else {
       I = LastNonDeadUser;
@@ -411,7 +489,7 @@ void Constant::removeDeadConstantUsers() const {
 void ConstantInt::anchor() { }
 
 ConstantInt::ConstantInt(IntegerType *Ty, const APInt& V)
-  : Constant(Ty, ConstantIntVal, 0, 0), Val(V) {
+  : Constant(Ty, ConstantIntVal, nullptr, 0), Val(V) {
   assert(V.getBitWidth() == Ty->getBitWidth() && "Invalid constant for type");
 }
 
@@ -463,8 +541,8 @@ ConstantInt *ConstantInt::get(LLVMContext &Context, const APInt &V) {
   // Get the corresponding integer type for the bit width of the value.
   IntegerType *ITy = IntegerType::get(Context, V.getBitWidth());
   // get an existing value or the insertion position
-  DenseMapAPIntKeyInfo::KeyTy Key(V, ITy);
-  ConstantInt *&Slot = Context.pImpl->IntConstants[Key]; 
+  LLVMContextImpl *pImpl = Context.pImpl;
+  ConstantInt *&Slot = pImpl->IntConstants[DenseMapAPIntKeyInfo::KeyTy(V, ITy)];
   if (!Slot) Slot = new ConstantInt(ITy, V);
   return Slot;
 }
@@ -564,23 +642,21 @@ Constant *ConstantFP::get(Type *Ty, StringRef Str) {
   return C; 
 }
 
+Constant *ConstantFP::getNegativeZero(Type *Ty) {
+  const fltSemantics &Semantics = *TypeToFloatSemantics(Ty->getScalarType());
+  APFloat NegZero = APFloat::getZero(Semantics, /*Negative=*/true);
+  Constant *C = get(Ty->getContext(), NegZero);
 
-ConstantFP *ConstantFP::getNegativeZero(Type *Ty) {
-  LLVMContext &Context = Ty->getContext();
-  APFloat apf = cast<ConstantFP>(Constant::getNullValue(Ty))->getValueAPF();
-  apf.changeSign();
-  return get(Context, apf);
+  if (VectorType *VTy = dyn_cast<VectorType>(Ty))
+    return ConstantVector::getSplat(VTy->getNumElements(), C);
+
+  return C;
 }
 
 
 Constant *ConstantFP::getZeroValueForNegation(Type *Ty) {
-  Type *ScalarTy = Ty->getScalarType();
-  if (ScalarTy->isFloatingPointTy()) {
-    Constant *C = getNegativeZero(ScalarTy);
-    if (VectorType *VTy = dyn_cast<VectorType>(Ty))
-      return ConstantVector::getSplat(VTy->getNumElements(), C);
-    return C;
-  }
+  if (Ty->isFPOrFPVectorTy())
+    return getNegativeZero(Ty);
 
   return Constant::getNullValue(Ty);
 }
@@ -588,11 +664,9 @@ Constant *ConstantFP::getZeroValueForNegation(Type *Ty) {
 
 // ConstantFP accessors.
 ConstantFP* ConstantFP::get(LLVMContext &Context, const APFloat& V) {
-  DenseMapAPFloatKeyInfo::KeyTy Key(V);
-
   LLVMContextImpl* pImpl = Context.pImpl;
 
-  ConstantFP *&Slot = pImpl->FPConstants[Key];
+  ConstantFP *&Slot = pImpl->FPConstants[DenseMapAPFloatKeyInfo::KeyTy(V)];
 
   if (!Slot) {
     Type *Ty;
@@ -617,14 +691,18 @@ ConstantFP* ConstantFP::get(LLVMContext &Context, const APFloat& V) {
   return Slot;
 }
 
-ConstantFP *ConstantFP::getInfinity(Type *Ty, bool Negative) {
-  const fltSemantics &Semantics = *TypeToFloatSemantics(Ty);
-  return ConstantFP::get(Ty->getContext(),
-                         APFloat::getInf(Semantics, Negative));
+Constant *ConstantFP::getInfinity(Type *Ty, bool Negative) {
+  const fltSemantics &Semantics = *TypeToFloatSemantics(Ty->getScalarType());
+  Constant *C = get(Ty->getContext(), APFloat::getInf(Semantics, Negative));
+
+  if (VectorType *VTy = dyn_cast<VectorType>(Ty))
+    return ConstantVector::getSplat(VTy->getNumElements(), C);
+
+  return C;
 }
 
 ConstantFP::ConstantFP(Type *Ty, const APFloat& V)
-  : Constant(Ty, ConstantFPVal, 0, 0), Val(V) {
+  : Constant(Ty, ConstantFPVal, nullptr, 0), Val(V) {
   assert(&V.getSemantics() == TypeToFloatSemantics(Ty) &&
          "FP type Mismatch");
 }
@@ -725,6 +803,11 @@ ConstantArray::ConstantArray(ArrayType *T, ArrayRef<Constant *> V)
 }
 
 Constant *ConstantArray::get(ArrayType *Ty, ArrayRef<Constant*> V) {
+  if (Constant *C = getImpl(Ty, V))
+    return C;
+  return Ty->getContext().pImpl->ArrayConstants.getOrCreate(Ty, V);
+}
+Constant *ConstantArray::getImpl(ArrayType *Ty, ArrayRef<Constant*> V) {
   // Empty arrays are canonicalized to ConstantAggregateZero.
   if (V.empty())
     return ConstantAggregateZero::get(Ty);
@@ -733,7 +816,6 @@ Constant *ConstantArray::get(ArrayType *Ty, ArrayRef<Constant*> V) {
     assert(V[i]->getType() == Ty->getElementType() &&
            "Wrong type in array element initializer");
   }
-  LLVMContextImpl *pImpl = Ty->getContext().pImpl;
 
   // If this is an all-zero array, return a ConstantAggregateZero object.  If
   // all undef, return an UndefValue, if "all simple", then return a
@@ -815,7 +897,7 @@ Constant *ConstantArray::get(ArrayType *Ty, ArrayRef<Constant*> V) {
   }
 
   // Otherwise, we really do want to create a ConstantArray.
-  return pImpl->ArrayConstants.getOrCreate(Ty, V);
+  return nullptr;
 }
 
 /// getTypeForElements - Return an anonymous struct type to use for a constant
@@ -903,9 +985,14 @@ ConstantVector::ConstantVector(VectorType *T, ArrayRef<Constant *> V)
 
 // ConstantVector accessors.
 Constant *ConstantVector::get(ArrayRef<Constant*> V) {
+  if (Constant *C = getImpl(V))
+    return C;
+  VectorType *Ty = VectorType::get(V.front()->getType(), V.size());
+  return Ty->getContext().pImpl->VectorConstants.getOrCreate(Ty, V);
+}
+Constant *ConstantVector::getImpl(ArrayRef<Constant*> V) {
   assert(!V.empty() && "Vectors can't be empty");
   VectorType *T = VectorType::get(V.front()->getType(), V.size());
-  LLVMContextImpl *pImpl = T->getContext().pImpl;
 
   // If this is an all-undef or all-zero vector, return a
   // ConstantAggregateZero or UndefValue.
@@ -997,7 +1084,7 @@ Constant *ConstantVector::get(ArrayRef<Constant*> V) {
 
   // Otherwise, the element type isn't compatible with ConstantDataVector, or
   // the operand list constants a ConstantExpr or something else strange.
-  return pImpl->VectorConstants.getOrCreate(T, V);
+  return nullptr;
 }
 
 Constant *ConstantVector::getSplat(unsigned NumElts, Constant *V) {
@@ -1027,7 +1114,7 @@ bool ConstantExpr::isGEPWithNoNotionalOverIndexing() const {
   if (getOpcode() != Instruction::GetElementPtr) return false;
 
   gep_type_iterator GEPI = gep_type_begin(this), E = gep_type_end(this);
-  User::const_op_iterator OI = llvm::next(this->op_begin());
+  User::const_op_iterator OI = std::next(this->op_begin());
 
   // Skip the first index, as it has no static limit.
   ++GEPI;
@@ -1108,6 +1195,7 @@ getWithOperands(ArrayRef<Constant*> Ops, Type *Ty) const {
   case Instruction::PtrToInt:
   case Instruction::IntToPtr:
   case Instruction::BitCast:
+  case Instruction::AddrSpaceCast:
     return ConstantExpr::getCast(getOpcode(), Ops[0], Ty);
   case Instruction::Select:
     return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2]);
@@ -1214,7 +1302,7 @@ ConstantAggregateZero *ConstantAggregateZero::get(Type *Ty) {
          "Cannot create an aggregate zero of non-aggregate type!");
   
   ConstantAggregateZero *&Entry = Ty->getContext().pImpl->CAZConstants[Ty];
-  if (Entry == 0)
+  if (!Entry)
     Entry = new ConstantAggregateZero(Ty);
 
   return Entry;
@@ -1262,7 +1350,7 @@ Constant *Constant::getSplatValue() const {
     return CV->getSplatValue();
   if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
     return CV->getSplatValue();
-  return 0;
+  return nullptr;
 }
 
 /// getSplatValue - If this is a splat constant, where all of the
@@ -1273,7 +1361,7 @@ Constant *ConstantVector::getSplatValue() const {
   // Then make sure all remaining elements point to the same value.
   for (unsigned I = 1, E = getNumOperands(); I < E; ++I)
     if (getOperand(I) != Elt)
-      return 0;
+      return nullptr;
   return Elt;
 }
 
@@ -1294,7 +1382,7 @@ const APInt &Constant::getUniqueInteger() const {
 
 ConstantPointerNull *ConstantPointerNull::get(PointerType *Ty) {
   ConstantPointerNull *&Entry = Ty->getContext().pImpl->CPNConstants[Ty];
-  if (Entry == 0)
+  if (!Entry)
     Entry = new ConstantPointerNull(Ty);
 
   return Entry;
@@ -1314,7 +1402,7 @@ void ConstantPointerNull::destroyConstant() {
 
 UndefValue *UndefValue::get(Type *Ty) {
   UndefValue *&Entry = Ty->getContext().pImpl->UVConstants[Ty];
-  if (Entry == 0)
+  if (!Entry)
     Entry = new UndefValue(Ty);
 
   return Entry;
@@ -1332,14 +1420,14 @@ void UndefValue::destroyConstant() {
 //
 
 BlockAddress *BlockAddress::get(BasicBlock *BB) {
-  assert(BB->getParent() != 0 && "Block must have a parent");
+  assert(BB->getParent() && "Block must have a parent");
   return get(BB->getParent(), BB);
 }
 
 BlockAddress *BlockAddress::get(Function *F, BasicBlock *BB) {
   BlockAddress *&BA =
     F->getContext().pImpl->BlockAddresses[std::make_pair(F, BB)];
-  if (BA == 0)
+  if (!BA)
     BA = new BlockAddress(F, BB);
 
   assert(BA->getFunction() == F && "Basic block moved between functions");
@@ -1354,6 +1442,17 @@ BlockAddress::BlockAddress(Function *F, BasicBlock *BB)
   BB->AdjustBlockAddressRefCount(1);
 }
 
+BlockAddress *BlockAddress::lookup(const BasicBlock *BB) {
+  if (!BB->hasAddressTaken())
+    return nullptr;
+
+  const Function *F = BB->getParent();
+  assert(F && "Block must have a parent");
+  BlockAddress *BA =
+      F->getContext().pImpl->BlockAddresses.lookup(std::make_pair(F, BB));
+  assert(BA && "Refcount and block address map disagree!");
+  return BA;
+}
 
 // destroyConstant - Remove the constant from the constant table.
 //
@@ -1371,7 +1470,7 @@ void BlockAddress::replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U) {
   BasicBlock *NewBB = getBasicBlock();
 
   if (U == &Op<0>())
-    NewF = cast<Function>(To);
+    NewF = cast<Function>(To->stripPointerCasts());
   else
     NewBB = cast<BasicBlock>(To);
 
@@ -1379,27 +1478,21 @@ void BlockAddress::replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U) {
   // and return early.
   BlockAddress *&NewBA =
     getContext().pImpl->BlockAddresses[std::make_pair(NewF, NewBB)];
-  if (NewBA == 0) {
-    getBasicBlock()->AdjustBlockAddressRefCount(-1);
-
-    // Remove the old entry, this can't cause the map to rehash (just a
-    // tombstone will get added).
-    getContext().pImpl->BlockAddresses.erase(std::make_pair(getFunction(),
-                                                            getBasicBlock()));
-    NewBA = this;
-    setOperand(0, NewF);
-    setOperand(1, NewBB);
-    getBasicBlock()->AdjustBlockAddressRefCount(1);
+  if (NewBA) {
+    replaceUsesOfWithOnConstantImpl(NewBA);
     return;
   }
 
-  // Otherwise, I do need to replace this with an existing value.
-  assert(NewBA != this && "I didn't contain From!");
-
-  // Everyone using this now uses the replacement.
-  replaceAllUsesWith(NewBA);
+  getBasicBlock()->AdjustBlockAddressRefCount(-1);
 
-  destroyConstant();
+  // Remove the old entry, this can't cause the map to rehash (just a
+  // tombstone will get added).
+  getContext().pImpl->BlockAddresses.erase(std::make_pair(getFunction(),
+                                                          getBasicBlock()));
+  NewBA = this;
+  setOperand(0, NewF);
+  setOperand(1, NewBB);
+  getBasicBlock()->AdjustBlockAddressRefCount(1);
 }
 
 //---- ConstantExpr::get() implementations.
@@ -1417,7 +1510,7 @@ static inline Constant *getFoldedCast(
   LLVMContextImpl *pImpl = Ty->getContext().pImpl;
 
   // Look up the constant in the table first to ensure uniqueness.
-  ExprMapKeyType Key(opc, C);
+  ConstantExprKeyType Key(opc, C);
 
   return pImpl->ExprConstants.getOrCreate(Ty, Key);
 }
@@ -1443,6 +1536,7 @@ Constant *ConstantExpr::getCast(unsigned oc, Constant *C, Type *Ty) {
   case Instruction::PtrToInt: return getPtrToInt(C, Ty);
   case Instruction::IntToPtr: return getIntToPtr(C, Ty);
   case Instruction::BitCast:  return getBitCast(C, Ty);
+  case Instruction::AddrSpaceCast:  return getAddrSpaceCast(C, Ty);
   }
 }
 
@@ -1471,10 +1565,26 @@ Constant *ConstantExpr::getPointerCast(Constant *S, Type *Ty) {
 
   if (Ty->isIntOrIntVectorTy())
     return getPtrToInt(S, Ty);
+
+  unsigned SrcAS = S->getType()->getPointerAddressSpace();
+  if (Ty->isPtrOrPtrVectorTy() && SrcAS != Ty->getPointerAddressSpace())
+    return getAddrSpaceCast(S, Ty);
+
   return getBitCast(S, Ty);
 }
 
-Constant *ConstantExpr::getIntegerCast(Constant *C, Type *Ty, 
+Constant *ConstantExpr::getPointerBitCastOrAddrSpaceCast(Constant *S,
+                                                         Type *Ty) {
+  assert(S->getType()->isPtrOrPtrVectorTy() && "Invalid cast");
+  assert(Ty->isPtrOrPtrVectorTy() && "Invalid cast");
+
+  if (S->getType()->getPointerAddressSpace() != Ty->getPointerAddressSpace())
+    return getAddrSpaceCast(S, Ty);
+
+  return getBitCast(S, Ty);
+}
+
+Constant *ConstantExpr::getIntegerCast(Constant *C, Type *Ty,
                                        bool isSigned) {
   assert(C->getType()->isIntOrIntVectorTy() &&
          Ty->isIntOrIntVectorTy() && "Invalid cast");
@@ -1644,6 +1754,26 @@ Constant *ConstantExpr::getBitCast(Constant *C, Type *DstTy) {
   return getFoldedCast(Instruction::BitCast, C, DstTy);
 }
 
+Constant *ConstantExpr::getAddrSpaceCast(Constant *C, Type *DstTy) {
+  assert(CastInst::castIsValid(Instruction::AddrSpaceCast, C, DstTy) &&
+         "Invalid constantexpr addrspacecast!");
+
+  // Canonicalize addrspacecasts between different pointer types by first
+  // bitcasting the pointer type and then converting the address space.
+  PointerType *SrcScalarTy = cast<PointerType>(C->getType()->getScalarType());
+  PointerType *DstScalarTy = cast<PointerType>(DstTy->getScalarType());
+  Type *DstElemTy = DstScalarTy->getElementType();
+  if (SrcScalarTy->getElementType() != DstElemTy) {
+    Type *MidTy = PointerType::get(DstElemTy, SrcScalarTy->getAddressSpace());
+    if (VectorType *VT = dyn_cast<VectorType>(DstTy)) {
+      // Handle vectors of pointers.
+      MidTy = VectorType::get(MidTy, VT->getNumElements());
+    }
+    C = getBitCast(C, MidTy);
+  }
+  return getFoldedCast(Instruction::AddrSpaceCast, C, DstTy);
+}
+
 Constant *ConstantExpr::get(unsigned Opcode, Constant *C1, Constant *C2,
                             unsigned Flags) {
   // Check the operands for consistency first.
@@ -1714,9 +1844,8 @@ Constant *ConstantExpr::get(unsigned Opcode, Constant *C1, Constant *C2,
   if (Constant *FC = ConstantFoldBinaryInstruction(Opcode, C1, C2))
     return FC;          // Fold a few common cases.
 
-  std::vector<Constant*> argVec(1, C1);
-  argVec.push_back(C2);
-  ExprMapKeyType Key(Opcode, argVec, 0, Flags);
+  Constant *ArgVec[] = { C1, C2 };
+  ConstantExprKeyType Key(Opcode, ArgVec, 0, Flags);
 
   LLVMContextImpl *pImpl = C1->getContext().pImpl;
   return pImpl->ExprConstants.getOrCreate(C1->getType(), Key);
@@ -1737,7 +1866,7 @@ Constant *ConstantExpr::getAlignOf(Type* Ty) {
   // Note that a non-inbounds gep is used, as null isn't within any object.
   Type *AligningTy = 
     StructType::get(Type::getInt1Ty(Ty->getContext()), Ty, NULL);
-  Constant *NullPtr = Constant::getNullValue(AligningTy->getPointerTo());
+  Constant *NullPtr = Constant::getNullValue(AligningTy->getPointerTo(0));
   Constant *Zero = ConstantInt::get(Type::getInt64Ty(Ty->getContext()), 0);
   Constant *One = ConstantInt::get(Type::getInt32Ty(Ty->getContext()), 1);
   Constant *Indices[2] = { Zero, One };
@@ -1792,10 +1921,8 @@ Constant *ConstantExpr::getSelect(Constant *C, Constant *V1, Constant *V2) {
   if (Constant *SC = ConstantFoldSelectInstruction(C, V1, V2))
     return SC;        // Fold common cases
 
-  std::vector<Constant*> argVec(3, C);
-  argVec[1] = V1;
-  argVec[2] = V2;
-  ExprMapKeyType Key(Instruction::Select, argVec);
+  Constant *ArgVec[] = { C, V1, V2 };
+  ConstantExprKeyType Key(Instruction::Select, ArgVec);
 
   LLVMContextImpl *pImpl = C->getContext().pImpl;
   return pImpl->ExprConstants.getOrCreate(V1->getType(), Key);
@@ -1830,8 +1957,8 @@ Constant *ConstantExpr::getGetElementPtr(Constant *C, ArrayRef<Value *> Idxs,
            "getelementptr index type missmatch");
     ArgVec.push_back(cast<Constant>(Idxs[i]));
   }
-  const ExprMapKeyType Key(Instruction::GetElementPtr, ArgVec, 0,
-                           InBounds ? GEPOperator::IsInBounds : 0);
+  const ConstantExprKeyType Key(Instruction::GetElementPtr, ArgVec, 0,
+                                InBounds ? GEPOperator::IsInBounds : 0);
 
   LLVMContextImpl *pImpl = C->getContext().pImpl;
   return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
@@ -1847,11 +1974,9 @@ ConstantExpr::getICmp(unsigned short pred, Constant *LHS, Constant *RHS) {
     return FC;          // Fold a few common cases...
 
   // Look up the constant in the table first to ensure uniqueness
-  std::vector<Constant*> ArgVec;
-  ArgVec.push_back(LHS);
-  ArgVec.push_back(RHS);
+  Constant *ArgVec[] = { LHS, RHS };
   // Get the key type with both the opcode and predicate
-  const ExprMapKeyType Key(Instruction::ICmp, ArgVec, pred);
+  const ConstantExprKeyType Key(Instruction::ICmp, ArgVec, pred);
 
   Type *ResultTy = Type::getInt1Ty(LHS->getContext());
   if (VectorType *VT = dyn_cast<VectorType>(LHS->getType()))
@@ -1870,11 +1995,9 @@ ConstantExpr::getFCmp(unsigned short pred, Constant *LHS, Constant *RHS) {
     return FC;          // Fold a few common cases...
 
   // Look up the constant in the table first to ensure uniqueness
-  std::vector<Constant*> ArgVec;
-  ArgVec.push_back(LHS);
-  ArgVec.push_back(RHS);
+  Constant *ArgVec[] = { LHS, RHS };
   // Get the key type with both the opcode and predicate
-  const ExprMapKeyType Key(Instruction::FCmp, ArgVec, pred);
+  const ConstantExprKeyType Key(Instruction::FCmp, ArgVec, pred);
 
   Type *ResultTy = Type::getInt1Ty(LHS->getContext());
   if (VectorType *VT = dyn_cast<VectorType>(LHS->getType()))
@@ -1887,16 +2010,15 @@ ConstantExpr::getFCmp(unsigned short pred, Constant *LHS, Constant *RHS) {
 Constant *ConstantExpr::getExtractElement(Constant *Val, Constant *Idx) {
   assert(Val->getType()->isVectorTy() &&
          "Tried to create extractelement operation on non-vector type!");
-  assert(Idx->getType()->isIntegerTy(32) &&
-         "Extractelement index must be i32 type!");
+  assert(Idx->getType()->isIntegerTy() &&
+         "Extractelement index must be an integer type!");
 
   if (Constant *FC = ConstantFoldExtractElementInstruction(Val, Idx))
     return FC;          // Fold a few common cases.
 
   // Look up the constant in the table first to ensure uniqueness
-  std::vector<Constant*> ArgVec(1, Val);
-  ArgVec.push_back(Idx);
-  const ExprMapKeyType Key(Instruction::ExtractElement,ArgVec);
+  Constant *ArgVec[] = { Val, Idx };
+  const ConstantExprKeyType Key(Instruction::ExtractElement, ArgVec);
 
   LLVMContextImpl *pImpl = Val->getContext().pImpl;
   Type *ReqTy = Val->getType()->getVectorElementType();
@@ -1909,16 +2031,14 @@ Constant *ConstantExpr::getInsertElement(Constant *Val, Constant *Elt,
          "Tried to create insertelement operation on non-vector type!");
   assert(Elt->getType() == Val->getType()->getVectorElementType() &&
          "Insertelement types must match!");
-  assert(Idx->getType()->isIntegerTy(32) &&
+  assert(Idx->getType()->isIntegerTy() &&
          "Insertelement index must be i32 type!");
 
   if (Constant *FC = ConstantFoldInsertElementInstruction(Val, Elt, Idx))
     return FC;          // Fold a few common cases.
   // Look up the constant in the table first to ensure uniqueness
-  std::vector<Constant*> ArgVec(1, Val);
-  ArgVec.push_back(Elt);
-  ArgVec.push_back(Idx);
-  const ExprMapKeyType Key(Instruction::InsertElement,ArgVec);
+  Constant *ArgVec[] = { Val, Elt, Idx };
+  const ConstantExprKeyType Key(Instruction::InsertElement, ArgVec);
 
   LLVMContextImpl *pImpl = Val->getContext().pImpl;
   return pImpl->ExprConstants.getOrCreate(Val->getType(), Key);
@@ -1937,10 +2057,8 @@ Constant *ConstantExpr::getShuffleVector(Constant *V1, Constant *V2,
   Type *ShufTy = VectorType::get(EltTy, NElts);
 
   // Look up the constant in the table first to ensure uniqueness
-  std::vector<Constant*> ArgVec(1, V1);
-  ArgVec.push_back(V2);
-  ArgVec.push_back(Mask);
-  const ExprMapKeyType Key(Instruction::ShuffleVector,ArgVec);
+  Constant *ArgVec[] = { V1, V2, Mask };
+  const ConstantExprKeyType Key(Instruction::ShuffleVector, ArgVec);
 
   LLVMContextImpl *pImpl = ShufTy->getContext().pImpl;
   return pImpl->ExprConstants.getOrCreate(ShufTy, Key);
@@ -1948,14 +2066,22 @@ Constant *ConstantExpr::getShuffleVector(Constant *V1, Constant *V2,
 
 Constant *ConstantExpr::getInsertValue(Constant *Agg, Constant *Val,
                                        ArrayRef<unsigned> Idxs) {
+  assert(Agg->getType()->isFirstClassType() &&
+         "Non-first-class type for constant insertvalue expression");
+
   assert(ExtractValueInst::getIndexedType(Agg->getType(),
                                           Idxs) == Val->getType() &&
          "insertvalue indices invalid!");
-  assert(Agg->getType()->isFirstClassType() &&
-         "Non-first-class type for constant insertvalue expression");
-  Constant *FC = ConstantFoldInsertValueInstruction(Agg, Val, Idxs);
-  assert(FC && "insertvalue constant expr couldn't be folded!");
-  return FC;
+  Type *ReqTy = Val->getType();
+
+  if (Constant *FC = ConstantFoldInsertValueInstruction(Agg, Val, Idxs))
+    return FC;
+
+  Constant *ArgVec[] = { Agg, Val };
+  const ConstantExprKeyType Key(Instruction::InsertValue, ArgVec, 0, 0, Idxs);
+
+  LLVMContextImpl *pImpl = Agg->getContext().pImpl;
+  return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
 }
 
 Constant *ConstantExpr::getExtractValue(Constant *Agg,
@@ -1969,9 +2095,14 @@ Constant *ConstantExpr::getExtractValue(Constant *Agg,
 
   assert(Agg->getType()->isFirstClassType() &&
          "Non-first-class type for constant extractvalue expression");
-  Constant *FC = ConstantFoldExtractValueInstruction(Agg, Idxs);
-  assert(FC && "ExtractValue constant expr couldn't be folded!");
-  return FC;
+  if (Constant *FC = ConstantFoldExtractValueInstruction(Agg, Idxs))
+    return FC;
+
+  Constant *ArgVec[] = { Agg };
+  const ConstantExprKeyType Key(Instruction::ExtractValue, ArgVec, 0, 0, Idxs);
+
+  LLVMContextImpl *pImpl = Agg->getContext().pImpl;
+  return pImpl->ExprConstants.getOrCreate(ReqTy, Key);
 }
 
 Constant *ConstantExpr::getNeg(Constant *C, bool HasNUW, bool HasNSW) {
@@ -2088,7 +2219,7 @@ Constant *ConstantExpr::getBinOpIdentity(unsigned Opcode, Type *Ty) {
   switch (Opcode) {
   default:
     // Doesn't have an identity.
-    return 0;
+    return nullptr;
 
   case Instruction::Add:
   case Instruction::Or:
@@ -2111,7 +2242,7 @@ Constant *ConstantExpr::getBinOpAbsorber(unsigned Opcode, Type *Ty) {
   switch (Opcode) {
   default:
     // Doesn't have an absorber.
-    return 0;
+    return nullptr;
 
   case Instruction::Or:
     return Constant::getAllOnesValue(Ty);
@@ -2228,7 +2359,7 @@ Constant *ConstantDataSequential::getImpl(StringRef Elements, Type *Ty) {
   // of i8, or a 1-element array of i32.  They'll both end up in the same
   /// StringMap bucket, linked up by their Next pointers.  Walk the list.
   ConstantDataSequential **Entry = &Slot.getValue();
-  for (ConstantDataSequential *Node = *Entry; Node != 0;
+  for (ConstantDataSequential *Node = *Entry; Node;
        Entry = &Node->Next, Node = *Entry)
     if (Node->getType() == Ty)
       return Node;
@@ -2255,7 +2386,7 @@ void ConstantDataSequential::destroyConstant() {
   ConstantDataSequential **Entry = &Slot->getValue();
 
   // Remove the entry from the hash table.
-  if ((*Entry)->Next == 0) {
+  if (!(*Entry)->Next) {
     // If there is only one value in the bucket (common case) it must be this
     // entry, and removing the entry should remove the bucket completely.
     assert((*Entry) == this && "Hash mismatch in ConstantDataSequential");
@@ -2276,7 +2407,7 @@ void ConstantDataSequential::destroyConstant() {
 
   // If we were part of a list, make sure that we don't delete the list that is
   // still owned by the uniquing map.
-  Next = 0;
+  Next = nullptr;
 
   // Finally, actually delete it.
   destroyConstantImpl();
@@ -2504,7 +2635,7 @@ Constant *ConstantDataVector::getSplatValue() const {
   unsigned EltSize = getElementByteSize();
   for (unsigned i = 1, e = getNumElements(); i != e; ++i)
     if (memcmp(Base, Base+i*EltSize, EltSize))
-      return 0;
+      return nullptr;
 
   // If they're all the same, return the 0th one as a representative.
   return getElementAsConstant(0);
@@ -2524,6 +2655,17 @@ Constant *ConstantDataVector::getSplatValue() const {
 /// work, but would be really slow because it would have to unique each updated
 /// array instance.
 ///
+void Constant::replaceUsesOfWithOnConstantImpl(Constant *Replacement) {
+  // I do need to replace this with an existing value.
+  assert(Replacement != this && "I didn't contain From!");
+
+  // Everyone using this now uses the replacement.
+  replaceAllUsesWith(Replacement);
+
+  // Delete the old constant!
+  destroyConstant();
+}
+
 void ConstantArray::replaceUsesOfWithOnConstant(Value *From, Value *To,
                                                 Use *U) {
   assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
@@ -2532,8 +2674,6 @@ void ConstantArray::replaceUsesOfWithOnConstant(Value *From, Value *To,
   LLVMContextImpl *pImpl = getType()->getContext().pImpl;
 
   SmallVector<Constant*, 8> Values;
-  LLVMContextImpl::ArrayConstantsTy::LookupKey Lookup;
-  Lookup.first = cast<ArrayType>(getType());
   Values.reserve(getNumOperands());  // Build replacement array.
 
   // Fill values with the modified operands of the constant array.  Also,
@@ -2552,51 +2692,51 @@ void ConstantArray::replaceUsesOfWithOnConstant(Value *From, Value *To,
     AllSame &= Val == ToC;
   }
 
-  Constant *Replacement = 0;
   if (AllSame && ToC->isNullValue()) {
-    Replacement = ConstantAggregateZero::get(getType());
-  } else if (AllSame && isa<UndefValue>(ToC)) {
-    Replacement = UndefValue::get(getType());
-  } else {
-    // Check to see if we have this array type already.
-    Lookup.second = makeArrayRef(Values);
-    LLVMContextImpl::ArrayConstantsTy::MapTy::iterator I =
-      pImpl->ArrayConstants.find(Lookup);
+    replaceUsesOfWithOnConstantImpl(ConstantAggregateZero::get(getType()));
+    return;
+  }
+  if (AllSame && isa<UndefValue>(ToC)) {
+    replaceUsesOfWithOnConstantImpl(UndefValue::get(getType()));
+    return;
+  }
 
-    if (I != pImpl->ArrayConstants.map_end()) {
-      Replacement = I->first;
-    } else {
-      // Okay, the new shape doesn't exist in the system yet.  Instead of
-      // creating a new constant array, inserting it, replaceallusesof'ing the
-      // old with the new, then deleting the old... just update the current one
-      // in place!
-      pImpl->ArrayConstants.remove(this);
-
-      // Update to the new value.  Optimize for the case when we have a single
-      // operand that we're changing, but handle bulk updates efficiently.
-      if (NumUpdated == 1) {
-        unsigned OperandToUpdate = U - OperandList;
-        assert(getOperand(OperandToUpdate) == From &&
-               "ReplaceAllUsesWith broken!");
-        setOperand(OperandToUpdate, ToC);
-      } else {
-        for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
-          if (getOperand(i) == From)
-            setOperand(i, ToC);
-      }
-      pImpl->ArrayConstants.insert(this);
-      return;
-    }
+  // Check for any other type of constant-folding.
+  if (Constant *C = getImpl(getType(), Values)) {
+    replaceUsesOfWithOnConstantImpl(C);
+    return;
   }
 
-  // Otherwise, I do need to replace this with an existing value.
-  assert(Replacement != this && "I didn't contain From!");
+  // Check to see if we have this array type already.
+  LLVMContextImpl::ArrayConstantsTy::LookupKey Lookup(
+    cast<ArrayType>(getType()), makeArrayRef(Values));
+  LLVMContextImpl::ArrayConstantsTy::MapTy::iterator I =
+    pImpl->ArrayConstants.find(Lookup);
 
-  // Everyone using this now uses the replacement.
-  replaceAllUsesWith(Replacement);
+  if (I != pImpl->ArrayConstants.map_end()) {
+    replaceUsesOfWithOnConstantImpl(I->first);
+    return;
+  }
 
-  // Delete the old constant!
-  destroyConstant();
+  // Okay, the new shape doesn't exist in the system yet.  Instead of
+  // creating a new constant array, inserting it, replaceallusesof'ing the
+  // old with the new, then deleting the old... just update the current one
+  // in place!
+  pImpl->ArrayConstants.remove(this);
+
+  // Update to the new value.  Optimize for the case when we have a single
+  // operand that we're changing, but handle bulk updates efficiently.
+  if (NumUpdated == 1) {
+    unsigned OperandToUpdate = U - OperandList;
+    assert(getOperand(OperandToUpdate) == From &&
+           "ReplaceAllUsesWith broken!");
+    setOperand(OperandToUpdate, ToC);
+  } else {
+    for (unsigned I = 0, E = getNumOperands(); I != E; ++I)
+      if (getOperand(I) == From)
+        setOperand(I, ToC);
+  }
+  pImpl->ArrayConstants.insert(this);
 }
 
 void ConstantStruct::replaceUsesOfWithOnConstant(Value *From, Value *To,
@@ -2608,8 +2748,6 @@ void ConstantStruct::replaceUsesOfWithOnConstant(Value *From, Value *To,
   assert(getOperand(OperandToUpdate) == From && "ReplaceAllUsesWith broken!");
 
   SmallVector<Constant*, 8> Values;
-  LLVMContextImpl::StructConstantsTy::LookupKey Lookup;
-  Lookup.first = cast<StructType>(getType());
   Values.reserve(getNumOperands());  // Build replacement struct.
 
   // Fill values with the modified operands of the constant struct.  Also,
@@ -2638,62 +2776,75 @@ void ConstantStruct::replaceUsesOfWithOnConstant(Value *From, Value *To,
 
   LLVMContextImpl *pImpl = getContext().pImpl;
 
-  Constant *Replacement = 0;
   if (isAllZeros) {
-    Replacement = ConstantAggregateZero::get(getType());
-  } else if (isAllUndef) {
-    Replacement = UndefValue::get(getType());
-  } else {
-    // Check to see if we have this struct type already.
-    Lookup.second = makeArrayRef(Values);
-    LLVMContextImpl::StructConstantsTy::MapTy::iterator I =
+    replaceUsesOfWithOnConstantImpl(ConstantAggregateZero::get(getType()));
+    return;
+  }
+  if (isAllUndef) {
+    replaceUsesOfWithOnConstantImpl(UndefValue::get(getType()));
+    return;
+  }
+
+  // Check to see if we have this struct type already.
+  LLVMContextImpl::StructConstantsTy::LookupKey Lookup(
+      cast<StructType>(getType()), makeArrayRef(Values));
+  LLVMContextImpl::StructConstantsTy::MapTy::iterator I =
       pImpl->StructConstants.find(Lookup);
 
-    if (I != pImpl->StructConstants.map_end()) {
-      Replacement = I->first;
-    } else {
-      // Okay, the new shape doesn't exist in the system yet.  Instead of
-      // creating a new constant struct, inserting it, replaceallusesof'ing the
-      // old with the new, then deleting the old... just update the current one
-      // in place!
-      pImpl->StructConstants.remove(this);
-
-      // Update to the new value.
-      setOperand(OperandToUpdate, ToC);
-      pImpl->StructConstants.insert(this);
-      return;
-    }
+  if (I != pImpl->StructConstants.map_end()) {
+    replaceUsesOfWithOnConstantImpl(I->first);
+    return;
   }
 
-  assert(Replacement != this && "I didn't contain From!");
+  // Okay, the new shape doesn't exist in the system yet.  Instead of
+  // creating a new constant struct, inserting it, replaceallusesof'ing the
+  // old with the new, then deleting the old... just update the current one
+  // in place!
+  pImpl->StructConstants.remove(this);
 
-  // Everyone using this now uses the replacement.
-  replaceAllUsesWith(Replacement);
-
-  // Delete the old constant!
-  destroyConstant();
+  // Update to the new value.
+  setOperand(OperandToUpdate, ToC);
+  pImpl->StructConstants.insert(this);
 }
 
 void ConstantVector::replaceUsesOfWithOnConstant(Value *From, Value *To,
                                                  Use *U) {
   assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
+  Constant *ToC = cast<Constant>(To);
 
   SmallVector<Constant*, 8> Values;
   Values.reserve(getNumOperands());  // Build replacement array...
+  unsigned NumUpdated = 0;
   for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
     Constant *Val = getOperand(i);
-    if (Val == From) Val = cast<Constant>(To);
+    if (Val == From) {
+      ++NumUpdated;
+      Val = ToC;
+    }
     Values.push_back(Val);
   }
 
-  Constant *Replacement = get(Values);
-  assert(Replacement != this && "I didn't contain From!");
+  if (Constant *C = getImpl(Values)) {
+    replaceUsesOfWithOnConstantImpl(C);
+    return;
+  }
 
-  // Everyone using this now uses the replacement.
-  replaceAllUsesWith(Replacement);
+  // Update to the new value.  Optimize for the case when we have a single
+  // operand that we're changing, but handle bulk updates efficiently.
+  auto &pImpl = getType()->getContext().pImpl;
+  pImpl->VectorConstants.remove(this);
 
-  // Delete the old constant!
-  destroyConstant();
+  if (NumUpdated == 1) {
+    unsigned OperandToUpdate = U - OperandList;
+    assert(getOperand(OperandToUpdate) == From && "ReplaceAllUsesWith broken!");
+    setOperand(OperandToUpdate, ToC);
+  } else {
+    for (unsigned I = 0, E = getNumOperands(); I != E; ++I)
+      if (getOperand(I) == From)
+        setOperand(I, ToC);
+  }
+
+  pImpl->VectorConstants.insert(this);
 }
 
 void ConstantExpr::replaceUsesOfWithOnConstant(Value *From, Value *ToV,
@@ -2710,6 +2861,25 @@ void ConstantExpr::replaceUsesOfWithOnConstant(Value *From, Value *ToV,
   Constant *Replacement = getWithOperands(NewOps);
   assert(Replacement != this && "I didn't contain From!");
 
+  // Check if Replacement has no users (and is the same type).  Ideally, this
+  // check would be done *before* creating Replacement, but threading this
+  // through constant-folding isn't trivial.
+  if (canBecomeReplacement(Replacement)) {
+    // Avoid unnecessary RAUW traffic.
+    auto &ExprConstants = getType()->getContext().pImpl->ExprConstants;
+    ExprConstants.remove(this);
+
+    auto *CE = cast<ConstantExpr>(Replacement);
+    for (unsigned I = 0, E = getNumOperands(); I != E; ++I)
+      // Only set the operands that have actually changed.
+      if (getOperand(I) != CE->getOperand(I))
+        setOperand(I, CE->getOperand(I));
+
+    CE->destroyConstant();
+    ExprConstants.insert(this);
+    return;
+  }
+
   // Everyone using this now uses the replacement.
   replaceAllUsesWith(Replacement);
 
@@ -2717,6 +2887,31 @@ void ConstantExpr::replaceUsesOfWithOnConstant(Value *From, Value *ToV,
   destroyConstant();
 }
 
+bool ConstantExpr::canBecomeReplacement(const Constant *Replacement) const {
+  // If Replacement already has users, use it regardless.
+  if (!Replacement->use_empty())
+    return false;
+
+  // Check for anything that could have changed during constant-folding.
+  if (getValueID() != Replacement->getValueID())
+    return false;
+  const auto *CE = cast<ConstantExpr>(Replacement);
+  if (getOpcode() != CE->getOpcode())
+    return false;
+  if (getNumOperands() != CE->getNumOperands())
+    return false;
+  if (getRawSubclassOptionalData() != CE->getRawSubclassOptionalData())
+    return false;
+  if (isCompare())
+    if (getPredicate() != CE->getPredicate())
+      return false;
+  if (hasIndices())
+    if (getIndices() != CE->getIndices())
+      return false;
+
+  return true;
+}
+
 Instruction *ConstantExpr::getAsInstruction() {
   SmallVector<Value*,4> ValueOperands;
   for (op_iterator I = op_begin(), E = op_end(); I != E; ++I)
@@ -2737,6 +2932,7 @@ Instruction *ConstantExpr::getAsInstruction() {
   case Instruction::PtrToInt:
   case Instruction::IntToPtr:
   case Instruction::BitCast:
+  case Instruction::AddrSpaceCast:
     return CastInst::Create((Instruction::CastOps)getOpcode(),
                             Ops[0], getType());
   case Instruction::Select: