Import LLVM, at r72732.

1 files changed, 2832 insertions, 0 deletions

diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
new file mode 100644
index 0000000..97f3ac9
--- /dev/null
+++ b/lib/VMCore/Constants.cpp
@@ -0,0 +1,2832 @@
+//===-- Constants.cpp - Implement Constant nodes --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the Constant* classes...
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Constants.h"
+#include "ConstantFold.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/GlobalValue.h"
+#include "llvm/Instructions.h"
+#include "llvm/MDNode.h"
+#include "llvm/Module.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+#include <algorithm>
+#include <map>
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+//                              Constant Class
+//===----------------------------------------------------------------------===//
+
+void Constant::destroyConstantImpl() {
+  // When a Constant is destroyed, there may be lingering
+  // references to the constant by other constants in the constant pool.  These
+  // constants are implicitly dependent on the module that is being deleted,
+  // but they don't know that.  Because we only find out when the CPV is
+  // deleted, we must now notify all of our users (that should only be
+  // Constants) that they are, in fact, invalid now and should be deleted.
+  //
+  while (!use_empty()) {
+    Value *V = use_back();
+#ifndef NDEBUG      // Only in -g mode...
+    if (!isa<Constant>(V))
+      DOUT << "While deleting: " << *this
+           << "\n\nUse still stuck around after Def is destroyed: "
+           << *V << "\n\n";
+#endif
+    assert(isa<Constant>(V) && "References remain to Constant being destroyed");
+    Constant *CV = cast<Constant>(V);
+    CV->destroyConstant();
+
+    // The constant should remove itself from our use list...
+    assert((use_empty() || use_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!");
+  // The only thing that could possibly trap are constant exprs.
+  const ConstantExpr *CE = dyn_cast<ConstantExpr>(this);
+  if (!CE) return false;
+  
+  // ConstantExpr traps if any operands can trap. 
+  for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+    if (getOperand(i)->canTrap()) 
+      return true;
+
+  // Otherwise, only specific operations can trap.
+  switch (CE->getOpcode()) {
+  default:
+    return false;
+  case Instruction::UDiv:
+  case Instruction::SDiv:
+  case Instruction::FDiv:
+  case Instruction::URem:
+  case Instruction::SRem:
+  case Instruction::FRem:
+    // Div and rem can trap if the RHS is not known to be non-zero.
+    if (!isa<ConstantInt>(getOperand(1)) || getOperand(1)->isNullValue())
+      return true;
+    return false;
+  }
+}
+
+/// ContainsRelocations - Return true if the constant value contains relocations
+/// which cannot be resolved at compile time. Kind argument is used to filter
+/// only 'interesting' sorts of relocations.
+bool Constant::ContainsRelocations(unsigned Kind) const {
+  if (const GlobalValue* GV = dyn_cast<GlobalValue>(this)) {
+    bool isLocal = GV->hasLocalLinkage();
+    if ((Kind & Reloc::Local) && isLocal) {
+      // Global has local linkage and 'local' kind of relocations are
+      // requested
+      return true;
+    }
+
+    if ((Kind & Reloc::Global) && !isLocal) {
+      // Global has non-local linkage and 'global' kind of relocations are
+      // requested
+      return true;
+    }
+
+    return false;
+  }
+
+  for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+    if (getOperand(i)->ContainsRelocations(Kind))
+      return true;
+
+  return false;
+}
+
+// Static constructor to create a '0' constant of arbitrary type...
+Constant *Constant::getNullValue(const Type *Ty) {
+  static uint64_t zero[2] = {0, 0};
+  switch (Ty->getTypeID()) {
+  case Type::IntegerTyID:
+    return ConstantInt::get(Ty, 0);
+  case Type::FloatTyID:
+    return ConstantFP::get(APFloat(APInt(32, 0)));
+  case Type::DoubleTyID:
+    return ConstantFP::get(APFloat(APInt(64, 0)));
+  case Type::X86_FP80TyID:
+    return ConstantFP::get(APFloat(APInt(80, 2, zero)));
+  case Type::FP128TyID:
+    return ConstantFP::get(APFloat(APInt(128, 2, zero), true));
+  case Type::PPC_FP128TyID:
+    return ConstantFP::get(APFloat(APInt(128, 2, zero)));
+  case Type::PointerTyID:
+    return ConstantPointerNull::get(cast<PointerType>(Ty));
+  case Type::StructTyID:
+  case Type::ArrayTyID:
+  case Type::VectorTyID:
+    return ConstantAggregateZero::get(Ty);
+  default:
+    // Function, Label, or Opaque type?
+    assert(!"Cannot create a null constant of that type!");
+    return 0;
+  }
+}
+
+Constant *Constant::getAllOnesValue(const Type *Ty) {
+  if (const IntegerType* ITy = dyn_cast<IntegerType>(Ty))
+    return ConstantInt::get(APInt::getAllOnesValue(ITy->getBitWidth()));
+  return ConstantVector::getAllOnesValue(cast<VectorType>(Ty));
+}
+
+// Static constructor to create an integral constant with all bits set
+ConstantInt *ConstantInt::getAllOnesValue(const Type *Ty) {
+  if (const IntegerType* ITy = dyn_cast<IntegerType>(Ty))
+    return ConstantInt::get(APInt::getAllOnesValue(ITy->getBitWidth()));
+  return 0;
+}
+
+/// @returns the value for a vector integer constant of the given type that
+/// has all its bits set to true.
+/// @brief Get the all ones value
+ConstantVector *ConstantVector::getAllOnesValue(const VectorType *Ty) {
+  std::vector<Constant*> Elts;
+  Elts.resize(Ty->getNumElements(),
+              ConstantInt::getAllOnesValue(Ty->getElementType()));
+  assert(Elts[0] && "Not a vector integer type!");
+  return cast<ConstantVector>(ConstantVector::get(Elts));
+}
+
+
+/// getVectorElements - This method, which is only valid on constant of vector
+/// type, returns the elements of the vector in the specified smallvector.
+/// This handles breaking down a vector undef into undef elements, etc.  For
+/// constant exprs and other cases we can't handle, we return an empty vector.
+void Constant::getVectorElements(SmallVectorImpl<Constant*> &Elts) const {
+  assert(isa<VectorType>(getType()) && "Not a vector constant!");
+  
+  if (const ConstantVector *CV = dyn_cast<ConstantVector>(this)) {
+    for (unsigned i = 0, e = CV->getNumOperands(); i != e; ++i)
+      Elts.push_back(CV->getOperand(i));
+    return;
+  }
+  
+  const VectorType *VT = cast<VectorType>(getType());
+  if (isa<ConstantAggregateZero>(this)) {
+    Elts.assign(VT->getNumElements(), 
+                Constant::getNullValue(VT->getElementType()));
+    return;
+  }
+  
+  if (isa<UndefValue>(this)) {
+    Elts.assign(VT->getNumElements(), UndefValue::get(VT->getElementType()));
+    return;
+  }
+  
+  // Unknown type, must be constant expr etc.
+}
+
+
+
+//===----------------------------------------------------------------------===//
+//                                ConstantInt
+//===----------------------------------------------------------------------===//
+
+ConstantInt::ConstantInt(const IntegerType *Ty, const APInt& V)
+  : Constant(Ty, ConstantIntVal, 0, 0), Val(V) {
+  assert(V.getBitWidth() == Ty->getBitWidth() && "Invalid constant for type");
+}
+
+ConstantInt *ConstantInt::TheTrueVal = 0;
+ConstantInt *ConstantInt::TheFalseVal = 0;
+
+namespace llvm {
+  void CleanupTrueFalse(void *) {
+    ConstantInt::ResetTrueFalse();
+  }
+}
+
+static ManagedCleanup<llvm::CleanupTrueFalse> TrueFalseCleanup;
+
+ConstantInt *ConstantInt::CreateTrueFalseVals(bool WhichOne) {
+  assert(TheTrueVal == 0 && TheFalseVal == 0);
+  TheTrueVal  = get(Type::Int1Ty, 1);
+  TheFalseVal = get(Type::Int1Ty, 0);
+  
+  // Ensure that llvm_shutdown nulls out TheTrueVal/TheFalseVal.
+  TrueFalseCleanup.Register();
+  
+  return WhichOne ? TheTrueVal : TheFalseVal;
+}
+
+
+namespace {
+  struct DenseMapAPIntKeyInfo {
+    struct KeyTy {
+      APInt val;
+      const Type* type;
+      KeyTy(const APInt& V, const Type* Ty) : val(V), type(Ty) {}
+      KeyTy(const KeyTy& that) : val(that.val), type(that.type) {}
+      bool operator==(const KeyTy& that) const {
+        return type == that.type && this->val == that.val;
+      }
+      bool operator!=(const KeyTy& that) const {
+        return !this->operator==(that);
+      }
+    };
+    static inline KeyTy getEmptyKey() { return KeyTy(APInt(1,0), 0); }
+    static inline KeyTy getTombstoneKey() { return KeyTy(APInt(1,1), 0); }
+    static unsigned getHashValue(const KeyTy &Key) {
+      return DenseMapInfo<void*>::getHashValue(Key.type) ^ 
+        Key.val.getHashValue();
+    }
+    static bool isEqual(const KeyTy &LHS, const KeyTy &RHS) {
+      return LHS == RHS;
+    }
+    static bool isPod() { return false; }
+  };
+}
+
+
+typedef DenseMap<DenseMapAPIntKeyInfo::KeyTy, ConstantInt*, 
+                 DenseMapAPIntKeyInfo> IntMapTy;
+static ManagedStatic<IntMapTy> IntConstants;
+
+ConstantInt *ConstantInt::get(const Type *Ty, uint64_t V, bool isSigned) {
+  const IntegerType *ITy = cast<IntegerType>(Ty);
+  return get(APInt(ITy->getBitWidth(), V, isSigned));
+}
+
+// Get a ConstantInt from an APInt. Note that the value stored in the DenseMap 
+// as the key, is a DenseMapAPIntKeyInfo::KeyTy which has provided the
+// operator== and operator!= to ensure that the DenseMap doesn't attempt to
+// compare APInt's of different widths, which would violate an APInt class
+// invariant which generates an assertion.
+ConstantInt *ConstantInt::get(const APInt& V) {
+  // Get the corresponding integer type for the bit width of the value.
+  const IntegerType *ITy = IntegerType::get(V.getBitWidth());
+  // get an existing value or the insertion position
+  DenseMapAPIntKeyInfo::KeyTy Key(V, ITy);
+  ConstantInt *&Slot = (*IntConstants)[Key]; 
+  // if it exists, return it.
+  if (Slot)
+    return Slot;
+  // otherwise create a new one, insert it, and return it.
+  return Slot = new ConstantInt(ITy, V);
+}
+
+//===----------------------------------------------------------------------===//
+//                                ConstantFP
+//===----------------------------------------------------------------------===//
+
+static const fltSemantics *TypeToFloatSemantics(const Type *Ty) {
+  if (Ty == Type::FloatTy)
+    return &APFloat::IEEEsingle;
+  if (Ty == Type::DoubleTy)
+    return &APFloat::IEEEdouble;
+  if (Ty == Type::X86_FP80Ty)
+    return &APFloat::x87DoubleExtended;
+  else if (Ty == Type::FP128Ty)
+    return &APFloat::IEEEquad;
+  
+  assert(Ty == Type::PPC_FP128Ty && "Unknown FP format");
+  return &APFloat::PPCDoubleDouble;
+}
+
+ConstantFP::ConstantFP(const Type *Ty, const APFloat& V)
+  : Constant(Ty, ConstantFPVal, 0, 0), Val(V) {
+  assert(&V.getSemantics() == TypeToFloatSemantics(Ty) &&
+         "FP type Mismatch");
+}
+
+bool ConstantFP::isNullValue() const {
+  return Val.isZero() && !Val.isNegative();
+}
+
+ConstantFP *ConstantFP::getNegativeZero(const Type *Ty) {
+  APFloat apf = cast <ConstantFP>(Constant::getNullValue(Ty))->getValueAPF();
+  apf.changeSign();
+  return ConstantFP::get(apf);
+}
+
+bool ConstantFP::isExactlyValue(const APFloat& V) const {
+  return Val.bitwiseIsEqual(V);
+}
+
+namespace {
+  struct DenseMapAPFloatKeyInfo {
+    struct KeyTy {
+      APFloat val;
+      KeyTy(const APFloat& V) : val(V){}
+      KeyTy(const KeyTy& that) : val(that.val) {}
+      bool operator==(const KeyTy& that) const {
+        return this->val.bitwiseIsEqual(that.val);
+      }
+      bool operator!=(const KeyTy& that) const {
+        return !this->operator==(that);
+      }
+    };
+    static inline KeyTy getEmptyKey() { 
+      return KeyTy(APFloat(APFloat::Bogus,1));
+    }
+    static inline KeyTy getTombstoneKey() { 
+      return KeyTy(APFloat(APFloat::Bogus,2)); 
+    }
+    static unsigned getHashValue(const KeyTy &Key) {
+      return Key.val.getHashValue();
+    }
+    static bool isEqual(const KeyTy &LHS, const KeyTy &RHS) {
+      return LHS == RHS;
+    }
+    static bool isPod() { return false; }
+  };
+}
+
+//---- ConstantFP::get() implementation...
+//
+typedef DenseMap<DenseMapAPFloatKeyInfo::KeyTy, ConstantFP*, 
+                 DenseMapAPFloatKeyInfo> FPMapTy;
+
+static ManagedStatic<FPMapTy> FPConstants;
+
+ConstantFP *ConstantFP::get(const APFloat &V) {
+  DenseMapAPFloatKeyInfo::KeyTy Key(V);
+  ConstantFP *&Slot = (*FPConstants)[Key];
+  if (Slot) return Slot;
+  
+  const Type *Ty;
+  if (&V.getSemantics() == &APFloat::IEEEsingle)
+    Ty = Type::FloatTy;
+  else if (&V.getSemantics() == &APFloat::IEEEdouble)
+    Ty = Type::DoubleTy;
+  else if (&V.getSemantics() == &APFloat::x87DoubleExtended)
+    Ty = Type::X86_FP80Ty;
+  else if (&V.getSemantics() == &APFloat::IEEEquad)
+    Ty = Type::FP128Ty;
+  else {
+    assert(&V.getSemantics() == &APFloat::PPCDoubleDouble&&"Unknown FP format");
+    Ty = Type::PPC_FP128Ty;
+  }
+  
+  return Slot = new ConstantFP(Ty, V);
+}
+
+/// get() - This returns a constant fp for the specified value in the
+/// specified type.  This should only be used for simple constant values like
+/// 2.0/1.0 etc, that are known-valid both as double and as the target format.
+ConstantFP *ConstantFP::get(const Type *Ty, double V) {
+  APFloat FV(V);
+  bool ignored;
+  FV.convert(*TypeToFloatSemantics(Ty), APFloat::rmNearestTiesToEven, &ignored);
+  return get(FV);
+}
+
+//===----------------------------------------------------------------------===//
+//                            ConstantXXX Classes
+//===----------------------------------------------------------------------===//
+
+
+ConstantArray::ConstantArray(const ArrayType *T,
+                             const std::vector<Constant*> &V)
+  : Constant(T, ConstantArrayVal,
+             OperandTraits<ConstantArray>::op_end(this) - V.size(),
+             V.size()) {
+  assert(V.size() == T->getNumElements() &&
+         "Invalid initializer vector for constant array");
+  Use *OL = OperandList;
+  for (std::vector<Constant*>::const_iterator I = V.begin(), E = V.end();
+       I != E; ++I, ++OL) {
+    Constant *C = *I;
+    assert((C->getType() == T->getElementType() ||
+            (T->isAbstract() &&
+             C->getType()->getTypeID() == T->getElementType()->getTypeID())) &&
+           "Initializer for array element doesn't match array element type!");
+    *OL = C;
+  }
+}
+
+
+ConstantStruct::ConstantStruct(const StructType *T,
+                               const std::vector<Constant*> &V)
+  : Constant(T, ConstantStructVal,
+             OperandTraits<ConstantStruct>::op_end(this) - V.size(),
+             V.size()) {
+  assert(V.size() == T->getNumElements() &&
+         "Invalid initializer vector for constant structure");
+  Use *OL = OperandList;
+  for (std::vector<Constant*>::const_iterator I = V.begin(), E = V.end();
+       I != E; ++I, ++OL) {
+    Constant *C = *I;
+    assert((C->getType() == T->getElementType(I-V.begin()) ||
+            ((T->getElementType(I-V.begin())->isAbstract() ||
+              C->getType()->isAbstract()) &&
+             T->getElementType(I-V.begin())->getTypeID() == 
+                   C->getType()->getTypeID())) &&
+           "Initializer for struct element doesn't match struct element type!");
+    *OL = C;
+  }
+}
+
+
+ConstantVector::ConstantVector(const VectorType *T,
+                               const std::vector<Constant*> &V)
+  : Constant(T, ConstantVectorVal,
+             OperandTraits<ConstantVector>::op_end(this) - V.size(),
+             V.size()) {
+  Use *OL = OperandList;
+    for (std::vector<Constant*>::const_iterator I = V.begin(), E = V.end();
+         I != E; ++I, ++OL) {
+      Constant *C = *I;
+      assert((C->getType() == T->getElementType() ||
+            (T->isAbstract() &&
+             C->getType()->getTypeID() == T->getElementType()->getTypeID())) &&
+           "Initializer for vector element doesn't match vector element type!");
+    *OL = C;
+  }
+}
+
+
+namespace llvm {
+// We declare several classes private to this file, so use an anonymous
+// namespace
+namespace {
+
+/// UnaryConstantExpr - This class is private to Constants.cpp, and is used
+/// behind the scenes to implement unary constant exprs.
+class VISIBILITY_HIDDEN UnaryConstantExpr : public ConstantExpr {
+  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
+public:
+  // allocate space for exactly one operand
+  void *operator new(size_t s) {
+    return User::operator new(s, 1);
+  }
+  UnaryConstantExpr(unsigned Opcode, Constant *C, const Type *Ty)
+    : ConstantExpr(Ty, Opcode, &Op<0>(), 1) {
+    Op<0>() = C;
+  }
+  /// Transparently provide more efficient getOperand methods.
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+};
+
+/// BinaryConstantExpr - This class is private to Constants.cpp, and is used
+/// behind the scenes to implement binary constant exprs.
+class VISIBILITY_HIDDEN BinaryConstantExpr : public ConstantExpr {
+  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
+public:
+  // allocate space for exactly two operands
+  void *operator new(size_t s) {
+    return User::operator new(s, 2);
+  }
+  BinaryConstantExpr(unsigned Opcode, Constant *C1, Constant *C2)
+    : ConstantExpr(C1->getType(), Opcode, &Op<0>(), 2) {
+    Op<0>() = C1;
+    Op<1>() = C2;
+  }
+  /// Transparently provide more efficient getOperand methods.
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+};
+
+/// SelectConstantExpr - This class is private to Constants.cpp, and is used
+/// behind the scenes to implement select constant exprs.
+class VISIBILITY_HIDDEN SelectConstantExpr : public ConstantExpr {
+  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
+public:
+  // allocate space for exactly three operands
+  void *operator new(size_t s) {
+    return User::operator new(s, 3);
+  }
+  SelectConstantExpr(Constant *C1, Constant *C2, Constant *C3)
+    : ConstantExpr(C2->getType(), Instruction::Select, &Op<0>(), 3) {
+    Op<0>() = C1;
+    Op<1>() = C2;
+    Op<2>() = C3;
+  }
+  /// Transparently provide more efficient getOperand methods.
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+};
+
+/// ExtractElementConstantExpr - This class is private to
+/// Constants.cpp, and is used behind the scenes to implement
+/// extractelement constant exprs.
+class VISIBILITY_HIDDEN ExtractElementConstantExpr : public ConstantExpr {
+  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
+public:
+  // allocate space for exactly two operands
+  void *operator new(size_t s) {
+    return User::operator new(s, 2);
+  }
+  ExtractElementConstantExpr(Constant *C1, Constant *C2)
+    : ConstantExpr(cast<VectorType>(C1->getType())->getElementType(), 
+                   Instruction::ExtractElement, &Op<0>(), 2) {
+    Op<0>() = C1;
+    Op<1>() = C2;
+  }
+  /// Transparently provide more efficient getOperand methods.
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+};
+
+/// InsertElementConstantExpr - This class is private to
+/// Constants.cpp, and is used behind the scenes to implement
+/// insertelement constant exprs.
+class VISIBILITY_HIDDEN InsertElementConstantExpr : public ConstantExpr {
+  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
+public:
+  // allocate space for exactly three operands
+  void *operator new(size_t s) {
+    return User::operator new(s, 3);
+  }
+  InsertElementConstantExpr(Constant *C1, Constant *C2, Constant *C3)
+    : ConstantExpr(C1->getType(), Instruction::InsertElement, 
+                   &Op<0>(), 3) {
+    Op<0>() = C1;
+    Op<1>() = C2;
+    Op<2>() = C3;
+  }
+  /// Transparently provide more efficient getOperand methods.
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+};
+
+/// ShuffleVectorConstantExpr - This class is private to
+/// Constants.cpp, and is used behind the scenes to implement
+/// shufflevector constant exprs.
+class VISIBILITY_HIDDEN ShuffleVectorConstantExpr : public ConstantExpr {
+  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
+public:
+  // allocate space for exactly three operands
+  void *operator new(size_t s) {
+    return User::operator new(s, 3);
+  }
+  ShuffleVectorConstantExpr(Constant *C1, Constant *C2, Constant *C3)
+  : ConstantExpr(VectorType::get(
+                   cast<VectorType>(C1->getType())->getElementType(),
+                   cast<VectorType>(C3->getType())->getNumElements()),
+                 Instruction::ShuffleVector, 
+                 &Op<0>(), 3) {
+    Op<0>() = C1;
+    Op<1>() = C2;
+    Op<2>() = C3;
+  }
+  /// Transparently provide more efficient getOperand methods.
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+};
+
+/// ExtractValueConstantExpr - This class is private to
+/// Constants.cpp, and is used behind the scenes to implement
+/// extractvalue constant exprs.
+class VISIBILITY_HIDDEN ExtractValueConstantExpr : public ConstantExpr {
+  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
+public:
+  // allocate space for exactly one operand
+  void *operator new(size_t s) {
+    return User::operator new(s, 1);
+  }
+  ExtractValueConstantExpr(Constant *Agg,
+                           const SmallVector<unsigned, 4> &IdxList,
+                           const Type *DestTy)
+    : ConstantExpr(DestTy, Instruction::ExtractValue, &Op<0>(), 1),
+      Indices(IdxList) {
+    Op<0>() = Agg;
+  }
+
+  /// Indices - These identify which value to extract.
+  const SmallVector<unsigned, 4> Indices;
+
+  /// Transparently provide more efficient getOperand methods.
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+};
+
+/// InsertValueConstantExpr - This class is private to
+/// Constants.cpp, and is used behind the scenes to implement
+/// insertvalue constant exprs.
+class VISIBILITY_HIDDEN InsertValueConstantExpr : public ConstantExpr {
+  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
+public:
+  // allocate space for exactly one operand
+  void *operator new(size_t s) {
+    return User::operator new(s, 2);
+  }
+  InsertValueConstantExpr(Constant *Agg, Constant *Val,
+                          const SmallVector<unsigned, 4> &IdxList,
+                          const Type *DestTy)
+    : ConstantExpr(DestTy, Instruction::InsertValue, &Op<0>(), 2),
+      Indices(IdxList) {
+    Op<0>() = Agg;
+    Op<1>() = Val;
+  }
+
+  /// Indices - These identify the position for the insertion.
+  const SmallVector<unsigned, 4> Indices;
+
+  /// Transparently provide more efficient getOperand methods.
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+};
+
+
+/// GetElementPtrConstantExpr - This class is private to Constants.cpp, and is
+/// used behind the scenes to implement getelementpr constant exprs.
+class VISIBILITY_HIDDEN GetElementPtrConstantExpr : public ConstantExpr {
+  GetElementPtrConstantExpr(Constant *C, const std::vector<Constant*> &IdxList,
+                            const Type *DestTy);
+public:
+  static GetElementPtrConstantExpr *Create(Constant *C,
+                                           const std::vector<Constant*>&IdxList,
+                                           const Type *DestTy) {
+    return new(IdxList.size() + 1)
+      GetElementPtrConstantExpr(C, IdxList, DestTy);
+  }
+  /// Transparently provide more efficient getOperand methods.
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+};
+
+// CompareConstantExpr - This class is private to Constants.cpp, and is used
+// behind the scenes to implement ICmp and FCmp constant expressions. This is
+// needed in order to store the predicate value for these instructions.
+struct VISIBILITY_HIDDEN CompareConstantExpr : public ConstantExpr {
+  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
+  // allocate space for exactly two operands
+  void *operator new(size_t s) {
+    return User::operator new(s, 2);
+  }
+  unsigned short predicate;
+  CompareConstantExpr(const Type *ty, Instruction::OtherOps opc,
+                      unsigned short pred,  Constant* LHS, Constant* RHS)
+    : ConstantExpr(ty, opc, &Op<0>(), 2), predicate(pred) {
+    Op<0>() = LHS;
+    Op<1>() = RHS;
+  }
+  /// Transparently provide more efficient getOperand methods.
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+};
+
+} // end anonymous namespace
+
+template <>
+struct OperandTraits<UnaryConstantExpr> : FixedNumOperandTraits<1> {
+};
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(UnaryConstantExpr, Value)
+
+template <>
+struct OperandTraits<BinaryConstantExpr> : FixedNumOperandTraits<2> {
+};
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(BinaryConstantExpr, Value)
+
+template <>
+struct OperandTraits<SelectConstantExpr> : FixedNumOperandTraits<3> {
+};
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(SelectConstantExpr, Value)
+
+template <>
+struct OperandTraits<ExtractElementConstantExpr> : FixedNumOperandTraits<2> {
+};
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ExtractElementConstantExpr, Value)
+
+template <>
+struct OperandTraits<InsertElementConstantExpr> : FixedNumOperandTraits<3> {
+};
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(InsertElementConstantExpr, Value)
+
+template <>
+struct OperandTraits<ShuffleVectorConstantExpr> : FixedNumOperandTraits<3> {
+};
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ShuffleVectorConstantExpr, Value)
+
+template <>
+struct OperandTraits<ExtractValueConstantExpr> : FixedNumOperandTraits<1> {
+};
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(ExtractValueConstantExpr, Value)
+
+template <>
+struct OperandTraits<InsertValueConstantExpr> : FixedNumOperandTraits<2> {
+};
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(InsertValueConstantExpr, Value)
+
+template <>
+struct OperandTraits<GetElementPtrConstantExpr> : VariadicOperandTraits<1> {
+};
+
+GetElementPtrConstantExpr::GetElementPtrConstantExpr
+  (Constant *C,
+   const std::vector<Constant*> &IdxList,
+   const Type *DestTy)
+    : ConstantExpr(DestTy, Instruction::GetElementPtr,
+                   OperandTraits<GetElementPtrConstantExpr>::op_end(this)
+                   - (IdxList.size()+1),
+                   IdxList.size()+1) {
+  OperandList[0] = C;
+  for (unsigned i = 0, E = IdxList.size(); i != E; ++i)
+    OperandList[i+1] = IdxList[i];
+}
+
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(GetElementPtrConstantExpr, Value)
+
+
+template <>
+struct OperandTraits<CompareConstantExpr> : FixedNumOperandTraits<2> {
+};
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(CompareConstantExpr, Value)
+
+
+} // End llvm namespace
+
+
+// Utility function for determining if a ConstantExpr is a CastOp or not. This
+// can't be inline because we don't want to #include Instruction.h into
+// Constant.h
+bool ConstantExpr::isCast() const {
+  return Instruction::isCast(getOpcode());
+}
+
+bool ConstantExpr::isCompare() const {
+  return getOpcode() == Instruction::ICmp || getOpcode() == Instruction::FCmp ||
+         getOpcode() == Instruction::VICmp || getOpcode() == Instruction::VFCmp;
+}
+
+bool ConstantExpr::hasIndices() const {
+  return getOpcode() == Instruction::ExtractValue ||
+         getOpcode() == Instruction::InsertValue;
+}
+
+const SmallVector<unsigned, 4> &ConstantExpr::getIndices() const {
+  if (const ExtractValueConstantExpr *EVCE =
+        dyn_cast<ExtractValueConstantExpr>(this))
+    return EVCE->Indices;
+
+  return cast<InsertValueConstantExpr>(this)->Indices;
+}
+
+/// ConstantExpr::get* - Return some common constants without having to
+/// specify the full Instruction::OPCODE identifier.
+///
+Constant *ConstantExpr::getNeg(Constant *C) {
+  return get(Instruction::Sub,
+             ConstantExpr::getZeroValueForNegationExpr(C->getType()),
+             C);
+}
+Constant *ConstantExpr::getNot(Constant *C) {
+  assert((isa<IntegerType>(C->getType()) ||
+            cast<VectorType>(C->getType())->getElementType()->isInteger()) &&
+          "Cannot NOT a nonintegral value!");
+  return get(Instruction::Xor, C,
+             Constant::getAllOnesValue(C->getType()));
+}
+Constant *ConstantExpr::getAdd(Constant *C1, Constant *C2) {
+  return get(Instruction::Add, C1, C2);
+}
+Constant *ConstantExpr::getSub(Constant *C1, Constant *C2) {
+  return get(Instruction::Sub, C1, C2);
+}
+Constant *ConstantExpr::getMul(Constant *C1, Constant *C2) {
+  return get(Instruction::Mul, C1, C2);
+}
+Constant *ConstantExpr::getUDiv(Constant *C1, Constant *C2) {
+  return get(Instruction::UDiv, C1, C2);
+}
+Constant *ConstantExpr::getSDiv(Constant *C1, Constant *C2) {
+  return get(Instruction::SDiv, C1, C2);
+}
+Constant *ConstantExpr::getFDiv(Constant *C1, Constant *C2) {
+  return get(Instruction::FDiv, C1, C2);
+}
+Constant *ConstantExpr::getURem(Constant *C1, Constant *C2) {
+  return get(Instruction::URem, C1, C2);
+}
+Constant *ConstantExpr::getSRem(Constant *C1, Constant *C2) {
+  return get(Instruction::SRem, C1, C2);
+}
+Constant *ConstantExpr::getFRem(Constant *C1, Constant *C2) {
+  return get(Instruction::FRem, C1, C2);
+}
+Constant *ConstantExpr::getAnd(Constant *C1, Constant *C2) {
+  return get(Instruction::And, C1, C2);
+}
+Constant *ConstantExpr::getOr(Constant *C1, Constant *C2) {
+  return get(Instruction::Or, C1, C2);
+}
+Constant *ConstantExpr::getXor(Constant *C1, Constant *C2) {
+  return get(Instruction::Xor, C1, C2);
+}
+unsigned ConstantExpr::getPredicate() const {
+  assert(getOpcode() == Instruction::FCmp || 
+         getOpcode() == Instruction::ICmp ||
+         getOpcode() == Instruction::VFCmp ||
+         getOpcode() == Instruction::VICmp);
+  return ((const CompareConstantExpr*)this)->predicate;
+}
+Constant *ConstantExpr::getShl(Constant *C1, Constant *C2) {
+  return get(Instruction::Shl, C1, C2);
+}
+Constant *ConstantExpr::getLShr(Constant *C1, Constant *C2) {
+  return get(Instruction::LShr, C1, C2);
+}
+Constant *ConstantExpr::getAShr(Constant *C1, Constant *C2) {
+  return get(Instruction::AShr, C1, C2);
+}
+
+/// getWithOperandReplaced - Return a constant expression identical to this
+/// one, but with the specified operand set to the specified value.
+Constant *
+ConstantExpr::getWithOperandReplaced(unsigned OpNo, Constant *Op) const {
+  assert(OpNo < getNumOperands() && "Operand num is out of range!");
+  assert(Op->getType() == getOperand(OpNo)->getType() &&
+         "Replacing operand with value of different type!");
+  if (getOperand(OpNo) == Op)
+    return const_cast<ConstantExpr*>(this);
+  
+  Constant *Op0, *Op1, *Op2;
+  switch (getOpcode()) {
+  case Instruction::Trunc:
+  case Instruction::ZExt:
+  case Instruction::SExt:
+  case Instruction::FPTrunc:
+  case Instruction::FPExt:
+  case Instruction::UIToFP:
+  case Instruction::SIToFP:
+  case Instruction::FPToUI:
+  case Instruction::FPToSI:
+  case Instruction::PtrToInt:
+  case Instruction::IntToPtr:
+  case Instruction::BitCast:
+    return ConstantExpr::getCast(getOpcode(), Op, getType());
+  case Instruction::Select:
+    Op0 = (OpNo == 0) ? Op : getOperand(0);
+    Op1 = (OpNo == 1) ? Op : getOperand(1);
+    Op2 = (OpNo == 2) ? Op : getOperand(2);
+    return ConstantExpr::getSelect(Op0, Op1, Op2);
+  case Instruction::InsertElement:
+    Op0 = (OpNo == 0) ? Op : getOperand(0);
+    Op1 = (OpNo == 1) ? Op : getOperand(1);
+    Op2 = (OpNo == 2) ? Op : getOperand(2);
+    return ConstantExpr::getInsertElement(Op0, Op1, Op2);
+  case Instruction::ExtractElement:
+    Op0 = (OpNo == 0) ? Op : getOperand(0);
+    Op1 = (OpNo == 1) ? Op : getOperand(1);
+    return ConstantExpr::getExtractElement(Op0, Op1);
+  case Instruction::ShuffleVector:
+    Op0 = (OpNo == 0) ? Op : getOperand(0);
+    Op1 = (OpNo == 1) ? Op : getOperand(1);
+    Op2 = (OpNo == 2) ? Op : getOperand(2);
+    return ConstantExpr::getShuffleVector(Op0, Op1, Op2);
+  case Instruction::GetElementPtr: {
+    SmallVector<Constant*, 8> Ops;
+    Ops.resize(getNumOperands()-1);
+    for (unsigned i = 1, e = getNumOperands(); i != e; ++i)
+      Ops[i-1] = getOperand(i);
+    if (OpNo == 0)
+      return ConstantExpr::getGetElementPtr(Op, &Ops[0], Ops.size());
+    Ops[OpNo-1] = Op;
+    return ConstantExpr::getGetElementPtr(getOperand(0), &Ops[0], Ops.size());
+  }
+  default:
+    assert(getNumOperands() == 2 && "Must be binary operator?");
+    Op0 = (OpNo == 0) ? Op : getOperand(0);
+    Op1 = (OpNo == 1) ? Op : getOperand(1);
+    return ConstantExpr::get(getOpcode(), Op0, Op1);
+  }
+}
+
+/// getWithOperands - This returns the current constant expression with the
+/// operands replaced with the specified values.  The specified operands must
+/// match count and type with the existing ones.
+Constant *ConstantExpr::
+getWithOperands(Constant* const *Ops, unsigned NumOps) const {
+  assert(NumOps == getNumOperands() && "Operand count mismatch!");
+  bool AnyChange = false;
+  for (unsigned i = 0; i != NumOps; ++i) {
+    assert(Ops[i]->getType() == getOperand(i)->getType() &&
+           "Operand type mismatch!");
+    AnyChange |= Ops[i] != getOperand(i);
+  }
+  if (!AnyChange)  // No operands changed, return self.
+    return const_cast<ConstantExpr*>(this);
+
+  switch (getOpcode()) {
+  case Instruction::Trunc:
+  case Instruction::ZExt:
+  case Instruction::SExt:
+  case Instruction::FPTrunc:
+  case Instruction::FPExt:
+  case Instruction::UIToFP:
+  case Instruction::SIToFP:
+  case Instruction::FPToUI:
+  case Instruction::FPToSI:
+  case Instruction::PtrToInt:
+  case Instruction::IntToPtr:
+  case Instruction::BitCast:
+    return ConstantExpr::getCast(getOpcode(), Ops[0], getType());
+  case Instruction::Select:
+    return ConstantExpr::getSelect(Ops[0], Ops[1], Ops[2]);
+  case Instruction::InsertElement:
+    return ConstantExpr::getInsertElement(Ops[0], Ops[1], Ops[2]);
+  case Instruction::ExtractElement:
+    return ConstantExpr::getExtractElement(Ops[0], Ops[1]);
+  case Instruction::ShuffleVector:
+    return ConstantExpr::getShuffleVector(Ops[0], Ops[1], Ops[2]);
+  case Instruction::GetElementPtr:
+    return ConstantExpr::getGetElementPtr(Ops[0], &Ops[1], NumOps-1);
+  case Instruction::ICmp:
+  case Instruction::FCmp:
+  case Instruction::VICmp:
+  case Instruction::VFCmp:
+    return ConstantExpr::getCompare(getPredicate(), Ops[0], Ops[1]);
+  default:
+    assert(getNumOperands() == 2 && "Must be binary operator?");
+    return ConstantExpr::get(getOpcode(), Ops[0], Ops[1]);
+  }
+}
+
+
+//===----------------------------------------------------------------------===//
+//                      isValueValidForType implementations
+
+bool ConstantInt::isValueValidForType(const Type *Ty, uint64_t Val) {
+  unsigned NumBits = cast<IntegerType>(Ty)->getBitWidth(); // assert okay
+  if (Ty == Type::Int1Ty)
+    return Val == 0 || Val == 1;
+  if (NumBits >= 64)
+    return true; // always true, has to fit in largest type
+  uint64_t Max = (1ll << NumBits) - 1;
+  return Val <= Max;
+}
+
+bool ConstantInt::isValueValidForType(const Type *Ty, int64_t Val) {
+  unsigned NumBits = cast<IntegerType>(Ty)->getBitWidth(); // assert okay
+  if (Ty == Type::Int1Ty)
+    return Val == 0 || Val == 1 || Val == -1;
+  if (NumBits >= 64)
+    return true; // always true, has to fit in largest type
+  int64_t Min = -(1ll << (NumBits-1));
+  int64_t Max = (1ll << (NumBits-1)) - 1;
+  return (Val >= Min && Val <= Max);
+}
+
+bool ConstantFP::isValueValidForType(const Type *Ty, const APFloat& Val) {
+  // convert modifies in place, so make a copy.
+  APFloat Val2 = APFloat(Val);
+  bool losesInfo;
+  switch (Ty->getTypeID()) {
+  default:
+    return false;         // These can't be represented as floating point!
+
+  // FIXME rounding mode needs to be more flexible
+  case Type::FloatTyID: {
+    if (&Val2.getSemantics() == &APFloat::IEEEsingle)
+      return true;
+    Val2.convert(APFloat::IEEEsingle, APFloat::rmNearestTiesToEven, &losesInfo);
+    return !losesInfo;
+  }
+  case Type::DoubleTyID: {
+    if (&Val2.getSemantics() == &APFloat::IEEEsingle ||
+        &Val2.getSemantics() == &APFloat::IEEEdouble)
+      return true;
+    Val2.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, &losesInfo);
+    return !losesInfo;
+  }
+  case Type::X86_FP80TyID:
+    return &Val2.getSemantics() == &APFloat::IEEEsingle || 
+           &Val2.getSemantics() == &APFloat::IEEEdouble ||
+           &Val2.getSemantics() == &APFloat::x87DoubleExtended;
+  case Type::FP128TyID:
+    return &Val2.getSemantics() == &APFloat::IEEEsingle || 
+           &Val2.getSemantics() == &APFloat::IEEEdouble ||
+           &Val2.getSemantics() == &APFloat::IEEEquad;
+  case Type::PPC_FP128TyID:
+    return &Val2.getSemantics() == &APFloat::IEEEsingle || 
+           &Val2.getSemantics() == &APFloat::IEEEdouble ||
+           &Val2.getSemantics() == &APFloat::PPCDoubleDouble;
+  }
+}
+
+//===----------------------------------------------------------------------===//
+//                      Factory Function Implementation
+
+
+// The number of operands for each ConstantCreator::create method is
+// determined by the ConstantTraits template.
+// ConstantCreator - A class that is used to create constants by
+// ValueMap*.  This class should be partially specialized if there is
+// something strange that needs to be done to interface to the ctor for the
+// constant.
+//
+namespace llvm {
+  template<class ValType>
+  struct ConstantTraits;
+
+  template<typename T, typename Alloc>
+  struct VISIBILITY_HIDDEN ConstantTraits< std::vector<T, Alloc> > {
+    static unsigned uses(const std::vector<T, Alloc>& v) {
+      return v.size();
+    }
+  };
+
+  template<class ConstantClass, class TypeClass, class ValType>
+  struct VISIBILITY_HIDDEN ConstantCreator {
+    static ConstantClass *create(const TypeClass *Ty, const ValType &V) {
+      return new(ConstantTraits<ValType>::uses(V)) ConstantClass(Ty, V);
+    }
+  };
+
+  template<class ConstantClass, class TypeClass>
+  struct VISIBILITY_HIDDEN ConvertConstantType {
+    static void convert(ConstantClass *OldC, const TypeClass *NewTy) {
+      assert(0 && "This type cannot be converted!\n");
+      abort();
+    }
+  };
+
+  template<class ValType, class TypeClass, class ConstantClass,
+           bool HasLargeKey = false  /*true for arrays and structs*/ >
+  class VISIBILITY_HIDDEN ValueMap : public AbstractTypeUser {
+  public:
+    typedef std::pair<const Type*, ValType> MapKey;
+    typedef std::map<MapKey, Constant *> MapTy;
+    typedef std::map<Constant*, typename MapTy::iterator> InverseMapTy;
+    typedef std::map<const Type*, typename MapTy::iterator> AbstractTypeMapTy;
+  private:
+    /// Map - This is the main map from the element descriptor to the Constants.
+    /// This is the primary way we avoid creating two of the same shape
+    /// constant.
+    MapTy Map;
+    
+    /// InverseMap - If "HasLargeKey" is true, this contains an inverse mapping
+    /// from the constants to their element in Map.  This is important for
+    /// removal of constants from the array, which would otherwise have to scan
+    /// through the map with very large keys.
+    InverseMapTy InverseMap;
+
+    /// AbstractTypeMap - Map for abstract type constants.
+    ///
+    AbstractTypeMapTy AbstractTypeMap;
+
+  public:
+    typename MapTy::iterator map_end() { return Map.end(); }
+    
+    /// InsertOrGetItem - Return an iterator for the specified element.
+    /// If the element exists in the map, the returned iterator points to the
+    /// entry and Exists=true.  If not, the iterator points to the newly
+    /// inserted entry and returns Exists=false.  Newly inserted entries have
+    /// I->second == 0, and should be filled in.
+    typename MapTy::iterator InsertOrGetItem(std::pair<MapKey, Constant *>
+                                   &InsertVal,
+                                   bool &Exists) {
+      std::pair<typename MapTy::iterator, bool> IP = Map.insert(InsertVal);
+      Exists = !IP.second;
+      return IP.first;
+    }
+    
+private:
+    typename MapTy::iterator FindExistingElement(ConstantClass *CP) {
+      if (HasLargeKey) {
+        typename InverseMapTy::iterator IMI = InverseMap.find(CP);
+        assert(IMI != InverseMap.end() && IMI->second != Map.end() &&
+               IMI->second->second == CP &&
+               "InverseMap corrupt!");
+        return IMI->second;
+      }
+      
+      typename MapTy::iterator I =
+        Map.find(MapKey(static_cast<const TypeClass*>(CP->getRawType()),
+                        getValType(CP)));
+      if (I == Map.end() || I->second != CP) {
+        // FIXME: This should not use a linear scan.  If this gets to be a
+        // performance problem, someone should look at this.
+        for (I = Map.begin(); I != Map.end() && I->second != CP; ++I)
+          /* empty */;
+      }
+      return I;
+    }
+public:
+    
+    /// getOrCreate - Return the specified constant from the map, creating it if
+    /// necessary.
+    ConstantClass *getOrCreate(const TypeClass *Ty, const ValType &V) {
+      MapKey Lookup(Ty, V);
+      typename MapTy::iterator I = Map.find(Lookup);
+      // Is it in the map?      
+      if (I != Map.end())
+        return static_cast<ConstantClass *>(I->second);  
+
+      // If no preexisting value, create one now...
+      ConstantClass *Result =
+        ConstantCreator<ConstantClass,TypeClass,ValType>::create(Ty, V);
+
+      assert(Result->getType() == Ty && "Type specified is not correct!");
+      I = Map.insert(I, std::make_pair(MapKey(Ty, V), Result));
+
+      if (HasLargeKey)  // Remember the reverse mapping if needed.
+        InverseMap.insert(std::make_pair(Result, I));
+      
+      // If the type of the constant is abstract, make sure that an entry exists
+      // for it in the AbstractTypeMap.
+      if (Ty->isAbstract()) {
+        typename AbstractTypeMapTy::iterator TI = AbstractTypeMap.find(Ty);
+
+        if (TI == AbstractTypeMap.end()) {
+          // Add ourselves to the ATU list of the type.
+          cast<DerivedType>(Ty)->addAbstractTypeUser(this);
+
+          AbstractTypeMap.insert(TI, std::make_pair(Ty, I));
+        }
+      }
+      return Result;
+    }
+
+    void remove(ConstantClass *CP) {
+      typename MapTy::iterator I = FindExistingElement(CP);
+      assert(I != Map.end() && "Constant not found in constant table!");
+      assert(I->second == CP && "Didn't find correct element?");
+
+      if (HasLargeKey)  // Remember the reverse mapping if needed.
+        InverseMap.erase(CP);
+      
+      // Now that we found the entry, make sure this isn't the entry that
+      // the AbstractTypeMap points to.
+      const TypeClass *Ty = static_cast<const TypeClass *>(I->first.first);
+      if (Ty->isAbstract()) {
+        assert(AbstractTypeMap.count(Ty) &&
+               "Abstract type not in AbstractTypeMap?");
+        typename MapTy::iterator &ATMEntryIt = AbstractTypeMap[Ty];
+        if (ATMEntryIt == I) {
+          // Yes, we are removing the representative entry for this type.
+          // See if there are any other entries of the same type.
+          typename MapTy::iterator TmpIt = ATMEntryIt;
+
+          // First check the entry before this one...
+          if (TmpIt != Map.begin()) {
+            --TmpIt;
+            if (TmpIt->first.first != Ty) // Not the same type, move back...
+              ++TmpIt;
+          }
+
+          // If we didn't find the same type, try to move forward...
+          if (TmpIt == ATMEntryIt) {
+            ++TmpIt;
+            if (TmpIt == Map.end() || TmpIt->first.first != Ty)
+              --TmpIt;   // No entry afterwards with the same type
+          }
+
+          // If there is another entry in the map of the same abstract type,
+          // update the AbstractTypeMap entry now.
+          if (TmpIt != ATMEntryIt) {
+            ATMEntryIt = TmpIt;
+          } else {
+            // Otherwise, we are removing the last instance of this type
+            // from the table.  Remove from the ATM, and from user list.
+            cast<DerivedType>(Ty)->removeAbstractTypeUser(this);
+            AbstractTypeMap.erase(Ty);
+          }
+        }
+      }
+
+      Map.erase(I);
+    }
+
+    
+    /// MoveConstantToNewSlot - If we are about to change C to be the element
+    /// specified by I, update our internal data structures to reflect this
+    /// fact.
+    void MoveConstantToNewSlot(ConstantClass *C, typename MapTy::iterator I) {
+      // First, remove the old location of the specified constant in the map.
+      typename MapTy::iterator OldI = FindExistingElement(C);
+      assert(OldI != Map.end() && "Constant not found in constant table!");
+      assert(OldI->second == C && "Didn't find correct element?");
+      
+      // If this constant is the representative element for its abstract type,
+      // update the AbstractTypeMap so that the representative element is I.
+      if (C->getType()->isAbstract()) {
+        typename AbstractTypeMapTy::iterator ATI =
+            AbstractTypeMap.find(C->getType());
+        assert(ATI != AbstractTypeMap.end() &&
+               "Abstract type not in AbstractTypeMap?");
+        if (ATI->second == OldI)
+          ATI->second = I;
+      }
+      
+      // Remove the old entry from the map.
+      Map.erase(OldI);
+      
+      // Update the inverse map so that we know that this constant is now
+      // located at descriptor I.
+      if (HasLargeKey) {
+        assert(I->second == C && "Bad inversemap entry!");
+        InverseMap[C] = I;
+      }
+    }
+    
+    void refineAbstractType(const DerivedType *OldTy, const Type *NewTy) {
+      typename AbstractTypeMapTy::iterator I =
+        AbstractTypeMap.find(cast<Type>(OldTy));
+
+      assert(I != AbstractTypeMap.end() &&
+             "Abstract type not in AbstractTypeMap?");
+
+      // Convert a constant at a time until the last one is gone.  The last one
+      // leaving will remove() itself, causing the AbstractTypeMapEntry to be
+      // eliminated eventually.
+      do {
+        ConvertConstantType<ConstantClass,
+                            TypeClass>::convert(
+                                static_cast<ConstantClass *>(I->second->second),
+                                                cast<TypeClass>(NewTy));
+
+        I = AbstractTypeMap.find(cast<Type>(OldTy));
+      } while (I != AbstractTypeMap.end());
+    }
+
+    // If the type became concrete without being refined to any other existing
+    // type, we just remove ourselves from the ATU list.
+    void typeBecameConcrete(const DerivedType *AbsTy) {
+      AbsTy->removeAbstractTypeUser(this);
+    }
+
+    void dump() const {
+      DOUT << "Constant.cpp: ValueMap\n";
+    }
+  };
+}
+
+
+
+//---- ConstantAggregateZero::get() implementation...
+//
+namespace llvm {
+  // ConstantAggregateZero does not take extra "value" argument...
+  template<class ValType>
+  struct ConstantCreator<ConstantAggregateZero, Type, ValType> {
+    static ConstantAggregateZero *create(const Type *Ty, const ValType &V){
+      return new ConstantAggregateZero(Ty);
+    }
+  };
+
+  template<>
+  struct ConvertConstantType<ConstantAggregateZero, Type> {
+    static void convert(ConstantAggregateZero *OldC, const Type *NewTy) {
+      // Make everyone now use a constant of the new type...
+      Constant *New = ConstantAggregateZero::get(NewTy);
+      assert(New != OldC && "Didn't replace constant??");
+      OldC->uncheckedReplaceAllUsesWith(New);
+      OldC->destroyConstant();     // This constant is now dead, destroy it.
+    }
+  };
+}
+
+static ManagedStatic<ValueMap<char, Type, 
+                              ConstantAggregateZero> > AggZeroConstants;
+
+static char getValType(ConstantAggregateZero *CPZ) { return 0; }
+
+ConstantAggregateZero *ConstantAggregateZero::get(const Type *Ty) {
+  assert((isa<StructType>(Ty) || isa<ArrayType>(Ty) || isa<VectorType>(Ty)) &&
+         "Cannot create an aggregate zero of non-aggregate type!");
+  return AggZeroConstants->getOrCreate(Ty, 0);
+}
+
+/// destroyConstant - Remove the constant from the constant table...
+///
+void ConstantAggregateZero::destroyConstant() {
+  AggZeroConstants->remove(this);
+  destroyConstantImpl();
+}
+
+//---- ConstantArray::get() implementation...
+//
+namespace llvm {
+  template<>
+  struct ConvertConstantType<ConstantArray, ArrayType> {
+    static void convert(ConstantArray *OldC, const ArrayType *NewTy) {
+      // Make everyone now use a constant of the new type...
+      std::vector<Constant*> C;
+      for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
+        C.push_back(cast<Constant>(OldC->getOperand(i)));
+      Constant *New = ConstantArray::get(NewTy, C);
+      assert(New != OldC && "Didn't replace constant??");
+      OldC->uncheckedReplaceAllUsesWith(New);
+      OldC->destroyConstant();    // This constant is now dead, destroy it.
+    }
+  };
+}
+
+static std::vector<Constant*> getValType(ConstantArray *CA) {
+  std::vector<Constant*> Elements;
+  Elements.reserve(CA->getNumOperands());
+  for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
+    Elements.push_back(cast<Constant>(CA->getOperand(i)));
+  return Elements;
+}
+
+typedef ValueMap<std::vector<Constant*>, ArrayType, 
+                 ConstantArray, true /*largekey*/> ArrayConstantsTy;
+static ManagedStatic<ArrayConstantsTy> ArrayConstants;
+
+Constant *ConstantArray::get(const ArrayType *Ty,
+                             const std::vector<Constant*> &V) {
+  // If this is an all-zero array, return a ConstantAggregateZero object
+  if (!V.empty()) {
+    Constant *C = V[0];
+    if (!C->isNullValue())
+      return ArrayConstants->getOrCreate(Ty, V);
+    for (unsigned i = 1, e = V.size(); i != e; ++i)
+      if (V[i] != C)
+        return ArrayConstants->getOrCreate(Ty, V);
+  }
+  return ConstantAggregateZero::get(Ty);
+}
+
+/// destroyConstant - Remove the constant from the constant table...
+///
+void ConstantArray::destroyConstant() {
+  ArrayConstants->remove(this);
+  destroyConstantImpl();
+}
+
+/// ConstantArray::get(const string&) - Return an array that is initialized to
+/// contain the specified string.  If length is zero then a null terminator is 
+/// added to the specified string so that it may be used in a natural way. 
+/// Otherwise, the length parameter specifies how much of the string to use 
+/// and it won't be null terminated.
+///
+Constant *ConstantArray::get(const std::string &Str, bool AddNull) {
+  std::vector<Constant*> ElementVals;
+  for (unsigned i = 0; i < Str.length(); ++i)
+    ElementVals.push_back(ConstantInt::get(Type::Int8Ty, Str[i]));
+
+  // Add a null terminator to the string...
+  if (AddNull) {
+    ElementVals.push_back(ConstantInt::get(Type::Int8Ty, 0));
+  }
+
+  ArrayType *ATy = ArrayType::get(Type::Int8Ty, ElementVals.size());
+  return ConstantArray::get(ATy, ElementVals);
+}
+
+/// isString - This method returns true if the array is an array of i8, and 
+/// if the elements of the array are all ConstantInt's.
+bool ConstantArray::isString() const {
+  // Check the element type for i8...
+  if (getType()->getElementType() != Type::Int8Ty)
+    return false;
+  // Check the elements to make sure they are all integers, not constant
+  // expressions.
+  for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+    if (!isa<ConstantInt>(getOperand(i)))
+      return false;
+  return true;
+}
+
+/// isCString - This method returns true if the array is a string (see
+/// isString) and it ends in a null byte \\0 and does not contains any other
+/// null bytes except its terminator.
+bool ConstantArray::isCString() const {
+  // Check the element type for i8...
+  if (getType()->getElementType() != Type::Int8Ty)
+    return false;
+  Constant *Zero = Constant::getNullValue(getOperand(0)->getType());
+  // Last element must be a null.
+  if (getOperand(getNumOperands()-1) != Zero)
+    return false;
+  // Other elements must be non-null integers.
+  for (unsigned i = 0, e = getNumOperands()-1; i != e; ++i) {
+    if (!isa<ConstantInt>(getOperand(i)))
+      return false;
+    if (getOperand(i) == Zero)
+      return false;
+  }
+  return true;
+}
+
+
+/// getAsString - If the sub-element type of this array is i8
+/// then this method converts the array to an std::string and returns it.
+/// Otherwise, it asserts out.
+///
+std::string ConstantArray::getAsString() const {
+  assert(isString() && "Not a string!");
+  std::string Result;
+  Result.reserve(getNumOperands());
+  for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
+    Result.push_back((char)cast<ConstantInt>(getOperand(i))->getZExtValue());
+  return Result;
+}
+
+
+//---- ConstantStruct::get() implementation...
+//
+
+namespace llvm {
+  template<>
+  struct ConvertConstantType<ConstantStruct, StructType> {
+    static void convert(ConstantStruct *OldC, const StructType *NewTy) {
+      // Make everyone now use a constant of the new type...
+      std::vector<Constant*> C;
+      for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
+        C.push_back(cast<Constant>(OldC->getOperand(i)));
+      Constant *New = ConstantStruct::get(NewTy, C);
+      assert(New != OldC && "Didn't replace constant??");
+
+      OldC->uncheckedReplaceAllUsesWith(New);
+      OldC->destroyConstant();    // This constant is now dead, destroy it.
+    }
+  };
+}
+
+typedef ValueMap<std::vector<Constant*>, StructType,
+                 ConstantStruct, true /*largekey*/> StructConstantsTy;
+static ManagedStatic<StructConstantsTy> StructConstants;
+
+static std::vector<Constant*> getValType(ConstantStruct *CS) {
+  std::vector<Constant*> Elements;
+  Elements.reserve(CS->getNumOperands());
+  for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i)
+    Elements.push_back(cast<Constant>(CS->getOperand(i)));
+  return Elements;
+}
+
+Constant *ConstantStruct::get(const StructType *Ty,
+                              const std::vector<Constant*> &V) {
+  // Create a ConstantAggregateZero value if all elements are zeros...
+  for (unsigned i = 0, e = V.size(); i != e; ++i)
+    if (!V[i]->isNullValue())
+      return StructConstants->getOrCreate(Ty, V);
+
+  return ConstantAggregateZero::get(Ty);
+}
+
+Constant *ConstantStruct::get(const std::vector<Constant*> &V, bool packed) {
+  std::vector<const Type*> StructEls;
+  StructEls.reserve(V.size());
+  for (unsigned i = 0, e = V.size(); i != e; ++i)
+    StructEls.push_back(V[i]->getType());
+  return get(StructType::get(StructEls, packed), V);
+}
+
+// destroyConstant - Remove the constant from the constant table...
+//
+void ConstantStruct::destroyConstant() {
+  StructConstants->remove(this);
+  destroyConstantImpl();
+}
+
+//---- ConstantVector::get() implementation...
+//
+namespace llvm {
+  template<>
+  struct ConvertConstantType<ConstantVector, VectorType> {
+    static void convert(ConstantVector *OldC, const VectorType *NewTy) {
+      // Make everyone now use a constant of the new type...
+      std::vector<Constant*> C;
+      for (unsigned i = 0, e = OldC->getNumOperands(); i != e; ++i)
+        C.push_back(cast<Constant>(OldC->getOperand(i)));
+      Constant *New = ConstantVector::get(NewTy, C);
+      assert(New != OldC && "Didn't replace constant??");
+      OldC->uncheckedReplaceAllUsesWith(New);
+      OldC->destroyConstant();    // This constant is now dead, destroy it.
+    }
+  };
+}
+
+static std::vector<Constant*> getValType(ConstantVector *CP) {
+  std::vector<Constant*> Elements;
+  Elements.reserve(CP->getNumOperands());
+  for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i)
+    Elements.push_back(CP->getOperand(i));
+  return Elements;
+}
+
+static ManagedStatic<ValueMap<std::vector<Constant*>, VectorType,
+                              ConstantVector> > VectorConstants;
+
+Constant *ConstantVector::get(const VectorType *Ty,
+                              const std::vector<Constant*> &V) {
+  assert(!V.empty() && "Vectors can't be empty");
+  // If this is an all-undef or alll-zero vector, return a
+  // ConstantAggregateZero or UndefValue.
+  Constant *C = V[0];
+  bool isZero = C->isNullValue();
+  bool isUndef = isa<UndefValue>(C);
+
+  if (isZero || isUndef) {
+    for (unsigned i = 1, e = V.size(); i != e; ++i)
+      if (V[i] != C) {
+        isZero = isUndef = false;
+        break;
+      }
+  }
+  
+  if (isZero)
+    return ConstantAggregateZero::get(Ty);
+  if (isUndef)
+    return UndefValue::get(Ty);
+  return VectorConstants->getOrCreate(Ty, V);
+}
+
+Constant *ConstantVector::get(const std::vector<Constant*> &V) {
+  assert(!V.empty() && "Cannot infer type if V is empty");
+  return get(VectorType::get(V.front()->getType(),V.size()), V);
+}
+
+// destroyConstant - Remove the constant from the constant table...
+//
+void ConstantVector::destroyConstant() {
+  VectorConstants->remove(this);
+  destroyConstantImpl();
+}
+
+/// This function will return true iff every element in this vector constant
+/// is set to all ones.
+/// @returns true iff this constant's emements are all set to all ones.
+/// @brief Determine if the value is all ones.
+bool ConstantVector::isAllOnesValue() const {
+  // Check out first element.
+  const Constant *Elt = getOperand(0);
+  const ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
+  if (!CI || !CI->isAllOnesValue()) return false;
+  // 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 false;
+  }
+  return true;
+}
+
+/// getSplatValue - If this is a splat constant, where all of the
+/// elements have the same value, return that value. Otherwise return null.
+Constant *ConstantVector::getSplatValue() {
+  // Check out first element.
+  Constant *Elt = getOperand(0);
+  // 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 Elt;
+}
+
+//---- ConstantPointerNull::get() implementation...
+//
+
+namespace llvm {
+  // ConstantPointerNull does not take extra "value" argument...
+  template<class ValType>
+  struct ConstantCreator<ConstantPointerNull, PointerType, ValType> {
+    static ConstantPointerNull *create(const PointerType *Ty, const ValType &V){
+      return new ConstantPointerNull(Ty);
+    }
+  };
+
+  template<>
+  struct ConvertConstantType<ConstantPointerNull, PointerType> {
+    static void convert(ConstantPointerNull *OldC, const PointerType *NewTy) {
+      // Make everyone now use a constant of the new type...
+      Constant *New = ConstantPointerNull::get(NewTy);
+      assert(New != OldC && "Didn't replace constant??");
+      OldC->uncheckedReplaceAllUsesWith(New);
+      OldC->destroyConstant();     // This constant is now dead, destroy it.
+    }
+  };
+}
+
+static ManagedStatic<ValueMap<char, PointerType, 
+                              ConstantPointerNull> > NullPtrConstants;
+
+static char getValType(ConstantPointerNull *) {
+  return 0;
+}
+
+
+ConstantPointerNull *ConstantPointerNull::get(const PointerType *Ty) {
+  return NullPtrConstants->getOrCreate(Ty, 0);
+}
+
+// destroyConstant - Remove the constant from the constant table...
+//
+void ConstantPointerNull::destroyConstant() {
+  NullPtrConstants->remove(this);
+  destroyConstantImpl();
+}
+
+
+//---- UndefValue::get() implementation...
+//
+
+namespace llvm {
+  // UndefValue does not take extra "value" argument...
+  template<class ValType>
+  struct ConstantCreator<UndefValue, Type, ValType> {
+    static UndefValue *create(const Type *Ty, const ValType &V) {
+      return new UndefValue(Ty);
+    }
+  };
+
+  template<>
+  struct ConvertConstantType<UndefValue, Type> {
+    static void convert(UndefValue *OldC, const Type *NewTy) {
+      // Make everyone now use a constant of the new type.
+      Constant *New = UndefValue::get(NewTy);
+      assert(New != OldC && "Didn't replace constant??");
+      OldC->uncheckedReplaceAllUsesWith(New);
+      OldC->destroyConstant();     // This constant is now dead, destroy it.
+    }
+  };
+}
+
+static ManagedStatic<ValueMap<char, Type, UndefValue> > UndefValueConstants;
+
+static char getValType(UndefValue *) {
+  return 0;
+}
+
+
+UndefValue *UndefValue::get(const Type *Ty) {
+  return UndefValueConstants->getOrCreate(Ty, 0);
+}
+
+// destroyConstant - Remove the constant from the constant table.
+//
+void UndefValue::destroyConstant() {
+  UndefValueConstants->remove(this);
+  destroyConstantImpl();
+}
+
+//---- MDString::get() implementation
+//
+
+MDString::MDString(const char *begin, const char *end)
+  : Constant(Type::MetadataTy, MDStringVal, 0, 0),
+    StrBegin(begin), StrEnd(end) {}
+
+static ManagedStatic<StringMap<MDString*> > MDStringCache;
+
+MDString *MDString::get(const char *StrBegin, const char *StrEnd) {
+  StringMapEntry<MDString *> &Entry = MDStringCache->GetOrCreateValue(StrBegin,
+                                                                      StrEnd);
+  MDString *&S = Entry.getValue();
+  if (!S) S = new MDString(Entry.getKeyData(),
+                           Entry.getKeyData() + Entry.getKeyLength());
+  return S;
+}
+
+void MDString::destroyConstant() {
+  MDStringCache->erase(MDStringCache->find(StrBegin, StrEnd));
+  destroyConstantImpl();
+}
+
+//---- MDNode::get() implementation
+//
+
+static ManagedStatic<FoldingSet<MDNode> > MDNodeSet;
+
+MDNode::MDNode(Value*const* Vals, unsigned NumVals)
+  : Constant(Type::MetadataTy, MDNodeVal, 0, 0) {
+  for (unsigned i = 0; i != NumVals; ++i)
+    Node.push_back(ElementVH(Vals[i], this));
+}
+
+void MDNode::Profile(FoldingSetNodeID &ID) const {
+  for (const_elem_iterator I = elem_begin(), E = elem_end(); I != E; ++I)
+    ID.AddPointer(*I);
+}
+
+MDNode *MDNode::get(Value*const* Vals, unsigned NumVals) {
+  FoldingSetNodeID ID;
+  for (unsigned i = 0; i != NumVals; ++i)
+    ID.AddPointer(Vals[i]);
+
+  void *InsertPoint;
+  if (MDNode *N = MDNodeSet->FindNodeOrInsertPos(ID, InsertPoint))
+    return N;
+
+  // InsertPoint will have been set by the FindNodeOrInsertPos call.
+  MDNode *N = new(0) MDNode(Vals, NumVals);
+  MDNodeSet->InsertNode(N, InsertPoint);
+  return N;
+}
+
+void MDNode::destroyConstant() {
+  MDNodeSet->RemoveNode(this);
+  destroyConstantImpl();
+}
+
+//---- ConstantExpr::get() implementations...
+//
+
+namespace {
+
+struct ExprMapKeyType {
+  typedef SmallVector<unsigned, 4> IndexList;
+
+  ExprMapKeyType(unsigned opc,
+      const std::vector<Constant*> &ops,
+      unsigned short pred = 0,
+      const IndexList &inds = IndexList())
+        : opcode(opc), predicate(pred), operands(ops), indices(inds) {}
+  uint16_t opcode;
+  uint16_t predicate;
+  std::vector<Constant*> operands;
+  IndexList indices;
+  bool operator==(const ExprMapKeyType& that) const {
+    return this->opcode == that.opcode &&
+           this->predicate == that.predicate &&
+           this->operands == that.operands &&
+           this->indices == that.indices;
+  }
+  bool operator<(const ExprMapKeyType & that) const {
+    return this->opcode < that.opcode ||
+      (this->opcode == that.opcode && this->predicate < that.predicate) ||
+      (this->opcode == that.opcode && this->predicate == that.predicate &&
+       this->operands < that.operands) ||
+      (this->opcode == that.opcode && this->predicate == that.predicate &&
+       this->operands == that.operands && this->indices < that.indices);
+  }
+
+  bool operator!=(const ExprMapKeyType& that) const {
+    return !(*this == that);
+  }
+};
+
+}
+
+namespace llvm {
+  template<>
+  struct ConstantCreator<ConstantExpr, Type, ExprMapKeyType> {
+    static ConstantExpr *create(const Type *Ty, const ExprMapKeyType &V,
+        unsigned short pred = 0) {
+      if (Instruction::isCast(V.opcode))
+        return new UnaryConstantExpr(V.opcode, V.operands[0], Ty);
+      if ((V.opcode >= Instruction::BinaryOpsBegin &&
+           V.opcode < Instruction::BinaryOpsEnd))
+        return new BinaryConstantExpr(V.opcode, V.operands[0], V.operands[1]);
+      if (V.opcode == Instruction::Select)
+        return new SelectConstantExpr(V.operands[0], V.operands[1], 
+                                      V.operands[2]);
+      if (V.opcode == Instruction::ExtractElement)
+        return new ExtractElementConstantExpr(V.operands[0], V.operands[1]);
+      if (V.opcode == Instruction::InsertElement)
+        return new InsertElementConstantExpr(V.operands[0], V.operands[1],
+                                             V.operands[2]);
+      if (V.opcode == Instruction::ShuffleVector)
+        return new ShuffleVectorConstantExpr(V.operands[0], V.operands[1],
+                                             V.operands[2]);
+      if (V.opcode == Instruction::InsertValue)
+        return new InsertValueConstantExpr(V.operands[0], V.operands[1],
+                                           V.indices, Ty);
+      if (V.opcode == Instruction::ExtractValue)
+        return new ExtractValueConstantExpr(V.operands[0], V.indices, Ty);
+      if (V.opcode == Instruction::GetElementPtr) {
+        std::vector<Constant*> IdxList(V.operands.begin()+1, V.operands.end());
+        return GetElementPtrConstantExpr::Create(V.operands[0], IdxList, Ty);
+      }
+
+      // The compare instructions are weird. We have to encode the predicate
+      // value and it is combined with the instruction opcode by multiplying
+      // the opcode by one hundred. We must decode this to get the predicate.
+      if (V.opcode == Instruction::ICmp)
+        return new CompareConstantExpr(Ty, Instruction::ICmp, V.predicate, 
+                                       V.operands[0], V.operands[1]);
+      if (V.opcode == Instruction::FCmp) 
+        return new CompareConstantExpr(Ty, Instruction::FCmp, V.predicate, 
+                                       V.operands[0], V.operands[1]);
+      if (V.opcode == Instruction::VICmp)
+        return new CompareConstantExpr(Ty, Instruction::VICmp, V.predicate, 
+                                       V.operands[0], V.operands[1]);
+      if (V.opcode == Instruction::VFCmp) 
+        return new CompareConstantExpr(Ty, Instruction::VFCmp, V.predicate, 
+                                       V.operands[0], V.operands[1]);
+      assert(0 && "Invalid ConstantExpr!");
+      return 0;
+    }
+  };
+
+  template<>
+  struct ConvertConstantType<ConstantExpr, Type> {
+    static void convert(ConstantExpr *OldC, const Type *NewTy) {
+      Constant *New;
+      switch (OldC->getOpcode()) {
+      case Instruction::Trunc:
+      case Instruction::ZExt:
+      case Instruction::SExt:
+      case Instruction::FPTrunc:
+      case Instruction::FPExt:
+      case Instruction::UIToFP:
+      case Instruction::SIToFP:
+      case Instruction::FPToUI:
+      case Instruction::FPToSI:
+      case Instruction::PtrToInt:
+      case Instruction::IntToPtr:
+      case Instruction::BitCast:
+        New = ConstantExpr::getCast(OldC->getOpcode(), OldC->getOperand(0), 
+                                    NewTy);
+        break;
+      case Instruction::Select:
+        New = ConstantExpr::getSelectTy(NewTy, OldC->getOperand(0),
+                                        OldC->getOperand(1),
+                                        OldC->getOperand(2));
+        break;
+      default:
+        assert(OldC->getOpcode() >= Instruction::BinaryOpsBegin &&
+               OldC->getOpcode() <  Instruction::BinaryOpsEnd);
+        New = ConstantExpr::getTy(NewTy, OldC->getOpcode(), OldC->getOperand(0),
+                                  OldC->getOperand(1));
+        break;
+      case Instruction::GetElementPtr:
+        // Make everyone now use a constant of the new type...
+        std::vector<Value*> Idx(OldC->op_begin()+1, OldC->op_end());
+        New = ConstantExpr::getGetElementPtrTy(NewTy, OldC->getOperand(0),
+                                               &Idx[0], Idx.size());
+        break;
+      }
+
+      assert(New != OldC && "Didn't replace constant??");
+      OldC->uncheckedReplaceAllUsesWith(New);
+      OldC->destroyConstant();    // This constant is now dead, destroy it.
+    }
+  };
+} // end namespace llvm
+
+
+static ExprMapKeyType getValType(ConstantExpr *CE) {
+  std::vector<Constant*> Operands;
+  Operands.reserve(CE->getNumOperands());
+  for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i)
+    Operands.push_back(cast<Constant>(CE->getOperand(i)));
+  return ExprMapKeyType(CE->getOpcode(), Operands, 
+      CE->isCompare() ? CE->getPredicate() : 0,
+      CE->hasIndices() ?
+        CE->getIndices() : SmallVector<unsigned, 4>());
+}
+
+static ManagedStatic<ValueMap<ExprMapKeyType, Type,
+                              ConstantExpr> > ExprConstants;
+
+/// This is a utility function to handle folding of casts and lookup of the
+/// cast in the ExprConstants map. It is used by the various get* methods below.
+static inline Constant *getFoldedCast(
+  Instruction::CastOps opc, Constant *C, const Type *Ty) {
+  assert(Ty->isFirstClassType() && "Cannot cast to an aggregate type!");
+  // Fold a few common cases
+  if (Constant *FC = ConstantFoldCastInstruction(opc, C, Ty))
+    return FC;
+
+  // Look up the constant in the table first to ensure uniqueness
+  std::vector<Constant*> argVec(1, C);
+  ExprMapKeyType Key(opc, argVec);
+  return ExprConstants->getOrCreate(Ty, Key);
+}
+ 
+Constant *ConstantExpr::getCast(unsigned oc, Constant *C, const Type *Ty) {
+  Instruction::CastOps opc = Instruction::CastOps(oc);
+  assert(Instruction::isCast(opc) && "opcode out of range");
+  assert(C && Ty && "Null arguments to getCast");
+  assert(Ty->isFirstClassType() && "Cannot cast to an aggregate type!");
+
+  switch (opc) {
+    default:
+      assert(0 && "Invalid cast opcode");
+      break;
+    case Instruction::Trunc:    return getTrunc(C, Ty);
+    case Instruction::ZExt:     return getZExt(C, Ty);
+    case Instruction::SExt:     return getSExt(C, Ty);
+    case Instruction::FPTrunc:  return getFPTrunc(C, Ty);
+    case Instruction::FPExt:    return getFPExtend(C, Ty);
+    case Instruction::UIToFP:   return getUIToFP(C, Ty);
+    case Instruction::SIToFP:   return getSIToFP(C, Ty);
+    case Instruction::FPToUI:   return getFPToUI(C, Ty);
+    case Instruction::FPToSI:   return getFPToSI(C, Ty);
+    case Instruction::PtrToInt: return getPtrToInt(C, Ty);
+    case Instruction::IntToPtr: return getIntToPtr(C, Ty);
+    case Instruction::BitCast:  return getBitCast(C, Ty);
+  }
+  return 0;
+} 
+
+Constant *ConstantExpr::getZExtOrBitCast(Constant *C, const Type *Ty) {
+  if (C->getType()->getPrimitiveSizeInBits() == Ty->getPrimitiveSizeInBits())
+    return getCast(Instruction::BitCast, C, Ty);
+  return getCast(Instruction::ZExt, C, Ty);
+}
+
+Constant *ConstantExpr::getSExtOrBitCast(Constant *C, const Type *Ty) {
+  if (C->getType()->getPrimitiveSizeInBits() == Ty->getPrimitiveSizeInBits())
+    return getCast(Instruction::BitCast, C, Ty);
+  return getCast(Instruction::SExt, C, Ty);
+}
+
+Constant *ConstantExpr::getTruncOrBitCast(Constant *C, const Type *Ty) {
+  if (C->getType()->getPrimitiveSizeInBits() == Ty->getPrimitiveSizeInBits())
+    return getCast(Instruction::BitCast, C, Ty);
+  return getCast(Instruction::Trunc, C, Ty);
+}
+
+Constant *ConstantExpr::getPointerCast(Constant *S, const Type *Ty) {
+  assert(isa<PointerType>(S->getType()) && "Invalid cast");
+  assert((Ty->isInteger() || isa<PointerType>(Ty)) && "Invalid cast");
+
+  if (Ty->isInteger())
+    return getCast(Instruction::PtrToInt, S, Ty);
+  return getCast(Instruction::BitCast, S, Ty);
+}
+
+Constant *ConstantExpr::getIntegerCast(Constant *C, const Type *Ty, 
+                                       bool isSigned) {
+  assert(C->getType()->isInteger() && Ty->isInteger() && "Invalid cast");
+  unsigned SrcBits = C->getType()->getPrimitiveSizeInBits();
+  unsigned DstBits = Ty->getPrimitiveSizeInBits();
+  Instruction::CastOps opcode =
+    (SrcBits == DstBits ? Instruction::BitCast :
+     (SrcBits > DstBits ? Instruction::Trunc :
+      (isSigned ? Instruction::SExt : Instruction::ZExt)));
+  return getCast(opcode, C, Ty);
+}
+
+Constant *ConstantExpr::getFPCast(Constant *C, const Type *Ty) {
+  assert(C->getType()->isFloatingPoint() && Ty->isFloatingPoint() && 
+         "Invalid cast");
+  unsigned SrcBits = C->getType()->getPrimitiveSizeInBits();
+  unsigned DstBits = Ty->getPrimitiveSizeInBits();
+  if (SrcBits == DstBits)
+    return C; // Avoid a useless cast
+  Instruction::CastOps opcode =
+     (SrcBits > DstBits ? Instruction::FPTrunc : Instruction::FPExt);
+  return getCast(opcode, C, Ty);
+}
+
+Constant *ConstantExpr::getTrunc(Constant *C, const Type *Ty) {
+  assert(C->getType()->isInteger() && "Trunc operand must be integer");
+  assert(Ty->isInteger() && "Trunc produces only integral");
+  assert(C->getType()->getPrimitiveSizeInBits() > Ty->getPrimitiveSizeInBits()&&
+         "SrcTy must be larger than DestTy for Trunc!");
+
+  return getFoldedCast(Instruction::Trunc, C, Ty);
+}
+
+Constant *ConstantExpr::getSExt(Constant *C, const Type *Ty) {
+  assert(C->getType()->isInteger() && "SEXt operand must be integral");
+  assert(Ty->isInteger() && "SExt produces only integer");
+  assert(C->getType()->getPrimitiveSizeInBits() < Ty->getPrimitiveSizeInBits()&&
+         "SrcTy must be smaller than DestTy for SExt!");
+
+  return getFoldedCast(Instruction::SExt, C, Ty);
+}
+
+Constant *ConstantExpr::getZExt(Constant *C, const Type *Ty) {
+  assert(C->getType()->isInteger() && "ZEXt operand must be integral");
+  assert(Ty->isInteger() && "ZExt produces only integer");
+  assert(C->getType()->getPrimitiveSizeInBits() < Ty->getPrimitiveSizeInBits()&&
+         "SrcTy must be smaller than DestTy for ZExt!");
+
+  return getFoldedCast(Instruction::ZExt, C, Ty);
+}
+
+Constant *ConstantExpr::getFPTrunc(Constant *C, const Type *Ty) {
+  assert(C->getType()->isFloatingPoint() && Ty->isFloatingPoint() &&
+         C->getType()->getPrimitiveSizeInBits() > Ty->getPrimitiveSizeInBits()&&
+         "This is an illegal floating point truncation!");
+  return getFoldedCast(Instruction::FPTrunc, C, Ty);
+}
+
+Constant *ConstantExpr::getFPExtend(Constant *C, const Type *Ty) {
+  assert(C->getType()->isFloatingPoint() && Ty->isFloatingPoint() &&
+         C->getType()->getPrimitiveSizeInBits() < Ty->getPrimitiveSizeInBits()&&
+         "This is an illegal floating point extension!");
+  return getFoldedCast(Instruction::FPExt, C, Ty);
+}
+
+Constant *ConstantExpr::getUIToFP(Constant *C, const Type *Ty) {
+#ifndef NDEBUG
+  bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
+  bool toVec = Ty->getTypeID() == Type::VectorTyID;
+#endif
+  assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
+  assert(C->getType()->isIntOrIntVector() && Ty->isFPOrFPVector() &&
+         "This is an illegal uint to floating point cast!");
+  return getFoldedCast(Instruction::UIToFP, C, Ty);
+}
+
+Constant *ConstantExpr::getSIToFP(Constant *C, const Type *Ty) {
+#ifndef NDEBUG
+  bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
+  bool toVec = Ty->getTypeID() == Type::VectorTyID;
+#endif
+  assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
+  assert(C->getType()->isIntOrIntVector() && Ty->isFPOrFPVector() &&
+         "This is an illegal sint to floating point cast!");
+  return getFoldedCast(Instruction::SIToFP, C, Ty);
+}
+
+Constant *ConstantExpr::getFPToUI(Constant *C, const Type *Ty) {
+#ifndef NDEBUG
+  bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
+  bool toVec = Ty->getTypeID() == Type::VectorTyID;
+#endif
+  assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
+  assert(C->getType()->isFPOrFPVector() && Ty->isIntOrIntVector() &&
+         "This is an illegal floating point to uint cast!");
+  return getFoldedCast(Instruction::FPToUI, C, Ty);
+}
+
+Constant *ConstantExpr::getFPToSI(Constant *C, const Type *Ty) {
+#ifndef NDEBUG
+  bool fromVec = C->getType()->getTypeID() == Type::VectorTyID;
+  bool toVec = Ty->getTypeID() == Type::VectorTyID;
+#endif
+  assert((fromVec == toVec) && "Cannot convert from scalar to/from vector");
+  assert(C->getType()->isFPOrFPVector() && Ty->isIntOrIntVector() &&
+         "This is an illegal floating point to sint cast!");
+  return getFoldedCast(Instruction::FPToSI, C, Ty);
+}
+
+Constant *ConstantExpr::getPtrToInt(Constant *C, const Type *DstTy) {
+  assert(isa<PointerType>(C->getType()) && "PtrToInt source must be pointer");
+  assert(DstTy->isInteger() && "PtrToInt destination must be integral");
+  return getFoldedCast(Instruction::PtrToInt, C, DstTy);
+}
+
+Constant *ConstantExpr::getIntToPtr(Constant *C, const Type *DstTy) {
+  assert(C->getType()->isInteger() && "IntToPtr source must be integral");
+  assert(isa<PointerType>(DstTy) && "IntToPtr destination must be a pointer");
+  return getFoldedCast(Instruction::IntToPtr, C, DstTy);
+}
+
+Constant *ConstantExpr::getBitCast(Constant *C, const Type *DstTy) {
+  // BitCast implies a no-op cast of type only. No bits change.  However, you 
+  // can't cast pointers to anything but pointers.
+#ifndef NDEBUG
+  const Type *SrcTy = C->getType();
+  assert((isa<PointerType>(SrcTy) == isa<PointerType>(DstTy)) &&
+         "BitCast cannot cast pointer to non-pointer and vice versa");
+
+  // Now we know we're not dealing with mismatched pointer casts (ptr->nonptr
+  // or nonptr->ptr). For all the other types, the cast is okay if source and 
+  // destination bit widths are identical.
+  unsigned SrcBitSize = SrcTy->getPrimitiveSizeInBits();
+  unsigned DstBitSize = DstTy->getPrimitiveSizeInBits();
+#endif
+  assert(SrcBitSize == DstBitSize && "BitCast requires types of same width");
+  
+  // It is common to ask for a bitcast of a value to its own type, handle this
+  // speedily.
+  if (C->getType() == DstTy) return C;
+  
+  return getFoldedCast(Instruction::BitCast, C, DstTy);
+}
+
+Constant *ConstantExpr::getAlignOf(const Type *Ty) {
+  // alignof is implemented as: (i64) gep ({i8,Ty}*)null, 0, 1
+  const Type *AligningTy = StructType::get(Type::Int8Ty, Ty, NULL);
+  Constant *NullPtr = getNullValue(AligningTy->getPointerTo());
+  Constant *Zero = ConstantInt::get(Type::Int32Ty, 0);
+  Constant *One = ConstantInt::get(Type::Int32Ty, 1);
+  Constant *Indices[2] = { Zero, One };
+  Constant *GEP = getGetElementPtr(NullPtr, Indices, 2);
+  return getCast(Instruction::PtrToInt, GEP, Type::Int32Ty);
+}
+
+Constant *ConstantExpr::getSizeOf(const Type *Ty) {
+  // sizeof is implemented as: (i64) gep (Ty*)null, 1
+  Constant *GEPIdx = ConstantInt::get(Type::Int32Ty, 1);
+  Constant *GEP =
+    getGetElementPtr(getNullValue(PointerType::getUnqual(Ty)), &GEPIdx, 1);
+  return getCast(Instruction::PtrToInt, GEP, Type::Int64Ty);
+}
+
+Constant *ConstantExpr::getTy(const Type *ReqTy, unsigned Opcode,
+                              Constant *C1, Constant *C2) {
+  // Check the operands for consistency first
+  assert(Opcode >= Instruction::BinaryOpsBegin &&
+         Opcode <  Instruction::BinaryOpsEnd   &&
+         "Invalid opcode in binary constant expression");
+  assert(C1->getType() == C2->getType() &&
+         "Operand types in binary constant expression should match");
+
+  if (ReqTy == C1->getType() || ReqTy == Type::Int1Ty)
+    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);
+  return ExprConstants->getOrCreate(ReqTy, Key);
+}
+
+Constant *ConstantExpr::getCompareTy(unsigned short predicate,
+                                     Constant *C1, Constant *C2) {
+  bool isVectorType = C1->getType()->getTypeID() == Type::VectorTyID;
+  switch (predicate) {
+    default: assert(0 && "Invalid CmpInst predicate");
+    case CmpInst::FCMP_FALSE: case CmpInst::FCMP_OEQ: case CmpInst::FCMP_OGT:
+    case CmpInst::FCMP_OGE:   case CmpInst::FCMP_OLT: case CmpInst::FCMP_OLE:
+    case CmpInst::FCMP_ONE:   case CmpInst::FCMP_ORD: case CmpInst::FCMP_UNO:
+    case CmpInst::FCMP_UEQ:   case CmpInst::FCMP_UGT: case CmpInst::FCMP_UGE:
+    case CmpInst::FCMP_ULT:   case CmpInst::FCMP_ULE: case CmpInst::FCMP_UNE:
+    case CmpInst::FCMP_TRUE:
+      return isVectorType ? getVFCmp(predicate, C1, C2) 
+                          : getFCmp(predicate, C1, C2);
+    case CmpInst::ICMP_EQ:  case CmpInst::ICMP_NE:  case CmpInst::ICMP_UGT:
+    case CmpInst::ICMP_UGE: case CmpInst::ICMP_ULT: case CmpInst::ICMP_ULE:
+    case CmpInst::ICMP_SGT: case CmpInst::ICMP_SGE: case CmpInst::ICMP_SLT:
+    case CmpInst::ICMP_SLE:
+      return isVectorType ? getVICmp(predicate, C1, C2)
+                          : getICmp(predicate, C1, C2);
+  }
+}
+
+Constant *ConstantExpr::get(unsigned Opcode, Constant *C1, Constant *C2) {
+#ifndef NDEBUG
+  switch (Opcode) {
+  case Instruction::Add: 
+  case Instruction::Sub:
+  case Instruction::Mul: 
+    assert(C1->getType() == C2->getType() && "Op types should be identical!");
+    assert((C1->getType()->isInteger() || C1->getType()->isFloatingPoint() ||
+            isa<VectorType>(C1->getType())) &&
+           "Tried to create an arithmetic operation on a non-arithmetic type!");
+    break;
+  case Instruction::UDiv: 
+  case Instruction::SDiv: 
+    assert(C1->getType() == C2->getType() && "Op types should be identical!");
+    assert((C1->getType()->isInteger() || (isa<VectorType>(C1->getType()) &&
+      cast<VectorType>(C1->getType())->getElementType()->isInteger())) &&
+           "Tried to create an arithmetic operation on a non-arithmetic type!");
+    break;
+  case Instruction::FDiv:
+    assert(C1->getType() == C2->getType() && "Op types should be identical!");
+    assert((C1->getType()->isFloatingPoint() || (isa<VectorType>(C1->getType())
+      && cast<VectorType>(C1->getType())->getElementType()->isFloatingPoint())) 
+      && "Tried to create an arithmetic operation on a non-arithmetic type!");
+    break;
+  case Instruction::URem: 
+  case Instruction::SRem: 
+    assert(C1->getType() == C2->getType() && "Op types should be identical!");
+    assert((C1->getType()->isInteger() || (isa<VectorType>(C1->getType()) &&
+      cast<VectorType>(C1->getType())->getElementType()->isInteger())) &&
+           "Tried to create an arithmetic operation on a non-arithmetic type!");
+    break;
+  case Instruction::FRem:
+    assert(C1->getType() == C2->getType() && "Op types should be identical!");
+    assert((C1->getType()->isFloatingPoint() || (isa<VectorType>(C1->getType())
+      && cast<VectorType>(C1->getType())->getElementType()->isFloatingPoint())) 
+      && "Tried to create an arithmetic operation on a non-arithmetic type!");
+    break;
+  case Instruction::And:
+  case Instruction::Or:
+  case Instruction::Xor:
+    assert(C1->getType() == C2->getType() && "Op types should be identical!");
+    assert((C1->getType()->isInteger() || isa<VectorType>(C1->getType())) &&
+           "Tried to create a logical operation on a non-integral type!");
+    break;
+  case Instruction::Shl:
+  case Instruction::LShr:
+  case Instruction::AShr:
+    assert(C1->getType() == C2->getType() && "Op types should be identical!");
+    assert(C1->getType()->isIntOrIntVector() &&
+           "Tried to create a shift operation on a non-integer type!");
+    break;
+  default:
+    break;
+  }
+#endif
+
+  return getTy(C1->getType(), Opcode, C1, C2);
+}
+
+Constant *ConstantExpr::getCompare(unsigned short pred, 
+                            Constant *C1, Constant *C2) {
+  assert(C1->getType() == C2->getType() && "Op types should be identical!");
+  return getCompareTy(pred, C1, C2);
+}
+
+Constant *ConstantExpr::getSelectTy(const Type *ReqTy, Constant *C,
+                                    Constant *V1, Constant *V2) {
+  assert(!SelectInst::areInvalidOperands(C, V1, V2)&&"Invalid select operands");
+
+  if (ReqTy == V1->getType())
+    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);
+  return ExprConstants->getOrCreate(ReqTy, Key);
+}
+
+Constant *ConstantExpr::getGetElementPtrTy(const Type *ReqTy, Constant *C,
+                                           Value* const *Idxs,
+                                           unsigned NumIdx) {
+  assert(GetElementPtrInst::getIndexedType(C->getType(), Idxs,
+                                           Idxs+NumIdx) ==
+         cast<PointerType>(ReqTy)->getElementType() &&
+         "GEP indices invalid!");
+
+  if (Constant *FC = ConstantFoldGetElementPtr(C, (Constant**)Idxs, NumIdx))
+    return FC;          // Fold a few common cases...
+
+  assert(isa<PointerType>(C->getType()) &&
+         "Non-pointer type for constant GetElementPtr expression");
+  // Look up the constant in the table first to ensure uniqueness
+  std::vector<Constant*> ArgVec;
+  ArgVec.reserve(NumIdx+1);
+  ArgVec.push_back(C);
+  for (unsigned i = 0; i != NumIdx; ++i)
+    ArgVec.push_back(cast<Constant>(Idxs[i]));
+  const ExprMapKeyType Key(Instruction::GetElementPtr, ArgVec);
+  return ExprConstants->getOrCreate(ReqTy, Key);
+}
+
+Constant *ConstantExpr::getGetElementPtr(Constant *C, Value* const *Idxs,
+                                         unsigned NumIdx) {
+  // Get the result type of the getelementptr!
+  const Type *Ty = 
+    GetElementPtrInst::getIndexedType(C->getType(), Idxs, Idxs+NumIdx);
+  assert(Ty && "GEP indices invalid!");
+  unsigned As = cast<PointerType>(C->getType())->getAddressSpace();
+  return getGetElementPtrTy(PointerType::get(Ty, As), C, Idxs, NumIdx);
+}
+
+Constant *ConstantExpr::getGetElementPtr(Constant *C, Constant* const *Idxs,
+                                         unsigned NumIdx) {
+  return getGetElementPtr(C, (Value* const *)Idxs, NumIdx);
+}
+
+
+Constant *
+ConstantExpr::getICmp(unsigned short pred, Constant* LHS, Constant* RHS) {
+  assert(LHS->getType() == RHS->getType());
+  assert(pred >= ICmpInst::FIRST_ICMP_PREDICATE && 
+         pred <= ICmpInst::LAST_ICMP_PREDICATE && "Invalid ICmp Predicate");
+
+  if (Constant *FC = ConstantFoldCompareInstruction(pred, LHS, 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);
+  // Get the key type with both the opcode and predicate
+  const ExprMapKeyType Key(Instruction::ICmp, ArgVec, pred);
+  return ExprConstants->getOrCreate(Type::Int1Ty, Key);
+}
+
+Constant *
+ConstantExpr::getFCmp(unsigned short pred, Constant* LHS, Constant* RHS) {
+  assert(LHS->getType() == RHS->getType());
+  assert(pred <= FCmpInst::LAST_FCMP_PREDICATE && "Invalid FCmp Predicate");
+
+  if (Constant *FC = ConstantFoldCompareInstruction(pred, LHS, 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);
+  // Get the key type with both the opcode and predicate
+  const ExprMapKeyType Key(Instruction::FCmp, ArgVec, pred);
+  return ExprConstants->getOrCreate(Type::Int1Ty, Key);
+}
+
+Constant *
+ConstantExpr::getVICmp(unsigned short pred, Constant* LHS, Constant* RHS) {
+  assert(isa<VectorType>(LHS->getType()) && LHS->getType() == RHS->getType() &&
+         "Tried to create vicmp operation on non-vector type!");
+  assert(pred >= ICmpInst::FIRST_ICMP_PREDICATE && 
+         pred <= ICmpInst::LAST_ICMP_PREDICATE && "Invalid VICmp Predicate");
+
+  const VectorType *VTy = cast<VectorType>(LHS->getType());
+  const Type *EltTy = VTy->getElementType();
+  unsigned NumElts = VTy->getNumElements();
+
+  // See if we can fold the element-wise comparison of the LHS and RHS.
+  SmallVector<Constant *, 16> LHSElts, RHSElts;
+  LHS->getVectorElements(LHSElts);
+  RHS->getVectorElements(RHSElts);
+                    
+  if (!LHSElts.empty() && !RHSElts.empty()) {
+    SmallVector<Constant *, 16> Elts;
+    for (unsigned i = 0; i != NumElts; ++i) {
+      Constant *FC = ConstantFoldCompareInstruction(pred, LHSElts[i],
+                                                    RHSElts[i]);
+      if (ConstantInt *FCI = dyn_cast_or_null<ConstantInt>(FC)) {
+        if (FCI->getZExtValue())
+          Elts.push_back(ConstantInt::getAllOnesValue(EltTy));
+        else
+          Elts.push_back(ConstantInt::get(EltTy, 0ULL));
+      } else if (FC && isa<UndefValue>(FC)) {
+        Elts.push_back(UndefValue::get(EltTy));
+      } else {
+        break;
+      }
+    }
+    if (Elts.size() == NumElts)
+      return ConstantVector::get(&Elts[0], Elts.size());
+  }
+
+  // Look up the constant in the table first to ensure uniqueness
+  std::vector<Constant*> ArgVec;
+  ArgVec.push_back(LHS);
+  ArgVec.push_back(RHS);
+  // Get the key type with both the opcode and predicate
+  const ExprMapKeyType Key(Instruction::VICmp, ArgVec, pred);
+  return ExprConstants->getOrCreate(LHS->getType(), Key);
+}
+
+Constant *
+ConstantExpr::getVFCmp(unsigned short pred, Constant* LHS, Constant* RHS) {
+  assert(isa<VectorType>(LHS->getType()) &&
+         "Tried to create vfcmp operation on non-vector type!");
+  assert(LHS->getType() == RHS->getType());
+  assert(pred <= FCmpInst::LAST_FCMP_PREDICATE && "Invalid VFCmp Predicate");
+
+  const VectorType *VTy = cast<VectorType>(LHS->getType());
+  unsigned NumElts = VTy->getNumElements();
+  const Type *EltTy = VTy->getElementType();
+  const Type *REltTy = IntegerType::get(EltTy->getPrimitiveSizeInBits());
+  const Type *ResultTy = VectorType::get(REltTy, NumElts);
+
+  // See if we can fold the element-wise comparison of the LHS and RHS.
+  SmallVector<Constant *, 16> LHSElts, RHSElts;
+  LHS->getVectorElements(LHSElts);
+  RHS->getVectorElements(RHSElts);
+  
+  if (!LHSElts.empty() && !RHSElts.empty()) {
+    SmallVector<Constant *, 16> Elts;
+    for (unsigned i = 0; i != NumElts; ++i) {
+      Constant *FC = ConstantFoldCompareInstruction(pred, LHSElts[i],
+                                                    RHSElts[i]);
+      if (ConstantInt *FCI = dyn_cast_or_null<ConstantInt>(FC)) {
+        if (FCI->getZExtValue())
+          Elts.push_back(ConstantInt::getAllOnesValue(REltTy));
+        else
+          Elts.push_back(ConstantInt::get(REltTy, 0ULL));
+      } else if (FC && isa<UndefValue>(FC)) {
+        Elts.push_back(UndefValue::get(REltTy));
+      } else {
+        break;
+      }
+    }
+    if (Elts.size() == NumElts)
+      return ConstantVector::get(&Elts[0], Elts.size());
+  }
+
+  // Look up the constant in the table first to ensure uniqueness
+  std::vector<Constant*> ArgVec;
+  ArgVec.push_back(LHS);
+  ArgVec.push_back(RHS);
+  // Get the key type with both the opcode and predicate
+  const ExprMapKeyType Key(Instruction::VFCmp, ArgVec, pred);
+  return ExprConstants->getOrCreate(ResultTy, Key);
+}
+
+Constant *ConstantExpr::getExtractElementTy(const Type *ReqTy, Constant *Val,
+                                            Constant *Idx) {
+  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);
+  return ExprConstants->getOrCreate(ReqTy, Key);
+}
+
+Constant *ConstantExpr::getExtractElement(Constant *Val, Constant *Idx) {
+  assert(isa<VectorType>(Val->getType()) &&
+         "Tried to create extractelement operation on non-vector type!");
+  assert(Idx->getType() == Type::Int32Ty &&
+         "Extractelement index must be i32 type!");
+  return getExtractElementTy(cast<VectorType>(Val->getType())->getElementType(),
+                             Val, Idx);
+}
+
+Constant *ConstantExpr::getInsertElementTy(const Type *ReqTy, Constant *Val,
+                                           Constant *Elt, Constant *Idx) {
+  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);
+  return ExprConstants->getOrCreate(ReqTy, Key);
+}
+
+Constant *ConstantExpr::getInsertElement(Constant *Val, Constant *Elt, 
+                                         Constant *Idx) {
+  assert(isa<VectorType>(Val->getType()) &&
+         "Tried to create insertelement operation on non-vector type!");
+  assert(Elt->getType() == cast<VectorType>(Val->getType())->getElementType()
+         && "Insertelement types must match!");
+  assert(Idx->getType() == Type::Int32Ty &&
+         "Insertelement index must be i32 type!");
+  return getInsertElementTy(Val->getType(), Val, Elt, Idx);
+}
+
+Constant *ConstantExpr::getShuffleVectorTy(const Type *ReqTy, Constant *V1,
+                                           Constant *V2, Constant *Mask) {
+  if (Constant *FC = ConstantFoldShuffleVectorInstruction(V1, V2, Mask))
+    return FC;          // Fold a few common cases...
+  // 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);
+  return ExprConstants->getOrCreate(ReqTy, Key);
+}
+
+Constant *ConstantExpr::getShuffleVector(Constant *V1, Constant *V2, 
+                                         Constant *Mask) {
+  assert(ShuffleVectorInst::isValidOperands(V1, V2, Mask) &&
+         "Invalid shuffle vector constant expr operands!");
+
+  unsigned NElts = cast<VectorType>(Mask->getType())->getNumElements();
+  const Type *EltTy = cast<VectorType>(V1->getType())->getElementType();
+  const Type *ShufTy = VectorType::get(EltTy, NElts);
+  return getShuffleVectorTy(ShufTy, V1, V2, Mask);
+}
+
+Constant *ConstantExpr::getInsertValueTy(const Type *ReqTy, Constant *Agg,
+                                         Constant *Val,
+                                        const unsigned *Idxs, unsigned NumIdx) {
+  assert(ExtractValueInst::getIndexedType(Agg->getType(), Idxs,
+                                          Idxs+NumIdx) == Val->getType() &&
+         "insertvalue indices invalid!");
+  assert(Agg->getType() == ReqTy &&
+         "insertvalue type invalid!");
+  assert(Agg->getType()->isFirstClassType() &&
+         "Non-first-class type for constant InsertValue expression");
+  Constant *FC = ConstantFoldInsertValueInstruction(Agg, Val, Idxs, NumIdx);
+  assert(FC && "InsertValue constant expr couldn't be folded!");
+  return FC;
+}
+
+Constant *ConstantExpr::getInsertValue(Constant *Agg, Constant *Val,
+                                     const unsigned *IdxList, unsigned NumIdx) {
+  assert(Agg->getType()->isFirstClassType() &&
+         "Tried to create insertelement operation on non-first-class type!");
+
+  const Type *ReqTy = Agg->getType();
+#ifndef NDEBUG
+  const Type *ValTy =
+    ExtractValueInst::getIndexedType(Agg->getType(), IdxList, IdxList+NumIdx);
+#endif
+  assert(ValTy == Val->getType() && "insertvalue indices invalid!");
+  return getInsertValueTy(ReqTy, Agg, Val, IdxList, NumIdx);
+}
+
+Constant *ConstantExpr::getExtractValueTy(const Type *ReqTy, Constant *Agg,
+                                        const unsigned *Idxs, unsigned NumIdx) {
+  assert(ExtractValueInst::getIndexedType(Agg->getType(), Idxs,
+                                          Idxs+NumIdx) == ReqTy &&
+         "extractvalue indices invalid!");
+  assert(Agg->getType()->isFirstClassType() &&
+         "Non-first-class type for constant extractvalue expression");
+  Constant *FC = ConstantFoldExtractValueInstruction(Agg, Idxs, NumIdx);
+  assert(FC && "ExtractValue constant expr couldn't be folded!");
+  return FC;
+}
+
+Constant *ConstantExpr::getExtractValue(Constant *Agg,
+                                     const unsigned *IdxList, unsigned NumIdx) {
+  assert(Agg->getType()->isFirstClassType() &&
+         "Tried to create extractelement operation on non-first-class type!");
+
+  const Type *ReqTy =
+    ExtractValueInst::getIndexedType(Agg->getType(), IdxList, IdxList+NumIdx);
+  assert(ReqTy && "extractvalue indices invalid!");
+  return getExtractValueTy(ReqTy, Agg, IdxList, NumIdx);
+}
+
+Constant *ConstantExpr::getZeroValueForNegationExpr(const Type *Ty) {
+  if (const VectorType *PTy = dyn_cast<VectorType>(Ty))
+    if (PTy->getElementType()->isFloatingPoint()) {
+      std::vector<Constant*> zeros(PTy->getNumElements(),
+                           ConstantFP::getNegativeZero(PTy->getElementType()));
+      return ConstantVector::get(PTy, zeros);
+    }
+
+  if (Ty->isFloatingPoint()) 
+    return ConstantFP::getNegativeZero(Ty);
+
+  return Constant::getNullValue(Ty);
+}
+
+// destroyConstant - Remove the constant from the constant table...
+//
+void ConstantExpr::destroyConstant() {
+  ExprConstants->remove(this);
+  destroyConstantImpl();
+}
+
+const char *ConstantExpr::getOpcodeName() const {
+  return Instruction::getOpcodeName(getOpcode());
+}
+
+//===----------------------------------------------------------------------===//
+//                replaceUsesOfWithOnConstant implementations
+
+/// replaceUsesOfWithOnConstant - Update this constant array to change uses of
+/// 'From' to be uses of 'To'.  This must update the uniquing data structures
+/// etc.
+///
+/// Note that we intentionally replace all uses of From with To here.  Consider
+/// a large array that uses 'From' 1000 times.  By handling this case all here,
+/// ConstantArray::replaceUsesOfWithOnConstant is only invoked once, and that
+/// single invocation handles all 1000 uses.  Handling them one at a time would
+/// work, but would be really slow because it would have to unique each updated
+/// array instance.
+void ConstantArray::replaceUsesOfWithOnConstant(Value *From, Value *To,
+                                                Use *U) {
+  assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
+  Constant *ToC = cast<Constant>(To);
+
+  std::pair<ArrayConstantsTy::MapKey, Constant*> Lookup;
+  Lookup.first.first = getType();
+  Lookup.second = this;
+
+  std::vector<Constant*> &Values = Lookup.first.second;
+  Values.reserve(getNumOperands());  // Build replacement array.
+
+  // Fill values with the modified operands of the constant array.  Also, 
+  // compute whether this turns into an all-zeros array.
+  bool isAllZeros = false;
+  unsigned NumUpdated = 0;
+  if (!ToC->isNullValue()) {
+    for (Use *O = OperandList, *E = OperandList+getNumOperands(); O != E; ++O) {
+      Constant *Val = cast<Constant>(O->get());
+      if (Val == From) {
+        Val = ToC;
+        ++NumUpdated;
+      }
+      Values.push_back(Val);
+    }
+  } else {
+    isAllZeros = true;
+    for (Use *O = OperandList, *E = OperandList+getNumOperands(); O != E; ++O) {
+      Constant *Val = cast<Constant>(O->get());
+      if (Val == From) {
+        Val = ToC;
+        ++NumUpdated;
+      }
+      Values.push_back(Val);
+      if (isAllZeros) isAllZeros = Val->isNullValue();
+    }
+  }
+  
+  Constant *Replacement = 0;
+  if (isAllZeros) {
+    Replacement = ConstantAggregateZero::get(getType());
+  } else {
+    // Check to see if we have this array type already.
+    bool Exists;
+    ArrayConstantsTy::MapTy::iterator I =
+      ArrayConstants->InsertOrGetItem(Lookup, Exists);
+    
+    if (Exists) {
+      Replacement = I->second;
+    } 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!
+      ArrayConstants->MoveConstantToNewSlot(this, I);
+      
+      // 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);
+      }
+      return;
+    }
+  }
+ 
+  // Otherwise, 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.
+  uncheckedReplaceAllUsesWith(Replacement);
+  
+  // Delete the old constant!
+  destroyConstant();
+}
+
+void ConstantStruct::replaceUsesOfWithOnConstant(Value *From, Value *To,
+                                                 Use *U) {
+  assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
+  Constant *ToC = cast<Constant>(To);
+
+  unsigned OperandToUpdate = U-OperandList;
+  assert(getOperand(OperandToUpdate) == From && "ReplaceAllUsesWith broken!");
+
+  std::pair<StructConstantsTy::MapKey, Constant*> Lookup;
+  Lookup.first.first = getType();
+  Lookup.second = this;
+  std::vector<Constant*> &Values = Lookup.first.second;
+  Values.reserve(getNumOperands());  // Build replacement struct.
+  
+  
+  // Fill values with the modified operands of the constant struct.  Also, 
+  // compute whether this turns into an all-zeros struct.
+  bool isAllZeros = false;
+  if (!ToC->isNullValue()) {
+    for (Use *O = OperandList, *E = OperandList+getNumOperands(); O != E; ++O)
+      Values.push_back(cast<Constant>(O->get()));
+  } else {
+    isAllZeros = true;
+    for (Use *O = OperandList, *E = OperandList+getNumOperands(); O != E; ++O) {
+      Constant *Val = cast<Constant>(O->get());
+      Values.push_back(Val);
+      if (isAllZeros) isAllZeros = Val->isNullValue();
+    }
+  }
+  Values[OperandToUpdate] = ToC;
+  
+  Constant *Replacement = 0;
+  if (isAllZeros) {
+    Replacement = ConstantAggregateZero::get(getType());
+  } else {
+    // Check to see if we have this array type already.
+    bool Exists;
+    StructConstantsTy::MapTy::iterator I =
+      StructConstants->InsertOrGetItem(Lookup, Exists);
+    
+    if (Exists) {
+      Replacement = I->second;
+    } 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!
+      StructConstants->MoveConstantToNewSlot(this, I);
+      
+      // Update to the new value.
+      setOperand(OperandToUpdate, ToC);
+      return;
+    }
+  }
+  
+  assert(Replacement != this && "I didn't contain From!");
+  
+  // Everyone using this now uses the replacement.
+  uncheckedReplaceAllUsesWith(Replacement);
+  
+  // Delete the old constant!
+  destroyConstant();
+}
+
+void ConstantVector::replaceUsesOfWithOnConstant(Value *From, Value *To,
+                                                 Use *U) {
+  assert(isa<Constant>(To) && "Cannot make Constant refer to non-constant!");
+  
+  std::vector<Constant*> Values;
+  Values.reserve(getNumOperands());  // Build replacement array...
+  for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
+    Constant *Val = getOperand(i);
+    if (Val == From) Val = cast<Constant>(To);
+    Values.push_back(Val);
+  }
+  
+  Constant *Replacement = ConstantVector::get(getType(), Values);
+  assert(Replacement != this && "I didn't contain From!");
+  
+  // Everyone using this now uses the replacement.
+  uncheckedReplaceAllUsesWith(Replacement);
+  
+  // Delete the old constant!
+  destroyConstant();
+}
+
+void ConstantExpr::replaceUsesOfWithOnConstant(Value *From, Value *ToV,
+                                               Use *U) {
+  assert(isa<Constant>(ToV) && "Cannot make Constant refer to non-constant!");
+  Constant *To = cast<Constant>(ToV);
+  
+  Constant *Replacement = 0;
+  if (getOpcode() == Instruction::GetElementPtr) {
+    SmallVector<Constant*, 8> Indices;
+    Constant *Pointer = getOperand(0);
+    Indices.reserve(getNumOperands()-1);
+    if (Pointer == From) Pointer = To;
+    
+    for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
+      Constant *Val = getOperand(i);
+      if (Val == From) Val = To;
+      Indices.push_back(Val);
+    }
+    Replacement = ConstantExpr::getGetElementPtr(Pointer,
+                                                 &Indices[0], Indices.size());
+  } else if (getOpcode() == Instruction::ExtractValue) {
+    Constant *Agg = getOperand(0);
+    if (Agg == From) Agg = To;
+    
+    const SmallVector<unsigned, 4> &Indices = getIndices();
+    Replacement = ConstantExpr::getExtractValue(Agg,
+                                                &Indices[0], Indices.size());
+  } else if (getOpcode() == Instruction::InsertValue) {
+    Constant *Agg = getOperand(0);
+    Constant *Val = getOperand(1);
+    if (Agg == From) Agg = To;
+    if (Val == From) Val = To;
+    
+    const SmallVector<unsigned, 4> &Indices = getIndices();
+    Replacement = ConstantExpr::getInsertValue(Agg, Val,
+                                               &Indices[0], Indices.size());
+  } else if (isCast()) {
+    assert(getOperand(0) == From && "Cast only has one use!");
+    Replacement = ConstantExpr::getCast(getOpcode(), To, getType());
+  } else if (getOpcode() == Instruction::Select) {
+    Constant *C1 = getOperand(0);
+    Constant *C2 = getOperand(1);
+    Constant *C3 = getOperand(2);
+    if (C1 == From) C1 = To;
+    if (C2 == From) C2 = To;
+    if (C3 == From) C3 = To;
+    Replacement = ConstantExpr::getSelect(C1, C2, C3);
+  } else if (getOpcode() == Instruction::ExtractElement) {
+    Constant *C1 = getOperand(0);
+    Constant *C2 = getOperand(1);
+    if (C1 == From) C1 = To;
+    if (C2 == From) C2 = To;
+    Replacement = ConstantExpr::getExtractElement(C1, C2);
+  } else if (getOpcode() == Instruction::InsertElement) {
+    Constant *C1 = getOperand(0);
+    Constant *C2 = getOperand(1);
+    Constant *C3 = getOperand(1);
+    if (C1 == From) C1 = To;
+    if (C2 == From) C2 = To;
+    if (C3 == From) C3 = To;
+    Replacement = ConstantExpr::getInsertElement(C1, C2, C3);
+  } else if (getOpcode() == Instruction::ShuffleVector) {
+    Constant *C1 = getOperand(0);
+    Constant *C2 = getOperand(1);
+    Constant *C3 = getOperand(2);
+    if (C1 == From) C1 = To;
+    if (C2 == From) C2 = To;
+    if (C3 == From) C3 = To;
+    Replacement = ConstantExpr::getShuffleVector(C1, C2, C3);
+  } else if (isCompare()) {
+    Constant *C1 = getOperand(0);
+    Constant *C2 = getOperand(1);
+    if (C1 == From) C1 = To;
+    if (C2 == From) C2 = To;
+    if (getOpcode() == Instruction::ICmp)
+      Replacement = ConstantExpr::getICmp(getPredicate(), C1, C2);
+    else if (getOpcode() == Instruction::FCmp)
+      Replacement = ConstantExpr::getFCmp(getPredicate(), C1, C2);
+    else if (getOpcode() == Instruction::VICmp)
+      Replacement = ConstantExpr::getVICmp(getPredicate(), C1, C2);
+    else {
+      assert(getOpcode() == Instruction::VFCmp);
+      Replacement = ConstantExpr::getVFCmp(getPredicate(), C1, C2);
+    }
+  } else if (getNumOperands() == 2) {
+    Constant *C1 = getOperand(0);
+    Constant *C2 = getOperand(1);
+    if (C1 == From) C1 = To;
+    if (C2 == From) C2 = To;
+    Replacement = ConstantExpr::get(getOpcode(), C1, C2);
+  } else {
+    assert(0 && "Unknown ConstantExpr type!");
+    return;
+  }
+  
+  assert(Replacement != this && "I didn't contain From!");
+  
+  // Everyone using this now uses the replacement.
+  uncheckedReplaceAllUsesWith(Replacement);
+  
+  // Delete the old constant!
+  destroyConstant();
+}
+
+void MDNode::replaceElement(Value *From, Value *To) {
+  SmallVector<Value*, 4> Values;
+  Values.reserve(getNumElements());  // Build replacement array...
+  for (unsigned i = 0, e = getNumElements(); i != e; ++i) {
+    Value *Val = getElement(i);
+    if (Val == From) Val = To;
+    Values.push_back(Val);
+  }
+
+  MDNode *Replacement = MDNode::get(&Values[0], Values.size());
+  assert(Replacement != this && "I didn't contain From!");
+
+  uncheckedReplaceAllUsesWith(Replacement);
+
+  destroyConstant();
+}