diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 9657cd28c1f..e9b433b66c3 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -993,18 +993,21 @@ bool ConstantFP::isValueValidForType(Type *Ty, const APFloat& Val) {
 //===----------------------------------------------------------------------===//
 //                      Factory Function Implementation
 
-ConstantAggregateZero* ConstantAggregateZero::get(Type* Ty) {
+ConstantAggregateZero *ConstantAggregateZero::get(Type *Ty) {
   assert((Ty->isStructTy() || Ty->isArrayTy() || Ty->isVectorTy()) &&
          "Cannot create an aggregate zero of non-aggregate type!");
   
-  LLVMContextImpl *pImpl = Ty->getContext().pImpl;
-  return pImpl->AggZeroConstants.getOrCreate(Ty, 0);
+  ConstantAggregateZero *&Entry = Ty->getContext().pImpl->CAZConstants[Ty];
+  if (Entry == 0)
+    Entry = new ConstantAggregateZero(Ty);
+  
+  return Entry;
 }
 
 /// destroyConstant - Remove the constant from the constant table...
 ///
 void ConstantAggregateZero::destroyConstant() {
-  getType()->getContext().pImpl->AggZeroConstants.remove(this);
+  getContext().pImpl->CAZConstants.erase(getType());
   destroyConstantImpl();
 }
 
@@ -1112,13 +1115,18 @@ Constant *ConstantVector::getSplatValue() const {
 //
 
 ConstantPointerNull *ConstantPointerNull::get(PointerType *Ty) {
-  return Ty->getContext().pImpl->NullPtrConstants.getOrCreate(Ty, 0);
+  ConstantPointerNull *&Entry = Ty->getContext().pImpl->CPNConstants[Ty];
+  if (Entry == 0)
+    Entry = new ConstantPointerNull(Ty);
+  
+  return Entry;
 }
 
 // destroyConstant - Remove the constant from the constant table...
 //
 void ConstantPointerNull::destroyConstant() {
-  getType()->getContext().pImpl->NullPtrConstants.remove(this);
+  getContext().pImpl->CPNConstants.erase(getType());
+  // Free the constant and any dangling references to it.
   destroyConstantImpl();
 }
 
@@ -1127,13 +1135,18 @@ void ConstantPointerNull::destroyConstant() {
 //
 
 UndefValue *UndefValue::get(Type *Ty) {
-  return Ty->getContext().pImpl->UndefValueConstants.getOrCreate(Ty, 0);
+  UndefValue *&Entry = Ty->getContext().pImpl->UVConstants[Ty];
+  if (Entry == 0)
+    Entry = new UndefValue(Ty);
+  
+  return Entry;
 }
 
 // destroyConstant - Remove the constant from the constant table.
 //
 void UndefValue::destroyConstant() {
-  getType()->getContext().pImpl->UndefValueConstants.remove(this);
+  // Free the constant and any dangling references to it.
+  getContext().pImpl->UVConstants.erase(getType());
   destroyConstantImpl();
 }
 
diff --git a/lib/VMCore/ConstantsContext.h b/lib/VMCore/ConstantsContext.h
index 4ee4296d448..4bdeaa78302 100644
--- a/lib/VMCore/ConstantsContext.h
+++ b/lib/VMCore/ConstantsContext.h
@@ -477,13 +477,6 @@ struct ConstantKeyData<ConstantExpr> {
   }
 };
 
-// ConstantAggregateZero does not take extra "value" argument...
-template<class ValType>
-struct ConstantCreator<ConstantAggregateZero, Type, ValType> {
-  static ConstantAggregateZero *create(Type *Ty, const ValType &V){
-    return new ConstantAggregateZero(Ty);
-  }
-};
 
 template<>
 struct ConstantKeyData<ConstantVector> {
@@ -497,14 +490,6 @@ struct ConstantKeyData<ConstantVector> {
   }
 };
 
-template<>
-struct ConstantKeyData<ConstantAggregateZero> {
-  typedef char ValType;
-  static ValType getValType(ConstantAggregateZero *C) {
-    return 0;
-  }
-};
-
 template<>
 struct ConstantKeyData<ConstantArray> {
   typedef std::vector<Constant*> ValType;
@@ -529,37 +514,6 @@ struct ConstantKeyData<ConstantStruct> {
   }
 };
 
-// ConstantPointerNull does not take extra "value" argument...
-template<class ValType>
-struct ConstantCreator<ConstantPointerNull, PointerType, ValType> {
-  static ConstantPointerNull *create(PointerType *Ty, const ValType &V){
-    return new ConstantPointerNull(Ty);
-  }
-};
-
-template<>
-struct ConstantKeyData<ConstantPointerNull> {
-  typedef char ValType;
-  static ValType getValType(ConstantPointerNull *C) {
-    return 0;
-  }
-};
-
-// UndefValue does not take extra "value" argument...
-template<class ValType>
-struct ConstantCreator<UndefValue, Type, ValType> {
-  static UndefValue *create(Type *Ty, const ValType &V) {
-    return new UndefValue(Ty);
-  }
-};
-
-template<>
-struct ConstantKeyData<UndefValue> {
-  typedef char ValType;
-  static ValType getValType(UndefValue *C) {
-    return 0;
-  }
-};
 
 template<>
 struct ConstantCreator<InlineAsm, PointerType, InlineAsmKeyType> {
diff --git a/lib/VMCore/LLVMContextImpl.cpp b/lib/VMCore/LLVMContextImpl.cpp
index b0dd680926d..2eaebaceb1d 100644
--- a/lib/VMCore/LLVMContextImpl.cpp
+++ b/lib/VMCore/LLVMContextImpl.cpp
@@ -58,6 +58,8 @@ LLVMContextImpl::~LLVMContextImpl() {
   std::vector<Module*> Modules(OwnedModules.begin(), OwnedModules.end());
   DeleteContainerPointers(Modules);
   
+  // Free the constants.  This is important to do here to ensure that they are
+  // freed before the LeakDetector is torn down.
   std::for_each(ExprConstants.map_begin(), ExprConstants.map_end(),
                 DropReferences());
   std::for_each(ArrayConstants.map_begin(), ArrayConstants.map_end(),
@@ -70,9 +72,9 @@ LLVMContextImpl::~LLVMContextImpl() {
   ArrayConstants.freeConstants();
   StructConstants.freeConstants();
   VectorConstants.freeConstants();
-  AggZeroConstants.freeConstants();
-  NullPtrConstants.freeConstants();
-  UndefValueConstants.freeConstants();
+  DeleteContainerSeconds(CAZConstants);
+  DeleteContainerSeconds(CPNConstants);
+  DeleteContainerSeconds(UVConstants);
   InlineAsms.freeConstants();
   DeleteContainerSeconds(IntConstants);
   DeleteContainerSeconds(FPConstants);
diff --git a/lib/VMCore/LLVMContextImpl.h b/lib/VMCore/LLVMContextImpl.h
index 30f9d469878..f8abdf17e8a 100644
--- a/lib/VMCore/LLVMContextImpl.h
+++ b/lib/VMCore/LLVMContextImpl.h
@@ -138,7 +138,7 @@ public:
   // on Context destruction.
   SmallPtrSet<MDNode*, 1> NonUniquedMDNodes;
   
-  ConstantUniqueMap<char, char, Type, ConstantAggregateZero> AggZeroConstants;
+  DenseMap<Type*, ConstantAggregateZero*> CAZConstants;
 
   typedef ConstantUniqueMap<std::vector<Constant*>, ArrayRef<Constant*>,
     ArrayType, ConstantArray, true /*largekey*/> ArrayConstantsTy;
@@ -152,9 +152,9 @@ public:
                             VectorType, ConstantVector> VectorConstantsTy;
   VectorConstantsTy VectorConstants;
   
-  ConstantUniqueMap<char, char, PointerType, ConstantPointerNull>
-    NullPtrConstants;
-  ConstantUniqueMap<char, char, Type, UndefValue> UndefValueConstants;
+  DenseMap<PointerType*, ConstantPointerNull*> CPNConstants;
+
+  DenseMap<Type*, UndefValue*> UVConstants;
   
   DenseMap<std::pair<Function*, BasicBlock*> , BlockAddress*> BlockAddresses;
   ConstantUniqueMap<ExprMapKeyType, const ExprMapKeyType&, Type, ConstantExpr>