diff --git a/llvm/lib/VMCore/Constants.cpp b/llvm/lib/VMCore/Constants.cpp
index 529c45557bc1..02c33528ecfb 100644
--- a/llvm/lib/VMCore/Constants.cpp
+++ b/llvm/lib/VMCore/Constants.cpp
@@ -232,7 +232,6 @@ ConstantInt::ConstantInt(const IntegerType *Ty, const APInt& V)
 
 ConstantInt* ConstantInt::getTrue(LLVMContext &Context) {
   LLVMContextImpl *pImpl = Context.pImpl;
-  sys::SmartScopedWriter<true>(pImpl->ConstantsLock);
   if (pImpl->TheTrueVal)
     return pImpl->TheTrueVal;
   else
@@ -242,7 +241,6 @@ ConstantInt* ConstantInt::getTrue(LLVMContext &Context) {
 
 ConstantInt* ConstantInt::getFalse(LLVMContext &Context) {
   LLVMContextImpl *pImpl = Context.pImpl;
-  sys::SmartScopedWriter<true>(pImpl->ConstantsLock);
   if (pImpl->TheFalseVal)
     return pImpl->TheFalseVal;
   else
@@ -261,22 +259,9 @@ ConstantInt *ConstantInt::get(LLVMContext &Context, const APInt& V) {
   const IntegerType *ITy = IntegerType::get(Context, V.getBitWidth());
   // get an existing value or the insertion position
   DenseMapAPIntKeyInfo::KeyTy Key(V, ITy);
-  
-  Context.pImpl->ConstantsLock.reader_acquire();
   ConstantInt *&Slot = Context.pImpl->IntConstants[Key]; 
-  Context.pImpl->ConstantsLock.reader_release();
-    
-  if (!Slot) {
-    sys::SmartScopedWriter<true> Writer(Context.pImpl->ConstantsLock);
-    ConstantInt *&NewSlot = Context.pImpl->IntConstants[Key]; 
-    if (!Slot) {
-      NewSlot = new ConstantInt(ITy, V);
-    }
-    
-    return NewSlot;
-  } else {
-    return Slot;
-  }
+  if (!Slot) Slot = new ConstantInt(ITy, V);
+  return Slot;
 }
 
 Constant* ConstantInt::get(const Type* Ty, uint64_t V, bool isSigned) {
@@ -405,32 +390,24 @@ ConstantFP* ConstantFP::get(LLVMContext &Context, const APFloat& V) {
   
   LLVMContextImpl* pImpl = Context.pImpl;
   
-  pImpl->ConstantsLock.reader_acquire();
   ConstantFP *&Slot = pImpl->FPConstants[Key];
-  pImpl->ConstantsLock.reader_release();
     
   if (!Slot) {
-    sys::SmartScopedWriter<true> Writer(pImpl->ConstantsLock);
-    ConstantFP *&NewSlot = pImpl->FPConstants[Key];
-    if (!NewSlot) {
-      const Type *Ty;
-      if (&V.getSemantics() == &APFloat::IEEEsingle)
-        Ty = Type::getFloatTy(Context);
-      else if (&V.getSemantics() == &APFloat::IEEEdouble)
-        Ty = Type::getDoubleTy(Context);
-      else if (&V.getSemantics() == &APFloat::x87DoubleExtended)
-        Ty = Type::getX86_FP80Ty(Context);
-      else if (&V.getSemantics() == &APFloat::IEEEquad)
-        Ty = Type::getFP128Ty(Context);
-      else {
-        assert(&V.getSemantics() == &APFloat::PPCDoubleDouble && 
-               "Unknown FP format");
-        Ty = Type::getPPC_FP128Ty(Context);
-      }
-      NewSlot = new ConstantFP(Ty, V);
+    const Type *Ty;
+    if (&V.getSemantics() == &APFloat::IEEEsingle)
+      Ty = Type::getFloatTy(Context);
+    else if (&V.getSemantics() == &APFloat::IEEEdouble)
+      Ty = Type::getDoubleTy(Context);
+    else if (&V.getSemantics() == &APFloat::x87DoubleExtended)
+      Ty = Type::getX86_FP80Ty(Context);
+    else if (&V.getSemantics() == &APFloat::IEEEquad)
+      Ty = Type::getFP128Ty(Context);
+    else {
+      assert(&V.getSemantics() == &APFloat::PPCDoubleDouble && 
+             "Unknown FP format");
+      Ty = Type::getPPC_FP128Ty(Context);
     }
-    
-    return NewSlot;
+    Slot = new ConstantFP(Ty, V);
   }
   
   return Slot;
@@ -1908,7 +1885,6 @@ void ConstantArray::replaceUsesOfWithOnConstant(Value *From, Value *To,
     Replacement = ConstantAggregateZero::get(getType());
   } else {
     // Check to see if we have this array type already.
-    sys::SmartScopedWriter<true> Writer(pImpl->ConstantsLock);
     bool Exists;
     LLVMContextImpl::ArrayConstantsTy::MapTy::iterator I =
       pImpl->ArrayConstants.InsertOrGetItem(Lookup, Exists);
@@ -1987,7 +1963,6 @@ void ConstantStruct::replaceUsesOfWithOnConstant(Value *From, Value *To,
     Replacement = ConstantAggregateZero::get(getType());
   } else {
     // Check to see if we have this array type already.
-    sys::SmartScopedWriter<true> Writer(pImpl->ConstantsLock);
     bool Exists;
     LLVMContextImpl::StructConstantsTy::MapTy::iterator I =
       pImpl->StructConstants.InsertOrGetItem(Lookup, Exists);
diff --git a/llvm/lib/VMCore/LLVMContextImpl.h b/llvm/lib/VMCore/LLVMContextImpl.h
index 83888c3907bf..58e8870d24e5 100644
--- a/llvm/lib/VMCore/LLVMContextImpl.h
+++ b/llvm/lib/VMCore/LLVMContextImpl.h
@@ -96,7 +96,6 @@ struct DenseMapAPFloatKeyInfo {
 
 class LLVMContextImpl {
 public:
-  sys::SmartRWMutex<true> ConstantsLock;
   typedef DenseMap<DenseMapAPIntKeyInfo::KeyTy, ConstantInt*, 
                          DenseMapAPIntKeyInfo> IntMapTy;
   IntMapTy IntConstants;
diff --git a/llvm/lib/VMCore/Metadata.cpp b/llvm/lib/VMCore/Metadata.cpp
index 0528e48259e7..0434c6dd2a19 100644
--- a/llvm/lib/VMCore/Metadata.cpp
+++ b/llvm/lib/VMCore/Metadata.cpp
@@ -52,7 +52,6 @@ void MetadataBase::resizeOperands(unsigned NumOps) {
 //
 MDString *MDString::get(LLVMContext &Context, const StringRef &Str) {
   LLVMContextImpl *pImpl = Context.pImpl;
-  sys::SmartScopedWriter<true> Writer(pImpl->ConstantsLock);
   StringMapEntry<MDString *> &Entry = 
     pImpl->MDStringCache.GetOrCreateValue(Str);
   MDString *&S = Entry.getValue();
@@ -93,12 +92,10 @@ MDNode *MDNode::get(LLVMContext &Context, Value*const* Vals, unsigned NumVals) {
   void *InsertPoint;
   MDNode *N;
   {
-    sys::SmartScopedReader<true> Reader(pImpl->ConstantsLock);
     N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
   }  
   if (N) return N;
   
-  sys::SmartScopedWriter<true> Writer(pImpl->ConstantsLock);
   N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
   if (!N) {
     // InsertPoint will have been set by the FindNodeOrInsertPos call.
@@ -118,7 +115,6 @@ void MDNode::dropAllReferences() {
 MDNode::~MDNode() {
   {
     LLVMContextImpl *pImpl = getType()->getContext().pImpl;
-    sys::SmartScopedWriter<true> Writer(pImpl->ConstantsLock);
     pImpl->MDNodeSet.RemoveNode(this);
   }
   dropAllReferences();
@@ -147,10 +143,7 @@ void MDNode::replaceElement(Value *From, Value *To) {
     return;
 
   // Remove "this" from the context map. 
-  {
-    sys::SmartScopedWriter<true> Writer(pImpl->ConstantsLock);
-    pImpl->MDNodeSet.RemoveNode(this);
-  }
+  pImpl->MDNodeSet.RemoveNode(this);
 
   // MDNode only lists metadata elements in operand list, because MDNode
   // used by MDNode is considered a valid use. However on the side, MDNode
@@ -186,10 +179,8 @@ void MDNode::replaceElement(Value *From, Value *To) {
   // node with updated "this" node.
   FoldingSetNodeID ID;
   Profile(ID);
-  pImpl->ConstantsLock.reader_acquire();
   void *InsertPoint;
   MDNode *N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
-  pImpl->ConstantsLock.reader_release();
 
   if (N) {
     N->replaceAllUsesWith(this);
@@ -197,14 +188,11 @@ void MDNode::replaceElement(Value *From, Value *To) {
     N = 0;
   }
 
-  {
-    sys::SmartScopedWriter<true> Writer(pImpl->ConstantsLock);
-    N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
-    if (!N) {
-      // InsertPoint will have been set by the FindNodeOrInsertPos call.
-      N = this;
-      pImpl->MDNodeSet.InsertNode(N, InsertPoint);
-    }
+  N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
+  if (!N) {
+    // InsertPoint will have been set by the FindNodeOrInsertPos call.
+    N = this;
+    pImpl->MDNodeSet.InsertNode(N, InsertPoint);
   }
 }