diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index 95f0ece..8831d35 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -34,8 +34,8 @@
 
 // Error - Simple wrapper function to conditionally assign to E and return true.
 // This just makes error return conditions a little bit simpler...
-static inline bool Error(std::string *E, const std::string &Message) {
-  if (E) *E = Message;
+static inline bool Error(std::string *E, const Twine &Message) {
+  if (E) *E = Message.str();
   return true;
 }
 
diff --git a/lib/Transforms/Scalar/GVNPRE.cpp b/lib/Transforms/Scalar/GVNPRE.cpp
index 4588a7f..4596361 100644
--- a/lib/Transforms/Scalar/GVNPRE.cpp
+++ b/lib/Transforms/Scalar/GVNPRE.cpp
@@ -869,7 +869,8 @@
                                  newOp1, newOp2,
                                  C->getName()+".expr");
       else if (ExtractElementInst* E = dyn_cast<ExtractElementInst>(U))
-        newVal = ExtractElementInst::Create(newOp1, newOp2, E->getName()+".expr");
+        newVal = ExtractElementInst::Create(newOp1, newOp2, 
+                                            E->getName()+".expr");
       
       uint32_t v = VN.lookup_or_add(newVal);
       
diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index 3376e86..a182943 100644
--- a/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -1443,7 +1443,8 @@
     
     if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
       assert(SI->getOperand(0) != Ptr && "Consistency error!");
-      Value *Old = Builder.CreateLoad(NewAI, (NewAI->getName()+".in").c_str());
+      // FIXME: Remove once builder has Twine API.
+      Value *Old = Builder.CreateLoad(NewAI, (NewAI->getName()+".in").str().c_str());
       Value *New = ConvertScalar_InsertValue(SI->getOperand(0), Old, Offset,
                                              Builder);
       Builder.CreateStore(New, NewAI);
@@ -1467,7 +1468,8 @@
           for (unsigned i = 1; i != NumBytes; ++i)
             APVal |= APVal << 8;
         
-        Value *Old = Builder.CreateLoad(NewAI, (NewAI->getName()+".in").c_str());
+        // FIXME: Remove once builder has Twine API.
+        Value *Old = Builder.CreateLoad(NewAI, (NewAI->getName()+".in").str().c_str());
         Value *New = ConvertScalar_InsertValue(
                                     ConstantInt::get(User->getContext(), APVal),
                                                Old, Offset, Builder);
diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp
index df27811..d0fa02c 100644
--- a/lib/VMCore/BasicBlock.cpp
+++ b/lib/VMCore/BasicBlock.cpp
@@ -39,7 +39,7 @@
 template class SymbolTableListTraits<Instruction, BasicBlock>;
 
 
-BasicBlock::BasicBlock(const std::string &Name, Function *NewParent,
+BasicBlock::BasicBlock(const Twine &Name, Function *NewParent,
                        BasicBlock *InsertBefore)
   : Value(Type::LabelTy, Value::BasicBlockVal), Parent(0) {
 
@@ -240,7 +240,7 @@
 /// cause a degenerate basic block to be formed, having a terminator inside of
 /// the basic block).
 ///
-BasicBlock *BasicBlock::splitBasicBlock(iterator I, const std::string &BBName) {
+BasicBlock *BasicBlock::splitBasicBlock(iterator I, const Twine &BBName) {
   assert(getTerminator() && "Can't use splitBasicBlock on degenerate BB!");
   assert(I != InstList.end() &&
          "Trying to get me to create degenerate basic block!");
diff --git a/lib/VMCore/Function.cpp b/lib/VMCore/Function.cpp
index 4923842..cdf2dd0 100644
--- a/lib/VMCore/Function.cpp
+++ b/lib/VMCore/Function.cpp
@@ -36,7 +36,7 @@
 // Argument Implementation
 //===----------------------------------------------------------------------===//
 
-Argument::Argument(const Type *Ty, const std::string &Name, Function *Par)
+Argument::Argument(const Type *Ty, const Twine &Name, Function *Par)
   : Value(Ty, Value::ArgumentVal) {
   Parent = 0;
 
@@ -144,7 +144,7 @@
 //===----------------------------------------------------------------------===//
 
 Function::Function(const FunctionType *Ty, LinkageTypes Linkage,
-                   const std::string &name, Module *ParentModule)
+                   const Twine &name, Module *ParentModule)
   : GlobalValue(PointerType::getUnqual(Ty), 
                 Value::FunctionVal, 0, 0, Linkage, name) {
   assert(FunctionType::isValidReturnType(getReturnType()) &&
diff --git a/lib/VMCore/Globals.cpp b/lib/VMCore/Globals.cpp
index bb750be..aa4c30a 100644
--- a/lib/VMCore/Globals.cpp
+++ b/lib/VMCore/Globals.cpp
@@ -96,7 +96,7 @@
 
 GlobalVariable::GlobalVariable(LLVMContext &Context, const Type *Ty,
                                bool constant, LinkageTypes Link,
-                               Constant *InitVal, const std::string &Name,
+                               Constant *InitVal, const Twine &Name,
                                bool ThreadLocal, unsigned AddressSpace)
   : GlobalValue(Context.getPointerType(Ty, AddressSpace), 
                 Value::GlobalVariableVal,
@@ -114,7 +114,7 @@
 
 GlobalVariable::GlobalVariable(Module &M, const Type *Ty, bool constant,
                                LinkageTypes Link, Constant *InitVal,
-                               const std::string &Name,
+                               const Twine &Name,
                                GlobalVariable *Before, bool ThreadLocal,
                                unsigned AddressSpace)
   : GlobalValue(M.getContext().getPointerType(Ty, AddressSpace), 
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index e1583c9..20de3fe 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -351,7 +351,7 @@
   assert(FTy->getNumParams() == 0 && "Calling a function with bad signature");
 }
 
-CallInst::CallInst(Value *Func, Value* Actual, const std::string &Name,
+CallInst::CallInst(Value *Func, Value* Actual, const Twine &Name,
                    Instruction *InsertBefore)
   : Instruction(cast<FunctionType>(cast<PointerType>(Func->getType())
                                    ->getElementType())->getReturnType(),
@@ -362,7 +362,7 @@
   setName(Name);
 }
 
-CallInst::CallInst(Value *Func, Value* Actual, const std::string &Name,
+CallInst::CallInst(Value *Func, Value* Actual, const Twine &Name,
                    BasicBlock  *InsertAtEnd)
   : Instruction(cast<FunctionType>(cast<PointerType>(Func->getType())
                                    ->getElementType())->getReturnType(),
@@ -372,7 +372,7 @@
   init(Func, Actual);
   setName(Name);
 }
-CallInst::CallInst(Value *Func, const std::string &Name,
+CallInst::CallInst(Value *Func, const Twine &Name,
                    Instruction *InsertBefore)
   : Instruction(cast<FunctionType>(cast<PointerType>(Func->getType())
                                    ->getElementType())->getReturnType(),
@@ -383,7 +383,7 @@
   setName(Name);
 }
 
-CallInst::CallInst(Value *Func, const std::string &Name,
+CallInst::CallInst(Value *Func, const Twine &Name,
                    BasicBlock *InsertAtEnd)
   : Instruction(cast<FunctionType>(cast<PointerType>(Func->getType())
                                    ->getElementType())->getReturnType(),
@@ -714,7 +714,7 @@
 }
 
 AllocationInst::AllocationInst(const Type *Ty, Value *ArraySize, unsigned iTy,
-                               unsigned Align, const std::string &Name,
+                               unsigned Align, const Twine &Name,
                                Instruction *InsertBefore)
   : UnaryInstruction(Ty->getContext().getPointerTypeUnqual(Ty), iTy,
                      getAISize(Ty->getContext(), ArraySize), InsertBefore) {
@@ -724,7 +724,7 @@
 }
 
 AllocationInst::AllocationInst(const Type *Ty, Value *ArraySize, unsigned iTy,
-                               unsigned Align, const std::string &Name,
+                               unsigned Align, const Twine &Name,
                                BasicBlock *InsertAtEnd)
   : UnaryInstruction(Ty->getContext().getPointerTypeUnqual(Ty), iTy,
                      getAISize(Ty->getContext(), ArraySize), InsertAtEnd) {
@@ -806,7 +806,7 @@
          "Ptr must have pointer type.");
 }
 
-LoadInst::LoadInst(Value *Ptr, const std::string &Name, Instruction *InsertBef)
+LoadInst::LoadInst(Value *Ptr, const Twine &Name, Instruction *InsertBef)
   : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                      Load, Ptr, InsertBef) {
   setVolatile(false);
@@ -815,7 +815,7 @@
   setName(Name);
 }
 
-LoadInst::LoadInst(Value *Ptr, const std::string &Name, BasicBlock *InsertAE)
+LoadInst::LoadInst(Value *Ptr, const Twine &Name, BasicBlock *InsertAE)
   : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                      Load, Ptr, InsertAE) {
   setVolatile(false);
@@ -824,7 +824,7 @@
   setName(Name);
 }
 
-LoadInst::LoadInst(Value *Ptr, const std::string &Name, bool isVolatile,
+LoadInst::LoadInst(Value *Ptr, const Twine &Name, bool isVolatile,
                    Instruction *InsertBef)
   : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                      Load, Ptr, InsertBef) {
@@ -834,7 +834,7 @@
   setName(Name);
 }
 
-LoadInst::LoadInst(Value *Ptr, const std::string &Name, bool isVolatile, 
+LoadInst::LoadInst(Value *Ptr, const Twine &Name, bool isVolatile, 
                    unsigned Align, Instruction *InsertBef)
   : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                      Load, Ptr, InsertBef) {
@@ -844,7 +844,7 @@
   setName(Name);
 }
 
-LoadInst::LoadInst(Value *Ptr, const std::string &Name, bool isVolatile, 
+LoadInst::LoadInst(Value *Ptr, const Twine &Name, bool isVolatile, 
                    unsigned Align, BasicBlock *InsertAE)
   : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                      Load, Ptr, InsertAE) {
@@ -854,7 +854,7 @@
   setName(Name);
 }
 
-LoadInst::LoadInst(Value *Ptr, const std::string &Name, bool isVolatile,
+LoadInst::LoadInst(Value *Ptr, const Twine &Name, bool isVolatile,
                    BasicBlock *InsertAE)
   : UnaryInstruction(cast<PointerType>(Ptr->getType())->getElementType(),
                      Load, Ptr, InsertAE) {
@@ -1013,7 +1013,7 @@
 }
 
 void GetElementPtrInst::init(Value *Ptr, Value* const *Idx, unsigned NumIdx,
-                             const std::string &Name) {
+                             const Twine &Name) {
   assert(NumOperands == 1+NumIdx && "NumOperands not initialized?");
   Use *OL = OperandList;
   OL[0] = Ptr;
@@ -1024,7 +1024,7 @@
   setName(Name);
 }
 
-void GetElementPtrInst::init(Value *Ptr, Value *Idx, const std::string &Name) {
+void GetElementPtrInst::init(Value *Ptr, Value *Idx, const Twine &Name) {
   assert(NumOperands == 2 && "NumOperands not initialized?");
   Use *OL = OperandList;
   OL[0] = Ptr;
@@ -1045,7 +1045,7 @@
 }
 
 GetElementPtrInst::GetElementPtrInst(Value *Ptr, Value *Idx,
-                                     const std::string &Name, Instruction *InBe)
+                                     const Twine &Name, Instruction *InBe)
   : Instruction(Ptr->getType()->getContext().getPointerType(
       checkType(getIndexedType(Ptr->getType(),Idx)), retrieveAddrSpace(Ptr)),
                 GetElementPtr,
@@ -1055,7 +1055,7 @@
 }
 
 GetElementPtrInst::GetElementPtrInst(Value *Ptr, Value *Idx,
-                                     const std::string &Name, BasicBlock *IAE)
+                                     const Twine &Name, BasicBlock *IAE)
   : Instruction(Ptr->getType()->getContext().getPointerType(
             checkType(getIndexedType(Ptr->getType(),Idx)),  
                 retrieveAddrSpace(Ptr)),
@@ -1164,7 +1164,7 @@
 //===----------------------------------------------------------------------===//
 
 ExtractElementInst::ExtractElementInst(Value *Val, Value *Index,
-                                       const std::string &Name,
+                                       const Twine &Name,
                                        Instruction *InsertBef)
   : Instruction(cast<VectorType>(Val->getType())->getElementType(),
                 ExtractElement,
@@ -1178,7 +1178,7 @@
 }
 
 ExtractElementInst::ExtractElementInst(Value *Val, Value *Index,
-                                       const std::string &Name,
+                                       const Twine &Name,
                                        BasicBlock *InsertAE)
   : Instruction(cast<VectorType>(Val->getType())->getElementType(),
                 ExtractElement,
@@ -1212,7 +1212,7 @@
   Op<2>() = IE.Op<2>();
 }
 InsertElementInst::InsertElementInst(Value *Vec, Value *Elt, Value *Index,
-                                     const std::string &Name,
+                                     const Twine &Name,
                                      Instruction *InsertBef)
   : Instruction(Vec->getType(), InsertElement,
                 OperandTraits<InsertElementInst>::op_begin(this),
@@ -1226,7 +1226,7 @@
 }
 
 InsertElementInst::InsertElementInst(Value *Vec, Value *Elt, Value *Index,
-                                     const std::string &Name,
+                                     const Twine &Name,
                                      BasicBlock *InsertAE)
   : Instruction(Vec->getType(), InsertElement,
                 OperandTraits<InsertElementInst>::op_begin(this),
@@ -1268,7 +1268,7 @@
 }
 
 ShuffleVectorInst::ShuffleVectorInst(Value *V1, Value *V2, Value *Mask,
-                                     const std::string &Name,
+                                     const Twine &Name,
                                      Instruction *InsertBefore)
 : Instruction(V1->getType()->getContext().getVectorType(
                               cast<VectorType>(V1->getType())->getElementType(),
@@ -1286,7 +1286,7 @@
 }
 
 ShuffleVectorInst::ShuffleVectorInst(Value *V1, Value *V2, Value *Mask,
-                                     const std::string &Name,
+                                     const Twine &Name,
                                      BasicBlock *InsertAtEnd)
   : Instruction(V1->getType(), ShuffleVector,
                 OperandTraits<ShuffleVectorInst>::op_begin(this),
@@ -1333,7 +1333,7 @@
 //===----------------------------------------------------------------------===//
 
 void InsertValueInst::init(Value *Agg, Value *Val, const unsigned *Idx, 
-                           unsigned NumIdx, const std::string &Name) {
+                           unsigned NumIdx, const Twine &Name) {
   assert(NumOperands == 2 && "NumOperands not initialized?");
   Op<0>() = Agg;
   Op<1>() = Val;
@@ -1343,7 +1343,7 @@
 }
 
 void InsertValueInst::init(Value *Agg, Value *Val, unsigned Idx, 
-                           const std::string &Name) {
+                           const Twine &Name) {
   assert(NumOperands == 2 && "NumOperands not initialized?");
   Op<0>() = Agg;
   Op<1>() = Val;
@@ -1363,7 +1363,7 @@
 InsertValueInst::InsertValueInst(Value *Agg,
                                  Value *Val,
                                  unsigned Idx, 
-                                 const std::string &Name,
+                                 const Twine &Name,
                                  Instruction *InsertBefore)
   : Instruction(Agg->getType(), InsertValue,
                 OperandTraits<InsertValueInst>::op_begin(this),
@@ -1374,7 +1374,7 @@
 InsertValueInst::InsertValueInst(Value *Agg,
                                  Value *Val,
                                  unsigned Idx, 
-                                 const std::string &Name,
+                                 const Twine &Name,
                                  BasicBlock *InsertAtEnd)
   : Instruction(Agg->getType(), InsertValue,
                 OperandTraits<InsertValueInst>::op_begin(this),
@@ -1387,14 +1387,14 @@
 //===----------------------------------------------------------------------===//
 
 void ExtractValueInst::init(const unsigned *Idx, unsigned NumIdx,
-                            const std::string &Name) {
+                            const Twine &Name) {
   assert(NumOperands == 1 && "NumOperands not initialized?");
 
   Indices.insert(Indices.end(), Idx, Idx + NumIdx);
   setName(Name);
 }
 
-void ExtractValueInst::init(unsigned Idx, const std::string &Name) {
+void ExtractValueInst::init(unsigned Idx, const Twine &Name) {
   assert(NumOperands == 1 && "NumOperands not initialized?");
 
   Indices.push_back(Idx);
@@ -1457,7 +1457,7 @@
 }
 
 BinaryOperator::BinaryOperator(BinaryOps iType, Value *S1, Value *S2,
-                               const Type *Ty, const std::string &Name,
+                               const Type *Ty, const Twine &Name,
                                Instruction *InsertBefore)
   : Instruction(Ty, AdjustIType(iType, Ty),
                 OperandTraits<BinaryOperator>::op_begin(this),
@@ -1470,7 +1470,7 @@
 }
 
 BinaryOperator::BinaryOperator(BinaryOps iType, Value *S1, Value *S2, 
-                               const Type *Ty, const std::string &Name,
+                               const Type *Ty, const Twine &Name,
                                BasicBlock *InsertAtEnd)
   : Instruction(Ty, AdjustIType(iType, Ty),
                 OperandTraits<BinaryOperator>::op_begin(this),
@@ -1559,7 +1559,7 @@
 }
 
 BinaryOperator *BinaryOperator::Create(BinaryOps Op, Value *S1, Value *S2,
-                                       const std::string &Name,
+                                       const Twine &Name,
                                        Instruction *InsertBefore) {
   assert(S1->getType() == S2->getType() &&
          "Cannot create binary operator with two operands of differing type!");
@@ -1567,7 +1567,7 @@
 }
 
 BinaryOperator *BinaryOperator::Create(BinaryOps Op, Value *S1, Value *S2,
-                                       const std::string &Name,
+                                       const Twine &Name,
                                        BasicBlock *InsertAtEnd) {
   BinaryOperator *Res = Create(Op, S1, S2, Name);
   InsertAtEnd->getInstList().push_back(Res);
@@ -1575,7 +1575,7 @@
 }
 
 BinaryOperator *BinaryOperator::CreateNeg(LLVMContext &Context,
-                                          Value *Op, const std::string &Name,
+                                          Value *Op, const Twine &Name,
                                           Instruction *InsertBefore) {
   Value *zero = Context.getZeroValueForNegation(Op->getType());
   return new BinaryOperator(Instruction::Sub,
@@ -1584,7 +1584,7 @@
 }
 
 BinaryOperator *BinaryOperator::CreateNeg(LLVMContext &Context, 
-                                          Value *Op, const std::string &Name,
+                                          Value *Op, const Twine &Name,
                                           BasicBlock *InsertAtEnd) {
   Value *zero = Context.getZeroValueForNegation(Op->getType());
   return new BinaryOperator(Instruction::Sub,
@@ -1593,7 +1593,7 @@
 }
 
 BinaryOperator *BinaryOperator::CreateFNeg(LLVMContext &Context,
-                                           Value *Op, const std::string &Name,
+                                           Value *Op, const Twine &Name,
                                            Instruction *InsertBefore) {
   Value *zero = Context.getZeroValueForNegation(Op->getType());
   return new BinaryOperator(Instruction::FSub,
@@ -1602,7 +1602,7 @@
 }
 
 BinaryOperator *BinaryOperator::CreateFNeg(LLVMContext &Context,
-                                           Value *Op, const std::string &Name,
+                                           Value *Op, const Twine &Name,
                                            BasicBlock *InsertAtEnd) {
   Value *zero = Context.getZeroValueForNegation(Op->getType());
   return new BinaryOperator(Instruction::FSub,
@@ -1611,7 +1611,7 @@
 }
 
 BinaryOperator *BinaryOperator::CreateNot(LLVMContext &Context,
-                                          Value *Op, const std::string &Name,
+                                          Value *Op, const Twine &Name,
                                           Instruction *InsertBefore) {
   Constant *C;
   if (const VectorType *PTy = dyn_cast<VectorType>(Op->getType())) {
@@ -1627,7 +1627,7 @@
 }
 
 BinaryOperator *BinaryOperator::CreateNot(LLVMContext &Context,
-                                          Value *Op, const std::string &Name,
+                                          Value *Op, const Twine &Name,
                                           BasicBlock *InsertAtEnd) {
   Constant *AllOnes;
   if (const VectorType *PTy = dyn_cast<VectorType>(Op->getType())) {
@@ -1952,7 +1952,7 @@
 }
 
 CastInst *CastInst::Create(Instruction::CastOps op, Value *S, const Type *Ty, 
-  const std::string &Name, Instruction *InsertBefore) {
+  const Twine &Name, Instruction *InsertBefore) {
   // Construct and return the appropriate CastInst subclass
   switch (op) {
     case Trunc:    return new TruncInst    (S, Ty, Name, InsertBefore);
@@ -1974,7 +1974,7 @@
 }
 
 CastInst *CastInst::Create(Instruction::CastOps op, Value *S, const Type *Ty,
-  const std::string &Name, BasicBlock *InsertAtEnd) {
+  const Twine &Name, BasicBlock *InsertAtEnd) {
   // Construct and return the appropriate CastInst subclass
   switch (op) {
     case Trunc:    return new TruncInst    (S, Ty, Name, InsertAtEnd);
@@ -1996,7 +1996,7 @@
 }
 
 CastInst *CastInst::CreateZExtOrBitCast(Value *S, const Type *Ty, 
-                                        const std::string &Name,
+                                        const Twine &Name,
                                         Instruction *InsertBefore) {
   if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
     return Create(Instruction::BitCast, S, Ty, Name, InsertBefore);
@@ -2004,7 +2004,7 @@
 }
 
 CastInst *CastInst::CreateZExtOrBitCast(Value *S, const Type *Ty, 
-                                        const std::string &Name,
+                                        const Twine &Name,
                                         BasicBlock *InsertAtEnd) {
   if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
     return Create(Instruction::BitCast, S, Ty, Name, InsertAtEnd);
@@ -2012,7 +2012,7 @@
 }
 
 CastInst *CastInst::CreateSExtOrBitCast(Value *S, const Type *Ty, 
-                                        const std::string &Name,
+                                        const Twine &Name,
                                         Instruction *InsertBefore) {
   if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
     return Create(Instruction::BitCast, S, Ty, Name, InsertBefore);
@@ -2020,7 +2020,7 @@
 }
 
 CastInst *CastInst::CreateSExtOrBitCast(Value *S, const Type *Ty, 
-                                        const std::string &Name,
+                                        const Twine &Name,
                                         BasicBlock *InsertAtEnd) {
   if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
     return Create(Instruction::BitCast, S, Ty, Name, InsertAtEnd);
@@ -2028,7 +2028,7 @@
 }
 
 CastInst *CastInst::CreateTruncOrBitCast(Value *S, const Type *Ty,
-                                         const std::string &Name,
+                                         const Twine &Name,
                                          Instruction *InsertBefore) {
   if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
     return Create(Instruction::BitCast, S, Ty, Name, InsertBefore);
@@ -2036,7 +2036,7 @@
 }
 
 CastInst *CastInst::CreateTruncOrBitCast(Value *S, const Type *Ty,
-                                         const std::string &Name, 
+                                         const Twine &Name, 
                                          BasicBlock *InsertAtEnd) {
   if (S->getType()->getScalarSizeInBits() == Ty->getScalarSizeInBits())
     return Create(Instruction::BitCast, S, Ty, Name, InsertAtEnd);
@@ -2044,7 +2044,7 @@
 }
 
 CastInst *CastInst::CreatePointerCast(Value *S, const Type *Ty,
-                                      const std::string &Name,
+                                      const Twine &Name,
                                       BasicBlock *InsertAtEnd) {
   assert(isa<PointerType>(S->getType()) && "Invalid cast");
   assert((Ty->isInteger() || isa<PointerType>(Ty)) &&
@@ -2057,7 +2057,7 @@
 
 /// @brief Create a BitCast or a PtrToInt cast instruction
 CastInst *CastInst::CreatePointerCast(Value *S, const Type *Ty, 
-                                      const std::string &Name, 
+                                      const Twine &Name, 
                                       Instruction *InsertBefore) {
   assert(isa<PointerType>(S->getType()) && "Invalid cast");
   assert((Ty->isInteger() || isa<PointerType>(Ty)) &&
@@ -2069,7 +2069,7 @@
 }
 
 CastInst *CastInst::CreateIntegerCast(Value *C, const Type *Ty, 
-                                      bool isSigned, const std::string &Name,
+                                      bool isSigned, const Twine &Name,
                                       Instruction *InsertBefore) {
   assert(C->getType()->isInteger() && Ty->isInteger() && "Invalid cast");
   unsigned SrcBits = C->getType()->getScalarSizeInBits();
@@ -2082,7 +2082,7 @@
 }
 
 CastInst *CastInst::CreateIntegerCast(Value *C, const Type *Ty, 
-                                      bool isSigned, const std::string &Name,
+                                      bool isSigned, const Twine &Name,
                                       BasicBlock *InsertAtEnd) {
   assert(C->getType()->isIntOrIntVector() && Ty->isIntOrIntVector() &&
          "Invalid cast");
@@ -2096,7 +2096,7 @@
 }
 
 CastInst *CastInst::CreateFPCast(Value *C, const Type *Ty, 
-                                 const std::string &Name, 
+                                 const Twine &Name, 
                                  Instruction *InsertBefore) {
   assert(C->getType()->isFPOrFPVector() && Ty->isFPOrFPVector() &&
          "Invalid cast");
@@ -2109,7 +2109,7 @@
 }
 
 CastInst *CastInst::CreateFPCast(Value *C, const Type *Ty, 
-                                 const std::string &Name, 
+                                 const Twine &Name, 
                                  BasicBlock *InsertAtEnd) {
   assert(C->getType()->isFPOrFPVector() && Ty->isFPOrFPVector() &&
          "Invalid cast");
@@ -2353,144 +2353,144 @@
 }
 
 TruncInst::TruncInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, Trunc, S, Name, InsertBefore) {
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal Trunc");
 }
 
 TruncInst::TruncInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 ) : CastInst(Ty, Trunc, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal Trunc");
 }
 
 ZExtInst::ZExtInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 )  : CastInst(Ty, ZExt, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal ZExt");
 }
 
 ZExtInst::ZExtInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 )  : CastInst(Ty, ZExt, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal ZExt");
 }
 SExtInst::SExtInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, SExt, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal SExt");
 }
 
 SExtInst::SExtInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 )  : CastInst(Ty, SExt, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal SExt");
 }
 
 FPTruncInst::FPTruncInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, FPTrunc, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPTrunc");
 }
 
 FPTruncInst::FPTruncInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 ) : CastInst(Ty, FPTrunc, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPTrunc");
 }
 
 FPExtInst::FPExtInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, FPExt, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPExt");
 }
 
 FPExtInst::FPExtInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 ) : CastInst(Ty, FPExt, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPExt");
 }
 
 UIToFPInst::UIToFPInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, UIToFP, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal UIToFP");
 }
 
 UIToFPInst::UIToFPInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 ) : CastInst(Ty, UIToFP, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal UIToFP");
 }
 
 SIToFPInst::SIToFPInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, SIToFP, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal SIToFP");
 }
 
 SIToFPInst::SIToFPInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 ) : CastInst(Ty, SIToFP, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal SIToFP");
 }
 
 FPToUIInst::FPToUIInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, FPToUI, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPToUI");
 }
 
 FPToUIInst::FPToUIInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 ) : CastInst(Ty, FPToUI, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPToUI");
 }
 
 FPToSIInst::FPToSIInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, FPToSI, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPToSI");
 }
 
 FPToSIInst::FPToSIInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 ) : CastInst(Ty, FPToSI, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal FPToSI");
 }
 
 PtrToIntInst::PtrToIntInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, PtrToInt, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal PtrToInt");
 }
 
 PtrToIntInst::PtrToIntInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 ) : CastInst(Ty, PtrToInt, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal PtrToInt");
 }
 
 IntToPtrInst::IntToPtrInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, IntToPtr, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal IntToPtr");
 }
 
 IntToPtrInst::IntToPtrInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 ) : CastInst(Ty, IntToPtr, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal IntToPtr");
 }
 
 BitCastInst::BitCastInst(
-  Value *S, const Type *Ty, const std::string &Name, Instruction *InsertBefore
+  Value *S, const Type *Ty, const Twine &Name, Instruction *InsertBefore
 ) : CastInst(Ty, BitCast, S, Name, InsertBefore) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal BitCast");
 }
 
 BitCastInst::BitCastInst(
-  Value *S, const Type *Ty, const std::string &Name, BasicBlock *InsertAtEnd
+  Value *S, const Type *Ty, const Twine &Name, BasicBlock *InsertAtEnd
 ) : CastInst(Ty, BitCast, S, Name, InsertAtEnd) { 
   assert(castIsValid(getOpcode(), S, Ty) && "Illegal BitCast");
 }
@@ -2500,7 +2500,7 @@
 //===----------------------------------------------------------------------===//
 
 CmpInst::CmpInst(const Type *ty, OtherOps op, unsigned short predicate,
-                 Value *LHS, Value *RHS, const std::string &Name,
+                 Value *LHS, Value *RHS, const Twine &Name,
                  Instruction *InsertBefore)
   : Instruction(ty, op,
                 OperandTraits<CmpInst>::op_begin(this),
@@ -2513,7 +2513,7 @@
 }
 
 CmpInst::CmpInst(const Type *ty, OtherOps op, unsigned short predicate,
-                 Value *LHS, Value *RHS, const std::string &Name,
+                 Value *LHS, Value *RHS, const Twine &Name,
                  BasicBlock *InsertAtEnd)
   : Instruction(ty, op,
                 OperandTraits<CmpInst>::op_begin(this),
@@ -2528,7 +2528,7 @@
 CmpInst *
 CmpInst::Create(LLVMContext &Context, OtherOps Op, unsigned short predicate,
                 Value *S1, Value *S2, 
-                const std::string &Name, Instruction *InsertBefore) {
+                const Twine &Name, Instruction *InsertBefore) {
   if (Op == Instruction::ICmp) {
     if (InsertBefore)
       return new ICmpInst(InsertBefore, CmpInst::Predicate(predicate),
@@ -2548,7 +2548,7 @@
 
 CmpInst *
 CmpInst::Create(OtherOps Op, unsigned short predicate, Value *S1, Value *S2, 
-                const std::string &Name, BasicBlock *InsertAtEnd) {
+                const Twine &Name, BasicBlock *InsertAtEnd) {
   if (Op == Instruction::ICmp) {
     return new ICmpInst(*InsertAtEnd, CmpInst::Predicate(predicate),
                         S1, S2, Name);
diff --git a/lib/VMCore/Value.cpp b/lib/VMCore/Value.cpp
index 71dec84..d020c39 100644
--- a/lib/VMCore/Value.cpp
+++ b/lib/VMCore/Value.cpp
@@ -20,6 +20,7 @@
 #include "llvm/Module.h"
 #include "llvm/MDNode.h"
 #include "llvm/ValueSymbolTable.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/LeakDetector.h"
@@ -183,8 +184,10 @@
   return StringRef(Name->getKeyData(), Name->getKeyLength());
 }
 
-void Value::setName(const std::string &name) {
-  setName(&name[0], name.size());
+void Value::setName(const Twine &Name) {
+  SmallString<32> NameData;
+  Name.toVector(NameData);
+  setName(NameData.begin(), NameData.size());
 }
 
 void Value::setName(const char *Name) {
diff --git a/lib/VMCore/Verifier.cpp b/lib/VMCore/Verifier.cpp
index 4b15e3a..f900dca 100644
--- a/lib/VMCore/Verifier.cpp
+++ b/lib/VMCore/Verifier.cpp
@@ -304,10 +304,10 @@
     // CheckFailed - A check failed, so print out the condition and the message
     // that failed.  This provides a nice place to put a breakpoint if you want
     // to see why something is not correct.
-    void CheckFailed(const std::string &Message,
+    void CheckFailed(const Twine &Message,
                      const Value *V1 = 0, const Value *V2 = 0,
                      const Value *V3 = 0, const Value *V4 = 0) {
-      msgs << Message << "\n";
+      msgs << Message.str() << "\n";
       WriteValue(V1);
       WriteValue(V2);
       WriteValue(V3);
@@ -315,9 +315,9 @@
       Broken = true;
     }
 
-    void CheckFailed( const std::string& Message, const Value* V1,
-                      const Type* T2, const Value* V3 = 0 ) {
-      msgs << Message << "\n";
+    void CheckFailed(const Twine &Message, const Value* V1,
+                     const Type* T2, const Value* V3 = 0) {
+      msgs << Message.str() << "\n";
       WriteValue(V1);
       WriteType(T2);
       WriteValue(V3);