diff --git a/include/llvm/Transforms/Utils/SimplifyLibCalls.h b/include/llvm/Transforms/Utils/SimplifyLibCalls.h
new file mode 100644
index 00000000000..5db2d001814
--- /dev/null
+++ b/include/llvm/Transforms/Utils/SimplifyLibCalls.h
@@ -0,0 +1,43 @@
+//===- SimplifyLibCalls.h - Library call simplifier -------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file exposes an interface to build some C language libcalls for
+// optimization passes that need to call the various functions.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_UTILS_SIMPLIFYLIBCALLS_H
+#define LLVM_TRANSFORMS_UTILS_SIMPLIFYLIBCALLS_H
+
+namespace llvm {
+  class Value;
+  class CallInst;
+  class DataLayout;
+  class TargetLibraryInfo;
+  class LibCallSimplifierImpl;
+
+  /// LibCallSimplifier - This class implements a collection of optimizations
+  /// that replace well formed calls to library functions with a more optimal
+  /// form.  For example, replacing 'printf("Hello!")' with 'puts("Hello!")'.
+  class LibCallSimplifier {
+    /// Impl - A pointer to the actual implementation of the library call
+    /// simplifier.
+    LibCallSimplifierImpl *Impl;
+  public:
+    LibCallSimplifier(const DataLayout *TD, const TargetLibraryInfo *TLI);
+    virtual ~LibCallSimplifier();
+
+    /// optimizeCall - Take the given call instruction and return a more
+    /// optimal value to replace the instruction with or 0 if a more
+    /// optimal form can't be found.
+    Value *optimizeCall(CallInst *CI);
+  };
+} // End llvm namespace
+
+#endif
diff --git a/lib/Transforms/InstCombine/InstCombine.h b/lib/Transforms/InstCombine/InstCombine.h
index 325bb20fbe8..41017c52879 100644
--- a/lib/Transforms/InstCombine/InstCombine.h
+++ b/lib/Transforms/InstCombine/InstCombine.h
@@ -18,6 +18,7 @@
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/Support/InstVisitor.h"
 #include "llvm/Support/TargetFolder.h"
+#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
 
 namespace llvm {
   class CallSite;
@@ -74,6 +75,7 @@ class LLVM_LIBRARY_VISIBILITY InstCombiner
   DataLayout *TD;
   TargetLibraryInfo *TLI;
   bool MadeIRChange;
+  LibCallSimplifier *Simplifier;
 public:
   /// Worklist - All of the instructions that need to be simplified.
   InstCombineWorklist Worklist;
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 04b7b2146f6..34e16c7aeff 100644
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -778,39 +778,6 @@ static bool isSafeToEliminateVarargsCast(const CallSite CS,
   return true;
 }
 
-namespace {
-class InstCombineFortifiedLibCalls : public SimplifyFortifiedLibCalls {
-  InstCombiner *IC;
-protected:
-  void replaceCall(Value *With) {
-    NewInstruction = IC->ReplaceInstUsesWith(*CI, With);
-  }
-  bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const {
-    if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp))
-      return true;
-    if (ConstantInt *SizeCI =
-                           dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) {
-      if (SizeCI->isAllOnesValue())
-        return true;
-      if (isString) {
-        uint64_t Len = GetStringLength(CI->getArgOperand(SizeArgOp));
-        // If the length is 0 we don't know how long it is and so we can't
-        // remove the check.
-        if (Len == 0) return false;
-        return SizeCI->getZExtValue() >= Len;
-      }
-      if (ConstantInt *Arg = dyn_cast<ConstantInt>(
-                                                  CI->getArgOperand(SizeArgOp)))
-        return SizeCI->getZExtValue() >= Arg->getZExtValue();
-    }
-    return false;
-  }
-public:
-  InstCombineFortifiedLibCalls(InstCombiner *IC) : IC(IC), NewInstruction(0) { }
-  Instruction *NewInstruction;
-};
-} // end anonymous namespace
-
 // Try to fold some different type of calls here.
 // Currently we're only working with the checking functions, memcpy_chk,
 // mempcpy_chk, memmove_chk, memset_chk, strcpy_chk, stpcpy_chk, strncpy_chk,
@@ -818,9 +785,10 @@ public:
 Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const DataLayout *TD) {
   if (CI->getCalledFunction() == 0) return 0;
 
-  InstCombineFortifiedLibCalls Simplifier(this);
-  Simplifier.fold(CI, TD, TLI);
-  return Simplifier.NewInstruction;
+  if (Value *With = Simplifier->optimizeCall(CI))
+    return ReplaceInstUsesWith(*CI, With);
+
+  return 0;
 }
 
 static IntrinsicInst *FindInitTrampolineFromAlloca(Value *TrampMem) {
diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index edfc060888b..5356fdcba7c 100644
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2130,6 +2130,9 @@ bool InstCombiner::runOnFunction(Function &F) {
                InstCombineIRInserter(Worklist));
   Builder = &TheBuilder;
 
+  LibCallSimplifier TheSimplifier(TD, TLI);
+  Simplifier = &TheSimplifier;
+
   bool EverMadeChange = false;
 
   // Lower dbg.declare intrinsics otherwise their value may be clobbered
diff --git a/lib/Transforms/Utils/CMakeLists.txt b/lib/Transforms/Utils/CMakeLists.txt
index c3f72b13afc..620209bccbc 100644
--- a/lib/Transforms/Utils/CMakeLists.txt
+++ b/lib/Transforms/Utils/CMakeLists.txt
@@ -28,6 +28,7 @@ add_llvm_library(LLVMTransformUtils
   SimplifyCFG.cpp
   SimplifyIndVar.cpp
   SimplifyInstructions.cpp
+  SimplifyLibCalls.cpp
   UnifyFunctionExitNodes.cpp
   Utils.cpp
   ValueMapper.cpp
diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
new file mode 100644
index 00000000000..7e4c1e70e20
--- /dev/null
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -0,0 +1,289 @@
+//===------ SimplifyLibCalls.cpp - Library calls simplifier ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a utility pass used for testing the InstructionSimplify analysis.
+// The analysis is applied to every instruction, and if it simplifies then the
+// instruction is replaced by the simplification.  If you are looking for a pass
+// that performs serious instruction folding, use the instcombine pass instead.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
+#include "llvm/DataLayout.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Function.h"
+#include "llvm/IRBuilder.h"
+#include "llvm/LLVMContext.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Transforms/Utils/BuildLibCalls.h"
+
+using namespace llvm;
+
+/// This class is the abstract base class for the set of optimizations that
+/// corresponds to one library call.
+namespace {
+class LibCallOptimization {
+protected:
+  Function *Caller;
+  const DataLayout *TD;
+  const TargetLibraryInfo *TLI;
+  LLVMContext* Context;
+public:
+  LibCallOptimization() { }
+  virtual ~LibCallOptimization() {}
+
+  /// callOptimizer - This pure virtual method is implemented by base classes to
+  /// do various optimizations.  If this returns null then no transformation was
+  /// performed.  If it returns CI, then it transformed the call and CI is to be
+  /// deleted.  If it returns something else, replace CI with the new value and
+  /// delete CI.
+  virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B)
+    =0;
+
+  Value *optimizeCall(CallInst *CI, const DataLayout *TD,
+                      const TargetLibraryInfo *TLI, IRBuilder<> &B) {
+    Caller = CI->getParent()->getParent();
+    this->TD = TD;
+    this->TLI = TLI;
+    if (CI->getCalledFunction())
+      Context = &CI->getCalledFunction()->getContext();
+
+    // We never change the calling convention.
+    if (CI->getCallingConv() != llvm::CallingConv::C)
+      return NULL;
+
+    return callOptimizer(CI->getCalledFunction(), CI, B);
+  }
+};
+
+//===----------------------------------------------------------------------===//
+// Fortified Library Call Optimizations
+//===----------------------------------------------------------------------===//
+
+struct FortifiedLibCallOptimization : public LibCallOptimization {
+protected:
+  virtual bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp,
+			  bool isString) const = 0;
+};
+
+struct InstFortifiedLibCallOptimization : public FortifiedLibCallOptimization {
+  CallInst *CI;
+
+  bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const {
+    if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp))
+      return true;
+    if (ConstantInt *SizeCI =
+                           dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) {
+      if (SizeCI->isAllOnesValue())
+        return true;
+      if (isString) {
+        uint64_t Len = GetStringLength(CI->getArgOperand(SizeArgOp));
+        // If the length is 0 we don't know how long it is and so we can't
+        // remove the check.
+        if (Len == 0) return false;
+        return SizeCI->getZExtValue() >= Len;
+      }
+      if (ConstantInt *Arg = dyn_cast<ConstantInt>(
+                                                  CI->getArgOperand(SizeArgOp)))
+        return SizeCI->getZExtValue() >= Arg->getZExtValue();
+    }
+    return false;
+  }
+};
+
+struct MemCpyChkOpt : public InstFortifiedLibCallOptimization {
+  virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    this->CI = CI;
+    FunctionType *FT = Callee->getFunctionType();
+    LLVMContext &Context = CI->getParent()->getContext();
+
+    // Check if this has the right signature.
+    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
+        !FT->getParamType(0)->isPointerTy() ||
+        !FT->getParamType(1)->isPointerTy() ||
+        FT->getParamType(2) != TD->getIntPtrType(Context) ||
+        FT->getParamType(3) != TD->getIntPtrType(Context))
+      return 0;
+
+    if (isFoldable(3, 2, false)) {
+      B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+                     CI->getArgOperand(2), 1);
+      return CI->getArgOperand(0);
+    }
+    return 0;
+  }
+};
+
+struct MemMoveChkOpt : public InstFortifiedLibCallOptimization {
+  virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    this->CI = CI;
+    FunctionType *FT = Callee->getFunctionType();
+    LLVMContext &Context = CI->getParent()->getContext();
+
+    // Check if this has the right signature.
+    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
+        !FT->getParamType(0)->isPointerTy() ||
+        !FT->getParamType(1)->isPointerTy() ||
+        FT->getParamType(2) != TD->getIntPtrType(Context) ||
+        FT->getParamType(3) != TD->getIntPtrType(Context))
+      return 0;
+
+    if (isFoldable(3, 2, false)) {
+      B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
+                      CI->getArgOperand(2), 1);
+      return CI->getArgOperand(0);
+    }
+    return 0;
+  }
+};
+
+struct MemSetChkOpt : public InstFortifiedLibCallOptimization {
+  virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    this->CI = CI;
+    FunctionType *FT = Callee->getFunctionType();
+    LLVMContext &Context = CI->getParent()->getContext();
+
+    // Check if this has the right signature.
+    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
+        !FT->getParamType(0)->isPointerTy() ||
+        !FT->getParamType(1)->isIntegerTy() ||
+        FT->getParamType(2) != TD->getIntPtrType(Context) ||
+        FT->getParamType(3) != TD->getIntPtrType(Context))
+      return 0;
+
+    if (isFoldable(3, 2, false)) {
+      Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(),
+                                   false);
+      B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
+      return CI->getArgOperand(0);
+    }
+    return 0;
+  }
+};
+
+struct StrCpyChkOpt : public InstFortifiedLibCallOptimization {
+  virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    this->CI = CI;
+    StringRef Name = Callee->getName();
+    FunctionType *FT = Callee->getFunctionType();
+    LLVMContext &Context = CI->getParent()->getContext();
+
+    // Check if this has the right signature.
+    if (FT->getNumParams() != 3 ||
+        FT->getReturnType() != FT->getParamType(0) ||
+        FT->getParamType(0) != FT->getParamType(1) ||
+        FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
+        FT->getParamType(2) != TD->getIntPtrType(Context))
+      return 0;
+
+    // If a) we don't have any length information, or b) we know this will
+    // fit then just lower to a plain st[rp]cpy. Otherwise we'll keep our
+    // st[rp]cpy_chk call which may fail at runtime if the size is too long.
+    // TODO: It might be nice to get a maximum length out of the possible
+    // string lengths for varying.
+    if (isFoldable(2, 1, true)) {
+      Value *Ret = EmitStrCpy(CI->getArgOperand(0), CI->getArgOperand(1), B, TD,
+                              TLI, Name.substr(2, 6));
+      return Ret;
+    }
+    return 0;
+  }
+};
+
+struct StrNCpyChkOpt : public InstFortifiedLibCallOptimization {
+  virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    this->CI = CI;
+    StringRef Name = Callee->getName();
+    FunctionType *FT = Callee->getFunctionType();
+    LLVMContext &Context = CI->getParent()->getContext();
+
+    // Check if this has the right signature.
+    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
+        FT->getParamType(0) != FT->getParamType(1) ||
+        FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
+        !FT->getParamType(2)->isIntegerTy() ||
+        FT->getParamType(3) != TD->getIntPtrType(Context))
+      return 0;
+
+    if (isFoldable(3, 2, false)) {
+      Value *Ret = EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+                               CI->getArgOperand(2), B, TD, TLI,
+                               Name.substr(2, 7));
+      return Ret;
+    }
+    return 0;
+  }
+};
+
+} // End anonymous namespace.
+
+namespace llvm {
+
+class LibCallSimplifierImpl {
+  LibCallSimplifier *Simplifier;
+  const DataLayout *TD;
+  const TargetLibraryInfo *TLI;
+  StringMap<LibCallOptimization*> Optimizations;
+
+  // Fortified library call optimizations.
+  MemCpyChkOpt MemCpyChk;
+  MemMoveChkOpt MemMoveChk;
+  MemSetChkOpt MemSetChk;
+  StrCpyChkOpt StrCpyChk;
+  StrNCpyChkOpt StrNCpyChk;
+
+  void initOptimizations();
+public:
+  LibCallSimplifierImpl(const DataLayout *TD, const TargetLibraryInfo *TLI) {
+    this->TD = TD;
+    this->TLI = TLI;
+  }
+
+  Value *optimizeCall(CallInst *CI);
+};
+
+void LibCallSimplifierImpl::initOptimizations() {
+  // Fortified library call optimizations.
+  Optimizations["__memcpy_chk"] = &MemCpyChk;
+  Optimizations["__memmove_chk"] = &MemMoveChk;
+  Optimizations["__memset_chk"] = &MemSetChk;
+  Optimizations["__strcpy_chk"] = &StrCpyChk;
+  Optimizations["__stpcpy_chk"] = &StrCpyChk;
+  Optimizations["__strncpy_chk"] = &StrNCpyChk;
+  Optimizations["__stpncpy_chk"] = &StrNCpyChk;
+}
+
+Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {
+  if (Optimizations.empty())
+    initOptimizations();
+
+  Function *Callee = CI->getCalledFunction();
+  LibCallOptimization *LCO = Optimizations.lookup(Callee->getName());
+  if (LCO) {
+    IRBuilder<> Builder(CI);
+    return LCO->optimizeCall(CI, TD, TLI, Builder);
+  }
+  return 0;
+}
+
+LibCallSimplifier::LibCallSimplifier(const DataLayout *TD,
+                                     const TargetLibraryInfo *TLI) {
+  Impl = new LibCallSimplifierImpl(TD, TLI);
+}
+
+LibCallSimplifier::~LibCallSimplifier() {
+  delete Impl;
+}
+
+Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
+  return Impl->optimizeCall(CI);
+}
+
+}