X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FIPO%2FSimplifyLibCalls.cpp;h=b4e840641b576d43f2e17ddf36216da04ff790d2;hb=e4d87aa2de6e52952dca73716386db09aad5a8fd;hp=95faac2071327edfc50f87823b72fd1c4e296819;hpb=9f56b1feeb9f2d50fdf5bb9e9a71a0973ae33ef7;p=oota-llvm.git

diff --git a/lib/Transforms/IPO/SimplifyLibCalls.cpp b/lib/Transforms/IPO/SimplifyLibCalls.cpp
index 95faac20713..b4e840641b5 100644
--- a/lib/Transforms/IPO/SimplifyLibCalls.cpp
+++ b/lib/Transforms/IPO/SimplifyLibCalls.cpp
@@ -2,17 +2,18 @@
 //
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by Reid Spencer and is distributed under the 
+// This file was developed by Reid Spencer and is distributed under the
 // University of Illinois Open Source License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
-// This file implements a variety of small optimizations for calls to specific
-// well-known (e.g. runtime library) function calls. For example, a call to the
-// function "exit(3)" that occurs within the main() function can be transformed
-// into a simple "return 3" instruction. Any optimization that takes this form
-// (replace call to library function with simpler code that provides same 
-// result) belongs in this file. 
+// This file implements a module pass that applies a variety of small
+// optimizations for calls to specific well-known function calls (e.g. runtime
+// library functions). For example, a call to the function "exit(3)" that
+// occurs within the main() function can be transformed into a simple "return 3"
+// instruction. Any optimization that takes this form (replace call to library
+// function with simpler code that provides the same result) belongs in this
+// file.
 //
 //===----------------------------------------------------------------------===//
 
@@ -24,69 +25,83 @@
 #include "llvm/Pass.h"
 #include "llvm/ADT/hash_map"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Config/config.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Transforms/IPO.h"
-#include <iostream>
 using namespace llvm;
 
-namespace {
-
 /// This statistic keeps track of the total number of library calls that have
 /// been simplified regardless of which call it is.
-Statistic<> SimplifiedLibCalls("simplify-libcalls", 
-  "Number of well-known library calls simplified");
-
-// Forward declarations
-class LibCallOptimization;
-class SimplifyLibCalls;
+STATISTIC(SimplifiedLibCalls, "Number of library calls simplified");
 
+namespace {
+  // Forward declarations
+  class LibCallOptimization;
+  class SimplifyLibCalls;
+  
+/// This list is populated by the constructor for LibCallOptimization class.
+/// Therefore all subclasses are registered here at static initialization time
+/// and this list is what the SimplifyLibCalls pass uses to apply the individual
+/// optimizations to the call sites.
 /// @brief The list of optimizations deriving from LibCallOptimization
-hash_map<std::string,LibCallOptimization*> optlist;
+static LibCallOptimization *OptList = 0;
 
 /// This class is the abstract base class for the set of optimizations that
 /// corresponds to one library call. The SimplifyLibCalls pass will call the
 /// ValidateCalledFunction method to ask the optimization if a given Function
 /// is the kind that the optimization can handle. If the subclass returns true,
-/// then SImplifyLibCalls will also call the OptimizeCall method to perform, 
+/// then SImplifyLibCalls will also call the OptimizeCall method to perform,
 /// or attempt to perform, the optimization(s) for the library call. Otherwise,
 /// OptimizeCall won't be called. Subclasses are responsible for providing the
 /// name of the library call (strlen, strcpy, etc.) to the LibCallOptimization
 /// constructor. This is used to efficiently select which call instructions to
-/// optimize. The criteria for a "lib call" is "anything with well known 
+/// optimize. The criteria for a "lib call" is "anything with well known
 /// semantics", typically a library function that is defined by an international
-/// standard. Because the semantics are well known, the optimizations can 
+/// standard. Because the semantics are well known, the optimizations can
 /// generally short-circuit actually calling the function if there's a simpler
 /// way (e.g. strlen(X) can be reduced to a constant if X is a constant global).
 /// @brief Base class for library call optimizations
-class LibCallOptimization
-{
+class LibCallOptimization {
+  LibCallOptimization **Prev, *Next;
+  const char *FunctionName; ///< Name of the library call we optimize
+#ifndef NDEBUG
+  Statistic occurrences; ///< debug statistic (-debug-only=simplify-libcalls)
+#endif
 public:
-  /// The \p fname argument must be the name of the library function being 
+  /// The \p fname argument must be the name of the library function being
   /// optimized by the subclass.
   /// @brief Constructor that registers the optimization.
-  LibCallOptimization(const char * fname )
-    : func_name(fname)
+  LibCallOptimization(const char *FName, const char *Description)
+    : FunctionName(FName) {
+      
 #ifndef NDEBUG
-    , stat_name(std::string("simplify-libcalls:")+fname)
-    , stat_desc(std::string("Number of ")+fname+"(...) calls simplified")
-    , occurrences(stat_name.c_str(),stat_desc.c_str())
+    occurrences.construct("simplify-libcalls", Description);
 #endif
-  {
-    // Register this call optimizer in the optlist (a hash_map)
-    optlist[func_name] = this;
+    // Register this optimizer in the list of optimizations.
+    Next = OptList;
+    OptList = this;
+    Prev = &OptList;
+    if (Next) Next->Prev = &Next;
   }
+  
+  /// getNext - All libcall optimizations are chained together into a list,
+  /// return the next one in the list.
+  LibCallOptimization *getNext() { return Next; }
 
   /// @brief Deregister from the optlist
-  virtual ~LibCallOptimization() { optlist.erase(func_name); }
+  virtual ~LibCallOptimization() {
+    *Prev = Next;
+    if (Next) Next->Prev = Prev;
+  }
 
   /// The implementation of this function in subclasses should determine if
-  /// \p F is suitable for the optimization. This method is called by 
-  /// SimplifyLibCalls::runOnModule to short circuit visiting all the call 
-  /// sites of such a function if that function is not suitable in the first 
+  /// \p F is suitable for the optimization. This method is called by
+  /// SimplifyLibCalls::runOnModule to short circuit visiting all the call
+  /// sites of such a function if that function is not suitable in the first
   /// place.  If the called function is suitabe, this method should return true;
-  /// false, otherwise. This function should also perform any lazy 
-  /// initialization that the LibCallOptimization needs to do, if its to return 
+  /// false, otherwise. This function should also perform any lazy
+  /// initialization that the LibCallOptimization needs to do, if its to return
   /// true. This avoids doing initialization until the optimizer is actually
   /// going to be called upon to do some optimization.
   /// @brief Determine if the function is suitable for optimization
@@ -95,10 +110,10 @@ public:
     SimplifyLibCalls& SLC ///< The pass object invoking us
   ) = 0;
 
-  /// The implementations of this function in subclasses is the heart of the 
-  /// SimplifyLibCalls algorithm. Sublcasses of this class implement 
+  /// The implementations of this function in subclasses is the heart of the
+  /// SimplifyLibCalls algorithm. Sublcasses of this class implement
   /// OptimizeCall to determine if (a) the conditions are right for optimizing
-  /// the call and (b) to perform the optimization. If an action is taken 
+  /// the call and (b) to perform the optimization. If an action is taken
   /// against ci, the subclass is responsible for returning true and ensuring
   /// that ci is erased from its parent.
   /// @brief Optimize a call, if possible.
@@ -108,38 +123,31 @@ public:
   ) = 0;
 
   /// @brief Get the name of the library call being optimized
-  const char * getFunctionName() const { return func_name; }
+  const char *getFunctionName() const { return FunctionName; }
 
-#ifndef NDEBUG
   /// @brief Called by SimplifyLibCalls to update the occurrences statistic.
-  void succeeded() { ++occurrences; }
-#endif
-
-private:
-  const char* func_name; ///< Name of the library call we optimize
+  void succeeded() {
 #ifndef NDEBUG
-  std::string stat_name; ///< Holder for debug statistic name
-  std::string stat_desc; ///< Holder for debug statistic description
-  Statistic<> occurrences; ///< debug statistic (-debug-only=simplify-libcalls)
+    DEBUG(++occurrences);
 #endif
+  }
 };
 
-/// This class is an LLVM Pass that applies each of the LibCallOptimization 
+/// This class is an LLVM Pass that applies each of the LibCallOptimization
 /// instances to all the call sites in a module, relatively efficiently. The
-/// purpose of this pass is to provide optimizations for calls to well-known 
+/// purpose of this pass is to provide optimizations for calls to well-known
 /// functions with well-known semantics, such as those in the c library. The
-/// class provides the basic infrastructure for handling runOnModule.  Whenever /// this pass finds a function call, it asks the appropriate optimizer to 
+/// class provides the basic infrastructure for handling runOnModule.  Whenever
+/// this pass finds a function call, it asks the appropriate optimizer to
 /// validate the call (ValidateLibraryCall). If it is validated, then
 /// the OptimizeCall method is also called.
 /// @brief A ModulePass for optimizing well-known function calls.
-class SimplifyLibCalls : public ModulePass 
-{
+class SimplifyLibCalls : public ModulePass {
 public:
   /// We need some target data for accurate signature details that are
   /// target dependent. So we require target data in our AnalysisUsage.
   /// @brief Require TargetData from AnalysisUsage.
-  virtual void getAnalysisUsage(AnalysisUsage& Info) const
-  {
+  virtual void getAnalysisUsage(AnalysisUsage& Info) const {
     // Ask that the TargetData analysis be performed before us so we can use
     // the target data.
     Info.addRequired<TargetData>();
@@ -148,59 +156,59 @@ public:
   /// For this pass, process all of the function calls in the module, calling
   /// ValidateLibraryCall and OptimizeCall as appropriate.
   /// @brief Run all the lib call optimizations on a Module.
-  virtual bool runOnModule(Module &M)
-  {
+  virtual bool runOnModule(Module &M) {
     reset(M);
 
     bool result = false;
+    hash_map<std::string, LibCallOptimization*> OptznMap;
+    for (LibCallOptimization *Optzn = OptList; Optzn; Optzn = Optzn->getNext())
+      OptznMap[Optzn->getFunctionName()] = Optzn;
 
     // The call optimizations can be recursive. That is, the optimization might
     // generate a call to another function which can also be optimized. This way
-    // we make the LibCallOptimization instances very specific to the case they 
-    // handle. It also means we need to keep running over the function calls in 
+    // we make the LibCallOptimization instances very specific to the case they
+    // handle. It also means we need to keep running over the function calls in
     // the module until we don't get any more optimizations possible.
     bool found_optimization = false;
-    do
-    {
+    do {
       found_optimization = false;
-      for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI)
-      {
+      for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI) {
         // All the "well-known" functions are external and have external linkage
-        // because they live in a runtime library somewhere and were (probably) 
-        // not compiled by LLVM.  So, we only act on external functions that have 
-        // external linkage and non-empty uses.
-        if (!FI->isExternal() || !FI->hasExternalLinkage() || FI->use_empty())
+        // because they live in a runtime library somewhere and were (probably)
+        // not compiled by LLVM.  So, we only act on external functions that
+        // have external or dllimport linkage and non-empty uses.
+        if (!FI->isExternal() ||
+            !(FI->hasExternalLinkage() || FI->hasDLLImportLinkage()) ||
+            FI->use_empty())
           continue;
 
         // Get the optimization class that pertains to this function
-        LibCallOptimization* CO = optlist[FI->getName().c_str()];
-        if (!CO)
-          continue;
+        hash_map<std::string, LibCallOptimization*>::iterator OMI =
+          OptznMap.find(FI->getName());
+        if (OMI == OptznMap.end()) continue;
+        
+        LibCallOptimization *CO = OMI->second;
 
         // Make sure the called function is suitable for the optimization
-        if (!CO->ValidateCalledFunction(FI,*this))
+        if (!CO->ValidateCalledFunction(FI, *this))
           continue;
 
         // Loop over each of the uses of the function
-        for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end(); 
-             UI != UE ; )
-        {
+        for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end();
+             UI != UE ; ) {
           // If the use of the function is a call instruction
-          if (CallInst* CI = dyn_cast<CallInst>(*UI++))
-          {
+          if (CallInst* CI = dyn_cast<CallInst>(*UI++)) {
             // Do the optimization on the LibCallOptimization.
-            if (CO->OptimizeCall(CI,*this))
-            {
+            if (CO->OptimizeCall(CI, *this)) {
               ++SimplifiedLibCalls;
               found_optimization = result = true;
-#ifndef NDEBUG
               CO->succeeded();
-#endif
             }
           }
         }
       }
     } while (found_optimization);
+    
     return result;
   }
 
@@ -213,165 +221,202 @@ public:
   /// @brief Return the size_t type -- syntactic shortcut
   const Type* getIntPtrType() const { return TD->getIntPtrType(); }
 
+  /// @brief Return a Function* for the putchar libcall
+  Function* get_putchar() {
+    if (!putchar_func)
+      putchar_func = M->getOrInsertFunction("putchar", Type::IntTy, Type::IntTy,
+                                            NULL);
+    return putchar_func;
+  }
+
+  /// @brief Return a Function* for the puts libcall
+  Function* get_puts() {
+    if (!puts_func)
+      puts_func = M->getOrInsertFunction("puts", Type::IntTy,
+                                         PointerType::get(Type::SByteTy),
+                                         NULL);
+    return puts_func;
+  }
+
   /// @brief Return a Function* for the fputc libcall
-  Function* get_fputc(const Type* FILEptr_type)
-  {
+  Function* get_fputc(const Type* FILEptr_type) {
     if (!fputc_func)
-    {
-      std::vector<const Type*> args;
-      args.push_back(Type::IntTy);
-      args.push_back(FILEptr_type);
-      FunctionType* fputc_type = 
-        FunctionType::get(Type::IntTy, args, false);
-      fputc_func = M->getOrInsertFunction("fputc",fputc_type);
-    }
+      fputc_func = M->getOrInsertFunction("fputc", Type::IntTy, Type::IntTy,
+                                          FILEptr_type, NULL);
     return fputc_func;
   }
 
+  /// @brief Return a Function* for the fputs libcall
+  Function* get_fputs(const Type* FILEptr_type) {
+    if (!fputs_func)
+      fputs_func = M->getOrInsertFunction("fputs", Type::IntTy,
+                                          PointerType::get(Type::SByteTy),
+                                          FILEptr_type, NULL);
+    return fputs_func;
+  }
+
   /// @brief Return a Function* for the fwrite libcall
-  Function* get_fwrite(const Type* FILEptr_type)
-  {
+  Function* get_fwrite(const Type* FILEptr_type) {
     if (!fwrite_func)
-    {
-      std::vector<const Type*> args;
-      args.push_back(PointerType::get(Type::SByteTy));
-      args.push_back(TD->getIntPtrType());
-      args.push_back(TD->getIntPtrType());
-      args.push_back(FILEptr_type);
-      FunctionType* fwrite_type = 
-        FunctionType::get(TD->getIntPtrType(), args, false);
-      fwrite_func = M->getOrInsertFunction("fwrite",fwrite_type);
-    }
+      fwrite_func = M->getOrInsertFunction("fwrite", TD->getIntPtrType(),
+                                           PointerType::get(Type::SByteTy),
+                                           TD->getIntPtrType(),
+                                           TD->getIntPtrType(),
+                                           FILEptr_type, NULL);
     return fwrite_func;
   }
 
   /// @brief Return a Function* for the sqrt libcall
-  Function* get_sqrt()
-  {
+  Function* get_sqrt() {
     if (!sqrt_func)
-    {
-      std::vector<const Type*> args;
-      args.push_back(Type::DoubleTy);
-      FunctionType* sqrt_type = 
-        FunctionType::get(Type::DoubleTy, args, false);
-      sqrt_func = M->getOrInsertFunction("sqrt",sqrt_type);
-    }
+      sqrt_func = M->getOrInsertFunction("sqrt", Type::DoubleTy, 
+                                         Type::DoubleTy, NULL);
     return sqrt_func;
   }
 
   /// @brief Return a Function* for the strlen libcall
-  Function* get_strlen()
-  {
+  Function* get_strcpy() {
+    if (!strcpy_func)
+      strcpy_func = M->getOrInsertFunction("strcpy",
+                                           PointerType::get(Type::SByteTy),
+                                           PointerType::get(Type::SByteTy),
+                                           PointerType::get(Type::SByteTy),
+                                           NULL);
+    return strcpy_func;
+  }
+
+  /// @brief Return a Function* for the strlen libcall
+  Function* get_strlen() {
     if (!strlen_func)
-    {
-      std::vector<const Type*> args;
-      args.push_back(PointerType::get(Type::SByteTy));
-      FunctionType* strlen_type = 
-        FunctionType::get(TD->getIntPtrType(), args, false);
-      strlen_func = M->getOrInsertFunction("strlen",strlen_type);
-    }
+      strlen_func = M->getOrInsertFunction("strlen", TD->getIntPtrType(),
+                                           PointerType::get(Type::SByteTy),
+                                           NULL);
     return strlen_func;
   }
 
+  /// @brief Return a Function* for the memchr libcall
+  Function* get_memchr() {
+    if (!memchr_func)
+      memchr_func = M->getOrInsertFunction("memchr",
+                                           PointerType::get(Type::SByteTy),
+                                           PointerType::get(Type::SByteTy),
+                                           Type::IntTy, TD->getIntPtrType(),
+                                           NULL);
+    return memchr_func;
+  }
+
   /// @brief Return a Function* for the memcpy libcall
-  Function* get_memcpy()
-  {
-    if (!memcpy_func)
-    {
-      // Note: this is for llvm.memcpy intrinsic
-      std::vector<const Type*> args;
-      args.push_back(PointerType::get(Type::SByteTy));
-      args.push_back(PointerType::get(Type::SByteTy));
-      args.push_back(Type::IntTy);
-      args.push_back(Type::IntTy);
-      FunctionType* memcpy_type = FunctionType::get(Type::VoidTy, args, false);
-      memcpy_func = M->getOrInsertFunction("llvm.memcpy",memcpy_type);
+  Function* get_memcpy() {
+    if (!memcpy_func) {
+      const Type *SBP = PointerType::get(Type::SByteTy);
+      const char *N = TD->getIntPtrType() == Type::UIntTy ?
+                            "llvm.memcpy.i32" : "llvm.memcpy.i64";
+      memcpy_func = M->getOrInsertFunction(N, Type::VoidTy, SBP, SBP,
+                                           TD->getIntPtrType(), Type::UIntTy,
+                                           NULL);
     }
     return memcpy_func;
   }
 
+  Function *getUnaryFloatFunction(const char *Name, Function *&Cache) {
+    if (!Cache)
+      Cache = M->getOrInsertFunction(Name, Type::FloatTy, Type::FloatTy, NULL);
+    return Cache;
+  }
+  
+  Function *get_floorf() { return getUnaryFloatFunction("floorf", floorf_func);}
+  Function *get_ceilf()  { return getUnaryFloatFunction( "ceilf",  ceilf_func);}
+  Function *get_roundf() { return getUnaryFloatFunction("roundf", roundf_func);}
+  Function *get_rintf()  { return getUnaryFloatFunction( "rintf",  rintf_func);}
+  Function *get_nearbyintf() { return getUnaryFloatFunction("nearbyintf",
+                                                            nearbyintf_func); }
 private:
   /// @brief Reset our cached data for a new Module
-  void reset(Module& mod)
-  {
+  void reset(Module& mod) {
     M = &mod;
     TD = &getAnalysis<TargetData>();
+    putchar_func = 0;
+    puts_func = 0;
     fputc_func = 0;
+    fputs_func = 0;
     fwrite_func = 0;
     memcpy_func = 0;
+    memchr_func = 0;
     sqrt_func   = 0;
+    strcpy_func = 0;
     strlen_func = 0;
+    floorf_func = 0;
+    ceilf_func = 0;
+    roundf_func = 0;
+    rintf_func = 0;
+    nearbyintf_func = 0;
   }
 
 private:
-  Function* fputc_func;  ///< Cached fputc function
-  Function* fwrite_func; ///< Cached fwrite function
-  Function* memcpy_func; ///< Cached llvm.memcpy function
-  Function* sqrt_func;   ///< Cached sqrt function
-  Function* strlen_func; ///< Cached strlen function
-  Module* M;             ///< Cached Module
-  TargetData* TD;        ///< Cached TargetData
+  /// Caches for function pointers.
+  Function *putchar_func, *puts_func;
+  Function *fputc_func, *fputs_func, *fwrite_func;
+  Function *memcpy_func, *memchr_func;
+  Function* sqrt_func;
+  Function *strcpy_func, *strlen_func;
+  Function *floorf_func, *ceilf_func, *roundf_func;
+  Function *rintf_func, *nearbyintf_func;
+  Module *M;             ///< Cached Module
+  TargetData *TD;        ///< Cached TargetData
 };
 
 // Register the pass
-RegisterOpt<SimplifyLibCalls> 
-X("simplify-libcalls","Simplify well-known library calls");
+RegisterPass<SimplifyLibCalls>
+X("simplify-libcalls", "Simplify well-known library calls");
 
 } // anonymous namespace
 
 // The only public symbol in this file which just instantiates the pass object
-ModulePass *llvm::createSimplifyLibCallsPass() 
-{ 
-  return new SimplifyLibCalls(); 
+ModulePass *llvm::createSimplifyLibCallsPass() {
+  return new SimplifyLibCalls();
 }
 
 // Classes below here, in the anonymous namespace, are all subclasses of the
 // LibCallOptimization class, each implementing all optimizations possible for a
 // single well-known library call. Each has a static singleton instance that
-// auto registers it into the "optlist" global above. 
+// auto registers it into the "optlist" global above.
 namespace {
 
-// Forward declare a utility function.
+// Forward declare utility functions.
 bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** A = 0 );
+Value *CastToCStr(Value *V, Instruction &IP);
 
 /// This LibCallOptimization will find instances of a call to "exit" that occurs
 /// within the "main" function and change it to a simple "ret" instruction with
 /// the same value passed to the exit function. When this is done, it splits the
 /// basic block at the exit(3) call and deletes the call instruction.
 /// @brief Replace calls to exit in main with a simple return
-struct ExitInMainOptimization : public LibCallOptimization
-{
-  ExitInMainOptimization() : LibCallOptimization("exit") {}
-  virtual ~ExitInMainOptimization() {}
+struct ExitInMainOptimization : public LibCallOptimization {
+  ExitInMainOptimization() : LibCallOptimization("exit",
+      "Number of 'exit' calls simplified") {}
 
   // Make sure the called function looks like exit (int argument, int return
-  // type, external linkage, not varargs). 
-  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
-  {
-    if (f->arg_size() >= 1)
-      if (f->arg_begin()->getType()->isInteger())
-        return true;
-    return false;
+  // type, external linkage, not varargs).
+  virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+    return F->arg_size() >= 1 && F->arg_begin()->getType()->isInteger();
   }
 
-  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
-  {
+  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
     // To be careful, we check that the call to exit is coming from "main", that
     // main has external linkage, and the return type of main and the argument
-    // to exit have the same type. 
+    // to exit have the same type.
     Function *from = ci->getParent()->getParent();
     if (from->hasExternalLinkage())
       if (from->getReturnType() == ci->getOperand(1)->getType())
-        if (from->getName() == "main")
-        {
-          // Okay, time to actually do the optimization. First, get the basic 
+        if (from->getName() == "main") {
+          // Okay, time to actually do the optimization. First, get the basic
           // block of the call instruction
           BasicBlock* bb = ci->getParent();
 
-          // Create a return instruction that we'll replace the call with. 
-          // Note that the argument of the return is the argument of the call 
+          // Create a return instruction that we'll replace the call with.
+          // Note that the argument of the return is the argument of the call
           // instruction.
-          ReturnInst* ri = new ReturnInst(ci->getOperand(1), ci);
+          new ReturnInst(ci->getOperand(1), ci);
 
           // Split the block at the call instruction which places it in a new
           // basic block.
@@ -395,28 +440,25 @@ struct ExitInMainOptimization : public LibCallOptimization
   }
 } ExitInMainOptimizer;
 
-/// This LibCallOptimization will simplify a call to the strcat library 
-/// function. The simplification is possible only if the string being 
-/// concatenated is a constant array or a constant expression that results in 
-/// a constant string. In this case we can replace it with strlen + llvm.memcpy 
+/// This LibCallOptimization will simplify a call to the strcat library
+/// function. The simplification is possible only if the string being
+/// concatenated is a constant array or a constant expression that results in
+/// a constant string. In this case we can replace it with strlen + llvm.memcpy
 /// of the constant string. Both of these calls are further reduced, if possible
 /// on subsequent passes.
 /// @brief Simplify the strcat library function.
-struct StrCatOptimization : public LibCallOptimization
-{
+struct StrCatOptimization : public LibCallOptimization {
 public:
   /// @brief Default constructor
-  StrCatOptimization() : LibCallOptimization("strcat") {}
+  StrCatOptimization() : LibCallOptimization("strcat",
+      "Number of 'strcat' calls simplified") {}
 
 public:
-  /// @breif  Destructor
-  virtual ~StrCatOptimization() {}
 
   /// @brief Make sure that the "strcat" function has the right prototype
-  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC) 
-  {
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
     if (f->getReturnType() == PointerType::get(Type::SByteTy))
-      if (f->arg_size() == 2) 
+      if (f->arg_size() == 2)
       {
         Function::const_arg_iterator AI = f->arg_begin();
         if (AI++->getType() == PointerType::get(Type::SByteTy))
@@ -430,14 +472,12 @@ public:
   }
 
   /// @brief Optimize the strcat library function
-  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
-  {
+  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
     // Extract some information from the instruction
-    Module* M = ci->getParent()->getParent()->getParent();
     Value* dest = ci->getOperand(1);
     Value* src  = ci->getOperand(2);
 
-    // Extract the initializer (while making numerous checks) from the 
+    // Extract the initializer (while making numerous checks) from the
     // source operand of the call to strcat. If we get null back, one of
     // a variety of checks in get_GVInitializer failed
     uint64_t len = 0;
@@ -445,8 +485,7 @@ public:
       return false;
 
     // Handle the simple, do-nothing case
-    if (len == 0)
-    {
+    if (len == 0) {
       ci->replaceAllUsesWith(dest);
       ci->eraseFromParent();
       return true;
@@ -456,19 +495,19 @@ public:
     // terminator as well.
     len++;
 
-    // We need to find the end of the destination string.  That's where the 
-    // memory is to be moved to. We just generate a call to strlen (further 
-    // optimized in another pass).  Note that the SLC.get_strlen() call 
+    // We need to find the end of the destination string.  That's where the
+    // memory is to be moved to. We just generate a call to strlen (further
+    // optimized in another pass).  Note that the SLC.get_strlen() call
     // caches the Function* for us.
-    CallInst* strlen_inst = 
+    CallInst* strlen_inst =
       new CallInst(SLC.get_strlen(), dest, dest->getName()+".len",ci);
 
-    // Now that we have the destination's length, we must index into the 
+    // Now that we have the destination's length, we must index into the
     // destination's pointer to get the actual memcpy destination (end of
     // the string .. we're concatenating).
     std::vector<Value*> idx;
     idx.push_back(strlen_inst);
-    GetElementPtrInst* gep = 
+    GetElementPtrInst* gep =
       new GetElementPtrInst(dest,idx,dest->getName()+".indexed",ci);
 
     // We have enough information to now generate the memcpy call to
@@ -476,12 +515,12 @@ public:
     std::vector<Value*> vals;
     vals.push_back(gep); // destination
     vals.push_back(ci->getOperand(2)); // source
-    vals.push_back(ConstantSInt::get(Type::IntTy,len)); // length
-    vals.push_back(ConstantSInt::get(Type::IntTy,1)); // alignment
+    vals.push_back(ConstantInt::get(SLC.getIntPtrType(),len)); // length
+    vals.push_back(ConstantInt::get(Type::UIntTy,1)); // alignment
     new CallInst(SLC.get_memcpy(), vals, "", ci);
 
-    // Finally, substitute the first operand of the strcat call for the 
-    // strcat call itself since strcat returns its first operand; and, 
+    // Finally, substitute the first operand of the strcat call for the
+    // strcat call itself since strcat returns its first operand; and,
     // kill the strcat CallInst.
     ci->replaceAllUsesWith(dest);
     ci->eraseFromParent();
@@ -489,37 +528,110 @@ public:
   }
 } StrCatOptimizer;
 
-/// This LibCallOptimization will simplify a call to the strcmp library 
-/// function.  It optimizes out cases where one or both arguments are constant
+/// This LibCallOptimization will simplify a call to the strchr library
+/// function.  It optimizes out cases where the arguments are both constant
 /// and the result can be determined statically.
 /// @brief Simplify the strcmp library function.
-struct StrCmpOptimization : public LibCallOptimization
-{
+struct StrChrOptimization : public LibCallOptimization {
 public:
-  StrCmpOptimization() : LibCallOptimization("strcmp") {}
-  virtual ~StrCmpOptimization() {}
+  StrChrOptimization() : LibCallOptimization("strchr",
+      "Number of 'strchr' calls simplified") {}
 
-  /// @brief Make sure that the "strcpy" function has the right prototype
-  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC) 
-  {
-    if (f->getReturnType() == Type::IntTy && f->arg_size() == 2)
+  /// @brief Make sure that the "strchr" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
+    if (f->getReturnType() == PointerType::get(Type::SByteTy) &&
+        f->arg_size() == 2)
       return true;
     return false;
   }
 
-  /// @brief Perform the strcpy optimization
-  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
-  {
+  /// @brief Perform the strchr optimizations
+  virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
+    // If there aren't three operands, bail
+    if (ci->getNumOperands() != 3)
+      return false;
+
+    // Check that the first argument to strchr is a constant array of sbyte.
+    // If it is, get the length and data, otherwise return false.
+    uint64_t len = 0;
+    ConstantArray* CA = 0;
+    if (!getConstantStringLength(ci->getOperand(1),len,&CA))
+      return false;
+
+    // Check that the second argument to strchr is a constant int. If it isn't
+    // a constant signed integer, we can try an alternate optimization
+    ConstantInt* CSI = dyn_cast<ConstantInt>(ci->getOperand(2));
+    if (!CSI || CSI->getType()->isUnsigned() ) {
+      // The second operand is not constant, or not signed. Just lower this to 
+      // memchr since we know the length of the string since it is constant.
+      Function* f = SLC.get_memchr();
+      std::vector<Value*> args;
+      args.push_back(ci->getOperand(1));
+      args.push_back(ci->getOperand(2));
+      args.push_back(ConstantInt::get(SLC.getIntPtrType(),len));
+      ci->replaceAllUsesWith( new CallInst(f,args,ci->getName(),ci));
+      ci->eraseFromParent();
+      return true;
+    }
+
+    // Get the character we're looking for
+    int64_t chr = CSI->getSExtValue();
+
+    // Compute the offset
+    uint64_t offset = 0;
+    bool char_found = false;
+    for (uint64_t i = 0; i < len; ++i) {
+      if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i))) {
+        // Check for the null terminator
+        if (CI->isNullValue())
+          break; // we found end of string
+        else if (CI->getSExtValue() == chr) {
+          char_found = true;
+          offset = i;
+          break;
+        }
+      }
+    }
+
+    // strchr(s,c)  -> offset_of_in(c,s)
+    //    (if c is a constant integer and s is a constant string)
+    if (char_found) {
+      std::vector<Value*> indices;
+      indices.push_back(ConstantInt::get(Type::ULongTy,offset));
+      GetElementPtrInst* GEP = new GetElementPtrInst(ci->getOperand(1),indices,
+          ci->getOperand(1)->getName()+".strchr",ci);
+      ci->replaceAllUsesWith(GEP);
+    } else {
+      ci->replaceAllUsesWith(
+          ConstantPointerNull::get(PointerType::get(Type::SByteTy)));
+    }
+    ci->eraseFromParent();
+    return true;
+  }
+} StrChrOptimizer;
+
+/// This LibCallOptimization will simplify a call to the strcmp library
+/// function.  It optimizes out cases where one or both arguments are constant
+/// and the result can be determined statically.
+/// @brief Simplify the strcmp library function.
+struct StrCmpOptimization : public LibCallOptimization {
+public:
+  StrCmpOptimization() : LibCallOptimization("strcmp",
+      "Number of 'strcmp' calls simplified") {}
+
+  /// @brief Make sure that the "strcmp" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+    return F->getReturnType() == Type::IntTy && F->arg_size() == 2;
+  }
+
+  /// @brief Perform the strcmp optimization
+  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
     // First, check to see if src and destination are the same. If they are,
-    // then the optimization is to replace the CallInst with the destination
-    // because the call is a no-op. Note that this corresponds to the 
-    // degenerate strcpy(X,X) case which should have "undefined" results
-    // according to the C specification. However, it occurs sometimes and
-    // we optimize it as a no-op.
+    // then the optimization is to replace the CallInst with a constant 0
+    // because the call is a no-op.
     Value* s1 = ci->getOperand(1);
     Value* s2 = ci->getOperand(2);
-    if (s1 == s2)
-    {
+    if (s1 == s2) {
       // strcmp(x,x)  -> 0
       ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,0));
       ci->eraseFromParent();
@@ -529,15 +641,15 @@ public:
     bool isstr_1 = false;
     uint64_t len_1 = 0;
     ConstantArray* A1;
-    if (getConstantStringLength(s1,len_1,&A1))
-    {
+    if (getConstantStringLength(s1,len_1,&A1)) {
       isstr_1 = true;
-      if (len_1 == 0)
-      {
+      if (len_1 == 0) {
         // strcmp("",x) -> *x
-        LoadInst* load = new LoadInst(s1,ci->getName()+".load",ci);
-        CastInst* cast = 
-          new CastInst(load,Type::IntTy,ci->getName()+".int",ci);
+        LoadInst* load =
+          new LoadInst(CastToCStr(s2,*ci), ci->getName()+".load",ci);
+        CastInst* cast =
+          CastInst::create(Instruction::SExt, load, Type::IntTy, 
+                           ci->getName()+".int", ci);
         ci->replaceAllUsesWith(cast);
         ci->eraseFromParent();
         return true;
@@ -547,28 +659,27 @@ public:
     bool isstr_2 = false;
     uint64_t len_2 = 0;
     ConstantArray* A2;
-    if (getConstantStringLength(s2,len_2,&A2))
-    {
+    if (getConstantStringLength(s2, len_2, &A2)) {
       isstr_2 = true;
-      if (len_2 == 0)
-      {
+      if (len_2 == 0) {
         // strcmp(x,"") -> *x
-        LoadInst* load = new LoadInst(s2,ci->getName()+".val",ci);
-        CastInst* cast = 
-          new CastInst(load,Type::IntTy,ci->getName()+".int",ci);
+        LoadInst* load =
+          new LoadInst(CastToCStr(s1,*ci),ci->getName()+".val",ci);
+        CastInst* cast =
+          CastInst::create(Instruction::SExt, load, Type::IntTy, 
+                           ci->getName()+".int", ci);
         ci->replaceAllUsesWith(cast);
         ci->eraseFromParent();
         return true;
       }
     }
 
-    if (isstr_1 && isstr_2)
-    {
+    if (isstr_1 && isstr_2) {
       // strcmp(x,y)  -> cnst  (if both x and y are constant strings)
       std::string str1 = A1->getAsString();
       std::string str2 = A2->getAsString();
       int result = strcmp(str1.c_str(), str2.c_str());
-      ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,result));
+      ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,result));
       ci->eraseFromParent();
       return true;
     }
@@ -576,27 +687,115 @@ public:
   }
 } StrCmpOptimizer;
 
-/// This LibCallOptimization will simplify a call to the strcpy library 
-/// function.  Two optimizations are possible: 
+/// This LibCallOptimization will simplify a call to the strncmp library
+/// function.  It optimizes out cases where one or both arguments are constant
+/// and the result can be determined statically.
+/// @brief Simplify the strncmp library function.
+struct StrNCmpOptimization : public LibCallOptimization {
+public:
+  StrNCmpOptimization() : LibCallOptimization("strncmp",
+      "Number of 'strncmp' calls simplified") {}
+
+  /// @brief Make sure that the "strncmp" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
+    if (f->getReturnType() == Type::IntTy && f->arg_size() == 3)
+      return true;
+    return false;
+  }
+
+  /// @brief Perform the strncpy optimization
+  virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
+    // First, check to see if src and destination are the same. If they are,
+    // then the optimization is to replace the CallInst with a constant 0
+    // because the call is a no-op.
+    Value* s1 = ci->getOperand(1);
+    Value* s2 = ci->getOperand(2);
+    if (s1 == s2) {
+      // strncmp(x,x,l)  -> 0
+      ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,0));
+      ci->eraseFromParent();
+      return true;
+    }
+
+    // Check the length argument, if it is Constant zero then the strings are
+    // considered equal.
+    uint64_t len_arg = 0;
+    bool len_arg_is_const = false;
+    if (ConstantInt* len_CI = dyn_cast<ConstantInt>(ci->getOperand(3))) {
+      len_arg_is_const = true;
+      len_arg = len_CI->getZExtValue();
+      if (len_arg == 0) {
+        // strncmp(x,y,0)   -> 0
+        ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,0));
+        ci->eraseFromParent();
+        return true;
+      }
+    }
+
+    bool isstr_1 = false;
+    uint64_t len_1 = 0;
+    ConstantArray* A1;
+    if (getConstantStringLength(s1, len_1, &A1)) {
+      isstr_1 = true;
+      if (len_1 == 0) {
+        // strncmp("",x) -> *x
+        LoadInst* load = new LoadInst(s1,ci->getName()+".load",ci);
+        CastInst* cast =
+          CastInst::create(Instruction::SExt, load, Type::IntTy, 
+                           ci->getName()+".int", ci);
+        ci->replaceAllUsesWith(cast);
+        ci->eraseFromParent();
+        return true;
+      }
+    }
+
+    bool isstr_2 = false;
+    uint64_t len_2 = 0;
+    ConstantArray* A2;
+    if (getConstantStringLength(s2,len_2,&A2)) {
+      isstr_2 = true;
+      if (len_2 == 0) {
+        // strncmp(x,"") -> *x
+        LoadInst* load = new LoadInst(s2,ci->getName()+".val",ci);
+        CastInst* cast =
+          CastInst::create(Instruction::SExt, load, Type::IntTy, 
+                           ci->getName()+".int", ci);
+        ci->replaceAllUsesWith(cast);
+        ci->eraseFromParent();
+        return true;
+      }
+    }
+
+    if (isstr_1 && isstr_2 && len_arg_is_const) {
+      // strncmp(x,y,const) -> constant
+      std::string str1 = A1->getAsString();
+      std::string str2 = A2->getAsString();
+      int result = strncmp(str1.c_str(), str2.c_str(), len_arg);
+      ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,result));
+      ci->eraseFromParent();
+      return true;
+    }
+    return false;
+  }
+} StrNCmpOptimizer;
+
+/// This LibCallOptimization will simplify a call to the strcpy library
+/// function.  Two optimizations are possible:
 /// (1) If src and dest are the same and not volatile, just return dest
 /// (2) If the src is a constant then we can convert to llvm.memmove
 /// @brief Simplify the strcpy library function.
-struct StrCpyOptimization : public LibCallOptimization
-{
+struct StrCpyOptimization : public LibCallOptimization {
 public:
-  StrCpyOptimization() : LibCallOptimization("strcpy") {}
-  virtual ~StrCpyOptimization() {}
+  StrCpyOptimization() : LibCallOptimization("strcpy",
+      "Number of 'strcpy' calls simplified") {}
 
   /// @brief Make sure that the "strcpy" function has the right prototype
-  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC) 
-  {
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
     if (f->getReturnType() == PointerType::get(Type::SByteTy))
-      if (f->arg_size() == 2) 
-      {
+      if (f->arg_size() == 2) {
         Function::const_arg_iterator AI = f->arg_begin();
         if (AI++->getType() == PointerType::get(Type::SByteTy))
-          if (AI->getType() == PointerType::get(Type::SByteTy))
-          {
+          if (AI->getType() == PointerType::get(Type::SByteTy)) {
             // Indicate this is a suitable call type.
             return true;
           }
@@ -605,23 +804,21 @@ public:
   }
 
   /// @brief Perform the strcpy optimization
-  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
-  {
+  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
     // First, check to see if src and destination are the same. If they are,
     // then the optimization is to replace the CallInst with the destination
-    // because the call is a no-op. Note that this corresponds to the 
+    // because the call is a no-op. Note that this corresponds to the
     // degenerate strcpy(X,X) case which should have "undefined" results
     // according to the C specification. However, it occurs sometimes and
     // we optimize it as a no-op.
     Value* dest = ci->getOperand(1);
     Value* src = ci->getOperand(2);
-    if (dest == src)
-    {
+    if (dest == src) {
       ci->replaceAllUsesWith(dest);
       ci->eraseFromParent();
       return true;
     }
-    
+
     // Get the length of the constant string referenced by the second operand,
     // the "src" parameter. Fail the optimization if we can't get the length
     // (note that getConstantStringLength does lots of checks to make sure this
@@ -632,8 +829,7 @@ public:
 
     // If the constant string's length is zero we can optimize this by just
     // doing a store of 0 at the first byte of the destination
-    if (len == 0)
-    {
+    if (len == 0) {
       new StoreInst(ConstantInt::get(Type::SByteTy,0),ci->getOperand(1),ci);
       ci->replaceAllUsesWith(dest);
       ci->eraseFromParent();
@@ -644,20 +840,17 @@ public:
     // terminator as well.
     len++;
 
-    // Extract some information from the instruction
-    Module* M = ci->getParent()->getParent()->getParent();
-
     // We have enough information to now generate the memcpy call to
     // do the concatenation for us.
     std::vector<Value*> vals;
     vals.push_back(dest); // destination
     vals.push_back(src); // source
-    vals.push_back(ConstantSInt::get(Type::IntTy,len)); // length
-    vals.push_back(ConstantSInt::get(Type::IntTy,1)); // alignment
+    vals.push_back(ConstantInt::get(SLC.getIntPtrType(),len)); // length
+    vals.push_back(ConstantInt::get(Type::UIntTy,1)); // alignment
     new CallInst(SLC.get_memcpy(), vals, "", ci);
 
-    // Finally, substitute the first operand of the strcat call for the 
-    // strcat call itself since strcat returns its first operand; and, 
+    // Finally, substitute the first operand of the strcat call for the
+    // strcat call itself since strcat returns its first operand; and,
     // kill the strcat CallInst.
     ci->replaceAllUsesWith(dest);
     ci->eraseFromParent();
@@ -665,20 +858,19 @@ public:
   }
 } StrCpyOptimizer;
 
-/// This LibCallOptimization will simplify a call to the strlen library 
-/// function by replacing it with a constant value if the string provided to 
+/// This LibCallOptimization will simplify a call to the strlen library
+/// function by replacing it with a constant value if the string provided to
 /// it is a constant array.
 /// @brief Simplify the strlen library function.
-struct StrLenOptimization : public LibCallOptimization
-{
-  StrLenOptimization() : LibCallOptimization("strlen") {}
-  virtual ~StrLenOptimization() {}
+struct StrLenOptimization : public LibCallOptimization {
+  StrLenOptimization() : LibCallOptimization("strlen",
+      "Number of 'strlen' calls simplified") {}
 
   /// @brief Make sure that the "strlen" function has the right prototype
   virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
   {
     if (f->getReturnType() == SLC.getTargetData()->getIntPtrType())
-      if (f->arg_size() == 1) 
+      if (f->arg_size() == 1)
         if (Function::const_arg_iterator AI = f->arg_begin())
           if (AI->getType() == PointerType::get(Type::SByteTy))
             return true;
@@ -688,37 +880,187 @@ struct StrLenOptimization : public LibCallOptimization
   /// @brief Perform the strlen optimization
   virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
   {
-    // Get the length of the string
+    // Make sure we're dealing with an sbyte* here.
+    Value* str = ci->getOperand(1);
+    if (str->getType() != PointerType::get(Type::SByteTy))
+      return false;
+
+    // Does the call to strlen have exactly one use?
+    if (ci->hasOneUse())
+      // Is that single use a icmp operator?
+      if (ICmpInst* bop = dyn_cast<ICmpInst>(ci->use_back()))
+        // Is it compared against a constant integer?
+        if (ConstantInt* CI = dyn_cast<ConstantInt>(bop->getOperand(1)))
+        {
+          // Get the value the strlen result is compared to
+          uint64_t val = CI->getZExtValue();
+
+          // If its compared against length 0 with == or !=
+          if (val == 0 &&
+              (bop->getPredicate() == ICmpInst::ICMP_EQ ||
+               bop->getPredicate() == ICmpInst::ICMP_NE))
+          {
+            // strlen(x) != 0 -> *x != 0
+            // strlen(x) == 0 -> *x == 0
+            LoadInst* load = new LoadInst(str,str->getName()+".first",ci);
+            ICmpInst* rbop = new ICmpInst(bop->getPredicate(), load, 
+                                          ConstantInt::get(Type::SByteTy,0),
+                                          bop->getName()+".strlen", ci);
+            bop->replaceAllUsesWith(rbop);
+            bop->eraseFromParent();
+            ci->eraseFromParent();
+            return true;
+          }
+        }
+
+    // Get the length of the constant string operand
     uint64_t len = 0;
     if (!getConstantStringLength(ci->getOperand(1),len))
       return false;
 
-    ci->replaceAllUsesWith(
-        ConstantInt::get(SLC.getTargetData()->getIntPtrType(),len));
+    // strlen("xyz") -> 3 (for example)
+    const Type *Ty = SLC.getTargetData()->getIntPtrType();
+    ci->replaceAllUsesWith(ConstantInt::get(Ty, len));
+     
     ci->eraseFromParent();
     return true;
   }
 } StrLenOptimizer;
 
-/// This LibCallOptimization will simplify a call to the memcpy library 
-/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8 
+/// IsOnlyUsedInEqualsComparison - Return true if it only matters that the value
+/// is equal or not-equal to zero. 
+static bool IsOnlyUsedInEqualsZeroComparison(Instruction *I) {
+  for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+       UI != E; ++UI) {
+    Instruction *User = cast<Instruction>(*UI);
+    if (ICmpInst *IC = dyn_cast<ICmpInst>(User)) {
+      if ((IC->getPredicate() == ICmpInst::ICMP_NE ||
+           IC->getPredicate() == ICmpInst::ICMP_EQ) &&
+          isa<Constant>(IC->getOperand(1)) &&
+          cast<Constant>(IC->getOperand(1))->isNullValue())
+        continue;
+    } else if (CastInst *CI = dyn_cast<CastInst>(User))
+      if (CI->getType() == Type::BoolTy)
+        continue;
+    // Unknown instruction.
+    return false;
+  }
+  return true;
+}
+
+/// This memcmpOptimization will simplify a call to the memcmp library
+/// function.
+struct memcmpOptimization : public LibCallOptimization {
+  /// @brief Default Constructor
+  memcmpOptimization()
+    : LibCallOptimization("memcmp", "Number of 'memcmp' calls simplified") {}
+  
+  /// @brief Make sure that the "memcmp" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
+    Function::const_arg_iterator AI = F->arg_begin();
+    if (F->arg_size() != 3 || !isa<PointerType>(AI->getType())) return false;
+    if (!isa<PointerType>((++AI)->getType())) return false;
+    if (!(++AI)->getType()->isInteger()) return false;
+    if (!F->getReturnType()->isInteger()) return false;
+    return true;
+  }
+  
+  /// Because of alignment and instruction information that we don't have, we
+  /// leave the bulk of this to the code generators.
+  ///
+  /// Note that we could do much more if we could force alignment on otherwise
+  /// small aligned allocas, or if we could indicate that loads have a small
+  /// alignment.
+  virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &TD) {
+    Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
+
+    // If the two operands are the same, return zero.
+    if (LHS == RHS) {
+      // memcmp(s,s,x) -> 0
+      CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
+      CI->eraseFromParent();
+      return true;
+    }
+    
+    // Make sure we have a constant length.
+    ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getOperand(3));
+    if (!LenC) return false;
+    uint64_t Len = LenC->getZExtValue();
+      
+    // If the length is zero, this returns 0.
+    switch (Len) {
+    case 0:
+      // memcmp(s1,s2,0) -> 0
+      CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
+      CI->eraseFromParent();
+      return true;
+    case 1: {
+      // memcmp(S1,S2,1) -> *(ubyte*)S1 - *(ubyte*)S2
+      const Type *UCharPtr = PointerType::get(Type::UByteTy);
+      CastInst *Op1Cast = CastInst::create(
+          Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
+      CastInst *Op2Cast = CastInst::create(
+          Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
+      Value *S1V = new LoadInst(Op1Cast, LHS->getName()+".val", CI);
+      Value *S2V = new LoadInst(Op2Cast, RHS->getName()+".val", CI);
+      Value *RV = BinaryOperator::createSub(S1V, S2V, CI->getName()+".diff",CI);
+      if (RV->getType() != CI->getType())
+        RV = CastInst::createIntegerCast(RV, CI->getType(), false, 
+                                         RV->getName(), CI);
+      CI->replaceAllUsesWith(RV);
+      CI->eraseFromParent();
+      return true;
+    }
+    case 2:
+      if (IsOnlyUsedInEqualsZeroComparison(CI)) {
+        // TODO: IF both are aligned, use a short load/compare.
+      
+        // memcmp(S1,S2,2) -> S1[0]-S2[0] | S1[1]-S2[1] iff only ==/!= 0 matters
+        const Type *UCharPtr = PointerType::get(Type::UByteTy);
+        CastInst *Op1Cast = CastInst::create(
+            Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
+        CastInst *Op2Cast = CastInst::create(
+            Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
+        Value *S1V1 = new LoadInst(Op1Cast, LHS->getName()+".val1", CI);
+        Value *S2V1 = new LoadInst(Op2Cast, RHS->getName()+".val1", CI);
+        Value *D1 = BinaryOperator::createSub(S1V1, S2V1,
+                                              CI->getName()+".d1", CI);
+        Constant *One = ConstantInt::get(Type::IntTy, 1);
+        Value *G1 = new GetElementPtrInst(Op1Cast, One, "next1v", CI);
+        Value *G2 = new GetElementPtrInst(Op2Cast, One, "next2v", CI);
+        Value *S1V2 = new LoadInst(G1, LHS->getName()+".val2", CI);
+        Value *S2V2 = new LoadInst(G2, RHS->getName()+".val2", CI);
+        Value *D2 = BinaryOperator::createSub(S1V2, S2V2,
+                                              CI->getName()+".d1", CI);
+        Value *Or = BinaryOperator::createOr(D1, D2, CI->getName()+".res", CI);
+        if (Or->getType() != CI->getType())
+          Or = CastInst::createIntegerCast(Or, CI->getType(), false /*ZExt*/, 
+                                           Or->getName(), CI);
+        CI->replaceAllUsesWith(Or);
+        CI->eraseFromParent();
+        return true;
+      }
+      break;
+    default:
+      break;
+    }
+    
+    return false;
+  }
+} memcmpOptimizer;
+
+
+/// This LibCallOptimization will simplify a call to the memcpy library
+/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
 /// bytes depending on the length of the string and the alignment. Additional
 /// optimizations are possible in code generation (sequence of immediate store)
 /// @brief Simplify the memcpy library function.
-struct MemCpyOptimization : public LibCallOptimization
-{
-  /// @brief Default Constructor
-  MemCpyOptimization() : LibCallOptimization("llvm.memcpy") {}
-protected:
-  /// @brief Subclass Constructor 
-  MemCpyOptimization(const char* fname) : LibCallOptimization(fname) {}
-public:
-  /// @brief Destructor
-  virtual ~MemCpyOptimization() {}
+struct LLVMMemCpyMoveOptzn : public LibCallOptimization {
+  LLVMMemCpyMoveOptzn(const char* fname, const char* desc)
+  : LibCallOptimization(fname, desc) {}
 
   /// @brief Make sure that the "memcpy" function has the right prototype
-  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD)
-  {
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD) {
     // Just make sure this has 4 arguments per LLVM spec.
     return (f->arg_size() == 4);
   }
@@ -729,8 +1071,7 @@ public:
   /// alignment match the sizes of our intrinsic types so we can do a load and
   /// store instead of the memcpy call.
   /// @brief Perform the memcpy optimization.
-  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& TD)
-  {
+  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& TD) {
     // Make sure we have constant int values to work with
     ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
     if (!LEN)
@@ -740,8 +1081,10 @@ public:
       return false;
 
     // If the length is larger than the alignment, we can't optimize
-    uint64_t len = LEN->getRawValue();
-    uint64_t alignment = ALIGN->getRawValue();
+    uint64_t len = LEN->getZExtValue();
+    uint64_t alignment = ALIGN->getZExtValue();
+    if (alignment == 0)
+      alignment = 1; // Alignment 0 is identity for alignment 1
     if (len > alignment)
       return false;
 
@@ -764,93 +1107,181 @@ public:
     }
 
     // Cast source and dest to the right sized primitive and then load/store
-    CastInst* SrcCast = 
-      new CastInst(src,PointerType::get(castType),src->getName()+".cast",ci);
-    CastInst* DestCast = 
-      new CastInst(dest,PointerType::get(castType),dest->getName()+".cast",ci);
+    CastInst* SrcCast = CastInst::create(Instruction::BitCast,
+        src, PointerType::get(castType), src->getName()+".cast", ci);
+    CastInst* DestCast = CastInst::create(Instruction::BitCast,
+        dest, PointerType::get(castType),dest->getName()+".cast", ci);
     LoadInst* LI = new LoadInst(SrcCast,SrcCast->getName()+".val",ci);
-    StoreInst* SI = new StoreInst(LI, DestCast, ci);
+    new StoreInst(LI, DestCast, ci);
     ci->eraseFromParent();
     return true;
   }
-} MemCpyOptimizer;
+};
 
-/// This LibCallOptimization will simplify a call to the memmove library 
-/// function. It is identical to MemCopyOptimization except for the name of 
-/// the intrinsic.
-/// @brief Simplify the memmove library function.
-struct MemMoveOptimization : public MemCpyOptimization
-{
+/// This LibCallOptimization will simplify a call to the memcpy/memmove library
+/// functions.
+LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer32("llvm.memcpy.i32",
+                                    "Number of 'llvm.memcpy' calls simplified");
+LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer64("llvm.memcpy.i64",
+                                   "Number of 'llvm.memcpy' calls simplified");
+LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer32("llvm.memmove.i32",
+                                   "Number of 'llvm.memmove' calls simplified");
+LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer64("llvm.memmove.i64",
+                                   "Number of 'llvm.memmove' calls simplified");
+
+/// This LibCallOptimization will simplify a call to the memset library
+/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
+/// bytes depending on the length argument.
+struct LLVMMemSetOptimization : public LibCallOptimization {
   /// @brief Default Constructor
-  MemMoveOptimization() : MemCpyOptimization("llvm.memmove") {}
+  LLVMMemSetOptimization(const char *Name) : LibCallOptimization(Name,
+      "Number of 'llvm.memset' calls simplified") {}
+
+  /// @brief Make sure that the "memset" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
+    // Just make sure this has 3 arguments per LLVM spec.
+    return F->arg_size() == 4;
+  }
+
+  /// Because of alignment and instruction information that we don't have, we
+  /// leave the bulk of this to the code generators. The optimization here just
+  /// deals with a few degenerate cases where the length parameter is constant
+  /// and the alignment matches the sizes of our intrinsic types so we can do
+  /// store instead of the memcpy call. Other calls are transformed into the
+  /// llvm.memset intrinsic.
+  /// @brief Perform the memset optimization.
+  virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &TD) {
+    // Make sure we have constant int values to work with
+    ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
+    if (!LEN)
+      return false;
+    ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
+    if (!ALIGN)
+      return false;
+
+    // Extract the length and alignment
+    uint64_t len = LEN->getZExtValue();
+    uint64_t alignment = ALIGN->getZExtValue();
+
+    // Alignment 0 is identity for alignment 1
+    if (alignment == 0)
+      alignment = 1;
 
-} MemMoveOptimizer;
+    // If the length is zero, this is a no-op
+    if (len == 0) {
+      // memset(d,c,0,a) -> noop
+      ci->eraseFromParent();
+      return true;
+    }
+
+    // If the length is larger than the alignment, we can't optimize
+    if (len > alignment)
+      return false;
+
+    // Make sure we have a constant ubyte to work with so we can extract
+    // the value to be filled.
+    ConstantInt* FILL = dyn_cast<ConstantInt>(ci->getOperand(2));
+    if (!FILL)
+      return false;
+    if (FILL->getType() != Type::UByteTy)
+      return false;
+
+    // memset(s,c,n) -> store s, c (for n=1,2,4,8)
+
+    // Extract the fill character
+    uint64_t fill_char = FILL->getZExtValue();
+    uint64_t fill_value = fill_char;
 
-/// This LibCallOptimization will simplify calls to the "pow" library 
-/// function. It looks for cases where the result of pow is well known and 
+    // Get the type we will cast to, based on size of memory area to fill, and
+    // and the value we will store there.
+    Value* dest = ci->getOperand(1);
+    Type* castType = 0;
+    switch (len) {
+      case 1:
+        castType = Type::UByteTy;
+        break;
+      case 2:
+        castType = Type::UShortTy;
+        fill_value |= fill_char << 8;
+        break;
+      case 4:
+        castType = Type::UIntTy;
+        fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
+        break;
+      case 8:
+        castType = Type::ULongTy;
+        fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
+        fill_value |= fill_char << 32 | fill_char << 40 | fill_char << 48;
+        fill_value |= fill_char << 56;
+        break;
+      default:
+        return false;
+    }
+
+    // Cast dest to the right sized primitive and then load/store
+    CastInst* DestCast = new BitCastInst(dest, PointerType::get(castType), 
+                                         dest->getName()+".cast", ci);
+    new StoreInst(ConstantInt::get(castType,fill_value),DestCast, ci);
+    ci->eraseFromParent();
+    return true;
+  }
+};
+
+LLVMMemSetOptimization MemSet32Optimizer("llvm.memset.i32");
+LLVMMemSetOptimization MemSet64Optimizer("llvm.memset.i64");
+
+
+/// This LibCallOptimization will simplify calls to the "pow" library
+/// function. It looks for cases where the result of pow is well known and
 /// substitutes the appropriate value.
 /// @brief Simplify the pow library function.
-struct PowOptimization : public LibCallOptimization
-{
+struct PowOptimization : public LibCallOptimization {
 public:
   /// @brief Default Constructor
-  PowOptimization() : LibCallOptimization("pow") {}
-  /// @brief Destructor
-  virtual ~PowOptimization() {}
+  PowOptimization() : LibCallOptimization("pow",
+      "Number of 'pow' calls simplified") {}
 
   /// @brief Make sure that the "pow" function has the right prototype
-  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
-  {
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
     // Just make sure this has 2 arguments
     return (f->arg_size() == 2);
   }
 
   /// @brief Perform the pow optimization.
-  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
-  {
+  virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
     const Type *Ty = cast<Function>(ci->getOperand(0))->getReturnType();
     Value* base = ci->getOperand(1);
     Value* expn = ci->getOperand(2);
     if (ConstantFP *Op1 = dyn_cast<ConstantFP>(base)) {
       double Op1V = Op1->getValue();
-      if (Op1V == 1.0)
-      {
+      if (Op1V == 1.0) {
         // pow(1.0,x) -> 1.0
         ci->replaceAllUsesWith(ConstantFP::get(Ty,1.0));
         ci->eraseFromParent();
         return true;
       }
-    } 
-    else if (ConstantFP* Op2 = dyn_cast<ConstantFP>(expn)) 
-    {
+    }  else if (ConstantFP* Op2 = dyn_cast<ConstantFP>(expn)) {
       double Op2V = Op2->getValue();
-      if (Op2V == 0.0)
-      {
+      if (Op2V == 0.0) {
         // pow(x,0.0) -> 1.0
         ci->replaceAllUsesWith(ConstantFP::get(Ty,1.0));
         ci->eraseFromParent();
         return true;
-      }
-      else if (Op2V == 0.5)
-      {
+      } else if (Op2V == 0.5) {
         // pow(x,0.5) -> sqrt(x)
         CallInst* sqrt_inst = new CallInst(SLC.get_sqrt(), base,
             ci->getName()+".pow",ci);
         ci->replaceAllUsesWith(sqrt_inst);
         ci->eraseFromParent();
         return true;
-      }
-      else if (Op2V == 1.0)
-      {
+      } else if (Op2V == 1.0) {
         // pow(x,1.0) -> x
         ci->replaceAllUsesWith(base);
         ci->eraseFromParent();
         return true;
-      }
-      else if (Op2V == -1.0)
-      {
+      } else if (Op2V == -1.0) {
         // pow(x,-1.0)    -> 1.0/x
-        BinaryOperator* div_inst= BinaryOperator::create(Instruction::Div,
+        BinaryOperator* div_inst= BinaryOperator::createFDiv(
           ConstantFP::get(Ty,1.0), base, ci->getName()+".pow", ci);
         ci->replaceAllUsesWith(div_inst);
         ci->eraseFromParent();
@@ -861,41 +1292,383 @@ public:
   }
 } PowOptimizer;
 
-/// This LibCallOptimization will simplify calls to the "fputs" library 
-/// function. It looks for cases where the result of fputs is not used and the
+/// This LibCallOptimization will simplify calls to the "printf" library
+/// function. It looks for cases where the result of printf is not used and the
 /// operation can be reduced to something simpler.
-/// @brief Simplify the pow library function.
-struct PutsOptimization : public LibCallOptimization
-{
+/// @brief Simplify the printf library function.
+struct PrintfOptimization : public LibCallOptimization {
 public:
   /// @brief Default Constructor
-  PutsOptimization() : LibCallOptimization("fputs") {}
+  PrintfOptimization() : LibCallOptimization("printf",
+      "Number of 'printf' calls simplified") {}
+
+  /// @brief Make sure that the "printf" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
+    // Just make sure this has at least 1 arguments
+    return (f->arg_size() >= 1);
+  }
 
-  /// @brief Destructor
-  virtual ~PutsOptimization() {}
+  /// @brief Perform the printf optimization.
+  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
+    // If the call has more than 2 operands, we can't optimize it
+    if (ci->getNumOperands() > 3 || ci->getNumOperands() <= 2)
+      return false;
+
+    // If the result of the printf call is used, none of these optimizations
+    // can be made.
+    if (!ci->use_empty())
+      return false;
+
+    // All the optimizations depend on the length of the first argument and the
+    // fact that it is a constant string array. Check that now
+    uint64_t len = 0;
+    ConstantArray* CA = 0;
+    if (!getConstantStringLength(ci->getOperand(1), len, &CA))
+      return false;
+
+    if (len != 2 && len != 3)
+      return false;
+
+    // The first character has to be a %
+    if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
+      if (CI->getZExtValue() != '%')
+        return false;
+
+    // Get the second character and switch on its value
+    ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
+    switch (CI->getZExtValue()) {
+      case 's':
+      {
+        if (len != 3 ||
+            dyn_cast<ConstantInt>(CA->getOperand(2))->getZExtValue() != '\n')
+          return false;
+
+        // printf("%s\n",str) -> puts(str)
+        Function* puts_func = SLC.get_puts();
+        if (!puts_func)
+          return false;
+        std::vector<Value*> args;
+        args.push_back(CastToCStr(ci->getOperand(2), *ci));
+        new CallInst(puts_func,args,ci->getName(),ci);
+        ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,len));
+        break;
+      }
+      case 'c':
+      {
+        // printf("%c",c) -> putchar(c)
+        if (len != 2)
+          return false;
+
+        Function* putchar_func = SLC.get_putchar();
+        if (!putchar_func)
+          return false;
+        CastInst* cast = CastInst::createSExtOrBitCast(
+            ci->getOperand(2), Type::IntTy, CI->getName()+".int", ci);
+        new CallInst(putchar_func, cast, "", ci);
+        ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy, 1));
+        break;
+      }
+      default:
+        return false;
+    }
+    ci->eraseFromParent();
+    return true;
+  }
+} PrintfOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "fprintf" library
+/// function. It looks for cases where the result of fprintf is not used and the
+/// operation can be reduced to something simpler.
+/// @brief Simplify the fprintf library function.
+struct FPrintFOptimization : public LibCallOptimization {
+public:
+  /// @brief Default Constructor
+  FPrintFOptimization() : LibCallOptimization("fprintf",
+      "Number of 'fprintf' calls simplified") {}
+
+  /// @brief Make sure that the "fprintf" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
+    // Just make sure this has at least 2 arguments
+    return (f->arg_size() >= 2);
+  }
+
+  /// @brief Perform the fprintf optimization.
+  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
+    // If the call has more than 3 operands, we can't optimize it
+    if (ci->getNumOperands() > 4 || ci->getNumOperands() <= 2)
+      return false;
+
+    // If the result of the fprintf call is used, none of these optimizations
+    // can be made.
+    if (!ci->use_empty())
+      return false;
+
+    // All the optimizations depend on the length of the second argument and the
+    // fact that it is a constant string array. Check that now
+    uint64_t len = 0;
+    ConstantArray* CA = 0;
+    if (!getConstantStringLength(ci->getOperand(2), len, &CA))
+      return false;
+
+    if (ci->getNumOperands() == 3) {
+      // Make sure there's no % in the constant array
+      for (unsigned i = 0; i < len; ++i) {
+        if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i))) {
+          // Check for the null terminator
+          if (CI->getZExtValue() == '%')
+            return false; // we found end of string
+        } else {
+          return false;
+        }
+      }
+
+      // fprintf(file,fmt) -> fwrite(fmt,strlen(fmt),file)
+      const Type* FILEptr_type = ci->getOperand(1)->getType();
+      Function* fwrite_func = SLC.get_fwrite(FILEptr_type);
+      if (!fwrite_func)
+        return false;
+
+      // Make sure that the fprintf() and fwrite() functions both take the
+      // same type of char pointer.
+      if (ci->getOperand(2)->getType() !=
+          fwrite_func->getFunctionType()->getParamType(0))
+        return false;
+
+      std::vector<Value*> args;
+      args.push_back(ci->getOperand(2));
+      args.push_back(ConstantInt::get(SLC.getIntPtrType(),len));
+      args.push_back(ConstantInt::get(SLC.getIntPtrType(),1));
+      args.push_back(ci->getOperand(1));
+      new CallInst(fwrite_func,args,ci->getName(),ci);
+      ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,len));
+      ci->eraseFromParent();
+      return true;
+    }
+
+    // The remaining optimizations require the format string to be length 2
+    // "%s" or "%c".
+    if (len != 2)
+      return false;
+
+    // The first character has to be a %
+    if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
+      if (CI->getZExtValue() != '%')
+        return false;
+
+    // Get the second character and switch on its value
+    ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
+    switch (CI->getZExtValue()) {
+      case 's':
+      {
+        uint64_t len = 0;
+        ConstantArray* CA = 0;
+        if (getConstantStringLength(ci->getOperand(3), len, &CA)) {
+          // fprintf(file,"%s",str) -> fwrite(str,strlen(str),1,file)
+          const Type* FILEptr_type = ci->getOperand(1)->getType();
+          Function* fwrite_func = SLC.get_fwrite(FILEptr_type);
+          if (!fwrite_func)
+            return false;
+          std::vector<Value*> args;
+          args.push_back(CastToCStr(ci->getOperand(3), *ci));
+          args.push_back(ConstantInt::get(SLC.getIntPtrType(),len));
+          args.push_back(ConstantInt::get(SLC.getIntPtrType(),1));
+          args.push_back(ci->getOperand(1));
+          new CallInst(fwrite_func,args,ci->getName(),ci);
+          ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,len));
+        } else {
+          // fprintf(file,"%s",str) -> fputs(str,file)
+          const Type* FILEptr_type = ci->getOperand(1)->getType();
+          Function* fputs_func = SLC.get_fputs(FILEptr_type);
+          if (!fputs_func)
+            return false;
+          std::vector<Value*> args;
+          args.push_back(CastToCStr(ci->getOperand(3), *ci));
+          args.push_back(ci->getOperand(1));
+          new CallInst(fputs_func,args,ci->getName(),ci);
+          ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,len));
+        }
+        break;
+      }
+      case 'c':
+      {
+        // fprintf(file,"%c",c) -> fputc(c,file)
+        const Type* FILEptr_type = ci->getOperand(1)->getType();
+        Function* fputc_func = SLC.get_fputc(FILEptr_type);
+        if (!fputc_func)
+          return false;
+        CastInst* cast = CastInst::createSExtOrBitCast(
+            ci->getOperand(3), Type::IntTy, CI->getName()+".int", ci);
+        new CallInst(fputc_func,cast,ci->getOperand(1),"",ci);
+        ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,1));
+        break;
+      }
+      default:
+        return false;
+    }
+    ci->eraseFromParent();
+    return true;
+  }
+} FPrintFOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "sprintf" library
+/// function. It looks for cases where the result of sprintf is not used and the
+/// operation can be reduced to something simpler.
+/// @brief Simplify the sprintf library function.
+struct SPrintFOptimization : public LibCallOptimization {
+public:
+  /// @brief Default Constructor
+  SPrintFOptimization() : LibCallOptimization("sprintf",
+      "Number of 'sprintf' calls simplified") {}
+
+  /// @brief Make sure that the "fprintf" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function *f, SimplifyLibCalls &SLC){
+    // Just make sure this has at least 2 arguments
+    return (f->getReturnType() == Type::IntTy && f->arg_size() >= 2);
+  }
+
+  /// @brief Perform the sprintf optimization.
+  virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
+    // If the call has more than 3 operands, we can't optimize it
+    if (ci->getNumOperands() > 4 || ci->getNumOperands() < 3)
+      return false;
+
+    // All the optimizations depend on the length of the second argument and the
+    // fact that it is a constant string array. Check that now
+    uint64_t len = 0;
+    ConstantArray* CA = 0;
+    if (!getConstantStringLength(ci->getOperand(2), len, &CA))
+      return false;
+
+    if (ci->getNumOperands() == 3) {
+      if (len == 0) {
+        // If the length is 0, we just need to store a null byte
+        new StoreInst(ConstantInt::get(Type::SByteTy,0),ci->getOperand(1),ci);
+        ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,0));
+        ci->eraseFromParent();
+        return true;
+      }
+
+      // Make sure there's no % in the constant array
+      for (unsigned i = 0; i < len; ++i) {
+        if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i))) {
+          // Check for the null terminator
+          if (CI->getZExtValue() == '%')
+            return false; // we found a %, can't optimize
+        } else {
+          return false; // initializer is not constant int, can't optimize
+        }
+      }
+
+      // Increment length because we want to copy the null byte too
+      len++;
+
+      // sprintf(str,fmt) -> llvm.memcpy(str,fmt,strlen(fmt),1)
+      Function* memcpy_func = SLC.get_memcpy();
+      if (!memcpy_func)
+        return false;
+      std::vector<Value*> args;
+      args.push_back(ci->getOperand(1));
+      args.push_back(ci->getOperand(2));
+      args.push_back(ConstantInt::get(SLC.getIntPtrType(),len));
+      args.push_back(ConstantInt::get(Type::UIntTy,1));
+      new CallInst(memcpy_func,args,"",ci);
+      ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,len));
+      ci->eraseFromParent();
+      return true;
+    }
+
+    // The remaining optimizations require the format string to be length 2
+    // "%s" or "%c".
+    if (len != 2)
+      return false;
+
+    // The first character has to be a %
+    if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
+      if (CI->getZExtValue() != '%')
+        return false;
+
+    // Get the second character and switch on its value
+    ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
+    switch (CI->getZExtValue()) {
+    case 's': {
+      // sprintf(dest,"%s",str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
+      Function* strlen_func = SLC.get_strlen();
+      Function* memcpy_func = SLC.get_memcpy();
+      if (!strlen_func || !memcpy_func)
+        return false;
+      
+      Value *Len = new CallInst(strlen_func, CastToCStr(ci->getOperand(3), *ci),
+                                ci->getOperand(3)->getName()+".len", ci);
+      Value *Len1 = BinaryOperator::createAdd(Len,
+                                            ConstantInt::get(Len->getType(), 1),
+                                              Len->getName()+"1", ci);
+      if (Len1->getType() != SLC.getIntPtrType())
+        Len1 = CastInst::createIntegerCast(Len1, SLC.getIntPtrType(), false,
+                                           Len1->getName(), ci);
+      std::vector<Value*> args;
+      args.push_back(CastToCStr(ci->getOperand(1), *ci));
+      args.push_back(CastToCStr(ci->getOperand(3), *ci));
+      args.push_back(Len1);
+      args.push_back(ConstantInt::get(Type::UIntTy,1));
+      new CallInst(memcpy_func, args, "", ci);
+      
+      // The strlen result is the unincremented number of bytes in the string.
+      if (!ci->use_empty()) {
+        if (Len->getType() != ci->getType())
+          Len = CastInst::createIntegerCast(Len, ci->getType(), false, 
+                                            Len->getName(), ci);
+        ci->replaceAllUsesWith(Len);
+      }
+      ci->eraseFromParent();
+      return true;
+    }
+    case 'c': {
+      // sprintf(dest,"%c",chr) -> store chr, dest
+      CastInst* cast = CastInst::createTruncOrBitCast(
+          ci->getOperand(3), Type::SByteTy, "char", ci);
+      new StoreInst(cast, ci->getOperand(1), ci);
+      GetElementPtrInst* gep = new GetElementPtrInst(ci->getOperand(1),
+        ConstantInt::get(Type::UIntTy,1),ci->getOperand(1)->getName()+".end",
+        ci);
+      new StoreInst(ConstantInt::get(Type::SByteTy,0),gep,ci);
+      ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,1));
+      ci->eraseFromParent();
+      return true;
+    }
+    }
+    return false;
+  }
+} SPrintFOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "fputs" library
+/// function. It looks for cases where the result of fputs is not used and the
+/// operation can be reduced to something simpler.
+/// @brief Simplify the puts library function.
+struct PutsOptimization : public LibCallOptimization {
+public:
+  /// @brief Default Constructor
+  PutsOptimization() : LibCallOptimization("fputs",
+      "Number of 'fputs' calls simplified") {}
 
   /// @brief Make sure that the "fputs" function has the right prototype
-  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
-  {
+  virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
     // Just make sure this has 2 arguments
-    return (f->arg_size() == 2);
+    return F->arg_size() == 2;
   }
 
   /// @brief Perform the fputs optimization.
-  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
-  {
+  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
     // If the result is used, none of these optimizations work
-    if (!ci->hasNUses(0)) 
+    if (!ci->use_empty())
       return false;
 
     // All the optimizations depend on the length of the first argument and the
     // fact that it is a constant string array. Check that now
-    uint64_t len = 0; 
+    uint64_t len = 0;
     if (!getConstantStringLength(ci->getOperand(1), len))
       return false;
 
-    switch (len)
-    {
+    switch (len) {
       case 0:
         // fputs("",F) -> noop
         break;
@@ -908,13 +1681,13 @@ public:
           return false;
         LoadInst* loadi = new LoadInst(ci->getOperand(1),
           ci->getOperand(1)->getName()+".byte",ci);
-        CastInst* casti = new CastInst(loadi,Type::IntTy,
-          loadi->getName()+".int",ci);
+        CastInst* casti = new SExtInst(loadi, Type::IntTy, 
+                                       loadi->getName()+".int", ci);
         new CallInst(fputc_func,casti,ci->getOperand(2),"",ci);
         break;
       }
       default:
-      {  
+      {
         // fputs(s,F)  -> fwrite(s,1,len,F) (if s is constant and strlen(s) > 1)
         const Type* FILEptr_type = ci->getOperand(2)->getType();
         Function* fwrite_func = SLC.get_fwrite(FILEptr_type);
@@ -922,8 +1695,8 @@ public:
           return false;
         std::vector<Value*> parms;
         parms.push_back(ci->getOperand(1));
-        parms.push_back(ConstantUInt::get(SLC.getIntPtrType(),len));
-        parms.push_back(ConstantUInt::get(SLC.getIntPtrType(),1));
+        parms.push_back(ConstantInt::get(SLC.getIntPtrType(),len));
+        parms.push_back(ConstantInt::get(SLC.getIntPtrType(),1));
         parms.push_back(ci->getOperand(2));
         new CallInst(fwrite_func,parms,"",ci);
         break;
@@ -934,32 +1707,97 @@ public:
   }
 } PutsOptimizer;
 
-/// This LibCallOptimization will simplify calls to the "toascii" library 
+/// This LibCallOptimization will simplify calls to the "isdigit" library
+/// function. It simply does range checks the parameter explicitly.
+/// @brief Simplify the isdigit library function.
+struct isdigitOptimization : public LibCallOptimization {
+public:
+  isdigitOptimization() : LibCallOptimization("isdigit",
+      "Number of 'isdigit' calls simplified") {}
+
+  /// @brief Make sure that the "isdigit" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
+    // Just make sure this has 1 argument
+    return (f->arg_size() == 1);
+  }
+
+  /// @brief Perform the toascii optimization.
+  virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
+    if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1))) {
+      // isdigit(c)   -> 0 or 1, if 'c' is constant
+      uint64_t val = CI->getZExtValue();
+      if (val >= '0' && val <='9')
+        ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,1));
+      else
+        ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,0));
+      ci->eraseFromParent();
+      return true;
+    }
+
+    // isdigit(c)   -> (unsigned)c - '0' <= 9
+    CastInst* cast = CastInst::createIntegerCast(ci->getOperand(1),
+        Type::UIntTy, false/*ZExt*/, ci->getOperand(1)->getName()+".uint", ci);
+    BinaryOperator* sub_inst = BinaryOperator::createSub(cast,
+        ConstantInt::get(Type::UIntTy,0x30),
+        ci->getOperand(1)->getName()+".sub",ci);
+    ICmpInst* setcond_inst = new ICmpInst(ICmpInst::ICMP_ULE,sub_inst,
+        ConstantInt::get(Type::UIntTy,9),
+        ci->getOperand(1)->getName()+".cmp",ci);
+    CastInst* c2 = new ZExtInst(setcond_inst, Type::IntTy, 
+        ci->getOperand(1)->getName()+".isdigit", ci);
+    ci->replaceAllUsesWith(c2);
+    ci->eraseFromParent();
+    return true;
+  }
+} isdigitOptimizer;
+
+struct isasciiOptimization : public LibCallOptimization {
+public:
+  isasciiOptimization()
+    : LibCallOptimization("isascii", "Number of 'isascii' calls simplified") {}
+  
+  virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+    return F->arg_size() == 1 && F->arg_begin()->getType()->isInteger() && 
+           F->getReturnType()->isInteger();
+  }
+  
+  /// @brief Perform the isascii optimization.
+  virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+    // isascii(c)   -> (unsigned)c < 128
+    Value *V = CI->getOperand(1);
+    Value *Cmp = new ICmpInst(ICmpInst::ICMP_ULT, V, 
+                              ConstantInt::get(V->getType(), 128), 
+                              V->getName()+".isascii", CI);
+    if (Cmp->getType() != CI->getType())
+      Cmp = new BitCastInst(Cmp, CI->getType(), Cmp->getName(), CI);
+    CI->replaceAllUsesWith(Cmp);
+    CI->eraseFromParent();
+    return true;
+  }
+} isasciiOptimizer;
+
+
+/// This LibCallOptimization will simplify calls to the "toascii" library
 /// function. It simply does the corresponding and operation to restrict the
 /// range of values to the ASCII character set (0-127).
 /// @brief Simplify the toascii library function.
-struct ToAsciiOptimization : public LibCallOptimization
-{
+struct ToAsciiOptimization : public LibCallOptimization {
 public:
   /// @brief Default Constructor
-  ToAsciiOptimization() : LibCallOptimization("toascii") {}
-
-  /// @brief Destructor
-  virtual ~ToAsciiOptimization() {}
+  ToAsciiOptimization() : LibCallOptimization("toascii",
+      "Number of 'toascii' calls simplified") {}
 
   /// @brief Make sure that the "fputs" function has the right prototype
-  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
-  {
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
     // Just make sure this has 2 arguments
     return (f->arg_size() == 1);
   }
 
   /// @brief Perform the toascii optimization.
-  virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
-  {
+  virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
     // toascii(c)   -> (c & 0x7f)
     Value* chr = ci->getOperand(1);
-    BinaryOperator* and_inst = BinaryOperator::create(Instruction::And,chr,
+    BinaryOperator* and_inst = BinaryOperator::createAnd(chr,
         ConstantInt::get(chr->getType(),0x7F),ci->getName()+".toascii",ci);
     ci->replaceAllUsesWith(and_inst);
     ci->eraseFromParent();
@@ -967,23 +1805,227 @@ public:
   }
 } ToAsciiOptimizer;
 
+/// This LibCallOptimization will simplify calls to the "ffs" library
+/// calls which find the first set bit in an int, long, or long long. The
+/// optimization is to compute the result at compile time if the argument is
+/// a constant.
+/// @brief Simplify the ffs library function.
+struct FFSOptimization : public LibCallOptimization {
+protected:
+  /// @brief Subclass Constructor
+  FFSOptimization(const char* funcName, const char* description)
+    : LibCallOptimization(funcName, description) {}
+
+public:
+  /// @brief Default Constructor
+  FFSOptimization() : LibCallOptimization("ffs",
+      "Number of 'ffs' calls simplified") {}
+
+  /// @brief Make sure that the "ffs" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+    // Just make sure this has 2 arguments
+    return F->arg_size() == 1 && F->getReturnType() == Type::IntTy;
+  }
+
+  /// @brief Perform the ffs optimization.
+  virtual bool OptimizeCall(CallInst *TheCall, SimplifyLibCalls &SLC) {
+    if (ConstantInt *CI = dyn_cast<ConstantInt>(TheCall->getOperand(1))) {
+      // ffs(cnst)  -> bit#
+      // ffsl(cnst) -> bit#
+      // ffsll(cnst) -> bit#
+      uint64_t val = CI->getZExtValue();
+      int result = 0;
+      if (val) {
+        ++result;
+        while ((val & 1) == 0) {
+          ++result;
+          val >>= 1;
+        }
+      }
+      TheCall->replaceAllUsesWith(ConstantInt::get(Type::IntTy, result));
+      TheCall->eraseFromParent();
+      return true;
+    }
+
+    // ffs(x)   -> x == 0 ? 0 : llvm.cttz(x)+1
+    // ffsl(x)  -> x == 0 ? 0 : llvm.cttz(x)+1
+    // ffsll(x) -> x == 0 ? 0 : llvm.cttz(x)+1
+    const Type *ArgType = TheCall->getOperand(1)->getType();
+    ArgType = ArgType->getUnsignedVersion();
+    const char *CTTZName;
+    switch (ArgType->getTypeID()) {
+    default: assert(0 && "Unknown unsigned type!");
+    case Type::UByteTyID : CTTZName = "llvm.cttz.i8" ; break;
+    case Type::UShortTyID: CTTZName = "llvm.cttz.i16"; break;
+    case Type::UIntTyID  : CTTZName = "llvm.cttz.i32"; break;
+    case Type::ULongTyID : CTTZName = "llvm.cttz.i64"; break;
+    }
+    
+    Function *F = SLC.getModule()->getOrInsertFunction(CTTZName, ArgType,
+                                                       ArgType, NULL);
+    Value *V = CastInst::createIntegerCast(TheCall->getOperand(1), ArgType, 
+                                           false/*ZExt*/, "tmp", TheCall);
+    Value *V2 = new CallInst(F, V, "tmp", TheCall);
+    V2 = CastInst::createIntegerCast(V2, Type::IntTy, false/*ZExt*/, 
+                                     "tmp", TheCall);
+    V2 = BinaryOperator::createAdd(V2, ConstantInt::get(Type::IntTy, 1),
+                                   "tmp", TheCall);
+    Value *Cond = new ICmpInst(ICmpInst::ICMP_EQ, V, 
+                               Constant::getNullValue(V->getType()), "tmp", 
+                               TheCall);
+    V2 = new SelectInst(Cond, ConstantInt::get(Type::IntTy, 0), V2,
+                        TheCall->getName(), TheCall);
+    TheCall->replaceAllUsesWith(V2);
+    TheCall->eraseFromParent();
+    return true;
+  }
+} FFSOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "ffsl" library
+/// calls. It simply uses FFSOptimization for which the transformation is
+/// identical.
+/// @brief Simplify the ffsl library function.
+struct FFSLOptimization : public FFSOptimization {
+public:
+  /// @brief Default Constructor
+  FFSLOptimization() : FFSOptimization("ffsl",
+      "Number of 'ffsl' calls simplified") {}
+
+} FFSLOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "ffsll" library
+/// calls. It simply uses FFSOptimization for which the transformation is
+/// identical.
+/// @brief Simplify the ffsl library function.
+struct FFSLLOptimization : public FFSOptimization {
+public:
+  /// @brief Default Constructor
+  FFSLLOptimization() : FFSOptimization("ffsll",
+      "Number of 'ffsll' calls simplified") {}
+
+} FFSLLOptimizer;
+
+/// This optimizes unary functions that take and return doubles.
+struct UnaryDoubleFPOptimizer : public LibCallOptimization {
+  UnaryDoubleFPOptimizer(const char *Fn, const char *Desc)
+  : LibCallOptimization(Fn, Desc) {}
+  
+  // Make sure that this function has the right prototype
+  virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+    return F->arg_size() == 1 && F->arg_begin()->getType() == Type::DoubleTy &&
+           F->getReturnType() == Type::DoubleTy;
+  }
+
+  /// ShrinkFunctionToFloatVersion - If the input to this function is really a
+  /// float, strength reduce this to a float version of the function,
+  /// e.g. floor((double)FLT) -> (double)floorf(FLT).  This can only be called
+  /// when the target supports the destination function and where there can be
+  /// no precision loss.
+  static bool ShrinkFunctionToFloatVersion(CallInst *CI, SimplifyLibCalls &SLC,
+                                           Function *(SimplifyLibCalls::*FP)()){
+    if (CastInst *Cast = dyn_cast<CastInst>(CI->getOperand(1)))
+      if (Cast->getOperand(0)->getType() == Type::FloatTy) {
+        Value *New = new CallInst((SLC.*FP)(), Cast->getOperand(0),
+                                  CI->getName(), CI);
+        New = new FPExtInst(New, Type::DoubleTy, CI->getName(), CI);
+        CI->replaceAllUsesWith(New);
+        CI->eraseFromParent();
+        if (Cast->use_empty())
+          Cast->eraseFromParent();
+        return true;
+      }
+    return false;
+  }
+};
+
+
+struct FloorOptimization : public UnaryDoubleFPOptimizer {
+  FloorOptimization()
+    : UnaryDoubleFPOptimizer("floor", "Number of 'floor' calls simplified") {}
+  
+  virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+#ifdef HAVE_FLOORF
+    // If this is a float argument passed in, convert to floorf.
+    if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_floorf))
+      return true;
+#endif
+    return false; // opt failed
+  }
+} FloorOptimizer;
+
+struct CeilOptimization : public UnaryDoubleFPOptimizer {
+  CeilOptimization()
+  : UnaryDoubleFPOptimizer("ceil", "Number of 'ceil' calls simplified") {}
+  
+  virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+#ifdef HAVE_CEILF
+    // If this is a float argument passed in, convert to ceilf.
+    if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_ceilf))
+      return true;
+#endif
+    return false; // opt failed
+  }
+} CeilOptimizer;
+
+struct RoundOptimization : public UnaryDoubleFPOptimizer {
+  RoundOptimization()
+  : UnaryDoubleFPOptimizer("round", "Number of 'round' calls simplified") {}
+  
+  virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+#ifdef HAVE_ROUNDF
+    // If this is a float argument passed in, convert to roundf.
+    if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_roundf))
+      return true;
+#endif
+    return false; // opt failed
+  }
+} RoundOptimizer;
+
+struct RintOptimization : public UnaryDoubleFPOptimizer {
+  RintOptimization()
+  : UnaryDoubleFPOptimizer("rint", "Number of 'rint' calls simplified") {}
+  
+  virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+#ifdef HAVE_RINTF
+    // If this is a float argument passed in, convert to rintf.
+    if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_rintf))
+      return true;
+#endif
+    return false; // opt failed
+  }
+} RintOptimizer;
+
+struct NearByIntOptimization : public UnaryDoubleFPOptimizer {
+  NearByIntOptimization()
+  : UnaryDoubleFPOptimizer("nearbyint",
+                           "Number of 'nearbyint' calls simplified") {}
+  
+  virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+#ifdef HAVE_NEARBYINTF
+    // If this is a float argument passed in, convert to nearbyintf.
+    if (ShrinkFunctionToFloatVersion(CI, SLC,&SimplifyLibCalls::get_nearbyintf))
+      return true;
+#endif
+    return false; // opt failed
+  }
+} NearByIntOptimizer;
+
 /// A function to compute the length of a null-terminated constant array of
-/// integers.  This function can't rely on the size of the constant array 
-/// because there could be a null terminator in the middle of the array. 
-/// We also have to bail out if we find a non-integer constant initializer 
-/// of one of the elements or if there is no null-terminator. The logic 
+/// integers.  This function can't rely on the size of the constant array
+/// because there could be a null terminator in the middle of the array.
+/// We also have to bail out if we find a non-integer constant initializer
+/// of one of the elements or if there is no null-terminator. The logic
 /// below checks each of these conditions and will return true only if all
 /// conditions are met. In that case, the \p len parameter is set to the length
 /// of the null-terminated string. If false is returned, the conditions were
 /// not met and len is set to 0.
 /// @brief Get the length of a constant string (null-terminated array).
-bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
-{
+bool getConstantStringLength(Value *V, uint64_t &len, ConstantArray **CA) {
   assert(V != 0 && "Invalid args to getConstantStringLength");
-  len = 0; // make sure we initialize this 
+  len = 0; // make sure we initialize this
   User* GEP = 0;
-  // If the value is not a GEP instruction nor a constant expression with a 
-  // GEP instruction, then return false because ConstantArray can't occur 
+  // If the value is not a GEP instruction nor a constant expression with a
+  // GEP instruction, then return false because ConstantArray can't occur
   // any other way
   if (GetElementPtrInst* GEPI = dyn_cast<GetElementPtrInst>(V))
     GEP = GEPI;
@@ -1000,22 +2042,20 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
     return false;
 
   // Check to make sure that the first operand of the GEP is an integer and
-  // has value 0 so that we are sure we're indexing into the initializer. 
-  if (ConstantInt* op1 = dyn_cast<ConstantInt>(GEP->getOperand(1)))
-  {
+  // has value 0 so that we are sure we're indexing into the initializer.
+  if (ConstantInt* op1 = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
     if (!op1->isNullValue())
       return false;
-  }
-  else
+  } else
     return false;
 
   // Ensure that the second operand is a ConstantInt. If it isn't then this
-  // GEP is wonky and we're not really sure what were referencing into and 
+  // GEP is wonky and we're not really sure what were referencing into and
   // better of not optimizing it. While we're at it, get the second index
   // value. We'll need this later for indexing the ConstantArray.
   uint64_t start_idx = 0;
   if (ConstantInt* CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
-    start_idx = CI->getRawValue();
+    start_idx = CI->getZExtValue();
   else
     return false;
 
@@ -1030,8 +2070,7 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
   Constant* INTLZR = GV->getInitializer();
 
   // Handle the ConstantAggregateZero case
-  if (ConstantAggregateZero* CAZ = dyn_cast<ConstantAggregateZero>(INTLZR))
-  {
+  if (isa<ConstantAggregateZero>(INTLZR)) {
     // This is a degenerate case. The initializer is constant zero so the
     // length of the string must be zero.
     len = 0;
@@ -1047,18 +2086,16 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
   uint64_t max_elems = A->getType()->getNumElements();
 
   // Traverse the constant array from start_idx (derived above) which is
-  // the place the GEP refers to in the array. 
-  for ( len = start_idx; len < max_elems; len++)
-  {
-    if (ConstantInt* CI = dyn_cast<ConstantInt>(A->getOperand(len)))
-    {
+  // the place the GEP refers to in the array.
+  for (len = start_idx; len < max_elems; len++) {
+    if (ConstantInt *CI = dyn_cast<ConstantInt>(A->getOperand(len))) {
       // Check for the null terminator
       if (CI->isNullValue())
         break; // we found end of string
-    }
-    else
+    } else
       return false; // This array isn't suitable, non-int initializer
   }
+  
   if (len >= max_elems)
     return false; // This array isn't null terminated
 
@@ -1069,7 +2106,19 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
   return true; // success!
 }
 
-// TODO: 
+/// CastToCStr - Return V if it is an sbyte*, otherwise cast it to sbyte*,
+/// inserting the cast before IP, and return the cast.
+/// @brief Cast a value to a "C" string.
+Value *CastToCStr(Value *V, Instruction &IP) {
+  assert(isa<PointerType>(V->getType()) && 
+         "Can't cast non-pointer type to C string type");
+  const Type *SBPTy = PointerType::get(Type::SByteTy);
+  if (V->getType() != SBPTy)
+    return new BitCastInst(V, SBPTy, V->getName(), &IP);
+  return V;
+}
+
+// TODO:
 //   Additional cases that we need to add to this file:
 //
 // cbrt:
@@ -1083,22 +2132,6 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
 // exp, expf, expl:
 //   * exp(log(x))  -> x
 //
-// ffs, ffsl, ffsll:
-//   * ffs(cnst)     -> cnst'
-//
-// fprintf:
-//   * fprintf(file,fmt) -> fputs(fmt,file) 
-//       (if fmt is constant and constains no % characters)
-//   * fprintf(file,"%s",str) -> fputs(orig,str)
-//       (only if the fprintf result is not used)
-//   * fprintf(file,"%c",chr) -> fputc(chr,file)
-//
-// isascii:
-//   * isascii(c)    -> ((c & ~0x7f) == 0)
-//   
-// isdigit:
-//   * isdigit(c)    -> (unsigned)(c) - '0' <= 9
-//
 // log, logf, logl:
 //   * log(exp(x))   -> x
 //   * log(x**y)     -> y*log(x)
@@ -1112,21 +2145,13 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
 //   * lround(cnst) -> cnst'
 //
 // memcmp:
-//   * memcmp(s1,s2,0) -> 0
-//   * memcmp(x,x,l)   -> 0
 //   * memcmp(x,y,l)   -> cnst
 //      (if all arguments are constant and strlen(x) <= l and strlen(y) <= l)
-//   * memcpy(x,y,1)   -> *x - *y
 //
 // memmove:
-//   * memmove(d,s,l,a) -> memcpy(d,s,l,a) 
+//   * memmove(d,s,l,a) -> memcpy(d,s,l,a)
 //       (if s is a global constant array)
 //
-// memset:
-//   * memset(s,c,0) -> noop
-//   * memset(s,c,n) -> store s, c
-//      (for n=1,2,4,8)
-//
 // pow, powf, powl:
 //   * pow(exp(x),y)  -> exp(x*y)
 //   * pow(sqrt(x),y) -> pow(x,y*0.5)
@@ -1142,42 +2167,24 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
 //   * signbit(cnst) -> cnst'
 //   * signbit(nncst) -> 0 (if pstv is a non-negative constant)
 //
-// sprintf:
-//   * sprintf(dest,fmt) -> strcpy(dest,fmt) 
-//       (if fmt is constant and constains no % characters)
-//   * sprintf(dest,"%s",orig) -> strcpy(dest,orig)
-//       (only if the sprintf result is not used)
-//
 // sqrt, sqrtf, sqrtl:
 //   * sqrt(expN(x))  -> expN(x*0.5)
 //   * sqrt(Nroot(x)) -> pow(x,1/(2*N))
 //   * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
 //
-// strchr, strrchr:
-//   * strchr(s,c)  -> offset_of_in(c,s)
-//      (if c is a constant integer and s is a constant string)
+// stpcpy:
+//   * stpcpy(str, "literal") ->
+//           llvm.memcpy(str,"literal",strlen("literal")+1,1)
+// strrchr:
 //   * strrchr(s,c) -> reverse_offset_of_in(c,s)
 //      (if c is a constant integer and s is a constant string)
 //   * strrchr(s1,0) -> strchr(s1,0)
 //
-// strcmp:
-//   * strcmp(x,x)  -> 0
-//   * strcmp(x,"") -> *x
-//   * strcmp("",x) -> *x
-//   * strcmp(x,y)  -> cnst  (if both x and y are constant strings)
-//
 // strncat:
 //   * strncat(x,y,0) -> x
 //   * strncat(x,y,0) -> x (if strlen(y) = 0)
 //   * strncat(x,y,l) -> strcat(x,y) (if y and l are constants an l > strlen(y))
 //
-// strncmp:
-//   * strncmp(x,y,0)   -> 0
-//   * strncmp(x,x,l)   -> 0
-//   * strncmp(x,"",l)  -> *x
-//   * strncmp("",x,l)  -> *x
-//   * strncmp(x,y,1)   -> *x - *y
-//
 // strncpy:
 //   * strncpy(d,s,0) -> d
 //   * strncpy(d,s,l) -> memcpy(d,s,l,1)
@@ -1199,14 +2206,14 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
 //
 // strstr:
 //   * strstr(x,x)  -> x
-//   * strstr(s1,s2) -> offset_of_s2_in(s1)  
+//   * strstr(s1,s2) -> offset_of_s2_in(s1)
 //       (if s1 and s2 are constant strings)
-//    
+//
 // tan, tanf, tanl:
 //   * tan(atan(x)) -> x
-// 
+//
 // trunc, truncf, truncl:
 //   * trunc(cnst) -> cnst'
 //
-// 
+//
 }