X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FIPO%2FSimplifyLibCalls.cpp;h=63ab333430c8ed5df59c238ff32e7e1381523561;hb=66c5fd6c537269eaef0f630fa14360dcaff6a295;hp=4c1fe29c2a3e9bfe229c7b08032aa93339652aca;hpb=58b563ce4351996dd403646231fed40794a0aa4c;p=oota-llvm.git

diff --git a/lib/Transforms/IPO/SimplifyLibCalls.cpp b/lib/Transforms/IPO/SimplifyLibCalls.cpp
index 4c1fe29c2a3..63ab333430c 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.
 //
 //===----------------------------------------------------------------------===//
 
@@ -34,42 +35,45 @@ 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");
+Statistic<> SimplifiedLibCalls("simplify-libcalls",
+  "Number of library calls simplified");
 
 // Forward declarations
 class LibCallOptimization;
 class SimplifyLibCalls;
 
+/// This hash map 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 hash_map<std::string,LibCallOptimization*> optlist;
 
 /// 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
 {
 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, 
-                      const char* stat_name, const char* description )
+  LibCallOptimization(const char* fname, const char* description )
     : func_name(fname)
 #ifndef NDEBUG
-    , occurrences(stat_name,description)
+    , occurrences("simplify-libcalls",description)
 #endif
   {
     // Register this call optimizer in the optlist (a hash_map)
@@ -80,12 +84,12 @@ public:
   virtual ~LibCallOptimization() { optlist.erase(func_name); }
 
   /// 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
@@ -94,10 +98,10 @@ 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.
@@ -111,7 +115,7 @@ public:
 
 #ifndef NDEBUG
   /// @brief Called by SimplifyLibCalls to update the occurrences statistic.
-  void succeeded() { ++occurrences; }
+  void succeeded() { DEBUG(++occurrences); }
 #endif
 
 private:
@@ -121,15 +125,16 @@ private:
 #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
@@ -153,8 +158,8 @@ public:
 
     // 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
@@ -163,8 +168,8 @@ public:
       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 
+        // 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())
           continue;
@@ -179,7 +184,7 @@ public:
           continue;
 
         // Loop over each of the uses of the function
-        for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end(); 
+        for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end();
              UI != UE ; )
         {
           // If the use of the function is a call instruction
@@ -218,7 +223,7 @@ public:
       std::vector<const Type*> args;
       args.push_back(Type::IntTy);
       args.push_back(FILEptr_type);
-      FunctionType* fputc_type = 
+      FunctionType* fputc_type =
         FunctionType::get(Type::IntTy, args, false);
       fputc_func = M->getOrInsertFunction("fputc",fputc_type);
     }
@@ -235,7 +240,7 @@ public:
       args.push_back(TD->getIntPtrType());
       args.push_back(TD->getIntPtrType());
       args.push_back(FILEptr_type);
-      FunctionType* fwrite_type = 
+      FunctionType* fwrite_type =
         FunctionType::get(TD->getIntPtrType(), args, false);
       fwrite_func = M->getOrInsertFunction("fwrite",fwrite_type);
     }
@@ -249,7 +254,7 @@ public:
     {
       std::vector<const Type*> args;
       args.push_back(Type::DoubleTy);
-      FunctionType* sqrt_type = 
+      FunctionType* sqrt_type =
         FunctionType::get(Type::DoubleTy, args, false);
       sqrt_func = M->getOrInsertFunction("sqrt",sqrt_type);
     }
@@ -264,7 +269,7 @@ public:
       std::vector<const Type*> args;
       args.push_back(PointerType::get(Type::SByteTy));
       args.push_back(PointerType::get(Type::SByteTy));
-      FunctionType* strcpy_type = 
+      FunctionType* strcpy_type =
         FunctionType::get(PointerType::get(Type::SByteTy), args, false);
       strcpy_func = M->getOrInsertFunction("strcpy",strcpy_type);
     }
@@ -278,7 +283,7 @@ public:
     {
       std::vector<const Type*> args;
       args.push_back(PointerType::get(Type::SByteTy));
-      FunctionType* strlen_type = 
+      FunctionType* strlen_type =
         FunctionType::get(TD->getIntPtrType(), args, false);
       strlen_func = M->getOrInsertFunction("strlen",strlen_type);
     }
@@ -302,22 +307,23 @@ public:
   }
 
   /// @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::UIntTy);
-      args.push_back(Type::UIntTy);
-      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);
+      memcpy_func = M->getOrInsertFunction("llvm.memcpy", Type::VoidTy,SBP, SBP,
+                                           Type::UIntTy, Type::UIntTy,
+                                           (Type *)0);
     }
     return memcpy_func;
   }
 
+  Function* get_floorf() {
+    if (!floorf_func)
+      floorf_func = M->getOrInsertFunction("floorf", Type::FloatTy,
+                                           Type::FloatTy, (Type *)0);
+    return floorf_func;
+  }
+  
 private:
   /// @brief Reset our cached data for a new Module
   void reset(Module& mod)
@@ -331,6 +337,7 @@ private:
     sqrt_func   = 0;
     strcpy_func = 0;
     strlen_func = 0;
+    floorf_func = 0;
   }
 
 private:
@@ -341,30 +348,32 @@ private:
   Function* sqrt_func;   ///< Cached sqrt function
   Function* strcpy_func; ///< Cached strcpy function
   Function* strlen_func; ///< Cached strlen function
+  Function* floorf_func; ///< Cached floorf function
   Module* M;             ///< Cached Module
   TargetData* TD;        ///< Cached TargetData
 };
 
 // Register the pass
-RegisterOpt<SimplifyLibCalls> 
+RegisterOpt<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
@@ -374,11 +383,10 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** A = 0 );
 struct ExitInMainOptimization : public LibCallOptimization
 {
   ExitInMainOptimization() : LibCallOptimization("exit",
-      "simplify-libcalls:exit","Number of 'exit' calls simplified") {}
-  virtual ~ExitInMainOptimization() {}
+      "Number of 'exit' calls simplified") {}
 
   // Make sure the called function looks like exit (int argument, int return
-  // type, external linkage, not varargs). 
+  // type, external linkage, not varargs).
   virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
   {
     if (f->arg_size() >= 1)
@@ -391,18 +399,18 @@ struct ExitInMainOptimization : public LibCallOptimization
   {
     // 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 
+          // 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);
 
@@ -428,10 +436,10 @@ 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.
@@ -440,17 +448,15 @@ struct StrCatOptimization : public LibCallOptimization
 public:
   /// @brief Default constructor
   StrCatOptimization() : LibCallOptimization("strcat",
-      "simplify-libcalls:strcat","Number of 'strcat' calls simplified") {}
+      "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))
@@ -471,7 +477,7 @@ public:
     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;
@@ -490,19 +496,19 @@ 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
@@ -514,8 +520,8 @@ public:
     vals.push_back(ConstantUInt::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();
@@ -523,7 +529,7 @@ public:
   }
 } StrCatOptimizer;
 
-/// This LibCallOptimization will simplify a call to the strchr library 
+/// 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.
@@ -531,19 +537,18 @@ struct StrChrOptimization : public LibCallOptimization
 {
 public:
   StrChrOptimization() : LibCallOptimization("strchr",
-      "simplify-libcalls:strchr","Number of 'strchr' calls simplified") {}
-  virtual ~StrChrOptimization() {}
+      "Number of 'strchr' calls simplified") {}
 
   /// @brief Make sure that the "strchr" 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->getReturnType() == PointerType::get(Type::SByteTy) &&
         f->arg_size() == 2)
       return true;
     return false;
   }
 
-  /// @brief Perform the strcpy optimization
+  /// @brief Perform the strchr optimizations
   virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
   {
     // If there aren't three operands, bail
@@ -615,7 +620,7 @@ public:
   }
 } StrChrOptimizer;
 
-/// This LibCallOptimization will simplify a call to the strcmp library 
+/// 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.
@@ -623,23 +628,22 @@ struct StrCmpOptimization : public LibCallOptimization
 {
 public:
   StrCmpOptimization() : LibCallOptimization("strcmp",
-      "simplify-libcalls:strcmp","Number of 'strcmp' calls simplified") {}
-  virtual ~StrCmpOptimization() {}
+      "Number of 'strcmp' calls simplified") {}
 
-  /// @brief Make sure that the "strcpy" function has the right prototype
-  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC) 
+  /// @brief Make sure that the "strcmp" function has the right prototype
+  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
   {
     if (f->getReturnType() == Type::IntTy && f->arg_size() == 2)
       return true;
     return false;
   }
 
-  /// @brief Perform the strcpy optimization
+  /// @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 a constant 0
-    // because the call is a no-op. 
+    // because the call is a no-op.
     Value* s1 = ci->getOperand(1);
     Value* s2 = ci->getOperand(2);
     if (s1 == s2)
@@ -659,8 +663,9 @@ public:
       if (len_1 == 0)
       {
         // strcmp("",x) -> *x
-        LoadInst* load = new LoadInst(s1,ci->getName()+".load",ci);
-        CastInst* cast = 
+        LoadInst* load =
+          new LoadInst(CastToCStr(s2,*ci), ci->getName()+".load",ci);
+        CastInst* cast =
           new CastInst(load,Type::IntTy,ci->getName()+".int",ci);
         ci->replaceAllUsesWith(cast);
         ci->eraseFromParent();
@@ -677,8 +682,9 @@ public:
       if (len_2 == 0)
       {
         // strcmp(x,"") -> *x
-        LoadInst* load = new LoadInst(s2,ci->getName()+".val",ci);
-        CastInst* cast = 
+        LoadInst* load =
+          new LoadInst(CastToCStr(s1,*ci),ci->getName()+".val",ci);
+        CastInst* cast =
           new CastInst(load,Type::IntTy,ci->getName()+".int",ci);
         ci->replaceAllUsesWith(cast);
         ci->eraseFromParent();
@@ -700,7 +706,7 @@ public:
   }
 } StrCmpOptimizer;
 
-/// This LibCallOptimization will simplify a call to the strncmp library 
+/// 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.
@@ -708,11 +714,10 @@ struct StrNCmpOptimization : public LibCallOptimization
 {
 public:
   StrNCmpOptimization() : LibCallOptimization("strncmp",
-      "simplify-libcalls:strncmp","Number of 'strncmp' calls simplified") {}
-  virtual ~StrNCmpOptimization() {}
+      "Number of 'strncmp' calls simplified") {}
 
-  /// @brief Make sure that the "strcpy" function has the right prototype
-  virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC) 
+  /// @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;
@@ -724,7 +729,7 @@ public:
   {
     // 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. 
+    // because the call is a no-op.
     Value* s1 = ci->getOperand(1);
     Value* s2 = ci->getOperand(2);
     if (s1 == s2)
@@ -749,7 +754,7 @@ public:
         ci->replaceAllUsesWith(ConstantInt::get(Type::IntTy,0));
         ci->eraseFromParent();
         return true;
-      } 
+      }
     }
 
     bool isstr_1 = false;
@@ -762,7 +767,7 @@ public:
       {
         // strncmp("",x) -> *x
         LoadInst* load = new LoadInst(s1,ci->getName()+".load",ci);
-        CastInst* cast = 
+        CastInst* cast =
           new CastInst(load,Type::IntTy,ci->getName()+".int",ci);
         ci->replaceAllUsesWith(cast);
         ci->eraseFromParent();
@@ -780,7 +785,7 @@ public:
       {
         // strncmp(x,"") -> *x
         LoadInst* load = new LoadInst(s2,ci->getName()+".val",ci);
-        CastInst* cast = 
+        CastInst* cast =
           new CastInst(load,Type::IntTy,ci->getName()+".int",ci);
         ci->replaceAllUsesWith(cast);
         ci->eraseFromParent();
@@ -802,8 +807,8 @@ public:
   }
 } StrNCmpOptimizer;
 
-/// This LibCallOptimization will simplify a call to the strcpy library 
-/// function.  Two optimizations are possible: 
+/// 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.
@@ -811,14 +816,13 @@ struct StrCpyOptimization : public LibCallOptimization
 {
 public:
   StrCpyOptimization() : LibCallOptimization("strcpy",
-      "simplify-libcalls:strcpy","Number of 'strcpy' calls simplified") {}
-  virtual ~StrCpyOptimization() {}
+      "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))
@@ -836,7 +840,7 @@ public:
   {
     // 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.
@@ -848,7 +852,7 @@ public:
       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
@@ -883,8 +887,8 @@ public:
     vals.push_back(ConstantUInt::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();
@@ -892,21 +896,20 @@ 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",
-      "simplify-libcalls:strlen","Number of 'strlen' calls simplified") {}
-  virtual ~StrLenOptimization() {}
+      "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;
@@ -916,20 +919,179 @@ 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 binary operator?
+      if (BinaryOperator* bop = dyn_cast<BinaryOperator>(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->getRawValue();
+
+          // If its compared against length 0 with == or !=
+          if (val == 0 &&
+              (bop->getOpcode() == Instruction::SetEQ ||
+               bop->getOpcode() == Instruction::SetNE))
+          {
+            // strlen(x) != 0 -> *x != 0
+            // strlen(x) == 0 -> *x == 0
+            LoadInst* load = new LoadInst(str,str->getName()+".first",ci);
+            BinaryOperator* rbop = BinaryOperator::create(bop->getOpcode(),
+              load, ConstantSInt::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();
+    if (Ty->isSigned())
+      ci->replaceAllUsesWith(ConstantSInt::get(Ty, len));
+    else
+      ci->replaceAllUsesWith(ConstantUInt::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 (User->getOpcode() == Instruction::SetNE ||
+        User->getOpcode() == Instruction::SetEQ) {
+      if (isa<Constant>(User->getOperand(1)) && 
+          cast<Constant>(User->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->getRawValue();
+      
+    // 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 = new CastInst(LHS, UCharPtr, LHS->getName(), CI);
+      CastInst *Op2Cast = new CastInst(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 = new CastInst(RV, CI->getType(), 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 = new CastInst(LHS, UCharPtr, LHS->getName(), CI);
+        CastInst *Op2Cast = new CastInst(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(G1, 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 = new CastInst(Or, CI->getType(), 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.
@@ -937,16 +1099,13 @@ struct LLVMMemCpyOptimization : public LibCallOptimization
 {
   /// @brief Default Constructor
   LLVMMemCpyOptimization() : LibCallOptimization("llvm.memcpy",
-      "simplify-libcalls:llvm.memcpy",
       "Number of 'llvm.memcpy' calls simplified") {}
 
 protected:
-  /// @brief Subclass Constructor 
-  LLVMMemCpyOptimization(const char* fname, const char* sname, const char* desc)
-    : LibCallOptimization(fname, sname, desc) {}
+  /// @brief Subclass Constructor
+  LLVMMemCpyOptimization(const char* fname, const char* desc)
+    : LibCallOptimization(fname, desc) {}
 public:
-  /// @brief Destructor
-  virtual ~LLVMMemCpyOptimization() {}
 
   /// @brief Make sure that the "memcpy" function has the right prototype
   virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD)
@@ -998,9 +1157,9 @@ public:
     }
 
     // Cast source and dest to the right sized primitive and then load/store
-    CastInst* SrcCast = 
+    CastInst* SrcCast =
       new CastInst(src,PointerType::get(castType),src->getName()+".cast",ci);
-    CastInst* DestCast = 
+    CastInst* DestCast =
       new CastInst(dest,PointerType::get(castType),dest->getName()+".cast",ci);
     LoadInst* LI = new LoadInst(SrcCast,SrcCast->getName()+".val",ci);
     StoreInst* SI = new StoreInst(LI, DestCast, ci);
@@ -1009,32 +1168,28 @@ public:
   }
 } LLVMMemCpyOptimizer;
 
-/// This LibCallOptimization will simplify a call to the memmove library 
-/// function. It is identical to MemCopyOptimization except for the name of 
+/// 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 LLVMMemMoveOptimization : public LLVMMemCpyOptimization
 {
   /// @brief Default Constructor
   LLVMMemMoveOptimization() : LLVMMemCpyOptimization("llvm.memmove",
-      "simplify-libcalls:llvm.memmove",
       "Number of 'llvm.memmove' calls simplified") {}
 
 } LLVMMemMoveOptimizer;
 
-/// 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. 
+/// 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
   LLVMMemSetOptimization() : LibCallOptimization("llvm.memset",
-      "simplify-libcalls:llvm.memset",
       "Number of 'llvm.memset' calls simplified") {}
 
 public:
-  /// @brief Destructor
-  virtual ~LLVMMemSetOptimization() {}
 
   /// @brief Make sure that the "memset" function has the right prototype
   virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD)
@@ -1046,7 +1201,7 @@ public:
   /// 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 
+  /// 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.
@@ -1089,7 +1244,7 @@ public:
       return false;
 
     // memset(s,c,n) -> store s, c (for n=1,2,4,8)
-    
+
     // Extract the fill character
     uint64_t fill_char = FILL->getValue();
     uint64_t fill_value = fill_char;
@@ -1100,18 +1255,18 @@ public:
     Type* castType = 0;
     switch (len)
     {
-      case 1: 
-        castType = Type::UByteTy; 
+      case 1:
+        castType = Type::UByteTy;
         break;
-      case 2: 
-        castType = Type::UShortTy; 
+      case 2:
+        castType = Type::UShortTy;
         fill_value |= fill_char << 8;
         break;
-      case 4: 
+      case 4:
         castType = Type::UIntTy;
         fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
         break;
-      case 8: 
+      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;
@@ -1122,7 +1277,7 @@ public:
     }
 
     // Cast dest to the right sized primitive and then load/store
-    CastInst* DestCast = 
+    CastInst* DestCast =
       new CastInst(dest,PointerType::get(castType),dest->getName()+".cast",ci);
     new StoreInst(ConstantUInt::get(castType,fill_value),DestCast, ci);
     ci->eraseFromParent();
@@ -1130,8 +1285,8 @@ public:
   }
 } LLVMMemSetOptimizer;
 
-/// This LibCallOptimization will simplify calls to the "pow" library 
-/// function. It looks for cases where the result of pow is well known and 
+/// 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
@@ -1139,10 +1294,7 @@ struct PowOptimization : public LibCallOptimization
 public:
   /// @brief Default Constructor
   PowOptimization() : LibCallOptimization("pow",
-      "simplify-libcalls:pow", "Number of 'pow' calls simplified") {}
-
-  /// @brief Destructor
-  virtual ~PowOptimization() {}
+      "Number of 'pow' calls simplified") {}
 
   /// @brief Make sure that the "pow" function has the right prototype
   virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
@@ -1166,8 +1318,8 @@ public:
         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)
@@ -1196,7 +1348,7 @@ public:
       else if (Op2V == -1.0)
       {
         // pow(x,-1.0)    -> 1.0/x
-        BinaryOperator* div_inst= BinaryOperator::create(Instruction::Div,
+        BinaryOperator* div_inst= BinaryOperator::createDiv(
           ConstantFP::get(Ty,1.0), base, ci->getName()+".pow", ci);
         ci->replaceAllUsesWith(div_inst);
         ci->eraseFromParent();
@@ -1207,7 +1359,7 @@ public:
   }
 } PowOptimizer;
 
-/// This LibCallOptimization will simplify calls to the "fprintf" library 
+/// 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 pow library function.
@@ -1216,10 +1368,7 @@ struct FPrintFOptimization : public LibCallOptimization
 public:
   /// @brief Default Constructor
   FPrintFOptimization() : LibCallOptimization("fprintf",
-      "simplify-libcalls:fprintf", "Number of 'fprintf' calls simplified") {}
-
-  /// @brief Destructor
-  virtual ~FPrintFOptimization() {}
+      "Number of 'fprintf' calls simplified") {}
 
   /// @brief Make sure that the "fprintf" function has the right prototype
   virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
@@ -1235,14 +1384,14 @@ public:
     if (ci->getNumOperands() > 4 || ci->getNumOperands() <= 2)
       return false;
 
-    // If the result of the fprintf call is used, none of these optimizations 
+    // If the result of the fprintf call is used, none of these optimizations
     // can be made.
-    if (!ci->hasNUses(0)) 
+    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; 
+    uint64_t len = 0;
     ConstantArray* CA = 0;
     if (!getConstantStringLength(ci->getOperand(2), len, &CA))
       return false;
@@ -1258,15 +1407,22 @@ public:
           if (CI->getRawValue() == '%')
             return false; // we found end of string
         }
-        else 
+        else
           return false;
       }
 
-      // fprintf(file,fmt) -> fwrite(fmt,strlen(fmt),1file) 
+      // 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(ConstantUInt::get(SLC.getIntPtrType(),len));
@@ -1294,18 +1450,18 @@ public:
     {
       case 's':
       {
-        uint64_t len = 0; 
+        uint64_t len = 0;
         ConstantArray* CA = 0;
         if (!getConstantStringLength(ci->getOperand(3), len, &CA))
           return false;
 
-        // fprintf(file,"%s",str) -> fwrite(fmt,strlen(fmt),1,file) 
+        // fprintf(file,"%s",str) -> fwrite(fmt,strlen(fmt),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(ci->getOperand(3));
+        args.push_back(CastToCStr(ci->getOperand(3), *ci));
         args.push_back(ConstantUInt::get(SLC.getIntPtrType(),len));
         args.push_back(ConstantUInt::get(SLC.getIntPtrType(),1));
         args.push_back(ci->getOperand(1));
@@ -1336,8 +1492,7 @@ public:
   }
 } FPrintFOptimizer;
 
-
-/// This LibCallOptimization will simplify calls to the "sprintf" library 
+/// 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 pow library function.
@@ -1346,10 +1501,7 @@ struct SPrintFOptimization : public LibCallOptimization
 public:
   /// @brief Default Constructor
   SPrintFOptimization() : LibCallOptimization("sprintf",
-      "simplify-libcalls:sprintf", "Number of 'sprintf' calls simplified") {}
-
-  /// @brief Destructor
-  virtual ~SPrintFOptimization() {}
+      "Number of 'sprintf' calls simplified") {}
 
   /// @brief Make sure that the "fprintf" function has the right prototype
   virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
@@ -1367,7 +1519,7 @@ public:
 
     // 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; 
+    uint64_t len = 0;
     ConstantArray* CA = 0;
     if (!getConstantStringLength(ci->getOperand(2), len, &CA))
       return false;
@@ -1392,14 +1544,14 @@ public:
           if (CI->getRawValue() == '%')
             return false; // we found a %, can't optimize
         }
-        else 
+        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) 
+      // sprintf(str,fmt) -> llvm.memcpy(str,fmt,strlen(fmt),1)
       Function* memcpy_func = SLC.get_memcpy();
       if (!memcpy_func)
         return false;
@@ -1426,61 +1578,55 @@ public:
 
     // Get the second character and switch on its value
     ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
-    switch (CI->getRawValue())
-    {
-      case 's':
-      {
-        uint64_t len = 0;
-        if (ci->hasNUses(0))
-        {
-          // sprintf(dest,"%s",str) -> strcpy(dest,str) 
-          Function* strcpy_func = SLC.get_strcpy();
-          if (!strcpy_func)
-            return false;
-          std::vector<Value*> args;
-          args.push_back(ci->getOperand(1));
-          args.push_back(ci->getOperand(3));
-          new CallInst(strcpy_func,args,"",ci);
-        }
-        else if (getConstantStringLength(ci->getOperand(3),len))
-        {
-          // sprintf(dest,"%s",cstr) -> llvm.memcpy(dest,str,strlen(str),1)
-          len++; // get the null-terminator
-          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(3));
-          args.push_back(ConstantUInt::get(Type::UIntTy,len));
-          args.push_back(ConstantUInt::get(Type::UIntTy,1));
-          new CallInst(memcpy_func,args,"",ci);
-          ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,len));
-        }
-        break;
-      }
-      case 'c':
-      {
-        // sprintf(dest,"%c",chr) -> store chr, dest
-        CastInst* cast = 
-          new CastInst(ci->getOperand(3),Type::SByteTy,"char",ci);
-        new StoreInst(cast, ci->getOperand(1), ci);
-        GetElementPtrInst* gep = new GetElementPtrInst(ci->getOperand(1),
-          ConstantUInt::get(Type::UIntTy,1),ci->getOperand(1)->getName()+".end",
-          ci);
-        new StoreInst(ConstantInt::get(Type::SByteTy,0),gep,ci);
-        ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,1));
-        break;
-      }
-      default:
+    switch (CI->getRawValue()) {
+    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() != Type::UIntTy)
+        Len1 = new CastInst(Len1, Type::UIntTy, 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(ConstantUInt::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 = new CastInst(Len, ci->getType(), Len->getName(), ci);
+        ci->replaceAllUsesWith(Len);
+      }
+      ci->eraseFromParent();
+      return true;
     }
-    ci->eraseFromParent();
-    return true;
+    case 'c': {
+      // sprintf(dest,"%c",chr) -> store chr, dest
+      CastInst* cast = new CastInst(ci->getOperand(3),Type::SByteTy,"char",ci);
+      new StoreInst(cast, ci->getOperand(1), ci);
+      GetElementPtrInst* gep = new GetElementPtrInst(ci->getOperand(1),
+        ConstantUInt::get(Type::UIntTy,1),ci->getOperand(1)->getName()+".end",
+        ci);
+      new StoreInst(ConstantInt::get(Type::SByteTy,0),gep,ci);
+      ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,1));
+      ci->eraseFromParent();
+      return true;
+    }
+    }
+    return false;
   }
 } SPrintFOptimizer;
 
-/// This LibCallOptimization will simplify calls to the "fputs" library 
+/// 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 pow library function.
@@ -1489,10 +1635,7 @@ struct PutsOptimization : public LibCallOptimization
 public:
   /// @brief Default Constructor
   PutsOptimization() : LibCallOptimization("fputs",
-      "simplify-libcalls:fputs", "Number of 'fputs' calls simplified") {}
-
-  /// @brief Destructor
-  virtual ~PutsOptimization() {}
+      "Number of 'fputs' calls simplified") {}
 
   /// @brief Make sure that the "fputs" function has the right prototype
   virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
@@ -1505,12 +1648,12 @@ public:
   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;
 
@@ -1534,7 +1677,7 @@ public:
         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);
@@ -1554,7 +1697,84 @@ 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->getRawValue();
+      if (val >= '0' && val <='9')
+        ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,1));
+      else
+        ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,0));
+      ci->eraseFromParent();
+      return true;
+    }
+
+    // isdigit(c)   -> (unsigned)c - '0' <= 9
+    CastInst* cast =
+      new CastInst(ci->getOperand(1),Type::UIntTy,
+        ci->getOperand(1)->getName()+".uint",ci);
+    BinaryOperator* sub_inst = BinaryOperator::createSub(cast,
+        ConstantUInt::get(Type::UIntTy,0x30),
+        ci->getOperand(1)->getName()+".sub",ci);
+    SetCondInst* setcond_inst = new SetCondInst(Instruction::SetLE,sub_inst,
+        ConstantUInt::get(Type::UIntTy,9),
+        ci->getOperand(1)->getName()+".cmp",ci);
+    CastInst* c2 =
+      new CastInst(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);
+    if (V->getType()->isSigned())
+      V = new CastInst(V, V->getType()->getUnsignedVersion(), V->getName(), CI);
+    Value *Cmp = BinaryOperator::createSetLT(V, ConstantUInt::get(V->getType(),
+                                                                  128),
+                                             V->getName()+".isascii", CI);
+    if (Cmp->getType() != CI->getType())
+      Cmp = new CastInst(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.
@@ -1563,10 +1783,7 @@ struct ToAsciiOptimization : public LibCallOptimization
 public:
   /// @brief Default Constructor
   ToAsciiOptimization() : LibCallOptimization("toascii",
-      "simplify-libcalls:toascii", "Number of 'toascii' calls simplified") {}
-
-  /// @brief Destructor
-  virtual ~ToAsciiOptimization() {}
+      "Number of 'toascii' calls simplified") {}
 
   /// @brief Make sure that the "fputs" function has the right prototype
   virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
@@ -1580,7 +1797,7 @@ public:
   {
     // 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();
@@ -1588,11 +1805,144 @@ 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 "fputs" 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* ci, SimplifyLibCalls& SLC)
+  {
+    if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1)))
+    {
+      // ffs(cnst)  -> bit#
+      // ffsl(cnst) -> bit#
+      // ffsll(cnst) -> bit#
+      uint64_t val = CI->getRawValue();
+      int result = 0;
+      while (val != 0) {
+        result +=1;
+        if (val&1)
+          break;
+        val >>= 1;
+      }
+      ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy, result));
+      ci->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* arg_type = ci->getOperand(1)->getType();
+    std::vector<const Type*> args;
+    args.push_back(arg_type);
+    FunctionType* llvm_cttz_type = FunctionType::get(arg_type,args,false);
+    Function* F =
+      SLC.getModule()->getOrInsertFunction("llvm.cttz",llvm_cttz_type);
+    std::string inst_name(ci->getName()+".ffs");
+    Instruction* call =
+      new CallInst(F, ci->getOperand(1), inst_name, ci);
+    if (arg_type != Type::IntTy)
+      call = new CastInst(call, Type::IntTy, inst_name, ci);
+    BinaryOperator* add = BinaryOperator::createAdd(call,
+      ConstantSInt::get(Type::IntTy,1), inst_name, ci);
+    SetCondInst* eq = new SetCondInst(Instruction::SetEQ,ci->getOperand(1),
+      ConstantSInt::get(ci->getOperand(1)->getType(),0),inst_name,ci);
+    SelectInst* select = new SelectInst(eq,ConstantSInt::get(Type::IntTy,0),add,
+      inst_name,ci);
+    ci->replaceAllUsesWith(select);
+    ci->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 LibCallOptimization will simplify calls to the "floor" library
+/// function.
+/// @brief Simplify the floor library function.
+struct FloorOptimization : public LibCallOptimization {
+  FloorOptimization()
+    : LibCallOptimization("floor", "Number of 'floor' calls simplified") {}
+  
+  /// @brief Make sure that the "floor" 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;
+  }
+  
+  virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+    // If this is a float argument passed in, convert to floorf.
+    // e.g. floor((double)FLT) -> (double)floorf(FLT).  There can be no loss of
+    // precision due to this.
+    if (CastInst *Cast = dyn_cast<CastInst>(CI->getOperand(1)))
+      if (Cast->getOperand(0)->getType() == Type::FloatTy) {
+        Value *New = new CallInst(SLC.get_floorf(), Cast->getOperand(0),
+                                  CI->getName(), CI);
+        New = new CastInst(New, Type::DoubleTy, CI->getName(), CI);
+        CI->replaceAllUsesWith(New);
+        CI->eraseFromParent();
+        if (Cast->use_empty())
+          Cast->eraseFromParent();
+        return true;
+      }
+    return false; // opt failed
+  }
+} FloorOptimizer;
+
+
+
 /// 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
@@ -1601,10 +1951,10 @@ public:
 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;
@@ -1621,7 +1971,7 @@ 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. 
+  // 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())
@@ -1631,7 +1981,7 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
     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;
@@ -1668,7 +2018,7 @@ 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. 
+  // 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)))
@@ -1690,7 +2040,17 @@ 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) {
+  const Type *SBPTy = PointerType::get(Type::SByteTy);
+  if (V->getType() != SBPTy)
+    return new CastInst(V, SBPTy, V->getName(), &IP);
+  return V;
+}
+
+// TODO:
 //   Additional cases that we need to add to this file:
 //
 // cbrt:
@@ -1704,15 +2064,6 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
 // exp, expf, expl:
 //   * exp(log(x))  -> x
 //
-// ffs, ffsl, ffsll:
-//   * ffs(cnst)     -> cnst'
-//
-// 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)
@@ -1726,14 +2077,11 @@ 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)
-//   * memcmp(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)
 //
 // pow, powf, powl:
@@ -1751,17 +2099,14 @@ 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)
 //
+// 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)
@@ -1793,14 +2138,14 @@ 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'
 //
-// 
+//
 }