Add initial integrated assembler w/ some Xmm ops.

src/IceDefs.h

 //===- subzero/src/IceDefs.h - Common Subzero declaraions -------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares various useful types and classes that have
@@ skipping 111 matching lines @@
     return End.getWallTime() - Start.getWallTime();
   }
   void printElapsedUs(GlobalContext *Ctx, const IceString &Tag) const;
 
 private:
   const llvm::TimeRecord Start;
   Timer(const Timer &) LLVM_DELETED_FUNCTION;
   Timer &operator=(const Timer &) LLVM_DELETED_FUNCTION;
 };
 
-template <typename T> bool WouldOverflowAdd(T X, T Y) {
-  return ((X > 0 && Y > 0 && (X > std::numeric_limits<T>::max() - Y)) ||
-          (X < 0 && Y < 0 && (X < std::numeric_limits<T>::min() - Y)));
-}
-
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEDEFS_H