Add initial integrated assembler w/ some Xmm ops.

src/IceDefs.h

Index: src/IceDefs.h
diff --git a/src/IceDefs.h b/src/IceDefs.h
index 0f200bcd10b364e58122698af1dbbe010541e71b..322e9b43322b6016e7383d0c5d448adb8c4d3bd8 100644
--- a/src/IceDefs.h
+++ b/src/IceDefs.h
@@ -130,11 +130,6 @@ private:
   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