Adding unary op optimizations. missing assembly operations/

runtime/vm/assembler_x64.h

Index: runtime/vm/assembler_x64.h
===================================================================
--- runtime/vm/assembler_x64.h	(revision 8118)
+++ runtime/vm/assembler_x64.h	(working copy)
@@ -457,11 +457,15 @@
 
   void negl(Register reg);
   void negq(Register reg);
+  void notl(Register reg);
+  void notq(Register reg);
 
   void enter(const Immediate& imm);
   void leave();
   void ret();
 
+  void xorpd(XmmRegister dst, const Address& src);
+
   // 'size' indicates size in bytes and must be in the range 1..8.
   void nop(int size = 1);
   void int3();
@@ -519,6 +523,17 @@
   void CallRuntime(const RuntimeEntry& entry);
 
   /*
+   * Loading and comparing classes of objects.
+   */
+  void LoadClassId(Register result, Register object);
+
+  void LoadClassById(Register result, Register class_id);
+
+  void LoadClass(Register result, Register object);
+
+  void CompareClassId(Register object, intptr_t class_id);
+
+  /*
    * Misc. functionality.
    */
   void SmiTag(Register reg) {