Fix SmiCompare on 64 bit to distinguish between comparisons where...

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
===================================================================
--- src/x64/macro-assembler-x64.h	(revision 7153)
+++ src/x64/macro-assembler-x64.h	(working copy)
@@ -278,8 +278,9 @@
                                            int power);
 
 
-  // Simple comparison of smis.
-  void SmiCompare(Register dst, Register src);
+  // Simple comparison of smis.  Both sides must be known smis to use these,
+  // otherwise use Cmp.
+  void SmiCompare(Register smi1, Register smi2);
   void SmiCompare(Register dst, Smi* src);
   void SmiCompare(Register dst, const Operand& src);
   void SmiCompare(const Operand& dst, Register src);
@@ -609,6 +610,8 @@
   void Move(const Operand& dst, Handle<Object> source);
   void Cmp(Register dst, Handle<Object> source);
   void Cmp(const Operand& dst, Handle<Object> source);
+  void Cmp(Register dst, Smi* src);
+  void Cmp(const Operand& dst, Smi* src);
   void Push(Handle<Object> source);
 
   // Emit code to discard a non-negative number of pointer-sized elements
@@ -702,6 +705,7 @@
 
   // Abort execution if argument is not a smi. Used in debug code.
   void AbortIfNotSmi(Register object);
+  void AbortIfNotSmi(const Operand& object);
 
   // Abort execution if argument is a string. Used in debug code.
   void AbortIfNotString(Register object);