Tweak SmiSub for X64

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 09dae3e09608b248886bd0a7b47a783a9171d25b..646d7fafc0a575f81ef93f42741512883893de91 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -596,18 +596,13 @@ class MacroAssembler: public Assembler {
               Register src2);
 
   // Subtracts smi values and return the result as a smi.
-  // If dst is src1, then src1 will be destroyed, even if
-  // the operation is unsuccessful.
+  // If dst is src1, then src1 will be destroyed if the operation is
+  // successful, otherwise kept intact.
   void SmiSub(Register dst,
               Register src1,
               Register src2,
               Label* on_not_smi_result,
               Label::Distance near_jump = Label::kFar);
-
-  void SmiSub(Register dst,
-              Register src1,
-              Register src2);
-
   void SmiSub(Register dst,
               Register src1,
               const Operand& src2,
@@ -616,6 +611,10 @@ class MacroAssembler: public Assembler {
 
   void SmiSub(Register dst,
               Register src1,
+              Register src2);
+
+  void SmiSub(Register dst,
+              Register src1,
               const Operand& src2);
 
   // Multiplies smi values and return the result as a smi,