Use registers to pass arguments to GenericBinaryOpStub (x64)....

src/x64/codegen-x64.h

Index: src/x64/codegen-x64.h
===================================================================
--- src/x64/codegen-x64.h	(revision 3730)
+++ src/x64/codegen-x64.h	(working copy)
@@ -667,6 +667,11 @@
   void GenerateCall(MacroAssembler* masm, Register left, Smi* right);
   void GenerateCall(MacroAssembler* masm, Smi* left, Register right);
 
+  Result GenerateCall(MacroAssembler* masm,
+                      VirtualFrame* frame,
+                      Result* left,
+                      Result* right);
+
  private:
   Token::Value op_;
   OverwriteMode mode_;
@@ -715,9 +720,8 @@
   void GenerateReturn(MacroAssembler* masm);
 
   bool ArgsInRegistersSupported() {
-    return ((op_ == Token::ADD) || (op_ == Token::SUB)
-             || (op_ == Token::MUL) || (op_ == Token::DIV))
-            && flags_ != NO_SMI_CODE_IN_STUB;
+    return (op_ == Token::ADD) || (op_ == Token::SUB)
+        || (op_ == Token::MUL) || (op_ == Token::DIV);
   }
   bool IsOperationCommutative() {
     return (op_ == Token::ADD) || (op_ == Token::MUL);
@@ -726,8 +730,8 @@
   void SetArgsInRegisters() { args_in_registers_ = true; }
   void SetArgsReversed() { args_reversed_ = true; }
   bool HasSmiCodeInStub() { return (flags_ & NO_SMI_CODE_IN_STUB) == 0; }
-  bool HasArgumentsInRegisters() { return args_in_registers_; }
-  bool HasArgumentsReversed() { return args_reversed_; }
+  bool HasArgsInRegisters() { return args_in_registers_; }
+  bool HasArgsReversed() { return args_reversed_; }
 };