Fix x64 build.

bleeding_edge/src/x64/fast-codegen-x64.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 660 matching lines @@
     case Token::SAR: {
       ASSERT(expr->left()->location().is_value());
       ASSERT(expr->right()->location().is_value());
 
       Visit(expr->left());
       Visit(expr->right());
       GenericBinaryOpStub stub(expr->op(),
                                NO_OVERWRITE,
                                NO_GENERIC_BINARY_FLAGS);
       __ CallStub(&stub);
-      Move(expr->location(), kReturnRegister);
+      Move(expr->location(), rax);
 
       break;
     }
     default:
       UNREACHABLE();
   }
 }
 
 
 void FastCodeGenerator::EmitLogicalOperation(BinaryOperation* expr) {
@@ skipping 83 matching lines @@
   } else {
     Visit(right);
     Move(destination, right->location());
   }
 
   __ bind(&done);
 }
 
 
 } }  // namespace v8::internal