Revert accidental change from r7795 that was causing a bug fixed in r7790 to reappear.

Review URL: http://codereview.chromium.org/6968010

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7931 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x64/code-stubs-x64.cc

@@ -1010,7 +1010,7 @@ void TypeRecordingBinaryOpStub::GenerateFloatingPointCode(
         // We need tagged values in rdx and rax for the following code,
         // not int32 in rax and rcx.
         __ Integer32ToSmi(rax, rcx);
-        __ Integer32ToSmi(rdx, rax);
+        __ Integer32ToSmi(rdx, rbx);
         __ jmp(allocation_failure);
       }
       break;