Add identity shortcut to PyObject_RichCompareBool.

Objects/object.c

@@ -871,9 +871,19 @@ Done:
 int
 PyObject_RichCompareBool(PyObject *v, PyObject *w, int op)
 {
-	PyObject *res = PyObject_RichCompare(v, w, op);
+	PyObject *res;
 	int ok;
 
+	/* Quick result when objects are the same.
+	   Guarantees that identity implies equality. */
+	if (v == w) {
+		if (op == Py_EQ)
+			return 1;
+		else if (op == Py_NE)
+			return 0;
+	}
+
+	res = PyObject_RichCompare(v, w, op);
 	if (res == NULL)
 		return -1;
 	if (PyBool_Check(res))