Since this is still dribbling along I'll point out intobject.c:int_pow() and:

        prev = ix;              /* Save value for overflow check */
        if (iw & 1) {
            ix = ix*temp;
            if (temp == 0)
                break; /* Avoid ix / 0 */
            if (ix / temp != prev) {
                return PyLong_Type.tp_as_number->nb_power(
                    (PyObject *)v,
                    (PyObject *)w,
                    (PyObject *)z);
            }
        }

which I misclassified in http://bugs.python.org/issue12701