Take care of those loop headers/tails where we manually broke their
        connection to the next BBL

def _pd_post_process(self, cfg):
        """
        Take care of those loop headers/tails where we manually broke their
        connection to the next BBL
        """
        loop_back_edges = self._cfg.get_loop_back_edges()

        for b1, b2 in loop_back_edges:
            # The edge between b1 and b2 is manually broken
            # The post dominator of b1 should be b2 (or not?)

            successors = list(self._pd_graph_successors(cfg, b1))

            if len(successors) == 0:
                if b2 in self._post_dom:
                    self._post_dom.add_edge(b1, b2)
                else:
                    _l.debug("%s is not in post dominator dict.", b2)