Function IsReachable

tensorflow/compiler/jit/graphcycles/graphcycles_test.cc:43–59

Return whether "to" is reachable from "from".

// Return whether "to" is reachable from "from".
static bool IsReachable(Edges *edges, int from, int to,
                        std::unordered_set<int> *seen) {
  seen->insert(from);  // we are investigating "from"; don't do it again
  if (from == to) return true;
  for (int i = 0; i != edges->size(); i++) {
    Edge *edge = &(*edges)[i];
    if (edge->from == from) {
      if (edge->to == to) {  // success via edge directly
        return true;
      } else if (seen->find(edge->to) == seen->end() &&  // success via edge
                 IsReachable(edges, edge->to, to, seen)) {
        return true;
      }
    }
  }
  return false;
}

static void PrintNodes(Nodes *nodes) {
  LOG(INFO) << "NODES (" << nodes->size() << ")";