message: [Graph] bug fix
diff: @@ -2495,6 +2495,8 @@ void FFModel::graph_optimize(size_t budget,
  bool FFModel::convert_graph_to_operators(const Graph* graph,
  const std::unordered_map<Node, MachineView>& optimal_views)
  {
  + // Clear operators
  + operators.clear();
  std::unordered_map<Node, int> todos;
  std::unordered_map<Node, Op*> node_to_op;
  std::vector<Node> queue;
  