message: Fix segmentation fault for CONV_2D with dilation.
diff: @@ -86,7 +86,7 @@ bool ResolveDilatedConv(Model* model, Operator* conv_base_op, Operator* stb_op,
  ? GetOpWithInput(*model, post_conv_op->outputs[0])
  : GetOpWithInput(*model, conv_op->outputs[0]);
  bool has_pad_op = false;
  - if (pad_op->type == OperatorType::kPad) {
  + if (pad_op && pad_op->type == OperatorType::kPad) {
  has_pad_op = true;
  CHECK_EQ(pad_op->inputs.size(), 2);
  CHECK_EQ(pad_op->outputs.size(), 1);
  @@ -128,7 +128,7 @@ bool ResolveDilatedConv(Model* model, Operator* conv_base_op, Operator* stb_op,
  if (!has_pad_op) {
  auto* pre_stb_pad_op = GetOpWithOutput(*model, stb_op->inputs[0]);
  // If it is a Pad Op then just rewire the Input of Pad Op with Input of STB
  - if (pre_stb_pad_op->type == OperatorType::kPad) {
  + if (pre_stb_pad_op && pre_stb_pad_op->type == OperatorType::kPad) {
  stb_op->inputs[0] = pre_stb_pad_op->inputs[0];
  has_pad_op = true;
  pad_op = pre_stb_pad_op;
  