message: Check if node is nullptr.
diff: @@ -976,6 +976,8 @@ class MklLayoutRewritePass : public GraphOptimizationPass {
  }
  static bool CheckForMklOp(const Node* node, string name = "") {
  + if (node == nullptr) return false;
  +
  if (!name.empty() && node->type_string() != name) {
  return false;
  }
  