Added missing attribute to Result serialization (#3037)

* Added missing attribute to Result serialization

* Fix default layout attribute

* use helper routine for optional attrs

src/ngraph/op/result.cpp

@@ -24,8 +24,9 @@
 using namespace std;
 using namespace ngraph;
 
-op::Result::Result(const shared_ptr<Node>& arg)
+op::Result::Result(const shared_ptr<Node>& arg, bool needs_default_layout)
     : Op("Result", check_single_output_args({arg}))
+    , m_needs_default_layout(needs_default_layout)
 {
     constructor_validate_and_infer_types();
     // always borrow the placement conf even the default one
@@ -44,11 +45,7 @@ shared_ptr<Node> op::Result::copy_with_new_args(const NodeVector& new_args) cons
 {
     check_new_args_count(this, new_args);
 
-    auto res = make_shared<Result>(new_args.at(0));
-    if (res)
-    {
-        res->set_needs_default_layout(m_needs_default_layout);
-    }
+    auto res = make_shared<Result>(new_args.at(0), m_needs_default_layout);
     return std::move(res);
 }
 

src/ngraph/op/result.hpp

@@ -30,7 +30,7 @@ namespace ngraph
             /// \brief Allows a value to be used as a function result.
             ///
             /// \param arg Node that produces the input tensor.
-            Result(const std::shared_ptr<Node>& arg);
+            Result(const std::shared_ptr<Node>& arg, bool needs_default_layout = false);
 
             void validate_and_infer_types() override;
 

src/ngraph/serializer.cpp

@@ -1417,7 +1417,9 @@ static shared_ptr<ngraph::Function>
             }
             case OP_TYPEID::Result:
             {
-                node = make_shared<op::Result>(args[0]);
+                auto needs_default_layout =
+                    get_or_default<bool>(node_js, "needs_default_layout", false);
+                node = make_shared<op::Result>(args[0], needs_default_layout);
                 break;
             }
             case OP_TYPEID::Reverse:
@@ -2341,7 +2343,11 @@ static json write(const Node& n, bool binary_constant_data)
         node["output_shape"] = tmp->get_output_shape();
         break;
     }
-    case OP_TYPEID::Result: { break;
+    case OP_TYPEID::Result:
+    {
+        auto tmp = dynamic_cast<const op::Result*>(&n);
+        node["needs_default_layout"] = tmp->needs_default_layout();
+        break;
     }
     case OP_TYPEID::Reverse:
     {