make sure Slice is reshaped if needed (#1803)

src/ngraph/runtime/cpu/pass/cpu_mat_fusion.cpp

@@ -147,6 +147,13 @@ bool runtime::cpu::pass::CPURnnMatFusion::run_on_function(std::shared_ptr<Functi
             auto matched_weight = matcher_v2->get_pattern_map()[W]->get_argument(0);
             auto matched_data = matcher_v2->get_pattern_map()[input_data];
             auto matched_bias = matcher_v2->get_pattern_map()[b]->get_argument(0);
+            if (matcher_v2->get_match_root()->get_shape().size() != 2 &&
+                matcher_v2->get_match_root()->get_shape().size() != 3)
+            {
+                NGRAPH_DEBUG << "mat fusion (v2) root " << matcher_v2->get_match_root()->get_name()
+                             << " isn't 2D or 3D";
+                continue;
+            }
             map_weights_to_pattern[matched_weight].push_back(matcher_v2->get_match_root());
             map_weights_bias_to_data[std::make_pair(matched_weight, matched_bias)].push_back(
                 matched_data);
@@ -248,8 +255,15 @@ bool runtime::cpu::pass::CPURnnMatFusion::run_on_function(std::shared_ptr<Functi
             size_t end_index = batch_size;
             for (auto& matched_root_node : map_weights_to_pattern[weights])
             {
-                auto slice_node = std::make_shared<op::Slice>(
+                std::shared_ptr<Node> slice_node = std::make_shared<op::Slice>(
                     new_add_bias, Coordinate{start_index, 0}, Coordinate{end_index, shape_axis_1});
+
+                if (matched_root_node->get_shape().size() != 2)
+                {
+                    NGRAPH_ASSERT(matched_root_node->get_shape().size() == 3);
+                    slice_node = std::make_shared<op::Reshape>(
+                        slice_node, AxisVector{0, 1}, matched_root_node->get_shape());
+                }
                 start_index += batch_size;
                 end_index += batch_size;
                 NGRAPH_DEBUG << "Replacing op " << matched_root_node->get_name() << " with "