[MO] Support TF2 Keras ConvLSTM2D operation

model-optimizer/automation/package_BOM.txt

@@ -569,6 +569,7 @@ extensions/middle/LayoutChangeForConstantShapePaths.py
 extensions/middle/LeakyReluPattern.py
 extensions/middle/LSTMRNNSequenceToTensorIterator.py
 extensions/middle/MarkSubgraphsWithCorrectLayout.py
+extensions/middle/MoveConstToLoopBody.py
 extensions/middle/MulFakeQuantizeFuse.py
 extensions/middle/MXNetRNNSequenceNormalize.py
 extensions/middle/MXNetSplitMultiLayers.py

model-optimizer/extensions/middle/MoveConstToLoopBody.py

@@ -0,0 +1,58 @@
+"""
+ Copyright (C) 2017-2021 Intel Corporation
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+"""
+
+from extensions.ops.loop import Loop
+from mo.middle.replacement import MiddleReplacementPattern
+from mo.graph.graph import Graph
+
+
+class MoveConstToLoopBody(MiddleReplacementPattern):
+    """
+    It moves constant producers for Loop node into the body graph and removes input ports for them.
+    This transformations helps to continue constant folding inside the body graph if possible.
+    The constant folding serves as optimization path and helps to avoid issue connecting with constants
+    lying on weights path to Convolution node.
+    """
+    enabled = True
+    force_shape_inference = True
+
+    def run_after(self):
+        from extensions.middle.pass_separator import PostMiddleStart
+        return [PostMiddleStart]
+
+    def run_before(self):
+        from extensions.middle.ApplyPermutations import ApplyPermutation
+        return [ApplyPermutation]
+
+    def find_and_replace_pattern(self, graph: Graph):
+        cleanup_called_once = False
+
+        # walk through all Loop nodes and find Const inputs
+        for loop_node in graph.get_op_nodes(op='Loop'):
+            # call clean-up only once that performs constant folding
+            if not cleanup_called_once:
+                graph.clean_up()
+                cleanup_called_once = True
+
+            # move constant node into the body graph and removes body parameter nodes corresponding to them
+            Loop.pull_constant_inputs_into_body(loop_node)
+
+            # since some input ports can be removed after the pulling constants, normalization of Loop node is required
+            Loop.normalize_input_output_ports(loop_node)
+
+            # perform shape inference for the Loop node again since new constant can be appeared
+            # and constant folding can be helpful for weights path to Convolution node inside the body graph
+            loop_node['need_shape_inference'] = True

model-optimizer/extensions/middle/fusings.py

@@ -1,5 +1,5 @@
 """
- Copyright (C) 2018-2020 Intel Corporation
+ Copyright (C) 2018-2021 Intel Corporation
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -96,7 +96,7 @@ def find_and_replace_pattern(self, graph: Graph):
                 for_graph_and_each_sub_graph_recursively(graph, fuse_linear_ops)
                 for_graph_and_each_sub_graph_recursively(graph, lambda G: G.clean_up())
 
-        normalize_eltwise_inputs(graph)
+        for_graph_and_each_sub_graph_recursively(graph, normalize_eltwise_inputs)
         for_graph_and_each_sub_graph_recursively(graph, lambda G: G.clean_up())
 
         MarkNodesToFuseUpToFakeQuantize().find_and_replace_pattern(graph)

model-optimizer/extensions/ops/loop.py

@@ -315,8 +315,7 @@ def add_back_edge(loop_node: Node, internal_parameter: Node, internal_result: No
     @staticmethod
     def pull_constant_inputs_into_body(loop_node: Node):
         for port_idx, in_port in reversed(loop_node.in_ports().items()):
-            # TODO add a check that the input does not correspond to execution_condition
-            if not in_port.disconnected() and in_port.get_source().node.soft_get('type') == 'Const':
+            if port_idx > 1 and not in_port.disconnected() and in_port.get_source().node.soft_get('type') == 'Const':
                 original_const_node = in_port.get_source().node
                 new_const_node = Const(loop_node.body, original_const_node.attrs()).create_node()
 
@@ -463,7 +462,7 @@ def remove_unused_ops_from_port_map(loop_node: Node, port_map: dict, port_map_at
                 port_to_remove = port_map[record_id_to_remove]['external_port_id']
                 if port_to_remove != -1:
                     if dir == 'in':
-                        if port_to_remove not in [0, 1]:  # input port 0 and 1 are mandatory for the Loop node
+                        if port_to_remove not in [0, 1] and port_to_remove in loop_node.in_ports().keys():  # input port 0 and 1 are mandatory for the Loop node
                             loop_node.delete_input_port(port_to_remove)
                     elif dir == 'out' and port_to_remove in loop_node.out_ports():
                         loop_node.delete_output_port(port_to_remove)

model-optimizer/mo/graph/connection.py

@@ -212,8 +212,8 @@ def check_and_remove_edge():
                             "Broken Connection object! Destination (node:{}) is not connected to source.".format(
                                 destination.node.name))
                     destination.disconnect()
-                    return edge_attrs
-            return None
+                    return edge_attrs, key
+            return {}, None
 
         if self.destinations and len(self.destinations) > 1:
             raise Error("set_destination applicable only for connections that has exactly one destination or \
@@ -228,7 +228,7 @@ def check_and_remove_edge():
         if self.graph.stage == 'front':
             if self.source is not None:
                 node = self.source.node
-                source_attrs = check_and_remove_edge() or {}
+                source_attrs, _ = check_and_remove_edge()
                 dest_attrs = port.get_in_edge_attrs() or {}
 
                 edge_attrs = {}
@@ -243,7 +243,7 @@ def check_and_remove_edge():
             # in case if data node exists just use it as is
             if self.source is not None:
                 data_node = self.source._create_data_if_necessary()
-                edge_attrs = check_and_remove_edge() or {}
+                edge_attrs, key = check_and_remove_edge()
                 edge_attrs.update({'in': port.idx})
 
                 dest_attrs = {}
@@ -253,7 +253,7 @@ def check_and_remove_edge():
                 new_tensor_info = self._get_new_tensor_debug_info(attributes_save_mode, data_node.attrs(), dest_attrs)
                 self._update_tensor_debug_info(data_node.attrs(), new_tensor_info)
 
-                self.graph.add_edge(data_node.id, port.node.id, **edge_attrs)
+                self.graph.add_edge(data_node.id, port.node.id, key=key, **edge_attrs)
             self.destinations = [port]
 
     def add_destination(self, port):