[TF FE] Support SaveV2 operation (#15572)

* [TF FE] Support SaveV2 operation

Also, implement transformation to remove UnsupportedConstant to Result
isolated sub-graphs

Signed-off-by: Kazantsev, Roman <roman.kazantsev@intel.com>

* Revert change for Constant

---------

Signed-off-by: Kazantsev, Roman <roman.kazantsev@intel.com>

src/frontends/tensorflow/src/frontend.cpp

@@ -8,6 +8,7 @@
 #include "helper_transforms/block_lstm_replacer.hpp"
 #include "helper_transforms/embedding_segments_feature_fusing.hpp"
 #include "helper_transforms/gru_block_cell_replacer.hpp"
+#include "helper_transforms/unsupported_const_to_result_remover.hpp"
 #include "input_model.hpp"
 #include "op_table.hpp"
 #include "openvino/frontend/tensorflow/extension/conversion.hpp"
@@ -251,6 +252,7 @@ void FrontEnd::normalize(const std::shared_ptr<ov::Model>& function) const {
     manager.register_pass<pass::EmbeddingSegmentSingleFeatureFusion>();
     manager.register_pass<pass::BlockLSTMReplacer>();
     manager.register_pass<pass::GRUBlockCellReplacer>();
+    manager.register_pass<pass::UnsupportedConstToResultRemover>();
 
     manager.register_pass<ov::pass::TransposeSinkingGeneral>();
     manager.register_pass<ov::pass::ReverseShapeAndTypeInfer>();

src/frontends/tensorflow/src/op_table.cpp

@@ -189,6 +189,7 @@ const std::map<std::string, CreatorFunction> get_supported_ops() {
         {"Roll", translate_roll_op},
         {"Round", translate_round_op},
         {"Rsqrt", translate_rsqrt_op},
+        {"SaveV2", translate_no_op},
         {"ScatterNd", translate_scatter_nd_op},
         {"SegmentSum", translate_segment_sum_op},
         {"SparseToDense", translate_sparse_to_dense_op},

src/frontends/tensorflow/tests/convert_tricky_models.cpp

@@ -246,3 +246,19 @@ TEST_F(TransformationTestsF, DISABLED_ModelWithDilatedGroupConvolution) {
         model_ref = make_shared<Model>(OutputVector{transpose_after}, ParameterVector{x});
     }
 }
+
+TEST_F(TransformationTestsF, ModelWithSaveV2) {
+    {
+        model = convert_model("model_savev2/model_savev2.pb");
+        // need to call shape inference since body graphs can be injected with undefined shapes
+        model->validate_nodes_and_infer_types();
+    }
+    {
+        // create a reference graph
+        auto x = make_shared<Parameter>(element::f32, Shape{2});
+        auto const_2 = make_shared<Constant>(element::f32, Shape{2}, vector<float>{1, 2});
+        auto add = make_shared<Add>(x, const_2);
+
+        model_ref = make_shared<Model>(OutputVector{add}, ParameterVector{x});
+    }
+}

src/frontends/tensorflow/tests/test_models/models_pbtxt/model_savev2.pbtxt

@@ -0,0 +1,152 @@
+node {
+  name: "x"
+  op: "Placeholder"
+  attr {
+    key: "dtype"
+    value {
+      type: DT_FLOAT
+    }
+  }
+  attr {
+    key: "shape"
+    value {
+      shape {
+        dim {
+          size: 2
+        }
+      }
+    }
+  }
+}
+node {
+  name: "Const"
+  op: "Const"
+  attr {
+    key: "dtype"
+    value {
+      type: DT_FLOAT
+    }
+  }
+  attr {
+    key: "value"
+    value {
+      tensor {
+        dtype: DT_FLOAT
+        tensor_shape {
+          dim {
+            size: 2
+          }
+        }
+        tensor_content: "\000\000\200?\000\000\000@"
+      }
+    }
+  }
+}
+node {
+  name: "add"
+  op: "AddV2"
+  input: "x"
+  input: "Const"
+  attr {
+    key: "T"
+    value {
+      type: DT_FLOAT
+    }
+  }
+}
+node {
+  name: "save/Const"
+  op: "Const"
+  attr {
+    key: "dtype"
+    value {
+      type: DT_STRING
+    }
+  }
+  attr {
+    key: "value"
+    value {
+      tensor {
+        dtype: DT_STRING
+        tensor_shape {
+        }
+        string_val: "model"
+      }
+    }
+  }
+}
+node {
+  name: "tensor_names"
+  op: "Const"
+  attr {
+    key: "dtype"
+    value {
+      type: DT_STRING
+    }
+  }
+  attr {
+    key: "value"
+    value {
+      tensor {
+        dtype: DT_STRING
+        tensor_shape {
+          dim {
+            size: 1
+          }
+        }
+        string_val: "Const"
+      }
+    }
+  }
+}
+node {
+  name: "shape_and_slices"
+  op: "Const"
+  attr {
+    key: "dtype"
+    value {
+      type: DT_STRING
+    }
+  }
+  attr {
+    key: "value"
+    value {
+      tensor {
+        dtype: DT_STRING
+        tensor_shape {
+          dim {
+            size: 1
+          }
+        }
+        string_val: ""
+      }
+    }
+  }
+}
+node {
+  name: "SaveV2"
+  op: "SaveV2"
+  input: "save/Const"
+  input: "tensor_names"
+  input: "shape_and_slices"
+  input: "Const"
+  attr {
+    key: "dtypes"
+    value {
+      list {
+        type: DT_FLOAT
+      }
+    }
+  }
+}
+node {
+  name: "save/control_dependency"
+  op: "Identity"
+  input: "save/Const"
+  attr {
+    key: "T"
+    value {
+      type: DT_STRING
+    }
+  }
+}

src/frontends/tensorflow_common/include/helper_transforms/unsupported_const_to_result_remover.hpp

@@ -0,0 +1,26 @@
+// Copyright (C) 2018-2023 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+//
+
+#pragma once
+
+#include "openvino/pass/pass.hpp"
+
+namespace ov {
+namespace frontend {
+namespace tensorflow {
+namespace pass {
+
+// This transformation removes isolated subgraph Unsupported constant going to the Result node
+class UnsupportedConstToResultRemover : public ov::pass::ModelPass {
+public:
+    OPENVINO_RTTI("ov::frontend::tensorflow::pass::UnsupportedConstToResultRemover");
+    UnsupportedConstToResultRemover() {}
+
+    bool run_on_model(const std::shared_ptr<ov::Model>& m) override;
+};
+
+}  // namespace pass
+}  // namespace tensorflow
+}  // namespace frontend
+}  // namespace ov

src/frontends/tensorflow_common/src/helper_transforms/unsupported_const_to_result_remover.cpp

@@ -0,0 +1,36 @@
+// Copyright (C) 2018-2023 Intel Corporation
+// SPDX-License-Identifier: Apache-2.0
+//
+
+#include "helper_transforms/unsupported_const_to_result_remover.hpp"
+
+#include "helper_ops/unsupported_constant.hpp"
+
+using namespace std;
+
+namespace ov {
+namespace frontend {
+namespace tensorflow {
+namespace pass {
+
+bool UnsupportedConstToResultRemover::run_on_model(const std::shared_ptr<ov::Model>& m) {
+    ResultVector results_to_remove;
+    // look for isolated UnsupportedConst->Result sub-graphs to remove
+    for (const auto& result : m->get_results()) {
+        auto unsupported_const = as_type_ptr<UnsupportedConstant>(result->get_input_node_shared_ptr(0));
+        if (unsupported_const && unsupported_const->output(0).get_target_inputs().size() == 1) {
+            results_to_remove.push_back(result);
+        }
+    }
+
+    for (const auto& result : results_to_remove) {
+        m->remove_result(result);
+    }
+
+    return true;
+}
+
+}  // namespace pass
+}  // namespace tensorflow
+}  // namespace frontend
+}  // namespace ov

src/frontends/tensorflow_common/src/op/no_op.cpp

@@ -14,18 +14,9 @@ namespace tensorflow {
 namespace op {
 
 OutputVector translate_no_op(const NodeContext& node) {
-    if (node.get_input_size() == 0) {
-        return OutputVector{};
-    }
-
-    TENSORFLOW_OP_VALIDATION(node,
-                             node.get_input_size() == 1,
-                             "NoOp has " + to_string(node.get_input_size()) + " inputs, should have 1");
-
-    auto input = node.get_input(0);
-    set_out_name(node.get_name(), input);
-    set_out_name(node.get_name() + ":" + "0", input);
-    return {input};
+    // the operation does nothing in terms of data generation
+    default_op_checks(node, 0, {"NoOp", "SaveV2"});
+    return {};
 }
 }  // namespace op
 }  // namespace tensorflow