From 63dd0685fce0eaaf788d0e6cd5ee1950775c6e1f Mon Sep 17 00:00:00 2001
From: Pavel Esir <pavel.esir@intel.com>
Date: Mon, 13 Feb 2023 05:00:29 +0100
Subject: [PATCH] [IE][nG][LoadTime] speed up constant folding (#15476)

* speed up constant folding and improved load time for FP16

* fix unit-tests

* added OPENVINO_SUPPRESS_DEPRECATED_START

* new evaluate for Convert; added constructor for Constant; constant copying by reference during constant_fold

* removed deprecation macro from Convert evaluate

* returned back Convert evaluate to old HostTensorPtr because it's used in tests accuracy comparator
---
 src/core/include/openvino/op/constant.hpp |  4 ++++
 src/core/src/node.cpp                     |  8 +++-----
 src/core/src/op/constant.cpp              | 11 +++++++++++
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/core/include/openvino/op/constant.hpp b/src/core/include/openvino/op/constant.hpp
index a603c6d7d67..b9976269abf 100644
--- a/src/core/include/openvino/op/constant.hpp
+++ b/src/core/include/openvino/op/constant.hpp
@@ -30,6 +30,10 @@ public:
     /// \param tensor The tensor with data
     Constant(const std::shared_ptr<ngraph::runtime::Tensor>& tensor);
 
+    /// \brief Initialize a constant from ov::Tensor
+    /// \param tensor The ov::Tensor with data
+    Constant(const ov::Tensor& tensor);
+
     /// \brief Constructs a tensor constant.
     ///
     /// \param type The element type of the tensor constant.
diff --git a/src/core/src/node.cpp b/src/core/src/node.cpp
index c78cca9434b..ca789560aca 100644
--- a/src/core/src/node.cpp
+++ b/src/core/src/node.cpp
@@ -794,8 +794,8 @@ bool ov::Node::constant_fold(OutputVector& output_values, const OutputVector& in
     for (const auto& input : input_values) {
         nodes.push_back(input.get_node_shared_ptr());
         auto constant = ov::as_type_ptr<ngraph::op::v0::Constant>(input.get_node_shared_ptr());
-        auto tensor = ov::Tensor(input.get_element_type(), input.get_shape());
-        std::copy_n(constant->get_data_ptr<uint8_t>(), constant->get_byte_size(), static_cast<uint8_t*>(tensor.data()));
+        void* data = (void*)constant->get_data_ptr();
+        auto tensor = ov::Tensor(input.get_element_type(), input.get_shape(), data);
         input_tensors.push_back(tensor);
     }
 
@@ -807,9 +807,7 @@ bool ov::Node::constant_fold(OutputVector& output_values, const OutputVector& in
     OPENVINO_SUPPRESS_DEPRECATED_START
     if (evaluate(output_tensors, input_tensors)) {
         for (size_t i = 0; i < output_tensors.size(); ++i) {
-            output_values[i] = make_shared<ngraph::op::Constant>(output_tensors[i].get_element_type(),
-                                                                 output_tensors[i].get_shape(),
-                                                                 output_tensors[i].data());
+            output_values[i] = make_shared<ngraph::op::Constant>(output_tensors[i]);
             copy_runtime_info(nodes, output_values[i].get_node_shared_ptr());
         }
         return true;
diff --git a/src/core/src/op/constant.cpp b/src/core/src/op/constant.cpp
index 42b99b11a56..4d695cd7d58 100644
--- a/src/core/src/op/constant.cpp
+++ b/src/core/src/op/constant.cpp
@@ -50,6 +50,17 @@ ov::op::v0::Constant::Constant(const shared_ptr<ngraph::runtime::Tensor>& tensor
     constructor_validate_and_infer_types();
 }
 
+ov::op::v0::Constant::Constant(const ov::Tensor& tensor) {
+    m_element_type = tensor.get_element_type();
+    m_shape = tensor.get_shape();
+    // Share data from ov::Tensor
+    m_data = make_shared<ngraph::runtime::SharedBuffer<ov::Tensor>>(static_cast<char*>(tensor.data()),
+                                                                    tensor.get_byte_size(),
+                                                                    tensor);
+
+    constructor_validate_and_infer_types();
+}
+
 ov::op::v0::Constant::Constant(const element::Type& type,
                                const ov::Shape& shape,
                                const std::vector<std::string>& values)