src/graph/mutators/InPlaceOperationMutator.cpp

/*
 * Copyright (c) 2018 ARM Limited.
 *
 * SPDX-License-Identifier: MIT
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include "arm_compute/graph/mutators/InPlaceOperationMutator.h"

#include "arm_compute/graph/Graph.h"
#include "arm_compute/graph/Logger.h"

namespace arm_compute
{
namespace graph
{
const char *InPlaceOperationMutator::name()
{
    return "InPlaceOperationMutator";
}

void InPlaceOperationMutator::mutate(Graph &g)
{
    std::set<NodeType> in_place_nodes = { NodeType::BatchNormalizationLayer, NodeType::ActivationLayer };

    // Not interested in the order of nodes
    for(auto &node : g.nodes())
    {
        if(node && in_place_nodes.find(node->type()) != std::end(in_place_nodes))
        {
            // Get input edge
            Edge *input_edge = node->input_edge(0);

            // Check if parent has a single output if yes then force in place calculation else not
            if((input_edge != nullptr) && (input_edge->producer() != nullptr) && (input_edge->producer()->output_edges().size() == 1))
            {
                // Get current and new output tensors
                auto current_output_tensor = node->output(0);
                auto new_output_tensor     = input_edge->tensor();

                ARM_COMPUTE_ERROR_ON(current_output_tensor == nullptr || new_output_tensor == nullptr);

                // Prevent in-place operation if there is an accessor bound to the in-place tensor
                if(new_output_tensor->accessor() == nullptr)
                {
                    ARM_COMPUTE_LOG_GRAPH_VERBOSE("Switching to in-place computation for the node with ID : "
                                                  << node->id() << " and name : " << node->name() << std::endl);
                    // Update accessor
                    new_output_tensor->set_accessor(current_output_tensor->extract_accessor());
                    // Update output
                    node->set_output_tensor(new_output_tensor->id(), 0);
                }
                else
                {
                    ARM_COMPUTE_LOG_GRAPH_VERBOSE("Prevented in-place operation as there is an accessor bound to the input tensor\n");
                }
            }
        }
    }
}
} // namespace graph
} // namespace arm_compute