libjulia/optimiser/CommonSubexpressionEliminator.cpp


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/*(
    This file is part of solidity.

    solidity is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    solidity is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with solidity.  If not, see <http://www.gnu.org/licenses/>.
*/
/**
 * Optimisation stage that replaces expressions known to be the current value of a variable
 * in scope by a reference to that variable.
 */

#include <libjulia/optimiser/CommonSubexpressionEliminator.h>

#include <libjulia/optimiser/Metrics.h>
#include <libjulia/optimiser/SyntacticalEquality.h>
#include <libjulia/Exceptions.h>

#include <libsolidity/inlineasm/AsmData.h>

using namespace std;
using namespace dev;
using namespace dev::julia;

void CommonSubexpressionEliminator::visit(Expression& _e)
{
    // Single exception for substitution: We do not substitute one variable for another.
    if (_e.type() != typeid(Identifier))
        // TODO this search rather inefficient.
        for (auto const& var: m_value)
        {
            assertThrow(var.second, OptimizerException, "");
            if (SyntacticalEqualityChecker::equal(_e, *var.second))
            {
                _e = Identifier{locationOf(_e), var.first};
                break;
            }
        }
    DataFlowAnalyzer::visit(_e);
}