/*

  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/>.

*/

// SPDX-License-Identifier: GPL-3.0

#include <libyul/backends/evm/ssa/PhiInverse.h>

using namespace solidity::yul::ssa;

PhiInverse::PhiInverse(SSACFG const& _cfg, SSACFG::BlockId const& _from, SSACFG::BlockId const& _to)

{

  _cfg.forEachUpsilon(_cfg.block(_from), [&](InstId const instId, SSACFG::Inst const& inst) {

    if (

      InstId const phi = _cfg.upsilonPhi(instId);

      _cfg.inst(phi).block == _to

    )

      m_phiToPreImage[phi] = inst.inputs.at(0);

  });

}

bool PhiInverse::noOp() const

{

  return m_phiToPreImage.empty();

}

InstId PhiInverse::operator()(InstId _valueId) const

{

  return solidity::util::valueOrDefault(m_phiToPreImage, _valueId, _valueId);

}

std::map<InstId, InstId> const& PhiInverse::data() const

{

  return m_phiToPreImage;

}