solidity/libyul/optimiser/ForLoopConditionOutOfBody.cpp
2019-11-19 17:23:18 +01:00

75 lines
2.3 KiB
C++

/*
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/>.
*/
#include <libyul/optimiser/ForLoopConditionOutOfBody.h>
#include <libyul/optimiser/Semantics.h>
#include <libyul/AsmData.h>
#include <libyul/Utilities.h>
#include <libdevcore/CommonData.h>
using namespace std;
using namespace dev;
using namespace yul;
void ForLoopConditionOutOfBody::run(OptimiserStepContext& _context, Block& _ast)
{
ForLoopConditionOutOfBody{_context.dialect}(_ast);
}
void ForLoopConditionOutOfBody::operator()(ForLoop& _forLoop)
{
ASTModifier::operator()(_forLoop);
if (
!m_dialect.booleanNegationFunction() ||
!holds_alternative<Literal>(*_forLoop.condition) ||
valueOfLiteral(std::get<Literal>(*_forLoop.condition)) == u256(0) ||
_forLoop.body.statements.empty() ||
!holds_alternative<If>(_forLoop.body.statements.front())
)
return;
If& firstStatement = std::get<If>(_forLoop.body.statements.front());
if (
firstStatement.body.statements.empty() ||
!holds_alternative<Break>(firstStatement.body.statements.front())
)
return;
if (!SideEffectsCollector(m_dialect, *firstStatement.condition).movable())
return;
YulString iszero = m_dialect.booleanNegationFunction()->name;
langutil::SourceLocation location = locationOf(*firstStatement.condition);
if (
holds_alternative<FunctionCall>(*firstStatement.condition) &&
std::get<FunctionCall>(*firstStatement.condition).functionName.name == iszero
)
_forLoop.condition = make_unique<Expression>(std::move(std::get<FunctionCall>(*firstStatement.condition).arguments.front()));
else
_forLoop.condition = make_unique<Expression>(FunctionCall{
location,
Identifier{location, iszero},
make_vector<Expression>(
std::move(*firstStatement.condition)
)
});
_forLoop.body.statements.erase(_forLoop.body.statements.begin());
}