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Support unassigned variables in the SSA value tracker and the data flow analyzer.

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chriseth
2018-12-12 18:06:28 +01:00
parent 5e0c312dad
commit 9557dd7e74
10 changed files with 65 additions and 13 deletions
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libyul/optimiser/DataFlowAnalyzer.cpp
+7 -2
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@@ -136,17 +136,22 @@ void DataFlowAnalyzer::operator()(Block& _block)
void DataFlowAnalyzer::handleAssignment(set<YulString> const& _variables, Expression* _value)
{
static Expression const zero{Literal{{}, LiteralKind::Number, YulString{"0"}, {}}};
clearValues(_variables);
MovableChecker movableChecker;
if (_value)
movableChecker.visit(*_value);
if (_variables.size() == 1)
else
for (auto const& var: _variables)
m_value[var] = &zero;
if (_value && _variables.size() == 1)
{
YulString name = *_variables.begin();
// Expression has to be movable and cannot contain a reference
// to the variable that will be assigned to.
if (_value && movableChecker.movable() && !movableChecker.referencedVariables().count(name))
if (movableChecker.movable() && !movableChecker.referencedVariables().count(name))
m_value[name] = _value;
}