protected override ISet <DescriptorKind> Transfer(SubtractExpression expression, RuleEngine engine)
{
var left = engine.Visit(expression.Left);
var right = engine.Visit(expression.Right);
if (right.Contains(Zero.Instance))
{
return(left);
}
var result = new HashSet <DescriptorKind>();
if (_IsLoopDependent(left, right))
{
result.Add(LoopDependent.Instance);
}
if (left.Contains(Positive.Instance) && right.Contains(Negative.Instance))
{
result.Add(Positive.Instance);
result.Add(NotZero.Instance);
}
else if (left.Contains(Negative.Instance) && right.Contains(Positive.Instance))
{
result.Add(Negative.Instance);
result.Add(NotZero.Instance);
}
if (AllContainRule(LoopIndependent.Instance, left, right))
{
result.Add(LoopIndependent.Instance);
}
return(result);
}
protected override ISet <DescriptorKind> Transfer(DivideExpression expression, RuleEngine engine)
{
var left = engine.Visit(expression.Left);
var right = engine.Visit(expression.Right);
if (right.Contains(One.Instance) || left.Contains(Zero.Instance))
{
return(left);
}
if (AllContainRule(LoopIndependent.Instance, left, right))
{
return(_loopIndependentSet);
}
return(_emptySet);
}
protected override ISet <DescriptorKind> Transfer(ModuloExpression expression, RuleEngine engine)
{
var left = engine.Visit(expression.Left);
var right = engine.Visit(expression.Right);
var result = new HashSet <DescriptorKind>();
if (left.Contains(Zero.Instance) || right.Contains(One.Instance))
{
result.Add(Zero.Instance);
}
if (AllContainRule(LoopIndependent.Instance, left, right))
{
result.Add(LoopIndependent.Instance);
}
return(result);
}
protected override ISet <DescriptorKind> Transfer(UnaryMinusExpression expression, RuleEngine engine)
{
var result = new HashSet <DescriptorKind>(engine.Visit(expression.Expression));
if (result.Contains(Positive.Instance))
{
result.Remove(Positive.Instance);
result.Add(Negative.Instance);
}
else if (result.Contains(Negative.Instance))
{
result.Remove(Negative.Instance);
result.Add(Positive.Instance);
}
return(result);
}