/// <summary>
/// Check if "condition ? trueInst : falseInst" can be simplified using the null-conditional operator.
/// Returns the replacement instruction, or null if no replacement is possible.
/// </summary>
internal ILInstruction Run(ILInstruction condition, ILInstruction trueInst, ILInstruction falseInst)
{
Debug.Assert(context.Settings.NullPropagation);
Debug.Assert(!condition.MatchLogicNot(out _), "Caller should pass in positive condition");
if (condition is Comp comp && comp.Left.MatchLdLoc(out var testedVar) && comp.Right.MatchLdNull())
{
if (comp.LiftingKind != ComparisonLiftingKind.None)
{
return(null);
}
if (comp.Kind == ComparisonKind.Equality)
{
// testedVar == null ? trueInst : falseInst
return(TryNullPropagation(testedVar, falseInst, trueInst, Mode.ReferenceType));
}
else if (comp.Kind == ComparisonKind.Inequality)
{
return(TryNullPropagation(testedVar, trueInst, falseInst, Mode.ReferenceType));
}
}