...
class Simplification

operation exclusive-or

else if (IsConstEqual(x, AllOnes(operation.Destination.Type)))
{
        operation.TurnInto(
                Instruction.BitwiseNot,
                y
        );
        return true;
}

...
class Operation

public void TurnInto(Instruction instruction, Operand destination, [NotNull] params Operand[] sources)
{
        Instruction = instruction;

        if (Destination != destination)
        {
                SetDestination(destination);
        }

        SetSources(sources);
}