[IshKebab]

As far as I understand it there's no need for that. You don't need to say [0, 256) except 0; you can just say [1, 256).

[Lvl999Noob]

With subtraction, you can say [0, 256) except [4, 9, 15, 26]. You can do that just by narrowing a single range.

But then, its kinda hard to optimise such a split range in the general case. The narrowing option gives you 80% (maybe more) of the performance at 20% (probably even less) of the cost.