https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94779
--- Comment #16 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #15)
> (In reply to Martin Liška from comment #14)
> > Ok, I've just taken look at what EVRP pass does before SWITCHCONV pass is
> > called.
> > I see that EVRP can properly prune dead cases of a switch, but it's not
> > perfect:
> >
> > int f1(unsigned x)
> > {
> > if (x == 2 || x == 3 || x >= 5)
> > __builtin_unreachable ();
> > switch (x)
> > {
> > case 0: return 1;
> > case 1: return 2;
> > case 2: return 3;
> > case 3 ... 8: return 4;
> > }
> > }
>
> The old VRP/EVRP only tracks simple ranges and anti-ranges, so can't deal
> with
> what you have above, the new ranger code can deal with multiple subranges,
> but the question is if all the interfaces deal with those.
EVRP knows the proper range:
2->4 (F) x_6(D) : unsigned int [0, 1][4, 4]
>
> > This seems to me like a strange EVRP transformation :/
>
> Why? And, the user could have written it that way too.
Looking into it.
