https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126721
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> Confirmed. For constants should be constant folding, for uniform
> non-constant values general folding.
>
> There's also like nonzero bits and uniform-in-the-"range" values. Aka even
> extracts from { 0, 1, 0, 1, 0, 1 ... } or [2,5] extract from { a, b, c, c,
> c, d, e }.
That said, the uniformity check could work on a subrange/bitmask, it needs
to iterate over all elements anyway.
