https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90836
--- Comment #2 from Wilco <wilco at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> While it could be matched in match.pd variations would be quite a lot.
> I don't see where else it fits (apart from forwprop which already does
> fancy pattern matching...).
>
> You probably want to match generic INTEGER_CSTs and delay the actual
> verification into a with {}.
>
> I suppose popcount on integers other than long long work with the same
> pattern?
There are lots of possible variations and given proving that a particular
sequence is equivalent to popcount may be too difficult, it's about supporting
the cases that occur in code that people care about.
