[Bug middle-end/106727] Missed fold / canonicalization for checking if a number is a power of 2

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106727

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-08-24

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  Expanding __builtin_popcount (n) <= 1 as (n & (n - 1)) == 0 might
be already done.  The canonicalization could be applied if .POPCOUNT is
available.