[Bug tree-optimization/125399] Missed optimization of __builtin_bitreverse8() when comparing to 0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125399

Drea Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2026-05-21
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
            Summary|Missed optimization of      |Missed optimization of
                   |__builtin_bitreverse*()     |__builtin_bitreverse8()
                   |when comparing to 0         |when comparing to 0

--- Comment #3 from Drea Pinski <pinskia at gcc dot gnu.org> ---
Oh the problem is just with 8.
BITREVERSE missed 8:

(define_operator_list BITREVERSE BUILT_IN_BITREVERSE16 BUILT_IN_BITREVERSE32
            BUILT_IN_BITREVERSE64 BUILT_IN_BITREVERSE128)

So that is an easy fix.