https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98226
--- Comment #11 from Oleg Zaikin <zaikin.icc at gmail dot com> --- (In reply to Jonathan Wakely from comment #8) > That needs to be investigated, but it's a problem with the compiler. It has > nothing to do with countr_one being implemented using countr_zero (as shown > by the same problem being present when calling __builtin_ctz directly). Thank you for the detailed clarification!