https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92283
--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Richard Biener from comment #12) > Trying to bisect with IVOPTs debug-counter. > > 65:69 FAIL > 65:66 OK > 67:69 OK > > *sigh* Back to this (ivopts_loop counter soon to be checked in). 66:68 FAIL 66:67 FAIL (66:66 OK 67:67 OK) interestingly 66:66 and 67:67 generate exactly the same code and 66:67 add a single loop. That's totally odd but probably an artifact of a bug in dbg_cnt_is_enabled which does bool dbg_cnt_is_enabled (enum debug_counter index) { unsigned v = count[index]; return v > limit_low[index] && v <= limit_high[index]; } where it should be v >= limit_low[index]. It's also nowhere documented but zero is a value never in the set of tested values. So it points to a single loops IVOPTs optimization.