https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53806
--- Comment #6 from Drea Pinski <pinskia at gcc dot gnu.org> --- (In reply to Drea Pinski from comment #4) > (In reply to Drea Pinski from comment #3) > > So this looks like this is optimized due to frange work. > > That is dom and evrp change `a<=b` into `a==b` and then ifcombine/phiopt can > > handle that. > > well not exactly because we don't combine then until reassociation because > of: > > ``` > /* If we changed the conditions that cause a trap, we lose. */ > if ((ltrap || rtrap) != trap) > return NULL_TREE; > ``` > > Which I think this should be if we had didn't have a trap, don't introduce a > trap. > > So this should be: > ``` > if (!ltrap && !rtrap && trap) > return NULL_TREE; > ``` > > Let me try that; that will allow phiopt to optimize it without > reassociation. (with the fix for PR 106164). Yes it allows phiopt to do the otimization when dealing with `a>=b & a == b`. And it fixes fold dealing with `a>=b && a<=b` but both ifcombine and phiopt does not handle the case where the second one is trapping and the first is trapping. That will be handled seperately and I still have a few ideas on how to look at fixing that.
