https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116460
--- Comment #16 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Richard Biener from comment #14) > (In reply to Andrew Pinski from comment #13) > > (In reply to Andrew Pinski from comment #8) > > > ./a.ltrans6.ltrans.212t.forwprop4 > > > > > > Removing dead stmt noDataCandVec$_M_start_888 = PHI <_1783(176), > > > _577(186)> > > > ... > > > Removing dead stmt:_598 = _888 + 16; > > > > > > So it looks like we remove the statement defining _888 and then removing > > > the > > > use. > > > The removal of _888 happens directly from forwprop while _598 definition > > > removal comes from simple_dce_from_worklist . > > > > > > The ICE happens because the ssa name _888 has already been freed so the > > > type > > > is null (and not in this case a pointer) since this was originally a > > > pointer > > > plus. > > > > > > Trying to reduce this further. > > > > _888 definition is from a BB which is going to be removed so we should not > > need to mark its uses as being needed for dce worklist. But I am not sure > > how to detect that case. > > forwprop shouldn't remove _888 if there's a use left. When adding > simple_dce_from_worklist, did you remove some manual stmt removal > (adding to to_remove)? Having both is a bit ugly (see also > remove_prop_source_from_use), but the sets need to be separate to > avoid interactions like this. Richard, you are the one who added simple_dce_from_worklist to forwprop in the end; I had tried originally by not do the manual one but ran into regressions so I didn't submit it.
