http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56921
--- Comment #9 from rguenther at suse dot de <rguenther at suse dot de> 2013-04-12 08:45:46 UTC --- On Fri, 12 Apr 2013, steven at gcc dot gnu.org wrote: > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56921 > > --- Comment #8 from Steven Bosscher <steven at gcc dot gnu.org> 2013-04-12 > 08:36:04 UTC --- > (In reply to comment #7) > > niter_desc is not marked GTY(()) but is cached from struct loop aux field. > > niter_desc uses heap memory but points to GC memory. Thus, caching of this > > across passes is not safe. > > I suppose passes are missing free_simple_loop_desc, loop-doloop.c calls > > get_simple_loop_desc but never free_simple_loop_desc for example (which > > then at least leaks the niter_desc memory). > > Another, IMHO better, solution would be to not use loop->aux but make > a GC-safe vec indexed by loop->num. Maybe add checking in the loop > verifier that no struct niter_desc is left pending if its parent loop > is removed. > > That should make the loop passes GC safe. > > Then mark all "aux" fields as GC unsafe and document that every pass is > responsible for cleaning up after itself. Yes, definitely. I was bit once by this ->aux usage which is not really obvious. Richard.
