https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122663
--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Richard Biener from comment #7) > this shows that the way to discover the "unused leaf" does not handle cycles > properly, as would simple_dce_from_worklist. We have > > m_9 = _7 | m_8; > ... > # m_8 = PHI <2(4), m_9(5)> > > here. yes simple_dce_from_worklist only handles the simpliest cycle case (the ssa name used in its own phi definition which was added with r14-712-g3e8f8ab5237002). Expanding it to handle the one statement case might be fast enough still (I wonder if this is now missed in ccp1 after r14-569-g21e2ef2dc25de3; I didn't see it at the time though).
