https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108738
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> --- The odd thing is that DF_REF_CHAIN of a USE ref contains _all_ definitions of the pseudo while DF_REF_CHAIN of a DEF ref contains only reaching uses!? Probably an artifact of how df_chain_create_bb_process_use operates. That makes this much harder to fix ...
