https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64331
--- Comment #5 from Eric Botcazou <ebotcazou at gcc dot gnu.org> --- > Is it just REG_USED/REG_DEAD notes, or is register liveliness > (df_regs_ever_live_p etc..) also not guaranteed to be up to date? These REG_UNUSED/REG_DEAD notes are special because they are not maintained incrementally by the DF framework, i.e. the insn manipulation routines don't cause them to be updated, so they are really valid only just after they are recomputed. The rest of the liveness info is updated incrementally (if DF is asked to).
