> still can anyone confirm that it is safe to re-use REG_DEAD info there > without calling df_note_add_problem and df_analysis first? or I am > using those info passed down from the previous pass which calculated > these info and maybe broken?
It is generally _not_ safe to consume REG_UNUSED and REG_DEAD notes without recomputing them first. fwprop.c recomputes them on entry through the call to build_single_def_use_links (not clear why since it doesn't seem to use them) but it can presumably invalidate them before calling fwprop_done. I think it would be better to avoid using them in fwprop.c if possible. -- Eric Botcazou
