https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78016
--- Comment #3 from Eric Botcazou <ebotcazou at gcc dot gnu.org> --- > I am wondering whether it's OK to use copy_insn_1 here? that is to replace > the whole for loop into something simply as "REG_NOTES (new_insn) = > copy_insn_1 (REG_NOTES (old_insn);" as I think copy_insn_1 will do > recursive copy. This is what's used in old reload1.c. Yet another way of copying notes... I didn't know about it but, yes, it looks well-behaved, albeit a bit heavier than the others. Ideally we would have a single routine along the other routines in rtlanal.c to deal with note copying, with a few boolean parameters to drop some of them. > So copy_insn_1 is safe? I'd write something more specialized in rtlanal.c instead. > For the other two places, try_split will just return if the insn is > RTX_FRAME_RELATED_P, so should be OK. > > /* We're not good at redistributing frame information. */ > if (RTX_FRAME_RELATED_P (trial)) > return trial; Yes, maybe try_split can be set aside because it's more of note distribution than of note copying. > While for create_copy_of_insn_rtx in sel-sched-ir.c, I find those historical > discussion at https://gcc.gnu.org/ml/gcc-patches/2011-12/msg01232.html, it > was supposed to copy REG_ARGS_SIZE only, later extended to all except > REG_LABEL_OPERAND/REG_EQUAL/REG_EQUALV. There is actually no > mark_jump_label here, so I am thinking the skip of REG_LABEL_OPERAND is > wrong, while I am not sure if copying REG_EQUAL/REG_EQUALV is wrong. It's probably a pasto + a sneaky way of dropping REG_EQUAL/REG_EQUAL notes that have been made invalid by some transformation.
