https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108463
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Note, we already distinguish between n_useless_values and
n_useless_debug_values:
if (had_locs && cselib_useless_value_p (v))
{
if (setting_insn && DEBUG_INSN_P (setting_insn))
n_useless_debug_values++;
else
n_useless_values++;
values_became_useless = 1;
}
so the important thing is find out which value created only in the -g case
didn't get marked with setting_insn && DEBUG_INSN_P (setting_insn).