https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80460
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> --- I thought we could (in collect_fallthrough_labels) look at the GIMPLE_COND, see if its OP0 and OP1 are INTEGER_CSTs, and if they are, determine which branch cannot be taken, and then maybe don't do labels->safe_push (l); which should suppress the warning.
