UNION: irrelevant ##peek ##replace ##inc ;
-: split-instructions? ( insns -- ? ) [ irrelevant? not ] count-by 5 <= ;
+: split-instructions? ( insns -- ? ) [ irrelevant? not ] count 5 <= ;
: short-tail-block? ( bb -- ? )
{ [ successors>> empty? ] [ instructions>> length 2 = ] } 1&& ;