     '[
         instructions>>
         [ pop* ] [ pop ] [ ] tri
+        [ [ \ ##safepoint new-insn ] dip push ]
         [ [ \ ##epilogue new-insn ] dip push ]
-        [ _ dip push ] bi
+        [ _ dip push ] tri
     ]
     [ successors>> delete-all ]
     bi ; inline


: convert-loop-tail-call ( bb -- )
    ! If a word calls itself, this becomes a loop in the CFG.
    [ instructions>> [ pop* ] [ pop* ] [ [ \ ##branch new-insn ] dip push ] tri ]
    [ successors>> delete-all ]
    [ [ cfg get entry>> successors>> first ] dip successors>> push ]
    tri ;

: return? ( bb -- ? )
    skip-empty-blocks
    instructions>> {
        [ length 3 = ]
        [ first ##safepoint? ]
        [ second ##epilogue? ]
        [ third ##return? ]

        ! [ length 2 = ]
        ! [ first ##epilogue? ]
        ! [ second ##return? ]
    } 1&& ;

: tail-call? ( bb -- ? )
