A function with an unlikely slowpath can easily end up arranged as

    top part
    jxx slow
    fast middle part
  end:
    bottom part
    ret
  slow:
    slow middle part
    jmp end

There may be more than one slow part, the slow parts might actually be exiled from inside a loop and not a simple linear code path and can themselves contain loops, etc. Play with __builtin_expect and objdump --visualize-jumps a bit and you’ll encounter many variations.