dead label use?

[Mike Stump]

Forgive me ignorance, is there is use for the use of the label below?
From rs6000, though, certainly there are other examples of this sort of 
thing in the md files:

(define_insn ""
  [(set (pc)
        (match_operand:P 0 "register_operand" "c,*l"))
   (use (label_ref (match_operand 1 "" "")))]
  ""
  "@
   bctr
   {br|blr}"
  [(set_attr "type" "jmpreg")])