dead label use?

[Ian Lance Taylor]

Mike Stump <mrs@apple.com> writes:

> 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")])

This is an instantiation of a tablejump created via define_expand.
Operand 1 is the jump table.  The insn needs to refer to it, or the
table will be deleted as unreferenced.

Ian