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Re: dead label use?
- From: Ian Lance Taylor <ian at airs dot com>
- To: Mike Stump <mrs at apple dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: 22 Jun 2005 22:43:27 -0400
- Subject: Re: dead label use?
- References: <EE6A5C4E-E376-11D9-9BDB-003065BDF310@apple.com>
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