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Re: How to fill delay slot for a VLIW target?
- From: Jim Wilson <wilson at tuliptree dot org>
- To: Jeff Chen <jeffchen at magima dot com dot cn>
- Cc: gcc at gcc dot gnu dot org
- Date: Wed, 11 Jun 2003 12:48:38 -0700
- Subject: Re: How to fill delay slot for a VLIW target?
- References: <3EE6F9DE.8040804@magima.com.cn>
Jeff Chen wrote:
it seems that GCC schedules delay slot on the basis of insn, not on VLIW
bundle, so is it possible to use define_delay for such a VLIW target?
I think you will have problems getting this to work the way you want it
to, unless you spend time rewriting parts of reorg.c. define_delay can
handle multiple instructions in a very limited way, but there is no
support for variable number of instructions.
Another option is writing your own target dependent pass using
machine_dependent_reorg. We try to discourage people from trying to
write machine dependent passes, but for a case like this, it might be
reasonable.
Jim