microblaze unroll loops optimization

[Michael Eager]

On 01/11/2013 06:53 PM, David Holsgrove wrote:
> Hi all,
>
> I believe the decision to use UNSPEC_CMP and UNSPEC_CMPU for microblaze
> compare instructions stems from the conversation in this thread from 2009;
>
> http://gcc.gnu.org/ml/gcc/2009-12/msg00283.html

Thanks for reminding me.  I'd forgotten that Paolo suggested using UNSPEC.

I still think it's a bit odd.  Other targets use the comparison
operator (e.g., lt, ge, etc.).  Microblaze should as well.

> This makes sense, because if I use code attributes and iterators to extend the
> compare insn as so;
>
> (define_code_iterator any_cmp [gt ge lt le gtu geu ltu leu])

Using UNSPEC and code interators should be unrelated.

-- 
Michael Eager	 eager@eagercon.com
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