[Mesa-dev] [PATCH 10/12] i965/fs: Make compact_virtual_grfs an optimization pass

[Matt Turner]

On Fri, Sep 19, 2014 at 5:41 PM, Matt Turner <mattst88 at gmail.com> wrote:
> On Fri, Sep 19, 2014 at 1:10 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
>> Previously we disabled compact_virtual_grfs when dumping optimizations.
>> The idea here was to make it easier to diff the dumped shader because you
>> didn't have a sudden renaming.  However, sometimes a bug is affected by
>> compact_virtual_grfs and, when this happens, you want to keep dumping
>> instructions with compact_virtual_grfs enabled.  By turning it into an
>> optimization pass and dumping it along with the others, we retain the
>> ability to diff because you can just diff against the compact_virtual_grf
>> output.
>
> I'd like to understand the bug you encountered.
>
> I'm kind of concerned that we're going to just run the optimization
> loop an extra time for every shader now, since compact_virtual_grfs is
> going to set progress = true after the last actual optimization pass
> made progress. I guess we could remove that problem by calling
> compact_virtual_grfs at the end of the loop, rather than at the
> beginning.

Assuming it works and doesn't increase the number of loop iterations,
just moving the compact_virtual_grfs() to the end of the optimization
loop, this would be

Reviewed-by: Matt Turner <mattst88 at gmail.com>