[Mesa-dev] [PATCH 2/3] st: Sweep NIR after linking phase to free held memory

[Timothy Arceri]

On 19/07/18 08:31, Eric Anholt wrote:
> Danylo Piliaiev <danylo.piliaiev at gmail.com> writes:
> 
>> After optimization passes and many trasfromations most of memory
> 
> "transformations"
> 
>> NIR holds is a garbage which was being freed only after shader deletion.
> 
> "is garbage"
> 
>> Freeing it at the end of linking will save memory which would be useful
>> in case there are a lot of complex shaders being compiled.
>> The common case for this issue is 32bit game running under Wine.
>>
>> The cost of the optimization is around ~3-5% of compilation speed
>> with complex shaders.
>>
>> Signed-off-by: Danylo Piliaiev <danylo.piliaiev at globallogic.com>
> 
> This seems good, and I'm running it through the CTS now.
> 

The problem is this does the sweep too early. We still do lots of work 
on NIR after this, I've thought about this a few times and it really 
seems we should be able to call a driver specific function from the st 
and pass it the IR so it can do what ever it wants (lowering opts etc) 
and spits it back out. Once this is done we should then call sweep and 
cache the IR.

At the very least we should call sweep before we cache NIR rather than 
where this patch places it.