Re: [Mesa3d-dev] GSOC: Gallium R300 driver

[Corbin S. <mos...@gm...>]

On Tue, Mar 30, 2010 at 8:37 AM, Luca Barbieri <luc...@gm...> wrote:
>> Another idea was to convert TGSI to a SSA form. That would make unrolling
>> branches much easier as the Phi function would basically become a linear
>> interpolation, loops and subroutines with conditional return statements
>> might be trickier. The r300 compiler already uses SSA for its optimization
>> passes so maybe you wouldn't need to mess with TGSI that much...
>>
>>>
>>> Is the conditional translation something that only needs to be done
>>> in the Gallium drivers, or would it be useful to apply the translation
>>> before the Mesa IR is converted into TGSI?  Are any of the other drivers
>>> (Gallium or Mesa) currently doing this kind of translation?
>>
>> Not that I know of. You may do it wherever you want theoretically, even in
>> the r300 compiler and leaving TGSI untouched, but I think most people would
>> appreciate if these translation were done in TGSI.
>
> It would be nice to have a driver-independent TGSI optimization module.
> It could either operate directly on TGSI (probably only good for
> simple optimization), or convert to LLVM IR, optimize, and convert
> back.
>
> This would allow to use this for all drivers: note that at least
> inlining and loop unrolling should generally be performed even for
> hardware with full control flow support.
> Lots of other optimizations would then be possible (using LLVM, with a
> single line of code to request the appropriate LLVM pass), and would
> automatically be available for all drivers, instead of being only
> available for r300 by putting them in the radeon compiler.

This is orthogonal to the suggested project...

-- 
When the facts change, I change my mind. What do you do, sir? ~ Keynes

Corbin Simpson
<Mos...@gm...>