[Mesa-dev] [PATCH v2 1/3] i965: add FS_OPCODE_OVERWRITE_DST

[Chia-I Wu]

On Wed, Oct 16, 2013 at 6:26 AM, Eric Anholt <eric at anholt.net> wrote:
> Chia-I Wu <olvaffe at gmail.com> writes:
>
>> From: Chia-I Wu <olv at lunarg.com>
>>
>> FS_OPCODE_OVERWRITE_DST is used to indicate that the destination register is
>> (completely) overwritten.  No code is emitted, but the liveness analysis can
>> use it as a hint to add the destination register to DEF bitset.  This is
>> needed because it is hard to figure out if some partial writes combined
>> constitute a complete write during liveness analysis, while it is easier for
>> the FS visitor to know if that is the case.
>
> Note that FS_OPCODE_OVERWRITE_DST should be avoidable now that
> texture-grf is landed -- the live intervals calculation is a lot
> smarter, and shouldn't take much more work to handle the setup of the
> two halves in 16-wide.
Thanks for the hint!

I've posted v3 for review.  FS_OPCODE_OVERWRITE_DST is gone, and the
payloads for dual sample_d are constructed directly in GRF.

-- 
olv at LunarG.com