[Mesa-dev] [PATCH mesa v2 3/3] nouveau: codegen: LOAD: Take src swizzle into account

[Marek Olšák]

On Fri, Apr 22, 2016 at 9:23 AM, Hans de Goede <hdegoede at redhat.com> wrote:
> Hi,
>
> On 22-04-16 09:08, Marek Olšák wrote:
>>
>> On Thu, Apr 21, 2016 at 7:04 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>>>
>>> [+radeon folk]
>>>
>>> Marek, Nicolai, Bas - please have a look at the doc change and let us
>>> know if you think this will cause a problem for radeon.
>>>
>>> Hans is solving the issue that he wants to swizzle the data loaded
>>> from the image/buffer/whatever before sticking it into the dst
>>> register.
>>
>>
>> Is this something st/mesa needs or just nouveau? If just nouveau needs
>> it, I don't see a point in updating the TGSI spec, since nouveau can
>> just add the swizzle when translating from TGSI.
>
>
> This is something which the llvm tgsi backend needs, which we plan to
> use to add opencl support to nouveau.
>
> From the commit msg:
>
> "The llvm TGSI backend uses pointers in registers and does things like:
>
> LOAD TEMP[0].y, MEMORY[0], TEMP[0]
>
> Expecting the data at address TEMP[0].x to get loaded to
> TEMP[0].y. But this will cause the data at TEMP[0].x + 4 to be
> loaded instead.
>
> This commit adds support for a swizzle suffix for the 1st source
> operand, which allows using:
>
> LOAD TEMP[0].y, MEMORY[0].xxxx, TEMP[0]
>
> And actually getting the desired behavior"

If radeonsi needs no changes and st/mesa doesn't change behavior, it's OK.

Marek