[Mesa-dev] [PATCH 1/2] gallium: add TGSI_OPCODE_FMA

[Ilia Mirkin]

On Mon, Mar 2, 2015 at 3:16 PM, Roland Scheidegger <sroland at vmware.com> wrote:
> Am 02.03.2015 um 20:50 schrieb Ilia Mirkin:
>> On Mon, Mar 2, 2015 at 2:44 PM, Marek Olšák <maraeo at gmail.com>
>> wrote:
>>> On Mon, Mar 2, 2015 at 5:09 PM, Ilia Mirkin <imirkin at alum.mit.edu>
>>> wrote:
>>>> Like Roland mentioned, you need to add DFMA, and the relevant
>>>> cases to glsl_to_tgsi_visitor::get_opcode so that it can be
>>>> selected.
>>>
>>> I plan to add DFMA too, but it's really low priority for me right
>>> now.
>>
>> OK, well, without DFMA, I'm fairly sure that this will break fp64 if
>> you add support for the opcode in softpipe (or I add it in nvc0).
> I guess if double fmas there happen when translating to tgsi you could
> always translate them to dmad still.

Yeah, I just meant the more immediate situation that st_glsl_to_tgsi
will fail because it will try to use FMA for double values. You could
just as well add a thing to get_opcode() which selects DMAD as the
double alternate to FMA.