[Mesa-dev] [PATCH 06/16] nir: improve convert_yuv_to_rgb when fuse_ffma=true

[Jonathan Marek]

There's no updated series yet. This patch will work on its own and the 
issue that was pointed out doesn't affect behavior at all.

On 1/7/19 4:47 PM, Lionel Landwerlin wrote:
> I did not but then saw someone pointed out an issue with this particular 
> patch.
> I can do tomorrow.
> Do you have link to the updated series?
> 
> Thanks,
> 
> -
> Lionel
> 
> On 07/01/2019 16:54, Jonathan Marek wrote:
>> Hi,
>>
>> Did you get a chance try this? If not, I might be able to try it 
>> myself as I have Intel HW.
>>
>> On 12/19/18 12:34 PM, Lionel Landwerlin wrote:
>>> Hey Jonathan,
>>>
>>> I'm kind of curious as to whether we can have a single expression 
>>> that pretty much generates the same final code (through some of the 
>>> algebraic lowering/optimizations).
>>> I'll give it a try on Intel HW, see what it does.
>>>
>>> -
>>> Lionel
>>>
>>> On 19/12/2018 16:39, Jonathan Marek wrote:
>>>> When ffma is available, we can use a different arrangement of 
>>>> constants to
>>>> get a better result. On freedreno/ir3, this reduces the YUV->RGB to 7
>>>> scalar ffma. On freedreno/a2xx, it will allow YUV->RGB to be 3 vec4 
>>>> ffma.
>>>>
>>>> Signed-off-by: Jonathan Marek <jonathan at marek.ca>
>>>> ---
>>>>   src/compiler/nir/nir_lower_tex.c | 62 
>>>> ++++++++++++++++++++++----------
>>>>   1 file changed, 43 insertions(+), 19 deletions(-)
>>>>
>>>> diff --git a/src/compiler/nir/nir_lower_tex.c 
>>>> b/src/compiler/nir/nir_lower_tex.c
>>>> index 6a6b6c41a7..f7c821bb34 100644
>>>> --- a/src/compiler/nir/nir_lower_tex.c
>>>> +++ b/src/compiler/nir/nir_lower_tex.c
>>>> @@ -342,25 +342,49 @@ convert_yuv_to_rgb(nir_builder *b, 
>>>> nir_tex_instr *tex,
>>>>                      nir_ssa_def *y, nir_ssa_def *u, nir_ssa_def *v,
>>>>                      nir_ssa_def *a)
>>>>   {
>>>> -   nir_const_value m[3] = {
>>>> -      { .f32 = { 1.0f,  0.0f,         1.59602678f, 0.0f } },
>>>> -      { .f32 = { 1.0f, -0.39176229f, -0.81296764f, 0.0f } },
>>>> -      { .f32 = { 1.0f,  2.01723214f,  0.0f,        0.0f } }
>>>> -   };
>>>> -
>>>> -   nir_ssa_def *yuv =
>>>> -      nir_vec4(b,
>>>> -               nir_fmul(b, nir_imm_float(b, 1.16438356f),
>>>> -                        nir_fadd(b, y, nir_imm_float(b, -16.0f / 
>>>> 255.0f))),
>>>> -               nir_channel(b, nir_fadd(b, u, nir_imm_float(b, 
>>>> -128.0f / 255.0f)), 0),
>>>> -               nir_channel(b, nir_fadd(b, v, nir_imm_float(b, 
>>>> -128.0f / 255.0f)), 0),
>>>> -               nir_imm_float(b, 0.0));
>>>> -
>>>> -   nir_ssa_def *red = nir_fdot4(b, yuv, nir_build_imm(b, 4, 32, 
>>>> m[0]));
>>>> -   nir_ssa_def *green = nir_fdot4(b, yuv, nir_build_imm(b, 4, 32, 
>>>> m[1]));
>>>> -   nir_ssa_def *blue = nir_fdot4(b, yuv, nir_build_imm(b, 4, 32, 
>>>> m[2]));
>>>> -
>>>> -   nir_ssa_def *result = nir_vec4(b, red, green, blue, a);
>>>> +   nir_ssa_def *result;
>>>> +
>>>> +
>>>> +   if (b->shader->options->fuse_ffma) {
>>>> +      nir_const_value m[4] = {
>>>> +         { .f32 = { 1.16438356f, 1.16438356f, 1.16438356f, 0.0f } },
>>>> +         { .f32 = { 0.0f,       -0.39176229f, 2.01723214f, 0.0f } },
>>>> +         { .f32 = { 1.59602678f,-0.81296764f, 0.0f, 0.0f } },
>>>> +      };
>>>> +      static const float y_off = -16.0f * 1.16438356f / 255.0f;
>>>> +      static const float sc = 128.0f / 255.0f;
>>>> +
>>>> +      nir_ssa_def *offset =
>>>> +         nir_vec4(b,
>>>> +                  nir_imm_float(b, y_off - sc * 1.59602678f),
>>>> +                  nir_imm_float(b, y_off + sc * (0.81296764f + 
>>>> 0.39176229f)),
>>>> +                  nir_imm_float(b, y_off - sc * 2.01723214f),
>>>> +                  a);
>>>> +
>>>> +      result = nir_ffma(b, y, nir_build_imm(b, 4, 32, m[0]),
>>>> +                       nir_ffma(b, u, nir_build_imm(b, 4, 32, m[1]),
>>>> +                                nir_ffma(b, v, nir_build_imm(b, 4, 
>>>> 32, m[2]), offset)));
>>>> +   } else {
>>>> +      nir_const_value m[3] = {
>>>> +         { .f32 = { 1.0f,  0.0f,         1.59602678f, 0.0f } },
>>>> +         { .f32 = { 1.0f, -0.39176229f, -0.81296764f, 0.0f } },
>>>> +         { .f32 = { 1.0f,  2.01723214f,  0.0f,        0.0f } }
>>>> +      };
>>>> +
>>>> +      nir_ssa_def *yuv =
>>>> +         nir_vec4(b,
>>>> +                  nir_fmul(b, nir_imm_float(b, 1.16438356f),
>>>> +                           nir_fadd(b, y, nir_imm_float(b, -16.0f / 
>>>> 255.0f))),
>>>> +                  nir_channel(b, nir_fadd(b, u, nir_imm_float(b, 
>>>> -128.0f / 255.0f)), 0),
>>>> +                  nir_channel(b, nir_fadd(b, v, nir_imm_float(b, 
>>>> -128.0f / 255.0f)), 0),
>>>> +                  nir_imm_float(b, 0.0));
>>>> +
>>>> +      nir_ssa_def *red = nir_fdot4(b, yuv, nir_build_imm(b, 4, 32, 
>>>> m[0]));
>>>> +      nir_ssa_def *green = nir_fdot4(b, yuv, nir_build_imm(b, 4, 
>>>> 32, m[1]));
>>>> +      nir_ssa_def *blue = nir_fdot4(b, yuv, nir_build_imm(b, 4, 32, 
>>>> m[2]));
>>>> +
>>>> +      result = nir_vec4(b, red, green, blue, a);
>>>> +   }
>>>>      nir_ssa_def_rewrite_uses(&tex->dest.ssa, nir_src_for_ssa(result));
>>>>   }
>>>
>>>
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> 
>