[Mesa-dev] [PATCH] radv: export SampleMask from pixel shaders at full rate

Samuel Pitoiset samuel.pitoiset at gmail.com
Thu Dec 14 11:52:59 UTC 2017



On 12/13/2017 09:21 PM, Bas Nieuwenhuizen wrote:
> On Tue, Dec 12, 2017 at 6:08 PM, Samuel Pitoiset
> <samuel.pitoiset at gmail.com> wrote:
>> Use 16_ABGR instead of 32_ABGR if Z isn't written.
>>
>> Ported from RadeonSI.
>>
>> No CTS regressions on Polaris.
>>
>> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
>> ---
>>   src/amd/common/ac_nir_to_llvm.c | 65 ++++++++++++++++++++++++++++++++++-------
>>   src/amd/vulkan/radv_pipeline.c  | 29 ++++++++++++++----
>>   2 files changed, 78 insertions(+), 16 deletions(-)
>>
>> diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
>> index 663b27d265..5916619e97 100644
>> --- a/src/amd/common/ac_nir_to_llvm.c
>> +++ b/src/amd/common/ac_nir_to_llvm.c
>> @@ -6166,6 +6166,26 @@ si_export_mrt_color(struct nir_to_llvm_context *ctx,
>>          return true;
>>   }
>>
>> +static unsigned
>> +si_get_spi_shader_z_format(bool writes_z, bool writes_stencil,
>> +                          bool writes_samplemask)
>> +{
>> +       if (writes_z) {
>> +               /* Z needs 32 bits. */
>> +               if (writes_samplemask)
>> +                       return V_028710_SPI_SHADER_32_ABGR;
>> +               else if (writes_stencil)
>> +                       return V_028710_SPI_SHADER_32_GR;
>> +               else
>> +                       return V_028710_SPI_SHADER_32_R;
>> +       } else if (writes_stencil || writes_samplemask) {
>> +               /* Both stencil and sample mask need only 16 bits. */
>> +               return V_028710_SPI_SHADER_UINT16_ABGR;
>> +       } else {
>> +               return V_028710_SPI_SHADER_ZERO;
>> +       }
>> +}
> 
> I'm not a fan of having this function in two places. Can we export the
> format from the compiler to radv, or the other way around?

Yeah, I'm not a big fan as well. Exporting the format from the compiler 
to radv seems the best solution. I will update the patch.

> 
> Otherwise,
> 
> Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> 
>> +
>>   static void
>>   si_export_mrt_z(struct nir_to_llvm_context *ctx,
>>                  LLVMValueRef depth, LLVMValueRef stencil,
>> @@ -6184,19 +6204,42 @@ si_export_mrt_z(struct nir_to_llvm_context *ctx,
>>          args.out[2] = LLVMGetUndef(ctx->ac.f32); /* B, sample mask */
>>          args.out[3] = LLVMGetUndef(ctx->ac.f32); /* A, alpha to mask */
>>
>> -       if (depth) {
>> -               args.out[0] = depth;
>> -               args.enabled_channels |= 0x1;
>> -       }
>> +       unsigned format = si_get_spi_shader_z_format(depth != NULL,
>> +                                                    stencil != NULL,
>> +                                                    samplemask != NULL);
>> +
>> +       if (format == V_028710_SPI_SHADER_UINT16_ABGR) {
>> +               assert(!depth);
>> +               args.compr = 1; /* COMPR flag */
>> +
>> +               if (stencil) {
>> +                       /* Stencil should be in X[23:16]. */
>> +                       stencil = ac_to_integer(&ctx->ac, stencil);
>> +                       stencil = LLVMBuildShl(ctx->builder, stencil,
>> +                                              LLVMConstInt(ctx->ac.i32, 16, 0), "");
>> +                       args.out[0] = ac_to_float(&ctx->ac, stencil);
>> +                       args.enabled_channels |= 0x3;
>> +               }
>> +               if (samplemask) {
>> +                       /* SampleMask should be in Y[15:0]. */
>> +                       args.out[1] = samplemask;
>> +                       args.enabled_channels |= 0xc;
>> +               }
>> +       } else {
>> +               if (depth) {
>> +                       args.out[0] = depth;
>> +                       args.enabled_channels |= 0x1;
>> +               }
>>
>> -       if (stencil) {
>> -               args.out[1] = stencil;
>> -               args.enabled_channels |= 0x2;
>> -       }
>> +               if (stencil) {
>> +                       args.out[1] = stencil;
>> +                       args.enabled_channels |= 0x2;
>> +               }
>>
>> -       if (samplemask) {
>> -               args.out[2] = samplemask;
>> -               args.enabled_channels |= 0x4;
>> +               if (samplemask) {
>> +                       args.out[2] = samplemask;
>> +                       args.enabled_channels |= 0x4;
>> +               }
>>          }
>>
>>          /* SI (except OLAND and HAINAN) has a bug that it only looks
>> diff --git a/src/amd/vulkan/radv_pipeline.c b/src/amd/vulkan/radv_pipeline.c
>> index 0146d6935e..baaf5c4c77 100644
>> --- a/src/amd/vulkan/radv_pipeline.c
>> +++ b/src/amd/vulkan/radv_pipeline.c
>> @@ -2013,6 +2013,25 @@ radv_pipeline_stage_to_user_data_0(struct radv_pipeline *pipeline,
>>          }
>>   }
>>
>> +static unsigned
>> +si_get_spi_shader_z_format(bool writes_z, bool writes_stencil,
>> +                          bool writes_samplemask)
>> +{
>> +       if (writes_z) {
>> +               /* Z needs 32 bits. */
>> +               if (writes_samplemask)
>> +                       return V_028710_SPI_SHADER_32_ABGR;
>> +               else if (writes_stencil)
>> +                       return V_028710_SPI_SHADER_32_GR;
>> +               else
>> +                       return V_028710_SPI_SHADER_32_R;
>> +       } else if (writes_stencil || writes_samplemask) {
>> +               /* Both stencil and sample mask need only 16 bits. */
>> +               return V_028710_SPI_SHADER_UINT16_ABGR;
>> +       } else {
>> +               return V_028710_SPI_SHADER_ZERO;
>> +       }
>> +}
>>
>>   static VkResult
>>   radv_pipeline_init(struct radv_pipeline *pipeline,
>> @@ -2108,11 +2127,11 @@ radv_pipeline_init(struct radv_pipeline *pipeline,
>>          if (pipeline->device->physical_device->has_rbplus)
>>                  pipeline->graphics.db_shader_control |= S_02880C_DUAL_QUAD_DISABLE(1);
>>
>> -       pipeline->graphics.shader_z_format =
>> -               ps->info.fs.writes_sample_mask ? V_028710_SPI_SHADER_32_ABGR :
>> -               ps->info.fs.writes_stencil ? V_028710_SPI_SHADER_32_GR :
>> -               ps->info.fs.writes_z ? V_028710_SPI_SHADER_32_R :
>> -               V_028710_SPI_SHADER_ZERO;
>> +       unsigned shader_z_format =
>> +               si_get_spi_shader_z_format(ps->info.fs.writes_z,
>> +                                          ps->info.fs.writes_stencil,
>> +                                          ps->info.fs.writes_sample_mask);
>> +       pipeline->graphics.shader_z_format = shader_z_format;
>>
>>          calculate_vgt_gs_mode(pipeline);
>>          calculate_vs_outinfo(pipeline);
>> --
>> 2.15.1
>>
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>> mesa-dev at lists.freedesktop.org
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