[Mesa-dev] [PATCH] radv: enable denorms for 64-bit and 16-bit floats

[Bas Nieuwenhuizen]

Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>

On Thu, Dec 28, 2017 at 10:55 PM, Samuel Pitoiset
<samuel.pitoiset at gmail.com> wrote:
> Similar to RadeonSI.
>
> This fixes:
> dEQP-VK.image.texel_view_compatible.graphic.basic.attachment_read.bc*r16g16b16a16_sfloat
> dEQP-VK.image.extended_usage_bit.attachment_write.r16_sfloat
>
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
>  src/amd/common/ac_nir_to_llvm.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>
> diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
> index d9f2cb408c..9d9a1f911b 100644
> --- a/src/amd/common/ac_nir_to_llvm.c
> +++ b/src/amd/common/ac_nir_to_llvm.c
> @@ -6879,6 +6879,20 @@ static void ac_compile_llvm_module(LLVMTargetMachineRef tm,
>         /* +3 for scratch wave offset and VCC */
>         config->num_sgprs = MAX2(config->num_sgprs,
>                                  shader_info->num_input_sgprs + 3);
> +
> +       /* Enable 64-bit and 16-bit denormals, because there is no performance
> +        * cost.
> +        *
> +        * If denormals are enabled, all floating-point output modifiers are
> +        * ignored.
> +        *
> +        * Don't enable denormals for 32-bit floats, because:
> +        * - Floating-point output modifiers would be ignored by the hw.
> +        * - Some opcodes don't support denormals, such as v_mad_f32. We would
> +        *   have to stop using those.
> +        * - SI & CI would be very slow.
> +        */
> +       config->float_mode |= V_00B028_FP_64_DENORMS;
>  }
>
>  static void
> --
> 2.15.1
>
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