[Mesa-dev] [PATCH 1/2] tgsi/scan: add uses_derivatives

[Brian Paul]

On 06/01/2016 05:28 AM, Nicolai Hähnle wrote:
> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>
> Cc: 12.0 <mesa-stable at lists.freedesktop.org>
> ---
>   src/gallium/auxiliary/tgsi/tgsi_scan.c | 26 ++++++++++++++++++++++++++
>   src/gallium/auxiliary/tgsi/tgsi_scan.h |  1 +
>   2 files changed, 27 insertions(+)
>
> diff --git a/src/gallium/auxiliary/tgsi/tgsi_scan.c b/src/gallium/auxiliary/tgsi/tgsi_scan.c
> index 1baf031..d202ab1 100644
> --- a/src/gallium/auxiliary/tgsi/tgsi_scan.c
> +++ b/src/gallium/auxiliary/tgsi/tgsi_scan.c
> @@ -68,6 +68,29 @@ is_texture_inst(unsigned opcode)
>              tgsi_get_opcode_info(opcode)->is_tex);
>   }
>
> +
> +/**
> + * Is the opcode an instruction which computes a derivative explicitly or
> + * implicitly?
> + */
> +static bool
> +computes_derivative(unsigned opcode)
> +{
> +   if (tgsi_get_opcode_info(opcode)->is_tex) {
> +      return opcode != TGSI_OPCODE_TXD &&
> +             opcode != TGSI_OPCODE_TXL &&
> +             opcode != TGSI_OPCODE_TXL2 &&
> +             opcode != TGSI_OPCODE_TXF &&
> +             opcode != TGSI_OPCODE_TXQ &&
> +             opcode != TGSI_OPCODE_TXQ_LZ &&
> +             opcode != TGSI_OPCODE_TXQS;
> +   }
> +
> +   return opcode == TGSI_OPCODE_DDX || opcode == TGSI_OPCODE_DDX_FINE ||
> +          opcode == TGSI_OPCODE_DDY || opcode == TGSI_OPCODE_DDY_FINE;
> +}
> +
> +
>   static void
>   scan_instruction(struct tgsi_shader_info *info,
>                    const struct tgsi_full_instruction *fullinst,
> @@ -263,6 +286,9 @@ scan_instruction(struct tgsi_shader_info *info,
>      if (is_mem_inst)
>         info->num_memory_instructions++;
>
> +   if (computes_derivative(fullinst->Instruction.Opcode))
> +      info->uses_derivatives = true;
> +
>      info->num_instructions++;
>   }
>
> diff --git a/src/gallium/auxiliary/tgsi/tgsi_scan.h b/src/gallium/auxiliary/tgsi/tgsi_scan.h
> index 31adce7..f7eefa4 100644
> --- a/src/gallium/auxiliary/tgsi/tgsi_scan.h
> +++ b/src/gallium/auxiliary/tgsi/tgsi_scan.h
> @@ -115,6 +115,7 @@ struct tgsi_shader_info
>      boolean writes_memory; /**< contains stores or atomics to buffers or images */
>      boolean is_msaa_sampler[PIPE_MAX_SAMPLERS];
>      boolean uses_doubles; /**< uses any of the double instructions */
> +   boolean uses_derivatives;
>      unsigned clipdist_writemask;
>      unsigned culldist_writemask;
>      unsigned num_written_culldistance;
>

Reviewed-by: Brian Paul <brianp at vmware.com>