[Mesa-dev] [PATCH 05/14] glsl_to_tgsi: reduce the size of glsl_to_tgsi_instruction using bitfields

[Roland Scheidegger]

Am 17.10.2016 um 15:39 schrieb Marek Olšák:
> From: Marek Olšák <marek.olsak at amd.com>
> 
> sizeof(glsl_to_tgsi_instruction): 464 -> 416
> ---
>  src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 33 +++++++++++++++---------------
>  1 file changed, 16 insertions(+), 17 deletions(-)
> 
> diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> index 78d9409..b3654fe 100644
> --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> @@ -263,42 +263,41 @@ st_dst_reg::st_dst_reg(st_src_reg reg)
>     this->index2D = reg.index2D;
>     this->reladdr2 = reg.reladdr2;
>     this->has_index2 = reg.has_index2;
>     this->array_id = reg.array_id;
>  }
>  
>  class glsl_to_tgsi_instruction : public exec_node {
>  public:
>     DECLARE_RALLOC_CXX_OPERATORS(glsl_to_tgsi_instruction)
>  
> -   unsigned op;
>     st_dst_reg dst[2];
>     st_src_reg src[4];
> -   /** Pointer to the ir source this tree came from for debugging */
> -   ir_instruction *ir;
> -   GLboolean cond_update;
> -   bool saturate;
> -   bool is_64bit_expanded;
>     st_src_reg sampler; /**< sampler register */
> -   int sampler_base;
> -   int sampler_array_size; /**< 1-based size of sampler array, 1 if not array */
> -   int tex_target; /**< One of TEXTURE_*_INDEX */
> -   glsl_base_type tex_type;
> -   GLboolean tex_shadow;
> -   unsigned image_format;
> -
>     st_src_reg tex_offsets[MAX_GLSL_TEXTURE_OFFSET];
> -   unsigned tex_offset_num_offset;
> -   int dead_mask; /**< Used in dead code elimination */
> -
>     st_src_reg buffer; /**< buffer register */
> -   unsigned buffer_access; /**< buffer access type */
> +
> +   /** Pointer to the ir source this tree came from for debugging */
> +   ir_instruction *ir;
> +
> +   unsigned op:8; /**< TGSI opcode */
Maybe should throw in some static assert somewhere that TGSI_OPCODE_LAST
is <= 255.
Given how close we're to the limit I wouldn't quite bet on it staying 8
bits forever (though of course it would need some changes elsewhere too).

Roland



> +   unsigned saturate:1;
> +   unsigned is_64bit_expanded:1;
> +   unsigned sampler_base:5;
> +   unsigned sampler_array_size:6; /**< 1-based size of sampler array, 1 if not array */
> +   unsigned tex_target:4; /**< One of TEXTURE_*_INDEX */
> +   glsl_base_type tex_type:4;
> +   unsigned tex_shadow:1;
> +   unsigned image_format:9;
> +   unsigned tex_offset_num_offset:3;
> +   unsigned dead_mask:4; /**< Used in dead code elimination */
> +   unsigned buffer_access:3; /**< buffer access type */
>  
>     class function_entry *function; /* Set on TGSI_OPCODE_CAL or TGSI_OPCODE_BGNSUB */
>     const struct tgsi_opcode_info *info;
>  };
>  
>  class variable_storage : public exec_node {
>  public:
>     variable_storage(ir_variable *var, gl_register_file file, int index,
>                      unsigned array_id = 0)
>        : file(file), index(index), component(0), var(var), array_id(array_id)
>