[Mesa-dev] [PATCH 26/26] nir/dead_variables: Configurably work with any variable mode

[Rob Clark]

On Fri, Mar 25, 2016 at 7:12 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> The old version of the pass only worked on globals and locals and always
> left inputs, outputs, uniforms, etc. alone.
> ---
>  src/compiler/nir/nir.h                       |  2 +-
>  src/compiler/nir/nir_remove_dead_variables.c | 33 ++++++++++++++++++++--------
>  src/gallium/drivers/freedreno/ir3/ir3_nir.c  |  2 +-
>  src/gallium/drivers/vc4/vc4_program.c        |  2 +-
>  src/mesa/drivers/dri/i965/brw_nir.c          |  2 +-
>  5 files changed, 28 insertions(+), 13 deletions(-)
>
> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
> index 03c1f76..d9e0d67 100644
> --- a/src/compiler/nir/nir.h
> +++ b/src/compiler/nir/nir.h
> @@ -2257,7 +2257,7 @@ nir_src *nir_get_io_vertex_index_src(nir_intrinsic_instr *instr);
>
>  void nir_lower_vars_to_ssa(nir_shader *shader);
>
> -bool nir_remove_dead_variables(nir_shader *shader);
> +bool nir_remove_dead_variables(nir_shader *shader, nir_variable_mode mode);
>
>  void nir_move_vec_src_uses_to_dest(nir_shader *shader);
>  bool nir_lower_vec_to_movs(nir_shader *shader);
> diff --git a/src/compiler/nir/nir_remove_dead_variables.c b/src/compiler/nir/nir_remove_dead_variables.c
> index 6519268..ad69de8 100644
> --- a/src/compiler/nir/nir_remove_dead_variables.c
> +++ b/src/compiler/nir/nir_remove_dead_variables.c
> @@ -120,7 +120,7 @@ remove_dead_vars(struct exec_list *var_list, struct set *live)
>  }
>
>  bool
> -nir_remove_dead_variables(nir_shader *shader)
> +nir_remove_dead_variables(nir_shader *shader, nir_variable_mode mode)
>  {
>     bool progress = false;
>     struct set *live =
> @@ -128,15 +128,30 @@ nir_remove_dead_variables(nir_shader *shader)
>
>     add_var_use_shader(shader, live);
>
> -   progress = remove_dead_vars(&shader->globals, live) || progress;
> +   if (mode == nir_var_uniform || mode == nir_var_all)
> +      progress = remove_dead_vars(&shader->uniforms, live) || progress;
>
> -   nir_foreach_function(shader, function) {
> -      if (function->impl) {
> -         if (remove_dead_vars(&function->impl->locals, live)) {
> -            nir_metadata_preserve(function->impl, nir_metadata_block_index |
> -                                                  nir_metadata_dominance |
> -                                                  nir_metadata_live_ssa_defs);
> -            progress = true;
> +   if (mode == nir_var_shader_in || mode == nir_var_all)
> +      progress = remove_dead_vars(&shader->inputs, live) || progress;
> +
> +   if (mode == nir_var_shader_out || mode == nir_var_all)
> +      progress = remove_dead_vars(&shader->outputs, live) || progress;
> +
> +   if (mode == nir_var_global || mode == nir_var_all)
> +      progress = remove_dead_vars(&shader->globals, live) || progress;
> +
> +   if (mode == nir_var_system_value || mode == nir_var_all)
> +      progress = remove_dead_vars(&shader->system_values, live) || progress;
> +
> +   if (mode == nir_var_local || mode == nir_var_all) {
> +      nir_foreach_function(shader, function) {
> +         if (function->impl) {
> +            if (remove_dead_vars(&function->impl->locals, live)) {
> +               nir_metadata_preserve(function->impl, nir_metadata_block_index |
> +                                                     nir_metadata_dominance |
> +                                                     nir_metadata_live_ssa_defs);
> +               progress = true;
> +            }
>           }
>        }
>     }
> diff --git a/src/gallium/drivers/freedreno/ir3/ir3_nir.c b/src/gallium/drivers/freedreno/ir3/ir3_nir.c
> index 73c65d6..04c42ff 100644
> --- a/src/gallium/drivers/freedreno/ir3/ir3_nir.c
> +++ b/src/gallium/drivers/freedreno/ir3/ir3_nir.c
> @@ -141,7 +141,7 @@ ir3_optimize_nir(struct ir3_shader *shader, nir_shader *s,
>
>         } while (progress);
>
> -       OPT_V(s, nir_remove_dead_variables);
> +       OPT_V(s, nir_remove_dead_variables, nir_var_local);

I guess need to add nir_var_global too?  Or maybe just nir_var_all for
good measure..  ttn doesn't generate locals but does globals (and w/
gtn at least I'll start seeing both)..

btw, I do remember for lower_io I wanted the mode to be a bitmask so
we could more easily deal w/ multiple modes in the same pass, but that
exceeded # of bits somewhere or other.  I suppose maybe nir_var_all is
good enough..  offhand I can't think of a scenario where we want to
lower some but not all..

BR,
-R

>
>         if (fd_mesa_debug & FD_DBG_DISASM) {
>                 debug_printf("----------------------\n");
> diff --git a/src/gallium/drivers/vc4/vc4_program.c b/src/gallium/drivers/vc4/vc4_program.c
> index 71a1ebbb..6418bc5 100644
> --- a/src/gallium/drivers/vc4/vc4_program.c
> +++ b/src/gallium/drivers/vc4/vc4_program.c
> @@ -1881,7 +1881,7 @@ vc4_shader_ntq(struct vc4_context *vc4, enum qstage stage,
>
>          vc4_optimize_nir(c->s);
>
> -        nir_remove_dead_variables(c->s);
> +        nir_remove_dead_variables(c->s, nir_var_local);
>
>          nir_convert_from_ssa(c->s, true);
>
> diff --git a/src/mesa/drivers/dri/i965/brw_nir.c b/src/mesa/drivers/dri/i965/brw_nir.c
> index c62840a..8392189 100644
> --- a/src/mesa/drivers/dri/i965/brw_nir.c
> +++ b/src/mesa/drivers/dri/i965/brw_nir.c
> @@ -468,7 +468,7 @@ brw_preprocess_nir(nir_shader *nir, bool is_scalar)
>     /* Get rid of split copies */
>     nir = nir_optimize(nir, is_scalar);
>
> -   OPT(nir_remove_dead_variables);
> +   OPT(nir_remove_dead_variables, nir_var_local);
>
>     return nir;
>  }
> --
> 2.5.0.400.gff86faf
>
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