[Mesa-dev] [PATCH 10/10] i965: use nir unrolling for scalar backend Gen7+

Connor Abbott cwabbott0 at gmail.com
Thu Sep 15 23:49:44 UTC 2016


This seems a little dubious... why restrict it to gen7+? And why only
scalar? This pass assumes SSA, but so do many other passes in core NIR
that we also run in nir_optimize(), so that shouldn't be a problem.

On Thu, Sep 15, 2016 at 3:03 AM, Timothy Arceri
<timothy.arceri at collabora.com> wrote:
> ---
>  src/compiler/glsl/glsl_parser_extras.cpp | 12 +++++----
>  src/mesa/drivers/dri/i965/brw_compiler.c | 42 +++++++++++++++++++++++---------
>  src/mesa/drivers/dri/i965/brw_nir.c      | 23 +++++++++++++----
>  3 files changed, 55 insertions(+), 22 deletions(-)
>
> diff --git a/src/compiler/glsl/glsl_parser_extras.cpp b/src/compiler/glsl/glsl_parser_extras.cpp
> index 436ddd0..a5c926a 100644
> --- a/src/compiler/glsl/glsl_parser_extras.cpp
> +++ b/src/compiler/glsl/glsl_parser_extras.cpp
> @@ -2057,12 +2057,14 @@ do_common_optimization(exec_list *ir, bool linked,
>     OPT(optimize_split_arrays, ir, linked);
>     OPT(optimize_redundant_jumps, ir);
>
> -   loop_state *ls = analyze_loop_variables(ir);
> -   if (ls->loop_found) {
> -      OPT(set_loop_controls, ir, ls);
> -      OPT(unroll_loops, ir, ls, options);
> +   if (options->MaxUnrollIterations != 0) {
> +      loop_state *ls = analyze_loop_variables(ir);
> +      if (ls->loop_found) {
> +         OPT(set_loop_controls, ir, ls);
> +         OPT(unroll_loops, ir, ls, options);
> +      }
> +      delete ls;
>     }
> -   delete ls;
>
>  #undef OPT
>
> diff --git a/src/mesa/drivers/dri/i965/brw_compiler.c b/src/mesa/drivers/dri/i965/brw_compiler.c
> index 86b1eaa..523b554 100644
> --- a/src/mesa/drivers/dri/i965/brw_compiler.c
> +++ b/src/mesa/drivers/dri/i965/brw_compiler.c
> @@ -43,18 +43,28 @@
>     .use_interpolated_input_intrinsics = true,                                 \
>     .vertex_id_zero_based = true
>
> +#define COMMON_SCALAR_OPTIONS                                                 \
> +   .lower_pack_half_2x16 = true,                                              \
> +   .lower_pack_snorm_2x16 = true,                                             \
> +   .lower_pack_snorm_4x8 = true,                                              \
> +   .lower_pack_unorm_2x16 = true,                                             \
> +   .lower_pack_unorm_4x8 = true,                                              \
> +   .lower_unpack_half_2x16 = true,                                            \
> +   .lower_unpack_snorm_2x16 = true,                                           \
> +   .lower_unpack_snorm_4x8 = true,                                            \
> +   .lower_unpack_unorm_2x16 = true,                                           \
> +   .lower_unpack_unorm_4x8 = true                                             \
> +
>  static const struct nir_shader_compiler_options scalar_nir_options = {
>     COMMON_OPTIONS,
> -   .lower_pack_half_2x16 = true,
> -   .lower_pack_snorm_2x16 = true,
> -   .lower_pack_snorm_4x8 = true,
> -   .lower_pack_unorm_2x16 = true,
> -   .lower_pack_unorm_4x8 = true,
> -   .lower_unpack_half_2x16 = true,
> -   .lower_unpack_snorm_2x16 = true,
> -   .lower_unpack_snorm_4x8 = true,
> -   .lower_unpack_unorm_2x16 = true,
> -   .lower_unpack_unorm_4x8 = true,
> +   COMMON_SCALAR_OPTIONS,
> +   .max_unroll_iterations = 0,
> +};
> +
> +static const struct nir_shader_compiler_options scalar_nir_options_gen7 = {
> +   COMMON_OPTIONS,
> +   COMMON_SCALAR_OPTIONS,
> +   .max_unroll_iterations = 32,
>  };
>
>  static const struct nir_shader_compiler_options vector_nir_options = {
> @@ -75,6 +85,7 @@ static const struct nir_shader_compiler_options vector_nir_options = {
>     .lower_unpack_unorm_2x16 = true,
>     .lower_extract_byte = true,
>     .lower_extract_word = true,
> +   .max_unroll_iterations = 0,
>  };
>
>  static const struct nir_shader_compiler_options vector_nir_options_gen6 = {
> @@ -92,6 +103,7 @@ static const struct nir_shader_compiler_options vector_nir_options_gen6 = {
>     .lower_unpack_unorm_2x16 = true,
>     .lower_extract_byte = true,
>     .lower_extract_word = true,
> +   .max_unroll_iterations = 0,
>  };
>
>  struct brw_compiler *
> @@ -119,7 +131,6 @@ brw_compiler_create(void *mem_ctx, const struct gen_device_info *devinfo)
>
>     /* We want the GLSL compiler to emit code that uses condition codes */
>     for (int i = 0; i < MESA_SHADER_STAGES; i++) {
> -      compiler->glsl_compiler_options[i].MaxUnrollIterations = 32;
>        compiler->glsl_compiler_options[i].MaxIfDepth =
>           devinfo->gen < 6 ? 16 : UINT_MAX;
>
> @@ -140,8 +151,15 @@ brw_compiler_create(void *mem_ctx, const struct gen_device_info *devinfo)
>           compiler->glsl_compiler_options[i].EmitNoIndirectSampler = true;
>
>        if (is_scalar) {
> -         compiler->glsl_compiler_options[i].NirOptions = &scalar_nir_options;
> +         if (devinfo->gen > 6) {
> +            compiler->glsl_compiler_options[i].MaxUnrollIterations = 0;
> +         } else {
> +            compiler->glsl_compiler_options[i].MaxUnrollIterations = 32;
> +         }
> +         compiler->glsl_compiler_options[i].NirOptions =
> +            devinfo->gen < 7 ? &scalar_nir_options : &scalar_nir_options_gen7;
>        } else {
> +         compiler->glsl_compiler_options[i].MaxUnrollIterations = 32;
>           compiler->glsl_compiler_options[i].NirOptions =
>              devinfo->gen < 6 ? &vector_nir_options : &vector_nir_options_gen6;
>        }
> diff --git a/src/mesa/drivers/dri/i965/brw_nir.c b/src/mesa/drivers/dri/i965/brw_nir.c
> index 0c15b55..15abb77 100644
> --- a/src/mesa/drivers/dri/i965/brw_nir.c
> +++ b/src/mesa/drivers/dri/i965/brw_nir.c
> @@ -367,8 +367,17 @@ brw_nir_lower_cs_shared(nir_shader *nir)
>  #define OPT_V(pass, ...) NIR_PASS_V(nir, pass, ##__VA_ARGS__)
>
>  static nir_shader *
> -nir_optimize(nir_shader *nir, bool is_scalar)
> +nir_optimize(nir_shader *nir, const struct brw_compiler *compiler,
> +             bool is_scalar)
>  {
> +   nir_variable_mode indirect_mask = 0;
> +   if (compiler->glsl_compiler_options[nir->stage].EmitNoIndirectInput)
> +      indirect_mask |= nir_var_shader_in;
> +   if (compiler->glsl_compiler_options[nir->stage].EmitNoIndirectOutput)
> +      indirect_mask |= nir_var_shader_out;
> +   if (compiler->glsl_compiler_options[nir->stage].EmitNoIndirectTemp)
> +      indirect_mask |= nir_var_local;
> +
>     bool progress;
>     do {
>        progress = false;
> @@ -391,6 +400,10 @@ nir_optimize(nir_shader *nir, bool is_scalar)
>        OPT(nir_opt_algebraic);
>        OPT(nir_opt_constant_folding);
>        OPT(nir_opt_dead_cf);
> +      if (nir->options->max_unroll_iterations != 0) {
> +         OPT_V(nir_to_lcssa);
> +         OPT(nir_opt_loop_unroll, indirect_mask);
> +      }
>        OPT(nir_opt_remove_phis);
>        OPT(nir_opt_undef);
>        OPT_V(nir_lower_doubles, nir_lower_drcp |
> @@ -444,7 +457,7 @@ brw_preprocess_nir(const struct brw_compiler *compiler, nir_shader *nir)
>
>     OPT(nir_split_var_copies);
>
> -   nir = nir_optimize(nir, is_scalar);
> +   nir = nir_optimize(nir, compiler, is_scalar);
>
>     if (is_scalar) {
>        OPT_V(nir_lower_load_const_to_scalar);
> @@ -466,7 +479,7 @@ brw_preprocess_nir(const struct brw_compiler *compiler, nir_shader *nir)
>     }
>
>     /* Get rid of split copies */
> -   nir = nir_optimize(nir, is_scalar);
> +   nir = nir_optimize(nir, compiler, is_scalar);
>
>     OPT(nir_remove_dead_variables, nir_var_local);
>
> @@ -491,7 +504,7 @@ brw_postprocess_nir(nir_shader *nir, const struct brw_compiler *compiler,
>     bool progress; /* Written by OPT and OPT_V */
>     (void)progress;
>
> -   nir = nir_optimize(nir, is_scalar);
> +   nir = nir_optimize(nir, compiler, is_scalar);
>
>     if (devinfo->gen >= 6) {
>        /* Try and fuse multiply-adds */
> @@ -580,7 +593,7 @@ brw_nir_apply_sampler_key(nir_shader *nir,
>
>     if (nir_lower_tex(nir, &tex_options)) {
>        nir_validate_shader(nir);
> -      nir = nir_optimize(nir, is_scalar);
> +      nir = nir_optimize(nir, compiler, is_scalar);
>     }
>
>     return nir;
> --
> 2.7.4
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev


More information about the mesa-dev mailing list