From 70be9afccb23aa636272b782f7b72b0a23d3d9d4 Mon Sep 17 00:00:00 2001 From: Timothy Arceri Date: Mon, 10 Dec 2018 19:36:47 +1100 Subject: [PATCH] nir: link time opt duplicate varyings If we are outputting the same value to more than one output component rewrite the inputs to read from a single component. This will allow the duplicate varying components to be optimised away by the existing opts. shader-db results i965 (SKL): total instructions in shared programs: 12869230 -> 12860886 (-0.06%) instructions in affected programs: 322601 -> 314257 (-2.59%) helped: 3080 HURT: 8 total cycles in shared programs: 317792574 -> 317730593 (-0.02%) cycles in affected programs: 2584925 -> 2522944 (-2.40%) helped: 2975 HURT: 477 shader-db results radeonsi (VEGA): SGPRS: 31576 -> 31664 (0.28 %) VGPRS: 17484 -> 17064 (-2.40 %) Spilled SGPRs: 184 -> 167 (-9.24 %) Spilled VGPRs: 0 -> 0 (0.00 %) Private memory VGPRs: 0 -> 0 (0.00 %) Scratch size: 0 -> 0 (0.00 %) dwords per thread Code Size: 583340 -> 569368 (-2.40 %) bytes LDS: 0 -> 0 (0.00 %) blocks Max Waves: 6162 -> 6270 (1.75 %) Wait states: 0 -> 0 (0.00 %) vkpipeline-db results RADV (VEGA): Totals from affected shaders: SGPRS: 14880 -> 15080 (1.34 %) VGPRS: 10872 -> 10888 (0.15 %) Spilled SGPRs: 0 -> 0 (0.00 %) Spilled VGPRs: 0 -> 0 (0.00 %) Private memory VGPRs: 0 -> 0 (0.00 %) Scratch size: 0 -> 0 (0.00 %) dwords per thread Code Size: 674016 -> 668396 (-0.83 %) bytes LDS: 0 -> 0 (0.00 %) blocks Max Waves: 2708 -> 2704 (-0.15 %) Wait states: 0 -> 0 (0.00 % V2: bunch of tidy ups suggested by Jason Reviewed-by: Eric Anholt --- src/compiler/nir/nir_linking_helpers.c | 88 ++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) diff --git a/src/compiler/nir/nir_linking_helpers.c b/src/compiler/nir/nir_linking_helpers.c index c52e926ecbb..ecd15998f49 100644 --- a/src/compiler/nir/nir_linking_helpers.c +++ b/src/compiler/nir/nir_linking_helpers.c @@ -560,6 +560,27 @@ nir_link_xfb_varyings(nir_shader *producer, nir_shader *consumer) } } +static bool +does_varying_match(nir_variable *out_var, nir_variable *in_var) +{ + if (in_var->data.location == out_var->data.location && + in_var->data.location_frac == out_var->data.location_frac) + return true; + + return false; +} + +static nir_variable * +get_matching_input_var(nir_shader *consumer, nir_variable *out_var) +{ + nir_foreach_variable(var, &consumer->inputs) { + if (does_varying_match(out_var, var)) + return var; + } + + return NULL; +} + static bool can_replace_varying(nir_variable *out_var) { @@ -635,6 +656,53 @@ replace_constant_input(nir_shader *shader, nir_intrinsic_instr *store_intr) return progress; } +static bool +replace_duplicate_input(nir_shader *shader, nir_variable *input_var, + nir_intrinsic_instr *dup_store_intr) +{ + assert(input_var); + + nir_function_impl *impl = nir_shader_get_entrypoint(shader); + + nir_builder b; + nir_builder_init(&b, impl); + + nir_variable *dup_out_var = + nir_deref_instr_get_variable(nir_src_as_deref(dup_store_intr->src[0])); + + bool progress = false; + nir_foreach_block(block, impl) { + nir_foreach_instr(instr, block) { + if (instr->type != nir_instr_type_intrinsic) + continue; + + nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr); + if (intr->intrinsic != nir_intrinsic_load_deref) + continue; + + nir_deref_instr *in_deref = nir_src_as_deref(intr->src[0]); + if (in_deref->mode != nir_var_shader_in) + continue; + + nir_variable *in_var = nir_deref_instr_get_variable(in_deref); + + if (!does_varying_match(dup_out_var, in_var) || + in_var->data.interpolation != input_var->data.interpolation || + get_interp_loc(in_var) != get_interp_loc(input_var)) + continue; + + b.cursor = nir_before_instr(instr); + + nir_ssa_def *load = nir_load_var(&b, input_var); + nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(load)); + + progress = true; + } + } + + return progress; +} + bool nir_link_opt_varyings(nir_shader *producer, nir_shader *consumer) { @@ -648,6 +716,10 @@ nir_link_opt_varyings(nir_shader *producer, nir_shader *consumer) nir_function_impl *impl = nir_shader_get_entrypoint(producer); + struct hash_table *varying_values = + _mesa_hash_table_create(NULL, _mesa_hash_pointer, + _mesa_key_pointer_equal); + /* If we find a store in the last block of the producer we can be sure this * is the only possible value for this output. */ @@ -671,8 +743,24 @@ nir_link_opt_varyings(nir_shader *producer, nir_shader *consumer) if (intr->src[1].ssa->parent_instr->type == nir_instr_type_load_const) { progress |= replace_constant_input(consumer, intr); + } else { + struct hash_entry *entry = + _mesa_hash_table_search(varying_values, intr->src[1].ssa); + if (entry) { + progress |= replace_duplicate_input(consumer, + (nir_variable *) entry->data, + intr); + } else { + nir_variable *in_var = get_matching_input_var(consumer, out_var); + if (in_var) { + _mesa_hash_table_insert(varying_values, intr->src[1].ssa, + in_var); + } + } } } + _mesa_hash_table_destroy(varying_values, NULL); + return progress; } -- 2.30.2