From 5ef2b8f1f2ebcdb4ffe5c98b3f4f48e584cb4b22 Mon Sep 17 00:00:00 2001 From: Jason Ekstrand Date: Wed, 6 Mar 2019 15:21:51 -0600 Subject: [PATCH] nir: Add a pass for lowering IO back to vector when possible This pass tries to turn scalar and array-of-scalar IO variables into vector IO variables whenever possible. Reviewed-by: Connor Abbott Cc: "19.0" --- src/compiler/Makefile.sources | 1 + src/compiler/nir/meson.build | 1 + src/compiler/nir/nir.h | 1 + .../nir/nir_lower_io_to_temporaries.c | 3 +- src/compiler/nir/nir_lower_io_to_vector.c | 387 ++++++++++++++++++ 5 files changed, 392 insertions(+), 1 deletion(-) create mode 100644 src/compiler/nir/nir_lower_io_to_vector.c diff --git a/src/compiler/Makefile.sources b/src/compiler/Makefile.sources index faa7ea9aba1..7154fd1bc7d 100644 --- a/src/compiler/Makefile.sources +++ b/src/compiler/Makefile.sources @@ -251,6 +251,7 @@ NIR_FILES = \ nir/nir_lower_io_arrays_to_elements.c \ nir/nir_lower_io_to_temporaries.c \ nir/nir_lower_io_to_scalar.c \ + nir/nir_lower_io_to_vector.c \ nir/nir_lower_packing.c \ nir/nir_lower_passthrough_edgeflags.c \ nir/nir_lower_patch_vertices.c \ diff --git a/src/compiler/nir/meson.build b/src/compiler/nir/meson.build index 93b15c7ce1f..514f5ceaa56 100644 --- a/src/compiler/nir/meson.build +++ b/src/compiler/nir/meson.build @@ -133,6 +133,7 @@ files_libnir = files( 'nir_lower_io_arrays_to_elements.c', 'nir_lower_io_to_temporaries.c', 'nir_lower_io_to_scalar.c', + 'nir_lower_io_to_vector.c', 'nir_lower_packing.c', 'nir_lower_passthrough_edgeflags.c', 'nir_lower_patch_vertices.c', diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h index 54f3f209950..22831cf3cc1 100644 --- a/src/compiler/nir/nir.h +++ b/src/compiler/nir/nir.h @@ -3061,6 +3061,7 @@ void nir_lower_io_arrays_to_elements_no_indirects(nir_shader *shader, bool outputs_only); void nir_lower_io_to_scalar(nir_shader *shader, nir_variable_mode mask); void nir_lower_io_to_scalar_early(nir_shader *shader, nir_variable_mode mask); +bool nir_lower_io_to_vector(nir_shader *shader, nir_variable_mode mask); bool nir_lower_uniforms_to_ubo(nir_shader *shader, int multiplier); diff --git a/src/compiler/nir/nir_lower_io_to_temporaries.c b/src/compiler/nir/nir_lower_io_to_temporaries.c index 7602637d428..d2b069d3d68 100644 --- a/src/compiler/nir/nir_lower_io_to_temporaries.c +++ b/src/compiler/nir/nir_lower_io_to_temporaries.c @@ -85,7 +85,8 @@ emit_output_copies_impl(struct lower_io_state *state, nir_function_impl *impl) continue; nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); - if (intrin->intrinsic == nir_intrinsic_emit_vertex) { + if (intrin->intrinsic == nir_intrinsic_emit_vertex || + intrin->intrinsic == nir_intrinsic_emit_vertex_with_counter) { b.cursor = nir_before_instr(&intrin->instr); emit_copies(&b, &state->shader->outputs, &state->old_outputs); } diff --git a/src/compiler/nir/nir_lower_io_to_vector.c b/src/compiler/nir/nir_lower_io_to_vector.c new file mode 100644 index 00000000000..d979962373d --- /dev/null +++ b/src/compiler/nir/nir_lower_io_to_vector.c @@ -0,0 +1,387 @@ +/* + * Copyright © 2019 Intel Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + */ + +#include "nir.h" +#include "nir_builder.h" +#include "nir_deref.h" + +/** @file nir_lower_io_to_vector.c + * + * Merges compatible input/output variables residing in different components + * of the same location. It's expected that further passes such as + * nir_lower_io_to_temporaries will combine loads and stores of the merged + * variables, producing vector nir_load_input/nir_store_output instructions + * when all is said and done. + */ + +static const struct glsl_type * +resize_array_vec_type(const struct glsl_type *type, unsigned num_components) +{ + if (glsl_type_is_array(type)) { + const struct glsl_type *arr_elem = + resize_array_vec_type(glsl_get_array_element(type), num_components); + return glsl_array_type(arr_elem, glsl_get_length(type), 0); + } else { + assert(glsl_type_is_vector_or_scalar(type)); + return glsl_vector_type(glsl_get_base_type(type), num_components); + } +} + +static bool +variable_can_rewrite(const nir_variable *var) +{ + /* Only touch user defined varyings as these are the only ones we split */ + if (var->data.location < VARYING_SLOT_VAR0) + return false; + + /* Skip complex types we don't split in the first place */ + if (!glsl_type_is_vector_or_scalar(glsl_without_array(var->type))) + return false; + + /* TODO: add 64/16bit support ? */ + if (glsl_get_bit_size(glsl_without_array(var->type)) != 32) + return false; + + return true; +} + +static bool +variables_can_merge(nir_shader *shader, + const nir_variable *a, const nir_variable *b) +{ + const struct glsl_type *a_type_tail = a->type; + const struct glsl_type *b_type_tail = b->type; + + /* They must have the same array structure */ + while (glsl_type_is_array(a_type_tail)) { + if (!glsl_type_is_array(b_type_tail)) + return false; + + if (glsl_get_length(a_type_tail) != glsl_get_length(b_type_tail)) + return false; + + a_type_tail = glsl_get_array_element(a_type_tail); + b_type_tail = glsl_get_array_element(b_type_tail); + } + + if (!glsl_type_is_vector_or_scalar(a_type_tail) || + !glsl_type_is_vector_or_scalar(b_type_tail)) + return false; + + if (glsl_get_base_type(a->type) != glsl_get_base_type(b->type)) + return false; + + assert(a->data.mode == b->data.mode); + if (shader->info.stage == MESA_SHADER_FRAGMENT && + a->data.mode == nir_var_shader_in && + a->data.interpolation != b->data.interpolation) + return false; + + return true; +} + +static bool +create_new_io_vars(nir_shader *shader, struct exec_list *io_list, + nir_variable *old_vars[MAX_VARYINGS_INCL_PATCH][4], + nir_variable *new_vars[MAX_VARYINGS_INCL_PATCH][4]) +{ + if (exec_list_is_empty(io_list)) + return false; + + nir_foreach_variable(var, io_list) { + if (variable_can_rewrite(var)) { + unsigned loc = var->data.location - VARYING_SLOT_VAR0; + unsigned frac = var->data.location_frac; + old_vars[loc][frac] = var; + } + } + + bool merged_any_vars = false; + + /* We don't handle combining vars of different type e.g. different array + * lengths. + */ + for (unsigned loc = 0; loc < MAX_VARYINGS_INCL_PATCH; loc++) { + unsigned frac = 0; + while (frac < 4) { + nir_variable *first_var = old_vars[loc][frac]; + if (!first_var) { + frac++; + continue; + } + + int first = frac; + bool found_merge = false; + + while (frac < 4) { + nir_variable *var = old_vars[loc][frac]; + if (!var) + break; + + if (var != first_var) { + if (!variables_can_merge(shader, first_var, var)) + break; + + found_merge = true; + } + + const unsigned num_components = + glsl_get_components(glsl_without_array(var->type)); + + /* We had better not have any overlapping vars */ + for (unsigned i = 1; i < num_components; i++) + assert(old_vars[loc][frac + i] == NULL); + + frac += num_components; + } + + if (!found_merge) + continue; + + merged_any_vars = true; + + nir_variable *var = nir_variable_clone(old_vars[loc][first], shader); + var->data.location_frac = first; + var->type = resize_array_vec_type(var->type, frac - first); + + nir_shader_add_variable(shader, var); + for (unsigned i = first; i < frac; i++) + new_vars[loc][i] = var; + } + } + + return merged_any_vars; +} + +static nir_deref_instr * +build_array_deref_of_new_var(nir_builder *b, nir_variable *new_var, + nir_deref_instr *leader) +{ + if (leader->deref_type == nir_deref_type_var) + return nir_build_deref_var(b, new_var); + + nir_deref_instr *parent = + build_array_deref_of_new_var(b, new_var, nir_deref_instr_parent(leader)); + + return nir_build_deref_follower(b, parent, leader); +} + +static bool +nir_lower_io_to_vector_impl(nir_function_impl *impl, nir_variable_mode modes) +{ + assert(!(modes & ~(nir_var_shader_in | nir_var_shader_out))); + + nir_builder b; + nir_builder_init(&b, impl); + + nir_metadata_require(impl, nir_metadata_dominance); + + nir_shader *shader = impl->function->shader; + nir_variable *old_inputs[MAX_VARYINGS_INCL_PATCH][4] = {0}; + nir_variable *new_inputs[MAX_VARYINGS_INCL_PATCH][4] = {0}; + nir_variable *old_outputs[MAX_VARYINGS_INCL_PATCH][4] = {0}; + nir_variable *new_outputs[MAX_VARYINGS_INCL_PATCH][4] = {0}; + + if (modes & nir_var_shader_in) { + /* Vertex shaders support overlapping inputs. We don't do those */ + assert(b.shader->info.stage != MESA_SHADER_VERTEX); + + /* If we don't actually merge any variables, remove that bit from modes + * so we don't bother doing extra non-work. + */ + if (!create_new_io_vars(shader, &shader->inputs, + old_inputs, new_inputs)) + modes &= ~nir_var_shader_in; + } + + if (modes & nir_var_shader_out) { + /* Fragment shader outputs are always vec4. You shouldn't have + * scalarized them and it doesn't make sense to vectorize them. + */ + assert(b.shader->info.stage != MESA_SHADER_FRAGMENT); + + /* If we don't actually merge any variables, remove that bit from modes + * so we don't bother doing extra non-work. + */ + if (!create_new_io_vars(shader, &shader->outputs, + old_outputs, new_outputs)) + modes &= ~nir_var_shader_out; + } + + if (!modes) + return false; + + bool progress = false; + + /* Actually lower all the IO load/store intrinsics. Load instructions are + * lowered to a vector load and an ALU instruction to grab the channels we + * want. Outputs are lowered to a write-masked store of the vector output. + * For non-TCS outputs, we then run nir_lower_io_to_temporaries at the end + * to clean up the partial writes. + */ + nir_foreach_block(block, impl) { + nir_foreach_instr_safe(instr, block) { + if (instr->type != nir_instr_type_intrinsic) + continue; + + nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); + + switch (intrin->intrinsic) { + case nir_intrinsic_load_deref: + case nir_intrinsic_interp_deref_at_centroid: + case nir_intrinsic_interp_deref_at_sample: + case nir_intrinsic_interp_deref_at_offset: { + nir_deref_instr *old_deref = nir_src_as_deref(intrin->src[0]); + if (!(old_deref->mode & modes)) + break; + + if (old_deref->mode == nir_var_shader_out) + assert(b.shader->info.stage == MESA_SHADER_TESS_CTRL); + + nir_variable *old_var = nir_deref_instr_get_variable(old_deref); + if (old_var->data.location < VARYING_SLOT_VAR0) + break; + + const unsigned loc = old_var->data.location - VARYING_SLOT_VAR0; + const unsigned old_frac = old_var->data.location_frac; + nir_variable *new_var = old_deref->mode == nir_var_shader_in ? + new_inputs[loc][old_frac] : + new_outputs[loc][old_frac]; + if (!new_var) + break; + + assert(new_var->data.location == VARYING_SLOT_VAR0 + loc); + const unsigned new_frac = new_var->data.location_frac; + + nir_component_mask_t vec4_comp_mask = + ((1 << intrin->num_components) - 1) << old_frac; + + b.cursor = nir_before_instr(&intrin->instr); + + /* Rewrite the load to use the new variable and only select a + * portion of the result. + */ + nir_deref_instr *new_deref = + build_array_deref_of_new_var(&b, new_var, old_deref); + assert(glsl_type_is_vector(new_deref->type)); + nir_instr_rewrite_src(&intrin->instr, &intrin->src[0], + nir_src_for_ssa(&new_deref->dest.ssa)); + + intrin->num_components = + glsl_get_components(new_deref->type); + intrin->dest.ssa.num_components = intrin->num_components; + + b.cursor = nir_after_instr(&intrin->instr); + + nir_ssa_def *new_vec = nir_channels(&b, &intrin->dest.ssa, + vec4_comp_mask >> new_frac); + nir_ssa_def_rewrite_uses_after(&intrin->dest.ssa, + nir_src_for_ssa(new_vec), + new_vec->parent_instr); + + progress = true; + break; + } + + case nir_intrinsic_store_deref: { + nir_deref_instr *old_deref = nir_src_as_deref(intrin->src[0]); + if (old_deref->mode != nir_var_shader_out) + break; + + nir_variable *old_var = nir_deref_instr_get_variable(old_deref); + if (old_var->data.location < VARYING_SLOT_VAR0) + break; + + const unsigned loc = old_var->data.location - VARYING_SLOT_VAR0; + const unsigned old_frac = old_var->data.location_frac; + nir_variable *new_var = new_outputs[loc][old_frac]; + if (!new_var) + break; + + assert(new_var->data.location == VARYING_SLOT_VAR0 + loc); + const unsigned new_frac = new_var->data.location_frac; + + b.cursor = nir_before_instr(&intrin->instr); + + /* Rewrite the store to be a masked store to the new variable */ + nir_deref_instr *new_deref = + build_array_deref_of_new_var(&b, new_var, old_deref); + assert(glsl_type_is_vector(new_deref->type)); + nir_instr_rewrite_src(&intrin->instr, &intrin->src[0], + nir_src_for_ssa(&new_deref->dest.ssa)); + + intrin->num_components = + glsl_get_components(new_deref->type); + + nir_component_mask_t old_wrmask = nir_intrinsic_write_mask(intrin); + + assert(intrin->src[1].is_ssa); + nir_ssa_def *old_value = intrin->src[1].ssa; + nir_ssa_def *comps[4]; + for (unsigned c = 0; c < intrin->num_components; c++) { + if (new_frac + c >= old_frac && + (old_wrmask & 1 << (new_frac + c - old_frac))) { + comps[c] = nir_channel(&b, old_value, + new_frac + c - old_frac); + } else { + comps[c] = nir_ssa_undef(&b, old_value->num_components, + old_value->bit_size); + } + } + nir_ssa_def *new_value = nir_vec(&b, comps, intrin->num_components); + nir_instr_rewrite_src(&intrin->instr, &intrin->src[1], + nir_src_for_ssa(new_value)); + + nir_intrinsic_set_write_mask(intrin, + old_wrmask << (old_frac - new_frac)); + + progress = true; + break; + } + + default: + break; + } + } + } + + if (progress) { + nir_metadata_preserve(impl, nir_metadata_block_index | + nir_metadata_dominance); + } + + return progress; +} + +bool +nir_lower_io_to_vector(nir_shader *shader, nir_variable_mode modes) +{ + bool progress = false; + + nir_foreach_function(function, shader) { + if (function->impl) + progress |= nir_lower_io_to_vector_impl(function->impl, modes); + } + + return progress; +} -- 2.30.2