From: Timur Kristóf Date: Fri, 13 Mar 2020 09:14:37 +0000 (+0100) Subject: nir: Collect if shader uses cross-invocation or indirect I/O. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f1dd81ae1047304a4cfb0861cb85c69a2ae776ec;p=mesa.git nir: Collect if shader uses cross-invocation or indirect I/O. The following new fields are added to tess shader info: * `tcs_cross_invocation_inputs_read` * `tcs_cross_invocation_outputs_read` These are I/O masks that are a subset of inputs_read and outputs_read and they contain which per-vertex inputs and outputs are read cross-invocation. Additionall, the following new fields are added to shader_info: * `inputs_read_indirectly` * `outputs_accessed_indirectly` * `patch_inputs_read_indirectly` * `patch_outputs_accessed_indirectly` These new fields can be used for optimizing TCS in a back-end compiler. If you can be sure that the TCS doesn't use cross-invocation inputs or outputs, you can choose a different strategy for storing VS and TCS outputs. However, such optimizations might need to be disabled when the inputs/outputs are accessed indirectly due to backend limitations, so this information is also collected. Example: RADV currently has to store all VS and TCS outputs in LDS, but for shaders when only inputs and/or outputs belonging to the current invocation ID are used, it could skip storing these in LDS entirely. Signed-off-by: Timur Kristóf Reviewed-by: Rhys Perry Part-of: --- diff --git a/src/compiler/nir/nir_gather_info.c b/src/compiler/nir/nir_gather_info.c index 44d3c523d09..d902fb7b69e 100644 --- a/src/compiler/nir/nir_gather_info.c +++ b/src/compiler/nir/nir_gather_info.c @@ -22,11 +22,54 @@ */ #include "nir.h" +#include "nir_deref.h" #include "main/menums.h" +static void +get_deref_info(nir_shader *shader, nir_variable *var, nir_deref_instr *deref, + bool *cross_invocation, bool *indirect) +{ + *cross_invocation = false; + *indirect = false; + + const bool per_vertex = nir_is_per_vertex_io(var, shader->info.stage); + + nir_deref_path path; + nir_deref_path_init(&path, deref, NULL); + assert(path.path[0]->deref_type == nir_deref_type_var); + nir_deref_instr **p = &path.path[1]; + + /* Vertex index is the outermost array index. */ + if (per_vertex) { + assert((*p)->deref_type == nir_deref_type_array); + nir_instr *vertex_index_instr = (*p)->arr.index.ssa->parent_instr; + *cross_invocation = + vertex_index_instr->type != nir_instr_type_intrinsic || + nir_instr_as_intrinsic(vertex_index_instr)->intrinsic != + nir_intrinsic_load_invocation_id; + p++; + } + + /* We always lower indirect dereferences for "compact" array vars. */ + if (!path.path[0]->var->data.compact) { + /* Non-compact array vars: find out if they are indirect. */ + for (; *p; p++) { + if ((*p)->deref_type == nir_deref_type_array) { + *indirect |= !nir_src_is_const((*p)->arr.index); + } else if ((*p)->deref_type == nir_deref_type_struct) { + /* Struct indices are always constant. */ + } else { + unreachable("Unsupported deref type"); + } + } + } + + nir_deref_path_finish(&path); +} + static void set_io_mask(nir_shader *shader, nir_variable *var, int offset, int len, - bool is_output_read) + nir_deref_instr *deref, bool is_output_read) { for (int i = 0; i < len; i++) { assert(var->data.location != -1); @@ -48,11 +91,23 @@ set_io_mask(nir_shader *shader, nir_variable *var, int offset, int len, bitfield = BITFIELD64_BIT(idx); } + bool cross_invocation; + bool indirect; + get_deref_info(shader, var, deref, &cross_invocation, &indirect); + if (var->data.mode == nir_var_shader_in) { - if (is_patch_generic) + if (is_patch_generic) { shader->info.patch_inputs_read |= bitfield; - else + if (indirect) + shader->info.patch_inputs_read_indirectly |= bitfield; + } else { shader->info.inputs_read |= bitfield; + if (indirect) + shader->info.inputs_read_indirectly |= bitfield; + } + + if (cross_invocation) + shader->info.tess.tcs_cross_invocation_inputs_read |= bitfield; if (shader->info.stage == MESA_SHADER_FRAGMENT) { shader->info.fs.uses_sample_qualifier |= var->data.sample; @@ -62,16 +117,27 @@ set_io_mask(nir_shader *shader, nir_variable *var, int offset, int len, if (is_output_read) { if (is_patch_generic) { shader->info.patch_outputs_read |= bitfield; + if (indirect) + shader->info.patch_outputs_accessed_indirectly |= bitfield; } else { shader->info.outputs_read |= bitfield; + if (indirect) + shader->info.outputs_accessed_indirectly |= bitfield; } + + if (cross_invocation) + shader->info.tess.tcs_cross_invocation_outputs_read |= bitfield; } else { - if (is_patch_generic) { - shader->info.patch_outputs_written |= bitfield; - } else if (!var->data.read_only) { - shader->info.outputs_written |= bitfield; - } - } + if (is_patch_generic) { + shader->info.patch_outputs_written |= bitfield; + if (indirect) + shader->info.patch_outputs_accessed_indirectly |= bitfield; + } else if (!var->data.read_only) { + shader->info.outputs_written |= bitfield; + if (indirect) + shader->info.outputs_accessed_indirectly |= bitfield; + } + } if (var->data.fb_fetch_output) @@ -85,7 +151,8 @@ set_io_mask(nir_shader *shader, nir_variable *var, int offset, int len, * represents a shader input or output. */ static void -mark_whole_variable(nir_shader *shader, nir_variable *var, bool is_output_read) +mark_whole_variable(nir_shader *shader, nir_variable *var, + nir_deref_instr *deref, bool is_output_read) { const struct glsl_type *type = var->type; @@ -98,7 +165,7 @@ mark_whole_variable(nir_shader *shader, nir_variable *var, bool is_output_read) var->data.compact ? DIV_ROUND_UP(glsl_get_length(type), 4) : glsl_count_attribute_slots(type, false); - set_io_mask(shader, var, 0, slots, is_output_read); + set_io_mask(shader, var, 0, slots, deref, is_output_read); } static unsigned @@ -193,7 +260,7 @@ try_mask_partial_io(nir_shader *shader, nir_variable *var, return false; } - set_io_mask(shader, var, offset, elem_width, is_output_read); + set_io_mask(shader, var, offset, elem_width, deref, is_output_read); return true; } @@ -228,7 +295,7 @@ gather_intrinsic_info(nir_intrinsic_instr *instr, nir_shader *shader, is_output_read = true; if (!try_mask_partial_io(shader, var, deref, is_output_read)) - mark_whole_variable(shader, var, is_output_read); + mark_whole_variable(shader, var, deref, is_output_read); /* We need to track which input_reads bits correspond to a * dvec3/dvec4 input attribute */ @@ -462,6 +529,7 @@ nir_shader_gather_info(nir_shader *shader, nir_function_impl *entrypoint) shader->info.num_textures = 0; shader->info.num_images = 0; shader->info.last_msaa_image = -1; + nir_foreach_variable(var, &shader->uniforms) { /* Bindless textures and images don't use non-bindless slots. */ if (var->data.bindless) @@ -483,6 +551,11 @@ nir_shader_gather_info(nir_shader *shader, nir_function_impl *entrypoint) shader->info.patch_inputs_read = 0; shader->info.patch_outputs_written = 0; shader->info.system_values_read = 0; + shader->info.inputs_read_indirectly = 0; + shader->info.outputs_accessed_indirectly = 0; + shader->info.patch_inputs_read_indirectly = 0; + shader->info.patch_outputs_accessed_indirectly = 0; + if (shader->info.stage == MESA_SHADER_VERTEX) { shader->info.vs.double_inputs = 0; } @@ -492,6 +565,11 @@ nir_shader_gather_info(nir_shader *shader, nir_function_impl *entrypoint) shader->info.fs.uses_demote = false; shader->info.fs.needs_helper_invocations = false; } + if (shader->info.stage == MESA_SHADER_TESS_CTRL) { + shader->info.tess.tcs_cross_invocation_inputs_read = 0; + shader->info.tess.tcs_cross_invocation_outputs_read = 0; + } + shader->info.writes_memory = shader->info.has_transform_feedback_varyings; void *dead_ctx = ralloc_context(NULL); diff --git a/src/compiler/shader_info.h b/src/compiler/shader_info.h index fcd235112a0..48a32f6f4ff 100644 --- a/src/compiler/shader_info.h +++ b/src/compiler/shader_info.h @@ -134,6 +134,15 @@ typedef struct shader_info { /* Which patch outputs are read */ uint32_t patch_outputs_read; + /* Which inputs are read indirectly (subset of inputs_read) */ + uint64_t inputs_read_indirectly; + /* Which outputs are read or written indirectly */ + uint64_t outputs_accessed_indirectly; + /* Which patch inputs are read indirectly (subset of patch_inputs_read) */ + uint64_t patch_inputs_read_indirectly; + /* Which patch outputs are read or written indirectly */ + uint64_t patch_outputs_accessed_indirectly; + /** Bitfield of which textures are used */ uint32_t textures_used; @@ -321,6 +330,16 @@ typedef struct shader_info { uint8_t tcs_vertices_out; enum gl_tess_spacing spacing:2; + /* Bit mask of TCS per-vertex inputs (VS outputs) that are used + * with a vertex index that is NOT the invocation id + */ + uint64_t tcs_cross_invocation_inputs_read; + + /* Bit mask of TCS per-vertex outputs that are used + * with a vertex index that is NOT the invocation id + */ + uint64_t tcs_cross_invocation_outputs_read; + /** Is the vertex order counterclockwise? */ bool ccw:1; bool point_mode:1;