| /* |
| * Copyright © 2014 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. |
| * |
| * Authors: |
| * Connor Abbott (cwabbott0@gmail.com) |
| * |
| */ |
| |
| #include "nir.h" |
| #include "nir_builder.h" |
| |
| static bool |
| deref_used_for_not_store(nir_deref_instr *deref) |
| { |
| nir_foreach_use(src, &deref->def) { |
| switch (nir_src_parent_instr(src)->type) { |
| case nir_instr_type_deref: |
| if (deref_used_for_not_store(nir_instr_as_deref(nir_src_parent_instr(src)))) |
| return true; |
| break; |
| |
| case nir_instr_type_intrinsic: { |
| nir_intrinsic_instr *intrin = |
| nir_instr_as_intrinsic(nir_src_parent_instr(src)); |
| /* The first source of copy and store intrinsics is the deref to |
| * write. Don't record those. |
| */ |
| if ((intrin->intrinsic != nir_intrinsic_store_deref && |
| intrin->intrinsic != nir_intrinsic_copy_deref) || |
| src != &intrin->src[0]) |
| return true; |
| break; |
| } |
| |
| default: |
| /* If it's used by any other instruction type (most likely a texture |
| * or call instruction), consider it used. |
| */ |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| static void |
| add_var_use_deref(nir_deref_instr *deref, struct set *live) |
| { |
| if (deref->deref_type != nir_deref_type_var) |
| return; |
| |
| /* Since these local variables don't escape the shader, writing doesn't |
| * make them live. Only keep them if they are used by some intrinsic. |
| */ |
| if ((deref->var->data.mode & (nir_var_function_temp | |
| nir_var_shader_temp)) && |
| !deref_used_for_not_store(deref)) |
| return; |
| |
| /* |
| * Shared memory blocks (interface type) alias each other, so be |
| * conservative in that case. |
| */ |
| if ((deref->var->data.mode & nir_var_mem_shared) && |
| !glsl_type_is_interface(deref->var->type) && |
| !deref_used_for_not_store(deref)) |
| return; |
| |
| nir_variable *var = deref->var; |
| do { |
| _mesa_set_add(live, var); |
| /* Also mark the chain of variables used to initialize it. */ |
| var = var->pointer_initializer; |
| } while (var); |
| } |
| |
| static void |
| add_var_use_shader(nir_shader *shader, struct set *live, nir_variable_mode modes) |
| { |
| nir_foreach_function_impl(impl, shader) { |
| nir_foreach_block(block, impl) { |
| nir_foreach_instr(instr, block) { |
| if (instr->type == nir_instr_type_deref) |
| add_var_use_deref(nir_instr_as_deref(instr), live); |
| } |
| } |
| } |
| } |
| |
| static bool |
| remove_dead_var_writes(nir_builder *b, nir_instr *instr, void *_) |
| { |
| if (instr->type == nir_instr_type_deref) { |
| nir_deref_instr *deref = nir_instr_as_deref(instr); |
| if (deref->deref_type == nir_deref_type_cast && |
| !nir_deref_instr_parent(deref)) |
| return false; |
| |
| nir_variable_mode parent_modes; |
| if (deref->deref_type == nir_deref_type_var) |
| parent_modes = deref->var->data.mode; |
| else |
| parent_modes = nir_deref_instr_parent(deref)->modes; |
| |
| /* If the parent mode is 0, then it references a dead variable. |
| * Flag this deref as dead and remove it. |
| */ |
| if (parent_modes != 0) |
| return false; |
| |
| deref->modes = 0; |
| } else if (instr->type == nir_instr_type_intrinsic) { |
| nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); |
| if (!(intrin->intrinsic == nir_intrinsic_copy_deref || |
| intrin->intrinsic == nir_intrinsic_store_deref) || |
| nir_src_as_deref(intrin->src[0])->modes != 0) |
| return false; |
| } else { |
| return false; |
| } |
| |
| nir_instr_remove(instr); |
| return true; |
| } |
| |
| static bool |
| remove_dead_vars(struct exec_list *var_list, nir_variable_mode modes, |
| struct set *live, const nir_remove_dead_variables_options *opts) |
| { |
| bool progress = false; |
| |
| nir_foreach_variable_in_list_safe(var, var_list) { |
| if (!(var->data.mode & modes)) |
| continue; |
| |
| if (opts && opts->can_remove_var && |
| !opts->can_remove_var(var, opts->can_remove_var_data)) |
| continue; |
| |
| struct set_entry *entry = _mesa_set_search(live, var); |
| if (entry == NULL) { |
| /* Mark this variable as dead by setting the mode to 0 */ |
| var->data.mode = 0; |
| exec_node_remove(&var->node); |
| progress = true; |
| } |
| } |
| |
| return progress; |
| } |
| |
| bool |
| nir_remove_dead_variables(nir_shader *shader, nir_variable_mode modes, |
| const nir_remove_dead_variables_options *opts) |
| { |
| bool progress = false; |
| struct set *live = _mesa_pointer_set_create(NULL); |
| |
| add_var_use_shader(shader, live, modes); |
| |
| if (modes & ~nir_var_function_temp) { |
| progress = remove_dead_vars(&shader->variables, modes, |
| live, opts) || |
| progress; |
| } |
| |
| if (modes & nir_var_function_temp) { |
| nir_foreach_function_impl(impl, shader) { |
| if (remove_dead_vars(&impl->locals, |
| nir_var_function_temp, |
| live, opts)) |
| progress = true; |
| } |
| } |
| |
| _mesa_set_destroy(live, NULL); |
| |
| if (progress) { |
| nir_shader_instructions_pass(shader, remove_dead_var_writes, |
| nir_metadata_control_flow, NULL); |
| } else { |
| nir_shader_preserve_all_metadata(shader); |
| } |
| |
| return progress; |
| } |
