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/*
* 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"
static void
add_var_use_intrinsic(nir_intrinsic_instr *instr, struct set *live)
{
unsigned num_vars = nir_intrinsic_infos[instr->intrinsic].num_variables;
for (unsigned i = 0; i < num_vars; i++) {
nir_variable *var = instr->variables[i]->var;
_mesa_set_add(live, var);
}
}
static void
add_var_use_call(nir_call_instr *instr, struct set *live)
{
if (instr->return_deref != NULL) {
nir_variable *var = instr->return_deref->var;
_mesa_set_add(live, var);
}
for (unsigned i = 0; i < instr->num_params; i++) {
nir_variable *var = instr->params[i]->var;
_mesa_set_add(live, var);
}
}
static void
add_var_use_tex(nir_tex_instr *instr, struct set *live)
{
if (instr->sampler != NULL) {
nir_variable *var = instr->sampler->var;
_mesa_set_add(live, var);
}
}
static bool
add_var_use_block(nir_block *block, void *state)
{
struct set *live = state;
nir_foreach_instr(block, instr) {
switch(instr->type) {
case nir_instr_type_intrinsic:
add_var_use_intrinsic(nir_instr_as_intrinsic(instr), live);
break;
case nir_instr_type_call:
add_var_use_call(nir_instr_as_call(instr), live);
break;
case nir_instr_type_tex:
add_var_use_tex(nir_instr_as_tex(instr), live);
break;
default:
break;
}
}
return true;
}
static void
add_var_use_shader(nir_shader *shader, struct set *live)
{
nir_foreach_function(shader, function) {
if (function->impl) {
nir_foreach_block(function->impl, add_var_use_block, live);
}
}
}
static bool
remove_dead_vars(struct exec_list *var_list, struct set *live)
{
bool progress = false;
foreach_list_typed_safe(nir_variable, var, node, var_list) {
struct set_entry *entry = _mesa_set_search(live, var);
if (entry == NULL) {
exec_node_remove(&var->node);
ralloc_free(var);
progress = true;
}
}
return progress;
}
bool
nir_remove_dead_variables(nir_shader *shader)
{
bool progress = false;
struct set *live =
_mesa_set_create(NULL, _mesa_hash_pointer, _mesa_key_pointer_equal);
add_var_use_shader(shader, live);
progress = remove_dead_vars(&shader->globals, live) || progress;
nir_foreach_function(shader, function) {
if (function->impl) {
if (remove_dead_vars(&function->impl->locals, live)) {
nir_metadata_preserve(function->impl, nir_metadata_block_index |
nir_metadata_dominance |
nir_metadata_live_ssa_defs);
progress = true;
}
}
}
_mesa_set_destroy(live, NULL);
return progress;
}
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