#include "nir.h"
-static void
-add_var_use_intrinsic(nir_intrinsic_instr *instr, struct set *live)
+static bool
+deref_used_for_not_store(nir_deref_instr *deref)
{
- 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);
- }
-}
+ nir_foreach_use(src, &deref->dest.ssa) {
+ switch (src->parent_instr->type) {
+ case nir_instr_type_deref:
+ if (deref_used_for_not_store(nir_instr_as_deref(src->parent_instr)))
+ return true;
+ break;
-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);
- }
+ case nir_instr_type_intrinsic: {
+ nir_intrinsic_instr *intrin =
+ nir_instr_as_intrinsic(src->parent_instr);
+ /* 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;
+ }
- for (unsigned i = 0; i < instr->num_params; i++) {
- nir_variable *var = instr->params[i]->var;
- _mesa_set_add(live, var);
+ 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_tex(nir_tex_instr *instr, struct set *live)
+add_var_use_deref(nir_deref_instr *deref, struct set *live)
{
- if (instr->texture != NULL) {
- nir_variable *var = instr->texture->var;
- _mesa_set_add(live, var);
- }
-
- if (instr->sampler != NULL) {
- nir_variable *var = instr->sampler->var;
- _mesa_set_add(live, var);
- }
+ if (deref->deref_type != nir_deref_type_var)
+ return;
+
+ /* If it's not a local that never escapes the shader, then any access at
+ * all means we need to keep it alive.
+ */
+ assert(deref->mode == deref->var->data.mode);
+ if (!(deref->mode & (nir_var_function_temp | nir_var_shader_temp | nir_var_mem_shared)) ||
+ deref_used_for_not_store(deref))
+ _mesa_set_add(live, deref->var);
}
-static bool
-add_var_use_block(nir_block *block, void *state)
+static void
+add_var_use_shader(nir_shader *shader, struct set *live, nir_variable_mode modes)
{
- 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;
+ nir_foreach_function(function, shader) {
+ if (function->impl) {
+ nir_foreach_block(block, function->impl) {
+ nir_foreach_instr(instr, block) {
+ if (instr->type == nir_instr_type_deref)
+ add_var_use_deref(nir_instr_as_deref(instr), live);
+ }
+ }
}
}
-
- return true;
}
static void
-add_var_use_shader(nir_shader *shader, struct set *live)
+remove_dead_var_writes(nir_shader *shader, struct set *live)
{
- nir_foreach_function(shader, function) {
- if (function->impl) {
- nir_foreach_block(function->impl, add_var_use_block, live);
+ nir_foreach_function(function, shader) {
+ if (!function->impl)
+ continue;
+
+ nir_foreach_block(block, function->impl) {
+ nir_foreach_instr_safe(instr, block) {
+ switch (instr->type) {
+ case 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))
+ continue;
+
+ nir_variable_mode parent_mode;
+ if (deref->deref_type == nir_deref_type_var)
+ parent_mode = deref->var->data.mode;
+ else
+ parent_mode = nir_deref_instr_parent(deref)->mode;
+
+ /* If the parent mode is 0, then it references a dead variable.
+ * Flag this deref as dead and remove it.
+ */
+ if (parent_mode == 0) {
+ deref->mode = 0;
+ nir_instr_remove(&deref->instr);
+ }
+ break;
+ }
+
+ case 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)
+ break;
+
+ if (nir_src_as_deref(intrin->src[0])->mode == 0)
+ nir_instr_remove(instr);
+ break;
+ }
+
+ default:
+ break; /* Nothing to do */
+ }
+ }
}
}
}
static bool
-remove_dead_vars(struct exec_list *var_list, struct set *live)
+remove_dead_vars(struct exec_list *var_list, nir_variable_mode modes,
+ struct set *live, bool (*can_remove_var)(nir_variable *var))
{
bool progress = false;
- foreach_list_typed_safe(nir_variable, var, node, var_list) {
+ nir_foreach_variable_in_list_safe(var, var_list) {
+ if (!(var->data.mode & modes))
+ continue;
+
+ if (can_remove_var && !can_remove_var(var))
+ continue;
+
struct set_entry *entry = _mesa_set_search(live, var);
if (entry == NULL) {
+ /* Mark this variable as used by setting the mode to 0 */
+ var->data.mode = 0;
exec_node_remove(&var->node);
- ralloc_free(var);
progress = true;
}
}
}
bool
-nir_remove_dead_variables(nir_shader *shader)
+nir_remove_dead_variables(nir_shader *shader, nir_variable_mode modes,
+ bool (*can_remove_var)(nir_variable *var))
{
bool progress = false;
- struct set *live =
- _mesa_set_create(NULL, _mesa_hash_pointer, _mesa_key_pointer_equal);
+ struct set *live = _mesa_pointer_set_create(NULL);
- add_var_use_shader(shader, live);
+ add_var_use_shader(shader, live, modes);
- progress = remove_dead_vars(&shader->globals, live) || progress;
+ if (modes & ~nir_var_function_temp) {
+ progress = remove_dead_vars(&shader->variables, modes,
+ live, can_remove_var) || 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;
+ if (modes & nir_var_function_temp) {
+ nir_foreach_function(function, shader) {
+ if (function->impl) {
+ if (remove_dead_vars(&function->impl->locals,
+ nir_var_function_temp,
+ live, can_remove_var))
+ progress = true;
}
}
}
+ nir_foreach_function(function, shader) {
+ if (!function->impl)
+ continue;
+
+ if (progress) {
+ remove_dead_var_writes(shader, live);
+ nir_metadata_preserve(function->impl, nir_metadata_block_index |
+ nir_metadata_dominance);
+ } else {
+ nir_metadata_preserve(function->impl, nir_metadata_all);
+ }
+ }
+
_mesa_set_destroy(live, NULL);
return progress;
}
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