From: Jason Ekstrand Date: Wed, 14 Jan 2015 20:41:15 +0000 (-0800) Subject: nir: Rename lower_variables to lower_vars_to_ssa X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=55b5058e69859ba28c2f32de6edf5f0df3c6c28c;p=mesa.git nir: Rename lower_variables to lower_vars_to_ssa The original name wasn't particularly descriptive. This one indicates that it actually gives you SSA values as opposed to the old pass which lowered variables to registers. Reviewed-by: Connor Abbott --- diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources index a61f234bd4a..4c9aa77ceb6 100644 --- a/src/glsl/Makefile.sources +++ b/src/glsl/Makefile.sources @@ -31,7 +31,7 @@ NIR_FILES = \ $(GLSL_SRCDIR)/nir/nir_lower_samplers.cpp \ $(GLSL_SRCDIR)/nir/nir_lower_system_values.c \ $(GLSL_SRCDIR)/nir/nir_lower_to_source_mods.c \ - $(GLSL_SRCDIR)/nir/nir_lower_variables.c \ + $(GLSL_SRCDIR)/nir/nir_lower_vars_to_ssa.c \ $(GLSL_SRCDIR)/nir/nir_lower_vec_to_movs.c \ $(GLSL_SRCDIR)/nir/nir_metadata.c \ $(GLSL_SRCDIR)/nir/nir_opcodes.c \ diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h index e797ce24978..12cac728cff 100644 --- a/src/glsl/nir/nir.h +++ b/src/glsl/nir/nir.h @@ -1467,7 +1467,7 @@ void nir_lower_locals_to_regs(nir_shader *shader); void nir_lower_io(nir_shader *shader); -void nir_lower_variables(nir_shader *shader); +void nir_lower_vars_to_ssa(nir_shader *shader); void nir_remove_dead_variables(nir_shader *shader); diff --git a/src/glsl/nir/nir_lower_variables.c b/src/glsl/nir/nir_lower_variables.c deleted file mode 100644 index 4844b7c6ed0..00000000000 --- a/src/glsl/nir/nir_lower_variables.c +++ /dev/null @@ -1,1215 +0,0 @@ -/* - * 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: - * Jason Ekstrand (jason@jlekstrand.net) - * - */ - -#include "nir.h" - -struct deref_node { - struct deref_node *parent; - const struct glsl_type *type; - - bool lower_to_ssa; - - struct set *loads; - struct set *stores; - struct set *copies; - - nir_ssa_def **def_stack; - nir_ssa_def **def_stack_tail; - - struct deref_node *wildcard; - struct deref_node *indirect; - struct deref_node *children[0]; -}; - -struct lower_variables_state { - void *mem_ctx; - void *dead_ctx; - nir_function_impl *impl; - - /* A hash table mapping variables to deref_node data */ - struct hash_table *deref_var_nodes; - - /* A hash table mapping fully-qualified direct dereferences, i.e. - * dereferences with no indirect or wildcard array dereferences, to - * deref_node data. - * - * At the moment, we only lower loads, stores, and copies that can be - * trivially lowered to loads and stores, i.e. copies with no indirects - * and no wildcards. If a part of a variable that is being loaded from - * and/or stored into is also involved in a copy operation with - * wildcards, then we lower that copy operation to loads and stores, but - * otherwise we leave copies with wildcards alone. Since the only derefs - * used in these loads, stores, and trivial copies are ones with no - * wildcards and no indirects, these are precisely the derefs that we - * can actually consider lowering. - */ - struct hash_table *direct_deref_nodes; - - /* A hash table mapping phi nodes to deref_state data */ - struct hash_table *phi_table; -}; - -/* The following two functions implement a hash and equality check for - * variable dreferences. When the hash or equality function encounters an - * array, all indirects are treated as equal and are never equal to a - * direct dereference or a wildcard. - */ -static uint32_t -hash_deref(const void *void_deref) -{ - uint32_t hash = _mesa_fnv32_1a_offset_bias; - - const nir_deref_var *deref_var = void_deref; - hash = _mesa_fnv32_1a_accumulate(hash, deref_var->var); - - for (const nir_deref *deref = deref_var->deref.child; - deref; deref = deref->child) { - switch (deref->deref_type) { - case nir_deref_type_array: { - nir_deref_array *deref_array = nir_deref_as_array(deref); - - hash = _mesa_fnv32_1a_accumulate(hash, deref_array->deref_array_type); - - if (deref_array->deref_array_type == nir_deref_array_type_direct) - hash = _mesa_fnv32_1a_accumulate(hash, deref_array->base_offset); - break; - } - case nir_deref_type_struct: { - nir_deref_struct *deref_struct = nir_deref_as_struct(deref); - hash = _mesa_fnv32_1a_accumulate(hash, deref_struct->index); - break; - } - default: - assert("Invalid deref chain"); - } - } - - return hash; -} - -static bool -derefs_equal(const void *void_a, const void *void_b) -{ - const nir_deref_var *a_var = void_a; - const nir_deref_var *b_var = void_b; - - if (a_var->var != b_var->var) - return false; - - for (const nir_deref *a = a_var->deref.child, *b = b_var->deref.child; - a != NULL; a = a->child, b = b->child) { - if (a->deref_type != b->deref_type) - return false; - - switch (a->deref_type) { - case nir_deref_type_array: { - nir_deref_array *a_arr = nir_deref_as_array(a); - nir_deref_array *b_arr = nir_deref_as_array(b); - - if (a_arr->deref_array_type != b_arr->deref_array_type) - return false; - - if (a_arr->deref_array_type == nir_deref_array_type_direct && - a_arr->base_offset != b_arr->base_offset) - return false; - break; - } - case nir_deref_type_struct: - if (nir_deref_as_struct(a)->index != nir_deref_as_struct(b)->index) - return false; - break; - default: - assert("Invalid deref chain"); - return false; - } - - assert((a->child == NULL) == (b->child == NULL)); - if((a->child == NULL) != (b->child == NULL)) - return false; - } - - return true; -} - -static int -type_get_length(const struct glsl_type *type) -{ - switch (glsl_get_base_type(type)) { - case GLSL_TYPE_STRUCT: - case GLSL_TYPE_ARRAY: - return glsl_get_length(type); - case GLSL_TYPE_FLOAT: - case GLSL_TYPE_INT: - case GLSL_TYPE_UINT: - case GLSL_TYPE_BOOL: - if (glsl_type_is_matrix(type)) - return glsl_get_matrix_columns(type); - else - return glsl_get_vector_elements(type); - default: - unreachable("Invalid deref base type"); - } -} - -static struct deref_node * -deref_node_create(struct deref_node *parent, - const struct glsl_type *type, void *mem_ctx) -{ - size_t size = sizeof(struct deref_node) + - type_get_length(type) * sizeof(struct deref_node *); - - struct deref_node *node = rzalloc_size(mem_ctx, size); - node->type = type; - node->parent = parent; - - return node; -} - -/* Gets the deref_node for the given deref chain and creates it if it - * doesn't yet exist. If the deref is fully-qualified and direct and - * add_to_direct_deref_nodes is true, it will be added to the hash table of - * of fully-qualified direct derefs. - */ -static struct deref_node * -get_deref_node(nir_deref_var *deref, bool add_to_direct_deref_nodes, - struct lower_variables_state *state) -{ - bool is_direct = true; - - struct deref_node *node; - - struct hash_entry *var_entry = - _mesa_hash_table_search(state->deref_var_nodes, deref->var); - - if (var_entry) { - node = var_entry->data; - } else { - node = deref_node_create(NULL, deref->deref.type, state->dead_ctx); - _mesa_hash_table_insert(state->deref_var_nodes, deref->var, node); - } - - for (nir_deref *tail = deref->deref.child; tail; tail = tail->child) { - switch (tail->deref_type) { - case nir_deref_type_struct: { - nir_deref_struct *deref_struct = nir_deref_as_struct(tail); - - assert(deref_struct->index < type_get_length(node->type)); - - if (node->children[deref_struct->index] == NULL) - node->children[deref_struct->index] = - deref_node_create(node, tail->type, state->dead_ctx); - - node = node->children[deref_struct->index]; - break; - } - - case nir_deref_type_array: { - nir_deref_array *arr = nir_deref_as_array(tail); - - switch (arr->deref_array_type) { - case nir_deref_array_type_direct: - /* This is possible if a loop unrolls and generates an - * out-of-bounds offset. We need to handle this at least - * somewhat gracefully. - */ - if (arr->base_offset >= type_get_length(node->type)) - return NULL; - - if (node->children[arr->base_offset] == NULL) - node->children[arr->base_offset] = - deref_node_create(node, tail->type, state->dead_ctx); - - node = node->children[arr->base_offset]; - break; - - case nir_deref_array_type_indirect: - if (node->indirect == NULL) - node->indirect = deref_node_create(node, tail->type, - state->dead_ctx); - - node = node->indirect; - is_direct = false; - break; - - case nir_deref_array_type_wildcard: - if (node->wildcard == NULL) - node->wildcard = deref_node_create(node, tail->type, - state->dead_ctx); - - node = node->wildcard; - is_direct = false; - break; - - default: - unreachable("Invalid array deref type"); - } - break; - } - default: - unreachable("Invalid deref type"); - } - } - - assert(node); - - if (is_direct && add_to_direct_deref_nodes) - _mesa_hash_table_insert(state->direct_deref_nodes, deref, node); - - return node; -} - -/* \sa foreach_deref_node_match */ -static bool -foreach_deref_node_worker(struct deref_node *node, nir_deref *deref, - bool (* cb)(struct deref_node *node, - struct lower_variables_state *state), - struct lower_variables_state *state) -{ - if (deref->child == NULL) { - return cb(node, state); - } else { - switch (deref->child->deref_type) { - case nir_deref_type_array: { - nir_deref_array *arr = nir_deref_as_array(deref->child); - assert(arr->deref_array_type == nir_deref_array_type_direct); - if (node->children[arr->base_offset] && - !foreach_deref_node_worker(node->children[arr->base_offset], - deref->child, cb, state)) - return false; - - if (node->wildcard && - !foreach_deref_node_worker(node->wildcard, - deref->child, cb, state)) - return false; - - return true; - } - - case nir_deref_type_struct: { - nir_deref_struct *str = nir_deref_as_struct(deref->child); - return foreach_deref_node_worker(node->children[str->index], - deref->child, cb, state); - } - - default: - unreachable("Invalid deref child type"); - } - } -} - -/* Walks over every "matching" deref_node and calls the callback. A node - * is considered to "match" if either refers to that deref or matches up t - * a wildcard. In other words, the following would match a[6].foo[3].bar: - * - * a[6].foo[3].bar - * a[*].foo[3].bar - * a[6].foo[*].bar - * a[*].foo[*].bar - * - * The given deref must be a full-length and fully qualified (no wildcards - * or indirects) deref chain. - */ -static bool -foreach_deref_node_match(nir_deref_var *deref, - bool (* cb)(struct deref_node *node, - struct lower_variables_state *state), - struct lower_variables_state *state) -{ - nir_deref_var var_deref = *deref; - var_deref.deref.child = NULL; - struct deref_node *node = get_deref_node(&var_deref, false, state); - - if (node == NULL) - return false; - - return foreach_deref_node_worker(node, &deref->deref, cb, state); -} - -/* \sa deref_may_be_aliased */ -static bool -deref_may_be_aliased_node(struct deref_node *node, nir_deref *deref, - struct lower_variables_state *state) -{ - if (deref->child == NULL) { - return false; - } else { - switch (deref->child->deref_type) { - case nir_deref_type_array: { - nir_deref_array *arr = nir_deref_as_array(deref->child); - if (arr->deref_array_type == nir_deref_array_type_indirect) - return true; - - assert(arr->deref_array_type == nir_deref_array_type_direct); - - if (node->children[arr->base_offset] && - deref_may_be_aliased_node(node->children[arr->base_offset], - deref->child, state)) - return true; - - if (node->wildcard && - deref_may_be_aliased_node(node->wildcard, deref->child, state)) - return true; - - return false; - } - - case nir_deref_type_struct: { - nir_deref_struct *str = nir_deref_as_struct(deref->child); - if (node->children[str->index]) { - return deref_may_be_aliased_node(node->children[str->index], - deref->child, state); - } else { - return false; - } - } - - default: - unreachable("Invalid nir_deref child type"); - } - } -} - -/* Returns true if there are no indirects that can ever touch this deref. - * - * For example, if the given deref is a[6].foo, then any uses of a[i].foo - * would cause this to return false, but a[i].bar would not affect it - * because it's a different structure member. A var_copy involving of - * a[*].bar also doesn't affect it because that can be lowered to entirely - * direct load/stores. - * - * We only support asking this question about fully-qualified derefs. - * Obviously, it's pointless to ask this about indirects, but we also - * rule-out wildcards. Handling Wildcard dereferences would involve - * checking each array index to make sure that there aren't any indirect - * references. - */ -static bool -deref_may_be_aliased(nir_deref_var *deref, - struct lower_variables_state *state) -{ - nir_deref_var var_deref = *deref; - var_deref.deref.child = NULL; - struct deref_node *node = get_deref_node(&var_deref, false, state); - - /* An invalid dereference can't be aliased. */ - if (node == NULL) - return false; - - return deref_may_be_aliased_node(node, &deref->deref, state); -} - -static void -register_load_instr(nir_intrinsic_instr *load_instr, bool create_node, - struct lower_variables_state *state) -{ - struct deref_node *node = get_deref_node(load_instr->variables[0], - create_node, state); - if (node == NULL) - return; - - if (node->loads == NULL) - node->loads = _mesa_set_create(state->dead_ctx, - _mesa_key_pointer_equal); - - _mesa_set_add(node->loads, _mesa_hash_pointer(load_instr), load_instr); -} - -static void -register_store_instr(nir_intrinsic_instr *store_instr, bool create_node, - struct lower_variables_state *state) -{ - struct deref_node *node = get_deref_node(store_instr->variables[0], - create_node, state); - if (node == NULL) - return; - - if (node->stores == NULL) - node->stores = _mesa_set_create(state->dead_ctx, - _mesa_key_pointer_equal); - - _mesa_set_add(node->stores, _mesa_hash_pointer(store_instr), store_instr); -} - -static void -register_copy_instr(nir_intrinsic_instr *copy_instr, bool create_node, - struct lower_variables_state *state) -{ - for (unsigned idx = 0; idx < 2; idx++) { - struct deref_node *node = get_deref_node(copy_instr->variables[idx], - create_node, state); - if (node == NULL) - continue; - - if (node->copies == NULL) - node->copies = _mesa_set_create(state->dead_ctx, - _mesa_key_pointer_equal); - - _mesa_set_add(node->copies, _mesa_hash_pointer(copy_instr), copy_instr); - } -} - -/* Registers all variable uses in the given block. */ -static bool -register_variable_uses_block(nir_block *block, void *void_state) -{ - struct lower_variables_state *state = void_state; - - nir_foreach_instr_safe(block, instr) { - if (instr->type != nir_instr_type_intrinsic) - continue; - - nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); - - switch (intrin->intrinsic) { - case nir_intrinsic_load_var: - register_load_instr(intrin, true, state); - break; - - case nir_intrinsic_store_var: - register_store_instr(intrin, true, state); - break; - - case nir_intrinsic_copy_var: - register_copy_instr(intrin, true, state); - break; - - default: - continue; - } - } - - return true; -} - -/* Walks down the deref chain and returns the next deref in the chain whose - * child is a wildcard. In other words, given the chain a[1].foo[*].bar, - * this function will return the deref to foo. Calling it a second time - * with the [*].bar, it will return NULL. - */ -static nir_deref * -deref_next_wildcard_parent(nir_deref *deref) -{ - for (nir_deref *tail = deref; tail->child; tail = tail->child) { - if (tail->child->deref_type != nir_deref_type_array) - continue; - - nir_deref_array *arr = nir_deref_as_array(tail->child); - - if (arr->deref_array_type == nir_deref_array_type_wildcard) - return tail; - } - - return NULL; -} - -/* Returns the last deref in the chain. - */ -static nir_deref * -get_deref_tail(nir_deref *deref) -{ - while (deref->child) - deref = deref->child; - - return deref; -} - -/* This function recursively walks the given deref chain and replaces the - * given copy instruction with an equivalent sequence load/store - * operations. - * - * @copy_instr The copy instruction to replace; new instructions will be - * inserted before this one - * - * @dest_head The head of the destination variable deref chain - * - * @src_head The head of the source variable deref chain - * - * @dest_tail The current tail of the destination variable deref chain; - * this is used for recursion and external callers of this - * function should call it with tail == head - * - * @src_tail The current tail of the source variable deref chain; - * this is used for recursion and external callers of this - * function should call it with tail == head - * - * @state The current variable lowering state - */ -static void -emit_copy_load_store(nir_intrinsic_instr *copy_instr, - nir_deref_var *dest_head, nir_deref_var *src_head, - nir_deref *dest_tail, nir_deref *src_tail, - struct lower_variables_state *state) -{ - /* Find the next pair of wildcards */ - nir_deref *src_arr_parent = deref_next_wildcard_parent(src_tail); - nir_deref *dest_arr_parent = deref_next_wildcard_parent(dest_tail); - - if (src_arr_parent || dest_arr_parent) { - /* Wildcards had better come in matched pairs */ - assert(dest_arr_parent && dest_arr_parent); - - nir_deref_array *src_arr = nir_deref_as_array(src_arr_parent->child); - nir_deref_array *dest_arr = nir_deref_as_array(dest_arr_parent->child); - - unsigned length = type_get_length(src_arr_parent->type); - /* The wildcards should represent the same number of elements */ - assert(length == type_get_length(dest_arr_parent->type)); - assert(length > 0); - - /* Walk over all of the elements that this wildcard refers to and - * call emit_copy_load_store on each one of them */ - src_arr->deref_array_type = nir_deref_array_type_direct; - dest_arr->deref_array_type = nir_deref_array_type_direct; - for (unsigned i = 0; i < length; i++) { - src_arr->base_offset = i; - dest_arr->base_offset = i; - emit_copy_load_store(copy_instr, dest_head, src_head, - &dest_arr->deref, &src_arr->deref, state); - } - src_arr->deref_array_type = nir_deref_array_type_wildcard; - dest_arr->deref_array_type = nir_deref_array_type_wildcard; - } else { - /* In this case, we have no wildcards anymore, so all we have to do - * is just emit the load and store operations. */ - src_tail = get_deref_tail(src_tail); - dest_tail = get_deref_tail(dest_tail); - - assert(src_tail->type == dest_tail->type); - - unsigned num_components = glsl_get_vector_elements(src_tail->type); - - nir_deref *src_deref = nir_copy_deref(state->mem_ctx, &src_head->deref); - nir_deref *dest_deref = nir_copy_deref(state->mem_ctx, &dest_head->deref); - - nir_intrinsic_instr *load = - nir_intrinsic_instr_create(state->mem_ctx, nir_intrinsic_load_var); - load->num_components = num_components; - load->variables[0] = nir_deref_as_var(src_deref); - load->dest.is_ssa = true; - nir_ssa_def_init(&load->instr, &load->dest.ssa, num_components, NULL); - - nir_instr_insert_before(©_instr->instr, &load->instr); - register_load_instr(load, false, state); - - nir_intrinsic_instr *store = - nir_intrinsic_instr_create(state->mem_ctx, nir_intrinsic_store_var); - store->num_components = num_components; - store->variables[0] = nir_deref_as_var(dest_deref); - store->src[0].is_ssa = true; - store->src[0].ssa = &load->dest.ssa; - - nir_instr_insert_before(©_instr->instr, &store->instr); - register_store_instr(store, false, state); - } -} - -/* Walks over all of the copy instructions to or from the given deref_node - * and lowers them to load/store intrinsics. - */ -static bool -lower_copies_to_load_store(struct deref_node *node, - struct lower_variables_state *state) -{ - if (!node->copies) - return true; - - struct set_entry *copy_entry; - set_foreach(node->copies, copy_entry) { - nir_intrinsic_instr *copy = (void *)copy_entry->key; - - emit_copy_load_store(copy, copy->variables[0], copy->variables[1], - ©->variables[0]->deref, - ©->variables[1]->deref, - state); - - for (unsigned i = 0; i < 2; ++i) { - struct deref_node *arg_node = get_deref_node(copy->variables[i], - false, state); - if (arg_node == NULL) - continue; - - struct set_entry *arg_entry = _mesa_set_search(arg_node->copies, - copy_entry->hash, - copy); - assert(arg_entry); - _mesa_set_remove(node->copies, arg_entry); - } - - nir_instr_remove(©->instr); - } - - return true; -} - -/* Returns a load_const instruction that represents the constant - * initializer for the given deref chain. The caller is responsible for - * ensuring that there actually is a constant initializer. - */ -static nir_load_const_instr * -get_const_initializer_load(const nir_deref_var *deref, - struct lower_variables_state *state) -{ - nir_constant *constant = deref->var->constant_initializer; - const nir_deref *tail = &deref->deref; - unsigned matrix_offset = 0; - while (tail->child) { - switch (tail->child->deref_type) { - case nir_deref_type_array: { - nir_deref_array *arr = nir_deref_as_array(tail->child); - assert(arr->deref_array_type == nir_deref_array_type_direct); - if (glsl_type_is_matrix(tail->type)) { - assert(arr->deref.child == NULL); - matrix_offset = arr->base_offset; - } else { - constant = constant->elements[arr->base_offset]; - } - break; - } - - case nir_deref_type_struct: { - constant = constant->elements[nir_deref_as_struct(tail->child)->index]; - break; - } - - default: - unreachable("Invalid deref child type"); - } - - tail = tail->child; - } - - nir_load_const_instr *load = - nir_load_const_instr_create(state->mem_ctx, - glsl_get_vector_elements(tail->type)); - - matrix_offset *= load->def.num_components; - for (unsigned i = 0; i < load->def.num_components; i++) { - switch (glsl_get_base_type(tail->type)) { - case GLSL_TYPE_FLOAT: - case GLSL_TYPE_INT: - case GLSL_TYPE_UINT: - load->value.u[i] = constant->value.u[matrix_offset + i]; - break; - case GLSL_TYPE_BOOL: - load->value.u[i] = constant->value.u[matrix_offset + i] ? - NIR_TRUE : NIR_FALSE; - break; - default: - unreachable("Invalid immediate type"); - } - } - - return load; -} - -/** Pushes an SSA def onto the def stack for the given node - * - * Each node is potentially associated with a stack of SSA definitions. - * This stack is used for determining what SSA definition reaches a given - * point in the program for variable renaming. The stack is always kept in - * dominance-order with at most one SSA def per block. If the SSA - * definition on the top of the stack is in the same block as the one being - * pushed, the top element is replaced. - */ -static void -def_stack_push(struct deref_node *node, nir_ssa_def *def, - struct lower_variables_state *state) -{ - if (node->def_stack == NULL) { - node->def_stack = ralloc_array(state->dead_ctx, nir_ssa_def *, - state->impl->num_blocks); - node->def_stack_tail = node->def_stack - 1; - } - - if (node->def_stack_tail >= node->def_stack) { - nir_ssa_def *top_def = *node->def_stack_tail; - - if (def->parent_instr->block == top_def->parent_instr->block) { - /* They're in the same block, just replace the top */ - *node->def_stack_tail = def; - return; - } - } - - *(++node->def_stack_tail) = def; -} - -/* Pop the top of the def stack if it's in the given block */ -static void -def_stack_pop_if_in_block(struct deref_node *node, nir_block *block) -{ - /* If we're popping, then we have presumably pushed at some time in the - * past so this should exist. - */ - assert(node->def_stack != NULL); - - /* The stack is already empty. Do nothing. */ - if (node->def_stack_tail < node->def_stack) - return; - - nir_ssa_def *def = *node->def_stack_tail; - if (def->parent_instr->block == block) - node->def_stack_tail--; -} - -/** Retrieves the SSA definition on the top of the stack for the given - * node, if one exists. If the stack is empty, then we return the constant - * initializer (if it exists) or an SSA undef. - */ -static nir_ssa_def * -get_ssa_def_for_block(struct deref_node *node, nir_block *block, - struct lower_variables_state *state) -{ - /* If we have something on the stack, go ahead and return it. We're - * assuming that the top of the stack dominates the given block. - */ - if (node->def_stack && node->def_stack_tail >= node->def_stack) - return *node->def_stack_tail; - - /* If we got here then we don't have a definition that dominates the - * given block. This means that we need to add an undef and use that. - */ - nir_ssa_undef_instr *undef = - nir_ssa_undef_instr_create(state->mem_ctx, - glsl_get_vector_elements(node->type)); - nir_instr_insert_before_cf_list(&state->impl->body, &undef->instr); - def_stack_push(node, &undef->def, state); - return &undef->def; -} - -/* Given a block and one of its predecessors, this function fills in the - * souces of the phi nodes to take SSA defs from the given predecessor. - * This function must be called exactly once per block/predecessor pair. - */ -static void -add_phi_sources(nir_block *block, nir_block *pred, - struct lower_variables_state *state) -{ - nir_foreach_instr(block, instr) { - if (instr->type != nir_instr_type_phi) - break; - - nir_phi_instr *phi = nir_instr_as_phi(instr); - - struct hash_entry *entry = - _mesa_hash_table_search(state->phi_table, phi); - if (!entry) - continue; - - struct deref_node *node = entry->data; - - nir_phi_src *src = ralloc(state->mem_ctx, nir_phi_src); - src->pred = pred; - src->src.is_ssa = true; - src->src.ssa = get_ssa_def_for_block(node, pred, state); - - _mesa_set_add(src->src.ssa->uses, _mesa_hash_pointer(instr), instr); - - exec_list_push_tail(&phi->srcs, &src->node); - } -} - -/* Performs variable renaming by doing a DFS of the dominance tree - * - * This algorithm is very similar to the one outlined in "Efficiently - * Computing Static Single Assignment Form and the Control Dependence - * Graph" by Cytron et. al. The primary difference is that we only put one - * SSA def on the stack per block. - */ -static bool -rename_variables_block(nir_block *block, struct lower_variables_state *state) -{ - nir_foreach_instr_safe(block, instr) { - if (instr->type == nir_instr_type_phi) { - nir_phi_instr *phi = nir_instr_as_phi(instr); - - struct hash_entry *entry = - _mesa_hash_table_search(state->phi_table, phi); - - /* This can happen if we already have phi nodes in the program - * that were not created in this pass. - */ - if (!entry) - continue; - - struct deref_node *node = entry->data; - - def_stack_push(node, &phi->dest.ssa, state); - } else if (instr->type == nir_instr_type_intrinsic) { - nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); - - switch (intrin->intrinsic) { - case nir_intrinsic_load_var: { - struct deref_node *node = get_deref_node(intrin->variables[0], - false, state); - - if (node == NULL) { - /* If we hit this path then we are referencing an invalid - * value. Most likely, we unrolled something and are - * reading past the end of some array. In any case, this - * should result in an undefined value. - */ - nir_ssa_undef_instr *undef = - nir_ssa_undef_instr_create(state->mem_ctx, - intrin->num_components); - - nir_instr_insert_before(&intrin->instr, &undef->instr); - nir_instr_remove(&intrin->instr); - - nir_src new_src = { - .is_ssa = true, - .ssa = &undef->def, - }; - - nir_ssa_def_rewrite_uses(&intrin->dest.ssa, new_src, - state->mem_ctx); - continue; - } - - if (!node->lower_to_ssa) - continue; - - nir_alu_instr *mov = nir_alu_instr_create(state->mem_ctx, - nir_op_imov); - mov->src[0].src.is_ssa = true; - mov->src[0].src.ssa = get_ssa_def_for_block(node, block, state); - for (unsigned i = intrin->num_components; i < 4; i++) - mov->src[0].swizzle[i] = 0; - - assert(intrin->dest.is_ssa); - - mov->dest.write_mask = (1 << intrin->num_components) - 1; - mov->dest.dest.is_ssa = true; - nir_ssa_def_init(&mov->instr, &mov->dest.dest.ssa, - intrin->num_components, NULL); - - nir_instr_insert_before(&intrin->instr, &mov->instr); - nir_instr_remove(&intrin->instr); - - nir_src new_src = { - .is_ssa = true, - .ssa = &mov->dest.dest.ssa, - }; - - nir_ssa_def_rewrite_uses(&intrin->dest.ssa, new_src, - state->mem_ctx); - break; - } - - case nir_intrinsic_store_var: { - struct deref_node *node = get_deref_node(intrin->variables[0], - false, state); - - if (node == NULL) { - /* Probably an out-of-bounds array store. That should be a - * no-op. */ - nir_instr_remove(&intrin->instr); - continue; - } - - if (!node->lower_to_ssa) - continue; - - assert(intrin->num_components == - glsl_get_vector_elements(node->type)); - - assert(intrin->src[0].is_ssa); - - nir_alu_instr *mov = nir_alu_instr_create(state->mem_ctx, - nir_op_imov); - mov->src[0].src.is_ssa = true; - mov->src[0].src.ssa = intrin->src[0].ssa; - for (unsigned i = intrin->num_components; i < 4; i++) - mov->src[0].swizzle[i] = 0; - - mov->dest.write_mask = (1 << intrin->num_components) - 1; - mov->dest.dest.is_ssa = true; - nir_ssa_def_init(&mov->instr, &mov->dest.dest.ssa, - intrin->num_components, NULL); - - nir_instr_insert_before(&intrin->instr, &mov->instr); - - def_stack_push(node, &mov->dest.dest.ssa, state); - - /* We'll wait to remove the instruction until the next pass - * where we pop the node we just pushed back off the stack. - */ - break; - } - - default: - break; - } - } - } - - if (block->successors[0]) - add_phi_sources(block->successors[0], block, state); - if (block->successors[1]) - add_phi_sources(block->successors[1], block, state); - - for (unsigned i = 0; i < block->num_dom_children; ++i) - rename_variables_block(block->dom_children[i], state); - - /* Now we iterate over the instructions and pop off any SSA defs that we - * pushed in the first loop. - */ - nir_foreach_instr_safe(block, instr) { - if (instr->type == nir_instr_type_phi) { - nir_phi_instr *phi = nir_instr_as_phi(instr); - - struct hash_entry *entry = - _mesa_hash_table_search(state->phi_table, phi); - - /* This can happen if we already have phi nodes in the program - * that were not created in this pass. - */ - if (!entry) - continue; - - struct deref_node *node = entry->data; - - def_stack_pop_if_in_block(node, block); - } else if (instr->type == nir_instr_type_intrinsic) { - nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); - - if (intrin->intrinsic != nir_intrinsic_store_var) - continue; - - struct deref_node *node = get_deref_node(intrin->variables[0], - false, state); - if (!node) - continue; - - if (!node->lower_to_ssa) - continue; - - def_stack_pop_if_in_block(node, block); - nir_instr_remove(&intrin->instr); - } - } - - return true; -} - -/* Inserts phi nodes for all variables marked lower_to_ssa - * - * This is the same algorithm as presented in "Efficiently Computing Static - * Single Assignment Form and the Control Dependence Graph" by Cytron et. - * al. - */ -static void -insert_phi_nodes(struct lower_variables_state *state) -{ - unsigned work[state->impl->num_blocks]; - unsigned has_already[state->impl->num_blocks]; - - /* - * Since the work flags already prevent us from inserting a node that has - * ever been inserted into W, we don't need to use a set to represent W. - * Also, since no block can ever be inserted into W more than once, we know - * that the maximum size of W is the number of basic blocks in the - * function. So all we need to handle W is an array and a pointer to the - * next element to be inserted and the next element to be removed. - */ - nir_block *W[state->impl->num_blocks]; - - memset(work, 0, sizeof work); - memset(has_already, 0, sizeof has_already); - - unsigned w_start, w_end; - unsigned iter_count = 0; - - struct hash_entry *deref_entry; - hash_table_foreach(state->direct_deref_nodes, deref_entry) { - struct deref_node *node = deref_entry->data; - - if (node->stores == NULL) - continue; - - if (!node->lower_to_ssa) - continue; - - w_start = w_end = 0; - iter_count++; - - struct set_entry *store_entry; - set_foreach(node->stores, store_entry) { - nir_intrinsic_instr *store = (nir_intrinsic_instr *)store_entry->key; - if (work[store->instr.block->index] < iter_count) - W[w_end++] = store->instr.block; - work[store->instr.block->index] = iter_count; - } - - while (w_start != w_end) { - nir_block *cur = W[w_start++]; - struct set_entry *dom_entry; - set_foreach(cur->dom_frontier, dom_entry) { - nir_block *next = (nir_block *) dom_entry->key; - - /* - * If there's more than one return statement, then the end block - * can be a join point for some definitions. However, there are - * no instructions in the end block, so nothing would use those - * phi nodes. Of course, we couldn't place those phi nodes - * anyways due to the restriction of having no instructions in the - * end block... - */ - if (next == state->impl->end_block) - continue; - - if (has_already[next->index] < iter_count) { - nir_phi_instr *phi = nir_phi_instr_create(state->mem_ctx); - phi->dest.is_ssa = true; - nir_ssa_def_init(&phi->instr, &phi->dest.ssa, - glsl_get_vector_elements(node->type), NULL); - nir_instr_insert_before_block(next, &phi->instr); - - _mesa_hash_table_insert(state->phi_table, phi, node); - - has_already[next->index] = iter_count; - if (work[next->index] < iter_count) { - work[next->index] = iter_count; - W[w_end++] = next; - } - } - } - } - } -} - - -/** Implements a pass to lower variable uses to SSA values - * - * This path walks the list of instructions and tries to lower as many - * local variable load/store operations to SSA defs and uses as it can. - * The process involves four passes: - * - * 1) Iterate over all of the instructions and mark where each local - * variable deref is used in a load, store, or copy. While we're at - * it, we keep track of all of the fully-qualified (no wildcards) and - * fully-direct references we see and store them in the - * direct_deref_nodes hash table. - * - * 2) Walk over the the list of fully-qualified direct derefs generated in - * the previous pass. For each deref, we determine if it can ever be - * aliased, i.e. if there is an indirect reference anywhere that may - * refer to it. If it cannot be aliased, we mark it for lowering to an - * SSA value. At this point, we lower any var_copy instructions that - * use the given deref to load/store operations and, if the deref has a - * constant initializer, we go ahead and add a load_const value at the - * beginning of the function with the initialized value. - * - * 3) Walk over the list of derefs we plan to lower to SSA values and - * insert phi nodes as needed. - * - * 4) Perform "variable renaming" by replacing the load/store instructions - * with SSA definitions and SSA uses. - */ -static bool -nir_lower_variables_impl(nir_function_impl *impl) -{ - struct lower_variables_state state; - - state.mem_ctx = ralloc_parent(impl); - state.dead_ctx = ralloc_context(state.mem_ctx); - state.impl = impl; - - state.deref_var_nodes = _mesa_hash_table_create(state.dead_ctx, - _mesa_hash_pointer, - _mesa_key_pointer_equal); - state.direct_deref_nodes = _mesa_hash_table_create(state.dead_ctx, - hash_deref, derefs_equal); - state.phi_table = _mesa_hash_table_create(state.dead_ctx, - _mesa_hash_pointer, - _mesa_key_pointer_equal); - - nir_foreach_block(impl, register_variable_uses_block, &state); - - struct set *outputs = _mesa_set_create(state.dead_ctx, - _mesa_key_pointer_equal); - - bool progress = false; - - nir_metadata_require(impl, nir_metadata_block_index); - - struct hash_entry *entry; - hash_table_foreach(state.direct_deref_nodes, entry) { - nir_deref_var *deref = (void *)entry->key; - struct deref_node *node = entry->data; - - if (deref->var->data.mode != nir_var_local) { - _mesa_hash_table_remove(state.direct_deref_nodes, entry); - continue; - } - - if (deref_may_be_aliased(deref, &state)) { - _mesa_hash_table_remove(state.direct_deref_nodes, entry); - continue; - } - - node->lower_to_ssa = true; - progress = true; - - if (deref->var->constant_initializer) { - nir_load_const_instr *load = get_const_initializer_load(deref, &state); - nir_ssa_def_init(&load->instr, &load->def, - glsl_get_vector_elements(node->type), NULL); - nir_instr_insert_before_cf_list(&impl->body, &load->instr); - def_stack_push(node, &load->def, &state); - } - - if (deref->var->data.mode == nir_var_shader_out) - _mesa_set_add(outputs, _mesa_hash_pointer(node), node); - - foreach_deref_node_match(deref, lower_copies_to_load_store, &state); - } - - if (!progress) - return false; - - nir_metadata_require(impl, nir_metadata_dominance); - - insert_phi_nodes(&state); - rename_variables_block(impl->start_block, &state); - - nir_metadata_preserve(impl, nir_metadata_block_index | - nir_metadata_dominance); - - ralloc_free(state.dead_ctx); - - return progress; -} - -void -nir_lower_variables(nir_shader *shader) -{ - nir_foreach_overload(shader, overload) { - if (overload->impl) - nir_lower_variables_impl(overload->impl); - } -} diff --git a/src/glsl/nir/nir_lower_vars_to_ssa.c b/src/glsl/nir/nir_lower_vars_to_ssa.c new file mode 100644 index 00000000000..2b40ededc7d --- /dev/null +++ b/src/glsl/nir/nir_lower_vars_to_ssa.c @@ -0,0 +1,1215 @@ +/* + * 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: + * Jason Ekstrand (jason@jlekstrand.net) + * + */ + +#include "nir.h" + +struct deref_node { + struct deref_node *parent; + const struct glsl_type *type; + + bool lower_to_ssa; + + struct set *loads; + struct set *stores; + struct set *copies; + + nir_ssa_def **def_stack; + nir_ssa_def **def_stack_tail; + + struct deref_node *wildcard; + struct deref_node *indirect; + struct deref_node *children[0]; +}; + +struct lower_variables_state { + void *mem_ctx; + void *dead_ctx; + nir_function_impl *impl; + + /* A hash table mapping variables to deref_node data */ + struct hash_table *deref_var_nodes; + + /* A hash table mapping fully-qualified direct dereferences, i.e. + * dereferences with no indirect or wildcard array dereferences, to + * deref_node data. + * + * At the moment, we only lower loads, stores, and copies that can be + * trivially lowered to loads and stores, i.e. copies with no indirects + * and no wildcards. If a part of a variable that is being loaded from + * and/or stored into is also involved in a copy operation with + * wildcards, then we lower that copy operation to loads and stores, but + * otherwise we leave copies with wildcards alone. Since the only derefs + * used in these loads, stores, and trivial copies are ones with no + * wildcards and no indirects, these are precisely the derefs that we + * can actually consider lowering. + */ + struct hash_table *direct_deref_nodes; + + /* A hash table mapping phi nodes to deref_state data */ + struct hash_table *phi_table; +}; + +/* The following two functions implement a hash and equality check for + * variable dreferences. When the hash or equality function encounters an + * array, all indirects are treated as equal and are never equal to a + * direct dereference or a wildcard. + */ +static uint32_t +hash_deref(const void *void_deref) +{ + uint32_t hash = _mesa_fnv32_1a_offset_bias; + + const nir_deref_var *deref_var = void_deref; + hash = _mesa_fnv32_1a_accumulate(hash, deref_var->var); + + for (const nir_deref *deref = deref_var->deref.child; + deref; deref = deref->child) { + switch (deref->deref_type) { + case nir_deref_type_array: { + nir_deref_array *deref_array = nir_deref_as_array(deref); + + hash = _mesa_fnv32_1a_accumulate(hash, deref_array->deref_array_type); + + if (deref_array->deref_array_type == nir_deref_array_type_direct) + hash = _mesa_fnv32_1a_accumulate(hash, deref_array->base_offset); + break; + } + case nir_deref_type_struct: { + nir_deref_struct *deref_struct = nir_deref_as_struct(deref); + hash = _mesa_fnv32_1a_accumulate(hash, deref_struct->index); + break; + } + default: + assert("Invalid deref chain"); + } + } + + return hash; +} + +static bool +derefs_equal(const void *void_a, const void *void_b) +{ + const nir_deref_var *a_var = void_a; + const nir_deref_var *b_var = void_b; + + if (a_var->var != b_var->var) + return false; + + for (const nir_deref *a = a_var->deref.child, *b = b_var->deref.child; + a != NULL; a = a->child, b = b->child) { + if (a->deref_type != b->deref_type) + return false; + + switch (a->deref_type) { + case nir_deref_type_array: { + nir_deref_array *a_arr = nir_deref_as_array(a); + nir_deref_array *b_arr = nir_deref_as_array(b); + + if (a_arr->deref_array_type != b_arr->deref_array_type) + return false; + + if (a_arr->deref_array_type == nir_deref_array_type_direct && + a_arr->base_offset != b_arr->base_offset) + return false; + break; + } + case nir_deref_type_struct: + if (nir_deref_as_struct(a)->index != nir_deref_as_struct(b)->index) + return false; + break; + default: + assert("Invalid deref chain"); + return false; + } + + assert((a->child == NULL) == (b->child == NULL)); + if((a->child == NULL) != (b->child == NULL)) + return false; + } + + return true; +} + +static int +type_get_length(const struct glsl_type *type) +{ + switch (glsl_get_base_type(type)) { + case GLSL_TYPE_STRUCT: + case GLSL_TYPE_ARRAY: + return glsl_get_length(type); + case GLSL_TYPE_FLOAT: + case GLSL_TYPE_INT: + case GLSL_TYPE_UINT: + case GLSL_TYPE_BOOL: + if (glsl_type_is_matrix(type)) + return glsl_get_matrix_columns(type); + else + return glsl_get_vector_elements(type); + default: + unreachable("Invalid deref base type"); + } +} + +static struct deref_node * +deref_node_create(struct deref_node *parent, + const struct glsl_type *type, void *mem_ctx) +{ + size_t size = sizeof(struct deref_node) + + type_get_length(type) * sizeof(struct deref_node *); + + struct deref_node *node = rzalloc_size(mem_ctx, size); + node->type = type; + node->parent = parent; + + return node; +} + +/* Gets the deref_node for the given deref chain and creates it if it + * doesn't yet exist. If the deref is fully-qualified and direct and + * add_to_direct_deref_nodes is true, it will be added to the hash table of + * of fully-qualified direct derefs. + */ +static struct deref_node * +get_deref_node(nir_deref_var *deref, bool add_to_direct_deref_nodes, + struct lower_variables_state *state) +{ + bool is_direct = true; + + struct deref_node *node; + + struct hash_entry *var_entry = + _mesa_hash_table_search(state->deref_var_nodes, deref->var); + + if (var_entry) { + node = var_entry->data; + } else { + node = deref_node_create(NULL, deref->deref.type, state->dead_ctx); + _mesa_hash_table_insert(state->deref_var_nodes, deref->var, node); + } + + for (nir_deref *tail = deref->deref.child; tail; tail = tail->child) { + switch (tail->deref_type) { + case nir_deref_type_struct: { + nir_deref_struct *deref_struct = nir_deref_as_struct(tail); + + assert(deref_struct->index < type_get_length(node->type)); + + if (node->children[deref_struct->index] == NULL) + node->children[deref_struct->index] = + deref_node_create(node, tail->type, state->dead_ctx); + + node = node->children[deref_struct->index]; + break; + } + + case nir_deref_type_array: { + nir_deref_array *arr = nir_deref_as_array(tail); + + switch (arr->deref_array_type) { + case nir_deref_array_type_direct: + /* This is possible if a loop unrolls and generates an + * out-of-bounds offset. We need to handle this at least + * somewhat gracefully. + */ + if (arr->base_offset >= type_get_length(node->type)) + return NULL; + + if (node->children[arr->base_offset] == NULL) + node->children[arr->base_offset] = + deref_node_create(node, tail->type, state->dead_ctx); + + node = node->children[arr->base_offset]; + break; + + case nir_deref_array_type_indirect: + if (node->indirect == NULL) + node->indirect = deref_node_create(node, tail->type, + state->dead_ctx); + + node = node->indirect; + is_direct = false; + break; + + case nir_deref_array_type_wildcard: + if (node->wildcard == NULL) + node->wildcard = deref_node_create(node, tail->type, + state->dead_ctx); + + node = node->wildcard; + is_direct = false; + break; + + default: + unreachable("Invalid array deref type"); + } + break; + } + default: + unreachable("Invalid deref type"); + } + } + + assert(node); + + if (is_direct && add_to_direct_deref_nodes) + _mesa_hash_table_insert(state->direct_deref_nodes, deref, node); + + return node; +} + +/* \sa foreach_deref_node_match */ +static bool +foreach_deref_node_worker(struct deref_node *node, nir_deref *deref, + bool (* cb)(struct deref_node *node, + struct lower_variables_state *state), + struct lower_variables_state *state) +{ + if (deref->child == NULL) { + return cb(node, state); + } else { + switch (deref->child->deref_type) { + case nir_deref_type_array: { + nir_deref_array *arr = nir_deref_as_array(deref->child); + assert(arr->deref_array_type == nir_deref_array_type_direct); + if (node->children[arr->base_offset] && + !foreach_deref_node_worker(node->children[arr->base_offset], + deref->child, cb, state)) + return false; + + if (node->wildcard && + !foreach_deref_node_worker(node->wildcard, + deref->child, cb, state)) + return false; + + return true; + } + + case nir_deref_type_struct: { + nir_deref_struct *str = nir_deref_as_struct(deref->child); + return foreach_deref_node_worker(node->children[str->index], + deref->child, cb, state); + } + + default: + unreachable("Invalid deref child type"); + } + } +} + +/* Walks over every "matching" deref_node and calls the callback. A node + * is considered to "match" if either refers to that deref or matches up t + * a wildcard. In other words, the following would match a[6].foo[3].bar: + * + * a[6].foo[3].bar + * a[*].foo[3].bar + * a[6].foo[*].bar + * a[*].foo[*].bar + * + * The given deref must be a full-length and fully qualified (no wildcards + * or indirects) deref chain. + */ +static bool +foreach_deref_node_match(nir_deref_var *deref, + bool (* cb)(struct deref_node *node, + struct lower_variables_state *state), + struct lower_variables_state *state) +{ + nir_deref_var var_deref = *deref; + var_deref.deref.child = NULL; + struct deref_node *node = get_deref_node(&var_deref, false, state); + + if (node == NULL) + return false; + + return foreach_deref_node_worker(node, &deref->deref, cb, state); +} + +/* \sa deref_may_be_aliased */ +static bool +deref_may_be_aliased_node(struct deref_node *node, nir_deref *deref, + struct lower_variables_state *state) +{ + if (deref->child == NULL) { + return false; + } else { + switch (deref->child->deref_type) { + case nir_deref_type_array: { + nir_deref_array *arr = nir_deref_as_array(deref->child); + if (arr->deref_array_type == nir_deref_array_type_indirect) + return true; + + assert(arr->deref_array_type == nir_deref_array_type_direct); + + if (node->children[arr->base_offset] && + deref_may_be_aliased_node(node->children[arr->base_offset], + deref->child, state)) + return true; + + if (node->wildcard && + deref_may_be_aliased_node(node->wildcard, deref->child, state)) + return true; + + return false; + } + + case nir_deref_type_struct: { + nir_deref_struct *str = nir_deref_as_struct(deref->child); + if (node->children[str->index]) { + return deref_may_be_aliased_node(node->children[str->index], + deref->child, state); + } else { + return false; + } + } + + default: + unreachable("Invalid nir_deref child type"); + } + } +} + +/* Returns true if there are no indirects that can ever touch this deref. + * + * For example, if the given deref is a[6].foo, then any uses of a[i].foo + * would cause this to return false, but a[i].bar would not affect it + * because it's a different structure member. A var_copy involving of + * a[*].bar also doesn't affect it because that can be lowered to entirely + * direct load/stores. + * + * We only support asking this question about fully-qualified derefs. + * Obviously, it's pointless to ask this about indirects, but we also + * rule-out wildcards. Handling Wildcard dereferences would involve + * checking each array index to make sure that there aren't any indirect + * references. + */ +static bool +deref_may_be_aliased(nir_deref_var *deref, + struct lower_variables_state *state) +{ + nir_deref_var var_deref = *deref; + var_deref.deref.child = NULL; + struct deref_node *node = get_deref_node(&var_deref, false, state); + + /* An invalid dereference can't be aliased. */ + if (node == NULL) + return false; + + return deref_may_be_aliased_node(node, &deref->deref, state); +} + +static void +register_load_instr(nir_intrinsic_instr *load_instr, bool create_node, + struct lower_variables_state *state) +{ + struct deref_node *node = get_deref_node(load_instr->variables[0], + create_node, state); + if (node == NULL) + return; + + if (node->loads == NULL) + node->loads = _mesa_set_create(state->dead_ctx, + _mesa_key_pointer_equal); + + _mesa_set_add(node->loads, _mesa_hash_pointer(load_instr), load_instr); +} + +static void +register_store_instr(nir_intrinsic_instr *store_instr, bool create_node, + struct lower_variables_state *state) +{ + struct deref_node *node = get_deref_node(store_instr->variables[0], + create_node, state); + if (node == NULL) + return; + + if (node->stores == NULL) + node->stores = _mesa_set_create(state->dead_ctx, + _mesa_key_pointer_equal); + + _mesa_set_add(node->stores, _mesa_hash_pointer(store_instr), store_instr); +} + +static void +register_copy_instr(nir_intrinsic_instr *copy_instr, bool create_node, + struct lower_variables_state *state) +{ + for (unsigned idx = 0; idx < 2; idx++) { + struct deref_node *node = get_deref_node(copy_instr->variables[idx], + create_node, state); + if (node == NULL) + continue; + + if (node->copies == NULL) + node->copies = _mesa_set_create(state->dead_ctx, + _mesa_key_pointer_equal); + + _mesa_set_add(node->copies, _mesa_hash_pointer(copy_instr), copy_instr); + } +} + +/* Registers all variable uses in the given block. */ +static bool +register_variable_uses_block(nir_block *block, void *void_state) +{ + struct lower_variables_state *state = void_state; + + nir_foreach_instr_safe(block, instr) { + if (instr->type != nir_instr_type_intrinsic) + continue; + + nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); + + switch (intrin->intrinsic) { + case nir_intrinsic_load_var: + register_load_instr(intrin, true, state); + break; + + case nir_intrinsic_store_var: + register_store_instr(intrin, true, state); + break; + + case nir_intrinsic_copy_var: + register_copy_instr(intrin, true, state); + break; + + default: + continue; + } + } + + return true; +} + +/* Walks down the deref chain and returns the next deref in the chain whose + * child is a wildcard. In other words, given the chain a[1].foo[*].bar, + * this function will return the deref to foo. Calling it a second time + * with the [*].bar, it will return NULL. + */ +static nir_deref * +deref_next_wildcard_parent(nir_deref *deref) +{ + for (nir_deref *tail = deref; tail->child; tail = tail->child) { + if (tail->child->deref_type != nir_deref_type_array) + continue; + + nir_deref_array *arr = nir_deref_as_array(tail->child); + + if (arr->deref_array_type == nir_deref_array_type_wildcard) + return tail; + } + + return NULL; +} + +/* Returns the last deref in the chain. + */ +static nir_deref * +get_deref_tail(nir_deref *deref) +{ + while (deref->child) + deref = deref->child; + + return deref; +} + +/* This function recursively walks the given deref chain and replaces the + * given copy instruction with an equivalent sequence load/store + * operations. + * + * @copy_instr The copy instruction to replace; new instructions will be + * inserted before this one + * + * @dest_head The head of the destination variable deref chain + * + * @src_head The head of the source variable deref chain + * + * @dest_tail The current tail of the destination variable deref chain; + * this is used for recursion and external callers of this + * function should call it with tail == head + * + * @src_tail The current tail of the source variable deref chain; + * this is used for recursion and external callers of this + * function should call it with tail == head + * + * @state The current variable lowering state + */ +static void +emit_copy_load_store(nir_intrinsic_instr *copy_instr, + nir_deref_var *dest_head, nir_deref_var *src_head, + nir_deref *dest_tail, nir_deref *src_tail, + struct lower_variables_state *state) +{ + /* Find the next pair of wildcards */ + nir_deref *src_arr_parent = deref_next_wildcard_parent(src_tail); + nir_deref *dest_arr_parent = deref_next_wildcard_parent(dest_tail); + + if (src_arr_parent || dest_arr_parent) { + /* Wildcards had better come in matched pairs */ + assert(dest_arr_parent && dest_arr_parent); + + nir_deref_array *src_arr = nir_deref_as_array(src_arr_parent->child); + nir_deref_array *dest_arr = nir_deref_as_array(dest_arr_parent->child); + + unsigned length = type_get_length(src_arr_parent->type); + /* The wildcards should represent the same number of elements */ + assert(length == type_get_length(dest_arr_parent->type)); + assert(length > 0); + + /* Walk over all of the elements that this wildcard refers to and + * call emit_copy_load_store on each one of them */ + src_arr->deref_array_type = nir_deref_array_type_direct; + dest_arr->deref_array_type = nir_deref_array_type_direct; + for (unsigned i = 0; i < length; i++) { + src_arr->base_offset = i; + dest_arr->base_offset = i; + emit_copy_load_store(copy_instr, dest_head, src_head, + &dest_arr->deref, &src_arr->deref, state); + } + src_arr->deref_array_type = nir_deref_array_type_wildcard; + dest_arr->deref_array_type = nir_deref_array_type_wildcard; + } else { + /* In this case, we have no wildcards anymore, so all we have to do + * is just emit the load and store operations. */ + src_tail = get_deref_tail(src_tail); + dest_tail = get_deref_tail(dest_tail); + + assert(src_tail->type == dest_tail->type); + + unsigned num_components = glsl_get_vector_elements(src_tail->type); + + nir_deref *src_deref = nir_copy_deref(state->mem_ctx, &src_head->deref); + nir_deref *dest_deref = nir_copy_deref(state->mem_ctx, &dest_head->deref); + + nir_intrinsic_instr *load = + nir_intrinsic_instr_create(state->mem_ctx, nir_intrinsic_load_var); + load->num_components = num_components; + load->variables[0] = nir_deref_as_var(src_deref); + load->dest.is_ssa = true; + nir_ssa_def_init(&load->instr, &load->dest.ssa, num_components, NULL); + + nir_instr_insert_before(©_instr->instr, &load->instr); + register_load_instr(load, false, state); + + nir_intrinsic_instr *store = + nir_intrinsic_instr_create(state->mem_ctx, nir_intrinsic_store_var); + store->num_components = num_components; + store->variables[0] = nir_deref_as_var(dest_deref); + store->src[0].is_ssa = true; + store->src[0].ssa = &load->dest.ssa; + + nir_instr_insert_before(©_instr->instr, &store->instr); + register_store_instr(store, false, state); + } +} + +/* Walks over all of the copy instructions to or from the given deref_node + * and lowers them to load/store intrinsics. + */ +static bool +lower_copies_to_load_store(struct deref_node *node, + struct lower_variables_state *state) +{ + if (!node->copies) + return true; + + struct set_entry *copy_entry; + set_foreach(node->copies, copy_entry) { + nir_intrinsic_instr *copy = (void *)copy_entry->key; + + emit_copy_load_store(copy, copy->variables[0], copy->variables[1], + ©->variables[0]->deref, + ©->variables[1]->deref, + state); + + for (unsigned i = 0; i < 2; ++i) { + struct deref_node *arg_node = get_deref_node(copy->variables[i], + false, state); + if (arg_node == NULL) + continue; + + struct set_entry *arg_entry = _mesa_set_search(arg_node->copies, + copy_entry->hash, + copy); + assert(arg_entry); + _mesa_set_remove(node->copies, arg_entry); + } + + nir_instr_remove(©->instr); + } + + return true; +} + +/* Returns a load_const instruction that represents the constant + * initializer for the given deref chain. The caller is responsible for + * ensuring that there actually is a constant initializer. + */ +static nir_load_const_instr * +get_const_initializer_load(const nir_deref_var *deref, + struct lower_variables_state *state) +{ + nir_constant *constant = deref->var->constant_initializer; + const nir_deref *tail = &deref->deref; + unsigned matrix_offset = 0; + while (tail->child) { + switch (tail->child->deref_type) { + case nir_deref_type_array: { + nir_deref_array *arr = nir_deref_as_array(tail->child); + assert(arr->deref_array_type == nir_deref_array_type_direct); + if (glsl_type_is_matrix(tail->type)) { + assert(arr->deref.child == NULL); + matrix_offset = arr->base_offset; + } else { + constant = constant->elements[arr->base_offset]; + } + break; + } + + case nir_deref_type_struct: { + constant = constant->elements[nir_deref_as_struct(tail->child)->index]; + break; + } + + default: + unreachable("Invalid deref child type"); + } + + tail = tail->child; + } + + nir_load_const_instr *load = + nir_load_const_instr_create(state->mem_ctx, + glsl_get_vector_elements(tail->type)); + + matrix_offset *= load->def.num_components; + for (unsigned i = 0; i < load->def.num_components; i++) { + switch (glsl_get_base_type(tail->type)) { + case GLSL_TYPE_FLOAT: + case GLSL_TYPE_INT: + case GLSL_TYPE_UINT: + load->value.u[i] = constant->value.u[matrix_offset + i]; + break; + case GLSL_TYPE_BOOL: + load->value.u[i] = constant->value.u[matrix_offset + i] ? + NIR_TRUE : NIR_FALSE; + break; + default: + unreachable("Invalid immediate type"); + } + } + + return load; +} + +/** Pushes an SSA def onto the def stack for the given node + * + * Each node is potentially associated with a stack of SSA definitions. + * This stack is used for determining what SSA definition reaches a given + * point in the program for variable renaming. The stack is always kept in + * dominance-order with at most one SSA def per block. If the SSA + * definition on the top of the stack is in the same block as the one being + * pushed, the top element is replaced. + */ +static void +def_stack_push(struct deref_node *node, nir_ssa_def *def, + struct lower_variables_state *state) +{ + if (node->def_stack == NULL) { + node->def_stack = ralloc_array(state->dead_ctx, nir_ssa_def *, + state->impl->num_blocks); + node->def_stack_tail = node->def_stack - 1; + } + + if (node->def_stack_tail >= node->def_stack) { + nir_ssa_def *top_def = *node->def_stack_tail; + + if (def->parent_instr->block == top_def->parent_instr->block) { + /* They're in the same block, just replace the top */ + *node->def_stack_tail = def; + return; + } + } + + *(++node->def_stack_tail) = def; +} + +/* Pop the top of the def stack if it's in the given block */ +static void +def_stack_pop_if_in_block(struct deref_node *node, nir_block *block) +{ + /* If we're popping, then we have presumably pushed at some time in the + * past so this should exist. + */ + assert(node->def_stack != NULL); + + /* The stack is already empty. Do nothing. */ + if (node->def_stack_tail < node->def_stack) + return; + + nir_ssa_def *def = *node->def_stack_tail; + if (def->parent_instr->block == block) + node->def_stack_tail--; +} + +/** Retrieves the SSA definition on the top of the stack for the given + * node, if one exists. If the stack is empty, then we return the constant + * initializer (if it exists) or an SSA undef. + */ +static nir_ssa_def * +get_ssa_def_for_block(struct deref_node *node, nir_block *block, + struct lower_variables_state *state) +{ + /* If we have something on the stack, go ahead and return it. We're + * assuming that the top of the stack dominates the given block. + */ + if (node->def_stack && node->def_stack_tail >= node->def_stack) + return *node->def_stack_tail; + + /* If we got here then we don't have a definition that dominates the + * given block. This means that we need to add an undef and use that. + */ + nir_ssa_undef_instr *undef = + nir_ssa_undef_instr_create(state->mem_ctx, + glsl_get_vector_elements(node->type)); + nir_instr_insert_before_cf_list(&state->impl->body, &undef->instr); + def_stack_push(node, &undef->def, state); + return &undef->def; +} + +/* Given a block and one of its predecessors, this function fills in the + * souces of the phi nodes to take SSA defs from the given predecessor. + * This function must be called exactly once per block/predecessor pair. + */ +static void +add_phi_sources(nir_block *block, nir_block *pred, + struct lower_variables_state *state) +{ + nir_foreach_instr(block, instr) { + if (instr->type != nir_instr_type_phi) + break; + + nir_phi_instr *phi = nir_instr_as_phi(instr); + + struct hash_entry *entry = + _mesa_hash_table_search(state->phi_table, phi); + if (!entry) + continue; + + struct deref_node *node = entry->data; + + nir_phi_src *src = ralloc(state->mem_ctx, nir_phi_src); + src->pred = pred; + src->src.is_ssa = true; + src->src.ssa = get_ssa_def_for_block(node, pred, state); + + _mesa_set_add(src->src.ssa->uses, _mesa_hash_pointer(instr), instr); + + exec_list_push_tail(&phi->srcs, &src->node); + } +} + +/* Performs variable renaming by doing a DFS of the dominance tree + * + * This algorithm is very similar to the one outlined in "Efficiently + * Computing Static Single Assignment Form and the Control Dependence + * Graph" by Cytron et. al. The primary difference is that we only put one + * SSA def on the stack per block. + */ +static bool +rename_variables_block(nir_block *block, struct lower_variables_state *state) +{ + nir_foreach_instr_safe(block, instr) { + if (instr->type == nir_instr_type_phi) { + nir_phi_instr *phi = nir_instr_as_phi(instr); + + struct hash_entry *entry = + _mesa_hash_table_search(state->phi_table, phi); + + /* This can happen if we already have phi nodes in the program + * that were not created in this pass. + */ + if (!entry) + continue; + + struct deref_node *node = entry->data; + + def_stack_push(node, &phi->dest.ssa, state); + } else if (instr->type == nir_instr_type_intrinsic) { + nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); + + switch (intrin->intrinsic) { + case nir_intrinsic_load_var: { + struct deref_node *node = get_deref_node(intrin->variables[0], + false, state); + + if (node == NULL) { + /* If we hit this path then we are referencing an invalid + * value. Most likely, we unrolled something and are + * reading past the end of some array. In any case, this + * should result in an undefined value. + */ + nir_ssa_undef_instr *undef = + nir_ssa_undef_instr_create(state->mem_ctx, + intrin->num_components); + + nir_instr_insert_before(&intrin->instr, &undef->instr); + nir_instr_remove(&intrin->instr); + + nir_src new_src = { + .is_ssa = true, + .ssa = &undef->def, + }; + + nir_ssa_def_rewrite_uses(&intrin->dest.ssa, new_src, + state->mem_ctx); + continue; + } + + if (!node->lower_to_ssa) + continue; + + nir_alu_instr *mov = nir_alu_instr_create(state->mem_ctx, + nir_op_imov); + mov->src[0].src.is_ssa = true; + mov->src[0].src.ssa = get_ssa_def_for_block(node, block, state); + for (unsigned i = intrin->num_components; i < 4; i++) + mov->src[0].swizzle[i] = 0; + + assert(intrin->dest.is_ssa); + + mov->dest.write_mask = (1 << intrin->num_components) - 1; + mov->dest.dest.is_ssa = true; + nir_ssa_def_init(&mov->instr, &mov->dest.dest.ssa, + intrin->num_components, NULL); + + nir_instr_insert_before(&intrin->instr, &mov->instr); + nir_instr_remove(&intrin->instr); + + nir_src new_src = { + .is_ssa = true, + .ssa = &mov->dest.dest.ssa, + }; + + nir_ssa_def_rewrite_uses(&intrin->dest.ssa, new_src, + state->mem_ctx); + break; + } + + case nir_intrinsic_store_var: { + struct deref_node *node = get_deref_node(intrin->variables[0], + false, state); + + if (node == NULL) { + /* Probably an out-of-bounds array store. That should be a + * no-op. */ + nir_instr_remove(&intrin->instr); + continue; + } + + if (!node->lower_to_ssa) + continue; + + assert(intrin->num_components == + glsl_get_vector_elements(node->type)); + + assert(intrin->src[0].is_ssa); + + nir_alu_instr *mov = nir_alu_instr_create(state->mem_ctx, + nir_op_imov); + mov->src[0].src.is_ssa = true; + mov->src[0].src.ssa = intrin->src[0].ssa; + for (unsigned i = intrin->num_components; i < 4; i++) + mov->src[0].swizzle[i] = 0; + + mov->dest.write_mask = (1 << intrin->num_components) - 1; + mov->dest.dest.is_ssa = true; + nir_ssa_def_init(&mov->instr, &mov->dest.dest.ssa, + intrin->num_components, NULL); + + nir_instr_insert_before(&intrin->instr, &mov->instr); + + def_stack_push(node, &mov->dest.dest.ssa, state); + + /* We'll wait to remove the instruction until the next pass + * where we pop the node we just pushed back off the stack. + */ + break; + } + + default: + break; + } + } + } + + if (block->successors[0]) + add_phi_sources(block->successors[0], block, state); + if (block->successors[1]) + add_phi_sources(block->successors[1], block, state); + + for (unsigned i = 0; i < block->num_dom_children; ++i) + rename_variables_block(block->dom_children[i], state); + + /* Now we iterate over the instructions and pop off any SSA defs that we + * pushed in the first loop. + */ + nir_foreach_instr_safe(block, instr) { + if (instr->type == nir_instr_type_phi) { + nir_phi_instr *phi = nir_instr_as_phi(instr); + + struct hash_entry *entry = + _mesa_hash_table_search(state->phi_table, phi); + + /* This can happen if we already have phi nodes in the program + * that were not created in this pass. + */ + if (!entry) + continue; + + struct deref_node *node = entry->data; + + def_stack_pop_if_in_block(node, block); + } else if (instr->type == nir_instr_type_intrinsic) { + nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); + + if (intrin->intrinsic != nir_intrinsic_store_var) + continue; + + struct deref_node *node = get_deref_node(intrin->variables[0], + false, state); + if (!node) + continue; + + if (!node->lower_to_ssa) + continue; + + def_stack_pop_if_in_block(node, block); + nir_instr_remove(&intrin->instr); + } + } + + return true; +} + +/* Inserts phi nodes for all variables marked lower_to_ssa + * + * This is the same algorithm as presented in "Efficiently Computing Static + * Single Assignment Form and the Control Dependence Graph" by Cytron et. + * al. + */ +static void +insert_phi_nodes(struct lower_variables_state *state) +{ + unsigned work[state->impl->num_blocks]; + unsigned has_already[state->impl->num_blocks]; + + /* + * Since the work flags already prevent us from inserting a node that has + * ever been inserted into W, we don't need to use a set to represent W. + * Also, since no block can ever be inserted into W more than once, we know + * that the maximum size of W is the number of basic blocks in the + * function. So all we need to handle W is an array and a pointer to the + * next element to be inserted and the next element to be removed. + */ + nir_block *W[state->impl->num_blocks]; + + memset(work, 0, sizeof work); + memset(has_already, 0, sizeof has_already); + + unsigned w_start, w_end; + unsigned iter_count = 0; + + struct hash_entry *deref_entry; + hash_table_foreach(state->direct_deref_nodes, deref_entry) { + struct deref_node *node = deref_entry->data; + + if (node->stores == NULL) + continue; + + if (!node->lower_to_ssa) + continue; + + w_start = w_end = 0; + iter_count++; + + struct set_entry *store_entry; + set_foreach(node->stores, store_entry) { + nir_intrinsic_instr *store = (nir_intrinsic_instr *)store_entry->key; + if (work[store->instr.block->index] < iter_count) + W[w_end++] = store->instr.block; + work[store->instr.block->index] = iter_count; + } + + while (w_start != w_end) { + nir_block *cur = W[w_start++]; + struct set_entry *dom_entry; + set_foreach(cur->dom_frontier, dom_entry) { + nir_block *next = (nir_block *) dom_entry->key; + + /* + * If there's more than one return statement, then the end block + * can be a join point for some definitions. However, there are + * no instructions in the end block, so nothing would use those + * phi nodes. Of course, we couldn't place those phi nodes + * anyways due to the restriction of having no instructions in the + * end block... + */ + if (next == state->impl->end_block) + continue; + + if (has_already[next->index] < iter_count) { + nir_phi_instr *phi = nir_phi_instr_create(state->mem_ctx); + phi->dest.is_ssa = true; + nir_ssa_def_init(&phi->instr, &phi->dest.ssa, + glsl_get_vector_elements(node->type), NULL); + nir_instr_insert_before_block(next, &phi->instr); + + _mesa_hash_table_insert(state->phi_table, phi, node); + + has_already[next->index] = iter_count; + if (work[next->index] < iter_count) { + work[next->index] = iter_count; + W[w_end++] = next; + } + } + } + } + } +} + + +/** Implements a pass to lower variable uses to SSA values + * + * This path walks the list of instructions and tries to lower as many + * local variable load/store operations to SSA defs and uses as it can. + * The process involves four passes: + * + * 1) Iterate over all of the instructions and mark where each local + * variable deref is used in a load, store, or copy. While we're at + * it, we keep track of all of the fully-qualified (no wildcards) and + * fully-direct references we see and store them in the + * direct_deref_nodes hash table. + * + * 2) Walk over the the list of fully-qualified direct derefs generated in + * the previous pass. For each deref, we determine if it can ever be + * aliased, i.e. if there is an indirect reference anywhere that may + * refer to it. If it cannot be aliased, we mark it for lowering to an + * SSA value. At this point, we lower any var_copy instructions that + * use the given deref to load/store operations and, if the deref has a + * constant initializer, we go ahead and add a load_const value at the + * beginning of the function with the initialized value. + * + * 3) Walk over the list of derefs we plan to lower to SSA values and + * insert phi nodes as needed. + * + * 4) Perform "variable renaming" by replacing the load/store instructions + * with SSA definitions and SSA uses. + */ +static bool +nir_lower_vars_to_ssa_impl(nir_function_impl *impl) +{ + struct lower_variables_state state; + + state.mem_ctx = ralloc_parent(impl); + state.dead_ctx = ralloc_context(state.mem_ctx); + state.impl = impl; + + state.deref_var_nodes = _mesa_hash_table_create(state.dead_ctx, + _mesa_hash_pointer, + _mesa_key_pointer_equal); + state.direct_deref_nodes = _mesa_hash_table_create(state.dead_ctx, + hash_deref, derefs_equal); + state.phi_table = _mesa_hash_table_create(state.dead_ctx, + _mesa_hash_pointer, + _mesa_key_pointer_equal); + + nir_foreach_block(impl, register_variable_uses_block, &state); + + struct set *outputs = _mesa_set_create(state.dead_ctx, + _mesa_key_pointer_equal); + + bool progress = false; + + nir_metadata_require(impl, nir_metadata_block_index); + + struct hash_entry *entry; + hash_table_foreach(state.direct_deref_nodes, entry) { + nir_deref_var *deref = (void *)entry->key; + struct deref_node *node = entry->data; + + if (deref->var->data.mode != nir_var_local) { + _mesa_hash_table_remove(state.direct_deref_nodes, entry); + continue; + } + + if (deref_may_be_aliased(deref, &state)) { + _mesa_hash_table_remove(state.direct_deref_nodes, entry); + continue; + } + + node->lower_to_ssa = true; + progress = true; + + if (deref->var->constant_initializer) { + nir_load_const_instr *load = get_const_initializer_load(deref, &state); + nir_ssa_def_init(&load->instr, &load->def, + glsl_get_vector_elements(node->type), NULL); + nir_instr_insert_before_cf_list(&impl->body, &load->instr); + def_stack_push(node, &load->def, &state); + } + + if (deref->var->data.mode == nir_var_shader_out) + _mesa_set_add(outputs, _mesa_hash_pointer(node), node); + + foreach_deref_node_match(deref, lower_copies_to_load_store, &state); + } + + if (!progress) + return false; + + nir_metadata_require(impl, nir_metadata_dominance); + + insert_phi_nodes(&state); + rename_variables_block(impl->start_block, &state); + + nir_metadata_preserve(impl, nir_metadata_block_index | + nir_metadata_dominance); + + ralloc_free(state.dead_ctx); + + return progress; +} + +void +nir_lower_vars_to_ssa(nir_shader *shader) +{ + nir_foreach_overload(shader, overload) { + if (overload->impl) + nir_lower_vars_to_ssa_impl(overload->impl); + } +} diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp index 4c91a6edc44..218cd5ce172 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp @@ -43,7 +43,7 @@ fs_visitor::emit_nir_code() bool progress; do { progress = false; - nir_lower_variables(nir); + nir_lower_vars_to_ssa(nir); nir_validate_shader(nir); progress |= nir_copy_prop(nir); nir_validate_shader(nir);