From: Jason Ekstrand Date: Tue, 21 Apr 2015 18:16:04 +0000 (-0700) Subject: nir: Modernize the out-of-SSA pass X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=6702ebce5760aae0eb15f410c2a83b6e893b005c;p=mesa.git nir: Modernize the out-of-SSA pass The out-of-SSA pass was one of the first passes written when getting SSA up-and-going (for obvious reasons). As such, it came before a lot of the nifty SSA-based helpers were introduced. This commit modernizes it so that we're no longer doing nearly as much manual banging on use/def sets. Reviewed-by: Connor Abbott --- diff --git a/src/glsl/nir/nir_from_ssa.c b/src/glsl/nir/nir_from_ssa.c index 6a3b141bd3f..512fdacc53a 100644 --- a/src/glsl/nir/nir_from_ssa.c +++ b/src/glsl/nir/nir_from_ssa.c @@ -37,7 +37,6 @@ struct from_ssa_state { void *mem_ctx; void *dead_ctx; - struct hash_table *ssa_table; struct hash_table *merge_node_table; nir_instr *instr; nir_function_impl *impl; @@ -344,45 +343,31 @@ isolate_phi_nodes_block(nir_block *block, void *void_state) get_parallel_copy_at_end_of_block(src->pred); assert(pcopy); - nir_parallel_copy_entry *entry = ralloc(state->dead_ctx, - nir_parallel_copy_entry); - exec_list_push_tail(&pcopy->entries, &entry->node); - - nir_src_copy(&entry->src, &src->src, state->dead_ctx); - _mesa_set_add(src->src.ssa->uses, &pcopy->instr); - + nir_parallel_copy_entry *entry = rzalloc(state->dead_ctx, + nir_parallel_copy_entry); nir_ssa_dest_init(&pcopy->instr, &entry->dest, phi->dest.ssa.num_components, src->src.ssa->name); + exec_list_push_tail(&pcopy->entries, &entry->node); - struct set_entry *use_entry = - _mesa_set_search(src->src.ssa->uses, instr); - if (use_entry) - /* It is possible that a phi node can use the same source twice - * but for different basic blocks. If that happens, entry will - * be NULL because we already deleted it. This is safe - * because, by the time the loop is done, we will have deleted - * all of the sources of the phi from their respective use sets - * and moved them to the parallel copy definitions. - */ - _mesa_set_remove(src->src.ssa->uses, use_entry); + assert(src->src.is_ssa); + nir_instr_rewrite_src(&pcopy->instr, &entry->src, src->src); - src->src.ssa = &entry->dest.ssa; - _mesa_set_add(entry->dest.ssa.uses, instr); + nir_instr_rewrite_src(&phi->instr, &src->src, + nir_src_for_ssa(&entry->dest.ssa)); } - nir_parallel_copy_entry *entry = ralloc(state->dead_ctx, - nir_parallel_copy_entry); - exec_list_push_tail(&block_pcopy->entries, &entry->node); - + nir_parallel_copy_entry *entry = rzalloc(state->dead_ctx, + nir_parallel_copy_entry); nir_ssa_dest_init(&block_pcopy->instr, &entry->dest, phi->dest.ssa.num_components, phi->dest.ssa.name); + exec_list_push_tail(&block_pcopy->entries, &entry->node); + nir_ssa_def_rewrite_uses(&phi->dest.ssa, nir_src_for_ssa(&entry->dest.ssa), state->mem_ctx); - entry->src.is_ssa = true; - entry->src.ssa = &phi->dest.ssa; - _mesa_set_add(phi->dest.ssa.uses, &block_pcopy->instr); + nir_instr_rewrite_src(&block_pcopy->instr, &entry->src, + nir_src_for_ssa(&phi->dest.ssa)); } return true; @@ -472,12 +457,16 @@ agressive_coalesce_block(nir_block *block, void *void_state) return true; } -static nir_register * -get_register_for_ssa_def(nir_ssa_def *def, struct from_ssa_state *state) +static bool +rewrite_ssa_def(nir_ssa_def *def, void *void_state) { + struct from_ssa_state *state = void_state; + nir_register *reg; + struct hash_entry *entry = _mesa_hash_table_search(state->merge_node_table, def); if (entry) { + /* In this case, we're part of a phi web. Use the web's register. */ merge_node *node = (merge_node *)entry->data; /* If it doesn't have a register yet, create one. Note that all of @@ -491,20 +480,15 @@ get_register_for_ssa_def(nir_ssa_def *def, struct from_ssa_state *state) node->set->reg->num_array_elems = 0; } - return node->set->reg; - } - - entry = _mesa_hash_table_search(state->ssa_table, def); - if (entry) { - return (nir_register *)entry->data; + reg = node->set->reg; } else { /* We leave load_const SSA values alone. They act as immediates to * the backend. If it got coalesced into a phi, that's ok. */ if (def->parent_instr->type == nir_instr_type_load_const) - return NULL; + return true; - nir_register *reg = nir_local_reg_create(state->impl); + reg = nir_local_reg_create(state->impl); reg->name = def->name; reg->num_components = def->num_components; reg->num_array_elems = 0; @@ -516,57 +500,27 @@ get_register_for_ssa_def(nir_ssa_def *def, struct from_ssa_state *state) */ if (def->parent_instr->type != nir_instr_type_ssa_undef) reg->parent_instr = def->parent_instr; - - _mesa_hash_table_insert(state->ssa_table, def, reg); - return reg; } -} -static bool -rewrite_ssa_src(nir_src *src, void *void_state) -{ - struct from_ssa_state *state = void_state; + nir_ssa_def_rewrite_uses(def, nir_src_for_reg(reg), state->mem_ctx); + assert(def->uses->entries == 0 && def->if_uses->entries == 0); - if (src->is_ssa) { - nir_register *reg = get_register_for_ssa_def(src->ssa, state); - - if (reg == NULL) { - assert(src->ssa->parent_instr->type == nir_instr_type_load_const); - return true; - } - - memset(src, 0, sizeof *src); - src->reg.reg = reg; - - /* We don't need to remove it from the uses set because that is going - * away. We just need to add it to the one for the register. */ - _mesa_set_add(reg->uses, state->instr); - } - - return true; -} - -static bool -rewrite_ssa_dest(nir_dest *dest, void *void_state) -{ - struct from_ssa_state *state = void_state; + if (def->parent_instr->type == nir_instr_type_ssa_undef) + return true; - if (dest->is_ssa) { - nir_register *reg = get_register_for_ssa_def(&dest->ssa, state); + assert(def->parent_instr->type != nir_instr_type_load_const); - if (reg == NULL) { - assert(dest->ssa.parent_instr->type == nir_instr_type_load_const); - return true; - } + /* At this point we know a priori that this SSA def is part of a + * nir_dest. We can use exec_node_data to get the dest pointer. + */ + nir_dest *dest = exec_node_data(nir_dest, def, ssa); - _mesa_set_destroy(dest->ssa.uses, NULL); - _mesa_set_destroy(dest->ssa.if_uses, NULL); + _mesa_set_destroy(dest->ssa.uses, NULL); + _mesa_set_destroy(dest->ssa.if_uses, NULL); - memset(dest, 0, sizeof *dest); - dest->reg.reg = reg; + *dest = nir_dest_for_reg(reg); - _mesa_set_add(reg->defs, state->instr); - } + _mesa_set_add(reg->defs, state->instr); return true; } @@ -581,8 +535,7 @@ resolve_registers_block(nir_block *block, void *void_state) nir_foreach_instr_safe(block, instr) { state->instr = instr; - nir_foreach_src(instr, rewrite_ssa_src, state); - nir_foreach_dest(instr, rewrite_ssa_dest, state); + nir_foreach_ssa_def(instr, rewrite_ssa_def, state); if (instr->type == nir_instr_type_ssa_undef || instr->type == nir_instr_type_phi) { @@ -592,23 +545,6 @@ resolve_registers_block(nir_block *block, void *void_state) } state->instr = NULL; - nir_if *following_if = nir_block_get_following_if(block); - if (following_if && following_if->condition.is_ssa) { - nir_register *reg = get_register_for_ssa_def(following_if->condition.ssa, - state); - if (reg) { - memset(&following_if->condition, 0, sizeof following_if->condition); - following_if->condition.reg.reg = reg; - - _mesa_set_add(reg->if_uses, following_if); - } else { - /* FIXME: We really shouldn't hit this. We should be doing - * constant control flow propagation. - */ - assert(following_if->condition.ssa->parent_instr->type == nir_instr_type_load_const); - } - } - return true; } @@ -855,8 +791,6 @@ nir_convert_from_ssa_impl(nir_function_impl *impl) nir_foreach_block(impl, coalesce_phi_nodes_block, &state); nir_foreach_block(impl, agressive_coalesce_block, &state); - state.ssa_table = _mesa_hash_table_create(NULL, _mesa_hash_pointer, - _mesa_key_pointer_equal); nir_foreach_block(impl, resolve_registers_block, &state); nir_foreach_block(impl, resolve_parallel_copies_block, &state); @@ -865,7 +799,6 @@ nir_convert_from_ssa_impl(nir_function_impl *impl) nir_metadata_dominance); /* Clean up dead instructions and the hash tables */ - _mesa_hash_table_destroy(state.ssa_table, NULL); _mesa_hash_table_destroy(state.merge_node_table, NULL); ralloc_free(state.dead_ctx); }