diff options
Diffstat (limited to 'src/compiler/nir')
| -rw-r--r-- | src/compiler/nir/meson.build | 1 | ||||
| -rw-r--r-- | src/compiler/nir/nir.h | 1 | ||||
| -rw-r--r-- | src/compiler/nir/nir_move_load_const.c | 141 |
3 files changed, 143 insertions, 0 deletions
diff --git a/src/compiler/nir/meson.build b/src/compiler/nir/meson.build index 598c68aff9f..2b5da68c78b 100644 --- a/src/compiler/nir/meson.build +++ b/src/compiler/nir/meson.build @@ -145,6 +145,7 @@ files_libnir = files( 'nir_lower_wpos_ytransform.c', 'nir_lower_bit_size.c', 'nir_metadata.c', + 'nir_move_load_const.c', 'nir_move_vec_src_uses_to_dest.c', 'nir_normalize_cubemap_coords.c', 'nir_opt_conditional_discard.c', diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h index 2858e1f2880..66764eeaf29 100644 --- a/src/compiler/nir/nir.h +++ b/src/compiler/nir/nir.h @@ -2632,6 +2632,7 @@ bool nir_remove_dead_variables(nir_shader *shader, nir_variable_mode modes); bool nir_lower_constant_initializers(nir_shader *shader, nir_variable_mode modes); +bool nir_move_load_const(nir_shader *shader); bool nir_move_vec_src_uses_to_dest(nir_shader *shader); bool nir_lower_vec_to_movs(nir_shader *shader); void nir_lower_alpha_test(nir_shader *shader, enum compare_func func, diff --git a/src/compiler/nir/nir_move_load_const.c b/src/compiler/nir/nir_move_load_const.c new file mode 100644 index 00000000000..abc53fdce6a --- /dev/null +++ b/src/compiler/nir/nir_move_load_const.c @@ -0,0 +1,141 @@ +/* + * Copyright © 2018 Red Hat + * + * 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: + * Rob Clark ([email protected]> + * + */ + +#include "nir.h" + + +/* + * A simple pass that moves load_const's into consuming block if + * they are only consumed in a single block, to try to counter- + * act nir's tendency to move all load_const to the top of the + * first block. + */ + +/* iterate a ssa def's use's and try to find a more optimal block to + * move it to, using the dominance tree. In short, if all of the uses + * are contained in a single block, the load will be moved there, + * otherwise it will be move to the least common ancestor block of all + * the uses + */ +static nir_block * +get_preferred_block(nir_ssa_def *def) +{ + nir_block *lca = NULL; + + /* hmm, probably ignore if-uses: */ + if (!list_empty(&def->if_uses)) + return NULL; + + nir_foreach_use(use, def) { + nir_instr *instr = use->parent_instr; + nir_block *use_block = instr->block; + + /* + * Kind of an ugly special-case, but phi instructions + * need to appear first in the block, so by definition + * we can't move a load_immed into a block where it is + * consumed by a phi instruction. We could conceivably + * move it into a dominator block. + */ + if (instr->type == nir_instr_type_phi) { + nir_phi_instr *phi = nir_instr_as_phi(instr); + nir_block *phi_lca = NULL; + nir_foreach_phi_src(src, phi) + phi_lca = nir_dominance_lca(phi_lca, src->pred); + use_block = phi_lca; + } + + lca = nir_dominance_lca(lca, use_block); + } + + return lca; +} + +/* insert before first non-phi instruction: */ +static void +insert_after_phi(nir_instr *instr, nir_block *block) +{ + nir_foreach_instr(instr2, block) { + if (instr2->type == nir_instr_type_phi) + continue; + + exec_node_insert_node_before(&instr2->node, + &instr->node); + + return; + } + + /* if haven't inserted it, push to tail (ie. empty block or possibly + * a block only containing phi's?) + */ + exec_list_push_tail(&block->instr_list, &instr->node); +} + +bool +nir_move_load_const(nir_shader *shader) +{ + bool progress = false; + + nir_foreach_function(function, shader) { + if (!function->impl) + continue; + + nir_foreach_block(block, function->impl) { + nir_metadata_require(function->impl, + nir_metadata_block_index | nir_metadata_dominance); + + nir_foreach_instr_safe(instr, block) { + if (instr->type != nir_instr_type_load_const) + continue; + + nir_load_const_instr *load = + nir_instr_as_load_const(instr); + nir_block *use_block = + get_preferred_block(&load->def); + + if (!use_block) + continue; + + if (use_block == load->instr.block) + continue; + + exec_node_remove(&load->instr.node); + + insert_after_phi(&load->instr, use_block); + + load->instr.block = use_block; + + progress = true; + } + } + + nir_metadata_preserve(function->impl, + nir_metadata_block_index | nir_metadata_dominance); + } + + return progress; +} |