| /* |
| * 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) |
| * Connor Abbott (cwabbott0@gmail.com) |
| * |
| */ |
| |
| #include "nir_instr_set.h" |
| |
| /* |
| * Implements common subexpression elimination |
| */ |
| |
| /* |
| * Visits and CSE's the given block and all its descendants in the dominance |
| * tree recursively. Note that the instr_set is guaranteed to only ever |
| * contain instructions that dominate the current block. |
| */ |
| |
| static bool |
| cse_block(nir_block *block, struct set *instr_set) |
| { |
| bool progress = false; |
| |
| nir_foreach_instr_safe(block, instr) { |
| if (nir_instr_set_add_or_rewrite(instr_set, instr)) { |
| progress = true; |
| nir_instr_remove(instr); |
| } |
| } |
| |
| for (unsigned i = 0; i < block->num_dom_children; i++) { |
| nir_block *child = block->dom_children[i]; |
| progress |= cse_block(child, instr_set); |
| } |
| |
| nir_foreach_instr(block, instr) |
| nir_instr_set_remove(instr_set, instr); |
| |
| return progress; |
| } |
| |
| static bool |
| nir_opt_cse_impl(nir_function_impl *impl) |
| { |
| struct set *instr_set = nir_instr_set_create(NULL); |
| |
| nir_metadata_require(impl, nir_metadata_dominance); |
| |
| bool progress = cse_block(nir_start_block(impl), instr_set); |
| |
| if (progress) |
| nir_metadata_preserve(impl, nir_metadata_block_index | |
| nir_metadata_dominance); |
| |
| nir_instr_set_destroy(instr_set); |
| return progress; |
| } |
| |
| bool |
| nir_opt_cse(nir_shader *shader) |
| { |
| bool progress = false; |
| |
| nir_foreach_function(shader, function) { |
| if (function->impl) |
| progress |= nir_opt_cse_impl(function->impl); |
| } |
| |
| return progress; |
| } |
| |