1/*
2 * Copyright © 2014 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 * Authors:
24 *    Jason Ekstrand (jason@jlekstrand.net)
25 *    Connor Abbott (cwabbott0@gmail.com)
26 *
27 */
28
29#include "nir_instr_set.h"
30
31/*
32 * Implements common subexpression elimination
33 */
34
35static bool
36dominates(const nir_instr *old_instr, const nir_instr *new_instr)
37{
38   return nir_block_dominates(old_instr->block, new_instr->block);
39}
40
41static bool
42nir_opt_cse_impl(nir_function_impl *impl)
43{
44   struct set *instr_set = nir_instr_set_create(NULL);
45
46   _mesa_set_resize(instr_set, impl->ssa_alloc);
47
48   nir_metadata_require(impl, nir_metadata_dominance);
49
50   bool progress = false;
51   nir_foreach_block(block, impl) {
52      nir_foreach_instr_safe(instr, block)
53         progress |= nir_instr_set_add_or_rewrite(instr_set, instr, dominates);
54   }
55
56   if (progress) {
57      nir_metadata_preserve(impl, nir_metadata_block_index |
58                                  nir_metadata_dominance);
59   } else {
60      nir_metadata_preserve(impl, nir_metadata_all);
61   }
62
63   nir_instr_set_destroy(instr_set);
64   return progress;
65}
66
67bool
68nir_opt_cse(nir_shader *shader)
69{
70   bool progress = false;
71
72   nir_foreach_function(function, shader) {
73      if (function->impl)
74         progress |= nir_opt_cse_impl(function->impl);
75   }
76
77   return progress;
78}
79
80