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 * Connor Abbott (cwabbott0@gmail.com)
25 *
26 */
27
28 #include "nir.h"
29
30 static bool
global_to_local(nir_register * reg)31 global_to_local(nir_register *reg)
32 {
33 nir_function_impl *impl = NULL;
34
35 assert(reg->is_global);
36
37 nir_foreach_def(def_dest, reg) {
38 nir_instr *instr = def_dest->reg.parent_instr;
39 nir_function_impl *instr_impl =
40 nir_cf_node_get_function(&instr->block->cf_node);
41 if (impl != NULL) {
42 if (impl != instr_impl)
43 return false;
44 } else {
45 impl = instr_impl;
46 }
47 }
48
49 nir_foreach_use(use_src, reg) {
50 nir_instr *instr = use_src->parent_instr;
51 nir_function_impl *instr_impl =
52 nir_cf_node_get_function(&instr->block->cf_node);
53 if (impl != NULL) {
54 if (impl != instr_impl)
55 return false;
56 } else {
57 impl = instr_impl;
58 }
59 }
60
61 nir_foreach_if_use(use_src, reg) {
62 nir_if *if_stmt = use_src->parent_if;
63 nir_function_impl *if_impl = nir_cf_node_get_function(&if_stmt->cf_node);
64 if (impl != NULL) {
65 if (impl != if_impl)
66 return false;
67 } else {
68 impl = if_impl;
69 }
70 }
71
72 if (impl == NULL) {
73 /* this instruction is never used/defined, delete it */
74 nir_reg_remove(reg);
75 return true;
76 }
77
78 /*
79 * if we've gotten to this point, the register is always used/defined in
80 * the same implementation so we can move it to be local to that
81 * implementation.
82 */
83
84 exec_node_remove(®->node);
85 exec_list_push_tail(&impl->registers, ®->node);
86 reg->index = impl->reg_alloc++;
87 reg->is_global = false;
88 return true;
89 }
90
91 bool
nir_opt_global_to_local(nir_shader * shader)92 nir_opt_global_to_local(nir_shader *shader)
93 {
94 bool progress = false;
95
96 foreach_list_typed_safe(nir_register, reg, node, &shader->registers) {
97 if (global_to_local(reg))
98 progress = true;
99 }
100
101 return progress;
102 }
103