1 /*
2 * Copyright © 2022 Imagination Technologies Ltd.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * 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 THE
18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
21 * SOFTWARE.
22 */
23
24 #include "nir/nir.h"
25 #include "nir/nir_builder.h"
26 #include "nir/nir_search_helpers.h"
27 #include "rogue_constreg.h"
28 #include "rogue_nir.h"
29
30 /* TODO: optimize: if value is in const regs, replace, else, use shared regs and
31 * notify driver they need to be populated?
32 */
33
34 /* Replaces multiple ssa uses from load_const with a single use -> a register.
35 */
rogue_nir_constreg(nir_shader * shader)36 void rogue_nir_constreg(nir_shader *shader)
37 {
38 nir_function_impl *impl = nir_shader_get_entrypoint(shader);
39 nir_builder b;
40
41 nir_builder_init(&b, impl);
42
43 /* Find load_const instructions. */
44 nir_foreach_block (block, impl) {
45 nir_foreach_instr_safe (instr, block) {
46 if (instr->type != nir_instr_type_load_const)
47 continue;
48
49 nir_load_const_instr *load_const = nir_instr_as_load_const(instr);
50
51 /* Skip values that can be pulled from constant registers. */
52 uint32_t value = nir_const_value_as_uint(load_const->value[0], 32);
53 size_t const_reg = rogue_constreg_lookup(value);
54 if (const_reg != ROGUE_NO_CONST_REG)
55 continue;
56
57 b.cursor = nir_after_instr(&load_const->instr);
58 nir_ssa_def *mov = nir_mov(&b, &load_const->def);
59
60 nir_foreach_use_safe (use_src, &load_const->def) {
61 if (use_src->parent_instr == mov->parent_instr)
62 continue;
63
64 /* Skip when used as an index for intrinsics, as we want to
65 * access that value directly.
66 */
67 if (use_src->parent_instr->type == nir_instr_type_intrinsic)
68 continue;
69
70 nir_instr_rewrite_src_ssa(use_src->parent_instr, use_src, mov);
71 }
72 }
73 }
74 }
75