1 /*
2 * Copyright © 2014 Broadcom
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
24 /**
25 * @file vc4_opt_coalesce_ff_writes.c
26 *
27 * This modifies instructions that generate the value consumed by a VPM or TMU
28 * coordinate write to write directly into the VPM or TMU.
29 */
30
31 #include "vc4_qir.h"
32
33 bool
qir_opt_coalesce_ff_writes(struct vc4_compile * c)34 qir_opt_coalesce_ff_writes(struct vc4_compile *c)
35 {
36 /* For now, only do this pass when we don't have control flow. */
37 struct qblock *block = qir_entry_block(c);
38 if (block != qir_exit_block(c))
39 return false;
40
41 bool progress = false;
42 uint32_t use_count[c->num_temps];
43 memset(&use_count, 0, sizeof(use_count));
44
45 qir_for_each_inst_inorder(inst, c) {
46 for (int i = 0; i < qir_get_nsrc(inst); i++) {
47 if (inst->src[i].file == QFILE_TEMP) {
48 uint32_t temp = inst->src[i].index;
49 use_count[temp]++;
50 }
51 }
52 }
53
54 qir_for_each_inst_inorder(mov_inst, c) {
55 if (!qir_is_raw_mov(mov_inst) || mov_inst->sf)
56 continue;
57 if (mov_inst->src[0].file != QFILE_TEMP)
58 continue;
59
60 if (!(mov_inst->dst.file == QFILE_VPM || qir_is_tex(mov_inst)))
61 continue;
62
63 uint32_t temp = mov_inst->src[0].index;
64 if (use_count[temp] != 1)
65 continue;
66
67 struct qinst *inst = c->defs[temp];
68 if (!inst)
69 continue;
70
71 /* Don't bother trying to fold in an ALU op using a uniform to
72 * a texture op, as we'll just have to lower the uniform back
73 * out.
74 */
75 if (qir_is_tex(mov_inst) && qir_has_uniform_read(inst))
76 continue;
77
78 if (qir_depends_on_flags(inst) || inst->sf)
79 continue;
80
81 if (qir_has_side_effects(c, inst) ||
82 qir_has_side_effect_reads(c, inst) ||
83 inst->op == QOP_VARY_ADD_C) {
84 continue;
85 }
86
87 /* Move the generating instruction into the position of the FF
88 * write.
89 */
90 c->defs[inst->dst.index] = NULL;
91 inst->dst.file = mov_inst->dst.file;
92 inst->dst.index = mov_inst->dst.index;
93 if (qir_has_implicit_tex_uniform(mov_inst)) {
94 inst->src[qir_get_tex_uniform_src(inst)] =
95 mov_inst->src[qir_get_tex_uniform_src(mov_inst)];
96 }
97
98 list_del(&inst->link);
99 list_addtail(&inst->link, &mov_inst->link);
100
101 qir_remove_instruction(c, mov_inst);
102
103 progress = true;
104 }
105
106 return progress;
107 }
108