1 /*
2 * Copyright (C) 2021 Collabora, Ltd.
3 * Copyright (C) 2014 Valve Corporation
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 */
24
25 #include "bi_builder.h"
26 #include "compiler.h"
27
28 #define XXH_INLINE_ALL
29 #include "util/xxhash.h"
30
31 /* This pass handles CSE'ing repeated expressions created in the process of
32 * translating from NIR. Also, currently this is intra-block only, to make it
33 * work over multiple block we'd need to bring forward dominance calculation.
34 */
35
36 static inline uint32_t
HASH(uint32_t hash,unsigned data)37 HASH(uint32_t hash, unsigned data)
38 {
39 return XXH32(&data, sizeof(data), hash);
40 }
41
42 static uint32_t
hash_index(uint32_t hash,bi_index index)43 hash_index(uint32_t hash, bi_index index)
44 {
45 hash = HASH(hash, index.value);
46 hash = HASH(hash, index.abs);
47 hash = HASH(hash, index.neg);
48 hash = HASH(hash, index.swizzle);
49 hash = HASH(hash, index.offset);
50 hash = HASH(hash, index.type);
51 return hash;
52 }
53
54 /* Hash an ALU instruction. */
55 static uint32_t
hash_instr(const void * data)56 hash_instr(const void *data)
57 {
58 const bi_instr *I = data;
59 uint32_t hash = 0;
60
61 hash = HASH(hash, I->op);
62 hash = HASH(hash, I->nr_dests);
63 hash = HASH(hash, I->nr_srcs);
64
65 assert(!I->flow && !I->slot && "CSE must be early");
66
67 /* Explcitly skip destinations, except for size details */
68 bi_foreach_dest(I, d) {
69 hash = HASH(hash, I->dest[d].swizzle);
70 }
71
72 bi_foreach_src(I, s) {
73 hash = hash_index(hash, I->src[s]);
74 }
75
76 /* Explicitly skip branch, regfmt, vecsize, no_spill, tdd, table */
77 hash = HASH(hash, I->dest_mod);
78
79 /* Explicitly skip other immediates */
80 hash = HASH(hash, I->shift);
81
82 for (unsigned i = 0; i < ARRAY_SIZE(I->flags); ++i)
83 hash = HASH(hash, I->flags[i]);
84
85 return hash;
86 }
87
88 static bool
instrs_equal(const void * _i1,const void * _i2)89 instrs_equal(const void *_i1, const void *_i2)
90 {
91 const bi_instr *i1 = _i1, *i2 = _i2;
92
93 if (i1->op != i2->op)
94 return false;
95 if (i1->nr_srcs != i2->nr_srcs)
96 return false;
97 if (i1->nr_dests != i2->nr_dests)
98 return false;
99
100 /* Explicitly skip destinations */
101
102 bi_foreach_src(i1, s) {
103 bi_index s1 = i1->src[s], s2 = i2->src[s];
104
105 if (memcmp(&s1, &s2, sizeof(s1)) != 0)
106 return false;
107 }
108
109 if (i1->dest_mod != i2->dest_mod)
110 return false;
111
112 if (i1->shift != i2->shift)
113 return false;
114
115 for (unsigned i = 0; i < ARRAY_SIZE(i1->flags); ++i) {
116 if (i1->flags[i] != i2->flags[i])
117 return false;
118 }
119
120 return true;
121 }
122
123 /* Determines what instructions the above routines have to handle */
124
125 static bool
instr_can_cse(const bi_instr * I)126 instr_can_cse(const bi_instr *I)
127 {
128 switch (I->op) {
129 case BI_OPCODE_DTSEL_IMM:
130 case BI_OPCODE_DISCARD_F32:
131 return false;
132 default:
133 break;
134 }
135
136 /* Be conservative about which message-passing instructions we CSE,
137 * since most are not pure even within a thread.
138 */
139 if (bi_opcode_props[I->op].message && I->op != BI_OPCODE_LEA_BUF_IMM)
140 return false;
141
142 if (I->branch_target)
143 return false;
144
145 return true;
146 }
147
148 void
bi_opt_cse(bi_context * ctx)149 bi_opt_cse(bi_context *ctx)
150 {
151 struct set *instr_set = _mesa_set_create(NULL, hash_instr, instrs_equal);
152 bi_index *replacement = calloc(sizeof(bi_index), ctx->ssa_alloc);
153
154 bi_foreach_block(ctx, block) {
155 _mesa_set_clear(instr_set, NULL);
156
157 bi_foreach_instr_in_block(block, instr) {
158 /* Rewrite before trying to CSE anything so we converge
159 * locally in one iteration */
160 bi_foreach_ssa_src(instr, s) {
161 if (bi_is_staging_src(instr, s))
162 continue;
163
164 bi_index repl = replacement[instr->src[s].value];
165 if (!bi_is_null(repl))
166 bi_replace_src(instr, s, repl);
167 }
168
169 if (!instr_can_cse(instr))
170 continue;
171
172 bool found;
173 struct set_entry *entry =
174 _mesa_set_search_or_add(instr_set, instr, &found);
175 if (found) {
176 const bi_instr *match = entry->key;
177
178 bi_foreach_dest(instr, d) {
179 replacement[instr->dest[d].value] = match->dest[d];
180 }
181 }
182 }
183 }
184
185 free(replacement);
186 _mesa_set_destroy(instr_set, NULL);
187 }
188