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_algebraic.c
26 *
27 * This is the optimization pass for miscellaneous changes to instructions
28 * where we can simplify the operation by some knowledge about the specific
29 * operations.
30 *
31 * Mostly this will be a matter of turning things into MOVs so that they can
32 * later be copy-propagated out.
33 */
34
35 #include "vc4_qir.h"
36 #include "util/u_math.h"
37
38 static bool debug;
39
40 static void
dump_from(struct vc4_compile * c,struct qinst * inst)41 dump_from(struct vc4_compile *c, struct qinst *inst)
42 {
43 if (!debug)
44 return;
45
46 fprintf(stderr, "optimizing: ");
47 qir_dump_inst(c, inst);
48 fprintf(stderr, "\n");
49 }
50
51 static void
dump_to(struct vc4_compile * c,struct qinst * inst)52 dump_to(struct vc4_compile *c, struct qinst *inst)
53 {
54 if (!debug)
55 return;
56
57 fprintf(stderr, "to: ");
58 qir_dump_inst(c, inst);
59 fprintf(stderr, "\n");
60 }
61
62 static bool
is_constant_value(struct vc4_compile * c,struct qreg reg,uint32_t val)63 is_constant_value(struct vc4_compile *c, struct qreg reg,
64 uint32_t val)
65 {
66 if (reg.file == QFILE_UNIF &&
67 !reg.pack &&
68 c->uniform_contents[reg.index] == QUNIFORM_CONSTANT &&
69 c->uniform_data[reg.index] == val) {
70 return true;
71 }
72
73 if (reg.file == QFILE_SMALL_IMM && reg.index == val)
74 return true;
75
76 return false;
77 }
78
79 static bool
is_zero(struct vc4_compile * c,struct qreg reg)80 is_zero(struct vc4_compile *c, struct qreg reg)
81 {
82 reg = qir_follow_movs(c, reg);
83 return is_constant_value(c, reg, 0);
84 }
85
86 static bool
is_1f(struct vc4_compile * c,struct qreg reg)87 is_1f(struct vc4_compile *c, struct qreg reg)
88 {
89 reg = qir_follow_movs(c, reg);
90 return is_constant_value(c, reg, fui(1.0));
91 }
92
93 static void
replace_with_mov(struct vc4_compile * c,struct qinst * inst,struct qreg arg)94 replace_with_mov(struct vc4_compile *c, struct qinst *inst, struct qreg arg)
95 {
96 dump_from(c, inst);
97
98 inst->src[0] = arg;
99 if (qir_has_implicit_tex_uniform(inst))
100 inst->src[1] = inst->src[qir_get_tex_uniform_src(inst)];
101
102 if (qir_is_mul(inst))
103 inst->op = QOP_MMOV;
104 else if (qir_is_float_input(inst))
105 inst->op = QOP_FMOV;
106 else
107 inst->op = QOP_MOV;
108 dump_to(c, inst);
109 }
110
111 static bool
replace_x_0_with_x(struct vc4_compile * c,struct qinst * inst,int arg)112 replace_x_0_with_x(struct vc4_compile *c,
113 struct qinst *inst,
114 int arg)
115 {
116 if (!is_zero(c, inst->src[arg]))
117 return false;
118 replace_with_mov(c, inst, inst->src[1 - arg]);
119 return true;
120 }
121
122 static bool
replace_x_0_with_0(struct vc4_compile * c,struct qinst * inst,int arg)123 replace_x_0_with_0(struct vc4_compile *c,
124 struct qinst *inst,
125 int arg)
126 {
127 if (!is_zero(c, inst->src[arg]))
128 return false;
129 replace_with_mov(c, inst, inst->src[arg]);
130 return true;
131 }
132
133 static bool
fmul_replace_one(struct vc4_compile * c,struct qinst * inst,int arg)134 fmul_replace_one(struct vc4_compile *c,
135 struct qinst *inst,
136 int arg)
137 {
138 if (!is_1f(c, inst->src[arg]))
139 return false;
140 replace_with_mov(c, inst, inst->src[1 - arg]);
141 return true;
142 }
143
144 bool
qir_opt_algebraic(struct vc4_compile * c)145 qir_opt_algebraic(struct vc4_compile *c)
146 {
147 bool progress = false;
148
149 qir_for_each_inst_inorder(inst, c) {
150 switch (inst->op) {
151 case QOP_FMIN:
152 if (is_1f(c, inst->src[1]) &&
153 inst->src[0].pack >= QPU_UNPACK_8D_REP &&
154 inst->src[0].pack <= QPU_UNPACK_8D) {
155 replace_with_mov(c, inst, inst->src[0]);
156 progress = true;
157 }
158 break;
159
160 case QOP_FMAX:
161 if (is_zero(c, inst->src[1]) &&
162 inst->src[0].pack >= QPU_UNPACK_8D_REP &&
163 inst->src[0].pack <= QPU_UNPACK_8D) {
164 replace_with_mov(c, inst, inst->src[0]);
165 progress = true;
166 }
167 break;
168
169 case QOP_FSUB:
170 case QOP_SUB:
171 if (is_zero(c, inst->src[1])) {
172 replace_with_mov(c, inst, inst->src[0]);
173 progress = true;
174 }
175 break;
176
177 case QOP_ADD:
178 /* Kernel validation requires that we use an actual
179 * add instruction.
180 */
181 if (inst->dst.file != QFILE_TEX_S_DIRECT &&
182 (replace_x_0_with_x(c, inst, 0) ||
183 replace_x_0_with_x(c, inst, 1))) {
184 progress = true;
185 break;
186 }
187 break;
188
189 case QOP_FADD:
190 if (replace_x_0_with_x(c, inst, 0) ||
191 replace_x_0_with_x(c, inst, 1)) {
192 progress = true;
193 break;
194 }
195
196 /* FADD(a, FSUB(0, b)) -> FSUB(a, b) */
197 if (inst->src[1].file == QFILE_TEMP &&
198 c->defs[inst->src[1].index] &&
199 c->defs[inst->src[1].index]->op == QOP_FSUB) {
200 struct qinst *fsub = c->defs[inst->src[1].index];
201 if (is_zero(c, fsub->src[0])) {
202 dump_from(c, inst);
203 inst->op = QOP_FSUB;
204 inst->src[1] = fsub->src[1];
205 progress = true;
206 dump_to(c, inst);
207 break;
208 }
209 }
210
211 /* FADD(FSUB(0, b), a) -> FSUB(a, b) */
212 if (inst->src[0].file == QFILE_TEMP &&
213 c->defs[inst->src[0].index] &&
214 c->defs[inst->src[0].index]->op == QOP_FSUB) {
215 struct qinst *fsub = c->defs[inst->src[0].index];
216 if (is_zero(c, fsub->src[0])) {
217 dump_from(c, inst);
218 inst->op = QOP_FSUB;
219 inst->src[0] = inst->src[1];
220 inst->src[1] = fsub->src[1];
221 dump_to(c, inst);
222 progress = true;
223 break;
224 }
225 }
226 break;
227
228 case QOP_FMUL:
229 if (!inst->dst.pack &&
230 (replace_x_0_with_0(c, inst, 0) ||
231 replace_x_0_with_0(c, inst, 1) ||
232 fmul_replace_one(c, inst, 0) ||
233 fmul_replace_one(c, inst, 1))) {
234 progress = true;
235 break;
236 }
237 break;
238
239 case QOP_MUL24:
240 if (!inst->dst.pack &&
241 (replace_x_0_with_0(c, inst, 0) ||
242 replace_x_0_with_0(c, inst, 1))) {
243 progress = true;
244 break;
245 }
246 break;
247
248 case QOP_AND:
249 if (replace_x_0_with_0(c, inst, 0) ||
250 replace_x_0_with_0(c, inst, 1)) {
251 progress = true;
252 break;
253 }
254
255 if (is_constant_value(c, inst->src[0], ~0)) {
256 replace_with_mov(c, inst, inst->src[1]);
257 progress = true;
258 break;
259 }
260 if (is_constant_value(c, inst->src[1], ~0)) {
261 replace_with_mov(c, inst, inst->src[0]);
262 progress = true;
263 break;
264 }
265 break;
266
267 case QOP_OR:
268 if (replace_x_0_with_x(c, inst, 0) ||
269 replace_x_0_with_x(c, inst, 1)) {
270 progress = true;
271 break;
272 }
273 break;
274
275 case QOP_RCP:
276 if (is_1f(c, inst->src[0])) {
277 replace_with_mov(c, inst, inst->src[0]);
278 progress = true;
279 break;
280 }
281 break;
282
283 default:
284 break;
285 }
286 }
287
288 return progress;
289 }
290