Revert "intel/compiler: split is_partial_write() into two variants"
[mesa.git] / src / intel / compiler / brw_fs_cse.cpp
1 /*
2 * Copyright © 2012 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
24 #include "brw_fs.h"
25 #include "brw_cfg.h"
26
27 /** @file brw_fs_cse.cpp
28 *
29 * Support for local common subexpression elimination.
30 *
31 * See Muchnick's Advanced Compiler Design and Implementation, section
32 * 13.1 (p378).
33 */
34
35 using namespace brw;
36
37 namespace {
38 struct aeb_entry : public exec_node {
39 /** The instruction that generates the expression value. */
40 fs_inst *generator;
41
42 /** The temporary where the value is stored. */
43 fs_reg tmp;
44 };
45 }
46
47 static bool
48 is_expression(const fs_visitor *v, const fs_inst *const inst)
49 {
50 switch (inst->opcode) {
51 case BRW_OPCODE_MOV:
52 case BRW_OPCODE_SEL:
53 case BRW_OPCODE_NOT:
54 case BRW_OPCODE_AND:
55 case BRW_OPCODE_OR:
56 case BRW_OPCODE_XOR:
57 case BRW_OPCODE_SHR:
58 case BRW_OPCODE_SHL:
59 case BRW_OPCODE_ASR:
60 case BRW_OPCODE_CMP:
61 case BRW_OPCODE_CMPN:
62 case BRW_OPCODE_ADD:
63 case BRW_OPCODE_MUL:
64 case SHADER_OPCODE_MULH:
65 case BRW_OPCODE_FRC:
66 case BRW_OPCODE_RNDU:
67 case BRW_OPCODE_RNDD:
68 case BRW_OPCODE_RNDE:
69 case BRW_OPCODE_RNDZ:
70 case BRW_OPCODE_LINE:
71 case BRW_OPCODE_PLN:
72 case BRW_OPCODE_MAD:
73 case BRW_OPCODE_LRP:
74 case FS_OPCODE_FB_READ_LOGICAL:
75 case FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD:
76 case FS_OPCODE_VARYING_PULL_CONSTANT_LOAD_LOGICAL:
77 case FS_OPCODE_LINTERP:
78 case SHADER_OPCODE_FIND_LIVE_CHANNEL:
79 case SHADER_OPCODE_BROADCAST:
80 case SHADER_OPCODE_MOV_INDIRECT:
81 case SHADER_OPCODE_TEX_LOGICAL:
82 case SHADER_OPCODE_TXD_LOGICAL:
83 case SHADER_OPCODE_TXF_LOGICAL:
84 case SHADER_OPCODE_TXL_LOGICAL:
85 case SHADER_OPCODE_TXS_LOGICAL:
86 case FS_OPCODE_TXB_LOGICAL:
87 case SHADER_OPCODE_TXF_CMS_LOGICAL:
88 case SHADER_OPCODE_TXF_CMS_W_LOGICAL:
89 case SHADER_OPCODE_TXF_UMS_LOGICAL:
90 case SHADER_OPCODE_TXF_MCS_LOGICAL:
91 case SHADER_OPCODE_LOD_LOGICAL:
92 case SHADER_OPCODE_TG4_LOGICAL:
93 case SHADER_OPCODE_TG4_OFFSET_LOGICAL:
94 case FS_OPCODE_PACK:
95 return true;
96 case SHADER_OPCODE_RCP:
97 case SHADER_OPCODE_RSQ:
98 case SHADER_OPCODE_SQRT:
99 case SHADER_OPCODE_EXP2:
100 case SHADER_OPCODE_LOG2:
101 case SHADER_OPCODE_POW:
102 case SHADER_OPCODE_INT_QUOTIENT:
103 case SHADER_OPCODE_INT_REMAINDER:
104 case SHADER_OPCODE_SIN:
105 case SHADER_OPCODE_COS:
106 return inst->mlen < 2;
107 case SHADER_OPCODE_LOAD_PAYLOAD:
108 return !inst->is_copy_payload(v->alloc);
109 default:
110 return inst->is_send_from_grf() && !inst->has_side_effects() &&
111 !inst->is_volatile();
112 }
113 }
114
115 static bool
116 operands_match(const fs_inst *a, const fs_inst *b, bool *negate)
117 {
118 fs_reg *xs = a->src;
119 fs_reg *ys = b->src;
120
121 if (a->opcode == BRW_OPCODE_MAD) {
122 return xs[0].equals(ys[0]) &&
123 ((xs[1].equals(ys[1]) && xs[2].equals(ys[2])) ||
124 (xs[2].equals(ys[1]) && xs[1].equals(ys[2])));
125 } else if (a->opcode == BRW_OPCODE_MUL && a->dst.type == BRW_REGISTER_TYPE_F) {
126 bool xs0_negate = xs[0].negate;
127 bool xs1_negate = xs[1].file == IMM ? xs[1].f < 0.0f
128 : xs[1].negate;
129 bool ys0_negate = ys[0].negate;
130 bool ys1_negate = ys[1].file == IMM ? ys[1].f < 0.0f
131 : ys[1].negate;
132 float xs1_imm = xs[1].f;
133 float ys1_imm = ys[1].f;
134
135 xs[0].negate = false;
136 xs[1].negate = false;
137 ys[0].negate = false;
138 ys[1].negate = false;
139 xs[1].f = fabsf(xs[1].f);
140 ys[1].f = fabsf(ys[1].f);
141
142 bool ret = (xs[0].equals(ys[0]) && xs[1].equals(ys[1])) ||
143 (xs[1].equals(ys[0]) && xs[0].equals(ys[1]));
144
145 xs[0].negate = xs0_negate;
146 xs[1].negate = xs[1].file == IMM ? false : xs1_negate;
147 ys[0].negate = ys0_negate;
148 ys[1].negate = ys[1].file == IMM ? false : ys1_negate;
149 xs[1].f = xs1_imm;
150 ys[1].f = ys1_imm;
151
152 *negate = (xs0_negate != xs1_negate) != (ys0_negate != ys1_negate);
153 if (*negate && (a->saturate || b->saturate))
154 return false;
155 return ret;
156 } else if (!a->is_commutative()) {
157 bool match = true;
158 for (int i = 0; i < a->sources; i++) {
159 if (!xs[i].equals(ys[i])) {
160 match = false;
161 break;
162 }
163 }
164 return match;
165 } else {
166 return (xs[0].equals(ys[0]) && xs[1].equals(ys[1])) ||
167 (xs[1].equals(ys[0]) && xs[0].equals(ys[1]));
168 }
169 }
170
171 static bool
172 instructions_match(fs_inst *a, fs_inst *b, bool *negate)
173 {
174 return a->opcode == b->opcode &&
175 a->force_writemask_all == b->force_writemask_all &&
176 a->exec_size == b->exec_size &&
177 a->group == b->group &&
178 a->saturate == b->saturate &&
179 a->predicate == b->predicate &&
180 a->predicate_inverse == b->predicate_inverse &&
181 a->conditional_mod == b->conditional_mod &&
182 a->flag_subreg == b->flag_subreg &&
183 a->dst.type == b->dst.type &&
184 a->offset == b->offset &&
185 a->mlen == b->mlen &&
186 a->ex_mlen == b->ex_mlen &&
187 a->sfid == b->sfid &&
188 a->desc == b->desc &&
189 a->size_written == b->size_written &&
190 a->base_mrf == b->base_mrf &&
191 a->check_tdr == b->check_tdr &&
192 a->send_has_side_effects == b->send_has_side_effects &&
193 a->eot == b->eot &&
194 a->header_size == b->header_size &&
195 a->shadow_compare == b->shadow_compare &&
196 a->pi_noperspective == b->pi_noperspective &&
197 a->target == b->target &&
198 a->sources == b->sources &&
199 operands_match(a, b, negate);
200 }
201
202 static void
203 create_copy_instr(const fs_builder &bld, fs_inst *inst, fs_reg src, bool negate)
204 {
205 unsigned written = regs_written(inst);
206 unsigned dst_width =
207 DIV_ROUND_UP(inst->dst.component_size(inst->exec_size), REG_SIZE);
208 fs_inst *copy;
209
210 if (inst->opcode == SHADER_OPCODE_LOAD_PAYLOAD) {
211 assert(src.file == VGRF);
212 fs_reg *payload = ralloc_array(bld.shader->mem_ctx, fs_reg,
213 inst->sources);
214 for (int i = 0; i < inst->header_size; i++) {
215 payload[i] = src;
216 src.offset += REG_SIZE;
217 }
218 for (int i = inst->header_size; i < inst->sources; i++) {
219 src.type = inst->src[i].type;
220 payload[i] = src;
221 src = offset(src, bld, 1);
222 }
223 copy = bld.LOAD_PAYLOAD(inst->dst, payload, inst->sources,
224 inst->header_size);
225 } else if (written != dst_width) {
226 assert(src.file == VGRF);
227 assert(written % dst_width == 0);
228 const int sources = written / dst_width;
229 fs_reg *payload = ralloc_array(bld.shader->mem_ctx, fs_reg, sources);
230 for (int i = 0; i < sources; i++) {
231 payload[i] = src;
232 src = offset(src, bld, 1);
233 }
234 copy = bld.LOAD_PAYLOAD(inst->dst, payload, sources, 0);
235 } else {
236 copy = bld.MOV(inst->dst, src);
237 copy->group = inst->group;
238 copy->force_writemask_all = inst->force_writemask_all;
239 copy->src[0].negate = negate;
240 }
241 assert(regs_written(copy) == written);
242 }
243
244 bool
245 fs_visitor::opt_cse_local(bblock_t *block)
246 {
247 bool progress = false;
248 exec_list aeb;
249
250 void *cse_ctx = ralloc_context(NULL);
251
252 int ip = block->start_ip;
253 foreach_inst_in_block(fs_inst, inst, block) {
254 /* Skip some cases. */
255 if (is_expression(this, inst) && !inst->is_partial_write() &&
256 ((inst->dst.file != ARF && inst->dst.file != FIXED_GRF) ||
257 inst->dst.is_null()))
258 {
259 bool found = false;
260 bool negate = false;
261
262 foreach_in_list_use_after(aeb_entry, entry, &aeb) {
263 /* Match current instruction's expression against those in AEB. */
264 if (!(entry->generator->dst.is_null() && !inst->dst.is_null()) &&
265 instructions_match(inst, entry->generator, &negate)) {
266 found = true;
267 progress = true;
268 break;
269 }
270 }
271
272 if (!found) {
273 if (inst->opcode != BRW_OPCODE_MOV ||
274 (inst->opcode == BRW_OPCODE_MOV &&
275 inst->src[0].file == IMM &&
276 inst->src[0].type == BRW_REGISTER_TYPE_VF)) {
277 /* Our first sighting of this expression. Create an entry. */
278 aeb_entry *entry = ralloc(cse_ctx, aeb_entry);
279 entry->tmp = reg_undef;
280 entry->generator = inst;
281 aeb.push_tail(entry);
282 }
283 } else {
284 /* This is at least our second sighting of this expression.
285 * If we don't have a temporary already, make one.
286 */
287 bool no_existing_temp = entry->tmp.file == BAD_FILE;
288 if (no_existing_temp && !entry->generator->dst.is_null()) {
289 const fs_builder ibld = fs_builder(this, block, entry->generator)
290 .at(block, entry->generator->next);
291 int written = regs_written(entry->generator);
292
293 entry->tmp = fs_reg(VGRF, alloc.allocate(written),
294 entry->generator->dst.type);
295
296 create_copy_instr(ibld, entry->generator, entry->tmp, false);
297
298 entry->generator->dst = entry->tmp;
299 }
300
301 /* dest <- temp */
302 if (!inst->dst.is_null()) {
303 assert(inst->size_written == entry->generator->size_written);
304 assert(inst->dst.type == entry->tmp.type);
305 const fs_builder ibld(this, block, inst);
306
307 create_copy_instr(ibld, inst, entry->tmp, negate);
308 }
309
310 /* Set our iterator so that next time through the loop inst->next
311 * will get the instruction in the basic block after the one we've
312 * removed.
313 */
314 fs_inst *prev = (fs_inst *)inst->prev;
315
316 inst->remove(block);
317 inst = prev;
318 }
319 }
320
321 foreach_in_list_safe(aeb_entry, entry, &aeb) {
322 /* Kill all AEB entries that write a different value to or read from
323 * the flag register if we just wrote it.
324 */
325 if (inst->flags_written()) {
326 bool negate; /* dummy */
327 if (entry->generator->flags_read(devinfo) ||
328 (entry->generator->flags_written() &&
329 !instructions_match(inst, entry->generator, &negate))) {
330 entry->remove();
331 ralloc_free(entry);
332 continue;
333 }
334 }
335
336 for (int i = 0; i < entry->generator->sources; i++) {
337 fs_reg *src_reg = &entry->generator->src[i];
338
339 /* Kill all AEB entries that use the destination we just
340 * overwrote.
341 */
342 if (regions_overlap(inst->dst, inst->size_written,
343 entry->generator->src[i],
344 entry->generator->size_read(i))) {
345 entry->remove();
346 ralloc_free(entry);
347 break;
348 }
349
350 /* Kill any AEB entries using registers that don't get reused any
351 * more -- a sure sign they'll fail operands_match().
352 */
353 if (src_reg->file == VGRF && virtual_grf_end[src_reg->nr] < ip) {
354 entry->remove();
355 ralloc_free(entry);
356 break;
357 }
358 }
359 }
360
361 ip++;
362 }
363
364 ralloc_free(cse_ctx);
365
366 return progress;
367 }
368
369 bool
370 fs_visitor::opt_cse()
371 {
372 bool progress = false;
373
374 calculate_live_intervals();
375
376 foreach_block (block, cfg) {
377 progress = opt_cse_local(block) || progress;
378 }
379
380 if (progress)
381 invalidate_live_intervals();
382
383 return progress;
384 }