1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
|
/*
* Copyright © 2016 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "nir.h"
#include "nir_builder.h"
#include "nir_deref.h"
#include "util/bitscan.h"
#include "util/u_dynarray.h"
static const bool debug = false;
/**
* Variable-based copy propagation
*
* Normally, NIR trusts in SSA form for most of its copy-propagation needs.
* However, there are cases, especially when dealing with indirects, where SSA
* won't help you. This pass is for those times. Specifically, it handles
* the following things that the rest of NIR can't:
*
* 1) Copy-propagation on variables that have indirect access. This includes
* propagating from indirect stores into indirect loads.
*
* 2) Removal of redundant load_deref intrinsics. We can't trust regular CSE
* to do this because it isn't aware of variable writes that may alias the
* value and make the former load invalid.
*
* This pass uses an intermediate solution between being local / "per-block"
* and a complete data-flow analysis. It follows the control flow graph, and
* propagate the available copy information forward, invalidating data at each
* cf_node.
*
* Removal of dead writes to variables is handled by another pass.
*/
struct vars_written {
nir_variable_mode modes;
/* Key is deref and value is the uintptr_t with the write mask. */
struct hash_table *derefs;
};
struct value {
bool is_ssa;
union {
struct {
nir_ssa_def *def[NIR_MAX_VEC_COMPONENTS];
uint8_t component[NIR_MAX_VEC_COMPONENTS];
} ssa;
nir_deref_instr *deref;
};
};
static void
value_set_ssa_components(struct value *value, nir_ssa_def *def,
unsigned num_components)
{
if (!value->is_ssa)
memset(&value->ssa, 0, sizeof(value->ssa));
value->is_ssa = true;
for (unsigned i = 0; i < num_components; i++) {
value->ssa.def[i] = def;
value->ssa.component[i] = i;
}
}
struct copy_entry {
struct value src;
nir_deref_instr *dst;
};
struct copy_prop_var_state {
nir_function_impl *impl;
void *mem_ctx;
void *lin_ctx;
/* Maps nodes to vars_written. Used to invalidate copy entries when
* visiting each node.
*/
struct hash_table *vars_written_map;
bool progress;
};
static bool
value_equals_store_src(struct value *value, nir_intrinsic_instr *intrin)
{
assert(intrin->intrinsic == nir_intrinsic_store_deref);
uintptr_t write_mask = nir_intrinsic_write_mask(intrin);
for (unsigned i = 0; i < intrin->num_components; i++) {
if ((write_mask & (1 << i)) &&
(value->ssa.def[i] != intrin->src[1].ssa ||
value->ssa.component[i] != i))
return false;
}
return true;
}
static struct vars_written *
create_vars_written(struct copy_prop_var_state *state)
{
struct vars_written *written =
linear_zalloc_child(state->lin_ctx, sizeof(struct vars_written));
written->derefs = _mesa_pointer_hash_table_create(state->mem_ctx);
return written;
}
static void
gather_vars_written(struct copy_prop_var_state *state,
struct vars_written *written,
nir_cf_node *cf_node)
{
struct vars_written *new_written = NULL;
switch (cf_node->type) {
case nir_cf_node_function: {
nir_function_impl *impl = nir_cf_node_as_function(cf_node);
foreach_list_typed_safe(nir_cf_node, cf_node, node, &impl->body)
gather_vars_written(state, NULL, cf_node);
break;
}
case nir_cf_node_block: {
if (!written)
break;
nir_block *block = nir_cf_node_as_block(cf_node);
nir_foreach_instr(instr, block) {
if (instr->type == nir_instr_type_call) {
written->modes |= nir_var_shader_out |
nir_var_shader_temp |
nir_var_function_temp |
nir_var_mem_ssbo |
nir_var_mem_shared;
continue;
}
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
switch (intrin->intrinsic) {
case nir_intrinsic_barrier:
case nir_intrinsic_memory_barrier:
written->modes |= nir_var_shader_out |
nir_var_mem_ssbo |
nir_var_mem_shared;
break;
case nir_intrinsic_emit_vertex:
case nir_intrinsic_emit_vertex_with_counter:
written->modes = nir_var_shader_out;
break;
case nir_intrinsic_deref_atomic_add:
case nir_intrinsic_deref_atomic_imin:
case nir_intrinsic_deref_atomic_umin:
case nir_intrinsic_deref_atomic_imax:
case nir_intrinsic_deref_atomic_umax:
case nir_intrinsic_deref_atomic_and:
case nir_intrinsic_deref_atomic_or:
case nir_intrinsic_deref_atomic_xor:
case nir_intrinsic_deref_atomic_exchange:
case nir_intrinsic_deref_atomic_comp_swap:
case nir_intrinsic_store_deref:
case nir_intrinsic_copy_deref: {
/* Destination in all of store_deref, copy_deref and the atomics is src[0]. */
nir_deref_instr *dst = nir_src_as_deref(intrin->src[0]);
uintptr_t mask = intrin->intrinsic == nir_intrinsic_store_deref ?
nir_intrinsic_write_mask(intrin) : (1 << glsl_get_vector_elements(dst->type)) - 1;
struct hash_entry *ht_entry = _mesa_hash_table_search(written->derefs, dst);
if (ht_entry)
ht_entry->data = (void *)(mask | (uintptr_t)ht_entry->data);
else
_mesa_hash_table_insert(written->derefs, dst, (void *)mask);
break;
}
default:
break;
}
}
break;
}
case nir_cf_node_if: {
nir_if *if_stmt = nir_cf_node_as_if(cf_node);
new_written = create_vars_written(state);
foreach_list_typed_safe(nir_cf_node, cf_node, node, &if_stmt->then_list)
gather_vars_written(state, new_written, cf_node);
foreach_list_typed_safe(nir_cf_node, cf_node, node, &if_stmt->else_list)
gather_vars_written(state, new_written, cf_node);
break;
}
case nir_cf_node_loop: {
nir_loop *loop = nir_cf_node_as_loop(cf_node);
new_written = create_vars_written(state);
foreach_list_typed_safe(nir_cf_node, cf_node, node, &loop->body)
gather_vars_written(state, new_written, cf_node);
break;
}
default:
unreachable("Invalid CF node type");
}
if (new_written) {
/* Merge new information to the parent control flow node. */
if (written) {
written->modes |= new_written->modes;
hash_table_foreach(new_written->derefs, new_entry) {
struct hash_entry *old_entry =
_mesa_hash_table_search_pre_hashed(written->derefs, new_entry->hash,
new_entry->key);
if (old_entry) {
nir_component_mask_t merged = (uintptr_t) new_entry->data |
(uintptr_t) old_entry->data;
old_entry->data = (void *) ((uintptr_t) merged);
} else {
_mesa_hash_table_insert_pre_hashed(written->derefs, new_entry->hash,
new_entry->key, new_entry->data);
}
}
}
_mesa_hash_table_insert(state->vars_written_map, cf_node, new_written);
}
}
static struct copy_entry *
copy_entry_create(struct util_dynarray *copies,
nir_deref_instr *dst_deref)
{
struct copy_entry new_entry = {
.dst = dst_deref,
};
util_dynarray_append(copies, struct copy_entry, new_entry);
return util_dynarray_top_ptr(copies, struct copy_entry);
}
/* Remove copy entry by swapping it with the last element and reducing the
* size. If used inside an iteration on copies, it must be a reverse
* (backwards) iteration. It is safe to use in those cases because the swap
* will not affect the rest of the iteration.
*/
static void
copy_entry_remove(struct util_dynarray *copies,
struct copy_entry *entry)
{
/* This also works when removing the last element since pop don't shrink
* the memory used by the array, so the swap is useless but not invalid.
*/
*entry = util_dynarray_pop(copies, struct copy_entry);
}
static bool
is_array_deref_of_vector(nir_deref_instr *deref)
{
if (deref->deref_type != nir_deref_type_array)
return false;
nir_deref_instr *parent = nir_deref_instr_parent(deref);
return glsl_type_is_vector(parent->type);
}
static struct copy_entry *
lookup_entry_for_deref(struct util_dynarray *copies,
nir_deref_instr *deref,
nir_deref_compare_result allowed_comparisons)
{
struct copy_entry *entry = NULL;
util_dynarray_foreach(copies, struct copy_entry, iter) {
nir_deref_compare_result result = nir_compare_derefs(iter->dst, deref);
if (result & allowed_comparisons) {
entry = iter;
if (result & nir_derefs_equal_bit)
break;
/* Keep looking in case we have an equal match later in the array. */
}
}
return entry;
}
static struct copy_entry *
lookup_entry_and_kill_aliases(struct util_dynarray *copies,
nir_deref_instr *deref,
unsigned write_mask)
{
/* TODO: Take into account the write_mask. */
nir_deref_instr *dst_match = NULL;
util_dynarray_foreach_reverse(copies, struct copy_entry, iter) {
if (!iter->src.is_ssa) {
/* If this write aliases the source of some entry, get rid of it */
if (nir_compare_derefs(iter->src.deref, deref) & nir_derefs_may_alias_bit) {
copy_entry_remove(copies, iter);
continue;
}
}
nir_deref_compare_result comp = nir_compare_derefs(iter->dst, deref);
if (comp & nir_derefs_equal_bit) {
/* Removing entries invalidate previous iter pointers, so we'll
* collect the matching entry later. Just make sure it is unique.
*/
assert(!dst_match);
dst_match = iter->dst;
} else if (comp & nir_derefs_may_alias_bit) {
copy_entry_remove(copies, iter);
}
}
struct copy_entry *entry = NULL;
if (dst_match) {
util_dynarray_foreach(copies, struct copy_entry, iter) {
if (iter->dst == dst_match) {
entry = iter;
break;
}
}
assert(entry);
}
return entry;
}
static void
kill_aliases(struct util_dynarray *copies,
nir_deref_instr *deref,
unsigned write_mask)
{
/* TODO: Take into account the write_mask. */
struct copy_entry *entry =
lookup_entry_and_kill_aliases(copies, deref, write_mask);
if (entry)
copy_entry_remove(copies, entry);
}
static struct copy_entry *
get_entry_and_kill_aliases(struct util_dynarray *copies,
nir_deref_instr *deref,
unsigned write_mask)
{
/* TODO: Take into account the write_mask. */
struct copy_entry *entry =
lookup_entry_and_kill_aliases(copies, deref, write_mask);
if (entry == NULL)
entry = copy_entry_create(copies, deref);
return entry;
}
static void
apply_barrier_for_modes(struct util_dynarray *copies,
nir_variable_mode modes)
{
util_dynarray_foreach_reverse(copies, struct copy_entry, iter) {
if ((iter->dst->mode & modes) ||
(!iter->src.is_ssa && (iter->src.deref->mode & modes)))
copy_entry_remove(copies, iter);
}
}
static void
value_set_from_value(struct value *value, const struct value *from,
unsigned base_index, unsigned write_mask)
{
/* We can't have non-zero indexes with non-trivial write masks */
assert(base_index == 0 || write_mask == 1);
if (from->is_ssa) {
/* Clear value if it was being used as non-SSA. */
if (!value->is_ssa)
memset(&value->ssa, 0, sizeof(value->ssa));
value->is_ssa = true;
/* Only overwrite the written components */
for (unsigned i = 0; i < NIR_MAX_VEC_COMPONENTS; i++) {
if (write_mask & (1 << i)) {
value->ssa.def[base_index + i] = from->ssa.def[i];
value->ssa.component[base_index + i] = from->ssa.component[i];
}
}
} else {
/* Non-ssa stores always write everything */
value->is_ssa = false;
value->deref = from->deref;
}
}
/* Try to load a single element of a vector from the copy_entry. If the data
* isn't available, just let the original intrinsic do the work.
*/
static bool
load_element_from_ssa_entry_value(struct copy_prop_var_state *state,
struct copy_entry *entry,
nir_builder *b, nir_intrinsic_instr *intrin,
struct value *value, unsigned index)
{
const struct glsl_type *type = entry->dst->type;
unsigned num_components = glsl_get_vector_elements(type);
assert(index < num_components);
/* We don't have the element available, so let the instruction do the work. */
if (!entry->src.ssa.def[index])
return false;
b->cursor = nir_instr_remove(&intrin->instr);
intrin->instr.block = NULL;
assert(entry->src.ssa.component[index] <
entry->src.ssa.def[index]->num_components);
nir_ssa_def *def = nir_channel(b, entry->src.ssa.def[index],
entry->src.ssa.component[index]);
*value = (struct value) {
.is_ssa = true,
{
.ssa = {
.def = { def },
.component = { 0 },
},
}
};
return true;
}
/* Do a "load" from an SSA-based entry return it in "value" as a value with a
* single SSA def. Because an entry could reference multiple different SSA
* defs, a vecN operation may be inserted to combine them into a single SSA
* def before handing it back to the caller. If the load instruction is no
* longer needed, it is removed and nir_instr::block is set to NULL. (It is
* possible, in some cases, for the load to be used in the vecN operation in
* which case it isn't deleted.)
*/
static bool
load_from_ssa_entry_value(struct copy_prop_var_state *state,
struct copy_entry *entry,
nir_builder *b, nir_intrinsic_instr *intrin,
nir_deref_instr *src, struct value *value)
{
if (is_array_deref_of_vector(src)) {
if (nir_src_is_const(src->arr.index)) {
return load_element_from_ssa_entry_value(state, entry, b, intrin, value,
nir_src_as_uint(src->arr.index));
}
/* An SSA copy_entry for the vector won't help indirect load. */
if (glsl_type_is_vector(entry->dst->type)) {
assert(entry->dst->type == nir_deref_instr_parent(src)->type);
/* TODO: If all SSA entries are there, try an if-ladder. */
return false;
}
}
*value = entry->src;
assert(value->is_ssa);
const struct glsl_type *type = entry->dst->type;
unsigned num_components = glsl_get_vector_elements(type);
nir_component_mask_t available = 0;
bool all_same = true;
for (unsigned i = 0; i < num_components; i++) {
if (value->ssa.def[i])
available |= (1 << i);
if (value->ssa.def[i] != value->ssa.def[0])
all_same = false;
if (value->ssa.component[i] != i)
all_same = false;
}
if (all_same) {
/* Our work here is done */
b->cursor = nir_instr_remove(&intrin->instr);
intrin->instr.block = NULL;
return true;
}
if (available != (1 << num_components) - 1 &&
intrin->intrinsic == nir_intrinsic_load_deref &&
(available & nir_ssa_def_components_read(&intrin->dest.ssa)) == 0) {
/* If none of the components read are available as SSA values, then we
* should just bail. Otherwise, we would end up replacing the uses of
* the load_deref a vecN() that just gathers up its components.
*/
return false;
}
b->cursor = nir_after_instr(&intrin->instr);
nir_ssa_def *load_def =
intrin->intrinsic == nir_intrinsic_load_deref ? &intrin->dest.ssa : NULL;
bool keep_intrin = false;
nir_ssa_def *comps[NIR_MAX_VEC_COMPONENTS];
for (unsigned i = 0; i < num_components; i++) {
if (value->ssa.def[i]) {
comps[i] = nir_channel(b, value->ssa.def[i], value->ssa.component[i]);
} else {
/* We don't have anything for this component in our
* list. Just re-use a channel from the load.
*/
if (load_def == NULL)
load_def = nir_load_deref(b, entry->dst);
if (load_def->parent_instr == &intrin->instr)
keep_intrin = true;
comps[i] = nir_channel(b, load_def, i);
}
}
nir_ssa_def *vec = nir_vec(b, comps, num_components);
value_set_ssa_components(value, vec, num_components);
if (!keep_intrin) {
/* Removing this instruction should not touch the cursor because we
* created the cursor after the intrinsic and have added at least one
* instruction (the vec) since then.
*/
assert(b->cursor.instr != &intrin->instr);
nir_instr_remove(&intrin->instr);
intrin->instr.block = NULL;
}
return true;
}
/**
* Specialize the wildcards in a deref chain
*
* This function returns a deref chain identical to \param deref except that
* some of its wildcards are replaced with indices from \param specific. The
* process is guided by \param guide which references the same type as \param
* specific but has the same wildcard array lengths as \param deref.
*/
static nir_deref_instr *
specialize_wildcards(nir_builder *b,
nir_deref_path *deref,
nir_deref_path *guide,
nir_deref_path *specific)
{
nir_deref_instr **deref_p = &deref->path[1];
nir_deref_instr **guide_p = &guide->path[1];
nir_deref_instr **spec_p = &specific->path[1];
nir_deref_instr *ret_tail = deref->path[0];
for (; *deref_p; deref_p++) {
if ((*deref_p)->deref_type == nir_deref_type_array_wildcard) {
/* This is where things get tricky. We have to search through
* the entry deref to find its corresponding wildcard and fill
* this slot in with the value from the src.
*/
while (*guide_p &&
(*guide_p)->deref_type != nir_deref_type_array_wildcard) {
guide_p++;
spec_p++;
}
assert(*guide_p && *spec_p);
ret_tail = nir_build_deref_follower(b, ret_tail, *spec_p);
guide_p++;
spec_p++;
} else {
ret_tail = nir_build_deref_follower(b, ret_tail, *deref_p);
}
}
return ret_tail;
}
/* Do a "load" from an deref-based entry return it in "value" as a value. The
* deref returned in "value" will always be a fresh copy so the caller can
* steal it and assign it to the instruction directly without copying it
* again.
*/
static bool
load_from_deref_entry_value(struct copy_prop_var_state *state,
struct copy_entry *entry,
nir_builder *b, nir_intrinsic_instr *intrin,
nir_deref_instr *src, struct value *value)
{
*value = entry->src;
b->cursor = nir_instr_remove(&intrin->instr);
nir_deref_path entry_dst_path, src_path;
nir_deref_path_init(&entry_dst_path, entry->dst, state->mem_ctx);
nir_deref_path_init(&src_path, src, state->mem_ctx);
bool need_to_specialize_wildcards = false;
nir_deref_instr **entry_p = &entry_dst_path.path[1];
nir_deref_instr **src_p = &src_path.path[1];
while (*entry_p && *src_p) {
nir_deref_instr *entry_tail = *entry_p++;
nir_deref_instr *src_tail = *src_p++;
if (src_tail->deref_type == nir_deref_type_array &&
entry_tail->deref_type == nir_deref_type_array_wildcard)
need_to_specialize_wildcards = true;
}
/* If the entry deref is longer than the source deref then it refers to a
* smaller type and we can't source from it.
*/
assert(*entry_p == NULL);
if (need_to_specialize_wildcards) {
/* The entry has some wildcards that are not in src. This means we need
* to construct a new deref based on the entry but using the wildcards
* from the source and guided by the entry dst. Oof.
*/
nir_deref_path entry_src_path;
nir_deref_path_init(&entry_src_path, entry->src.deref, state->mem_ctx);
value->deref = specialize_wildcards(b, &entry_src_path,
&entry_dst_path, &src_path);
nir_deref_path_finish(&entry_src_path);
}
/* If our source deref is longer than the entry deref, that's ok because
* it just means the entry deref needs to be extended a bit.
*/
while (*src_p) {
nir_deref_instr *src_tail = *src_p++;
value->deref = nir_build_deref_follower(b, value->deref, src_tail);
}
nir_deref_path_finish(&entry_dst_path);
nir_deref_path_finish(&src_path);
return true;
}
static bool
try_load_from_entry(struct copy_prop_var_state *state, struct copy_entry *entry,
nir_builder *b, nir_intrinsic_instr *intrin,
nir_deref_instr *src, struct value *value)
{
if (entry == NULL)
return false;
if (entry->src.is_ssa) {
return load_from_ssa_entry_value(state, entry, b, intrin, src, value);
} else {
return load_from_deref_entry_value(state, entry, b, intrin, src, value);
}
}
static void
invalidate_copies_for_cf_node(struct copy_prop_var_state *state,
struct util_dynarray *copies,
nir_cf_node *cf_node)
{
struct hash_entry *ht_entry = _mesa_hash_table_search(state->vars_written_map, cf_node);
assert(ht_entry);
struct vars_written *written = ht_entry->data;
if (written->modes) {
util_dynarray_foreach_reverse(copies, struct copy_entry, entry) {
if (entry->dst->mode & written->modes)
copy_entry_remove(copies, entry);
}
}
hash_table_foreach (written->derefs, entry) {
nir_deref_instr *deref_written = (nir_deref_instr *)entry->key;
kill_aliases(copies, deref_written, (uintptr_t)entry->data);
}
}
static void
print_value(struct value *value, unsigned num_components)
{
if (!value->is_ssa) {
printf(" %s ", glsl_get_type_name(value->deref->type));
nir_print_deref(value->deref, stdout);
return;
}
bool same_ssa = true;
for (unsigned i = 0; i < num_components; i++) {
if (value->ssa.component[i] != i ||
(i > 0 && value->ssa.def[i - 1] != value->ssa.def[i])) {
same_ssa = false;
break;
}
}
if (same_ssa) {
printf(" ssa_%d", value->ssa.def[0]->index);
} else {
for (int i = 0; i < num_components; i++) {
if (value->ssa.def[i])
printf(" ssa_%d[%u]", value->ssa.def[i]->index, value->ssa.component[i]);
else
printf(" _");
}
}
}
static void
print_copy_entry(struct copy_entry *entry)
{
printf(" %s ", glsl_get_type_name(entry->dst->type));
nir_print_deref(entry->dst, stdout);
printf(":\t");
unsigned num_components = glsl_get_vector_elements(entry->dst->type);
print_value(&entry->src, num_components);
printf("\n");
}
static void
dump_instr(nir_instr *instr)
{
printf(" ");
nir_print_instr(instr, stdout);
printf("\n");
}
static void
dump_copy_entries(struct util_dynarray *copies)
{
util_dynarray_foreach(copies, struct copy_entry, iter)
print_copy_entry(iter);
printf("\n");
}
static void
copy_prop_vars_block(struct copy_prop_var_state *state,
nir_builder *b, nir_block *block,
struct util_dynarray *copies)
{
if (debug) {
printf("# block%d\n", block->index);
dump_copy_entries(copies);
}
nir_foreach_instr_safe(instr, block) {
if (debug && instr->type == nir_instr_type_deref)
dump_instr(instr);
if (instr->type == nir_instr_type_call) {
if (debug) dump_instr(instr);
apply_barrier_for_modes(copies, nir_var_shader_out |
nir_var_shader_temp |
nir_var_function_temp |
nir_var_mem_ssbo |
nir_var_mem_shared);
if (debug) dump_copy_entries(copies);
continue;
}
if (instr->type != nir_instr_type_intrinsic)
continue;
nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
switch (intrin->intrinsic) {
case nir_intrinsic_barrier:
case nir_intrinsic_memory_barrier:
if (debug) dump_instr(instr);
apply_barrier_for_modes(copies, nir_var_shader_out |
nir_var_mem_ssbo |
nir_var_mem_shared);
break;
case nir_intrinsic_emit_vertex:
case nir_intrinsic_emit_vertex_with_counter:
if (debug) dump_instr(instr);
apply_barrier_for_modes(copies, nir_var_shader_out);
break;
case nir_intrinsic_load_deref: {
if (debug) dump_instr(instr);
nir_deref_instr *src = nir_src_as_deref(intrin->src[0]);
/* Direct array_derefs of vectors operate on the vectors (the parent
* deref). Indirects will be handled like other derefs.
*/
int vec_index = 0;
nir_deref_instr *vec_src = src;
if (is_array_deref_of_vector(src) && nir_src_is_const(src->arr.index)) {
vec_src = nir_deref_instr_parent(src);
unsigned vec_comps = glsl_get_vector_elements(vec_src->type);
vec_index = nir_src_as_uint(src->arr.index);
/* Loading from an invalid index yields an undef */
if (vec_index >= vec_comps) {
b->cursor = nir_instr_remove(instr);
nir_ssa_def *u = nir_ssa_undef(b, 1, intrin->dest.ssa.bit_size);
nir_ssa_def_rewrite_uses(&intrin->dest.ssa, nir_src_for_ssa(u));
break;
}
}
struct copy_entry *src_entry =
lookup_entry_for_deref(copies, src, nir_derefs_a_contains_b_bit);
struct value value = {0};
if (try_load_from_entry(state, src_entry, b, intrin, src, &value)) {
if (value.is_ssa) {
/* lookup_load has already ensured that we get a single SSA
* value that has all of the channels. We just have to do the
* rewrite operation. Note for array derefs of vectors, the
* channel 0 is used.
*/
if (intrin->instr.block) {
/* The lookup left our instruction in-place. This means it
* must have used it to vec up a bunch of different sources.
* We need to be careful when rewriting uses so we don't
* rewrite the vecN itself.
*/
nir_ssa_def_rewrite_uses_after(&intrin->dest.ssa,
nir_src_for_ssa(value.ssa.def[0]),
value.ssa.def[0]->parent_instr);
} else {
nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
nir_src_for_ssa(value.ssa.def[0]));
}
} else {
/* We're turning it into a load of a different variable */
intrin->src[0] = nir_src_for_ssa(&value.deref->dest.ssa);
/* Put it back in again. */
nir_builder_instr_insert(b, instr);
value_set_ssa_components(&value, &intrin->dest.ssa,
intrin->num_components);
}
state->progress = true;
} else {
value_set_ssa_components(&value, &intrin->dest.ssa,
intrin->num_components);
}
/* Now that we have a value, we're going to store it back so that we
* have the right value next time we come looking for it. In order
* to do this, we need an exact match, not just something that
* contains what we're looking for.
*/
struct copy_entry *entry =
lookup_entry_for_deref(copies, vec_src, nir_derefs_equal_bit);
if (!entry)
entry = copy_entry_create(copies, vec_src);
/* Update the entry with the value of the load. This way
* we can potentially remove subsequent loads.
*/
value_set_from_value(&entry->src, &value, vec_index,
(1 << intrin->num_components) - 1);
break;
}
case nir_intrinsic_store_deref: {
if (debug) dump_instr(instr);
nir_deref_instr *dst = nir_src_as_deref(intrin->src[0]);
assert(glsl_type_is_vector_or_scalar(dst->type));
/* Direct array_derefs of vectors operate on the vectors (the parent
* deref). Indirects will be handled like other derefs.
*/
int vec_index = 0;
nir_deref_instr *vec_dst = dst;
if (is_array_deref_of_vector(dst) && nir_src_is_const(dst->arr.index)) {
vec_dst = nir_deref_instr_parent(dst);
unsigned vec_comps = glsl_get_vector_elements(vec_dst->type);
vec_index = nir_src_as_uint(dst->arr.index);
/* Storing to an invalid index is a no-op. */
if (vec_index >= vec_comps) {
nir_instr_remove(instr);
break;
}
}
struct copy_entry *entry =
lookup_entry_for_deref(copies, dst, nir_derefs_equal_bit);
if (entry && value_equals_store_src(&entry->src, intrin)) {
/* If we are storing the value from a load of the same var the
* store is redundant so remove it.
*/
nir_instr_remove(instr);
} else {
struct value value = {0};
value_set_ssa_components(&value, intrin->src[1].ssa,
intrin->num_components);
unsigned wrmask = nir_intrinsic_write_mask(intrin);
struct copy_entry *entry =
get_entry_and_kill_aliases(copies, vec_dst, wrmask);
value_set_from_value(&entry->src, &value, vec_index, wrmask);
}
break;
}
case nir_intrinsic_copy_deref: {
if (debug) dump_instr(instr);
nir_deref_instr *dst = nir_src_as_deref(intrin->src[0]);
nir_deref_instr *src = nir_src_as_deref(intrin->src[1]);
if (nir_compare_derefs(src, dst) & nir_derefs_equal_bit) {
/* This is a no-op self-copy. Get rid of it */
nir_instr_remove(instr);
continue;
}
/* The copy_deref intrinsic doesn't keep track of num_components, so
* get it ourselves.
*/
unsigned num_components = glsl_get_vector_elements(dst->type);
unsigned full_mask = (1 << num_components) - 1;
/* Copy of direct array derefs of vectors are not handled. Just
* invalidate what's written and bail.
*/
if ((is_array_deref_of_vector(src) && nir_src_is_const(src->arr.index)) ||
(is_array_deref_of_vector(dst) && nir_src_is_const(dst->arr.index))) {
kill_aliases(copies, dst, full_mask);
break;
}
struct copy_entry *src_entry =
lookup_entry_for_deref(copies, src, nir_derefs_a_contains_b_bit);
struct value value;
if (try_load_from_entry(state, src_entry, b, intrin, src, &value)) {
/* If load works, intrin (the copy_deref) is removed. */
if (value.is_ssa) {
nir_store_deref(b, dst, value.ssa.def[0], full_mask);
} else {
/* If this would be a no-op self-copy, don't bother. */
if (nir_compare_derefs(value.deref, dst) & nir_derefs_equal_bit)
continue;
/* Just turn it into a copy of a different deref */
intrin->src[1] = nir_src_for_ssa(&value.deref->dest.ssa);
/* Put it back in again. */
nir_builder_instr_insert(b, instr);
}
state->progress = true;
} else {
value = (struct value) {
.is_ssa = false,
{ .deref = src },
};
}
struct copy_entry *dst_entry =
get_entry_and_kill_aliases(copies, dst, full_mask);
value_set_from_value(&dst_entry->src, &value, 0, full_mask);
break;
}
case nir_intrinsic_deref_atomic_add:
case nir_intrinsic_deref_atomic_imin:
case nir_intrinsic_deref_atomic_umin:
case nir_intrinsic_deref_atomic_imax:
case nir_intrinsic_deref_atomic_umax:
case nir_intrinsic_deref_atomic_and:
case nir_intrinsic_deref_atomic_or:
case nir_intrinsic_deref_atomic_xor:
case nir_intrinsic_deref_atomic_exchange:
case nir_intrinsic_deref_atomic_comp_swap:
if (debug) dump_instr(instr);
nir_deref_instr *dst = nir_src_as_deref(intrin->src[0]);
unsigned num_components = glsl_get_vector_elements(dst->type);
unsigned full_mask = (1 << num_components) - 1;
kill_aliases(copies, dst, full_mask);
break;
default:
continue; /* To skip the debug below. */
}
if (debug) dump_copy_entries(copies);
}
}
static void
copy_prop_vars_cf_node(struct copy_prop_var_state *state,
struct util_dynarray *copies,
nir_cf_node *cf_node)
{
switch (cf_node->type) {
case nir_cf_node_function: {
nir_function_impl *impl = nir_cf_node_as_function(cf_node);
struct util_dynarray impl_copies;
util_dynarray_init(&impl_copies, state->mem_ctx);
foreach_list_typed_safe(nir_cf_node, cf_node, node, &impl->body)
copy_prop_vars_cf_node(state, &impl_copies, cf_node);
break;
}
case nir_cf_node_block: {
nir_block *block = nir_cf_node_as_block(cf_node);
nir_builder b;
nir_builder_init(&b, state->impl);
copy_prop_vars_block(state, &b, block, copies);
break;
}
case nir_cf_node_if: {
nir_if *if_stmt = nir_cf_node_as_if(cf_node);
/* Clone the copies for each branch of the if statement. The idea is
* that they both see the same state of available copies, but do not
* interfere to each other.
*/
struct util_dynarray then_copies;
util_dynarray_clone(&then_copies, state->mem_ctx, copies);
struct util_dynarray else_copies;
util_dynarray_clone(&else_copies, state->mem_ctx, copies);
foreach_list_typed_safe(nir_cf_node, cf_node, node, &if_stmt->then_list)
copy_prop_vars_cf_node(state, &then_copies, cf_node);
foreach_list_typed_safe(nir_cf_node, cf_node, node, &if_stmt->else_list)
copy_prop_vars_cf_node(state, &else_copies, cf_node);
/* Both branches copies can be ignored, since the effect of running both
* branches was captured in the first pass that collects vars_written.
*/
invalidate_copies_for_cf_node(state, copies, cf_node);
break;
}
case nir_cf_node_loop: {
nir_loop *loop = nir_cf_node_as_loop(cf_node);
/* Invalidate before cloning the copies for the loop, since the loop
* body can be executed more than once.
*/
invalidate_copies_for_cf_node(state, copies, cf_node);
struct util_dynarray loop_copies;
util_dynarray_clone(&loop_copies, state->mem_ctx, copies);
foreach_list_typed_safe(nir_cf_node, cf_node, node, &loop->body)
copy_prop_vars_cf_node(state, &loop_copies, cf_node);
break;
}
default:
unreachable("Invalid CF node type");
}
}
static bool
nir_copy_prop_vars_impl(nir_function_impl *impl)
{
void *mem_ctx = ralloc_context(NULL);
if (debug) {
nir_metadata_require(impl, nir_metadata_block_index);
printf("## nir_copy_prop_vars_impl for %s\n", impl->function->name);
}
struct copy_prop_var_state state = {
.impl = impl,
.mem_ctx = mem_ctx,
.lin_ctx = linear_zalloc_parent(mem_ctx, 0),
.vars_written_map = _mesa_pointer_hash_table_create(mem_ctx),
};
gather_vars_written(&state, NULL, &impl->cf_node);
copy_prop_vars_cf_node(&state, NULL, &impl->cf_node);
if (state.progress) {
nir_metadata_preserve(impl, nir_metadata_block_index |
nir_metadata_dominance);
} else {
#ifndef NDEBUG
impl->valid_metadata &= ~nir_metadata_not_properly_reset;
#endif
}
ralloc_free(mem_ctx);
return state.progress;
}
bool
nir_opt_copy_prop_vars(nir_shader *shader)
{
bool progress = false;
nir_foreach_function(function, shader) {
if (!function->impl)
continue;
progress |= nir_copy_prop_vars_impl(function->impl);
}
return progress;
}
|