-
Notifications
You must be signed in to change notification settings - Fork 24
/
Copy pathir_sccp.c
2699 lines (2448 loc) · 76.8 KB
/
ir_sccp.c
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
/*
* IR - Lightweight JIT Compilation Framework
* (SCCP - Sparse Conditional Constant Propagation)
* Copyright (C) 2022 Zend by Perforce.
* Authors: Dmitry Stogov <dmitry@php.net>
*
* The SCCP algorithm is based on M. N. Wegman and F. K. Zadeck publication
* See: M. N. Wegman and F. K. Zadeck. "Constant propagation with conditional branches"
* ACM Transactions on Programming Languages and Systems, 13(2):181-210, April 1991
*/
#include "ir.h"
#include "ir_private.h"
#define IR_COMBO_COPY_PROPAGATION 1
#define IR_TOP IR_UNUSED
#define IR_BOTTOM IR_LAST_OP
#define IR_MAKE_TOP(ref) do {IR_ASSERT(ref > 0); _values[ref].optx = IR_TOP;} while (0)
#define IR_MAKE_BOTTOM(ref) do {IR_ASSERT(ref > 0); _values[ref].optx = IR_BOTTOM;} while (0)
#define IR_IS_TOP(ref) (ref >= 0 && _values[ref].optx == IR_TOP)
#define IR_IS_BOTTOM(ref) (ref >= 0 && _values[ref].optx == IR_BOTTOM)
#define IR_IS_REACHABLE(ref) _ir_is_reachable_ctrl(ctx, _values, ref)
IR_ALWAYS_INLINE bool _ir_is_reachable_ctrl(ir_ctx *ctx, ir_insn *_values, ir_ref ref)
{
IR_ASSERT(!IR_IS_CONST_REF(ref));
IR_ASSERT(ir_op_flags[ctx->ir_base[ref].op] & IR_OP_FLAG_CONTROL);
return _values[ref].optx != IR_TOP; /* BOTTOM, IF or MERGE */
}
#if IR_COMBO_COPY_PROPAGATION
IR_ALWAYS_INLINE ir_ref ir_sccp_identity(ir_insn *_values, ir_ref a)
{
if (a > 0 && _values[a].op == IR_COPY) {
a = _values[a].op1;
IR_ASSERT(a < 0 || _values[a].op != IR_COPY); /* this may be a copy of symbolic constant */
}
return a;
}
static void ir_sccp_add_identity(ir_insn *_values, ir_ref src, ir_ref dst, ir_type type)
{
_values[dst].optx = IR_OPT(IR_COPY, type);
_values[dst].op1 = src;
}
#endif
static ir_ref ir_sccp_fold(ir_ctx *ctx, ir_insn *_values, ir_ref res, uint32_t opt, ir_ref op1, ir_ref op2, ir_ref op3)
{
ir_insn *op1_insn, *op2_insn, *op3_insn, *insn;
#if IR_COMBO_COPY_PROPAGATION
op1 = ir_sccp_identity(_values, op1);
op2 = ir_sccp_identity(_values, op2);
op3 = ir_sccp_identity(_values, op3);
#endif
restart:
op1_insn = (op1 > 0 && IR_IS_CONST_OP(_values[op1].op)) ? _values + op1 : ctx->ir_base + op1;
op2_insn = (op2 > 0 && IR_IS_CONST_OP(_values[op2].op)) ? _values + op2 : ctx->ir_base + op2;
op3_insn = (op3 > 0 && IR_IS_CONST_OP(_values[op3].op)) ? _values + op3 : ctx->ir_base + op3;
switch (ir_folding(ctx, opt, op1, op2, op3, op1_insn, op2_insn, op3_insn)) {
case IR_FOLD_DO_RESTART:
opt = ctx->fold_insn.optx;
op1 = ctx->fold_insn.op1;
op2 = ctx->fold_insn.op2;
op3 = ctx->fold_insn.op3;
goto restart;
case IR_FOLD_DO_EMIT:
goto make_bottom;
case IR_FOLD_DO_COPY:
op1 = ctx->fold_insn.op1;
#if IR_COMBO_COPY_PROPAGATION
op1 = ir_sccp_identity(_values, op1);
#endif
insn = (op1 > 0 && IR_IS_CONST_OP(_values[op1].op)) ? _values + op1 : ctx->ir_base + op1;
if (IR_IS_CONST_OP(insn->op)) {
/* pass */
#if IR_COMBO_COPY_PROPAGATION
} else {
if (_values[res].optx == IR_TOP) {
/* pass to new copy */
} else if (_values[res].op == IR_COPY) {
if (_values[res].op1 == op1) {
return 0; /* not changed */
} else {
goto make_bottom;
}
} else {
IR_ASSERT(_values[res].optx != IR_BOTTOM);
/* we don't check for widening */
}
/* create new COPY */
ir_sccp_add_identity(_values, op1, res, insn->type);
return 1;
#else
goto make_bottom;
#endif
}
break;
case IR_FOLD_DO_CONST:
insn = &ctx->fold_insn;
break;
default:
IR_ASSERT(0);
return 0;
}
if (IR_IS_TOP(res)) {
_values[res].optx = IR_OPT(insn->type, insn->type);
_values[res].val.u64 = insn->val.u64;
return 1;
} else if (_values[res].opt == IR_OPT(insn->type, insn->type) && _values[res].val.u64 == insn->val.u64) {
return 0; /* not changed */
}
make_bottom:
IR_MAKE_BOTTOM(res);
return 1;
}
static bool ir_sccp_meet_phi(ir_ctx *ctx, ir_insn *_values, ir_ref i, ir_insn *insn, ir_bitqueue *worklist)
{
ir_ref j, n, input, *merge_input, *p;
ir_insn *v, *new_const = NULL;
#if IR_COMBO_COPY_PROPAGATION
ir_ref new_copy = IR_UNUSED;
#endif
if (!IR_IS_REACHABLE(insn->op1)) {
return 0;
}
n = insn->inputs_count;
if (n > 3 && _values[i].optx == IR_TOP) {
for (j = 0; j < (n>>2); j++) {
_values[i+j+1].optx = IR_BOTTOM; /* keep the tail of a long multislot instruction */
}
}
p = insn->ops + 2;
merge_input = ctx->ir_base[insn->op1].ops + 1;
for (; --n > 0; p++, merge_input++) {
IR_ASSERT(*merge_input > 0);
if (!IR_IS_REACHABLE(*merge_input)) {
continue;
}
input = *p;
if (IR_IS_CONST_REF(input)) {
v = &ctx->ir_base[input];
} else if (input == i) {
continue;
} else {
v = &_values[input];
if (v->op == IR_TOP) {
/* do backward propagaton only once */
if (!v->op1) {
v->op1 = 1;
ir_bitqueue_add(worklist, input);
}
continue;
#if IR_COMBO_COPY_PROPAGATION
} else if (v->op == IR_COPY) {
input = v->op1;
IR_ASSERT(input < 0 || _values[input].op != IR_COPY);
new_copy = input;
goto next;
} else if (v->op == IR_BOTTOM) {
new_copy = input;
goto next;
#else
} else if (v->op == IR_BOTTOM) {
goto make_bottom;
#endif
}
}
new_const = v;
goto next;
}
IR_ASSERT(_values[i].optx == IR_TOP);
return 0;
next:
p++;
merge_input++;
/* for all live merge inputs */
for (; --n > 0; p++, merge_input++) {
IR_ASSERT(*merge_input > 0);
if (!IR_IS_REACHABLE(*merge_input)) {
continue;
}
input = *p;
if (IR_IS_CONST_REF(input)) {
v = &ctx->ir_base[input];
} else if (input == i) {
continue;
} else {
v = &_values[input];
if (v->op == IR_TOP) {
/* do backward propagaton only once */
if (!v->op1) {
v->op1 = 1;
ir_bitqueue_add(worklist, input);
}
continue;
#if IR_COMBO_COPY_PROPAGATION
} else if (v->op == IR_COPY) {
input = v->op1;
IR_ASSERT(input < 0 || _values[input].op != IR_COPY);
if (new_copy == input) {
continue;
}
goto make_bottom;
#endif
} else if (v->op == IR_BOTTOM) {
#if IR_COMBO_COPY_PROPAGATION
if (new_copy == input) {
continue;
}
#endif
goto make_bottom;
}
}
if (!new_const || new_const->opt != v->opt || new_const->val.u64 != v->val.u64) {
goto make_bottom;
}
}
#if IR_COMBO_COPY_PROPAGATION
if (new_copy) {
if (_values[i].op == IR_COPY) {
if (_values[i].op1 == new_copy) {
return 0; /* not changed */
} else {
goto make_bottom;
}
} else {
IR_ASSERT(_values[i].optx != IR_BOTTOM);
/* we don't check for widening */
ir_sccp_add_identity(_values, new_copy, i, insn->type);
return 1;
}
}
#endif
if (_values[i].optx == IR_TOP) {
_values[i].optx = new_const->opt;
_values[i].val.u64 = new_const->val.u64;
return 1;
} else if (_values[i].opt == new_const->opt && _values[i].val.u64 == new_const->val.u64) {
return 0;
}
make_bottom:
IR_MAKE_BOTTOM(i);
return 1;
}
static bool ir_is_dead_load_ex(ir_ctx *ctx, ir_ref ref, uint32_t flags, ir_insn *insn)
{
if ((flags & (IR_OP_FLAG_MEM|IR_OP_FLAG_MEM_MASK)) == (IR_OP_FLAG_MEM|IR_OP_FLAG_MEM_LOAD)) {
return ctx->use_lists[ref].count == 1;
} else if (insn->op == IR_ALLOCA || insn->op == IR_BLOCK_BEGIN) {
return ctx->use_lists[ref].count == 1;
}
return 0;
}
static bool ir_is_dead_load(ir_ctx *ctx, ir_ref ref)
{
if (ctx->use_lists[ref].count == 1) {
uint32_t flags = ir_op_flags[ctx->ir_base[ref].op];
if ((flags & (IR_OP_FLAG_MEM|IR_OP_FLAG_MEM_MASK)) == (IR_OP_FLAG_MEM|IR_OP_FLAG_MEM_LOAD)) {
return 1;
} else if (ctx->ir_base[ref].op == IR_ALLOCA) {
return 1;
}
}
return 0;
}
static bool ir_is_dead(ir_ctx *ctx, ir_ref ref)
{
if (ctx->use_lists[ref].count == 0) {
return IR_IS_FOLDABLE_OP(ctx->ir_base[ref].op);
} else {
return ir_is_dead_load(ctx, ref);
}
return 0;
}
static bool ir_sccp_is_true(ir_ctx *ctx, ir_insn *_values, ir_ref a)
{
ir_insn *v = IR_IS_CONST_REF(a) ? &ctx->ir_base[a] : &_values[a];
return ir_const_is_true(v);
}
static bool ir_sccp_is_equal(ir_ctx *ctx, ir_insn *_values, ir_ref a, ir_ref b)
{
ir_insn *v1 = IR_IS_CONST_REF(a) ? &ctx->ir_base[a] : &_values[a];
ir_insn *v2 = IR_IS_CONST_REF(b) ? &ctx->ir_base[b] : &_values[b];
IR_ASSERT(!IR_IS_SYM_CONST(v1->op));
IR_ASSERT(!IR_IS_SYM_CONST(v2->op));
return v1->val.u64 == v2->val.u64;
}
static void ir_sccp_analyze(ir_ctx *ctx, ir_insn *_values, ir_bitqueue *worklist, ir_bitqueue *iter_worklist)
{
ir_ref i, j, n, *p, use;
ir_use_list *use_list;
ir_insn *insn, *use_insn;
uint32_t flags;
/* A bit modified SCCP algorithm of M. N. Wegman and F. K. Zadeck */
worklist->pos = 0;
ir_bitset_incl(worklist->set, 1);
while ((i = ir_bitqueue_pop(worklist)) >= 0) {
insn = &ctx->ir_base[i];
flags = ir_op_flags[insn->op];
if (flags & IR_OP_FLAG_DATA) {
if (ctx->use_lists[i].count == 0) {
/* dead code */
continue;
} else if (insn->op == IR_PHI) {
if (!ir_sccp_meet_phi(ctx, _values, i, insn, worklist)) {
continue;
}
} else if (EXPECTED(IR_IS_FOLDABLE_OP(insn->op))) {
bool may_benefit = 0;
bool has_top = 0;
IR_ASSERT(!IR_OP_HAS_VAR_INPUTS(flags));
n = IR_INPUT_EDGES_COUNT(flags);
for (p = insn->ops + 1; n > 0; p++, n--) {
ir_ref input = *p;
if (input > 0) {
if (_values[input].optx == IR_TOP) {
has_top = 1;
/* do backward propagaton only once */
if (!_values[input].op1) {
_values[input].op1 = 1;
ir_bitqueue_add(worklist, input);
}
} else if (_values[input].optx != IR_BOTTOM) {
/* Perform folding only if some of direct inputs
* is going to be replaced by a constant or copy.
* This approach may miss some folding optimizations
* dependent on indirect inputs. e.g. reassociation.
*/
may_benefit = 1;
}
}
}
if (has_top) {
continue;
}
if (!may_benefit) {
IR_MAKE_BOTTOM(i);
if (insn->op == IR_FP2FP || insn->op == IR_FP2INT || insn->op == IR_TRUNC
|| insn->op == IR_ZEXT || insn->op == IR_SEXT || insn->op == IR_EQ || insn->op == IR_NE) {
ir_bitqueue_add(iter_worklist, i);
}
} else if (!ir_sccp_fold(ctx, _values, i, insn->opt, insn->op1, insn->op2, insn->op3)) {
/* not changed */
continue;
} else if (_values[i].optx == IR_BOTTOM) {
insn = &ctx->ir_base[i];
if (insn->op == IR_FP2FP || insn->op == IR_FP2INT || insn->op == IR_TRUNC
|| insn->op == IR_ZEXT || insn->op == IR_SEXT || insn->op == IR_EQ || insn->op == IR_NE) {
ir_bitqueue_add(iter_worklist, i);
}
}
} else {
IR_MAKE_BOTTOM(i);
}
} else if (flags & IR_OP_FLAG_BB_START) {
if (insn->op == IR_MERGE || insn->op == IR_BEGIN) {
ir_bitqueue_add(iter_worklist, i);
}
if (insn->op == IR_MERGE || insn->op == IR_LOOP_BEGIN) {
ir_ref unfeasible_inputs = 0;
n = insn->inputs_count;
if (n > 3 && _values[i].optx == IR_TOP) {
for (j = 0; j < (n>>2); j++) {
_values[i+j+1].optx = IR_BOTTOM; /* keep the tail of a long multislot instruction */
}
}
for (p = insn->ops + 1; n > 0; p++, n--) {
ir_ref input = *p;
IR_ASSERT(input > 0);
if (!IR_IS_REACHABLE(input)) {
unfeasible_inputs++;
}
}
if (unfeasible_inputs == 0) {
IR_MAKE_BOTTOM(i);
} else if (_values[i].optx != IR_MERGE || _values[i].op1 != unfeasible_inputs) {
_values[i].optx = IR_MERGE;
_values[i].op1 = unfeasible_inputs;
} else {
continue;
}
} else {
IR_ASSERT(insn->op == IR_START || IR_IS_REACHABLE(insn->op1));
IR_MAKE_BOTTOM(i);
}
} else {
IR_ASSERT(insn->op1 > 0);
if (!IR_IS_REACHABLE(insn->op1)) {
/* control inpt is not feasible */
continue;
}
if (insn->op == IR_IF) {
if (IR_IS_TOP(insn->op2)) {
/* do backward propagaton only once */
if (!_values[insn->op2].op1) {
_values[insn->op2].op1 = 1;
ir_bitqueue_add(worklist, insn->op2);
}
continue;
}
if (!IR_IS_BOTTOM(insn->op2)
#if IR_COMBO_COPY_PROPAGATION
&& (IR_IS_CONST_REF(insn->op2) || _values[insn->op2].op != IR_COPY)
#endif
) {
bool b = ir_sccp_is_true(ctx, _values, insn->op2);
use_list = &ctx->use_lists[i];
IR_ASSERT(use_list->count == 2);
p = &ctx->use_edges[use_list->refs];
use = *p;
use_insn = &ctx->ir_base[use];
IR_ASSERT(use_insn->op == IR_IF_TRUE || use_insn->op == IR_IF_FALSE);
if ((use_insn->op == IR_IF_TRUE) != b) {
use = *(p+1);
IR_ASSERT(ctx->ir_base[use].op == IR_IF_TRUE || ctx->ir_base[use].op == IR_IF_FALSE);
}
if (_values[i].optx == IR_TOP) {
_values[i].optx = IR_IF;
_values[i].op1 = use;
ir_bitqueue_add(worklist, use);
continue;
} else if (_values[i].optx == IR_IF && _values[i].op1 == use) {
continue;
}
}
IR_MAKE_BOTTOM(i);
} else if (insn->op == IR_SWITCH) {
if (IR_IS_TOP(insn->op2)) {
/* do backward propagaton only once */
if (!_values[insn->op2].op1) {
_values[insn->op2].op1 = 1;
ir_bitqueue_add(worklist, insn->op2);
}
continue;
}
if (!IR_IS_BOTTOM(insn->op2)
#if IR_COMBO_COPY_PROPAGATION
&& (IR_IS_CONST_REF(insn->op2) || _values[insn->op2].op != IR_COPY)
#endif
) {
ir_ref use_case = IR_UNUSED;
use_list = &ctx->use_lists[i];
n = use_list->count;
for (j = 0, p = &ctx->use_edges[use_list->refs]; j < n; j++, p++) {
use = *p;
IR_ASSERT(use > 0);
use_insn = &ctx->ir_base[use];
if (use_insn->op == IR_CASE_VAL) {
if (ir_sccp_is_equal(ctx, _values, insn->op2, use_insn->op2)) {
use_case = use;
break;
}
} else if (use_insn->op == IR_CASE_DEFAULT) {
use_case = use;
}
}
if (use_case) {
use_insn = &ctx->ir_base[use_case];
if (_values[i].optx == IR_TOP) {
_values[i].optx = IR_IF;
_values[i].op1 = use_case;
ir_bitqueue_add(worklist, use_case);
continue;
} else if (_values[i].optx == IR_IF || _values[i].op1 == use_case) {
continue;
}
}
}
IR_MAKE_BOTTOM(i);
} else if (ir_is_dead_load_ex(ctx, i, flags, insn)) {
/* dead load */
_values[i].optx = IR_LOAD;
} else {
IR_MAKE_BOTTOM(i);
/* control, call, load and store instructions may have unprocessed inputs */
n = IR_INPUT_EDGES_COUNT(flags);
if (IR_OP_HAS_VAR_INPUTS(flags) && (n = insn->inputs_count) > 3) {
for (j = 0; j < (n>>2); j++) {
_values[i+j+1].optx = IR_BOTTOM; /* keep the tail of a long multislot instruction */
}
for (j = 2, p = insn->ops + j; j <= n; j++, p++) {
IR_ASSERT(IR_OPND_KIND(flags, j) == IR_OPND_DATA);
use = *p;
if (use > 0 && UNEXPECTED(_values[use].optx == IR_TOP)) {
ir_bitqueue_add(worklist, use);
}
}
} else if (n >= 2) {
IR_ASSERT(IR_OPND_KIND(flags, 2) == IR_OPND_DATA);
use = insn->op2;
if (use > 0 && UNEXPECTED(_values[use].optx == IR_TOP)) {
ir_bitqueue_add(worklist, use);
}
if (n > 2) {
IR_ASSERT(n == 3);
IR_ASSERT(IR_OPND_KIND(flags, 3) == IR_OPND_DATA);
use = insn->op3;
if (use > 0 && UNEXPECTED(_values[use].optx == IR_TOP)) {
ir_bitqueue_add(worklist, use);
}
}
}
}
}
use_list = &ctx->use_lists[i];
n = use_list->count;
for (p = &ctx->use_edges[use_list->refs]; n > 0; p++, n--) {
use = *p;
if (_values[use].optx != IR_BOTTOM) {
ir_bitqueue_add(worklist, use);
}
}
}
#ifdef IR_DEBUG
if (ctx->flags & IR_DEBUG_SCCP) {
for (i = 1; i < ctx->insns_count; i++) {
if (IR_IS_CONST_OP(_values[i].op) || IR_IS_SYM_CONST(_values[i].op)) {
fprintf(stderr, "%d. CONST(", i);
ir_print_const(ctx, &_values[i], stderr, true);
fprintf(stderr, ")\n");
#if IR_COMBO_COPY_PROPAGATION
} else if (_values[i].op == IR_COPY) {
fprintf(stderr, "%d. COPY(%d)\n", i, _values[i].op1);
#endif
} else if (IR_IS_TOP(i)) {
fprintf(stderr, "%d. TOP\n", i);
} else if (_values[i].op == IR_IF) {
fprintf(stderr, "%d. IF(%d)\n", i, _values[i].op1);
} else if (_values[i].op == IR_MERGE) {
fprintf(stderr, "%d. MERGE(%d)\n", i, _values[i].op1);
} else if (!IR_IS_BOTTOM(i)) {
fprintf(stderr, "%d. %d\n", i, _values[i].op);
}
}
}
#endif
}
/**********************/
/* SCCP trasformation */
/**********************/
static void ir_sccp_make_nop(ir_ctx *ctx, ir_ref ref)
{
ir_ref j, n, *p;
ir_insn *insn;
CLEAR_USES(ref);
insn = &ctx->ir_base[ref];
n = insn->inputs_count;
insn->opt = IR_NOP; /* keep "inputs_count" */
for (j = 1, p = insn->ops + j; j <= n; j++, p++) {
*p = IR_UNUSED;
}
}
static void ir_sccp_remove_insn(ir_ctx *ctx, ir_insn *_values, ir_ref ref, ir_bitqueue *worklist)
{
ir_ref j, n, *p;
ir_insn *insn;
CLEAR_USES(ref);
insn = &ctx->ir_base[ref];
n = insn->inputs_count;
insn->opt = IR_NOP; /* keep "inputs_count" */
for (j = 1, p = insn->ops + j; j <= n; j++, p++) {
ir_ref input = *p;
*p = IR_UNUSED;
/* we may skip nodes that are going to be removed by SCCP (TOP, CONST and COPY) */
if (input > 0 && _values[input].op > IR_COPY) {
ir_use_list_remove_all(ctx, input, ref);
if (ir_is_dead(ctx, input)) {
/* schedule DCE */
ir_bitqueue_add(worklist, input);
}
}
}
}
static void ir_sccp_replace_insn(ir_ctx *ctx, ir_insn *_values, ir_ref ref, ir_ref new_ref, ir_bitqueue *worklist)
{
ir_ref j, n, *p, use, i;
ir_insn *insn;
ir_use_list *use_list;
IR_ASSERT(ref != new_ref);
insn = &ctx->ir_base[ref];
n = insn->inputs_count;
insn->opt = IR_NOP; /* keep "inputs_count" */
for (j = 1, p = insn->ops + 1; j <= n; j++, p++) {
ir_ref input = *p;
*p = IR_UNUSED;
/* we may skip nodes that are going to be removed by SCCP (TOP, CONST and COPY) */
if (input > 0 && _values[input].op > IR_COPY) {
ir_use_list_remove_all(ctx, input, ref);
if (ir_is_dead(ctx, input)) {
/* schedule DCE */
ir_bitqueue_add(worklist, input);
}
}
}
use_list = &ctx->use_lists[ref];
n = use_list->count;
p = &ctx->use_edges[use_list->refs];
if (new_ref <= 0) {
/* constant or IR_UNUSED */
for (; n; p++, n--) {
use = *p;
/* we may skip nodes that are going to be removed by SCCP (TOP, CONST and COPY) */
if (_values[use].op > IR_COPY) {
insn = &ctx->ir_base[use];
i = ir_insn_find_op(insn, ref);
if (!i) continue;
IR_ASSERT(i > 0);
ir_insn_set_op(insn, i, new_ref);
/* schedule folding */
ir_bitqueue_add(worklist, use);
}
}
} else {
for (j = 0; j < n; j++, p++) {
use = *p;
/* we may skip nodes that are going to be removed by SCCP (TOP, CONST and COPY) */
if (_values[use].optx == IR_BOTTOM) {
insn = &ctx->ir_base[use];
i = ir_insn_find_op(insn, ref);
IR_ASSERT(i > 0);
ir_insn_set_op(insn, i, new_ref);
if (ir_use_list_add(ctx, new_ref, use)) {
/* restore after reallocation */
use_list = &ctx->use_lists[ref];
n = use_list->count;
p = &ctx->use_edges[use_list->refs + j];
}
/* schedule folding */
ir_bitqueue_add(worklist, use);
}
}
}
CLEAR_USES(ref);
}
static void ir_sccp_remove_if(ir_ctx *ctx, ir_insn *_values, ir_ref ref, ir_ref dst)
{
ir_ref next;
ir_insn *insn, *next_insn;
insn = &ctx->ir_base[ref];
if (ctx->use_lists[dst].count == 1) {
next = ctx->use_edges[ctx->use_lists[dst].refs];
next_insn = &ctx->ir_base[next];
/* remove IF and IF_TRUE/FALSE from double linked control list */
next_insn->op1 = insn->op1;
ir_use_list_replace_one(ctx, insn->op1, ref, next);
/* remove IF and IF_TRUE/FALSE instructions */
ir_sccp_make_nop(ctx, ref);
ir_sccp_make_nop(ctx, dst);
} else {
insn->op2 = IR_UNUSED;
insn->optx = IR_OPTX(IR_END, IR_VOID, 1);
next_insn = &ctx->ir_base[dst];
next_insn->op = IR_BEGIN;
}
}
static void ir_sccp_remove_unfeasible_merge_inputs(ir_ctx *ctx, ir_insn *_values, ir_ref ref, ir_ref unfeasible_inputs)
{
ir_ref i, j, n, k, *p, use;
ir_insn *insn, *use_insn;
ir_use_list *use_list;
ir_bitset life_inputs;
insn = &ctx->ir_base[ref];
IR_ASSERT(insn->op == IR_MERGE || insn->op == IR_LOOP_BEGIN);
n = insn->inputs_count;
if (n - unfeasible_inputs == 1) {
/* remove MERGE completely */
for (j = 1; j <= n; j++) {
ir_ref input = ir_insn_op(insn, j);
if (input && IR_IS_REACHABLE(input)) {
ir_insn *input_insn = &ctx->ir_base[input];
IR_ASSERT(input_insn->op == IR_END || input_insn->op == IR_LOOP_END||
input_insn->op == IR_IJMP || input_insn->op == IR_UNREACHABLE);
if (input_insn->op == IR_END || input_insn->op == IR_LOOP_END) {
ir_ref prev, next = IR_UNUSED;
ir_insn *next_insn = NULL;
prev = input_insn->op1;
use_list = &ctx->use_lists[ref];
if (use_list->count == 1) {
next = ctx->use_edges[use_list->refs];
next_insn = &ctx->ir_base[next];
} else {
k = 0;
p = &ctx->use_edges[use_list->refs];
while (k < use_list->count) {
use = *p;
use_insn = &ctx->ir_base[use];
#if IR_COMBO_COPY_PROPAGATION
IR_ASSERT((use_insn->op != IR_PHI) && "PHI must be already removed");
#else
if (use_insn->op == IR_PHI) {
/* Convert PHI into COPY */
ir_ref i, n = use_insn->inputs_count;
for (i = 2; i <= n; i++) {
if (i != j + 1) {
ir_ref from = ir_insn_op(use_insn, i);
if (from > 0) {
ir_use_list_remove_one(ctx, from, use);
}
ir_insn_set_op(use_insn, i, IR_UNUSED);
}
}
use_insn->optx = IR_OPTX(IR_COPY, use_insn->type, 1);
use_insn->op1 = ir_insn_op(use_insn, j + 1);
ir_insn_set_op(use_insn, j + 1, IR_UNUSED);
ir_use_list_remove_one(ctx, ref, use);
p = &ctx->use_edges[use_list->refs + k];
continue;
}
#endif
if (ir_op_flags[use_insn->op] & IR_OP_FLAG_CONTROL) {
IR_ASSERT(!next);
next = use;
next_insn = use_insn;
} else if (use_insn->op != IR_NOP) {
IR_ASSERT(use_insn->op1 == ref);
IR_ASSERT(use_insn->op == IR_VAR);
ir_ref region = prev;
while (!IR_IS_BB_START(ctx->ir_base[region].op)) {
region = ctx->ir_base[region].op1;
}
use_insn->op1 = region;
ir_use_list_add(ctx, region, use);
p = &ctx->use_edges[use_list->refs + k];
}
k++;
p++;
}
}
IR_ASSERT(prev && next);
if (prev < next) {
/* remove MERGE and input END from double linked control list */
next_insn->op1 = prev;
ir_use_list_replace_one(ctx, prev, input, next);
/* remove MERGE and input END instructions */
ir_sccp_make_nop(ctx, ref);
ir_sccp_make_nop(ctx, input);
} else {
for (i = 2; i <= n; i++) {
ir_insn_set_op(insn, i, IR_UNUSED);
}
insn->op = IR_BEGIN;
insn->op1 = input;
input_insn->op = IR_END;
}
break;
} else {
for (i = 2; i <= n; i++) {
ir_insn_set_op(insn, i, IR_UNUSED);
}
insn->op = IR_BEGIN;
insn->op1 = input;
}
}
}
} else {
n = insn->inputs_count;
i = 1;
life_inputs = ir_bitset_malloc(n + 1);
for (j = 1; j <= n; j++) {
ir_ref input = ir_insn_op(insn, j);
if (input) {
if (i != j) {
ir_insn_set_op(insn, i, input);
}
ir_bitset_incl(life_inputs, j);
i++;
}
}
j = i;
while (j <= n) {
ir_insn_set_op(insn, j, IR_UNUSED);
j++;
}
i--;
insn->inputs_count = i;
n++;
use_list = &ctx->use_lists[ref];
if (use_list->count > 1) {
for (k = 0, p = &ctx->use_edges[use_list->refs]; k < use_list->count; k++, p++) {
use = *p;
use_insn = &ctx->ir_base[use];
if (use_insn->op == IR_PHI) {
i = 2;
for (j = 2; j <= n; j++) {
ir_ref input = ir_insn_op(use_insn, j);
if (ir_bitset_in(life_inputs, j - 1)) {
IR_ASSERT(input);
if (i != j) {
ir_insn_set_op(use_insn, i, input);
}
i++;
} else if (!IR_IS_CONST_REF(input)) {
ir_use_list_remove_one(ctx, input, use);
}
}
while (i <= n) {
ir_insn_set_op(use_insn, i, IR_UNUSED);
i++;
}
use_insn->inputs_count = insn->inputs_count + 1;
}
}
}
ir_mem_free(life_inputs);
}
}
static void ir_sccp_transform(ir_ctx *ctx, ir_insn *_values, ir_bitqueue *worklist, ir_bitqueue *iter_worklist)
{
ir_ref i, j;
ir_insn *value;
for (i = 1, value = _values + i; i < ctx->insns_count; value++, i++) {
if (value->op == IR_BOTTOM) {
continue;
} else if (IR_IS_CONST_OP(value->op)) {
/* replace instruction by constant */
j = ir_const(ctx, value->val, value->type);
ir_sccp_replace_insn(ctx, _values, i, j, iter_worklist);
} else if (IR_IS_SYM_CONST(value->op)) {
/* replace instruction by constant */
j = ir_const_ex(ctx, value->val, value->type, value->optx);
ir_sccp_replace_insn(ctx, _values, i, j, iter_worklist);
#if IR_COMBO_COPY_PROPAGATION
} else if (value->op == IR_COPY) {
ir_sccp_replace_insn(ctx, _values, i, value->op1, iter_worklist);
#endif
} else if (value->op == IR_TOP) {
/* remove unreachable instruction */
ir_insn *insn = &ctx->ir_base[i];
if (insn->op == IR_NOP) {
/* already removed */
} else if (ir_op_flags[insn->op] & (IR_OP_FLAG_DATA|IR_OP_FLAG_MEM)) {
if (insn->op != IR_PARAM && (insn->op != IR_VAR || _values[insn->op1].op == IR_TOP)) {
ir_sccp_remove_insn(ctx, _values, i, iter_worklist);
}
} else {
if (ir_op_flags[insn->op] & IR_OP_FLAG_TERMINATOR) {
/* remove from terminators list */
ir_ref prev = ctx->ir_base[1].op1;
if (prev == i) {
ctx->ir_base[1].op1 = insn->op3;
} else {
while (prev) {
if (ctx->ir_base[prev].op3 == i) {
ctx->ir_base[prev].op3 = insn->op3;
break;
}
prev = ctx->ir_base[prev].op3;
}
}
}
ir_sccp_replace_insn(ctx, _values, i, IR_UNUSED, iter_worklist);
}
} else if (value->op == IR_IF) {
/* remove one way IF/SWITCH */
ir_sccp_remove_if(ctx, _values, i, value->op1);
} else if (value->op == IR_MERGE) {
/* schedule merge to remove unfeasible MERGE inputs */
ir_bitqueue_add(worklist, i);
} else if (value->op == IR_LOAD) {
/* schedule dead load elimination */
ir_bitqueue_add(iter_worklist, i);
}
}
while ((i = ir_bitqueue_pop(worklist)) >= 0) {
IR_ASSERT(_values[i].op == IR_MERGE);
ir_sccp_remove_unfeasible_merge_inputs(ctx, _values, i, _values[i].op1);
}
}
/***************************/
/* Iterative Optimizations */
/***************************/
static ir_ref ir_find1(ir_ctx *ctx, uint32_t optx, ir_ref op1)
{
IR_ASSERT(!IR_IS_CONST_REF(op1));
ir_use_list *use_list = &ctx->use_lists[op1];
ir_ref *p, n = use_list->count;
for (p = ctx->use_edges + use_list->refs; n > 0; p++, n--) {
ir_ref use = *p;
ir_insn *use_insn = &ctx->ir_base[use];
if (use_insn->optx == optx) {
IR_ASSERT(use_insn->op1 == op1);
return use;
}
}
return IR_UNUSED;
}
static void ir_iter_remove_insn(ir_ctx *ctx, ir_ref ref, ir_bitqueue *worklist)
{
ir_ref j, n, *p;
ir_insn *insn;
CLEAR_USES(ref);
insn = &ctx->ir_base[ref];
n = insn->inputs_count;
insn->opt = IR_NOP; /* keep "inputs_count" */
for (j = 1, p = insn->ops + j; j <= n; j++, p++) {
ir_ref input = *p;
*p = IR_UNUSED;
if (input > 0) {
ir_use_list_remove_all(ctx, input, ref);
if (ir_is_dead(ctx, input)) {
/* schedule DCE */
ir_bitqueue_add(worklist, input);
} else if (ctx->ir_base[input].op == IR_PHI && ctx->use_lists[input].count == 1) {
/* try to optimize PHI into ABS/MIN/MAX/COND */
ir_bitqueue_add(worklist, ctx->ir_base[input].op1);
}
}
}
}
static void ir_iter_replace_insn(ir_ctx *ctx, ir_ref ref, ir_ref new_ref, ir_bitqueue *worklist)
{
ir_ref i, j, n, *p, use;
ir_insn *insn;
ir_use_list *use_list;
IR_ASSERT(ref != new_ref);
insn = &ctx->ir_base[ref];
n = insn->inputs_count;
insn->opt = IR_NOP; /* keep "inputs_count" */
for (j = 1, p = insn->ops + 1; j <= n; j++, p++) {
ir_ref input = *p;
*p = IR_UNUSED;
if (input > 0) {
ir_use_list_remove_all(ctx, input, ref);
if (ir_is_dead(ctx, input)) {
/* schedule DCE */
ir_bitqueue_add(worklist, input);
} else if (ctx->ir_base[input].op == IR_PHI && ctx->use_lists[input].count == 1) {
/* try to optimize PHI into ABS/MIN/MAX/COND */
ir_bitqueue_add(worklist, input);
}
}
}