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
|
//===-- LegalizeTypes.cpp - Common code for DAG type legalizer ------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the SelectionDAG::LegalizeTypes method. It transforms
// an arbitrary well-formed SelectionDAG to only consist of legal types. This
// is common code shared among the LegalizeTypes*.cpp files.
//
//===----------------------------------------------------------------------===//
#include "LegalizeTypes.h"
#include "llvm/CallingConv.h"
#include "llvm/Target/TargetData.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
static cl::opt<bool>
EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden);
/// PerformExpensiveChecks - Do extensive, expensive, sanity checking.
void DAGTypeLegalizer::PerformExpensiveChecks() {
// If a node is not processed, then none of its values should be mapped by any
// of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
// If a node is processed, then each value with an illegal type must be mapped
// by exactly one of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
// Values with a legal type may be mapped by ReplacedValues, but not by any of
// the other maps.
// Note that these invariants may not hold momentarily when processing a node:
// the node being processed may be put in a map before being marked Processed.
// Note that it is possible to have nodes marked NewNode in the DAG. This can
// occur in two ways. Firstly, a node may be created during legalization but
// never passed to the legalization core. This is usually due to the implicit
// folding that occurs when using the DAG.getNode operators. Secondly, a new
// node may be passed to the legalization core, but when analyzed may morph
// into a different node, leaving the original node as a NewNode in the DAG.
// A node may morph if one of its operands changes during analysis. Whether
// it actually morphs or not depends on whether, after updating its operands,
// it is equivalent to an existing node: if so, it morphs into that existing
// node (CSE). An operand can change during analysis if the operand is a new
// node that morphs, or it is a processed value that was mapped to some other
// value (as recorded in ReplacedValues) in which case the operand is turned
// into that other value. If a node morphs then the node it morphed into will
// be used instead of it for legalization, however the original node continues
// to live on in the DAG.
// The conclusion is that though there may be nodes marked NewNode in the DAG,
// all uses of such nodes are also marked NewNode: the result is a fungus of
// NewNodes growing on top of the useful nodes, and perhaps using them, but
// not used by them.
// If a value is mapped by ReplacedValues, then it must have no uses, except
// by nodes marked NewNode (see above).
// The final node obtained by mapping by ReplacedValues is not marked NewNode.
// Note that ReplacedValues should be applied iteratively.
// Note that the ReplacedValues map may also map deleted nodes (by iterating
// over the DAG we never dereference deleted nodes). This means that it may
// also map nodes marked NewNode if the deallocated memory was reallocated as
// another node, and that new node was not seen by the LegalizeTypes machinery
// (for example because it was created but not used). In general, we cannot
// distinguish between new nodes and deleted nodes.
SmallVector<SDNode*, 16> NewNodes;
for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
E = DAG.allnodes_end(); I != E; ++I) {
// Remember nodes marked NewNode - they are subject to extra checking below.
if (I->getNodeId() == NewNode)
NewNodes.push_back(I);
for (unsigned i = 0, e = I->getNumValues(); i != e; ++i) {
SDValue Res(I, i);
bool Failed = false;
unsigned Mapped = 0;
if (ReplacedValues.find(Res) != ReplacedValues.end()) {
Mapped |= 1;
// Check that remapped values are only used by nodes marked NewNode.
for (SDNode::use_iterator UI = I->use_begin(), UE = I->use_end();
UI != UE; ++UI)
if (UI.getUse().getResNo() == i)
assert(UI->getNodeId() == NewNode &&
"Remapped value has non-trivial use!");
// Check that the final result of applying ReplacedValues is not
// marked NewNode.
SDValue NewVal = ReplacedValues[Res];
DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(NewVal);
while (I != ReplacedValues.end()) {
NewVal = I->second;
I = ReplacedValues.find(NewVal);
}
assert(NewVal.getNode()->getNodeId() != NewNode &&
"ReplacedValues maps to a new node!");
}
if (PromotedIntegers.find(Res) != PromotedIntegers.end())
Mapped |= 2;
if (SoftenedFloats.find(Res) != SoftenedFloats.end())
Mapped |= 4;
if (ScalarizedVectors.find(Res) != ScalarizedVectors.end())
Mapped |= 8;
if (ExpandedIntegers.find(Res) != ExpandedIntegers.end())
Mapped |= 16;
if (ExpandedFloats.find(Res) != ExpandedFloats.end())
Mapped |= 32;
if (SplitVectors.find(Res) != SplitVectors.end())
Mapped |= 64;
if (WidenedVectors.find(Res) != WidenedVectors.end())
Mapped |= 128;
if (I->getNodeId() != Processed) {
// Since we allow ReplacedValues to map deleted nodes, it may map nodes
// marked NewNode too, since a deleted node may have been reallocated as
// another node that has not been seen by the LegalizeTypes machinery.
if ((I->getNodeId() == NewNode && Mapped > 1) ||
(I->getNodeId() != NewNode && Mapped != 0)) {
errs() << "Unprocessed value in a map!";
Failed = true;
}
} else if (isTypeLegal(Res.getValueType()) || IgnoreNodeResults(I)) {
if (Mapped > 1) {
errs() << "Value with legal type was transformed!";
Failed = true;
}
} else {
if (Mapped == 0) {
errs() << "Processed value not in any map!";
Failed = true;
} else if (Mapped & (Mapped - 1)) {
errs() << "Value in multiple maps!";
Failed = true;
}
}
if (Failed) {
if (Mapped & 1)
errs() << " ReplacedValues";
if (Mapped & 2)
errs() << " PromotedIntegers";
if (Mapped & 4)
errs() << " SoftenedFloats";
if (Mapped & 8)
errs() << " ScalarizedVectors";
if (Mapped & 16)
errs() << " ExpandedIntegers";
if (Mapped & 32)
errs() << " ExpandedFloats";
if (Mapped & 64)
errs() << " SplitVectors";
if (Mapped & 128)
errs() << " WidenedVectors";
errs() << "\n";
llvm_unreachable(0);
}
}
}
// Checked that NewNodes are only used by other NewNodes.
for (unsigned i = 0, e = NewNodes.size(); i != e; ++i) {
SDNode *N = NewNodes[i];
for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
UI != UE; ++UI)
assert(UI->getNodeId() == NewNode && "NewNode used by non-NewNode!");
}
}
/// run - This is the main entry point for the type legalizer. This does a
/// top-down traversal of the dag, legalizing types as it goes. Returns "true"
/// if it made any changes.
bool DAGTypeLegalizer::run() {
bool Changed = false;
// Create a dummy node (which is not added to allnodes), that adds a reference
// to the root node, preventing it from being deleted, and tracking any
// changes of the root.
HandleSDNode Dummy(DAG.getRoot());
Dummy.setNodeId(Unanalyzed);
// The root of the dag may dangle to deleted nodes until the type legalizer is
// done. Set it to null to avoid confusion.
DAG.setRoot(SDValue());
// Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess'
// (and remembering them) if they are leaves and assigning 'Unanalyzed' if
// non-leaves.
for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
E = DAG.allnodes_end(); I != E; ++I) {
if (I->getNumOperands() == 0) {
I->setNodeId(ReadyToProcess);
Worklist.push_back(I);
} else {
I->setNodeId(Unanalyzed);
}
}
// Now that we have a set of nodes to process, handle them all.
while (!Worklist.empty()) {
#ifndef XDEBUG
if (EnableExpensiveChecks)
#endif
PerformExpensiveChecks();
SDNode *N = Worklist.back();
Worklist.pop_back();
assert(N->getNodeId() == ReadyToProcess &&
"Node should be ready if on worklist!");
if (IgnoreNodeResults(N))
goto ScanOperands;
// Scan the values produced by the node, checking to see if any result
// types are illegal.
for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) {
EVT ResultVT = N->getValueType(i);
switch (getTypeAction(ResultVT)) {
default:
assert(false && "Unknown action!");
case Legal:
break;
// The following calls must take care of *all* of the node's results,
// not just the illegal result they were passed (this includes results
// with a legal type). Results can be remapped using ReplaceValueWith,
// or their promoted/expanded/etc values registered in PromotedIntegers,
// ExpandedIntegers etc.
case PromoteInteger:
PromoteIntegerResult(N, i);
Changed = true;
goto NodeDone;
case ExpandInteger:
ExpandIntegerResult(N, i);
Changed = true;
goto NodeDone;
case SoftenFloat:
SoftenFloatResult(N, i);
Changed = true;
goto NodeDone;
case ExpandFloat:
ExpandFloatResult(N, i);
Changed = true;
goto NodeDone;
case ScalarizeVector:
ScalarizeVectorResult(N, i);
Changed = true;
goto NodeDone;
case SplitVector:
SplitVectorResult(N, i);
Changed = true;
goto NodeDone;
case WidenVector:
WidenVectorResult(N, i);
Changed = true;
goto NodeDone;
}
}
ScanOperands:
// Scan the operand list for the node, handling any nodes with operands that
// are illegal.
{
unsigned NumOperands = N->getNumOperands();
bool NeedsReanalyzing = false;
unsigned i;
for (i = 0; i != NumOperands; ++i) {
if (IgnoreNodeResults(N->getOperand(i).getNode()))
continue;
EVT OpVT = N->getOperand(i).getValueType();
switch (getTypeAction(OpVT)) {
default:
assert(false && "Unknown action!");
case Legal:
continue;
// The following calls must either replace all of the node's results
// using ReplaceValueWith, and return "false"; or update the node's
// operands in place, and return "true".
case PromoteInteger:
NeedsReanalyzing = PromoteIntegerOperand(N, i);
Changed = true;
break;
case ExpandInteger:
NeedsReanalyzing = ExpandIntegerOperand(N, i);
Changed = true;
break;
case SoftenFloat:
NeedsReanalyzing = SoftenFloatOperand(N, i);
Changed = true;
break;
case ExpandFloat:
NeedsReanalyzing = ExpandFloatOperand(N, i);
Changed = true;
break;
case ScalarizeVector:
NeedsReanalyzing = ScalarizeVectorOperand(N, i);
Changed = true;
break;
case SplitVector:
NeedsReanalyzing = SplitVectorOperand(N, i);
Changed = true;
break;
case WidenVector:
NeedsReanalyzing = WidenVectorOperand(N, i);
Changed = true;
break;
}
break;
}
// The sub-method updated N in place. Check to see if any operands are new,
// and if so, mark them. If the node needs revisiting, don't add all users
// to the worklist etc.
if (NeedsReanalyzing) {
assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
N->setNodeId(NewNode);
// Recompute the NodeId and correct processed operands, adding the node to
// the worklist if ready.
SDNode *M = AnalyzeNewNode(N);
if (M == N)
// The node didn't morph - nothing special to do, it will be revisited.
continue;
// The node morphed - this is equivalent to legalizing by replacing every
// value of N with the corresponding value of M. So do that now.
assert(N->getNumValues() == M->getNumValues() &&
"Node morphing changed the number of results!");
for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
// Replacing the value takes care of remapping the new value.
ReplaceValueWith(SDValue(N, i), SDValue(M, i));
assert(N->getNodeId() == NewNode && "Unexpected node state!");
// The node continues to live on as part of the NewNode fungus that
// grows on top of the useful nodes. Nothing more needs to be done
// with it - move on to the next node.
continue;
}
if (i == NumOperands) {
DEBUG(errs() << "Legally typed node: "; N->dump(&DAG); errs() << "\n");
}
}
NodeDone:
// If we reach here, the node was processed, potentially creating new nodes.
// Mark it as processed and add its users to the worklist as appropriate.
assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
N->setNodeId(Processed);
for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end();
UI != E; ++UI) {
SDNode *User = *UI;
int NodeId = User->getNodeId();
// This node has two options: it can either be a new node or its Node ID
// may be a count of the number of operands it has that are not ready.
if (NodeId > 0) {
User->setNodeId(NodeId-1);
// If this was the last use it was waiting on, add it to the ready list.
if (NodeId-1 == ReadyToProcess)
Worklist.push_back(User);
continue;
}
// If this is an unreachable new node, then ignore it. If it ever becomes
// reachable by being used by a newly created node then it will be handled
// by AnalyzeNewNode.
if (NodeId == NewNode)
continue;
// Otherwise, this node is new: this is the first operand of it that
// became ready. Its new NodeId is the number of operands it has minus 1
// (as this node is now processed).
assert(NodeId == Unanalyzed && "Unknown node ID!");
User->setNodeId(User->getNumOperands() - 1);
// If the node only has a single operand, it is now ready.
if (User->getNumOperands() == 1)
Worklist.push_back(User);
}
}
#ifndef XDEBUG
if (EnableExpensiveChecks)
#endif
PerformExpensiveChecks();
// If the root changed (e.g. it was a dead load) update the root.
DAG.setRoot(Dummy.getValue());
// Remove dead nodes. This is important to do for cleanliness but also before
// the checking loop below. Implicit folding by the DAG.getNode operators and
// node morphing can cause unreachable nodes to be around with their flags set
// to new.
DAG.RemoveDeadNodes();
// In a debug build, scan all the nodes to make sure we found them all. This
// ensures that there are no cycles and that everything got processed.
#ifndef NDEBUG
for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
E = DAG.allnodes_end(); I != E; ++I) {
bool Failed = false;
// Check that all result types are legal.
if (!IgnoreNodeResults(I))
for (unsigned i = 0, NumVals = I->getNumValues(); i < NumVals; ++i)
if (!isTypeLegal(I->getValueType(i))) {
errs() << "Result type " << i << " illegal!\n";
Failed = true;
}
// Check that all operand types are legal.
for (unsigned i = 0, NumOps = I->getNumOperands(); i < NumOps; ++i)
if (!IgnoreNodeResults(I->getOperand(i).getNode()) &&
!isTypeLegal(I->getOperand(i).getValueType())) {
errs() << "Operand type " << i << " illegal!\n";
Failed = true;
}
if (I->getNodeId() != Processed) {
if (I->getNodeId() == NewNode)
errs() << "New node not analyzed?\n";
else if (I->getNodeId() == Unanalyzed)
errs() << "Unanalyzed node not noticed?\n";
else if (I->getNodeId() > 0)
errs() << "Operand not processed?\n";
else if (I->getNodeId() == ReadyToProcess)
errs() << "Not added to worklist?\n";
Failed = true;
}
if (Failed) {
I->dump(&DAG); errs() << "\n";
llvm_unreachable(0);
}
}
#endif
return Changed;
}
/// AnalyzeNewNode - The specified node is the root of a subtree of potentially
/// new nodes. Correct any processed operands (this may change the node) and
/// calculate the NodeId. If the node itself changes to a processed node, it
/// is not remapped - the caller needs to take care of this.
/// Returns the potentially changed node.
SDNode *DAGTypeLegalizer::AnalyzeNewNode(SDNode *N) {
// If this was an existing node that is already done, we're done.
if (N->getNodeId() != NewNode && N->getNodeId() != Unanalyzed)
return N;
// Remove any stale map entries.
ExpungeNode(N);
// Okay, we know that this node is new. Recursively walk all of its operands
// to see if they are new also. The depth of this walk is bounded by the size
// of the new tree that was constructed (usually 2-3 nodes), so we don't worry
// about revisiting of nodes.
//
// As we walk the operands, keep track of the number of nodes that are
// processed. If non-zero, this will become the new nodeid of this node.
// Operands may morph when they are analyzed. If so, the node will be
// updated after all operands have been analyzed. Since this is rare,
// the code tries to minimize overhead in the non-morphing case.
SmallVector<SDValue, 8> NewOps;
unsigned NumProcessed = 0;
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
SDValue OrigOp = N->getOperand(i);
SDValue Op = OrigOp;
AnalyzeNewValue(Op); // Op may morph.
if (Op.getNode()->getNodeId() == Processed)
++NumProcessed;
if (!NewOps.empty()) {
// Some previous operand changed. Add this one to the list.
NewOps.push_back(Op);
} else if (Op != OrigOp) {
// This is the first operand to change - add all operands so far.
NewOps.insert(NewOps.end(), N->op_begin(), N->op_begin() + i);
NewOps.push_back(Op);
}
}
// Some operands changed - update the node.
if (!NewOps.empty()) {
SDNode *M = DAG.UpdateNodeOperands(SDValue(N, 0), &NewOps[0],
NewOps.size()).getNode();
if (M != N) {
// The node morphed into a different node. Normally for this to happen
// the original node would have to be marked NewNode. However this can
// in theory momentarily not be the case while ReplaceValueWith is doing
// its stuff. Mark the original node NewNode to help sanity checking.
N->setNodeId(NewNode);
if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed)
// It morphed into a previously analyzed node - nothing more to do.
return M;
// It morphed into a different new node. Do the equivalent of passing
// it to AnalyzeNewNode: expunge it and calculate the NodeId. No need
// to remap the operands, since they are the same as the operands we
// remapped above.
N = M;
ExpungeNode(N);
}
}
// Calculate the NodeId.
N->setNodeId(N->getNumOperands() - NumProcessed);
if (N->getNodeId() == ReadyToProcess)
Worklist.push_back(N);
return N;
}
/// AnalyzeNewValue - Call AnalyzeNewNode, updating the node in Val if needed.
/// If the node changes to a processed node, then remap it.
void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) {
Val.setNode(AnalyzeNewNode(Val.getNode()));
if (Val.getNode()->getNodeId() == Processed)
// We were passed a processed node, or it morphed into one - remap it.
RemapValue(Val);
}
/// ExpungeNode - If N has a bogus mapping in ReplacedValues, eliminate it.
/// This can occur when a node is deleted then reallocated as a new node -
/// the mapping in ReplacedValues applies to the deleted node, not the new
/// one.
/// The only map that can have a deleted node as a source is ReplacedValues.
/// Other maps can have deleted nodes as targets, but since their looked-up
/// values are always immediately remapped using RemapValue, resulting in a
/// not-deleted node, this is harmless as long as ReplacedValues/RemapValue
/// always performs correct mappings. In order to keep the mapping correct,
/// ExpungeNode should be called on any new nodes *before* adding them as
/// either source or target to ReplacedValues (which typically means calling
/// Expunge when a new node is first seen, since it may no longer be marked
/// NewNode by the time it is added to ReplacedValues).
void DAGTypeLegalizer::ExpungeNode(SDNode *N) {
if (N->getNodeId() != NewNode)
return;
// If N is not remapped by ReplacedValues then there is nothing to do.
unsigned i, e;
for (i = 0, e = N->getNumValues(); i != e; ++i)
if (ReplacedValues.find(SDValue(N, i)) != ReplacedValues.end())
break;
if (i == e)
return;
// Remove N from all maps - this is expensive but rare.
for (DenseMap<SDValue, SDValue>::iterator I = PromotedIntegers.begin(),
E = PromotedIntegers.end(); I != E; ++I) {
assert(I->first.getNode() != N);
RemapValue(I->second);
}
for (DenseMap<SDValue, SDValue>::iterator I = SoftenedFloats.begin(),
E = SoftenedFloats.end(); I != E; ++I) {
assert(I->first.getNode() != N);
RemapValue(I->second);
}
for (DenseMap<SDValue, SDValue>::iterator I = ScalarizedVectors.begin(),
E = ScalarizedVectors.end(); I != E; ++I) {
assert(I->first.getNode() != N);
RemapValue(I->second);
}
for (DenseMap<SDValue, SDValue>::iterator I = WidenedVectors.begin(),
E = WidenedVectors.end(); I != E; ++I) {
assert(I->first.getNode() != N);
RemapValue(I->second);
}
for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator
I = ExpandedIntegers.begin(), E = ExpandedIntegers.end(); I != E; ++I){
assert(I->first.getNode() != N);
RemapValue(I->second.first);
RemapValue(I->second.second);
}
for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator
I = ExpandedFloats.begin(), E = ExpandedFloats.end(); I != E; ++I) {
assert(I->first.getNode() != N);
RemapValue(I->second.first);
RemapValue(I->second.second);
}
for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator
I = SplitVectors.begin(), E = SplitVectors.end(); I != E; ++I) {
assert(I->first.getNode() != N);
RemapValue(I->second.first);
RemapValue(I->second.second);
}
for (DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.begin(),
E = ReplacedValues.end(); I != E; ++I)
RemapValue(I->second);
for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
ReplacedValues.erase(SDValue(N, i));
}
/// RemapValue - If the specified value was already legalized to another value,
/// replace it by that value.
void DAGTypeLegalizer::RemapValue(SDValue &N) {
DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(N);
if (I != ReplacedValues.end()) {
// Use path compression to speed up future lookups if values get multiply
// replaced with other values.
RemapValue(I->second);
N = I->second;
assert(N.getNode()->getNodeId() != NewNode && "Mapped to new node!");
}
}
namespace {
/// NodeUpdateListener - This class is a DAGUpdateListener that listens for
/// updates to nodes and recomputes their ready state.
class NodeUpdateListener : public SelectionDAG::DAGUpdateListener {
DAGTypeLegalizer &DTL;
SmallSetVector<SDNode*, 16> &NodesToAnalyze;
public:
explicit NodeUpdateListener(DAGTypeLegalizer &dtl,
SmallSetVector<SDNode*, 16> &nta)
: DTL(dtl), NodesToAnalyze(nta) {}
virtual void NodeDeleted(SDNode *N, SDNode *E) {
assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
N->getNodeId() != DAGTypeLegalizer::Processed &&
"Invalid node ID for RAUW deletion!");
// It is possible, though rare, for the deleted node N to occur as a
// target in a map, so note the replacement N -> E in ReplacedValues.
assert(E && "Node not replaced?");
DTL.NoteDeletion(N, E);
// In theory the deleted node could also have been scheduled for analysis.
// So remove it from the set of nodes which will be analyzed.
NodesToAnalyze.remove(N);
// In general nothing needs to be done for E, since it didn't change but
// only gained new uses. However N -> E was just added to ReplacedValues,
// and the result of a ReplacedValues mapping is not allowed to be marked
// NewNode. So if E is marked NewNode, then it needs to be analyzed.
if (E->getNodeId() == DAGTypeLegalizer::NewNode)
NodesToAnalyze.insert(E);
}
virtual void NodeUpdated(SDNode *N) {
// Node updates can mean pretty much anything. It is possible that an
// operand was set to something already processed (f.e.) in which case
// this node could become ready. Recompute its flags.
assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
N->getNodeId() != DAGTypeLegalizer::Processed &&
"Invalid node ID for RAUW deletion!");
N->setNodeId(DAGTypeLegalizer::NewNode);
NodesToAnalyze.insert(N);
}
};
}
/// ReplaceValueWith - The specified value was legalized to the specified other
/// value. Update the DAG and NodeIds replacing any uses of From to use To
/// instead.
void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) {
assert(From.getNode() != To.getNode() && "Potential legalization loop!");
// If expansion produced new nodes, make sure they are properly marked.
ExpungeNode(From.getNode());
AnalyzeNewValue(To); // Expunges To.
// Anything that used the old node should now use the new one. Note that this
// can potentially cause recursive merging.
SmallSetVector<SDNode*, 16> NodesToAnalyze;
NodeUpdateListener NUL(*this, NodesToAnalyze);
DAG.ReplaceAllUsesOfValueWith(From, To, &NUL);
// The old node may still be present in a map like ExpandedIntegers or
// PromotedIntegers. Inform maps about the replacement.
ReplacedValues[From] = To;
// Process the list of nodes that need to be reanalyzed.
while (!NodesToAnalyze.empty()) {
SDNode *N = NodesToAnalyze.back();
NodesToAnalyze.pop_back();
if (N->getNodeId() != DAGTypeLegalizer::NewNode)
// The node was analyzed while reanalyzing an earlier node - it is safe to
// skip. Note that this is not a morphing node - otherwise it would still
// be marked NewNode.
continue;
// Analyze the node's operands and recalculate the node ID.
SDNode *M = AnalyzeNewNode(N);
if (M != N) {
// The node morphed into a different node. Make everyone use the new node
// instead.
assert(M->getNodeId() != NewNode && "Analysis resulted in NewNode!");
assert(N->getNumValues() == M->getNumValues() &&
"Node morphing changed the number of results!");
for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) {
SDValue OldVal(N, i);
SDValue NewVal(M, i);
if (M->getNodeId() == Processed)
RemapValue(NewVal);
DAG.ReplaceAllUsesOfValueWith(OldVal, NewVal, &NUL);
}
// The original node continues to exist in the DAG, marked NewNode.
}
}
}
void DAGTypeLegalizer::SetPromotedInteger(SDValue Op, SDValue Result) {
assert(Result.getValueType() == TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
"Invalid type for promoted integer");
AnalyzeNewValue(Result);
SDValue &OpEntry = PromotedIntegers[Op];
assert(OpEntry.getNode() == 0 && "Node is already promoted!");
OpEntry = Result;
}
void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) {
assert(Result.getValueType() == TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
"Invalid type for softened float");
AnalyzeNewValue(Result);
SDValue &OpEntry = SoftenedFloats[Op];
assert(OpEntry.getNode() == 0 && "Node is already converted to integer!");
OpEntry = Result;
}
void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) {
assert(Result.getValueType() == Op.getValueType().getVectorElementType() &&
"Invalid type for scalarized vector");
AnalyzeNewValue(Result);
SDValue &OpEntry = ScalarizedVectors[Op];
assert(OpEntry.getNode() == 0 && "Node is already scalarized!");
OpEntry = Result;
}
void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo,
SDValue &Hi) {
std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op];
RemapValue(Entry.first);
RemapValue(Entry.second);
assert(Entry.first.getNode() && "Operand isn't expanded");
Lo = Entry.first;
Hi = Entry.second;
}
void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo,
SDValue Hi) {
assert(Lo.getValueType() == TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
Hi.getValueType() == Lo.getValueType() &&
"Invalid type for expanded integer");
// Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
AnalyzeNewValue(Lo);
AnalyzeNewValue(Hi);
// Remember that this is the result of the node.
std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op];
assert(Entry.first.getNode() == 0 && "Node already expanded");
Entry.first = Lo;
Entry.second = Hi;
}
void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo,
SDValue &Hi) {
std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op];
RemapValue(Entry.first);
RemapValue(Entry.second);
assert(Entry.first.getNode() && "Operand isn't expanded");
Lo = Entry.first;
Hi = Entry.second;
}
void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo,
SDValue Hi) {
assert(Lo.getValueType() == TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
Hi.getValueType() == Lo.getValueType() &&
"Invalid type for expanded float");
// Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
AnalyzeNewValue(Lo);
AnalyzeNewValue(Hi);
// Remember that this is the result of the node.
std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op];
assert(Entry.first.getNode() == 0 && "Node already expanded");
Entry.first = Lo;
Entry.second = Hi;
}
void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo,
SDValue &Hi) {
std::pair<SDValue, SDValue> &Entry = SplitVectors[Op];
RemapValue(Entry.first);
RemapValue(Entry.second);
assert(Entry.first.getNode() && "Operand isn't split");
Lo = Entry.first;
Hi = Entry.second;
}
void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo,
SDValue Hi) {
assert(Lo.getValueType().getVectorElementType() ==
Op.getValueType().getVectorElementType() &&
2*Lo.getValueType().getVectorNumElements() ==
Op.getValueType().getVectorNumElements() &&
Hi.getValueType() == Lo.getValueType() &&
"Invalid type for split vector");
// Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
AnalyzeNewValue(Lo);
AnalyzeNewValue(Hi);
// Remember that this is the result of the node.
std::pair<SDValue, SDValue> &Entry = SplitVectors[Op];
assert(Entry.first.getNode() == 0 && "Node already split");
Entry.first = Lo;
Entry.second = Hi;
}
void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) {
assert(Result.getValueType() == TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
"Invalid type for widened vector");
AnalyzeNewValue(Result);
SDValue &OpEntry = WidenedVectors[Op];
assert(OpEntry.getNode() == 0 && "Node already widened!");
OpEntry = Result;
}
//===----------------------------------------------------------------------===//
// Utilities.
//===----------------------------------------------------------------------===//
/// BitConvertToInteger - Convert to an integer of the same size.
SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) {
unsigned BitWidth = Op.getValueType().getSizeInBits();
return DAG.getNode(ISD::BIT_CONVERT, Op.getDebugLoc(),
EVT::getIntegerVT(*DAG.getContext(), BitWidth), Op);
}
/// BitConvertVectorToIntegerVector - Convert to a vector of integers of the
/// same size.
SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) {
assert(Op.getValueType().isVector() && "Only applies to vectors!");
unsigned EltWidth = Op.getValueType().getVectorElementType().getSizeInBits();
EVT EltNVT = EVT::getIntegerVT(*DAG.getContext(), EltWidth);
unsigned NumElts = Op.getValueType().getVectorNumElements();
return DAG.getNode(ISD::BIT_CONVERT, Op.getDebugLoc(),
EVT::getVectorVT(*DAG.getContext(), EltNVT, NumElts), Op);
}
SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op,
EVT DestVT) {
DebugLoc dl = Op.getDebugLoc();
// Create the stack frame object. Make sure it is aligned for both
// the source and destination types.
SDValue StackPtr = DAG.CreateStackTemporary(Op.getValueType(), DestVT);
// Emit a store to the stack slot.
SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Op, StackPtr, NULL, 0);
// Result is a load from the stack slot.
return DAG.getLoad(DestVT, dl, Store, StackPtr, NULL, 0);
}
/// CustomLowerNode - Replace the node's results with custom code provided
/// by the target and return "true", or do nothing and return "false".
/// The last parameter is FALSE if we are dealing with a node with legal
/// result types and illegal operand. The second parameter denotes the type of
/// illegal OperandNo in that case.
/// The last parameter being TRUE means we are dealing with a
/// node with illegal result types. The second parameter denotes the type of
/// illegal ResNo in that case.
bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) {
// See if the target wants to custom lower this node.
if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom)
return false;
SmallVector<SDValue, 8> Results;
if (LegalizeResult)
TLI.ReplaceNodeResults(N, Results, DAG);
else
TLI.LowerOperationWrapper(N, Results, DAG);
if (Results.empty())
// The target didn't want to custom lower it after all.
return false;
// Make everything that once used N's values now use those in Results instead.
assert(Results.size() == N->getNumValues() &&
"Custom lowering returned the wrong number of results!");
for (unsigned i = 0, e = Results.size(); i != e; ++i)
ReplaceValueWith(SDValue(N, i), Results[i]);
return true;
}
/// CustomWidenLowerNode - Widen the node's results with custom code provided
/// by the target and return "true", or do nothing and return "false".
bool DAGTypeLegalizer::CustomWidenLowerNode(SDNode *N, EVT VT) {
// See if the target wants to custom lower this node.
if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom)
return false;
SmallVector<SDValue, 8> Results;
TLI.ReplaceNodeResults(N, Results, DAG);
if (Results.empty())
// The target didn't want to custom widen lower its result after all.
return false;
// Update the widening map.
assert(Results.size() == N->getNumValues() &&
"Custom lowering returned the wrong number of results!");
for (unsigned i = 0, e = Results.size(); i != e; ++i)
SetWidenedVector(SDValue(N, i), Results[i]);
return true;
}
/// GetSplitDestVTs - Compute the VTs needed for the low/hi parts of a type
/// which is split into two not necessarily identical pieces.
void DAGTypeLegalizer::GetSplitDestVTs(EVT InVT, EVT &LoVT, EVT &HiVT) {
// Currently all types are split in half.
if (!InVT.isVector()) {
LoVT = HiVT = TLI.getTypeToTransformTo(*DAG.getContext(), InVT);
} else {
unsigned NumElements = InVT.getVectorNumElements();
assert(!(NumElements & 1) && "Splitting vector, but not in half!");
LoVT = HiVT = EVT::getVectorVT(*DAG.getContext(), InVT.getVectorElementType(), NumElements/2);
}
}
/// GetPairElements - Use ISD::EXTRACT_ELEMENT nodes to extract the low and
/// high parts of the given value.
void DAGTypeLegalizer::GetPairElements(SDValue Pair,
SDValue &Lo, SDValue &Hi) {
DebugLoc dl = Pair.getDebugLoc();
EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), Pair.getValueType());
Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair,
DAG.getIntPtrConstant(0));
Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair,
DAG.getIntPtrConstant(1));
}
SDValue DAGTypeLegalizer::GetVectorElementPointer(SDValue VecPtr, EVT EltVT,
SDValue Index) {
DebugLoc dl = Index.getDebugLoc();
// Make sure the index type is big enough to compute in.
if (Index.getValueType().bitsGT(TLI.getPointerTy()))
Index = DAG.getNode(ISD::TRUNCATE, dl, TLI.getPointerTy(), Index);
else
Index = DAG.getNode(ISD::ZERO_EXTEND, dl, TLI.getPointerTy(), Index);
// Calculate the element offset and add it to the pointer.
unsigned EltSize = EltVT.getSizeInBits() / 8; // FIXME: should be ABI size.
Index = DAG.getNode(ISD::MUL, dl, Index.getValueType(), Index,
DAG.getConstant(EltSize, Index.getValueType()));
return DAG.getNode(ISD::ADD, dl, Index.getValueType(), Index, VecPtr);
}
/// JoinIntegers - Build an integer with low bits Lo and high bits Hi.
SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) {
// Arbitrarily use dlHi for result DebugLoc
DebugLoc dlHi = Hi.getDebugLoc();
DebugLoc dlLo = Lo.getDebugLoc();
EVT LVT = Lo.getValueType();
EVT HVT = Hi.getValueType();
EVT NVT = EVT::getIntegerVT(*DAG.getContext(), LVT.getSizeInBits() + HVT.getSizeInBits());
Lo = DAG.getNode(ISD::ZERO_EXTEND, dlLo, NVT, Lo);
Hi = DAG.getNode(ISD::ANY_EXTEND, dlHi, NVT, Hi);
Hi = DAG.getNode(ISD::SHL, dlHi, NVT, Hi,
DAG.getConstant(LVT.getSizeInBits(), TLI.getPointerTy()));
return DAG.getNode(ISD::OR, dlHi, NVT, Lo, Hi);
}
/// LibCallify - Convert the node into a libcall with the same prototype.
SDValue DAGTypeLegalizer::LibCallify(RTLIB::Libcall LC, SDNode *N,
bool isSigned) {
unsigned NumOps = N->getNumOperands();
DebugLoc dl = N->getDebugLoc();
if (NumOps == 0) {
return MakeLibCall(LC, N->getValueType(0), 0, 0, isSigned, dl);
} else if (NumOps == 1) {
SDValue Op = N->getOperand(0);
return MakeLibCall(LC, N->getValueType(0), &Op, 1, isSigned, dl);
} else if (NumOps == 2) {
SDValue Ops[2] = { N->getOperand(0), N->getOperand(1) };
return MakeLibCall(LC, N->getValueType(0), Ops, 2, isSigned, dl);
}
SmallVector<SDValue, 8> Ops(NumOps);
for (unsigned i = 0; i < NumOps; ++i)
Ops[i] = N->getOperand(i);
return MakeLibCall(LC, N->getValueType(0), &Ops[0], NumOps, isSigned, dl);
}
/// MakeLibCall - Generate a libcall taking the given operands as arguments and
/// returning a result of type RetVT.
SDValue DAGTypeLegalizer::MakeLibCall(RTLIB::Libcall LC, EVT RetVT,
const SDValue *Ops, unsigned NumOps,
bool isSigned, DebugLoc dl) {
TargetLowering::ArgListTy Args;
Args.reserve(NumOps);
TargetLowering::ArgListEntry Entry;
for (unsigned i = 0; i != NumOps; ++i) {
Entry.Node = Ops[i];
Entry.Ty = Entry.Node.getValueType().getTypeForEVT(*DAG.getContext());
Entry.isSExt = isSigned;
Entry.isZExt = !isSigned;
Args.push_back(Entry);
}
SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC),
TLI.getPointerTy());
const Type *RetTy = RetVT.getTypeForEVT(*DAG.getContext());
std::pair<SDValue,SDValue> CallInfo =
TLI.LowerCallTo(DAG.getEntryNode(), RetTy, isSigned, !isSigned, false,
false, 0, TLI.getLibcallCallingConv(LC), false,
/*isReturnValueUsed=*/true,
Callee, Args, DAG, dl);
return CallInfo.first;
}
/// PromoteTargetBoolean - Promote the given target boolean to a target boolean
/// of the given type. A target boolean is an integer value, not necessarily of
/// type i1, the bits of which conform to getBooleanContents.
SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT VT) {
DebugLoc dl = Bool.getDebugLoc();
ISD::NodeType ExtendCode;
switch (TLI.getBooleanContents()) {
default:
assert(false && "Unknown BooleanContent!");
case TargetLowering::UndefinedBooleanContent:
// Extend to VT by adding rubbish bits.
ExtendCode = ISD::ANY_EXTEND;
break;
case TargetLowering::ZeroOrOneBooleanContent:
// Extend to VT by adding zero bits.
ExtendCode = ISD::ZERO_EXTEND;
break;
case TargetLowering::ZeroOrNegativeOneBooleanContent: {
// Extend to VT by copying the sign bit.
ExtendCode = ISD::SIGN_EXTEND;
break;
}
}
return DAG.getNode(ExtendCode, dl, VT, Bool);
}
/// SplitInteger - Return the lower LoVT bits of Op in Lo and the upper HiVT
/// bits in Hi.
void DAGTypeLegalizer::SplitInteger(SDValue Op,
EVT LoVT, EVT HiVT,
SDValue &Lo, SDValue &Hi) {
DebugLoc dl = Op.getDebugLoc();
assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() ==
Op.getValueType().getSizeInBits() && "Invalid integer splitting!");
Lo = DAG.getNode(ISD::TRUNCATE, dl, LoVT, Op);
Hi = DAG.getNode(ISD::SRL, dl, Op.getValueType(), Op,
DAG.getConstant(LoVT.getSizeInBits(), TLI.getPointerTy()));
Hi = DAG.getNode(ISD::TRUNCATE, dl, HiVT, Hi);
}
/// SplitInteger - Return the lower and upper halves of Op's bits in a value
/// type half the size of Op's.
void DAGTypeLegalizer::SplitInteger(SDValue Op,
SDValue &Lo, SDValue &Hi) {
EVT HalfVT = EVT::getIntegerVT(*DAG.getContext(), Op.getValueType().getSizeInBits()/2);
SplitInteger(Op, HalfVT, HalfVT, Lo, Hi);
}
//===----------------------------------------------------------------------===//
// Entry Point
//===----------------------------------------------------------------------===//
/// LegalizeTypes - This transforms the SelectionDAG into a SelectionDAG that
/// only uses types natively supported by the target. Returns "true" if it made
/// any changes.
///
/// Note that this is an involved process that may invalidate pointers into
/// the graph.
bool SelectionDAG::LegalizeTypes() {
return DAGTypeLegalizer(*this).run();
}
|