forked from chapuni/llvm
-
Notifications
You must be signed in to change notification settings - Fork 10
/
LegalizeDAG.cpp
3924 lines (3610 loc) · 162 KB
/
LegalizeDAG.cpp
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
//===-- LegalizeDAG.cpp - Implement SelectionDAG::Legalize ----------------===//
//
// 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::Legalize method.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Triple.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/DebugInfo.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
/// SelectionDAGLegalize - This takes an arbitrary SelectionDAG as input and
/// hacks on it until the target machine can handle it. This involves
/// eliminating value sizes the machine cannot handle (promoting small sizes to
/// large sizes or splitting up large values into small values) as well as
/// eliminating operations the machine cannot handle.
///
/// This code also does a small amount of optimization and recognition of idioms
/// as part of its processing. For example, if a target does not support a
/// 'setcc' instruction efficiently, but does support 'brcc' instruction, this
/// will attempt merge setcc and brc instructions into brcc's.
///
namespace {
class SelectionDAGLegalize : public SelectionDAG::DAGUpdateListener {
const TargetMachine &TM;
const TargetLowering &TLI;
SelectionDAG &DAG;
/// LegalizePosition - The iterator for walking through the node list.
SelectionDAG::allnodes_iterator LegalizePosition;
/// LegalizedNodes - The set of nodes which have already been legalized.
SmallPtrSet<SDNode *, 16> LegalizedNodes;
// Libcall insertion helpers.
public:
explicit SelectionDAGLegalize(SelectionDAG &DAG);
void LegalizeDAG();
private:
/// LegalizeOp - Legalizes the given operation.
void LegalizeOp(SDNode *Node);
SDValue OptimizeFloatStore(StoreSDNode *ST);
void LegalizeLoadOps(SDNode *Node);
void LegalizeStoreOps(SDNode *Node);
/// PerformInsertVectorEltInMemory - Some target cannot handle a variable
/// insertion index for the INSERT_VECTOR_ELT instruction. In this case, it
/// is necessary to spill the vector being inserted into to memory, perform
/// the insert there, and then read the result back.
SDValue PerformInsertVectorEltInMemory(SDValue Vec, SDValue Val,
SDValue Idx, DebugLoc dl);
SDValue ExpandINSERT_VECTOR_ELT(SDValue Vec, SDValue Val,
SDValue Idx, DebugLoc dl);
/// ShuffleWithNarrowerEltType - Return a vector shuffle operation which
/// performs the same shuffe in terms of order or result bytes, but on a type
/// whose vector element type is narrower than the original shuffle type.
/// e.g. <v4i32> <0, 1, 0, 1> -> v8i16 <0, 1, 2, 3, 0, 1, 2, 3>
SDValue ShuffleWithNarrowerEltType(EVT NVT, EVT VT, DebugLoc dl,
SDValue N1, SDValue N2,
ArrayRef<int> Mask) const;
void LegalizeSetCCCondCode(EVT VT, SDValue &LHS, SDValue &RHS, SDValue &CC,
DebugLoc dl);
SDValue ExpandLibCall(RTLIB::Libcall LC, SDNode *Node, bool isSigned);
SDValue ExpandLibCall(RTLIB::Libcall LC, EVT RetVT, const SDValue *Ops,
unsigned NumOps, bool isSigned, DebugLoc dl);
std::pair<SDValue, SDValue> ExpandChainLibCall(RTLIB::Libcall LC,
SDNode *Node, bool isSigned);
SDValue ExpandFPLibCall(SDNode *Node, RTLIB::Libcall Call_F32,
RTLIB::Libcall Call_F64, RTLIB::Libcall Call_F80,
RTLIB::Libcall Call_F128,
RTLIB::Libcall Call_PPCF128);
SDValue ExpandIntLibCall(SDNode *Node, bool isSigned,
RTLIB::Libcall Call_I8,
RTLIB::Libcall Call_I16,
RTLIB::Libcall Call_I32,
RTLIB::Libcall Call_I64,
RTLIB::Libcall Call_I128);
void ExpandDivRemLibCall(SDNode *Node, SmallVectorImpl<SDValue> &Results);
void ExpandSinCosLibCall(SDNode *Node, SmallVectorImpl<SDValue> &Results);
SDValue EmitStackConvert(SDValue SrcOp, EVT SlotVT, EVT DestVT, DebugLoc dl);
SDValue ExpandBUILD_VECTOR(SDNode *Node);
SDValue ExpandSCALAR_TO_VECTOR(SDNode *Node);
void ExpandDYNAMIC_STACKALLOC(SDNode *Node,
SmallVectorImpl<SDValue> &Results);
SDValue ExpandFCOPYSIGN(SDNode *Node);
SDValue ExpandLegalINT_TO_FP(bool isSigned, SDValue LegalOp, EVT DestVT,
DebugLoc dl);
SDValue PromoteLegalINT_TO_FP(SDValue LegalOp, EVT DestVT, bool isSigned,
DebugLoc dl);
SDValue PromoteLegalFP_TO_INT(SDValue LegalOp, EVT DestVT, bool isSigned,
DebugLoc dl);
SDValue ExpandBSWAP(SDValue Op, DebugLoc dl);
SDValue ExpandBitCount(unsigned Opc, SDValue Op, DebugLoc dl);
SDValue ExpandExtractFromVectorThroughStack(SDValue Op);
SDValue ExpandInsertToVectorThroughStack(SDValue Op);
SDValue ExpandVectorBuildThroughStack(SDNode* Node);
SDValue ExpandConstantFP(ConstantFPSDNode *CFP, bool UseCP);
std::pair<SDValue, SDValue> ExpandAtomic(SDNode *Node);
void ExpandNode(SDNode *Node);
void PromoteNode(SDNode *Node);
void ForgetNode(SDNode *N) {
LegalizedNodes.erase(N);
if (LegalizePosition == SelectionDAG::allnodes_iterator(N))
++LegalizePosition;
}
public:
// DAGUpdateListener implementation.
virtual void NodeDeleted(SDNode *N, SDNode *E) {
ForgetNode(N);
}
virtual void NodeUpdated(SDNode *N) {}
// Node replacement helpers
void ReplacedNode(SDNode *N) {
if (N->use_empty()) {
DAG.RemoveDeadNode(N);
} else {
ForgetNode(N);
}
}
void ReplaceNode(SDNode *Old, SDNode *New) {
DAG.ReplaceAllUsesWith(Old, New);
ReplacedNode(Old);
}
void ReplaceNode(SDValue Old, SDValue New) {
DAG.ReplaceAllUsesWith(Old, New);
ReplacedNode(Old.getNode());
}
void ReplaceNode(SDNode *Old, const SDValue *New) {
DAG.ReplaceAllUsesWith(Old, New);
ReplacedNode(Old);
}
};
}
/// ShuffleWithNarrowerEltType - Return a vector shuffle operation which
/// performs the same shuffe in terms of order or result bytes, but on a type
/// whose vector element type is narrower than the original shuffle type.
/// e.g. <v4i32> <0, 1, 0, 1> -> v8i16 <0, 1, 2, 3, 0, 1, 2, 3>
SDValue
SelectionDAGLegalize::ShuffleWithNarrowerEltType(EVT NVT, EVT VT, DebugLoc dl,
SDValue N1, SDValue N2,
ArrayRef<int> Mask) const {
unsigned NumMaskElts = VT.getVectorNumElements();
unsigned NumDestElts = NVT.getVectorNumElements();
unsigned NumEltsGrowth = NumDestElts / NumMaskElts;
assert(NumEltsGrowth && "Cannot promote to vector type with fewer elts!");
if (NumEltsGrowth == 1)
return DAG.getVectorShuffle(NVT, dl, N1, N2, &Mask[0]);
SmallVector<int, 8> NewMask;
for (unsigned i = 0; i != NumMaskElts; ++i) {
int Idx = Mask[i];
for (unsigned j = 0; j != NumEltsGrowth; ++j) {
if (Idx < 0)
NewMask.push_back(-1);
else
NewMask.push_back(Idx * NumEltsGrowth + j);
}
}
assert(NewMask.size() == NumDestElts && "Non-integer NumEltsGrowth?");
assert(TLI.isShuffleMaskLegal(NewMask, NVT) && "Shuffle not legal?");
return DAG.getVectorShuffle(NVT, dl, N1, N2, &NewMask[0]);
}
SelectionDAGLegalize::SelectionDAGLegalize(SelectionDAG &dag)
: SelectionDAG::DAGUpdateListener(dag),
TM(dag.getTarget()), TLI(dag.getTargetLoweringInfo()),
DAG(dag) {
}
void SelectionDAGLegalize::LegalizeDAG() {
DAG.AssignTopologicalOrder();
// Visit all the nodes. We start in topological order, so that we see
// nodes with their original operands intact. Legalization can produce
// new nodes which may themselves need to be legalized. Iterate until all
// nodes have been legalized.
for (;;) {
bool AnyLegalized = false;
for (LegalizePosition = DAG.allnodes_end();
LegalizePosition != DAG.allnodes_begin(); ) {
--LegalizePosition;
SDNode *N = LegalizePosition;
if (LegalizedNodes.insert(N)) {
AnyLegalized = true;
LegalizeOp(N);
}
}
if (!AnyLegalized)
break;
}
// Remove dead nodes now.
DAG.RemoveDeadNodes();
}
/// ExpandConstantFP - Expands the ConstantFP node to an integer constant or
/// a load from the constant pool.
SDValue
SelectionDAGLegalize::ExpandConstantFP(ConstantFPSDNode *CFP, bool UseCP) {
bool Extend = false;
DebugLoc dl = CFP->getDebugLoc();
// If a FP immediate is precise when represented as a float and if the
// target can do an extending load from float to double, we put it into
// the constant pool as a float, even if it's is statically typed as a
// double. This shrinks FP constants and canonicalizes them for targets where
// an FP extending load is the same cost as a normal load (such as on the x87
// fp stack or PPC FP unit).
EVT VT = CFP->getValueType(0);
ConstantFP *LLVMC = const_cast<ConstantFP*>(CFP->getConstantFPValue());
if (!UseCP) {
assert((VT == MVT::f64 || VT == MVT::f32) && "Invalid type expansion");
return DAG.getConstant(LLVMC->getValueAPF().bitcastToAPInt(),
(VT == MVT::f64) ? MVT::i64 : MVT::i32);
}
EVT OrigVT = VT;
EVT SVT = VT;
while (SVT != MVT::f32) {
SVT = (MVT::SimpleValueType)(SVT.getSimpleVT().SimpleTy - 1);
if (ConstantFPSDNode::isValueValidForType(SVT, CFP->getValueAPF()) &&
// Only do this if the target has a native EXTLOAD instruction from
// smaller type.
TLI.isLoadExtLegal(ISD::EXTLOAD, SVT) &&
TLI.ShouldShrinkFPConstant(OrigVT)) {
Type *SType = SVT.getTypeForEVT(*DAG.getContext());
LLVMC = cast<ConstantFP>(ConstantExpr::getFPTrunc(LLVMC, SType));
VT = SVT;
Extend = true;
}
}
SDValue CPIdx = DAG.getConstantPool(LLVMC, TLI.getPointerTy());
unsigned Alignment = cast<ConstantPoolSDNode>(CPIdx)->getAlignment();
if (Extend) {
SDValue Result =
DAG.getExtLoad(ISD::EXTLOAD, dl, OrigVT,
DAG.getEntryNode(),
CPIdx, MachinePointerInfo::getConstantPool(),
VT, false, false, Alignment);
return Result;
}
SDValue Result =
DAG.getLoad(OrigVT, dl, DAG.getEntryNode(), CPIdx,
MachinePointerInfo::getConstantPool(), false, false, false,
Alignment);
return Result;
}
/// ExpandUnalignedStore - Expands an unaligned store to 2 half-size stores.
static void ExpandUnalignedStore(StoreSDNode *ST, SelectionDAG &DAG,
const TargetLowering &TLI,
SelectionDAGLegalize *DAGLegalize) {
assert(ST->getAddressingMode() == ISD::UNINDEXED &&
"unaligned indexed stores not implemented!");
SDValue Chain = ST->getChain();
SDValue Ptr = ST->getBasePtr();
SDValue Val = ST->getValue();
EVT VT = Val.getValueType();
int Alignment = ST->getAlignment();
DebugLoc dl = ST->getDebugLoc();
if (ST->getMemoryVT().isFloatingPoint() ||
ST->getMemoryVT().isVector()) {
EVT intVT = EVT::getIntegerVT(*DAG.getContext(), VT.getSizeInBits());
if (TLI.isTypeLegal(intVT)) {
// Expand to a bitconvert of the value to the integer type of the
// same size, then a (misaligned) int store.
// FIXME: Does not handle truncating floating point stores!
SDValue Result = DAG.getNode(ISD::BITCAST, dl, intVT, Val);
Result = DAG.getStore(Chain, dl, Result, Ptr, ST->getPointerInfo(),
ST->isVolatile(), ST->isNonTemporal(), Alignment);
DAGLegalize->ReplaceNode(SDValue(ST, 0), Result);
return;
}
// Do a (aligned) store to a stack slot, then copy from the stack slot
// to the final destination using (unaligned) integer loads and stores.
EVT StoredVT = ST->getMemoryVT();
MVT RegVT =
TLI.getRegisterType(*DAG.getContext(),
EVT::getIntegerVT(*DAG.getContext(),
StoredVT.getSizeInBits()));
unsigned StoredBytes = StoredVT.getSizeInBits() / 8;
unsigned RegBytes = RegVT.getSizeInBits() / 8;
unsigned NumRegs = (StoredBytes + RegBytes - 1) / RegBytes;
// Make sure the stack slot is also aligned for the register type.
SDValue StackPtr = DAG.CreateStackTemporary(StoredVT, RegVT);
// Perform the original store, only redirected to the stack slot.
SDValue Store = DAG.getTruncStore(Chain, dl,
Val, StackPtr, MachinePointerInfo(),
StoredVT, false, false, 0);
SDValue Increment = DAG.getConstant(RegBytes, TLI.getPointerTy());
SmallVector<SDValue, 8> Stores;
unsigned Offset = 0;
// Do all but one copies using the full register width.
for (unsigned i = 1; i < NumRegs; i++) {
// Load one integer register's worth from the stack slot.
SDValue Load = DAG.getLoad(RegVT, dl, Store, StackPtr,
MachinePointerInfo(),
false, false, false, 0);
// Store it to the final location. Remember the store.
Stores.push_back(DAG.getStore(Load.getValue(1), dl, Load, Ptr,
ST->getPointerInfo().getWithOffset(Offset),
ST->isVolatile(), ST->isNonTemporal(),
MinAlign(ST->getAlignment(), Offset)));
// Increment the pointers.
Offset += RegBytes;
StackPtr = DAG.getNode(ISD::ADD, dl, StackPtr.getValueType(), StackPtr,
Increment);
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr, Increment);
}
// The last store may be partial. Do a truncating store. On big-endian
// machines this requires an extending load from the stack slot to ensure
// that the bits are in the right place.
EVT MemVT = EVT::getIntegerVT(*DAG.getContext(),
8 * (StoredBytes - Offset));
// Load from the stack slot.
SDValue Load = DAG.getExtLoad(ISD::EXTLOAD, dl, RegVT, Store, StackPtr,
MachinePointerInfo(),
MemVT, false, false, 0);
Stores.push_back(DAG.getTruncStore(Load.getValue(1), dl, Load, Ptr,
ST->getPointerInfo()
.getWithOffset(Offset),
MemVT, ST->isVolatile(),
ST->isNonTemporal(),
MinAlign(ST->getAlignment(), Offset)));
// The order of the stores doesn't matter - say it with a TokenFactor.
SDValue Result =
DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &Stores[0],
Stores.size());
DAGLegalize->ReplaceNode(SDValue(ST, 0), Result);
return;
}
assert(ST->getMemoryVT().isInteger() &&
!ST->getMemoryVT().isVector() &&
"Unaligned store of unknown type.");
// Get the half-size VT
EVT NewStoredVT = ST->getMemoryVT().getHalfSizedIntegerVT(*DAG.getContext());
int NumBits = NewStoredVT.getSizeInBits();
int IncrementSize = NumBits / 8;
// Divide the stored value in two parts.
SDValue ShiftAmount = DAG.getConstant(NumBits,
TLI.getShiftAmountTy(Val.getValueType()));
SDValue Lo = Val;
SDValue Hi = DAG.getNode(ISD::SRL, dl, VT, Val, ShiftAmount);
// Store the two parts
SDValue Store1, Store2;
Store1 = DAG.getTruncStore(Chain, dl, TLI.isLittleEndian()?Lo:Hi, Ptr,
ST->getPointerInfo(), NewStoredVT,
ST->isVolatile(), ST->isNonTemporal(), Alignment);
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getConstant(IncrementSize, TLI.getPointerTy()));
Alignment = MinAlign(Alignment, IncrementSize);
Store2 = DAG.getTruncStore(Chain, dl, TLI.isLittleEndian()?Hi:Lo, Ptr,
ST->getPointerInfo().getWithOffset(IncrementSize),
NewStoredVT, ST->isVolatile(), ST->isNonTemporal(),
Alignment);
SDValue Result =
DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Store1, Store2);
DAGLegalize->ReplaceNode(SDValue(ST, 0), Result);
}
/// ExpandUnalignedLoad - Expands an unaligned load to 2 half-size loads.
static void
ExpandUnalignedLoad(LoadSDNode *LD, SelectionDAG &DAG,
const TargetLowering &TLI,
SDValue &ValResult, SDValue &ChainResult) {
assert(LD->getAddressingMode() == ISD::UNINDEXED &&
"unaligned indexed loads not implemented!");
SDValue Chain = LD->getChain();
SDValue Ptr = LD->getBasePtr();
EVT VT = LD->getValueType(0);
EVT LoadedVT = LD->getMemoryVT();
DebugLoc dl = LD->getDebugLoc();
if (VT.isFloatingPoint() || VT.isVector()) {
EVT intVT = EVT::getIntegerVT(*DAG.getContext(), LoadedVT.getSizeInBits());
if (TLI.isTypeLegal(intVT) && TLI.isTypeLegal(LoadedVT)) {
// Expand to a (misaligned) integer load of the same size,
// then bitconvert to floating point or vector.
SDValue newLoad = DAG.getLoad(intVT, dl, Chain, Ptr, LD->getPointerInfo(),
LD->isVolatile(),
LD->isNonTemporal(),
LD->isInvariant(), LD->getAlignment());
SDValue Result = DAG.getNode(ISD::BITCAST, dl, LoadedVT, newLoad);
if (LoadedVT != VT)
Result = DAG.getNode(VT.isFloatingPoint() ? ISD::FP_EXTEND :
ISD::ANY_EXTEND, dl, VT, Result);
ValResult = Result;
ChainResult = Chain;
return;
}
// Copy the value to a (aligned) stack slot using (unaligned) integer
// loads and stores, then do a (aligned) load from the stack slot.
MVT RegVT = TLI.getRegisterType(*DAG.getContext(), intVT);
unsigned LoadedBytes = LoadedVT.getSizeInBits() / 8;
unsigned RegBytes = RegVT.getSizeInBits() / 8;
unsigned NumRegs = (LoadedBytes + RegBytes - 1) / RegBytes;
// Make sure the stack slot is also aligned for the register type.
SDValue StackBase = DAG.CreateStackTemporary(LoadedVT, RegVT);
SDValue Increment = DAG.getConstant(RegBytes, TLI.getPointerTy());
SmallVector<SDValue, 8> Stores;
SDValue StackPtr = StackBase;
unsigned Offset = 0;
// Do all but one copies using the full register width.
for (unsigned i = 1; i < NumRegs; i++) {
// Load one integer register's worth from the original location.
SDValue Load = DAG.getLoad(RegVT, dl, Chain, Ptr,
LD->getPointerInfo().getWithOffset(Offset),
LD->isVolatile(), LD->isNonTemporal(),
LD->isInvariant(),
MinAlign(LD->getAlignment(), Offset));
// Follow the load with a store to the stack slot. Remember the store.
Stores.push_back(DAG.getStore(Load.getValue(1), dl, Load, StackPtr,
MachinePointerInfo(), false, false, 0));
// Increment the pointers.
Offset += RegBytes;
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr, Increment);
StackPtr = DAG.getNode(ISD::ADD, dl, StackPtr.getValueType(), StackPtr,
Increment);
}
// The last copy may be partial. Do an extending load.
EVT MemVT = EVT::getIntegerVT(*DAG.getContext(),
8 * (LoadedBytes - Offset));
SDValue Load = DAG.getExtLoad(ISD::EXTLOAD, dl, RegVT, Chain, Ptr,
LD->getPointerInfo().getWithOffset(Offset),
MemVT, LD->isVolatile(),
LD->isNonTemporal(),
MinAlign(LD->getAlignment(), Offset));
// Follow the load with a store to the stack slot. Remember the store.
// On big-endian machines this requires a truncating store to ensure
// that the bits end up in the right place.
Stores.push_back(DAG.getTruncStore(Load.getValue(1), dl, Load, StackPtr,
MachinePointerInfo(), MemVT,
false, false, 0));
// The order of the stores doesn't matter - say it with a TokenFactor.
SDValue TF = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, &Stores[0],
Stores.size());
// Finally, perform the original load only redirected to the stack slot.
Load = DAG.getExtLoad(LD->getExtensionType(), dl, VT, TF, StackBase,
MachinePointerInfo(), LoadedVT, false, false, 0);
// Callers expect a MERGE_VALUES node.
ValResult = Load;
ChainResult = TF;
return;
}
assert(LoadedVT.isInteger() && !LoadedVT.isVector() &&
"Unaligned load of unsupported type.");
// Compute the new VT that is half the size of the old one. This is an
// integer MVT.
unsigned NumBits = LoadedVT.getSizeInBits();
EVT NewLoadedVT;
NewLoadedVT = EVT::getIntegerVT(*DAG.getContext(), NumBits/2);
NumBits >>= 1;
unsigned Alignment = LD->getAlignment();
unsigned IncrementSize = NumBits / 8;
ISD::LoadExtType HiExtType = LD->getExtensionType();
// If the original load is NON_EXTLOAD, the hi part load must be ZEXTLOAD.
if (HiExtType == ISD::NON_EXTLOAD)
HiExtType = ISD::ZEXTLOAD;
// Load the value in two parts
SDValue Lo, Hi;
if (TLI.isLittleEndian()) {
Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, VT, Chain, Ptr, LD->getPointerInfo(),
NewLoadedVT, LD->isVolatile(),
LD->isNonTemporal(), Alignment);
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getConstant(IncrementSize, TLI.getPointerTy()));
Hi = DAG.getExtLoad(HiExtType, dl, VT, Chain, Ptr,
LD->getPointerInfo().getWithOffset(IncrementSize),
NewLoadedVT, LD->isVolatile(),
LD->isNonTemporal(), MinAlign(Alignment,IncrementSize));
} else {
Hi = DAG.getExtLoad(HiExtType, dl, VT, Chain, Ptr, LD->getPointerInfo(),
NewLoadedVT, LD->isVolatile(),
LD->isNonTemporal(), Alignment);
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getConstant(IncrementSize, TLI.getPointerTy()));
Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, VT, Chain, Ptr,
LD->getPointerInfo().getWithOffset(IncrementSize),
NewLoadedVT, LD->isVolatile(),
LD->isNonTemporal(), MinAlign(Alignment,IncrementSize));
}
// aggregate the two parts
SDValue ShiftAmount = DAG.getConstant(NumBits,
TLI.getShiftAmountTy(Hi.getValueType()));
SDValue Result = DAG.getNode(ISD::SHL, dl, VT, Hi, ShiftAmount);
Result = DAG.getNode(ISD::OR, dl, VT, Result, Lo);
SDValue TF = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
Hi.getValue(1));
ValResult = Result;
ChainResult = TF;
}
/// PerformInsertVectorEltInMemory - Some target cannot handle a variable
/// insertion index for the INSERT_VECTOR_ELT instruction. In this case, it
/// is necessary to spill the vector being inserted into to memory, perform
/// the insert there, and then read the result back.
SDValue SelectionDAGLegalize::
PerformInsertVectorEltInMemory(SDValue Vec, SDValue Val, SDValue Idx,
DebugLoc dl) {
SDValue Tmp1 = Vec;
SDValue Tmp2 = Val;
SDValue Tmp3 = Idx;
// If the target doesn't support this, we have to spill the input vector
// to a temporary stack slot, update the element, then reload it. This is
// badness. We could also load the value into a vector register (either
// with a "move to register" or "extload into register" instruction, then
// permute it into place, if the idx is a constant and if the idx is
// supported by the target.
EVT VT = Tmp1.getValueType();
EVT EltVT = VT.getVectorElementType();
EVT IdxVT = Tmp3.getValueType();
EVT PtrVT = TLI.getPointerTy();
SDValue StackPtr = DAG.CreateStackTemporary(VT);
int SPFI = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
// Store the vector.
SDValue Ch = DAG.getStore(DAG.getEntryNode(), dl, Tmp1, StackPtr,
MachinePointerInfo::getFixedStack(SPFI),
false, false, 0);
// Truncate or zero extend offset to target pointer type.
unsigned CastOpc = IdxVT.bitsGT(PtrVT) ? ISD::TRUNCATE : ISD::ZERO_EXTEND;
Tmp3 = DAG.getNode(CastOpc, dl, PtrVT, Tmp3);
// Add the offset to the index.
unsigned EltSize = EltVT.getSizeInBits()/8;
Tmp3 = DAG.getNode(ISD::MUL, dl, IdxVT, Tmp3,DAG.getConstant(EltSize, IdxVT));
SDValue StackPtr2 = DAG.getNode(ISD::ADD, dl, IdxVT, Tmp3, StackPtr);
// Store the scalar value.
Ch = DAG.getTruncStore(Ch, dl, Tmp2, StackPtr2, MachinePointerInfo(), EltVT,
false, false, 0);
// Load the updated vector.
return DAG.getLoad(VT, dl, Ch, StackPtr,
MachinePointerInfo::getFixedStack(SPFI), false, false,
false, 0);
}
SDValue SelectionDAGLegalize::
ExpandINSERT_VECTOR_ELT(SDValue Vec, SDValue Val, SDValue Idx, DebugLoc dl) {
if (ConstantSDNode *InsertPos = dyn_cast<ConstantSDNode>(Idx)) {
// SCALAR_TO_VECTOR requires that the type of the value being inserted
// match the element type of the vector being created, except for
// integers in which case the inserted value can be over width.
EVT EltVT = Vec.getValueType().getVectorElementType();
if (Val.getValueType() == EltVT ||
(EltVT.isInteger() && Val.getValueType().bitsGE(EltVT))) {
SDValue ScVec = DAG.getNode(ISD::SCALAR_TO_VECTOR, dl,
Vec.getValueType(), Val);
unsigned NumElts = Vec.getValueType().getVectorNumElements();
// We generate a shuffle of InVec and ScVec, so the shuffle mask
// should be 0,1,2,3,4,5... with the appropriate element replaced with
// elt 0 of the RHS.
SmallVector<int, 8> ShufOps;
for (unsigned i = 0; i != NumElts; ++i)
ShufOps.push_back(i != InsertPos->getZExtValue() ? i : NumElts);
return DAG.getVectorShuffle(Vec.getValueType(), dl, Vec, ScVec,
&ShufOps[0]);
}
}
return PerformInsertVectorEltInMemory(Vec, Val, Idx, dl);
}
SDValue SelectionDAGLegalize::OptimizeFloatStore(StoreSDNode* ST) {
// Turn 'store float 1.0, Ptr' -> 'store int 0x12345678, Ptr'
// FIXME: We shouldn't do this for TargetConstantFP's.
// FIXME: move this to the DAG Combiner! Note that we can't regress due
// to phase ordering between legalized code and the dag combiner. This
// probably means that we need to integrate dag combiner and legalizer
// together.
// We generally can't do this one for long doubles.
SDValue Chain = ST->getChain();
SDValue Ptr = ST->getBasePtr();
unsigned Alignment = ST->getAlignment();
bool isVolatile = ST->isVolatile();
bool isNonTemporal = ST->isNonTemporal();
DebugLoc dl = ST->getDebugLoc();
if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(ST->getValue())) {
if (CFP->getValueType(0) == MVT::f32 &&
TLI.isTypeLegal(MVT::i32)) {
SDValue Con = DAG.getConstant(CFP->getValueAPF().
bitcastToAPInt().zextOrTrunc(32),
MVT::i32);
return DAG.getStore(Chain, dl, Con, Ptr, ST->getPointerInfo(),
isVolatile, isNonTemporal, Alignment);
}
if (CFP->getValueType(0) == MVT::f64) {
// If this target supports 64-bit registers, do a single 64-bit store.
if (TLI.isTypeLegal(MVT::i64)) {
SDValue Con = DAG.getConstant(CFP->getValueAPF().bitcastToAPInt().
zextOrTrunc(64), MVT::i64);
return DAG.getStore(Chain, dl, Con, Ptr, ST->getPointerInfo(),
isVolatile, isNonTemporal, Alignment);
}
if (TLI.isTypeLegal(MVT::i32) && !ST->isVolatile()) {
// Otherwise, if the target supports 32-bit registers, use 2 32-bit
// stores. If the target supports neither 32- nor 64-bits, this
// xform is certainly not worth it.
const APInt &IntVal =CFP->getValueAPF().bitcastToAPInt();
SDValue Lo = DAG.getConstant(IntVal.trunc(32), MVT::i32);
SDValue Hi = DAG.getConstant(IntVal.lshr(32).trunc(32), MVT::i32);
if (TLI.isBigEndian()) std::swap(Lo, Hi);
Lo = DAG.getStore(Chain, dl, Lo, Ptr, ST->getPointerInfo(), isVolatile,
isNonTemporal, Alignment);
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getIntPtrConstant(4));
Hi = DAG.getStore(Chain, dl, Hi, Ptr,
ST->getPointerInfo().getWithOffset(4),
isVolatile, isNonTemporal, MinAlign(Alignment, 4U));
return DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo, Hi);
}
}
}
return SDValue(0, 0);
}
void SelectionDAGLegalize::LegalizeStoreOps(SDNode *Node) {
StoreSDNode *ST = cast<StoreSDNode>(Node);
SDValue Chain = ST->getChain();
SDValue Ptr = ST->getBasePtr();
DebugLoc dl = Node->getDebugLoc();
unsigned Alignment = ST->getAlignment();
bool isVolatile = ST->isVolatile();
bool isNonTemporal = ST->isNonTemporal();
if (!ST->isTruncatingStore()) {
if (SDNode *OptStore = OptimizeFloatStore(ST).getNode()) {
ReplaceNode(ST, OptStore);
return;
}
{
SDValue Value = ST->getValue();
MVT VT = Value.getSimpleValueType();
switch (TLI.getOperationAction(ISD::STORE, VT)) {
default: llvm_unreachable("This action is not supported yet!");
case TargetLowering::Legal:
// If this is an unaligned store and the target doesn't support it,
// expand it.
if (!TLI.allowsUnalignedMemoryAccesses(ST->getMemoryVT())) {
Type *Ty = ST->getMemoryVT().getTypeForEVT(*DAG.getContext());
unsigned ABIAlignment= TLI.getDataLayout()->getABITypeAlignment(Ty);
if (ST->getAlignment() < ABIAlignment)
ExpandUnalignedStore(cast<StoreSDNode>(Node),
DAG, TLI, this);
}
break;
case TargetLowering::Custom: {
SDValue Res = TLI.LowerOperation(SDValue(Node, 0), DAG);
if (Res.getNode())
ReplaceNode(SDValue(Node, 0), Res);
return;
}
case TargetLowering::Promote: {
MVT NVT = TLI.getTypeToPromoteTo(ISD::STORE, VT);
assert(NVT.getSizeInBits() == VT.getSizeInBits() &&
"Can only promote stores to same size type");
Value = DAG.getNode(ISD::BITCAST, dl, NVT, Value);
SDValue Result =
DAG.getStore(Chain, dl, Value, Ptr,
ST->getPointerInfo(), isVolatile,
isNonTemporal, Alignment);
ReplaceNode(SDValue(Node, 0), Result);
break;
}
}
return;
}
} else {
SDValue Value = ST->getValue();
EVT StVT = ST->getMemoryVT();
unsigned StWidth = StVT.getSizeInBits();
if (StWidth != StVT.getStoreSizeInBits()) {
// Promote to a byte-sized store with upper bits zero if not
// storing an integral number of bytes. For example, promote
// TRUNCSTORE:i1 X -> TRUNCSTORE:i8 (and X, 1)
EVT NVT = EVT::getIntegerVT(*DAG.getContext(),
StVT.getStoreSizeInBits());
Value = DAG.getZeroExtendInReg(Value, dl, StVT);
SDValue Result =
DAG.getTruncStore(Chain, dl, Value, Ptr, ST->getPointerInfo(),
NVT, isVolatile, isNonTemporal, Alignment);
ReplaceNode(SDValue(Node, 0), Result);
} else if (StWidth & (StWidth - 1)) {
// If not storing a power-of-2 number of bits, expand as two stores.
assert(!StVT.isVector() && "Unsupported truncstore!");
unsigned RoundWidth = 1 << Log2_32(StWidth);
assert(RoundWidth < StWidth);
unsigned ExtraWidth = StWidth - RoundWidth;
assert(ExtraWidth < RoundWidth);
assert(!(RoundWidth % 8) && !(ExtraWidth % 8) &&
"Store size not an integral number of bytes!");
EVT RoundVT = EVT::getIntegerVT(*DAG.getContext(), RoundWidth);
EVT ExtraVT = EVT::getIntegerVT(*DAG.getContext(), ExtraWidth);
SDValue Lo, Hi;
unsigned IncrementSize;
if (TLI.isLittleEndian()) {
// TRUNCSTORE:i24 X -> TRUNCSTORE:i16 X, TRUNCSTORE@+2:i8 (srl X, 16)
// Store the bottom RoundWidth bits.
Lo = DAG.getTruncStore(Chain, dl, Value, Ptr, ST->getPointerInfo(),
RoundVT,
isVolatile, isNonTemporal, Alignment);
// Store the remaining ExtraWidth bits.
IncrementSize = RoundWidth / 8;
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getIntPtrConstant(IncrementSize));
Hi = DAG.getNode(ISD::SRL, dl, Value.getValueType(), Value,
DAG.getConstant(RoundWidth,
TLI.getShiftAmountTy(Value.getValueType())));
Hi = DAG.getTruncStore(Chain, dl, Hi, Ptr,
ST->getPointerInfo().getWithOffset(IncrementSize),
ExtraVT, isVolatile, isNonTemporal,
MinAlign(Alignment, IncrementSize));
} else {
// Big endian - avoid unaligned stores.
// TRUNCSTORE:i24 X -> TRUNCSTORE:i16 (srl X, 8), TRUNCSTORE@+2:i8 X
// Store the top RoundWidth bits.
Hi = DAG.getNode(ISD::SRL, dl, Value.getValueType(), Value,
DAG.getConstant(ExtraWidth,
TLI.getShiftAmountTy(Value.getValueType())));
Hi = DAG.getTruncStore(Chain, dl, Hi, Ptr, ST->getPointerInfo(),
RoundVT, isVolatile, isNonTemporal, Alignment);
// Store the remaining ExtraWidth bits.
IncrementSize = RoundWidth / 8;
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getIntPtrConstant(IncrementSize));
Lo = DAG.getTruncStore(Chain, dl, Value, Ptr,
ST->getPointerInfo().getWithOffset(IncrementSize),
ExtraVT, isVolatile, isNonTemporal,
MinAlign(Alignment, IncrementSize));
}
// The order of the stores doesn't matter.
SDValue Result = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo, Hi);
ReplaceNode(SDValue(Node, 0), Result);
} else {
switch (TLI.getTruncStoreAction(ST->getValue().getSimpleValueType(),
StVT.getSimpleVT())) {
default: llvm_unreachable("This action is not supported yet!");
case TargetLowering::Legal:
// If this is an unaligned store and the target doesn't support it,
// expand it.
if (!TLI.allowsUnalignedMemoryAccesses(ST->getMemoryVT())) {
Type *Ty = ST->getMemoryVT().getTypeForEVT(*DAG.getContext());
unsigned ABIAlignment= TLI.getDataLayout()->getABITypeAlignment(Ty);
if (ST->getAlignment() < ABIAlignment)
ExpandUnalignedStore(cast<StoreSDNode>(Node), DAG, TLI, this);
}
break;
case TargetLowering::Custom: {
SDValue Res = TLI.LowerOperation(SDValue(Node, 0), DAG);
if (Res.getNode())
ReplaceNode(SDValue(Node, 0), Res);
return;
}
case TargetLowering::Expand:
assert(!StVT.isVector() &&
"Vector Stores are handled in LegalizeVectorOps");
// TRUNCSTORE:i16 i32 -> STORE i16
assert(TLI.isTypeLegal(StVT) &&
"Do not know how to expand this store!");
Value = DAG.getNode(ISD::TRUNCATE, dl, StVT, Value);
SDValue Result =
DAG.getStore(Chain, dl, Value, Ptr, ST->getPointerInfo(),
isVolatile, isNonTemporal, Alignment);
ReplaceNode(SDValue(Node, 0), Result);
break;
}
}
}
}
void SelectionDAGLegalize::LegalizeLoadOps(SDNode *Node) {
LoadSDNode *LD = cast<LoadSDNode>(Node);
SDValue Chain = LD->getChain(); // The chain.
SDValue Ptr = LD->getBasePtr(); // The base pointer.
SDValue Value; // The value returned by the load op.
DebugLoc dl = Node->getDebugLoc();
ISD::LoadExtType ExtType = LD->getExtensionType();
if (ExtType == ISD::NON_EXTLOAD) {
MVT VT = Node->getSimpleValueType(0);
SDValue RVal = SDValue(Node, 0);
SDValue RChain = SDValue(Node, 1);
switch (TLI.getOperationAction(Node->getOpcode(), VT)) {
default: llvm_unreachable("This action is not supported yet!");
case TargetLowering::Legal:
// If this is an unaligned load and the target doesn't support it,
// expand it.
if (!TLI.allowsUnalignedMemoryAccesses(LD->getMemoryVT())) {
Type *Ty = LD->getMemoryVT().getTypeForEVT(*DAG.getContext());
unsigned ABIAlignment =
TLI.getDataLayout()->getABITypeAlignment(Ty);
if (LD->getAlignment() < ABIAlignment){
ExpandUnalignedLoad(cast<LoadSDNode>(Node), DAG, TLI, RVal, RChain);
}
}
break;
case TargetLowering::Custom: {
SDValue Res = TLI.LowerOperation(RVal, DAG);
if (Res.getNode()) {
RVal = Res;
RChain = Res.getValue(1);
}
break;
}
case TargetLowering::Promote: {
MVT NVT = TLI.getTypeToPromoteTo(Node->getOpcode(), VT);
assert(NVT.getSizeInBits() == VT.getSizeInBits() &&
"Can only promote loads to same size type");
SDValue Res = DAG.getLoad(NVT, dl, Chain, Ptr, LD->getPointerInfo(),
LD->isVolatile(), LD->isNonTemporal(),
LD->isInvariant(), LD->getAlignment());
RVal = DAG.getNode(ISD::BITCAST, dl, VT, Res);
RChain = Res.getValue(1);
break;
}
}
if (RChain.getNode() != Node) {
assert(RVal.getNode() != Node && "Load must be completely replaced");
DAG.ReplaceAllUsesOfValueWith(SDValue(Node, 0), RVal);
DAG.ReplaceAllUsesOfValueWith(SDValue(Node, 1), RChain);
ReplacedNode(Node);
}
return;
}
EVT SrcVT = LD->getMemoryVT();
unsigned SrcWidth = SrcVT.getSizeInBits();
unsigned Alignment = LD->getAlignment();
bool isVolatile = LD->isVolatile();
bool isNonTemporal = LD->isNonTemporal();
if (SrcWidth != SrcVT.getStoreSizeInBits() &&
// Some targets pretend to have an i1 loading operation, and actually
// load an i8. This trick is correct for ZEXTLOAD because the top 7
// bits are guaranteed to be zero; it helps the optimizers understand
// that these bits are zero. It is also useful for EXTLOAD, since it
// tells the optimizers that those bits are undefined. It would be
// nice to have an effective generic way of getting these benefits...
// Until such a way is found, don't insist on promoting i1 here.
(SrcVT != MVT::i1 ||
TLI.getLoadExtAction(ExtType, MVT::i1) == TargetLowering::Promote)) {
// Promote to a byte-sized load if not loading an integral number of
// bytes. For example, promote EXTLOAD:i20 -> EXTLOAD:i24.
unsigned NewWidth = SrcVT.getStoreSizeInBits();
EVT NVT = EVT::getIntegerVT(*DAG.getContext(), NewWidth);
SDValue Ch;
// The extra bits are guaranteed to be zero, since we stored them that
// way. A zext load from NVT thus automatically gives zext from SrcVT.
ISD::LoadExtType NewExtType =
ExtType == ISD::ZEXTLOAD ? ISD::ZEXTLOAD : ISD::EXTLOAD;
SDValue Result =
DAG.getExtLoad(NewExtType, dl, Node->getValueType(0),
Chain, Ptr, LD->getPointerInfo(),
NVT, isVolatile, isNonTemporal, Alignment);
Ch = Result.getValue(1); // The chain.
if (ExtType == ISD::SEXTLOAD)
// Having the top bits zero doesn't help when sign extending.
Result = DAG.getNode(ISD::SIGN_EXTEND_INREG, dl,
Result.getValueType(),
Result, DAG.getValueType(SrcVT));
else if (ExtType == ISD::ZEXTLOAD || NVT == Result.getValueType())
// All the top bits are guaranteed to be zero - inform the optimizers.
Result = DAG.getNode(ISD::AssertZext, dl,
Result.getValueType(), Result,
DAG.getValueType(SrcVT));
Value = Result;
Chain = Ch;
} else if (SrcWidth & (SrcWidth - 1)) {
// If not loading a power-of-2 number of bits, expand as two loads.
assert(!SrcVT.isVector() && "Unsupported extload!");
unsigned RoundWidth = 1 << Log2_32(SrcWidth);
assert(RoundWidth < SrcWidth);
unsigned ExtraWidth = SrcWidth - RoundWidth;
assert(ExtraWidth < RoundWidth);
assert(!(RoundWidth % 8) && !(ExtraWidth % 8) &&
"Load size not an integral number of bytes!");
EVT RoundVT = EVT::getIntegerVT(*DAG.getContext(), RoundWidth);
EVT ExtraVT = EVT::getIntegerVT(*DAG.getContext(), ExtraWidth);
SDValue Lo, Hi, Ch;
unsigned IncrementSize;
if (TLI.isLittleEndian()) {
// EXTLOAD:i24 -> ZEXTLOAD:i16 | (shl EXTLOAD@+2:i8, 16)
// Load the bottom RoundWidth bits.
Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, Node->getValueType(0),
Chain, Ptr,
LD->getPointerInfo(), RoundVT, isVolatile,
isNonTemporal, Alignment);
// Load the remaining ExtraWidth bits.
IncrementSize = RoundWidth / 8;
Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
DAG.getIntPtrConstant(IncrementSize));
Hi = DAG.getExtLoad(ExtType, dl, Node->getValueType(0), Chain, Ptr,
LD->getPointerInfo().getWithOffset(IncrementSize),
ExtraVT, isVolatile, isNonTemporal,
MinAlign(Alignment, IncrementSize));
// Build a factor node to remember that this load is independent of
// the other one.
Ch = DAG.getNode(ISD::TokenFactor, dl, MVT::Other, Lo.getValue(1),
Hi.getValue(1));