1 //===-- LegalizeTypes.cpp - Common code for DAG type legalizer ------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements the SelectionDAG::LegalizeTypes method. It transforms
10 // an arbitrary well-formed SelectionDAG to only consist of legal types. This
11 // is common code shared among the LegalizeTypes*.cpp files.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "LegalizeTypes.h"
16 #include "SDNodeDbgValue.h"
17 #include "llvm/ADT/SetVector.h"
18 #include "llvm/CodeGen/MachineFunction.h"
19 #include "llvm/IR/CallingConv.h"
20 #include "llvm/IR/DataLayout.h"
21 #include "llvm/Support/CommandLine.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Support/raw_ostream.h"
24 using namespace llvm;
25
26 #define DEBUG_TYPE "legalize-types"
27
28 static cl::opt<bool>
29 EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden);
30
31 /// Do extensive, expensive, sanity checking.
PerformExpensiveChecks()32 void DAGTypeLegalizer::PerformExpensiveChecks() {
33 // If a node is not processed, then none of its values should be mapped by any
34 // of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
35
36 // If a node is processed, then each value with an illegal type must be mapped
37 // by exactly one of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
38 // Values with a legal type may be mapped by ReplacedValues, but not by any of
39 // the other maps.
40
41 // Note that these invariants may not hold momentarily when processing a node:
42 // the node being processed may be put in a map before being marked Processed.
43
44 // Note that it is possible to have nodes marked NewNode in the DAG. This can
45 // occur in two ways. Firstly, a node may be created during legalization but
46 // never passed to the legalization core. This is usually due to the implicit
47 // folding that occurs when using the DAG.getNode operators. Secondly, a new
48 // node may be passed to the legalization core, but when analyzed may morph
49 // into a different node, leaving the original node as a NewNode in the DAG.
50 // A node may morph if one of its operands changes during analysis. Whether
51 // it actually morphs or not depends on whether, after updating its operands,
52 // it is equivalent to an existing node: if so, it morphs into that existing
53 // node (CSE). An operand can change during analysis if the operand is a new
54 // node that morphs, or it is a processed value that was mapped to some other
55 // value (as recorded in ReplacedValues) in which case the operand is turned
56 // into that other value. If a node morphs then the node it morphed into will
57 // be used instead of it for legalization, however the original node continues
58 // to live on in the DAG.
59 // The conclusion is that though there may be nodes marked NewNode in the DAG,
60 // all uses of such nodes are also marked NewNode: the result is a fungus of
61 // NewNodes growing on top of the useful nodes, and perhaps using them, but
62 // not used by them.
63
64 // If a value is mapped by ReplacedValues, then it must have no uses, except
65 // by nodes marked NewNode (see above).
66
67 // The final node obtained by mapping by ReplacedValues is not marked NewNode.
68 // Note that ReplacedValues should be applied iteratively.
69
70 // Note that the ReplacedValues map may also map deleted nodes (by iterating
71 // over the DAG we never dereference deleted nodes). This means that it may
72 // also map nodes marked NewNode if the deallocated memory was reallocated as
73 // another node, and that new node was not seen by the LegalizeTypes machinery
74 // (for example because it was created but not used). In general, we cannot
75 // distinguish between new nodes and deleted nodes.
76 SmallVector<SDNode*, 16> NewNodes;
77 for (SDNode &Node : DAG.allnodes()) {
78 // Remember nodes marked NewNode - they are subject to extra checking below.
79 if (Node.getNodeId() == NewNode)
80 NewNodes.push_back(&Node);
81
82 for (unsigned i = 0, e = Node.getNumValues(); i != e; ++i) {
83 SDValue Res(&Node, i);
84 bool Failed = false;
85 // Don't create a value in map.
86 auto ResId = (ValueToIdMap.count(Res)) ? ValueToIdMap[Res] : 0;
87
88 unsigned Mapped = 0;
89 if (ResId && (ReplacedValues.find(ResId) != ReplacedValues.end())) {
90 Mapped |= 1;
91 // Check that remapped values are only used by nodes marked NewNode.
92 for (SDNode::use_iterator UI = Node.use_begin(), UE = Node.use_end();
93 UI != UE; ++UI)
94 if (UI.getUse().getResNo() == i)
95 assert(UI->getNodeId() == NewNode &&
96 "Remapped value has non-trivial use!");
97
98 // Check that the final result of applying ReplacedValues is not
99 // marked NewNode.
100 auto NewValId = ReplacedValues[ResId];
101 auto I = ReplacedValues.find(NewValId);
102 while (I != ReplacedValues.end()) {
103 NewValId = I->second;
104 I = ReplacedValues.find(NewValId);
105 }
106 SDValue NewVal = getSDValue(NewValId);
107 (void)NewVal;
108 assert(NewVal.getNode()->getNodeId() != NewNode &&
109 "ReplacedValues maps to a new node!");
110 }
111 if (ResId && PromotedIntegers.find(ResId) != PromotedIntegers.end())
112 Mapped |= 2;
113 if (ResId && SoftenedFloats.find(ResId) != SoftenedFloats.end())
114 Mapped |= 4;
115 if (ResId && ScalarizedVectors.find(ResId) != ScalarizedVectors.end())
116 Mapped |= 8;
117 if (ResId && ExpandedIntegers.find(ResId) != ExpandedIntegers.end())
118 Mapped |= 16;
119 if (ResId && ExpandedFloats.find(ResId) != ExpandedFloats.end())
120 Mapped |= 32;
121 if (ResId && SplitVectors.find(ResId) != SplitVectors.end())
122 Mapped |= 64;
123 if (ResId && WidenedVectors.find(ResId) != WidenedVectors.end())
124 Mapped |= 128;
125 if (ResId && PromotedFloats.find(ResId) != PromotedFloats.end())
126 Mapped |= 256;
127 if (ResId && SoftPromotedHalfs.find(ResId) != SoftPromotedHalfs.end())
128 Mapped |= 512;
129
130 if (Node.getNodeId() != Processed) {
131 // Since we allow ReplacedValues to map deleted nodes, it may map nodes
132 // marked NewNode too, since a deleted node may have been reallocated as
133 // another node that has not been seen by the LegalizeTypes machinery.
134 if ((Node.getNodeId() == NewNode && Mapped > 1) ||
135 (Node.getNodeId() != NewNode && Mapped != 0)) {
136 dbgs() << "Unprocessed value in a map!";
137 Failed = true;
138 }
139 } else if (isTypeLegal(Res.getValueType()) || IgnoreNodeResults(&Node)) {
140 if (Mapped > 1) {
141 dbgs() << "Value with legal type was transformed!";
142 Failed = true;
143 }
144 } else {
145 if (Mapped == 0) {
146 dbgs() << "Processed value not in any map!";
147 Failed = true;
148 } else if (Mapped & (Mapped - 1)) {
149 dbgs() << "Value in multiple maps!";
150 Failed = true;
151 }
152 }
153
154 if (Failed) {
155 if (Mapped & 1)
156 dbgs() << " ReplacedValues";
157 if (Mapped & 2)
158 dbgs() << " PromotedIntegers";
159 if (Mapped & 4)
160 dbgs() << " SoftenedFloats";
161 if (Mapped & 8)
162 dbgs() << " ScalarizedVectors";
163 if (Mapped & 16)
164 dbgs() << " ExpandedIntegers";
165 if (Mapped & 32)
166 dbgs() << " ExpandedFloats";
167 if (Mapped & 64)
168 dbgs() << " SplitVectors";
169 if (Mapped & 128)
170 dbgs() << " WidenedVectors";
171 if (Mapped & 256)
172 dbgs() << " PromotedFloats";
173 if (Mapped & 512)
174 dbgs() << " SoftPromoteHalfs";
175 dbgs() << "\n";
176 llvm_unreachable(nullptr);
177 }
178 }
179 }
180
181 #ifndef NDEBUG
182 // Checked that NewNodes are only used by other NewNodes.
183 for (unsigned i = 0, e = NewNodes.size(); i != e; ++i) {
184 SDNode *N = NewNodes[i];
185 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
186 UI != UE; ++UI)
187 assert(UI->getNodeId() == NewNode && "NewNode used by non-NewNode!");
188 }
189 #endif
190 }
191
192 /// This is the main entry point for the type legalizer. This does a top-down
193 /// traversal of the dag, legalizing types as it goes. Returns "true" if it made
194 /// any changes.
run()195 bool DAGTypeLegalizer::run() {
196 bool Changed = false;
197
198 // Create a dummy node (which is not added to allnodes), that adds a reference
199 // to the root node, preventing it from being deleted, and tracking any
200 // changes of the root.
201 HandleSDNode Dummy(DAG.getRoot());
202 Dummy.setNodeId(Unanalyzed);
203
204 // The root of the dag may dangle to deleted nodes until the type legalizer is
205 // done. Set it to null to avoid confusion.
206 DAG.setRoot(SDValue());
207
208 // Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess'
209 // (and remembering them) if they are leaves and assigning 'Unanalyzed' if
210 // non-leaves.
211 for (SDNode &Node : DAG.allnodes()) {
212 if (Node.getNumOperands() == 0) {
213 Node.setNodeId(ReadyToProcess);
214 Worklist.push_back(&Node);
215 } else {
216 Node.setNodeId(Unanalyzed);
217 }
218 }
219
220 // Now that we have a set of nodes to process, handle them all.
221 while (!Worklist.empty()) {
222 #ifndef EXPENSIVE_CHECKS
223 if (EnableExpensiveChecks)
224 #endif
225 PerformExpensiveChecks();
226
227 SDNode *N = Worklist.back();
228 Worklist.pop_back();
229 assert(N->getNodeId() == ReadyToProcess &&
230 "Node should be ready if on worklist!");
231
232 LLVM_DEBUG(dbgs() << "Legalizing node: "; N->dump(&DAG));
233 if (IgnoreNodeResults(N)) {
234 LLVM_DEBUG(dbgs() << "Ignoring node results\n");
235 goto ScanOperands;
236 }
237
238 // Scan the values produced by the node, checking to see if any result
239 // types are illegal.
240 for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) {
241 EVT ResultVT = N->getValueType(i);
242 LLVM_DEBUG(dbgs() << "Analyzing result type: " << ResultVT.getEVTString()
243 << "\n");
244 switch (getTypeAction(ResultVT)) {
245 case TargetLowering::TypeLegal:
246 LLVM_DEBUG(dbgs() << "Legal result type\n");
247 break;
248 case TargetLowering::TypeScalarizeScalableVector:
249 report_fatal_error(
250 "Scalarization of scalable vectors is not supported.");
251 // The following calls must take care of *all* of the node's results,
252 // not just the illegal result they were passed (this includes results
253 // with a legal type). Results can be remapped using ReplaceValueWith,
254 // or their promoted/expanded/etc values registered in PromotedIntegers,
255 // ExpandedIntegers etc.
256 case TargetLowering::TypePromoteInteger:
257 PromoteIntegerResult(N, i);
258 Changed = true;
259 goto NodeDone;
260 case TargetLowering::TypeExpandInteger:
261 ExpandIntegerResult(N, i);
262 Changed = true;
263 goto NodeDone;
264 case TargetLowering::TypeSoftenFloat:
265 SoftenFloatResult(N, i);
266 Changed = true;
267 goto NodeDone;
268 case TargetLowering::TypeExpandFloat:
269 ExpandFloatResult(N, i);
270 Changed = true;
271 goto NodeDone;
272 case TargetLowering::TypeScalarizeVector:
273 ScalarizeVectorResult(N, i);
274 Changed = true;
275 goto NodeDone;
276 case TargetLowering::TypeSplitVector:
277 SplitVectorResult(N, i);
278 Changed = true;
279 goto NodeDone;
280 case TargetLowering::TypeWidenVector:
281 WidenVectorResult(N, i);
282 Changed = true;
283 goto NodeDone;
284 case TargetLowering::TypePromoteFloat:
285 PromoteFloatResult(N, i);
286 Changed = true;
287 goto NodeDone;
288 case TargetLowering::TypeSoftPromoteHalf:
289 SoftPromoteHalfResult(N, i);
290 Changed = true;
291 goto NodeDone;
292 }
293 }
294
295 ScanOperands:
296 // Scan the operand list for the node, handling any nodes with operands that
297 // are illegal.
298 {
299 unsigned NumOperands = N->getNumOperands();
300 bool NeedsReanalyzing = false;
301 unsigned i;
302 for (i = 0; i != NumOperands; ++i) {
303 if (IgnoreNodeResults(N->getOperand(i).getNode()))
304 continue;
305
306 const auto Op = N->getOperand(i);
307 LLVM_DEBUG(dbgs() << "Analyzing operand: "; Op.dump(&DAG));
308 EVT OpVT = Op.getValueType();
309 switch (getTypeAction(OpVT)) {
310 case TargetLowering::TypeLegal:
311 LLVM_DEBUG(dbgs() << "Legal operand\n");
312 continue;
313 case TargetLowering::TypeScalarizeScalableVector:
314 report_fatal_error(
315 "Scalarization of scalable vectors is not supported.");
316 // The following calls must either replace all of the node's results
317 // using ReplaceValueWith, and return "false"; or update the node's
318 // operands in place, and return "true".
319 case TargetLowering::TypePromoteInteger:
320 NeedsReanalyzing = PromoteIntegerOperand(N, i);
321 Changed = true;
322 break;
323 case TargetLowering::TypeExpandInteger:
324 NeedsReanalyzing = ExpandIntegerOperand(N, i);
325 Changed = true;
326 break;
327 case TargetLowering::TypeSoftenFloat:
328 NeedsReanalyzing = SoftenFloatOperand(N, i);
329 Changed = true;
330 break;
331 case TargetLowering::TypeExpandFloat:
332 NeedsReanalyzing = ExpandFloatOperand(N, i);
333 Changed = true;
334 break;
335 case TargetLowering::TypeScalarizeVector:
336 NeedsReanalyzing = ScalarizeVectorOperand(N, i);
337 Changed = true;
338 break;
339 case TargetLowering::TypeSplitVector:
340 NeedsReanalyzing = SplitVectorOperand(N, i);
341 Changed = true;
342 break;
343 case TargetLowering::TypeWidenVector:
344 NeedsReanalyzing = WidenVectorOperand(N, i);
345 Changed = true;
346 break;
347 case TargetLowering::TypePromoteFloat:
348 NeedsReanalyzing = PromoteFloatOperand(N, i);
349 Changed = true;
350 break;
351 case TargetLowering::TypeSoftPromoteHalf:
352 NeedsReanalyzing = SoftPromoteHalfOperand(N, i);
353 Changed = true;
354 break;
355 }
356 break;
357 }
358
359 // The sub-method updated N in place. Check to see if any operands are new,
360 // and if so, mark them. If the node needs revisiting, don't add all users
361 // to the worklist etc.
362 if (NeedsReanalyzing) {
363 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
364
365 N->setNodeId(NewNode);
366 // Recompute the NodeId and correct processed operands, adding the node to
367 // the worklist if ready.
368 SDNode *M = AnalyzeNewNode(N);
369 if (M == N)
370 // The node didn't morph - nothing special to do, it will be revisited.
371 continue;
372
373 // The node morphed - this is equivalent to legalizing by replacing every
374 // value of N with the corresponding value of M. So do that now.
375 assert(N->getNumValues() == M->getNumValues() &&
376 "Node morphing changed the number of results!");
377 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
378 // Replacing the value takes care of remapping the new value.
379 ReplaceValueWith(SDValue(N, i), SDValue(M, i));
380 assert(N->getNodeId() == NewNode && "Unexpected node state!");
381 // The node continues to live on as part of the NewNode fungus that
382 // grows on top of the useful nodes. Nothing more needs to be done
383 // with it - move on to the next node.
384 continue;
385 }
386
387 if (i == NumOperands) {
388 LLVM_DEBUG(dbgs() << "Legally typed node: "; N->dump(&DAG);
389 dbgs() << "\n");
390 }
391 }
392 NodeDone:
393
394 // If we reach here, the node was processed, potentially creating new nodes.
395 // Mark it as processed and add its users to the worklist as appropriate.
396 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
397 N->setNodeId(Processed);
398
399 for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end();
400 UI != E; ++UI) {
401 SDNode *User = *UI;
402 int NodeId = User->getNodeId();
403
404 // This node has two options: it can either be a new node or its Node ID
405 // may be a count of the number of operands it has that are not ready.
406 if (NodeId > 0) {
407 User->setNodeId(NodeId-1);
408
409 // If this was the last use it was waiting on, add it to the ready list.
410 if (NodeId-1 == ReadyToProcess)
411 Worklist.push_back(User);
412 continue;
413 }
414
415 // If this is an unreachable new node, then ignore it. If it ever becomes
416 // reachable by being used by a newly created node then it will be handled
417 // by AnalyzeNewNode.
418 if (NodeId == NewNode)
419 continue;
420
421 // Otherwise, this node is new: this is the first operand of it that
422 // became ready. Its new NodeId is the number of operands it has minus 1
423 // (as this node is now processed).
424 assert(NodeId == Unanalyzed && "Unknown node ID!");
425 User->setNodeId(User->getNumOperands() - 1);
426
427 // If the node only has a single operand, it is now ready.
428 if (User->getNumOperands() == 1)
429 Worklist.push_back(User);
430 }
431 }
432
433 #ifndef EXPENSIVE_CHECKS
434 if (EnableExpensiveChecks)
435 #endif
436 PerformExpensiveChecks();
437
438 // If the root changed (e.g. it was a dead load) update the root.
439 DAG.setRoot(Dummy.getValue());
440
441 // Remove dead nodes. This is important to do for cleanliness but also before
442 // the checking loop below. Implicit folding by the DAG.getNode operators and
443 // node morphing can cause unreachable nodes to be around with their flags set
444 // to new.
445 DAG.RemoveDeadNodes();
446
447 // In a debug build, scan all the nodes to make sure we found them all. This
448 // ensures that there are no cycles and that everything got processed.
449 #ifndef NDEBUG
450 for (SDNode &Node : DAG.allnodes()) {
451 bool Failed = false;
452
453 // Check that all result types are legal.
454 if (!IgnoreNodeResults(&Node))
455 for (unsigned i = 0, NumVals = Node.getNumValues(); i < NumVals; ++i)
456 if (!isTypeLegal(Node.getValueType(i))) {
457 dbgs() << "Result type " << i << " illegal: ";
458 Node.dump(&DAG);
459 Failed = true;
460 }
461
462 // Check that all operand types are legal.
463 for (unsigned i = 0, NumOps = Node.getNumOperands(); i < NumOps; ++i)
464 if (!IgnoreNodeResults(Node.getOperand(i).getNode()) &&
465 !isTypeLegal(Node.getOperand(i).getValueType())) {
466 dbgs() << "Operand type " << i << " illegal: ";
467 Node.getOperand(i).dump(&DAG);
468 Failed = true;
469 }
470
471 if (Node.getNodeId() != Processed) {
472 if (Node.getNodeId() == NewNode)
473 dbgs() << "New node not analyzed?\n";
474 else if (Node.getNodeId() == Unanalyzed)
475 dbgs() << "Unanalyzed node not noticed?\n";
476 else if (Node.getNodeId() > 0)
477 dbgs() << "Operand not processed?\n";
478 else if (Node.getNodeId() == ReadyToProcess)
479 dbgs() << "Not added to worklist?\n";
480 Failed = true;
481 }
482
483 if (Failed) {
484 Node.dump(&DAG); dbgs() << "\n";
485 llvm_unreachable(nullptr);
486 }
487 }
488 #endif
489
490 return Changed;
491 }
492
493 /// The specified node is the root of a subtree of potentially new nodes.
494 /// Correct any processed operands (this may change the node) and calculate the
495 /// NodeId. If the node itself changes to a processed node, it is not remapped -
496 /// the caller needs to take care of this. Returns the potentially changed node.
AnalyzeNewNode(SDNode * N)497 SDNode *DAGTypeLegalizer::AnalyzeNewNode(SDNode *N) {
498 // If this was an existing node that is already done, we're done.
499 if (N->getNodeId() != NewNode && N->getNodeId() != Unanalyzed)
500 return N;
501
502 // Okay, we know that this node is new. Recursively walk all of its operands
503 // to see if they are new also. The depth of this walk is bounded by the size
504 // of the new tree that was constructed (usually 2-3 nodes), so we don't worry
505 // about revisiting of nodes.
506 //
507 // As we walk the operands, keep track of the number of nodes that are
508 // processed. If non-zero, this will become the new nodeid of this node.
509 // Operands may morph when they are analyzed. If so, the node will be
510 // updated after all operands have been analyzed. Since this is rare,
511 // the code tries to minimize overhead in the non-morphing case.
512
513 std::vector<SDValue> NewOps;
514 unsigned NumProcessed = 0;
515 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
516 SDValue OrigOp = N->getOperand(i);
517 SDValue Op = OrigOp;
518
519 AnalyzeNewValue(Op); // Op may morph.
520
521 if (Op.getNode()->getNodeId() == Processed)
522 ++NumProcessed;
523
524 if (!NewOps.empty()) {
525 // Some previous operand changed. Add this one to the list.
526 NewOps.push_back(Op);
527 } else if (Op != OrigOp) {
528 // This is the first operand to change - add all operands so far.
529 NewOps.insert(NewOps.end(), N->op_begin(), N->op_begin() + i);
530 NewOps.push_back(Op);
531 }
532 }
533
534 // Some operands changed - update the node.
535 if (!NewOps.empty()) {
536 SDNode *M = DAG.UpdateNodeOperands(N, NewOps);
537 if (M != N) {
538 // The node morphed into a different node. Normally for this to happen
539 // the original node would have to be marked NewNode. However this can
540 // in theory momentarily not be the case while ReplaceValueWith is doing
541 // its stuff. Mark the original node NewNode to help sanity checking.
542 N->setNodeId(NewNode);
543 if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed)
544 // It morphed into a previously analyzed node - nothing more to do.
545 return M;
546
547 // It morphed into a different new node. Do the equivalent of passing
548 // it to AnalyzeNewNode: expunge it and calculate the NodeId. No need
549 // to remap the operands, since they are the same as the operands we
550 // remapped above.
551 N = M;
552 }
553 }
554
555 // Calculate the NodeId.
556 N->setNodeId(N->getNumOperands() - NumProcessed);
557 if (N->getNodeId() == ReadyToProcess)
558 Worklist.push_back(N);
559
560 return N;
561 }
562
563 /// Call AnalyzeNewNode, updating the node in Val if needed.
564 /// If the node changes to a processed node, then remap it.
AnalyzeNewValue(SDValue & Val)565 void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) {
566 Val.setNode(AnalyzeNewNode(Val.getNode()));
567 if (Val.getNode()->getNodeId() == Processed)
568 // We were passed a processed node, or it morphed into one - remap it.
569 RemapValue(Val);
570 }
571
572 /// If the specified value was already legalized to another value,
573 /// replace it by that value.
RemapValue(SDValue & V)574 void DAGTypeLegalizer::RemapValue(SDValue &V) {
575 auto Id = getTableId(V);
576 V = getSDValue(Id);
577 }
578
RemapId(TableId & Id)579 void DAGTypeLegalizer::RemapId(TableId &Id) {
580 auto I = ReplacedValues.find(Id);
581 if (I != ReplacedValues.end()) {
582 assert(Id != I->second && "Id is mapped to itself.");
583 // Use path compression to speed up future lookups if values get multiply
584 // replaced with other values.
585 RemapId(I->second);
586 Id = I->second;
587
588 // Note that N = IdToValueMap[Id] it is possible to have
589 // N.getNode()->getNodeId() == NewNode at this point because it is possible
590 // for a node to be put in the map before being processed.
591 }
592 }
593
594 namespace {
595 /// This class is a DAGUpdateListener that listens for updates to nodes and
596 /// recomputes their ready state.
597 class NodeUpdateListener : public SelectionDAG::DAGUpdateListener {
598 DAGTypeLegalizer &DTL;
599 SmallSetVector<SDNode*, 16> &NodesToAnalyze;
600 public:
NodeUpdateListener(DAGTypeLegalizer & dtl,SmallSetVector<SDNode *,16> & nta)601 explicit NodeUpdateListener(DAGTypeLegalizer &dtl,
602 SmallSetVector<SDNode*, 16> &nta)
603 : SelectionDAG::DAGUpdateListener(dtl.getDAG()),
604 DTL(dtl), NodesToAnalyze(nta) {}
605
NodeDeleted(SDNode * N,SDNode * E)606 void NodeDeleted(SDNode *N, SDNode *E) override {
607 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
608 N->getNodeId() != DAGTypeLegalizer::Processed &&
609 "Invalid node ID for RAUW deletion!");
610 // It is possible, though rare, for the deleted node N to occur as a
611 // target in a map, so note the replacement N -> E in ReplacedValues.
612 assert(E && "Node not replaced?");
613 DTL.NoteDeletion(N, E);
614
615 // In theory the deleted node could also have been scheduled for analysis.
616 // So remove it from the set of nodes which will be analyzed.
617 NodesToAnalyze.remove(N);
618
619 // In general nothing needs to be done for E, since it didn't change but
620 // only gained new uses. However N -> E was just added to ReplacedValues,
621 // and the result of a ReplacedValues mapping is not allowed to be marked
622 // NewNode. So if E is marked NewNode, then it needs to be analyzed.
623 if (E->getNodeId() == DAGTypeLegalizer::NewNode)
624 NodesToAnalyze.insert(E);
625 }
626
NodeUpdated(SDNode * N)627 void NodeUpdated(SDNode *N) override {
628 // Node updates can mean pretty much anything. It is possible that an
629 // operand was set to something already processed (f.e.) in which case
630 // this node could become ready. Recompute its flags.
631 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
632 N->getNodeId() != DAGTypeLegalizer::Processed &&
633 "Invalid node ID for RAUW deletion!");
634 N->setNodeId(DAGTypeLegalizer::NewNode);
635 NodesToAnalyze.insert(N);
636 }
637 };
638 }
639
640
641 /// The specified value was legalized to the specified other value.
642 /// Update the DAG and NodeIds replacing any uses of From to use To instead.
ReplaceValueWith(SDValue From,SDValue To)643 void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) {
644 assert(From.getNode() != To.getNode() && "Potential legalization loop!");
645
646 // If expansion produced new nodes, make sure they are properly marked.
647 AnalyzeNewValue(To);
648
649 // Anything that used the old node should now use the new one. Note that this
650 // can potentially cause recursive merging.
651 SmallSetVector<SDNode*, 16> NodesToAnalyze;
652 NodeUpdateListener NUL(*this, NodesToAnalyze);
653 do {
654
655 // The old node may be present in a map like ExpandedIntegers or
656 // PromotedIntegers. Inform maps about the replacement.
657 auto FromId = getTableId(From);
658 auto ToId = getTableId(To);
659
660 if (FromId != ToId)
661 ReplacedValues[FromId] = ToId;
662 DAG.ReplaceAllUsesOfValueWith(From, To);
663
664 // Process the list of nodes that need to be reanalyzed.
665 while (!NodesToAnalyze.empty()) {
666 SDNode *N = NodesToAnalyze.back();
667 NodesToAnalyze.pop_back();
668 if (N->getNodeId() != DAGTypeLegalizer::NewNode)
669 // The node was analyzed while reanalyzing an earlier node - it is safe
670 // to skip. Note that this is not a morphing node - otherwise it would
671 // still be marked NewNode.
672 continue;
673
674 // Analyze the node's operands and recalculate the node ID.
675 SDNode *M = AnalyzeNewNode(N);
676 if (M != N) {
677 // The node morphed into a different node. Make everyone use the new
678 // node instead.
679 assert(M->getNodeId() != NewNode && "Analysis resulted in NewNode!");
680 assert(N->getNumValues() == M->getNumValues() &&
681 "Node morphing changed the number of results!");
682 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) {
683 SDValue OldVal(N, i);
684 SDValue NewVal(M, i);
685 if (M->getNodeId() == Processed)
686 RemapValue(NewVal);
687 // OldVal may be a target of the ReplacedValues map which was marked
688 // NewNode to force reanalysis because it was updated. Ensure that
689 // anything that ReplacedValues mapped to OldVal will now be mapped
690 // all the way to NewVal.
691 auto OldValId = getTableId(OldVal);
692 auto NewValId = getTableId(NewVal);
693 DAG.ReplaceAllUsesOfValueWith(OldVal, NewVal);
694 if (OldValId != NewValId)
695 ReplacedValues[OldValId] = NewValId;
696 }
697 // The original node continues to exist in the DAG, marked NewNode.
698 }
699 }
700 // When recursively update nodes with new nodes, it is possible to have
701 // new uses of From due to CSE. If this happens, replace the new uses of
702 // From with To.
703 } while (!From.use_empty());
704 }
705
SetPromotedInteger(SDValue Op,SDValue Result)706 void DAGTypeLegalizer::SetPromotedInteger(SDValue Op, SDValue Result) {
707 assert(Result.getValueType() ==
708 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
709 "Invalid type for promoted integer");
710 AnalyzeNewValue(Result);
711
712 auto &OpIdEntry = PromotedIntegers[getTableId(Op)];
713 assert((OpIdEntry == 0) && "Node is already promoted!");
714 OpIdEntry = getTableId(Result);
715 Result->setFlags(Op->getFlags());
716
717 DAG.transferDbgValues(Op, Result);
718 }
719
SetSoftenedFloat(SDValue Op,SDValue Result)720 void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) {
721 assert(Result.getValueType() ==
722 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
723 "Invalid type for softened float");
724 AnalyzeNewValue(Result);
725
726 auto &OpIdEntry = SoftenedFloats[getTableId(Op)];
727 assert((OpIdEntry == 0) && "Node is already converted to integer!");
728 OpIdEntry = getTableId(Result);
729 }
730
SetPromotedFloat(SDValue Op,SDValue Result)731 void DAGTypeLegalizer::SetPromotedFloat(SDValue Op, SDValue Result) {
732 assert(Result.getValueType() ==
733 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
734 "Invalid type for promoted float");
735 AnalyzeNewValue(Result);
736
737 auto &OpIdEntry = PromotedFloats[getTableId(Op)];
738 assert((OpIdEntry == 0) && "Node is already promoted!");
739 OpIdEntry = getTableId(Result);
740 }
741
SetSoftPromotedHalf(SDValue Op,SDValue Result)742 void DAGTypeLegalizer::SetSoftPromotedHalf(SDValue Op, SDValue Result) {
743 assert(Result.getValueType() == MVT::i16 &&
744 "Invalid type for soft-promoted half");
745 AnalyzeNewValue(Result);
746
747 auto &OpIdEntry = SoftPromotedHalfs[getTableId(Op)];
748 assert((OpIdEntry == 0) && "Node is already promoted!");
749 OpIdEntry = getTableId(Result);
750 }
751
SetScalarizedVector(SDValue Op,SDValue Result)752 void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) {
753 // Note that in some cases vector operation operands may be greater than
754 // the vector element type. For example BUILD_VECTOR of type <1 x i1> with
755 // a constant i8 operand.
756 assert(Result.getValueSizeInBits() >= Op.getScalarValueSizeInBits() &&
757 "Invalid type for scalarized vector");
758 AnalyzeNewValue(Result);
759
760 auto &OpIdEntry = ScalarizedVectors[getTableId(Op)];
761 assert((OpIdEntry == 0) && "Node is already scalarized!");
762 OpIdEntry = getTableId(Result);
763 }
764
GetExpandedInteger(SDValue Op,SDValue & Lo,SDValue & Hi)765 void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo,
766 SDValue &Hi) {
767 std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(Op)];
768 assert((Entry.first != 0) && "Operand isn't expanded");
769 Lo = getSDValue(Entry.first);
770 Hi = getSDValue(Entry.second);
771 }
772
SetExpandedInteger(SDValue Op,SDValue Lo,SDValue Hi)773 void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo,
774 SDValue Hi) {
775 assert(Lo.getValueType() ==
776 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
777 Hi.getValueType() == Lo.getValueType() &&
778 "Invalid type for expanded integer");
779 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
780 AnalyzeNewValue(Lo);
781 AnalyzeNewValue(Hi);
782
783 // Transfer debug values. Don't invalidate the source debug value until it's
784 // been transferred to the high and low bits.
785 if (DAG.getDataLayout().isBigEndian()) {
786 DAG.transferDbgValues(Op, Hi, 0, Hi.getValueSizeInBits(), false);
787 DAG.transferDbgValues(Op, Lo, Hi.getValueSizeInBits(),
788 Lo.getValueSizeInBits());
789 } else {
790 DAG.transferDbgValues(Op, Lo, 0, Lo.getValueSizeInBits(), false);
791 DAG.transferDbgValues(Op, Hi, Lo.getValueSizeInBits(),
792 Hi.getValueSizeInBits());
793 }
794
795 // Remember that this is the result of the node.
796 std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(Op)];
797 assert((Entry.first == 0) && "Node already expanded");
798 Entry.first = getTableId(Lo);
799 Entry.second = getTableId(Hi);
800 }
801
GetExpandedFloat(SDValue Op,SDValue & Lo,SDValue & Hi)802 void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo,
803 SDValue &Hi) {
804 std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(Op)];
805 assert((Entry.first != 0) && "Operand isn't expanded");
806 Lo = getSDValue(Entry.first);
807 Hi = getSDValue(Entry.second);
808 }
809
SetExpandedFloat(SDValue Op,SDValue Lo,SDValue Hi)810 void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo,
811 SDValue Hi) {
812 assert(Lo.getValueType() ==
813 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
814 Hi.getValueType() == Lo.getValueType() &&
815 "Invalid type for expanded float");
816 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
817 AnalyzeNewValue(Lo);
818 AnalyzeNewValue(Hi);
819
820 std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(Op)];
821 assert((Entry.first == 0) && "Node already expanded");
822 Entry.first = getTableId(Lo);
823 Entry.second = getTableId(Hi);
824 }
825
GetSplitVector(SDValue Op,SDValue & Lo,SDValue & Hi)826 void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo,
827 SDValue &Hi) {
828 std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)];
829 Lo = getSDValue(Entry.first);
830 Hi = getSDValue(Entry.second);
831 assert(Lo.getNode() && "Operand isn't split");
832 ;
833 }
834
SetSplitVector(SDValue Op,SDValue Lo,SDValue Hi)835 void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo,
836 SDValue Hi) {
837 assert(Lo.getValueType().getVectorElementType() ==
838 Op.getValueType().getVectorElementType() &&
839 Lo.getValueType().getVectorElementCount() * 2 ==
840 Op.getValueType().getVectorElementCount() &&
841 Hi.getValueType() == Lo.getValueType() &&
842 "Invalid type for split vector");
843 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
844 AnalyzeNewValue(Lo);
845 AnalyzeNewValue(Hi);
846
847 // Remember that this is the result of the node.
848 std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)];
849 assert((Entry.first == 0) && "Node already split");
850 Entry.first = getTableId(Lo);
851 Entry.second = getTableId(Hi);
852 }
853
SetWidenedVector(SDValue Op,SDValue Result)854 void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) {
855 assert(Result.getValueType() ==
856 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
857 "Invalid type for widened vector");
858 AnalyzeNewValue(Result);
859
860 auto &OpIdEntry = WidenedVectors[getTableId(Op)];
861 assert((OpIdEntry == 0) && "Node already widened!");
862 OpIdEntry = getTableId(Result);
863 }
864
865
866 //===----------------------------------------------------------------------===//
867 // Utilities.
868 //===----------------------------------------------------------------------===//
869
870 /// Convert to an integer of the same size.
BitConvertToInteger(SDValue Op)871 SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) {
872 unsigned BitWidth = Op.getValueSizeInBits();
873 return DAG.getNode(ISD::BITCAST, SDLoc(Op),
874 EVT::getIntegerVT(*DAG.getContext(), BitWidth), Op);
875 }
876
877 /// Convert to a vector of integers of the same size.
BitConvertVectorToIntegerVector(SDValue Op)878 SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) {
879 assert(Op.getValueType().isVector() && "Only applies to vectors!");
880 unsigned EltWidth = Op.getScalarValueSizeInBits();
881 EVT EltNVT = EVT::getIntegerVT(*DAG.getContext(), EltWidth);
882 auto EltCnt = Op.getValueType().getVectorElementCount();
883 return DAG.getNode(ISD::BITCAST, SDLoc(Op),
884 EVT::getVectorVT(*DAG.getContext(), EltNVT, EltCnt), Op);
885 }
886
CreateStackStoreLoad(SDValue Op,EVT DestVT)887 SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op,
888 EVT DestVT) {
889 SDLoc dl(Op);
890 // Create the stack frame object. Make sure it is aligned for both
891 // the source and destination types.
892
893 // In cases where the vector is illegal it will be broken down into parts
894 // and stored in parts - we should use the alignment for the smallest part.
895 Align DestAlign = DAG.getReducedAlign(DestVT, /*UseABI=*/false);
896 Align OpAlign = DAG.getReducedAlign(Op.getValueType(), /*UseABI=*/false);
897 Align Align = std::max(DestAlign, OpAlign);
898 SDValue StackPtr =
899 DAG.CreateStackTemporary(Op.getValueType().getStoreSize(), Align);
900 // Emit a store to the stack slot.
901 SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Op, StackPtr,
902 MachinePointerInfo(), Align);
903 // Result is a load from the stack slot.
904 return DAG.getLoad(DestVT, dl, Store, StackPtr, MachinePointerInfo(), Align);
905 }
906
907 /// Replace the node's results with custom code provided by the target and
908 /// return "true", or do nothing and return "false".
909 /// The last parameter is FALSE if we are dealing with a node with legal
910 /// result types and illegal operand. The second parameter denotes the type of
911 /// illegal OperandNo in that case.
912 /// The last parameter being TRUE means we are dealing with a
913 /// node with illegal result types. The second parameter denotes the type of
914 /// illegal ResNo in that case.
CustomLowerNode(SDNode * N,EVT VT,bool LegalizeResult)915 bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) {
916 // See if the target wants to custom lower this node.
917 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom)
918 return false;
919
920 SmallVector<SDValue, 8> Results;
921 if (LegalizeResult)
922 TLI.ReplaceNodeResults(N, Results, DAG);
923 else
924 TLI.LowerOperationWrapper(N, Results, DAG);
925
926 if (Results.empty())
927 // The target didn't want to custom lower it after all.
928 return false;
929
930 // Make everything that once used N's values now use those in Results instead.
931 assert(Results.size() == N->getNumValues() &&
932 "Custom lowering returned the wrong number of results!");
933 for (unsigned i = 0, e = Results.size(); i != e; ++i) {
934 ReplaceValueWith(SDValue(N, i), Results[i]);
935 }
936 return true;
937 }
938
939
940 /// Widen the node's results with custom code provided by the target and return
941 /// "true", or do nothing and return "false".
CustomWidenLowerNode(SDNode * N,EVT VT)942 bool DAGTypeLegalizer::CustomWidenLowerNode(SDNode *N, EVT VT) {
943 // See if the target wants to custom lower this node.
944 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom)
945 return false;
946
947 SmallVector<SDValue, 8> Results;
948 TLI.ReplaceNodeResults(N, Results, DAG);
949
950 if (Results.empty())
951 // The target didn't want to custom widen lower its result after all.
952 return false;
953
954 // Update the widening map.
955 assert(Results.size() == N->getNumValues() &&
956 "Custom lowering returned the wrong number of results!");
957 for (unsigned i = 0, e = Results.size(); i != e; ++i) {
958 // If this is a chain output just replace it.
959 if (Results[i].getValueType() == MVT::Other)
960 ReplaceValueWith(SDValue(N, i), Results[i]);
961 else
962 SetWidenedVector(SDValue(N, i), Results[i]);
963 }
964 return true;
965 }
966
DisintegrateMERGE_VALUES(SDNode * N,unsigned ResNo)967 SDValue DAGTypeLegalizer::DisintegrateMERGE_VALUES(SDNode *N, unsigned ResNo) {
968 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
969 if (i != ResNo)
970 ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
971 return SDValue(N->getOperand(ResNo));
972 }
973
974 /// Use ISD::EXTRACT_ELEMENT nodes to extract the low and high parts of the
975 /// given value.
GetPairElements(SDValue Pair,SDValue & Lo,SDValue & Hi)976 void DAGTypeLegalizer::GetPairElements(SDValue Pair,
977 SDValue &Lo, SDValue &Hi) {
978 SDLoc dl(Pair);
979 EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), Pair.getValueType());
980 Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair,
981 DAG.getIntPtrConstant(0, dl));
982 Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair,
983 DAG.getIntPtrConstant(1, dl));
984 }
985
986 /// Build an integer with low bits Lo and high bits Hi.
JoinIntegers(SDValue Lo,SDValue Hi)987 SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) {
988 // Arbitrarily use dlHi for result SDLoc
989 SDLoc dlHi(Hi);
990 SDLoc dlLo(Lo);
991 EVT LVT = Lo.getValueType();
992 EVT HVT = Hi.getValueType();
993 EVT NVT = EVT::getIntegerVT(*DAG.getContext(),
994 LVT.getSizeInBits() + HVT.getSizeInBits());
995
996 EVT ShiftAmtVT = TLI.getShiftAmountTy(NVT, DAG.getDataLayout(), false);
997 Lo = DAG.getNode(ISD::ZERO_EXTEND, dlLo, NVT, Lo);
998 Hi = DAG.getNode(ISD::ANY_EXTEND, dlHi, NVT, Hi);
999 Hi = DAG.getNode(ISD::SHL, dlHi, NVT, Hi,
1000 DAG.getConstant(LVT.getSizeInBits(), dlHi, ShiftAmtVT));
1001 return DAG.getNode(ISD::OR, dlHi, NVT, Lo, Hi);
1002 }
1003
1004 /// Promote the given target boolean to a target boolean of the given type.
1005 /// A target boolean is an integer value, not necessarily of type i1, the bits
1006 /// of which conform to getBooleanContents.
1007 ///
1008 /// ValVT is the type of values that produced the boolean.
PromoteTargetBoolean(SDValue Bool,EVT ValVT)1009 SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT ValVT) {
1010 SDLoc dl(Bool);
1011 EVT BoolVT = getSetCCResultType(ValVT);
1012 ISD::NodeType ExtendCode =
1013 TargetLowering::getExtendForContent(TLI.getBooleanContents(ValVT));
1014 return DAG.getNode(ExtendCode, dl, BoolVT, Bool);
1015 }
1016
1017 /// Return the lower LoVT bits of Op in Lo and the upper HiVT bits in Hi.
SplitInteger(SDValue Op,EVT LoVT,EVT HiVT,SDValue & Lo,SDValue & Hi)1018 void DAGTypeLegalizer::SplitInteger(SDValue Op,
1019 EVT LoVT, EVT HiVT,
1020 SDValue &Lo, SDValue &Hi) {
1021 SDLoc dl(Op);
1022 assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() ==
1023 Op.getValueSizeInBits() && "Invalid integer splitting!");
1024 Lo = DAG.getNode(ISD::TRUNCATE, dl, LoVT, Op);
1025 unsigned ReqShiftAmountInBits =
1026 Log2_32_Ceil(Op.getValueType().getSizeInBits());
1027 MVT ShiftAmountTy =
1028 TLI.getScalarShiftAmountTy(DAG.getDataLayout(), Op.getValueType());
1029 if (ReqShiftAmountInBits > ShiftAmountTy.getSizeInBits())
1030 ShiftAmountTy = MVT::getIntegerVT(NextPowerOf2(ReqShiftAmountInBits));
1031 Hi = DAG.getNode(ISD::SRL, dl, Op.getValueType(), Op,
1032 DAG.getConstant(LoVT.getSizeInBits(), dl, ShiftAmountTy));
1033 Hi = DAG.getNode(ISD::TRUNCATE, dl, HiVT, Hi);
1034 }
1035
1036 /// Return the lower and upper halves of Op's bits in a value type half the
1037 /// size of Op's.
SplitInteger(SDValue Op,SDValue & Lo,SDValue & Hi)1038 void DAGTypeLegalizer::SplitInteger(SDValue Op,
1039 SDValue &Lo, SDValue &Hi) {
1040 EVT HalfVT =
1041 EVT::getIntegerVT(*DAG.getContext(), Op.getValueSizeInBits() / 2);
1042 SplitInteger(Op, HalfVT, HalfVT, Lo, Hi);
1043 }
1044
1045
1046 //===----------------------------------------------------------------------===//
1047 // Entry Point
1048 //===----------------------------------------------------------------------===//
1049
1050 /// This transforms the SelectionDAG into a SelectionDAG that only uses types
1051 /// natively supported by the target. Returns "true" if it made any changes.
1052 ///
1053 /// Note that this is an involved process that may invalidate pointers into
1054 /// the graph.
LegalizeTypes()1055 bool SelectionDAG::LegalizeTypes() {
1056 return DAGTypeLegalizer(*this).run();
1057 }
1058