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 "llvm/ADT/SetVector.h"
17#include "llvm/IR/DataLayout.h"
18#include "llvm/Support/CommandLine.h"
19#include "llvm/Support/ErrorHandling.h"
20#include "llvm/Support/raw_ostream.h"
21using namespace llvm;
22
23#define DEBUG_TYPE "legalize-types"
24
25static cl::opt<bool>
26EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden);
27
28/// Do extensive, expensive, basic correctness checking.
29void DAGTypeLegalizer::PerformExpensiveChecks() {
30 // If a node is not processed, then none of its values should be mapped by any
31 // of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
32
33 // If a node is processed, then each value with an illegal type must be mapped
34 // by exactly one of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
35 // Values with a legal type may be mapped by ReplacedValues, but not by any of
36 // the other maps.
37
38 // Note that these invariants may not hold momentarily when processing a node:
39 // the node being processed may be put in a map before being marked Processed.
40
41 // Note that it is possible to have nodes marked NewNode in the DAG. This can
42 // occur in two ways. Firstly, a node may be created during legalization but
43 // never passed to the legalization core. This is usually due to the implicit
44 // folding that occurs when using the DAG.getNode operators. Secondly, a new
45 // node may be passed to the legalization core, but when analyzed may morph
46 // into a different node, leaving the original node as a NewNode in the DAG.
47 // A node may morph if one of its operands changes during analysis. Whether
48 // it actually morphs or not depends on whether, after updating its operands,
49 // it is equivalent to an existing node: if so, it morphs into that existing
50 // node (CSE). An operand can change during analysis if the operand is a new
51 // node that morphs, or it is a processed value that was mapped to some other
52 // value (as recorded in ReplacedValues) in which case the operand is turned
53 // into that other value. If a node morphs then the node it morphed into will
54 // be used instead of it for legalization, however the original node continues
55 // to live on in the DAG.
56 // The conclusion is that though there may be nodes marked NewNode in the DAG,
57 // all uses of such nodes are also marked NewNode: the result is a fungus of
58 // NewNodes growing on top of the useful nodes, and perhaps using them, but
59 // not used by them.
60
61 // If a value is mapped by ReplacedValues, then it must have no uses, except
62 // by nodes marked NewNode (see above).
63
64 // The final node obtained by mapping by ReplacedValues is not marked NewNode.
65 // Note that ReplacedValues should be applied iteratively.
66
67 // Note that the ReplacedValues map may also map deleted nodes (by iterating
68 // over the DAG we never dereference deleted nodes). This means that it may
69 // also map nodes marked NewNode if the deallocated memory was reallocated as
70 // another node, and that new node was not seen by the LegalizeTypes machinery
71 // (for example because it was created but not used). In general, we cannot
72 // distinguish between new nodes and deleted nodes.
73 SmallVector<SDNode*, 16> NewNodes;
74 for (SDNode &Node : DAG.allnodes()) {
75 // Remember nodes marked NewNode - they are subject to extra checking below.
76 if (Node.getNodeId() == NewNode)
77 NewNodes.push_back(Elt: &Node);
78
79 for (unsigned i = 0, e = Node.getNumValues(); i != e; ++i) {
80 SDValue Res(&Node, i);
81 bool Failed = false;
82 // Don't create a value in map.
83 auto ResId = ValueToIdMap.lookup(Val: Res);
84
85 unsigned Mapped = 0;
86 if (ResId) {
87 auto I = ReplacedValues.find(Val: ResId);
88 if (I != ReplacedValues.end()) {
89 Mapped |= 1;
90 // Check that remapped values are only used by nodes marked NewNode.
91 for (SDNode::use_iterator UI = Node.use_begin(), UE = Node.use_end();
92 UI != UE; ++UI)
93 if (UI.getUse().getResNo() == i)
94 assert(UI->getNodeId() == NewNode &&
95 "Remapped value has non-trivial use!");
96
97 // Check that the final result of applying ReplacedValues is not
98 // marked NewNode.
99 auto NewValId = I->second;
100 I = ReplacedValues.find(Val: NewValId);
101 while (I != ReplacedValues.end()) {
102 NewValId = I->second;
103 I = ReplacedValues.find(Val: NewValId);
104 }
105 SDValue NewVal = getSDValue(Id&: NewValId);
106 (void)NewVal;
107 assert(NewVal.getNode()->getNodeId() != NewNode &&
108 "ReplacedValues maps to a new node!");
109 }
110 if (PromotedIntegers.count(Val: ResId))
111 Mapped |= 2;
112 if (SoftenedFloats.count(Val: ResId))
113 Mapped |= 4;
114 if (ScalarizedVectors.count(Val: ResId))
115 Mapped |= 8;
116 if (ExpandedIntegers.count(Val: ResId))
117 Mapped |= 16;
118 if (ExpandedFloats.count(Val: ResId))
119 Mapped |= 32;
120 if (SplitVectors.count(Val: ResId))
121 Mapped |= 64;
122 if (WidenedVectors.count(Val: ResId))
123 Mapped |= 128;
124 if (PromotedFloats.count(Val: ResId))
125 Mapped |= 256;
126 if (SoftPromotedHalfs.count(Val: ResId))
127 Mapped |= 512;
128 }
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(VT: Res.getValueType()) || IgnoreNodeResults(N: &Node)) {
140 if (Mapped > 1) {
141 dbgs() << "Value with legal type was transformed!";
142 Failed = true;
143 }
144 } else {
145 if (Mapped == 0) {
146 SDValue NodeById = IdToValueMap.lookup(Val: ResId);
147 // It is possible the node has been remapped to another node and had
148 // its Id updated in the Value to Id table. The node it remapped to
149 // may not have been processed yet. Look up the Id in the Id to Value
150 // table and re-check the Processed state. If the node hasn't been
151 // remapped we'll get the same state as we got earlier.
152 if (NodeById->getNodeId() == Processed) {
153 dbgs() << "Processed value not in any map!";
154 Failed = true;
155 }
156 } else if (Mapped & (Mapped - 1)) {
157 dbgs() << "Value in multiple maps!";
158 Failed = true;
159 }
160 }
161
162 if (Failed) {
163 if (Mapped & 1)
164 dbgs() << " ReplacedValues";
165 if (Mapped & 2)
166 dbgs() << " PromotedIntegers";
167 if (Mapped & 4)
168 dbgs() << " SoftenedFloats";
169 if (Mapped & 8)
170 dbgs() << " ScalarizedVectors";
171 if (Mapped & 16)
172 dbgs() << " ExpandedIntegers";
173 if (Mapped & 32)
174 dbgs() << " ExpandedFloats";
175 if (Mapped & 64)
176 dbgs() << " SplitVectors";
177 if (Mapped & 128)
178 dbgs() << " WidenedVectors";
179 if (Mapped & 256)
180 dbgs() << " PromotedFloats";
181 if (Mapped & 512)
182 dbgs() << " SoftPromoteHalfs";
183 dbgs() << "\n";
184 llvm_unreachable(nullptr);
185 }
186 }
187 }
188
189#ifndef NDEBUG
190 // Checked that NewNodes are only used by other NewNodes.
191 for (SDNode *N : NewNodes) {
192 for (SDNode *U : N->uses())
193 assert(U->getNodeId() == NewNode && "NewNode used by non-NewNode!");
194 }
195#endif
196}
197
198/// This is the main entry point for the type legalizer. This does a top-down
199/// traversal of the dag, legalizing types as it goes. Returns "true" if it made
200/// any changes.
201bool DAGTypeLegalizer::run() {
202 bool Changed = false;
203
204 // Create a dummy node (which is not added to allnodes), that adds a reference
205 // to the root node, preventing it from being deleted, and tracking any
206 // changes of the root.
207 HandleSDNode Dummy(DAG.getRoot());
208 Dummy.setNodeId(Unanalyzed);
209
210 // The root of the dag may dangle to deleted nodes until the type legalizer is
211 // done. Set it to null to avoid confusion.
212 DAG.setRoot(SDValue());
213
214 // Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess'
215 // (and remembering them) if they are leaves and assigning 'Unanalyzed' if
216 // non-leaves.
217 for (SDNode &Node : DAG.allnodes()) {
218 if (Node.getNumOperands() == 0) {
219 Node.setNodeId(ReadyToProcess);
220 Worklist.push_back(Elt: &Node);
221 } else {
222 Node.setNodeId(Unanalyzed);
223 }
224 }
225
226 // Now that we have a set of nodes to process, handle them all.
227 while (!Worklist.empty()) {
228#ifndef EXPENSIVE_CHECKS
229 if (EnableExpensiveChecks)
230#endif
231 PerformExpensiveChecks();
232
233 SDNode *N = Worklist.pop_back_val();
234 assert(N->getNodeId() == ReadyToProcess &&
235 "Node should be ready if on worklist!");
236
237 LLVM_DEBUG(dbgs() << "\nLegalizing node: "; N->dump(&DAG));
238 if (IgnoreNodeResults(N)) {
239 LLVM_DEBUG(dbgs() << "Ignoring node results\n");
240 goto ScanOperands;
241 }
242
243 // Scan the values produced by the node, checking to see if any result
244 // types are illegal.
245 for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) {
246 EVT ResultVT = N->getValueType(ResNo: i);
247 LLVM_DEBUG(dbgs() << "Analyzing result type: " << ResultVT << "\n");
248 switch (getTypeAction(VT: ResultVT)) {
249 case TargetLowering::TypeLegal:
250 LLVM_DEBUG(dbgs() << "Legal result type\n");
251 break;
252 case TargetLowering::TypeScalarizeScalableVector:
253 report_fatal_error(
254 reason: "Scalarization of scalable vectors is not supported.");
255 // The following calls must take care of *all* of the node's results,
256 // not just the illegal result they were passed (this includes results
257 // with a legal type). Results can be remapped using ReplaceValueWith,
258 // or their promoted/expanded/etc values registered in PromotedIntegers,
259 // ExpandedIntegers etc.
260 case TargetLowering::TypePromoteInteger:
261 PromoteIntegerResult(N, ResNo: i);
262 Changed = true;
263 goto NodeDone;
264 case TargetLowering::TypeExpandInteger:
265 ExpandIntegerResult(N, ResNo: i);
266 Changed = true;
267 goto NodeDone;
268 case TargetLowering::TypeSoftenFloat:
269 SoftenFloatResult(N, ResNo: i);
270 Changed = true;
271 goto NodeDone;
272 case TargetLowering::TypeExpandFloat:
273 ExpandFloatResult(N, ResNo: i);
274 Changed = true;
275 goto NodeDone;
276 case TargetLowering::TypeScalarizeVector:
277 ScalarizeVectorResult(N, ResNo: i);
278 Changed = true;
279 goto NodeDone;
280 case TargetLowering::TypeSplitVector:
281 SplitVectorResult(N, ResNo: i);
282 Changed = true;
283 goto NodeDone;
284 case TargetLowering::TypeWidenVector:
285 WidenVectorResult(N, ResNo: i);
286 Changed = true;
287 goto NodeDone;
288 case TargetLowering::TypePromoteFloat:
289 PromoteFloatResult(N, ResNo: i);
290 Changed = true;
291 goto NodeDone;
292 case TargetLowering::TypeSoftPromoteHalf:
293 SoftPromoteHalfResult(N, ResNo: i);
294 Changed = true;
295 goto NodeDone;
296 }
297 }
298
299ScanOperands:
300 // Scan the operand list for the node, handling any nodes with operands that
301 // are illegal.
302 {
303 unsigned NumOperands = N->getNumOperands();
304 bool NeedsReanalyzing = false;
305 unsigned i;
306 for (i = 0; i != NumOperands; ++i) {
307 if (IgnoreNodeResults(N: N->getOperand(Num: i).getNode()))
308 continue;
309
310 const auto &Op = N->getOperand(Num: i);
311 LLVM_DEBUG(dbgs() << "Analyzing operand: "; Op.dump(&DAG));
312 EVT OpVT = Op.getValueType();
313 switch (getTypeAction(VT: OpVT)) {
314 case TargetLowering::TypeLegal:
315 LLVM_DEBUG(dbgs() << "Legal operand\n");
316 continue;
317 case TargetLowering::TypeScalarizeScalableVector:
318 report_fatal_error(
319 reason: "Scalarization of scalable vectors is not supported.");
320 // The following calls must either replace all of the node's results
321 // using ReplaceValueWith, and return "false"; or update the node's
322 // operands in place, and return "true".
323 case TargetLowering::TypePromoteInteger:
324 NeedsReanalyzing = PromoteIntegerOperand(N, OpNo: i);
325 Changed = true;
326 break;
327 case TargetLowering::TypeExpandInteger:
328 NeedsReanalyzing = ExpandIntegerOperand(N, OpNo: i);
329 Changed = true;
330 break;
331 case TargetLowering::TypeSoftenFloat:
332 NeedsReanalyzing = SoftenFloatOperand(N, OpNo: i);
333 Changed = true;
334 break;
335 case TargetLowering::TypeExpandFloat:
336 NeedsReanalyzing = ExpandFloatOperand(N, OpNo: i);
337 Changed = true;
338 break;
339 case TargetLowering::TypeScalarizeVector:
340 NeedsReanalyzing = ScalarizeVectorOperand(N, OpNo: i);
341 Changed = true;
342 break;
343 case TargetLowering::TypeSplitVector:
344 NeedsReanalyzing = SplitVectorOperand(N, OpNo: i);
345 Changed = true;
346 break;
347 case TargetLowering::TypeWidenVector:
348 NeedsReanalyzing = WidenVectorOperand(N, OpNo: i);
349 Changed = true;
350 break;
351 case TargetLowering::TypePromoteFloat:
352 NeedsReanalyzing = PromoteFloatOperand(N, OpNo: i);
353 Changed = true;
354 break;
355 case TargetLowering::TypeSoftPromoteHalf:
356 NeedsReanalyzing = SoftPromoteHalfOperand(N, OpNo: i);
357 Changed = true;
358 break;
359 }
360 break;
361 }
362
363 // The sub-method updated N in place. Check to see if any operands are new,
364 // and if so, mark them. If the node needs revisiting, don't add all users
365 // to the worklist etc.
366 if (NeedsReanalyzing) {
367 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
368
369 N->setNodeId(NewNode);
370 // Recompute the NodeId and correct processed operands, adding the node to
371 // the worklist if ready.
372 SDNode *M = AnalyzeNewNode(N);
373 if (M == N)
374 // The node didn't morph - nothing special to do, it will be revisited.
375 continue;
376
377 // The node morphed - this is equivalent to legalizing by replacing every
378 // value of N with the corresponding value of M. So do that now.
379 assert(N->getNumValues() == M->getNumValues() &&
380 "Node morphing changed the number of results!");
381 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
382 // Replacing the value takes care of remapping the new value.
383 ReplaceValueWith(From: SDValue(N, i), To: SDValue(M, i));
384 assert(N->getNodeId() == NewNode && "Unexpected node state!");
385 // The node continues to live on as part of the NewNode fungus that
386 // grows on top of the useful nodes. Nothing more needs to be done
387 // with it - move on to the next node.
388 continue;
389 }
390
391 if (i == NumOperands) {
392 LLVM_DEBUG(dbgs() << "Legally typed node: "; N->dump(&DAG));
393 }
394 }
395NodeDone:
396
397 // If we reach here, the node was processed, potentially creating new nodes.
398 // Mark it as processed and add its users to the worklist as appropriate.
399 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
400 N->setNodeId(Processed);
401
402 for (SDNode *User : N->uses()) {
403 int NodeId = User->getNodeId();
404
405 // This node has two options: it can either be a new node or its Node ID
406 // may be a count of the number of operands it has that are not ready.
407 if (NodeId > 0) {
408 User->setNodeId(NodeId-1);
409
410 // If this was the last use it was waiting on, add it to the ready list.
411 if (NodeId-1 == ReadyToProcess)
412 Worklist.push_back(Elt: User);
413 continue;
414 }
415
416 // If this is an unreachable new node, then ignore it. If it ever becomes
417 // reachable by being used by a newly created node then it will be handled
418 // by AnalyzeNewNode.
419 if (NodeId == NewNode)
420 continue;
421
422 // Otherwise, this node is new: this is the first operand of it that
423 // became ready. Its new NodeId is the number of operands it has minus 1
424 // (as this node is now processed).
425 assert(NodeId == Unanalyzed && "Unknown node ID!");
426 User->setNodeId(User->getNumOperands() - 1);
427
428 // If the node only has a single operand, it is now ready.
429 if (User->getNumOperands() == 1)
430 Worklist.push_back(Elt: User);
431 }
432 }
433
434#ifndef EXPENSIVE_CHECKS
435 if (EnableExpensiveChecks)
436#endif
437 PerformExpensiveChecks();
438
439 // If the root changed (e.g. it was a dead load) update the root.
440 DAG.setRoot(Dummy.getValue());
441
442 // Remove dead nodes. This is important to do for cleanliness but also before
443 // the checking loop below. Implicit folding by the DAG.getNode operators and
444 // node morphing can cause unreachable nodes to be around with their flags set
445 // to new.
446 DAG.RemoveDeadNodes();
447
448 // In a debug build, scan all the nodes to make sure we found them all. This
449 // ensures that there are no cycles and that everything got processed.
450#ifndef NDEBUG
451 for (SDNode &Node : DAG.allnodes()) {
452 bool Failed = false;
453
454 // Check that all result types are legal.
455 if (!IgnoreNodeResults(&Node))
456 for (unsigned i = 0, NumVals = Node.getNumValues(); i < NumVals; ++i)
457 if (!isTypeLegal(Node.getValueType(i))) {
458 dbgs() << "Result type " << i << " illegal: ";
459 Node.dump(&DAG);
460 Failed = true;
461 }
462
463 // Check that all operand types are legal.
464 for (unsigned i = 0, NumOps = Node.getNumOperands(); i < NumOps; ++i)
465 if (!IgnoreNodeResults(Node.getOperand(i).getNode()) &&
466 !isTypeLegal(Node.getOperand(i).getValueType())) {
467 dbgs() << "Operand type " << i << " illegal: ";
468 Node.getOperand(i).dump(&DAG);
469 Failed = true;
470 }
471
472 if (Node.getNodeId() != Processed) {
473 if (Node.getNodeId() == NewNode)
474 dbgs() << "New node not analyzed?\n";
475 else if (Node.getNodeId() == Unanalyzed)
476 dbgs() << "Unanalyzed node not noticed?\n";
477 else if (Node.getNodeId() > 0)
478 dbgs() << "Operand not processed?\n";
479 else if (Node.getNodeId() == ReadyToProcess)
480 dbgs() << "Not added to worklist?\n";
481 Failed = true;
482 }
483
484 if (Failed) {
485 Node.dump(&DAG); dbgs() << "\n";
486 llvm_unreachable(nullptr);
487 }
488 }
489#endif
490
491 return Changed;
492}
493
494/// The specified node is the root of a subtree of potentially new nodes.
495/// Correct any processed operands (this may change the node) and calculate the
496/// NodeId. If the node itself changes to a processed node, it is not remapped -
497/// the caller needs to take care of this. Returns the potentially changed node.
498SDNode *DAGTypeLegalizer::AnalyzeNewNode(SDNode *N) {
499 // If this was an existing node that is already done, we're done.
500 if (N->getNodeId() != NewNode && N->getNodeId() != Unanalyzed)
501 return N;
502
503 // Okay, we know that this node is new. Recursively walk all of its operands
504 // to see if they are new also. The depth of this walk is bounded by the size
505 // of the new tree that was constructed (usually 2-3 nodes), so we don't worry
506 // about revisiting of nodes.
507 //
508 // As we walk the operands, keep track of the number of nodes that are
509 // processed. If non-zero, this will become the new nodeid of this node.
510 // Operands may morph when they are analyzed. If so, the node will be
511 // updated after all operands have been analyzed. Since this is rare,
512 // the code tries to minimize overhead in the non-morphing case.
513
514 std::vector<SDValue> NewOps;
515 unsigned NumProcessed = 0;
516 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
517 SDValue OrigOp = N->getOperand(Num: i);
518 SDValue Op = OrigOp;
519
520 AnalyzeNewValue(Val&: Op); // Op may morph.
521
522 if (Op.getNode()->getNodeId() == Processed)
523 ++NumProcessed;
524
525 if (!NewOps.empty()) {
526 // Some previous operand changed. Add this one to the list.
527 NewOps.push_back(x: Op);
528 } else if (Op != OrigOp) {
529 // This is the first operand to change - add all operands so far.
530 NewOps.insert(position: NewOps.end(), first: N->op_begin(), last: N->op_begin() + i);
531 NewOps.push_back(x: Op);
532 }
533 }
534
535 // Some operands changed - update the node.
536 if (!NewOps.empty()) {
537 SDNode *M = DAG.UpdateNodeOperands(N, Ops: NewOps);
538 if (M != N) {
539 // The node morphed into a different node. Normally for this to happen
540 // the original node would have to be marked NewNode. However this can
541 // in theory momentarily not be the case while ReplaceValueWith is doing
542 // its stuff. Mark the original node NewNode to help basic correctness
543 // checking.
544 N->setNodeId(NewNode);
545 if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed)
546 // It morphed into a previously analyzed node - nothing more to do.
547 return M;
548
549 // It morphed into a different new node. Do the equivalent of passing
550 // it to AnalyzeNewNode: expunge it and calculate the NodeId. No need
551 // to remap the operands, since they are the same as the operands we
552 // remapped above.
553 N = M;
554 }
555 }
556
557 // Calculate the NodeId.
558 N->setNodeId(N->getNumOperands() - NumProcessed);
559 if (N->getNodeId() == ReadyToProcess)
560 Worklist.push_back(Elt: N);
561
562 return N;
563}
564
565/// Call AnalyzeNewNode, updating the node in Val if needed.
566/// If the node changes to a processed node, then remap it.
567void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) {
568 Val.setNode(AnalyzeNewNode(N: Val.getNode()));
569 if (Val.getNode()->getNodeId() == Processed)
570 // We were passed a processed node, or it morphed into one - remap it.
571 RemapValue(V&: Val);
572}
573
574/// If the specified value was already legalized to another value,
575/// replace it by that value.
576void DAGTypeLegalizer::RemapValue(SDValue &V) {
577 auto Id = getTableId(V);
578 V = getSDValue(Id);
579}
580
581void DAGTypeLegalizer::RemapId(TableId &Id) {
582 auto I = ReplacedValues.find(Val: Id);
583 if (I != ReplacedValues.end()) {
584 assert(Id != I->second && "Id is mapped to itself.");
585 // Use path compression to speed up future lookups if values get multiply
586 // replaced with other values.
587 RemapId(Id&: I->second);
588 Id = I->second;
589
590 // Note that N = IdToValueMap[Id] it is possible to have
591 // N.getNode()->getNodeId() == NewNode at this point because it is possible
592 // for a node to be put in the map before being processed.
593 }
594}
595
596namespace {
597 /// This class is a DAGUpdateListener that listens for updates to nodes and
598 /// recomputes their ready state.
599 class NodeUpdateListener : public SelectionDAG::DAGUpdateListener {
600 DAGTypeLegalizer &DTL;
601 SmallSetVector<SDNode*, 16> &NodesToAnalyze;
602 public:
603 explicit NodeUpdateListener(DAGTypeLegalizer &dtl,
604 SmallSetVector<SDNode*, 16> &nta)
605 : SelectionDAG::DAGUpdateListener(dtl.getDAG()),
606 DTL(dtl), NodesToAnalyze(nta) {}
607
608 void NodeDeleted(SDNode *N, SDNode *E) override {
609 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
610 N->getNodeId() != DAGTypeLegalizer::Processed &&
611 "Invalid node ID for RAUW deletion!");
612 // It is possible, though rare, for the deleted node N to occur as a
613 // target in a map, so note the replacement N -> E in ReplacedValues.
614 assert(E && "Node not replaced?");
615 DTL.NoteDeletion(Old: N, New: E);
616
617 // In theory the deleted node could also have been scheduled for analysis.
618 // So remove it from the set of nodes which will be analyzed.
619 NodesToAnalyze.remove(X: N);
620
621 // In general nothing needs to be done for E, since it didn't change but
622 // only gained new uses. However N -> E was just added to ReplacedValues,
623 // and the result of a ReplacedValues mapping is not allowed to be marked
624 // NewNode. So if E is marked NewNode, then it needs to be analyzed.
625 if (E->getNodeId() == DAGTypeLegalizer::NewNode)
626 NodesToAnalyze.insert(X: E);
627 }
628
629 void NodeUpdated(SDNode *N) override {
630 // Node updates can mean pretty much anything. It is possible that an
631 // operand was set to something already processed (f.e.) in which case
632 // this node could become ready. Recompute its flags.
633 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
634 N->getNodeId() != DAGTypeLegalizer::Processed &&
635 "Invalid node ID for RAUW deletion!");
636 N->setNodeId(DAGTypeLegalizer::NewNode);
637 NodesToAnalyze.insert(X: N);
638 }
639 };
640}
641
642
643/// The specified value was legalized to the specified other value.
644/// Update the DAG and NodeIds replacing any uses of From to use To instead.
645void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) {
646 assert(From.getNode() != To.getNode() && "Potential legalization loop!");
647
648 // If expansion produced new nodes, make sure they are properly marked.
649 AnalyzeNewValue(Val&: To);
650
651 // Anything that used the old node should now use the new one. Note that this
652 // can potentially cause recursive merging.
653 SmallSetVector<SDNode*, 16> NodesToAnalyze;
654 NodeUpdateListener NUL(*this, NodesToAnalyze);
655 do {
656
657 // The old node may be present in a map like ExpandedIntegers or
658 // PromotedIntegers. Inform maps about the replacement.
659 auto FromId = getTableId(V: From);
660 auto ToId = getTableId(V: To);
661
662 if (FromId != ToId)
663 ReplacedValues[FromId] = ToId;
664 DAG.ReplaceAllUsesOfValueWith(From, To);
665
666 // Process the list of nodes that need to be reanalyzed.
667 while (!NodesToAnalyze.empty()) {
668 SDNode *N = NodesToAnalyze.pop_back_val();
669 if (N->getNodeId() != DAGTypeLegalizer::NewNode)
670 // The node was analyzed while reanalyzing an earlier node - it is safe
671 // to skip. Note that this is not a morphing node - otherwise it would
672 // still be marked NewNode.
673 continue;
674
675 // Analyze the node's operands and recalculate the node ID.
676 SDNode *M = AnalyzeNewNode(N);
677 if (M != N) {
678 // The node morphed into a different node. Make everyone use the new
679 // node instead.
680 assert(M->getNodeId() != NewNode && "Analysis resulted in NewNode!");
681 assert(N->getNumValues() == M->getNumValues() &&
682 "Node morphing changed the number of results!");
683 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) {
684 SDValue OldVal(N, i);
685 SDValue NewVal(M, i);
686 if (M->getNodeId() == Processed)
687 RemapValue(V&: NewVal);
688 // OldVal may be a target of the ReplacedValues map which was marked
689 // NewNode to force reanalysis because it was updated. Ensure that
690 // anything that ReplacedValues mapped to OldVal will now be mapped
691 // all the way to NewVal.
692 auto OldValId = getTableId(V: OldVal);
693 auto NewValId = getTableId(V: NewVal);
694 DAG.ReplaceAllUsesOfValueWith(From: OldVal, To: NewVal);
695 if (OldValId != NewValId)
696 ReplacedValues[OldValId] = NewValId;
697 }
698 // The original node continues to exist in the DAG, marked NewNode.
699 }
700 }
701 // When recursively update nodes with new nodes, it is possible to have
702 // new uses of From due to CSE. If this happens, replace the new uses of
703 // From with To.
704 } while (!From.use_empty());
705}
706
707void DAGTypeLegalizer::SetPromotedInteger(SDValue Op, SDValue Result) {
708 assert(Result.getValueType() ==
709 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
710 "Invalid type for promoted integer");
711 AnalyzeNewValue(Val&: Result);
712
713 auto &OpIdEntry = PromotedIntegers[getTableId(V: Op)];
714 assert((OpIdEntry == 0) && "Node is already promoted!");
715 OpIdEntry = getTableId(V: Result);
716
717 DAG.transferDbgValues(From: Op, To: Result);
718}
719
720void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) {
721#ifndef NDEBUG
722 EVT VT = Result.getValueType();
723 LLVMContext &Ctx = *DAG.getContext();
724 assert((VT == EVT::getIntegerVT(Ctx, 80) ||
725 VT == TLI.getTypeToTransformTo(Ctx, Op.getValueType())) &&
726 "Invalid type for softened float");
727#endif
728 AnalyzeNewValue(Val&: Result);
729
730 auto &OpIdEntry = SoftenedFloats[getTableId(V: Op)];
731 assert((OpIdEntry == 0) && "Node is already converted to integer!");
732 OpIdEntry = getTableId(V: Result);
733}
734
735void DAGTypeLegalizer::SetPromotedFloat(SDValue Op, SDValue Result) {
736 assert(Result.getValueType() ==
737 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
738 "Invalid type for promoted float");
739 AnalyzeNewValue(Val&: Result);
740
741 auto &OpIdEntry = PromotedFloats[getTableId(V: Op)];
742 assert((OpIdEntry == 0) && "Node is already promoted!");
743 OpIdEntry = getTableId(V: Result);
744}
745
746void DAGTypeLegalizer::SetSoftPromotedHalf(SDValue Op, SDValue Result) {
747 assert(Result.getValueType() == MVT::i16 &&
748 "Invalid type for soft-promoted half");
749 AnalyzeNewValue(Val&: Result);
750
751 auto &OpIdEntry = SoftPromotedHalfs[getTableId(V: Op)];
752 assert((OpIdEntry == 0) && "Node is already promoted!");
753 OpIdEntry = getTableId(V: Result);
754}
755
756void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) {
757 // Note that in some cases vector operation operands may be greater than
758 // the vector element type. For example BUILD_VECTOR of type <1 x i1> with
759 // a constant i8 operand.
760
761 // We don't currently support the scalarization of scalable vector types.
762 assert(Result.getValueSizeInBits().getFixedValue() >=
763 Op.getScalarValueSizeInBits() &&
764 "Invalid type for scalarized vector");
765 AnalyzeNewValue(Val&: Result);
766
767 auto &OpIdEntry = ScalarizedVectors[getTableId(V: Op)];
768 assert((OpIdEntry == 0) && "Node is already scalarized!");
769 OpIdEntry = getTableId(V: Result);
770}
771
772void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo,
773 SDValue &Hi) {
774 std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(V: Op)];
775 assert((Entry.first != 0) && "Operand isn't expanded");
776 Lo = getSDValue(Id&: Entry.first);
777 Hi = getSDValue(Id&: Entry.second);
778}
779
780void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo,
781 SDValue Hi) {
782 assert(Lo.getValueType() ==
783 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
784 Hi.getValueType() == Lo.getValueType() &&
785 "Invalid type for expanded integer");
786 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
787 AnalyzeNewValue(Val&: Lo);
788 AnalyzeNewValue(Val&: Hi);
789
790 // Transfer debug values. Don't invalidate the source debug value until it's
791 // been transferred to the high and low bits.
792 if (DAG.getDataLayout().isBigEndian()) {
793 DAG.transferDbgValues(From: Op, To: Hi, OffsetInBits: 0, SizeInBits: Hi.getValueSizeInBits(), InvalidateDbg: false);
794 DAG.transferDbgValues(From: Op, To: Lo, OffsetInBits: Hi.getValueSizeInBits(),
795 SizeInBits: Lo.getValueSizeInBits());
796 } else {
797 DAG.transferDbgValues(From: Op, To: Lo, OffsetInBits: 0, SizeInBits: Lo.getValueSizeInBits(), InvalidateDbg: false);
798 DAG.transferDbgValues(From: Op, To: Hi, OffsetInBits: Lo.getValueSizeInBits(),
799 SizeInBits: Hi.getValueSizeInBits());
800 }
801
802 // Remember that this is the result of the node.
803 std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(V: Op)];
804 assert((Entry.first == 0) && "Node already expanded");
805 Entry.first = getTableId(V: Lo);
806 Entry.second = getTableId(V: Hi);
807}
808
809void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo,
810 SDValue &Hi) {
811 std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(V: Op)];
812 assert((Entry.first != 0) && "Operand isn't expanded");
813 Lo = getSDValue(Id&: Entry.first);
814 Hi = getSDValue(Id&: Entry.second);
815}
816
817void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo,
818 SDValue Hi) {
819 assert(Lo.getValueType() ==
820 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
821 Hi.getValueType() == Lo.getValueType() &&
822 "Invalid type for expanded float");
823 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
824 AnalyzeNewValue(Val&: Lo);
825 AnalyzeNewValue(Val&: Hi);
826
827 std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(V: Op)];
828 assert((Entry.first == 0) && "Node already expanded");
829 Entry.first = getTableId(V: Lo);
830 Entry.second = getTableId(V: Hi);
831}
832
833void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo,
834 SDValue &Hi) {
835 std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(V: Op)];
836 Lo = getSDValue(Id&: Entry.first);
837 Hi = getSDValue(Id&: Entry.second);
838 assert(Lo.getNode() && "Operand isn't split");
839 ;
840}
841
842void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo,
843 SDValue Hi) {
844 assert(Lo.getValueType().getVectorElementType() ==
845 Op.getValueType().getVectorElementType() &&
846 Lo.getValueType().getVectorElementCount() * 2 ==
847 Op.getValueType().getVectorElementCount() &&
848 Hi.getValueType() == Lo.getValueType() &&
849 "Invalid type for split vector");
850 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
851 AnalyzeNewValue(Val&: Lo);
852 AnalyzeNewValue(Val&: Hi);
853
854 // Remember that this is the result of the node.
855 std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(V: Op)];
856 assert((Entry.first == 0) && "Node already split");
857 Entry.first = getTableId(V: Lo);
858 Entry.second = getTableId(V: Hi);
859}
860
861void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) {
862 assert(Result.getValueType() ==
863 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
864 "Invalid type for widened vector");
865 AnalyzeNewValue(Val&: Result);
866
867 auto &OpIdEntry = WidenedVectors[getTableId(V: Op)];
868 assert((OpIdEntry == 0) && "Node already widened!");
869 OpIdEntry = getTableId(V: Result);
870}
871
872
873//===----------------------------------------------------------------------===//
874// Utilities.
875//===----------------------------------------------------------------------===//
876
877/// Convert to an integer of the same size.
878SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) {
879 unsigned BitWidth = Op.getValueSizeInBits();
880 return DAG.getNode(Opcode: ISD::BITCAST, DL: SDLoc(Op),
881 VT: EVT::getIntegerVT(Context&: *DAG.getContext(), BitWidth), Operand: Op);
882}
883
884/// Convert to a vector of integers of the same size.
885SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) {
886 assert(Op.getValueType().isVector() && "Only applies to vectors!");
887 unsigned EltWidth = Op.getScalarValueSizeInBits();
888 EVT EltNVT = EVT::getIntegerVT(Context&: *DAG.getContext(), BitWidth: EltWidth);
889 auto EltCnt = Op.getValueType().getVectorElementCount();
890 return DAG.getNode(Opcode: ISD::BITCAST, DL: SDLoc(Op),
891 VT: EVT::getVectorVT(Context&: *DAG.getContext(), VT: EltNVT, EC: EltCnt), Operand: Op);
892}
893
894SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op,
895 EVT DestVT) {
896 SDLoc dl(Op);
897 // Create the stack frame object. Make sure it is aligned for both
898 // the source and destination types.
899
900 // In cases where the vector is illegal it will be broken down into parts
901 // and stored in parts - we should use the alignment for the smallest part.
902 Align DestAlign = DAG.getReducedAlign(VT: DestVT, /*UseABI=*/false);
903 Align OpAlign = DAG.getReducedAlign(VT: Op.getValueType(), /*UseABI=*/false);
904 Align Align = std::max(a: DestAlign, b: OpAlign);
905 SDValue StackPtr =
906 DAG.CreateStackTemporary(Bytes: Op.getValueType().getStoreSize(), Alignment: Align);
907 // Emit a store to the stack slot.
908 SDValue Store = DAG.getStore(Chain: DAG.getEntryNode(), dl, Val: Op, Ptr: StackPtr,
909 PtrInfo: MachinePointerInfo(), Alignment: Align);
910 // Result is a load from the stack slot.
911 return DAG.getLoad(VT: DestVT, dl, Chain: Store, Ptr: StackPtr, PtrInfo: MachinePointerInfo(), Alignment: Align);
912}
913
914/// Replace the node's results with custom code provided by the target and
915/// return "true", or do nothing and return "false".
916/// The last parameter is FALSE if we are dealing with a node with legal
917/// result types and illegal operand. The second parameter denotes the type of
918/// illegal OperandNo in that case.
919/// The last parameter being TRUE means we are dealing with a
920/// node with illegal result types. The second parameter denotes the type of
921/// illegal ResNo in that case.
922bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) {
923 // See if the target wants to custom lower this node.
924 if (TLI.getOperationAction(Op: N->getOpcode(), VT) != TargetLowering::Custom)
925 return false;
926
927 SmallVector<SDValue, 8> Results;
928 if (LegalizeResult)
929 TLI.ReplaceNodeResults(N, Results, DAG);
930 else
931 TLI.LowerOperationWrapper(N, Results, DAG);
932
933 if (Results.empty())
934 // The target didn't want to custom lower it after all.
935 return false;
936
937 // Make everything that once used N's values now use those in Results instead.
938 assert(Results.size() == N->getNumValues() &&
939 "Custom lowering returned the wrong number of results!");
940 for (unsigned i = 0, e = Results.size(); i != e; ++i) {
941 ReplaceValueWith(From: SDValue(N, i), To: Results[i]);
942 }
943 return true;
944}
945
946
947/// Widen the node's results with custom code provided by the target and return
948/// "true", or do nothing and return "false".
949bool DAGTypeLegalizer::CustomWidenLowerNode(SDNode *N, EVT VT) {
950 // See if the target wants to custom lower this node.
951 if (TLI.getOperationAction(Op: N->getOpcode(), VT) != TargetLowering::Custom)
952 return false;
953
954 SmallVector<SDValue, 8> Results;
955 TLI.ReplaceNodeResults(N, Results, DAG);
956
957 if (Results.empty())
958 // The target didn't want to custom widen lower its result after all.
959 return false;
960
961 // Update the widening map.
962 assert(Results.size() == N->getNumValues() &&
963 "Custom lowering returned the wrong number of results!");
964 for (unsigned i = 0, e = Results.size(); i != e; ++i) {
965 // If this is a chain output or already widened just replace it.
966 bool WasWidened = SDValue(N, i).getValueType() != Results[i].getValueType();
967 if (WasWidened)
968 SetWidenedVector(Op: SDValue(N, i), Result: Results[i]);
969 else
970 ReplaceValueWith(From: SDValue(N, i), To: Results[i]);
971 }
972 return true;
973}
974
975SDValue DAGTypeLegalizer::DisintegrateMERGE_VALUES(SDNode *N, unsigned ResNo) {
976 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
977 if (i != ResNo)
978 ReplaceValueWith(From: SDValue(N, i), To: SDValue(N->getOperand(Num: i)));
979 return SDValue(N->getOperand(Num: ResNo));
980}
981
982/// Use ISD::EXTRACT_ELEMENT nodes to extract the low and high parts of the
983/// given value.
984void DAGTypeLegalizer::GetPairElements(SDValue Pair,
985 SDValue &Lo, SDValue &Hi) {
986 SDLoc dl(Pair);
987 EVT NVT = TLI.getTypeToTransformTo(Context&: *DAG.getContext(), VT: Pair.getValueType());
988 std::tie(args&: Lo, args&: Hi) = DAG.SplitScalar(N: Pair, DL: dl, LoVT: NVT, HiVT: NVT);
989}
990
991/// Build an integer with low bits Lo and high bits Hi.
992SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) {
993 // Arbitrarily use dlHi for result SDLoc
994 SDLoc dlHi(Hi);
995 SDLoc dlLo(Lo);
996 EVT LVT = Lo.getValueType();
997 EVT HVT = Hi.getValueType();
998 EVT NVT = EVT::getIntegerVT(Context&: *DAG.getContext(),
999 BitWidth: LVT.getSizeInBits() + HVT.getSizeInBits());
1000
1001 EVT ShiftAmtVT = TLI.getShiftAmountTy(LHSTy: NVT, DL: DAG.getDataLayout());
1002 Lo = DAG.getNode(Opcode: ISD::ZERO_EXTEND, DL: dlLo, VT: NVT, Operand: Lo);
1003 Hi = DAG.getNode(Opcode: ISD::ANY_EXTEND, DL: dlHi, VT: NVT, Operand: Hi);
1004 Hi = DAG.getNode(Opcode: ISD::SHL, DL: dlHi, VT: NVT, N1: Hi,
1005 N2: DAG.getConstant(Val: LVT.getSizeInBits(), DL: dlHi, VT: ShiftAmtVT));
1006 return DAG.getNode(Opcode: ISD::OR, DL: dlHi, VT: NVT, N1: Lo, N2: Hi);
1007}
1008
1009/// Promote the given target boolean to a target boolean of the given type.
1010/// A target boolean is an integer value, not necessarily of type i1, the bits
1011/// of which conform to getBooleanContents.
1012///
1013/// ValVT is the type of values that produced the boolean.
1014SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT ValVT) {
1015 return TLI.promoteTargetBoolean(DAG, Bool, ValVT);
1016}
1017
1018/// Return the lower LoVT bits of Op in Lo and the upper HiVT bits in Hi.
1019void DAGTypeLegalizer::SplitInteger(SDValue Op,
1020 EVT LoVT, EVT HiVT,
1021 SDValue &Lo, SDValue &Hi) {
1022 SDLoc dl(Op);
1023 assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() ==
1024 Op.getValueSizeInBits() && "Invalid integer splitting!");
1025 Lo = DAG.getNode(Opcode: ISD::TRUNCATE, DL: dl, VT: LoVT, Operand: Op);
1026 unsigned ReqShiftAmountInBits =
1027 Log2_32_Ceil(Value: Op.getValueType().getSizeInBits());
1028 MVT ShiftAmountTy =
1029 TLI.getScalarShiftAmountTy(DAG.getDataLayout(), Op.getValueType());
1030 if (ReqShiftAmountInBits > ShiftAmountTy.getSizeInBits())
1031 ShiftAmountTy = MVT::getIntegerVT(BitWidth: NextPowerOf2(A: ReqShiftAmountInBits));
1032 Hi = DAG.getNode(Opcode: ISD::SRL, DL: dl, VT: Op.getValueType(), N1: Op,
1033 N2: DAG.getConstant(Val: LoVT.getSizeInBits(), DL: dl, VT: ShiftAmountTy));
1034 Hi = DAG.getNode(Opcode: ISD::TRUNCATE, DL: dl, VT: HiVT, Operand: Hi);
1035}
1036
1037/// Return the lower and upper halves of Op's bits in a value type half the
1038/// size of Op's.
1039void DAGTypeLegalizer::SplitInteger(SDValue Op,
1040 SDValue &Lo, SDValue &Hi) {
1041 EVT HalfVT =
1042 EVT::getIntegerVT(Context&: *DAG.getContext(), BitWidth: Op.getValueSizeInBits() / 2);
1043 SplitInteger(Op, LoVT: HalfVT, HiVT: HalfVT, Lo, Hi);
1044}
1045
1046
1047//===----------------------------------------------------------------------===//
1048// Entry Point
1049//===----------------------------------------------------------------------===//
1050
1051/// This transforms the SelectionDAG into a SelectionDAG that only uses types
1052/// natively supported by the target. Returns "true" if it made any changes.
1053///
1054/// Note that this is an involved process that may invalidate pointers into
1055/// the graph.
1056bool SelectionDAG::LegalizeTypes() {
1057 return DAGTypeLegalizer(*this).run();
1058}
1059