1 //===-- LegalizeTypes.cpp - Common code for DAG type legalizer ------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the SelectionDAG::LegalizeTypes method. It transforms
11 // an arbitrary well-formed SelectionDAG to only consist of legal types. This
12 // is common code shared among the LegalizeTypes*.cpp files.
14 //===----------------------------------------------------------------------===//
16 #include "LegalizeTypes.h"
17 #include "llvm/ADT/SetVector.h"
18 #include "llvm/IR/CallingConv.h"
19 #include "llvm/IR/DataLayout.h"
20 #include "llvm/Support/CommandLine.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/raw_ostream.h"
25 #define DEBUG_TYPE "legalize-types"
28 EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden);
30 /// PerformExpensiveChecks - Do extensive, expensive, sanity checking.
31 void DAGTypeLegalizer::PerformExpensiveChecks() {
32 // If a node is not processed, then none of its values should be mapped by any
33 // of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
35 // If a node is processed, then each value with an illegal type must be mapped
36 // by exactly one of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues.
37 // Values with a legal type may be mapped by ReplacedValues, but not by any of
40 // Note that these invariants may not hold momentarily when processing a node:
41 // the node being processed may be put in a map before being marked Processed.
43 // Note that it is possible to have nodes marked NewNode in the DAG. This can
44 // occur in two ways. Firstly, a node may be created during legalization but
45 // never passed to the legalization core. This is usually due to the implicit
46 // folding that occurs when using the DAG.getNode operators. Secondly, a new
47 // node may be passed to the legalization core, but when analyzed may morph
48 // into a different node, leaving the original node as a NewNode in the DAG.
49 // A node may morph if one of its operands changes during analysis. Whether
50 // it actually morphs or not depends on whether, after updating its operands,
51 // it is equivalent to an existing node: if so, it morphs into that existing
52 // node (CSE). An operand can change during analysis if the operand is a new
53 // node that morphs, or it is a processed value that was mapped to some other
54 // value (as recorded in ReplacedValues) in which case the operand is turned
55 // into that other value. If a node morphs then the node it morphed into will
56 // be used instead of it for legalization, however the original node continues
57 // to live on in the DAG.
58 // The conclusion is that though there may be nodes marked NewNode in the DAG,
59 // all uses of such nodes are also marked NewNode: the result is a fungus of
60 // NewNodes growing on top of the useful nodes, and perhaps using them, but
63 // If a value is mapped by ReplacedValues, then it must have no uses, except
64 // by nodes marked NewNode (see above).
66 // The final node obtained by mapping by ReplacedValues is not marked NewNode.
67 // Note that ReplacedValues should be applied iteratively.
69 // Note that the ReplacedValues map may also map deleted nodes (by iterating
70 // over the DAG we never dereference deleted nodes). This means that it may
71 // also map nodes marked NewNode if the deallocated memory was reallocated as
72 // another node, and that new node was not seen by the LegalizeTypes machinery
73 // (for example because it was created but not used). In general, we cannot
74 // distinguish between new nodes and deleted nodes.
75 SmallVector<SDNode*, 16> NewNodes;
76 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
77 E = DAG.allnodes_end(); I != E; ++I) {
78 // Remember nodes marked NewNode - they are subject to extra checking below.
79 if (I->getNodeId() == NewNode)
80 NewNodes.push_back(I);
82 for (unsigned i = 0, e = I->getNumValues(); i != e; ++i) {
87 if (ReplacedValues.find(Res) != ReplacedValues.end()) {
89 // Check that remapped values are only used by nodes marked NewNode.
90 for (SDNode::use_iterator UI = I->use_begin(), UE = I->use_end();
92 if (UI.getUse().getResNo() == i)
93 assert(UI->getNodeId() == NewNode &&
94 "Remapped value has non-trivial use!");
96 // Check that the final result of applying ReplacedValues is not
98 SDValue NewVal = ReplacedValues[Res];
99 DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(NewVal);
100 while (I != ReplacedValues.end()) {
102 I = ReplacedValues.find(NewVal);
104 assert(NewVal.getNode()->getNodeId() != NewNode &&
105 "ReplacedValues maps to a new node!");
107 if (PromotedIntegers.find(Res) != PromotedIntegers.end())
109 if (SoftenedFloats.find(Res) != SoftenedFloats.end())
111 if (ScalarizedVectors.find(Res) != ScalarizedVectors.end())
113 if (ExpandedIntegers.find(Res) != ExpandedIntegers.end())
115 if (ExpandedFloats.find(Res) != ExpandedFloats.end())
117 if (SplitVectors.find(Res) != SplitVectors.end())
119 if (WidenedVectors.find(Res) != WidenedVectors.end())
122 if (I->getNodeId() != Processed) {
123 // Since we allow ReplacedValues to map deleted nodes, it may map nodes
124 // marked NewNode too, since a deleted node may have been reallocated as
125 // another node that has not been seen by the LegalizeTypes machinery.
126 if ((I->getNodeId() == NewNode && Mapped > 1) ||
127 (I->getNodeId() != NewNode && Mapped != 0)) {
128 dbgs() << "Unprocessed value in a map!";
131 } else if (isTypeLegal(Res.getValueType()) || IgnoreNodeResults(I)) {
133 dbgs() << "Value with legal type was transformed!";
138 dbgs() << "Processed value not in any map!";
140 } else if (Mapped & (Mapped - 1)) {
141 dbgs() << "Value in multiple maps!";
148 dbgs() << " ReplacedValues";
150 dbgs() << " PromotedIntegers";
152 dbgs() << " SoftenedFloats";
154 dbgs() << " ScalarizedVectors";
156 dbgs() << " ExpandedIntegers";
158 dbgs() << " ExpandedFloats";
160 dbgs() << " SplitVectors";
162 dbgs() << " WidenedVectors";
164 llvm_unreachable(nullptr);
169 // Checked that NewNodes are only used by other NewNodes.
170 for (unsigned i = 0, e = NewNodes.size(); i != e; ++i) {
171 SDNode *N = NewNodes[i];
172 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end();
174 assert(UI->getNodeId() == NewNode && "NewNode used by non-NewNode!");
178 /// run - This is the main entry point for the type legalizer. This does a
179 /// top-down traversal of the dag, legalizing types as it goes. Returns "true"
180 /// if it made any changes.
181 bool DAGTypeLegalizer::run() {
182 bool Changed = false;
184 // Create a dummy node (which is not added to allnodes), that adds a reference
185 // to the root node, preventing it from being deleted, and tracking any
186 // changes of the root.
187 HandleSDNode Dummy(DAG.getRoot());
188 Dummy.setNodeId(Unanalyzed);
190 // The root of the dag may dangle to deleted nodes until the type legalizer is
191 // done. Set it to null to avoid confusion.
192 DAG.setRoot(SDValue());
194 // Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess'
195 // (and remembering them) if they are leaves and assigning 'Unanalyzed' if
197 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
198 E = DAG.allnodes_end(); I != E; ++I) {
199 if (I->getNumOperands() == 0) {
200 I->setNodeId(ReadyToProcess);
201 Worklist.push_back(I);
203 I->setNodeId(Unanalyzed);
207 // Now that we have a set of nodes to process, handle them all.
208 while (!Worklist.empty()) {
210 if (EnableExpensiveChecks)
212 PerformExpensiveChecks();
214 SDNode *N = Worklist.back();
216 assert(N->getNodeId() == ReadyToProcess &&
217 "Node should be ready if on worklist!");
219 if (IgnoreNodeResults(N))
222 // Scan the values produced by the node, checking to see if any result
223 // types are illegal.
224 for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) {
225 EVT ResultVT = N->getValueType(i);
226 switch (getTypeAction(ResultVT)) {
227 case TargetLowering::TypeLegal:
229 // The following calls must take care of *all* of the node's results,
230 // not just the illegal result they were passed (this includes results
231 // with a legal type). Results can be remapped using ReplaceValueWith,
232 // or their promoted/expanded/etc values registered in PromotedIntegers,
233 // ExpandedIntegers etc.
234 case TargetLowering::TypePromoteInteger:
235 PromoteIntegerResult(N, i);
238 case TargetLowering::TypeExpandInteger:
239 ExpandIntegerResult(N, i);
242 case TargetLowering::TypeSoftenFloat:
243 SoftenFloatResult(N, i);
246 case TargetLowering::TypeExpandFloat:
247 ExpandFloatResult(N, i);
250 case TargetLowering::TypeScalarizeVector:
251 ScalarizeVectorResult(N, i);
254 case TargetLowering::TypeSplitVector:
255 SplitVectorResult(N, i);
258 case TargetLowering::TypeWidenVector:
259 WidenVectorResult(N, i);
262 case TargetLowering::TypePromoteFloat:
263 PromoteFloatResult(N, i);
270 // Scan the operand list for the node, handling any nodes with operands that
273 unsigned NumOperands = N->getNumOperands();
274 bool NeedsReanalyzing = false;
276 for (i = 0; i != NumOperands; ++i) {
277 if (IgnoreNodeResults(N->getOperand(i).getNode()))
280 EVT OpVT = N->getOperand(i).getValueType();
281 switch (getTypeAction(OpVT)) {
282 case TargetLowering::TypeLegal:
284 // The following calls must either replace all of the node's results
285 // using ReplaceValueWith, and return "false"; or update the node's
286 // operands in place, and return "true".
287 case TargetLowering::TypePromoteInteger:
288 NeedsReanalyzing = PromoteIntegerOperand(N, i);
291 case TargetLowering::TypeExpandInteger:
292 NeedsReanalyzing = ExpandIntegerOperand(N, i);
295 case TargetLowering::TypeSoftenFloat:
296 NeedsReanalyzing = SoftenFloatOperand(N, i);
299 case TargetLowering::TypeExpandFloat:
300 NeedsReanalyzing = ExpandFloatOperand(N, i);
303 case TargetLowering::TypeScalarizeVector:
304 NeedsReanalyzing = ScalarizeVectorOperand(N, i);
307 case TargetLowering::TypeSplitVector:
308 NeedsReanalyzing = SplitVectorOperand(N, i);
311 case TargetLowering::TypeWidenVector:
312 NeedsReanalyzing = WidenVectorOperand(N, i);
315 case TargetLowering::TypePromoteFloat:
316 NeedsReanalyzing = PromoteFloatOperand(N, i);
323 // The sub-method updated N in place. Check to see if any operands are new,
324 // and if so, mark them. If the node needs revisiting, don't add all users
325 // to the worklist etc.
326 if (NeedsReanalyzing) {
327 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
328 N->setNodeId(NewNode);
329 // Recompute the NodeId and correct processed operands, adding the node to
330 // the worklist if ready.
331 SDNode *M = AnalyzeNewNode(N);
333 // The node didn't morph - nothing special to do, it will be revisited.
336 // The node morphed - this is equivalent to legalizing by replacing every
337 // value of N with the corresponding value of M. So do that now.
338 assert(N->getNumValues() == M->getNumValues() &&
339 "Node morphing changed the number of results!");
340 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
341 // Replacing the value takes care of remapping the new value.
342 ReplaceValueWith(SDValue(N, i), SDValue(M, i));
343 assert(N->getNodeId() == NewNode && "Unexpected node state!");
344 // The node continues to live on as part of the NewNode fungus that
345 // grows on top of the useful nodes. Nothing more needs to be done
346 // with it - move on to the next node.
350 if (i == NumOperands) {
351 DEBUG(dbgs() << "Legally typed node: "; N->dump(&DAG); dbgs() << "\n");
356 // If we reach here, the node was processed, potentially creating new nodes.
357 // Mark it as processed and add its users to the worklist as appropriate.
358 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?");
359 N->setNodeId(Processed);
361 for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end();
364 int NodeId = User->getNodeId();
366 // This node has two options: it can either be a new node or its Node ID
367 // may be a count of the number of operands it has that are not ready.
369 User->setNodeId(NodeId-1);
371 // If this was the last use it was waiting on, add it to the ready list.
372 if (NodeId-1 == ReadyToProcess)
373 Worklist.push_back(User);
377 // If this is an unreachable new node, then ignore it. If it ever becomes
378 // reachable by being used by a newly created node then it will be handled
379 // by AnalyzeNewNode.
380 if (NodeId == NewNode)
383 // Otherwise, this node is new: this is the first operand of it that
384 // became ready. Its new NodeId is the number of operands it has minus 1
385 // (as this node is now processed).
386 assert(NodeId == Unanalyzed && "Unknown node ID!");
387 User->setNodeId(User->getNumOperands() - 1);
389 // If the node only has a single operand, it is now ready.
390 if (User->getNumOperands() == 1)
391 Worklist.push_back(User);
396 if (EnableExpensiveChecks)
398 PerformExpensiveChecks();
400 // If the root changed (e.g. it was a dead load) update the root.
401 DAG.setRoot(Dummy.getValue());
403 // Remove dead nodes. This is important to do for cleanliness but also before
404 // the checking loop below. Implicit folding by the DAG.getNode operators and
405 // node morphing can cause unreachable nodes to be around with their flags set
407 DAG.RemoveDeadNodes();
409 // In a debug build, scan all the nodes to make sure we found them all. This
410 // ensures that there are no cycles and that everything got processed.
412 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(),
413 E = DAG.allnodes_end(); I != E; ++I) {
416 // Check that all result types are legal.
417 if (!IgnoreNodeResults(I))
418 for (unsigned i = 0, NumVals = I->getNumValues(); i < NumVals; ++i)
419 if (!isTypeLegal(I->getValueType(i))) {
420 dbgs() << "Result type " << i << " illegal!\n";
424 // Check that all operand types are legal.
425 for (unsigned i = 0, NumOps = I->getNumOperands(); i < NumOps; ++i)
426 if (!IgnoreNodeResults(I->getOperand(i).getNode()) &&
427 !isTypeLegal(I->getOperand(i).getValueType())) {
428 dbgs() << "Operand type " << i << " illegal!\n";
432 if (I->getNodeId() != Processed) {
433 if (I->getNodeId() == NewNode)
434 dbgs() << "New node not analyzed?\n";
435 else if (I->getNodeId() == Unanalyzed)
436 dbgs() << "Unanalyzed node not noticed?\n";
437 else if (I->getNodeId() > 0)
438 dbgs() << "Operand not processed?\n";
439 else if (I->getNodeId() == ReadyToProcess)
440 dbgs() << "Not added to worklist?\n";
445 I->dump(&DAG); dbgs() << "\n";
446 llvm_unreachable(nullptr);
454 /// AnalyzeNewNode - The specified node is the root of a subtree of potentially
455 /// new nodes. Correct any processed operands (this may change the node) and
456 /// calculate the NodeId. If the node itself changes to a processed node, it
457 /// is not remapped - the caller needs to take care of this.
458 /// Returns the potentially changed node.
459 SDNode *DAGTypeLegalizer::AnalyzeNewNode(SDNode *N) {
460 // If this was an existing node that is already done, we're done.
461 if (N->getNodeId() != NewNode && N->getNodeId() != Unanalyzed)
464 // Remove any stale map entries.
467 // Okay, we know that this node is new. Recursively walk all of its operands
468 // to see if they are new also. The depth of this walk is bounded by the size
469 // of the new tree that was constructed (usually 2-3 nodes), so we don't worry
470 // about revisiting of nodes.
472 // As we walk the operands, keep track of the number of nodes that are
473 // processed. If non-zero, this will become the new nodeid of this node.
474 // Operands may morph when they are analyzed. If so, the node will be
475 // updated after all operands have been analyzed. Since this is rare,
476 // the code tries to minimize overhead in the non-morphing case.
478 SmallVector<SDValue, 8> NewOps;
479 unsigned NumProcessed = 0;
480 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
481 SDValue OrigOp = N->getOperand(i);
484 AnalyzeNewValue(Op); // Op may morph.
486 if (Op.getNode()->getNodeId() == Processed)
489 if (!NewOps.empty()) {
490 // Some previous operand changed. Add this one to the list.
491 NewOps.push_back(Op);
492 } else if (Op != OrigOp) {
493 // This is the first operand to change - add all operands so far.
494 NewOps.append(N->op_begin(), N->op_begin() + i);
495 NewOps.push_back(Op);
499 // Some operands changed - update the node.
500 if (!NewOps.empty()) {
501 SDNode *M = DAG.UpdateNodeOperands(N, NewOps);
503 // The node morphed into a different node. Normally for this to happen
504 // the original node would have to be marked NewNode. However this can
505 // in theory momentarily not be the case while ReplaceValueWith is doing
506 // its stuff. Mark the original node NewNode to help sanity checking.
507 N->setNodeId(NewNode);
508 if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed)
509 // It morphed into a previously analyzed node - nothing more to do.
512 // It morphed into a different new node. Do the equivalent of passing
513 // it to AnalyzeNewNode: expunge it and calculate the NodeId. No need
514 // to remap the operands, since they are the same as the operands we
521 // Calculate the NodeId.
522 N->setNodeId(N->getNumOperands() - NumProcessed);
523 if (N->getNodeId() == ReadyToProcess)
524 Worklist.push_back(N);
529 /// AnalyzeNewValue - Call AnalyzeNewNode, updating the node in Val if needed.
530 /// If the node changes to a processed node, then remap it.
531 void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) {
532 Val.setNode(AnalyzeNewNode(Val.getNode()));
533 if (Val.getNode()->getNodeId() == Processed)
534 // We were passed a processed node, or it morphed into one - remap it.
538 /// ExpungeNode - If N has a bogus mapping in ReplacedValues, eliminate it.
539 /// This can occur when a node is deleted then reallocated as a new node -
540 /// the mapping in ReplacedValues applies to the deleted node, not the new
542 /// The only map that can have a deleted node as a source is ReplacedValues.
543 /// Other maps can have deleted nodes as targets, but since their looked-up
544 /// values are always immediately remapped using RemapValue, resulting in a
545 /// not-deleted node, this is harmless as long as ReplacedValues/RemapValue
546 /// always performs correct mappings. In order to keep the mapping correct,
547 /// ExpungeNode should be called on any new nodes *before* adding them as
548 /// either source or target to ReplacedValues (which typically means calling
549 /// Expunge when a new node is first seen, since it may no longer be marked
550 /// NewNode by the time it is added to ReplacedValues).
551 void DAGTypeLegalizer::ExpungeNode(SDNode *N) {
552 if (N->getNodeId() != NewNode)
555 // If N is not remapped by ReplacedValues then there is nothing to do.
557 for (i = 0, e = N->getNumValues(); i != e; ++i)
558 if (ReplacedValues.find(SDValue(N, i)) != ReplacedValues.end())
564 // Remove N from all maps - this is expensive but rare.
566 for (DenseMap<SDValue, SDValue>::iterator I = PromotedIntegers.begin(),
567 E = PromotedIntegers.end(); I != E; ++I) {
568 assert(I->first.getNode() != N);
569 RemapValue(I->second);
572 for (DenseMap<SDValue, SDValue>::iterator I = SoftenedFloats.begin(),
573 E = SoftenedFloats.end(); I != E; ++I) {
574 assert(I->first.getNode() != N);
575 RemapValue(I->second);
578 for (DenseMap<SDValue, SDValue>::iterator I = ScalarizedVectors.begin(),
579 E = ScalarizedVectors.end(); I != E; ++I) {
580 assert(I->first.getNode() != N);
581 RemapValue(I->second);
584 for (DenseMap<SDValue, SDValue>::iterator I = WidenedVectors.begin(),
585 E = WidenedVectors.end(); I != E; ++I) {
586 assert(I->first.getNode() != N);
587 RemapValue(I->second);
590 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator
591 I = ExpandedIntegers.begin(), E = ExpandedIntegers.end(); I != E; ++I){
592 assert(I->first.getNode() != N);
593 RemapValue(I->second.first);
594 RemapValue(I->second.second);
597 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator
598 I = ExpandedFloats.begin(), E = ExpandedFloats.end(); I != E; ++I) {
599 assert(I->first.getNode() != N);
600 RemapValue(I->second.first);
601 RemapValue(I->second.second);
604 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator
605 I = SplitVectors.begin(), E = SplitVectors.end(); I != E; ++I) {
606 assert(I->first.getNode() != N);
607 RemapValue(I->second.first);
608 RemapValue(I->second.second);
611 for (DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.begin(),
612 E = ReplacedValues.end(); I != E; ++I)
613 RemapValue(I->second);
615 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
616 ReplacedValues.erase(SDValue(N, i));
619 /// RemapValue - If the specified value was already legalized to another value,
620 /// replace it by that value.
621 void DAGTypeLegalizer::RemapValue(SDValue &N) {
622 DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(N);
623 if (I != ReplacedValues.end()) {
624 // Use path compression to speed up future lookups if values get multiply
625 // replaced with other values.
626 RemapValue(I->second);
629 // Note that it is possible to have N.getNode()->getNodeId() == NewNode at
630 // this point because it is possible for a node to be put in the map before
636 /// NodeUpdateListener - This class is a DAGUpdateListener that listens for
637 /// updates to nodes and recomputes their ready state.
638 class NodeUpdateListener : public SelectionDAG::DAGUpdateListener {
639 DAGTypeLegalizer &DTL;
640 SmallSetVector<SDNode*, 16> &NodesToAnalyze;
642 explicit NodeUpdateListener(DAGTypeLegalizer &dtl,
643 SmallSetVector<SDNode*, 16> &nta)
644 : SelectionDAG::DAGUpdateListener(dtl.getDAG()),
645 DTL(dtl), NodesToAnalyze(nta) {}
647 void NodeDeleted(SDNode *N, SDNode *E) override {
648 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
649 N->getNodeId() != DAGTypeLegalizer::Processed &&
650 "Invalid node ID for RAUW deletion!");
651 // It is possible, though rare, for the deleted node N to occur as a
652 // target in a map, so note the replacement N -> E in ReplacedValues.
653 assert(E && "Node not replaced?");
654 DTL.NoteDeletion(N, E);
656 // In theory the deleted node could also have been scheduled for analysis.
657 // So remove it from the set of nodes which will be analyzed.
658 NodesToAnalyze.remove(N);
660 // In general nothing needs to be done for E, since it didn't change but
661 // only gained new uses. However N -> E was just added to ReplacedValues,
662 // and the result of a ReplacedValues mapping is not allowed to be marked
663 // NewNode. So if E is marked NewNode, then it needs to be analyzed.
664 if (E->getNodeId() == DAGTypeLegalizer::NewNode)
665 NodesToAnalyze.insert(E);
668 void NodeUpdated(SDNode *N) override {
669 // Node updates can mean pretty much anything. It is possible that an
670 // operand was set to something already processed (f.e.) in which case
671 // this node could become ready. Recompute its flags.
672 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
673 N->getNodeId() != DAGTypeLegalizer::Processed &&
674 "Invalid node ID for RAUW deletion!");
675 N->setNodeId(DAGTypeLegalizer::NewNode);
676 NodesToAnalyze.insert(N);
682 /// ReplaceValueWith - The specified value was legalized to the specified other
683 /// value. Update the DAG and NodeIds replacing any uses of From to use To
685 void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) {
686 assert(From.getNode() != To.getNode() && "Potential legalization loop!");
688 // If expansion produced new nodes, make sure they are properly marked.
689 ExpungeNode(From.getNode());
690 AnalyzeNewValue(To); // Expunges To.
692 // Anything that used the old node should now use the new one. Note that this
693 // can potentially cause recursive merging.
694 SmallSetVector<SDNode*, 16> NodesToAnalyze;
695 NodeUpdateListener NUL(*this, NodesToAnalyze);
697 DAG.ReplaceAllUsesOfValueWith(From, To);
699 // The old node may still be present in a map like ExpandedIntegers or
700 // PromotedIntegers. Inform maps about the replacement.
701 ReplacedValues[From] = To;
703 // Process the list of nodes that need to be reanalyzed.
704 while (!NodesToAnalyze.empty()) {
705 SDNode *N = NodesToAnalyze.back();
706 NodesToAnalyze.pop_back();
707 if (N->getNodeId() != DAGTypeLegalizer::NewNode)
708 // The node was analyzed while reanalyzing an earlier node - it is safe
709 // to skip. Note that this is not a morphing node - otherwise it would
710 // still be marked NewNode.
713 // Analyze the node's operands and recalculate the node ID.
714 SDNode *M = AnalyzeNewNode(N);
716 // The node morphed into a different node. Make everyone use the new
718 assert(M->getNodeId() != NewNode && "Analysis resulted in NewNode!");
719 assert(N->getNumValues() == M->getNumValues() &&
720 "Node morphing changed the number of results!");
721 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) {
722 SDValue OldVal(N, i);
723 SDValue NewVal(M, i);
724 if (M->getNodeId() == Processed)
726 DAG.ReplaceAllUsesOfValueWith(OldVal, NewVal);
727 // OldVal may be a target of the ReplacedValues map which was marked
728 // NewNode to force reanalysis because it was updated. Ensure that
729 // anything that ReplacedValues mapped to OldVal will now be mapped
730 // all the way to NewVal.
731 ReplacedValues[OldVal] = NewVal;
733 // The original node continues to exist in the DAG, marked NewNode.
736 // When recursively update nodes with new nodes, it is possible to have
737 // new uses of From due to CSE. If this happens, replace the new uses of
739 } while (!From.use_empty());
742 void DAGTypeLegalizer::SetPromotedInteger(SDValue Op, SDValue Result) {
743 assert(Result.getValueType() ==
744 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
745 "Invalid type for promoted integer");
746 AnalyzeNewValue(Result);
748 SDValue &OpEntry = PromotedIntegers[Op];
749 assert(!OpEntry.getNode() && "Node is already promoted!");
753 void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) {
754 assert(Result.getValueType() ==
755 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
756 "Invalid type for softened float");
757 AnalyzeNewValue(Result);
759 SDValue &OpEntry = SoftenedFloats[Op];
760 assert(!OpEntry.getNode() && "Node is already converted to integer!");
764 void DAGTypeLegalizer::SetPromotedFloat(SDValue Op, SDValue Result) {
765 assert(Result.getValueType() ==
766 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
767 "Invalid type for promoted float");
768 AnalyzeNewValue(Result);
770 SDValue &OpEntry = PromotedFloats[Op];
771 assert(!OpEntry.getNode() && "Node is already promoted!");
775 void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) {
776 // Note that in some cases vector operation operands may be greater than
777 // the vector element type. For example BUILD_VECTOR of type <1 x i1> with
778 // a constant i8 operand.
779 assert(Result.getValueType().getSizeInBits() >=
780 Op.getValueType().getVectorElementType().getSizeInBits() &&
781 "Invalid type for scalarized vector");
782 AnalyzeNewValue(Result);
784 SDValue &OpEntry = ScalarizedVectors[Op];
785 assert(!OpEntry.getNode() && "Node is already scalarized!");
789 void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo,
791 std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op];
792 RemapValue(Entry.first);
793 RemapValue(Entry.second);
794 assert(Entry.first.getNode() && "Operand isn't expanded");
799 void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo,
801 assert(Lo.getValueType() ==
802 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
803 Hi.getValueType() == Lo.getValueType() &&
804 "Invalid type for expanded integer");
805 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
809 // Remember that this is the result of the node.
810 std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op];
811 assert(!Entry.first.getNode() && "Node already expanded");
816 void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo,
818 std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op];
819 RemapValue(Entry.first);
820 RemapValue(Entry.second);
821 assert(Entry.first.getNode() && "Operand isn't expanded");
826 void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo,
828 assert(Lo.getValueType() ==
829 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
830 Hi.getValueType() == Lo.getValueType() &&
831 "Invalid type for expanded float");
832 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
836 // Remember that this is the result of the node.
837 std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op];
838 assert(!Entry.first.getNode() && "Node already expanded");
843 void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo,
845 std::pair<SDValue, SDValue> &Entry = SplitVectors[Op];
846 RemapValue(Entry.first);
847 RemapValue(Entry.second);
848 assert(Entry.first.getNode() && "Operand isn't split");
853 void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo,
855 assert(Lo.getValueType().getVectorElementType() ==
856 Op.getValueType().getVectorElementType() &&
857 2*Lo.getValueType().getVectorNumElements() ==
858 Op.getValueType().getVectorNumElements() &&
859 Hi.getValueType() == Lo.getValueType() &&
860 "Invalid type for split vector");
861 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant.
865 // Remember that this is the result of the node.
866 std::pair<SDValue, SDValue> &Entry = SplitVectors[Op];
867 assert(!Entry.first.getNode() && "Node already split");
872 void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) {
873 assert(Result.getValueType() ==
874 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) &&
875 "Invalid type for widened vector");
876 AnalyzeNewValue(Result);
878 SDValue &OpEntry = WidenedVectors[Op];
879 assert(!OpEntry.getNode() && "Node already widened!");
884 //===----------------------------------------------------------------------===//
886 //===----------------------------------------------------------------------===//
888 /// BitConvertToInteger - Convert to an integer of the same size.
889 SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) {
890 unsigned BitWidth = Op.getValueType().getSizeInBits();
891 return DAG.getNode(ISD::BITCAST, SDLoc(Op),
892 EVT::getIntegerVT(*DAG.getContext(), BitWidth), Op);
895 /// BitConvertVectorToIntegerVector - Convert to a vector of integers of the
897 SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) {
898 assert(Op.getValueType().isVector() && "Only applies to vectors!");
899 unsigned EltWidth = Op.getValueType().getVectorElementType().getSizeInBits();
900 EVT EltNVT = EVT::getIntegerVT(*DAG.getContext(), EltWidth);
901 unsigned NumElts = Op.getValueType().getVectorNumElements();
902 return DAG.getNode(ISD::BITCAST, SDLoc(Op),
903 EVT::getVectorVT(*DAG.getContext(), EltNVT, NumElts), Op);
906 SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op,
909 // Create the stack frame object. Make sure it is aligned for both
910 // the source and destination types.
911 SDValue StackPtr = DAG.CreateStackTemporary(Op.getValueType(), DestVT);
912 // Emit a store to the stack slot.
913 SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Op, StackPtr,
914 MachinePointerInfo(), false, false, 0);
915 // Result is a load from the stack slot.
916 return DAG.getLoad(DestVT, dl, Store, StackPtr, MachinePointerInfo(),
917 false, false, false, 0);
920 /// CustomLowerNode - Replace the node's results with custom code provided
921 /// by the target and return "true", or do nothing and return "false".
922 /// The last parameter is FALSE if we are dealing with a node with legal
923 /// result types and illegal operand. The second parameter denotes the type of
924 /// illegal OperandNo in that case.
925 /// The last parameter being TRUE means we are dealing with a
926 /// node with illegal result types. The second parameter denotes the type of
927 /// illegal ResNo in that case.
928 bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) {
929 // See if the target wants to custom lower this node.
930 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom)
933 SmallVector<SDValue, 8> Results;
935 TLI.ReplaceNodeResults(N, Results, DAG);
937 TLI.LowerOperationWrapper(N, Results, DAG);
940 // The target didn't want to custom lower it after all.
943 // When called from DAGTypeLegalizer::ExpandIntegerResult, we might need to
944 // provide the same kind of custom splitting behavior.
945 if (Results.size() == N->getNumValues() + 1 && LegalizeResult) {
946 // We've legalized a return type by splitting it. If there is a chain,
948 SetExpandedInteger(SDValue(N, 0), Results[0], Results[1]);
949 if (N->getNumValues() > 1)
950 ReplaceValueWith(SDValue(N, 1), Results[2]);
954 // Make everything that once used N's values now use those in Results instead.
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 ReplaceValueWith(SDValue(N, i), Results[i]);
964 /// CustomWidenLowerNode - Widen the node's results with custom code provided
965 /// by the target and return "true", or do nothing and return "false".
966 bool DAGTypeLegalizer::CustomWidenLowerNode(SDNode *N, EVT VT) {
967 // See if the target wants to custom lower this node.
968 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom)
971 SmallVector<SDValue, 8> Results;
972 TLI.ReplaceNodeResults(N, Results, DAG);
975 // The target didn't want to custom widen lower its result after all.
978 // Update the widening map.
979 assert(Results.size() == N->getNumValues() &&
980 "Custom lowering returned the wrong number of results!");
981 for (unsigned i = 0, e = Results.size(); i != e; ++i)
982 SetWidenedVector(SDValue(N, i), Results[i]);
986 SDValue DAGTypeLegalizer::DisintegrateMERGE_VALUES(SDNode *N, unsigned ResNo) {
987 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i)
989 ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i)));
990 return SDValue(N->getOperand(ResNo));
993 /// GetPairElements - Use ISD::EXTRACT_ELEMENT nodes to extract the low and
994 /// high parts of the given value.
995 void DAGTypeLegalizer::GetPairElements(SDValue Pair,
996 SDValue &Lo, SDValue &Hi) {
998 EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), Pair.getValueType());
999 Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair,
1000 DAG.getIntPtrConstant(0, dl));
1001 Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair,
1002 DAG.getIntPtrConstant(1, dl));
1005 SDValue DAGTypeLegalizer::GetVectorElementPointer(SDValue VecPtr, EVT EltVT,
1008 // Make sure the index type is big enough to compute in.
1009 Index = DAG.getZExtOrTrunc(Index, dl, TLI.getPointerTy());
1011 // Calculate the element offset and add it to the pointer.
1012 unsigned EltSize = EltVT.getSizeInBits() / 8; // FIXME: should be ABI size.
1014 Index = DAG.getNode(ISD::MUL, dl, Index.getValueType(), Index,
1015 DAG.getConstant(EltSize, dl, Index.getValueType()));
1016 return DAG.getNode(ISD::ADD, dl, Index.getValueType(), Index, VecPtr);
1019 /// JoinIntegers - Build an integer with low bits Lo and high bits Hi.
1020 SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) {
1021 // Arbitrarily use dlHi for result SDLoc
1024 EVT LVT = Lo.getValueType();
1025 EVT HVT = Hi.getValueType();
1026 EVT NVT = EVT::getIntegerVT(*DAG.getContext(),
1027 LVT.getSizeInBits() + HVT.getSizeInBits());
1029 Lo = DAG.getNode(ISD::ZERO_EXTEND, dlLo, NVT, Lo);
1030 Hi = DAG.getNode(ISD::ANY_EXTEND, dlHi, NVT, Hi);
1031 Hi = DAG.getNode(ISD::SHL, dlHi, NVT, Hi,
1032 DAG.getConstant(LVT.getSizeInBits(), dlHi,
1033 TLI.getPointerTy()));
1034 return DAG.getNode(ISD::OR, dlHi, NVT, Lo, Hi);
1037 /// LibCallify - Convert the node into a libcall with the same prototype.
1038 SDValue DAGTypeLegalizer::LibCallify(RTLIB::Libcall LC, SDNode *N,
1040 unsigned NumOps = N->getNumOperands();
1043 return TLI.makeLibCall(DAG, LC, N->getValueType(0), nullptr, 0, isSigned,
1045 } else if (NumOps == 1) {
1046 SDValue Op = N->getOperand(0);
1047 return TLI.makeLibCall(DAG, LC, N->getValueType(0), &Op, 1, isSigned,
1049 } else if (NumOps == 2) {
1050 SDValue Ops[2] = { N->getOperand(0), N->getOperand(1) };
1051 return TLI.makeLibCall(DAG, LC, N->getValueType(0), Ops, 2, isSigned,
1054 SmallVector<SDValue, 8> Ops(NumOps);
1055 for (unsigned i = 0; i < NumOps; ++i)
1056 Ops[i] = N->getOperand(i);
1058 return TLI.makeLibCall(DAG, LC, N->getValueType(0),
1059 &Ops[0], NumOps, isSigned, dl).first;
1062 // ExpandChainLibCall - Expand a node into a call to a libcall. Similar to
1063 // ExpandLibCall except that the first operand is the in-chain.
1064 std::pair<SDValue, SDValue>
1065 DAGTypeLegalizer::ExpandChainLibCall(RTLIB::Libcall LC,
1068 SDValue InChain = Node->getOperand(0);
1070 TargetLowering::ArgListTy Args;
1071 TargetLowering::ArgListEntry Entry;
1072 for (unsigned i = 1, e = Node->getNumOperands(); i != e; ++i) {
1073 EVT ArgVT = Node->getOperand(i).getValueType();
1074 Type *ArgTy = ArgVT.getTypeForEVT(*DAG.getContext());
1075 Entry.Node = Node->getOperand(i);
1077 Entry.isSExt = isSigned;
1078 Entry.isZExt = !isSigned;
1079 Args.push_back(Entry);
1081 SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC),
1082 TLI.getPointerTy());
1084 Type *RetTy = Node->getValueType(0).getTypeForEVT(*DAG.getContext());
1086 TargetLowering::CallLoweringInfo CLI(DAG);
1087 CLI.setDebugLoc(SDLoc(Node)).setChain(InChain)
1088 .setCallee(TLI.getLibcallCallingConv(LC), RetTy, Callee, std::move(Args), 0)
1089 .setSExtResult(isSigned).setZExtResult(!isSigned);
1091 std::pair<SDValue, SDValue> CallInfo = TLI.LowerCallTo(CLI);
1096 /// PromoteTargetBoolean - Promote the given target boolean to a target boolean
1097 /// of the given type. A target boolean is an integer value, not necessarily of
1098 /// type i1, the bits of which conform to getBooleanContents.
1100 /// ValVT is the type of values that produced the boolean.
1101 SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT ValVT) {
1103 EVT BoolVT = getSetCCResultType(ValVT);
1104 ISD::NodeType ExtendCode =
1105 TargetLowering::getExtendForContent(TLI.getBooleanContents(ValVT));
1106 return DAG.getNode(ExtendCode, dl, BoolVT, Bool);
1109 /// SplitInteger - Return the lower LoVT bits of Op in Lo and the upper HiVT
1111 void DAGTypeLegalizer::SplitInteger(SDValue Op,
1113 SDValue &Lo, SDValue &Hi) {
1115 assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() ==
1116 Op.getValueType().getSizeInBits() && "Invalid integer splitting!");
1117 Lo = DAG.getNode(ISD::TRUNCATE, dl, LoVT, Op);
1118 Hi = DAG.getNode(ISD::SRL, dl, Op.getValueType(), Op,
1119 DAG.getConstant(LoVT.getSizeInBits(), dl,
1120 TLI.getPointerTy()));
1121 Hi = DAG.getNode(ISD::TRUNCATE, dl, HiVT, Hi);
1124 /// SplitInteger - Return the lower and upper halves of Op's bits in a value
1125 /// type half the size of Op's.
1126 void DAGTypeLegalizer::SplitInteger(SDValue Op,
1127 SDValue &Lo, SDValue &Hi) {
1128 EVT HalfVT = EVT::getIntegerVT(*DAG.getContext(),
1129 Op.getValueType().getSizeInBits()/2);
1130 SplitInteger(Op, HalfVT, HalfVT, Lo, Hi);
1134 //===----------------------------------------------------------------------===//
1136 //===----------------------------------------------------------------------===//
1138 /// LegalizeTypes - This transforms the SelectionDAG into a SelectionDAG that
1139 /// only uses types natively supported by the target. Returns "true" if it made
1142 /// Note that this is an involved process that may invalidate pointers into
1144 bool SelectionDAG::LegalizeTypes() {
1145 return DAGTypeLegalizer(*this).run();