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" 21 using namespace llvm; 22 23 #define DEBUG_TYPE "legalize-types" 24 25 static cl::opt<bool> 26 EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden); 27 28 /// Do extensive, expensive, basic correctness checking. 29 void 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(&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(Res); 84 85 unsigned Mapped = 0; 86 if (ResId) { 87 auto I = ReplacedValues.find(ResId); 88 if (I != ReplacedValues.end()) { 89 Mapped |= 1; 90 // Check that remapped values are only used by nodes marked NewNode. 91 for (SDUse &U : Node.uses()) 92 if (U.getResNo() == i) 93 assert(U.getUser()->getNodeId() == NewNode && 94 "Remapped value has non-trivial use!"); 95 96 // Check that the final result of applying ReplacedValues is not 97 // marked NewNode. 98 auto NewValId = I->second; 99 I = ReplacedValues.find(NewValId); 100 while (I != ReplacedValues.end()) { 101 NewValId = I->second; 102 I = ReplacedValues.find(NewValId); 103 } 104 SDValue NewVal = getSDValue(NewValId); 105 (void)NewVal; 106 assert(NewVal.getNode()->getNodeId() != NewNode && 107 "ReplacedValues maps to a new node!"); 108 } 109 if (PromotedIntegers.count(ResId)) 110 Mapped |= 2; 111 if (SoftenedFloats.count(ResId)) 112 Mapped |= 4; 113 if (ScalarizedVectors.count(ResId)) 114 Mapped |= 8; 115 if (ExpandedIntegers.count(ResId)) 116 Mapped |= 16; 117 if (ExpandedFloats.count(ResId)) 118 Mapped |= 32; 119 if (SplitVectors.count(ResId)) 120 Mapped |= 64; 121 if (WidenedVectors.count(ResId)) 122 Mapped |= 128; 123 if (PromotedFloats.count(ResId)) 124 Mapped |= 256; 125 if (SoftPromotedHalfs.count(ResId)) 126 Mapped |= 512; 127 } 128 129 if (Node.getNodeId() != Processed) { 130 // Since we allow ReplacedValues to map deleted nodes, it may map nodes 131 // marked NewNode too, since a deleted node may have been reallocated as 132 // another node that has not been seen by the LegalizeTypes machinery. 133 if ((Node.getNodeId() == NewNode && Mapped > 1) || 134 (Node.getNodeId() != NewNode && Mapped != 0)) { 135 dbgs() << "Unprocessed value in a map!"; 136 Failed = true; 137 } 138 } else if (isTypeLegal(Res.getValueType()) || IgnoreNodeResults(&Node)) { 139 if (Mapped > 1) { 140 dbgs() << "Value with legal type was transformed!"; 141 Failed = true; 142 } 143 } else { 144 if (Mapped == 0) { 145 SDValue NodeById = IdToValueMap.lookup(ResId); 146 // It is possible the node has been remapped to another node and had 147 // its Id updated in the Value to Id table. The node it remapped to 148 // may not have been processed yet. Look up the Id in the Id to Value 149 // table and re-check the Processed state. If the node hasn't been 150 // remapped we'll get the same state as we got earlier. 151 if (NodeById->getNodeId() == Processed) { 152 dbgs() << "Processed value not in any map!"; 153 Failed = true; 154 } 155 } else if (Mapped & (Mapped - 1)) { 156 dbgs() << "Value in multiple maps!"; 157 Failed = true; 158 } 159 } 160 161 if (Failed) { 162 if (Mapped & 1) 163 dbgs() << " ReplacedValues"; 164 if (Mapped & 2) 165 dbgs() << " PromotedIntegers"; 166 if (Mapped & 4) 167 dbgs() << " SoftenedFloats"; 168 if (Mapped & 8) 169 dbgs() << " ScalarizedVectors"; 170 if (Mapped & 16) 171 dbgs() << " ExpandedIntegers"; 172 if (Mapped & 32) 173 dbgs() << " ExpandedFloats"; 174 if (Mapped & 64) 175 dbgs() << " SplitVectors"; 176 if (Mapped & 128) 177 dbgs() << " WidenedVectors"; 178 if (Mapped & 256) 179 dbgs() << " PromotedFloats"; 180 if (Mapped & 512) 181 dbgs() << " SoftPromoteHalfs"; 182 dbgs() << "\n"; 183 llvm_unreachable(nullptr); 184 } 185 } 186 } 187 188 #ifndef NDEBUG 189 // Checked that NewNodes are only used by other NewNodes. 190 for (SDNode *N : NewNodes) { 191 for (SDNode *U : N->users()) 192 assert(U->getNodeId() == NewNode && "NewNode used by non-NewNode!"); 193 } 194 #endif 195 } 196 197 /// This is the main entry point for the type legalizer. This does a top-down 198 /// traversal of the dag, legalizing types as it goes. Returns "true" if it made 199 /// any changes. 200 bool DAGTypeLegalizer::run() { 201 bool Changed = false; 202 203 // Create a dummy node (which is not added to allnodes), that adds a reference 204 // to the root node, preventing it from being deleted, and tracking any 205 // changes of the root. 206 HandleSDNode Dummy(DAG.getRoot()); 207 Dummy.setNodeId(Unanalyzed); 208 209 // The root of the dag may dangle to deleted nodes until the type legalizer is 210 // done. Set it to null to avoid confusion. 211 DAG.setRoot(SDValue()); 212 213 // Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess' 214 // (and remembering them) if they are leaves and assigning 'Unanalyzed' if 215 // non-leaves. 216 for (SDNode &Node : DAG.allnodes()) { 217 if (Node.getNumOperands() == 0) { 218 Node.setNodeId(ReadyToProcess); 219 Worklist.push_back(&Node); 220 } else { 221 Node.setNodeId(Unanalyzed); 222 } 223 } 224 225 // Now that we have a set of nodes to process, handle them all. 226 while (!Worklist.empty()) { 227 #ifndef EXPENSIVE_CHECKS 228 if (EnableExpensiveChecks) 229 #endif 230 PerformExpensiveChecks(); 231 232 SDNode *N = Worklist.pop_back_val(); 233 assert(N->getNodeId() == ReadyToProcess && 234 "Node should be ready if on worklist!"); 235 236 LLVM_DEBUG(dbgs() << "\nLegalizing node: "; N->dump(&DAG)); 237 if (IgnoreNodeResults(N)) { 238 LLVM_DEBUG(dbgs() << "Ignoring node results\n"); 239 goto ScanOperands; 240 } 241 242 // Scan the values produced by the node, checking to see if any result 243 // types are illegal. 244 for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) { 245 EVT ResultVT = N->getValueType(i); 246 LLVM_DEBUG(dbgs() << "Analyzing result type: " << ResultVT << "\n"); 247 switch (getTypeAction(ResultVT)) { 248 case TargetLowering::TypeLegal: 249 LLVM_DEBUG(dbgs() << "Legal result type\n"); 250 break; 251 case TargetLowering::TypeScalarizeScalableVector: 252 report_fatal_error( 253 "Scalarization of scalable vectors is not supported."); 254 // The following calls must take care of *all* of the node's results, 255 // not just the illegal result they were passed (this includes results 256 // with a legal type). Results can be remapped using ReplaceValueWith, 257 // or their promoted/expanded/etc values registered in PromotedIntegers, 258 // ExpandedIntegers etc. 259 case TargetLowering::TypePromoteInteger: 260 PromoteIntegerResult(N, i); 261 Changed = true; 262 goto NodeDone; 263 case TargetLowering::TypeExpandInteger: 264 ExpandIntegerResult(N, i); 265 Changed = true; 266 goto NodeDone; 267 case TargetLowering::TypeSoftenFloat: 268 SoftenFloatResult(N, i); 269 Changed = true; 270 goto NodeDone; 271 case TargetLowering::TypeExpandFloat: 272 ExpandFloatResult(N, i); 273 Changed = true; 274 goto NodeDone; 275 case TargetLowering::TypeScalarizeVector: 276 ScalarizeVectorResult(N, i); 277 Changed = true; 278 goto NodeDone; 279 case TargetLowering::TypeSplitVector: 280 SplitVectorResult(N, i); 281 Changed = true; 282 goto NodeDone; 283 case TargetLowering::TypeWidenVector: 284 WidenVectorResult(N, i); 285 Changed = true; 286 goto NodeDone; 287 case TargetLowering::TypePromoteFloat: 288 PromoteFloatResult(N, i); 289 Changed = true; 290 goto NodeDone; 291 case TargetLowering::TypeSoftPromoteHalf: 292 SoftPromoteHalfResult(N, i); 293 Changed = true; 294 goto NodeDone; 295 } 296 } 297 298 ScanOperands: 299 // Scan the operand list for the node, handling any nodes with operands that 300 // are illegal. 301 { 302 unsigned NumOperands = N->getNumOperands(); 303 bool NeedsReanalyzing = false; 304 unsigned i; 305 for (i = 0; i != NumOperands; ++i) { 306 if (IgnoreNodeResults(N->getOperand(i).getNode())) 307 continue; 308 309 const auto &Op = N->getOperand(i); 310 LLVM_DEBUG(dbgs() << "Analyzing operand: "; Op.dump(&DAG)); 311 EVT OpVT = Op.getValueType(); 312 switch (getTypeAction(OpVT)) { 313 case TargetLowering::TypeLegal: 314 LLVM_DEBUG(dbgs() << "Legal operand\n"); 315 continue; 316 case TargetLowering::TypeScalarizeScalableVector: 317 report_fatal_error( 318 "Scalarization of scalable vectors is not supported."); 319 // The following calls must either replace all of the node's results 320 // using ReplaceValueWith, and return "false"; or update the node's 321 // operands in place, and return "true". 322 case TargetLowering::TypePromoteInteger: 323 NeedsReanalyzing = PromoteIntegerOperand(N, i); 324 Changed = true; 325 break; 326 case TargetLowering::TypeExpandInteger: 327 NeedsReanalyzing = ExpandIntegerOperand(N, i); 328 Changed = true; 329 break; 330 case TargetLowering::TypeSoftenFloat: 331 NeedsReanalyzing = SoftenFloatOperand(N, i); 332 Changed = true; 333 break; 334 case TargetLowering::TypeExpandFloat: 335 NeedsReanalyzing = ExpandFloatOperand(N, i); 336 Changed = true; 337 break; 338 case TargetLowering::TypeScalarizeVector: 339 NeedsReanalyzing = ScalarizeVectorOperand(N, i); 340 Changed = true; 341 break; 342 case TargetLowering::TypeSplitVector: 343 NeedsReanalyzing = SplitVectorOperand(N, i); 344 Changed = true; 345 break; 346 case TargetLowering::TypeWidenVector: 347 NeedsReanalyzing = WidenVectorOperand(N, i); 348 Changed = true; 349 break; 350 case TargetLowering::TypePromoteFloat: 351 NeedsReanalyzing = PromoteFloatOperand(N, i); 352 Changed = true; 353 break; 354 case TargetLowering::TypeSoftPromoteHalf: 355 NeedsReanalyzing = SoftPromoteHalfOperand(N, i); 356 Changed = true; 357 break; 358 } 359 break; 360 } 361 362 // The sub-method updated N in place. Check to see if any operands are new, 363 // and if so, mark them. If the node needs revisiting, don't add all users 364 // to the worklist etc. 365 if (NeedsReanalyzing) { 366 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 367 368 N->setNodeId(NewNode); 369 // Recompute the NodeId and correct processed operands, adding the node to 370 // the worklist if ready. 371 SDNode *M = AnalyzeNewNode(N); 372 if (M == N) 373 // The node didn't morph - nothing special to do, it will be revisited. 374 continue; 375 376 // The node morphed - this is equivalent to legalizing by replacing every 377 // value of N with the corresponding value of M. So do that now. 378 assert(N->getNumValues() == M->getNumValues() && 379 "Node morphing changed the number of results!"); 380 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 381 // Replacing the value takes care of remapping the new value. 382 ReplaceValueWith(SDValue(N, i), SDValue(M, i)); 383 assert(N->getNodeId() == NewNode && "Unexpected node state!"); 384 // The node continues to live on as part of the NewNode fungus that 385 // grows on top of the useful nodes. Nothing more needs to be done 386 // with it - move on to the next node. 387 continue; 388 } 389 390 if (i == NumOperands) { 391 LLVM_DEBUG(dbgs() << "Legally typed node: "; N->dump(&DAG)); 392 } 393 } 394 NodeDone: 395 396 // If we reach here, the node was processed, potentially creating new nodes. 397 // Mark it as processed and add its users to the worklist as appropriate. 398 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 399 N->setNodeId(Processed); 400 401 for (SDNode *User : N->users()) { 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. 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 basic correctness 542 // checking. 543 N->setNodeId(NewNode); 544 if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed) 545 // It morphed into a previously analyzed node - nothing more to do. 546 return M; 547 548 // It morphed into a different new node. Do the equivalent of passing 549 // it to AnalyzeNewNode: expunge it and calculate the NodeId. No need 550 // to remap the operands, since they are the same as the operands we 551 // remapped above. 552 N = M; 553 } 554 } 555 556 // Calculate the NodeId. 557 N->setNodeId(N->getNumOperands() - NumProcessed); 558 if (N->getNodeId() == ReadyToProcess) 559 Worklist.push_back(N); 560 561 return N; 562 } 563 564 /// Call AnalyzeNewNode, updating the node in Val if needed. 565 /// If the node changes to a processed node, then remap it. 566 void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) { 567 Val.setNode(AnalyzeNewNode(Val.getNode())); 568 if (Val.getNode()->getNodeId() == Processed) 569 // We were passed a processed node, or it morphed into one - remap it. 570 RemapValue(Val); 571 } 572 573 /// If the specified value was already legalized to another value, 574 /// replace it by that value. 575 void DAGTypeLegalizer::RemapValue(SDValue &V) { 576 auto Id = getTableId(V); 577 V = getSDValue(Id); 578 } 579 580 void DAGTypeLegalizer::RemapId(TableId &Id) { 581 auto I = ReplacedValues.find(Id); 582 if (I != ReplacedValues.end()) { 583 assert(Id != I->second && "Id is mapped to itself."); 584 // Use path compression to speed up future lookups if values get multiply 585 // replaced with other values. 586 RemapId(I->second); 587 Id = I->second; 588 589 // Note that N = IdToValueMap[Id] it is possible to have 590 // N.getNode()->getNodeId() == NewNode at this point because it is possible 591 // for a node to be put in the map before being processed. 592 } 593 } 594 595 namespace { 596 /// This class is a DAGUpdateListener that listens for updates to nodes and 597 /// recomputes their ready state. 598 class NodeUpdateListener : public SelectionDAG::DAGUpdateListener { 599 DAGTypeLegalizer &DTL; 600 SmallSetVector<SDNode*, 16> &NodesToAnalyze; 601 public: 602 explicit NodeUpdateListener(DAGTypeLegalizer &dtl, 603 SmallSetVector<SDNode*, 16> &nta) 604 : SelectionDAG::DAGUpdateListener(dtl.getDAG()), 605 DTL(dtl), NodesToAnalyze(nta) {} 606 607 void NodeDeleted(SDNode *N, SDNode *E) override { 608 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 609 N->getNodeId() != DAGTypeLegalizer::Processed && 610 "Invalid node ID for RAUW deletion!"); 611 // It is possible, though rare, for the deleted node N to occur as a 612 // target in a map, so note the replacement N -> E in ReplacedValues. 613 assert(E && "Node not replaced?"); 614 DTL.NoteDeletion(N, E); 615 616 // In theory the deleted node could also have been scheduled for analysis. 617 // So remove it from the set of nodes which will be analyzed. 618 NodesToAnalyze.remove(N); 619 620 // In general nothing needs to be done for E, since it didn't change but 621 // only gained new uses. However N -> E was just added to ReplacedValues, 622 // and the result of a ReplacedValues mapping is not allowed to be marked 623 // NewNode. So if E is marked NewNode, then it needs to be analyzed. 624 if (E->getNodeId() == DAGTypeLegalizer::NewNode) 625 NodesToAnalyze.insert(E); 626 } 627 628 void NodeUpdated(SDNode *N) override { 629 // Node updates can mean pretty much anything. It is possible that an 630 // operand was set to something already processed (f.e.) in which case 631 // this node could become ready. Recompute its flags. 632 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 633 N->getNodeId() != DAGTypeLegalizer::Processed && 634 "Invalid node ID for RAUW deletion!"); 635 N->setNodeId(DAGTypeLegalizer::NewNode); 636 NodesToAnalyze.insert(N); 637 } 638 }; 639 } 640 641 642 /// The specified value was legalized to the specified other value. 643 /// Update the DAG and NodeIds replacing any uses of From to use To instead. 644 void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) { 645 assert(From.getNode() != To.getNode() && "Potential legalization loop!"); 646 647 // If expansion produced new nodes, make sure they are properly marked. 648 AnalyzeNewValue(To); 649 650 // Anything that used the old node should now use the new one. Note that this 651 // can potentially cause recursive merging. 652 SmallSetVector<SDNode*, 16> NodesToAnalyze; 653 NodeUpdateListener NUL(*this, NodesToAnalyze); 654 do { 655 656 // The old node may be present in a map like ExpandedIntegers or 657 // PromotedIntegers. Inform maps about the replacement. 658 auto FromId = getTableId(From); 659 auto ToId = getTableId(To); 660 661 if (FromId != ToId) 662 ReplacedValues[FromId] = ToId; 663 DAG.ReplaceAllUsesOfValueWith(From, To); 664 665 // Process the list of nodes that need to be reanalyzed. 666 while (!NodesToAnalyze.empty()) { 667 SDNode *N = NodesToAnalyze.pop_back_val(); 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 } 705 706 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); 715 716 DAG.transferDbgValues(Op, Result); 717 } 718 719 void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) { 720 #ifndef NDEBUG 721 EVT VT = Result.getValueType(); 722 LLVMContext &Ctx = *DAG.getContext(); 723 assert((VT == EVT::getIntegerVT(Ctx, 80) || 724 VT == TLI.getTypeToTransformTo(Ctx, Op.getValueType())) && 725 "Invalid type for softened float"); 726 #endif 727 AnalyzeNewValue(Result); 728 729 auto &OpIdEntry = SoftenedFloats[getTableId(Op)]; 730 assert((OpIdEntry == 0) && "Node is already converted to integer!"); 731 OpIdEntry = getTableId(Result); 732 } 733 734 void DAGTypeLegalizer::SetPromotedFloat(SDValue Op, SDValue Result) { 735 assert(Result.getValueType() == 736 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 737 "Invalid type for promoted float"); 738 AnalyzeNewValue(Result); 739 740 auto &OpIdEntry = PromotedFloats[getTableId(Op)]; 741 assert((OpIdEntry == 0) && "Node is already promoted!"); 742 OpIdEntry = getTableId(Result); 743 } 744 745 void DAGTypeLegalizer::SetSoftPromotedHalf(SDValue Op, SDValue Result) { 746 assert(Result.getValueType() == MVT::i16 && 747 "Invalid type for soft-promoted half"); 748 AnalyzeNewValue(Result); 749 750 auto &OpIdEntry = SoftPromotedHalfs[getTableId(Op)]; 751 assert((OpIdEntry == 0) && "Node is already promoted!"); 752 OpIdEntry = getTableId(Result); 753 } 754 755 void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) { 756 // Note that in some cases vector operation operands may be greater than 757 // the vector element type. For example BUILD_VECTOR of type <1 x i1> with 758 // a constant i8 operand. 759 760 // We don't currently support the scalarization of scalable vector types. 761 assert(Result.getValueSizeInBits().getFixedValue() >= 762 Op.getScalarValueSizeInBits() && 763 "Invalid type for scalarized vector"); 764 AnalyzeNewValue(Result); 765 766 auto &OpIdEntry = ScalarizedVectors[getTableId(Op)]; 767 assert((OpIdEntry == 0) && "Node is already scalarized!"); 768 OpIdEntry = getTableId(Result); 769 } 770 771 void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo, 772 SDValue &Hi) { 773 std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(Op)]; 774 assert((Entry.first != 0) && "Operand isn't expanded"); 775 Lo = getSDValue(Entry.first); 776 Hi = getSDValue(Entry.second); 777 } 778 779 void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo, 780 SDValue Hi) { 781 assert(Lo.getValueType() == 782 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 783 Hi.getValueType() == Lo.getValueType() && 784 "Invalid type for expanded integer"); 785 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 786 AnalyzeNewValue(Lo); 787 AnalyzeNewValue(Hi); 788 789 // Transfer debug values. Don't invalidate the source debug value until it's 790 // been transferred to the high and low bits. 791 if (DAG.getDataLayout().isBigEndian()) { 792 DAG.transferDbgValues(Op, Hi, 0, Hi.getValueSizeInBits(), false); 793 DAG.transferDbgValues(Op, Lo, Hi.getValueSizeInBits(), 794 Lo.getValueSizeInBits()); 795 } else { 796 DAG.transferDbgValues(Op, Lo, 0, Lo.getValueSizeInBits(), false); 797 DAG.transferDbgValues(Op, Hi, Lo.getValueSizeInBits(), 798 Hi.getValueSizeInBits()); 799 } 800 801 // Remember that this is the result of the node. 802 std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(Op)]; 803 assert((Entry.first == 0) && "Node already expanded"); 804 Entry.first = getTableId(Lo); 805 Entry.second = getTableId(Hi); 806 } 807 808 void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo, 809 SDValue &Hi) { 810 std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(Op)]; 811 assert((Entry.first != 0) && "Operand isn't expanded"); 812 Lo = getSDValue(Entry.first); 813 Hi = getSDValue(Entry.second); 814 } 815 816 void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo, 817 SDValue Hi) { 818 assert(Lo.getValueType() == 819 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 820 Hi.getValueType() == Lo.getValueType() && 821 "Invalid type for expanded float"); 822 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 823 AnalyzeNewValue(Lo); 824 AnalyzeNewValue(Hi); 825 826 std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(Op)]; 827 assert((Entry.first == 0) && "Node already expanded"); 828 Entry.first = getTableId(Lo); 829 Entry.second = getTableId(Hi); 830 } 831 832 void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo, 833 SDValue &Hi) { 834 std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)]; 835 Lo = getSDValue(Entry.first); 836 Hi = getSDValue(Entry.second); 837 assert(Lo.getNode() && "Operand isn't split"); 838 ; 839 } 840 841 void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo, 842 SDValue Hi) { 843 assert(Lo.getValueType().getVectorElementType() == 844 Op.getValueType().getVectorElementType() && 845 Lo.getValueType().getVectorElementCount() * 2 == 846 Op.getValueType().getVectorElementCount() && 847 Hi.getValueType() == Lo.getValueType() && 848 "Invalid type for split vector"); 849 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 850 AnalyzeNewValue(Lo); 851 AnalyzeNewValue(Hi); 852 853 // Remember that this is the result of the node. 854 std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)]; 855 assert((Entry.first == 0) && "Node already split"); 856 Entry.first = getTableId(Lo); 857 Entry.second = getTableId(Hi); 858 } 859 860 void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) { 861 assert(Result.getValueType() == 862 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 863 "Invalid type for widened vector"); 864 AnalyzeNewValue(Result); 865 866 auto &OpIdEntry = WidenedVectors[getTableId(Op)]; 867 assert((OpIdEntry == 0) && "Node already widened!"); 868 OpIdEntry = getTableId(Result); 869 } 870 871 872 //===----------------------------------------------------------------------===// 873 // Utilities. 874 //===----------------------------------------------------------------------===// 875 876 /// Convert to an integer of the same size. 877 SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) { 878 unsigned BitWidth = Op.getValueSizeInBits(); 879 return DAG.getNode(ISD::BITCAST, SDLoc(Op), 880 EVT::getIntegerVT(*DAG.getContext(), BitWidth), Op); 881 } 882 883 /// Convert to a vector of integers of the same size. 884 SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) { 885 assert(Op.getValueType().isVector() && "Only applies to vectors!"); 886 unsigned EltWidth = Op.getScalarValueSizeInBits(); 887 EVT EltNVT = EVT::getIntegerVT(*DAG.getContext(), EltWidth); 888 auto EltCnt = Op.getValueType().getVectorElementCount(); 889 return DAG.getNode(ISD::BITCAST, SDLoc(Op), 890 EVT::getVectorVT(*DAG.getContext(), EltNVT, EltCnt), Op); 891 } 892 893 SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op, 894 EVT DestVT) { 895 SDLoc dl(Op); 896 // Create the stack frame object. Make sure it is aligned for both 897 // the source and destination types. 898 899 // In cases where the vector is illegal it will be broken down into parts 900 // and stored in parts - we should use the alignment for the smallest part. 901 Align DestAlign = DAG.getReducedAlign(DestVT, /*UseABI=*/false); 902 Align OpAlign = DAG.getReducedAlign(Op.getValueType(), /*UseABI=*/false); 903 Align Align = std::max(DestAlign, OpAlign); 904 SDValue StackPtr = 905 DAG.CreateStackTemporary(Op.getValueType().getStoreSize(), Align); 906 // Emit a store to the stack slot. 907 SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Op, StackPtr, 908 MachinePointerInfo(), Align); 909 // Result is a load from the stack slot. 910 return DAG.getLoad(DestVT, dl, Store, StackPtr, MachinePointerInfo(), Align); 911 } 912 913 /// Replace the node's results with custom code provided by the target and 914 /// return "true", or do nothing and return "false". 915 /// The last parameter is FALSE if we are dealing with a node with legal 916 /// result types and illegal operand. The second parameter denotes the type of 917 /// illegal OperandNo in that case. 918 /// The last parameter being TRUE means we are dealing with a 919 /// node with illegal result types. The second parameter denotes the type of 920 /// illegal ResNo in that case. 921 bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) { 922 // See if the target wants to custom lower this node. 923 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom) 924 return false; 925 926 SmallVector<SDValue, 8> Results; 927 if (LegalizeResult) 928 TLI.ReplaceNodeResults(N, Results, DAG); 929 else 930 TLI.LowerOperationWrapper(N, Results, DAG); 931 932 if (Results.empty()) 933 // The target didn't want to custom lower it after all. 934 return false; 935 936 // Make everything that once used N's values now use those in Results instead. 937 assert(Results.size() == N->getNumValues() && 938 "Custom lowering returned the wrong number of results!"); 939 for (unsigned i = 0, e = Results.size(); i != e; ++i) { 940 ReplaceValueWith(SDValue(N, i), Results[i]); 941 } 942 return true; 943 } 944 945 946 /// Widen the node's results with custom code provided by the target and return 947 /// "true", or do nothing and return "false". 948 bool DAGTypeLegalizer::CustomWidenLowerNode(SDNode *N, EVT VT) { 949 // See if the target wants to custom lower this node. 950 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom) 951 return false; 952 953 SmallVector<SDValue, 8> Results; 954 TLI.ReplaceNodeResults(N, Results, DAG); 955 956 if (Results.empty()) 957 // The target didn't want to custom widen lower its result after all. 958 return false; 959 960 // Update the widening map. 961 assert(Results.size() == N->getNumValues() && 962 "Custom lowering returned the wrong number of results!"); 963 for (unsigned i = 0, e = Results.size(); i != e; ++i) { 964 // If this is a chain output or already widened just replace it. 965 bool WasWidened = SDValue(N, i).getValueType() != Results[i].getValueType(); 966 if (WasWidened) 967 SetWidenedVector(SDValue(N, i), Results[i]); 968 else 969 ReplaceValueWith(SDValue(N, i), Results[i]); 970 } 971 return true; 972 } 973 974 SDValue DAGTypeLegalizer::DisintegrateMERGE_VALUES(SDNode *N, unsigned ResNo) { 975 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 976 if (i != ResNo) 977 ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i))); 978 return SDValue(N->getOperand(ResNo)); 979 } 980 981 /// Use ISD::EXTRACT_ELEMENT nodes to extract the low and high parts of the 982 /// given value. 983 void DAGTypeLegalizer::GetPairElements(SDValue Pair, 984 SDValue &Lo, SDValue &Hi) { 985 SDLoc dl(Pair); 986 EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), Pair.getValueType()); 987 std::tie(Lo, Hi) = DAG.SplitScalar(Pair, dl, NVT, NVT); 988 } 989 990 /// Build an integer with low bits Lo and high bits Hi. 991 SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) { 992 // Arbitrarily use dlHi for result SDLoc 993 SDLoc dlHi(Hi); 994 SDLoc dlLo(Lo); 995 EVT LVT = Lo.getValueType(); 996 EVT HVT = Hi.getValueType(); 997 EVT NVT = EVT::getIntegerVT(*DAG.getContext(), 998 LVT.getSizeInBits() + HVT.getSizeInBits()); 999 1000 EVT ShiftAmtVT = TLI.getShiftAmountTy(NVT, DAG.getDataLayout()); 1001 Lo = DAG.getNode(ISD::ZERO_EXTEND, dlLo, NVT, Lo); 1002 Hi = DAG.getNode(ISD::ANY_EXTEND, dlHi, NVT, Hi); 1003 Hi = DAG.getNode(ISD::SHL, dlHi, NVT, Hi, 1004 DAG.getConstant(LVT.getSizeInBits(), dlHi, ShiftAmtVT)); 1005 return DAG.getNode(ISD::OR, dlHi, NVT, Lo, Hi); 1006 } 1007 1008 /// Promote the given target boolean to a target boolean of the given type. 1009 /// A target boolean is an integer value, not necessarily of type i1, the bits 1010 /// of which conform to getBooleanContents. 1011 /// 1012 /// ValVT is the type of values that produced the boolean. 1013 SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT ValVT) { 1014 return TLI.promoteTargetBoolean(DAG, Bool, ValVT); 1015 } 1016 1017 /// Return the lower LoVT bits of Op in Lo and the upper HiVT bits in 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. 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. 1055 bool SelectionDAG::LegalizeTypes() { 1056 return DAGTypeLegalizer(*this).run(); 1057 } 1058