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