1 //===-- LegalizeTypes.cpp - Common code for DAG type legalizer ------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements the SelectionDAG::LegalizeTypes method. It transforms 10 // an arbitrary well-formed SelectionDAG to only consist of legal types. This 11 // is common code shared among the LegalizeTypes*.cpp files. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "LegalizeTypes.h" 16 #include "SDNodeDbgValue.h" 17 #include "llvm/ADT/SetVector.h" 18 #include "llvm/CodeGen/MachineFunction.h" 19 #include "llvm/IR/CallingConv.h" 20 #include "llvm/IR/DataLayout.h" 21 #include "llvm/Support/CommandLine.h" 22 #include "llvm/Support/ErrorHandling.h" 23 #include "llvm/Support/raw_ostream.h" 24 using namespace llvm; 25 26 #define DEBUG_TYPE "legalize-types" 27 28 static cl::opt<bool> 29 EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden); 30 31 /// Do extensive, expensive, sanity checking. 32 void DAGTypeLegalizer::PerformExpensiveChecks() { 33 // If a node is not processed, then none of its values should be mapped by any 34 // of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues. 35 36 // If a node is processed, then each value with an illegal type must be mapped 37 // by exactly one of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues. 38 // Values with a legal type may be mapped by ReplacedValues, but not by any of 39 // the other maps. 40 41 // Note that these invariants may not hold momentarily when processing a node: 42 // the node being processed may be put in a map before being marked Processed. 43 44 // Note that it is possible to have nodes marked NewNode in the DAG. This can 45 // occur in two ways. Firstly, a node may be created during legalization but 46 // never passed to the legalization core. This is usually due to the implicit 47 // folding that occurs when using the DAG.getNode operators. Secondly, a new 48 // node may be passed to the legalization core, but when analyzed may morph 49 // into a different node, leaving the original node as a NewNode in the DAG. 50 // A node may morph if one of its operands changes during analysis. Whether 51 // it actually morphs or not depends on whether, after updating its operands, 52 // it is equivalent to an existing node: if so, it morphs into that existing 53 // node (CSE). An operand can change during analysis if the operand is a new 54 // node that morphs, or it is a processed value that was mapped to some other 55 // value (as recorded in ReplacedValues) in which case the operand is turned 56 // into that other value. If a node morphs then the node it morphed into will 57 // be used instead of it for legalization, however the original node continues 58 // to live on in the DAG. 59 // The conclusion is that though there may be nodes marked NewNode in the DAG, 60 // all uses of such nodes are also marked NewNode: the result is a fungus of 61 // NewNodes growing on top of the useful nodes, and perhaps using them, but 62 // not used by them. 63 64 // If a value is mapped by ReplacedValues, then it must have no uses, except 65 // by nodes marked NewNode (see above). 66 67 // The final node obtained by mapping by ReplacedValues is not marked NewNode. 68 // Note that ReplacedValues should be applied iteratively. 69 70 // Note that the ReplacedValues map may also map deleted nodes (by iterating 71 // over the DAG we never dereference deleted nodes). This means that it may 72 // also map nodes marked NewNode if the deallocated memory was reallocated as 73 // another node, and that new node was not seen by the LegalizeTypes machinery 74 // (for example because it was created but not used). In general, we cannot 75 // distinguish between new nodes and deleted nodes. 76 SmallVector<SDNode*, 16> NewNodes; 77 for (SDNode &Node : DAG.allnodes()) { 78 // Remember nodes marked NewNode - they are subject to extra checking below. 79 if (Node.getNodeId() == NewNode) 80 NewNodes.push_back(&Node); 81 82 for (unsigned i = 0, e = Node.getNumValues(); i != e; ++i) { 83 SDValue Res(&Node, i); 84 bool Failed = false; 85 // Don't create a value in map. 86 auto ResId = (ValueToIdMap.count(Res)) ? ValueToIdMap[Res] : 0; 87 88 unsigned Mapped = 0; 89 if (ResId && (ReplacedValues.find(ResId) != ReplacedValues.end())) { 90 Mapped |= 1; 91 // Check that remapped values are only used by nodes marked NewNode. 92 for (SDNode::use_iterator UI = Node.use_begin(), UE = Node.use_end(); 93 UI != UE; ++UI) 94 if (UI.getUse().getResNo() == i) 95 assert(UI->getNodeId() == NewNode && 96 "Remapped value has non-trivial use!"); 97 98 // Check that the final result of applying ReplacedValues is not 99 // marked NewNode. 100 auto NewValId = ReplacedValues[ResId]; 101 auto I = ReplacedValues.find(NewValId); 102 while (I != ReplacedValues.end()) { 103 NewValId = I->second; 104 I = ReplacedValues.find(NewValId); 105 } 106 SDValue NewVal = getSDValue(NewValId); 107 (void)NewVal; 108 assert(NewVal.getNode()->getNodeId() != NewNode && 109 "ReplacedValues maps to a new node!"); 110 } 111 if (ResId && PromotedIntegers.find(ResId) != PromotedIntegers.end()) 112 Mapped |= 2; 113 if (ResId && SoftenedFloats.find(ResId) != SoftenedFloats.end()) 114 Mapped |= 4; 115 if (ResId && ScalarizedVectors.find(ResId) != ScalarizedVectors.end()) 116 Mapped |= 8; 117 if (ResId && ExpandedIntegers.find(ResId) != ExpandedIntegers.end()) 118 Mapped |= 16; 119 if (ResId && ExpandedFloats.find(ResId) != ExpandedFloats.end()) 120 Mapped |= 32; 121 if (ResId && SplitVectors.find(ResId) != SplitVectors.end()) 122 Mapped |= 64; 123 if (ResId && WidenedVectors.find(ResId) != WidenedVectors.end()) 124 Mapped |= 128; 125 if (ResId && PromotedFloats.find(ResId) != PromotedFloats.end()) 126 Mapped |= 256; 127 if (ResId && SoftPromotedHalfs.find(ResId) != SoftPromotedHalfs.end()) 128 Mapped |= 512; 129 130 if (Node.getNodeId() != Processed) { 131 // Since we allow ReplacedValues to map deleted nodes, it may map nodes 132 // marked NewNode too, since a deleted node may have been reallocated as 133 // another node that has not been seen by the LegalizeTypes machinery. 134 if ((Node.getNodeId() == NewNode && Mapped > 1) || 135 (Node.getNodeId() != NewNode && Mapped != 0)) { 136 dbgs() << "Unprocessed value in a map!"; 137 Failed = true; 138 } 139 } else if (isTypeLegal(Res.getValueType()) || IgnoreNodeResults(&Node)) { 140 if (Mapped > 1) { 141 dbgs() << "Value with legal type was transformed!"; 142 Failed = true; 143 } 144 } else { 145 if (Mapped == 0) { 146 dbgs() << "Processed value not in any map!"; 147 Failed = true; 148 } else if (Mapped & (Mapped - 1)) { 149 dbgs() << "Value in multiple maps!"; 150 Failed = true; 151 } 152 } 153 154 if (Failed) { 155 if (Mapped & 1) 156 dbgs() << " ReplacedValues"; 157 if (Mapped & 2) 158 dbgs() << " PromotedIntegers"; 159 if (Mapped & 4) 160 dbgs() << " SoftenedFloats"; 161 if (Mapped & 8) 162 dbgs() << " ScalarizedVectors"; 163 if (Mapped & 16) 164 dbgs() << " ExpandedIntegers"; 165 if (Mapped & 32) 166 dbgs() << " ExpandedFloats"; 167 if (Mapped & 64) 168 dbgs() << " SplitVectors"; 169 if (Mapped & 128) 170 dbgs() << " WidenedVectors"; 171 if (Mapped & 256) 172 dbgs() << " PromotedFloats"; 173 if (Mapped & 512) 174 dbgs() << " SoftPromoteHalfs"; 175 dbgs() << "\n"; 176 llvm_unreachable(nullptr); 177 } 178 } 179 } 180 181 #ifndef NDEBUG 182 // Checked that NewNodes are only used by other NewNodes. 183 for (unsigned i = 0, e = NewNodes.size(); i != e; ++i) { 184 SDNode *N = NewNodes[i]; 185 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 186 UI != UE; ++UI) 187 assert(UI->getNodeId() == NewNode && "NewNode used by non-NewNode!"); 188 } 189 #endif 190 } 191 192 /// This is the main entry point for the type legalizer. This does a top-down 193 /// traversal of the dag, legalizing types as it goes. Returns "true" if it made 194 /// any changes. 195 bool DAGTypeLegalizer::run() { 196 bool Changed = false; 197 198 // Create a dummy node (which is not added to allnodes), that adds a reference 199 // to the root node, preventing it from being deleted, and tracking any 200 // changes of the root. 201 HandleSDNode Dummy(DAG.getRoot()); 202 Dummy.setNodeId(Unanalyzed); 203 204 // The root of the dag may dangle to deleted nodes until the type legalizer is 205 // done. Set it to null to avoid confusion. 206 DAG.setRoot(SDValue()); 207 208 // Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess' 209 // (and remembering them) if they are leaves and assigning 'Unanalyzed' if 210 // non-leaves. 211 for (SDNode &Node : DAG.allnodes()) { 212 if (Node.getNumOperands() == 0) { 213 Node.setNodeId(ReadyToProcess); 214 Worklist.push_back(&Node); 215 } else { 216 Node.setNodeId(Unanalyzed); 217 } 218 } 219 220 // Now that we have a set of nodes to process, handle them all. 221 while (!Worklist.empty()) { 222 #ifndef EXPENSIVE_CHECKS 223 if (EnableExpensiveChecks) 224 #endif 225 PerformExpensiveChecks(); 226 227 SDNode *N = Worklist.back(); 228 Worklist.pop_back(); 229 assert(N->getNodeId() == ReadyToProcess && 230 "Node should be ready if on worklist!"); 231 232 LLVM_DEBUG(dbgs() << "Legalizing node: "; N->dump(&DAG)); 233 if (IgnoreNodeResults(N)) { 234 LLVM_DEBUG(dbgs() << "Ignoring node results\n"); 235 goto ScanOperands; 236 } 237 238 // Scan the values produced by the node, checking to see if any result 239 // types are illegal. 240 for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) { 241 EVT ResultVT = N->getValueType(i); 242 LLVM_DEBUG(dbgs() << "Analyzing result type: " << ResultVT.getEVTString() 243 << "\n"); 244 switch (getTypeAction(ResultVT)) { 245 case TargetLowering::TypeLegal: 246 LLVM_DEBUG(dbgs() << "Legal result type\n"); 247 break; 248 case TargetLowering::TypeScalarizeScalableVector: 249 report_fatal_error( 250 "Scalarization of scalable vectors is not supported."); 251 // The following calls must take care of *all* of the node's results, 252 // not just the illegal result they were passed (this includes results 253 // with a legal type). Results can be remapped using ReplaceValueWith, 254 // or their promoted/expanded/etc values registered in PromotedIntegers, 255 // ExpandedIntegers etc. 256 case TargetLowering::TypePromoteInteger: 257 PromoteIntegerResult(N, i); 258 Changed = true; 259 goto NodeDone; 260 case TargetLowering::TypeExpandInteger: 261 ExpandIntegerResult(N, i); 262 Changed = true; 263 goto NodeDone; 264 case TargetLowering::TypeSoftenFloat: 265 SoftenFloatResult(N, i); 266 Changed = true; 267 goto NodeDone; 268 case TargetLowering::TypeExpandFloat: 269 ExpandFloatResult(N, i); 270 Changed = true; 271 goto NodeDone; 272 case TargetLowering::TypeScalarizeVector: 273 ScalarizeVectorResult(N, i); 274 Changed = true; 275 goto NodeDone; 276 case TargetLowering::TypeSplitVector: 277 SplitVectorResult(N, i); 278 Changed = true; 279 goto NodeDone; 280 case TargetLowering::TypeWidenVector: 281 WidenVectorResult(N, i); 282 Changed = true; 283 goto NodeDone; 284 case TargetLowering::TypePromoteFloat: 285 PromoteFloatResult(N, i); 286 Changed = true; 287 goto NodeDone; 288 case TargetLowering::TypeSoftPromoteHalf: 289 SoftPromoteHalfResult(N, i); 290 Changed = true; 291 goto NodeDone; 292 } 293 } 294 295 ScanOperands: 296 // Scan the operand list for the node, handling any nodes with operands that 297 // are illegal. 298 { 299 unsigned NumOperands = N->getNumOperands(); 300 bool NeedsReanalyzing = false; 301 unsigned i; 302 for (i = 0; i != NumOperands; ++i) { 303 if (IgnoreNodeResults(N->getOperand(i).getNode())) 304 continue; 305 306 const auto Op = N->getOperand(i); 307 LLVM_DEBUG(dbgs() << "Analyzing operand: "; Op.dump(&DAG)); 308 EVT OpVT = Op.getValueType(); 309 switch (getTypeAction(OpVT)) { 310 case TargetLowering::TypeLegal: 311 LLVM_DEBUG(dbgs() << "Legal operand\n"); 312 continue; 313 case TargetLowering::TypeScalarizeScalableVector: 314 report_fatal_error( 315 "Scalarization of scalable vectors is not supported."); 316 // The following calls must either replace all of the node's results 317 // using ReplaceValueWith, and return "false"; or update the node's 318 // operands in place, and return "true". 319 case TargetLowering::TypePromoteInteger: 320 NeedsReanalyzing = PromoteIntegerOperand(N, i); 321 Changed = true; 322 break; 323 case TargetLowering::TypeExpandInteger: 324 NeedsReanalyzing = ExpandIntegerOperand(N, i); 325 Changed = true; 326 break; 327 case TargetLowering::TypeSoftenFloat: 328 NeedsReanalyzing = SoftenFloatOperand(N, i); 329 Changed = true; 330 break; 331 case TargetLowering::TypeExpandFloat: 332 NeedsReanalyzing = ExpandFloatOperand(N, i); 333 Changed = true; 334 break; 335 case TargetLowering::TypeScalarizeVector: 336 NeedsReanalyzing = ScalarizeVectorOperand(N, i); 337 Changed = true; 338 break; 339 case TargetLowering::TypeSplitVector: 340 NeedsReanalyzing = SplitVectorOperand(N, i); 341 Changed = true; 342 break; 343 case TargetLowering::TypeWidenVector: 344 NeedsReanalyzing = WidenVectorOperand(N, i); 345 Changed = true; 346 break; 347 case TargetLowering::TypePromoteFloat: 348 NeedsReanalyzing = PromoteFloatOperand(N, i); 349 Changed = true; 350 break; 351 case TargetLowering::TypeSoftPromoteHalf: 352 NeedsReanalyzing = SoftPromoteHalfOperand(N, i); 353 Changed = true; 354 break; 355 } 356 break; 357 } 358 359 // The sub-method updated N in place. Check to see if any operands are new, 360 // and if so, mark them. If the node needs revisiting, don't add all users 361 // to the worklist etc. 362 if (NeedsReanalyzing) { 363 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 364 365 N->setNodeId(NewNode); 366 // Recompute the NodeId and correct processed operands, adding the node to 367 // the worklist if ready. 368 SDNode *M = AnalyzeNewNode(N); 369 if (M == N) 370 // The node didn't morph - nothing special to do, it will be revisited. 371 continue; 372 373 // The node morphed - this is equivalent to legalizing by replacing every 374 // value of N with the corresponding value of M. So do that now. 375 assert(N->getNumValues() == M->getNumValues() && 376 "Node morphing changed the number of results!"); 377 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 378 // Replacing the value takes care of remapping the new value. 379 ReplaceValueWith(SDValue(N, i), SDValue(M, i)); 380 assert(N->getNodeId() == NewNode && "Unexpected node state!"); 381 // The node continues to live on as part of the NewNode fungus that 382 // grows on top of the useful nodes. Nothing more needs to be done 383 // with it - move on to the next node. 384 continue; 385 } 386 387 if (i == NumOperands) { 388 LLVM_DEBUG(dbgs() << "Legally typed node: "; N->dump(&DAG); 389 dbgs() << "\n"); 390 } 391 } 392 NodeDone: 393 394 // If we reach here, the node was processed, potentially creating new nodes. 395 // Mark it as processed and add its users to the worklist as appropriate. 396 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 397 N->setNodeId(Processed); 398 399 for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end(); 400 UI != E; ++UI) { 401 SDNode *User = *UI; 402 int NodeId = User->getNodeId(); 403 404 // This node has two options: it can either be a new node or its Node ID 405 // may be a count of the number of operands it has that are not ready. 406 if (NodeId > 0) { 407 User->setNodeId(NodeId-1); 408 409 // If this was the last use it was waiting on, add it to the ready list. 410 if (NodeId-1 == ReadyToProcess) 411 Worklist.push_back(User); 412 continue; 413 } 414 415 // If this is an unreachable new node, then ignore it. If it ever becomes 416 // reachable by being used by a newly created node then it will be handled 417 // by AnalyzeNewNode. 418 if (NodeId == NewNode) 419 continue; 420 421 // Otherwise, this node is new: this is the first operand of it that 422 // became ready. Its new NodeId is the number of operands it has minus 1 423 // (as this node is now processed). 424 assert(NodeId == Unanalyzed && "Unknown node ID!"); 425 User->setNodeId(User->getNumOperands() - 1); 426 427 // If the node only has a single operand, it is now ready. 428 if (User->getNumOperands() == 1) 429 Worklist.push_back(User); 430 } 431 } 432 433 #ifndef EXPENSIVE_CHECKS 434 if (EnableExpensiveChecks) 435 #endif 436 PerformExpensiveChecks(); 437 438 // If the root changed (e.g. it was a dead load) update the root. 439 DAG.setRoot(Dummy.getValue()); 440 441 // Remove dead nodes. This is important to do for cleanliness but also before 442 // the checking loop below. Implicit folding by the DAG.getNode operators and 443 // node morphing can cause unreachable nodes to be around with their flags set 444 // to new. 445 DAG.RemoveDeadNodes(); 446 447 // In a debug build, scan all the nodes to make sure we found them all. This 448 // ensures that there are no cycles and that everything got processed. 449 #ifndef NDEBUG 450 for (SDNode &Node : DAG.allnodes()) { 451 bool Failed = false; 452 453 // Check that all result types are legal. 454 if (!IgnoreNodeResults(&Node)) 455 for (unsigned i = 0, NumVals = Node.getNumValues(); i < NumVals; ++i) 456 if (!isTypeLegal(Node.getValueType(i))) { 457 dbgs() << "Result type " << i << " illegal: "; 458 Node.dump(&DAG); 459 Failed = true; 460 } 461 462 // Check that all operand types are legal. 463 for (unsigned i = 0, NumOps = Node.getNumOperands(); i < NumOps; ++i) 464 if (!IgnoreNodeResults(Node.getOperand(i).getNode()) && 465 !isTypeLegal(Node.getOperand(i).getValueType())) { 466 dbgs() << "Operand type " << i << " illegal: "; 467 Node.getOperand(i).dump(&DAG); 468 Failed = true; 469 } 470 471 if (Node.getNodeId() != Processed) { 472 if (Node.getNodeId() == NewNode) 473 dbgs() << "New node not analyzed?\n"; 474 else if (Node.getNodeId() == Unanalyzed) 475 dbgs() << "Unanalyzed node not noticed?\n"; 476 else if (Node.getNodeId() > 0) 477 dbgs() << "Operand not processed?\n"; 478 else if (Node.getNodeId() == ReadyToProcess) 479 dbgs() << "Not added to worklist?\n"; 480 Failed = true; 481 } 482 483 if (Failed) { 484 Node.dump(&DAG); dbgs() << "\n"; 485 llvm_unreachable(nullptr); 486 } 487 } 488 #endif 489 490 return Changed; 491 } 492 493 /// The specified node is the root of a subtree of potentially new nodes. 494 /// Correct any processed operands (this may change the node) and calculate the 495 /// NodeId. If the node itself changes to a processed node, it is not remapped - 496 /// the caller needs to take care of this. Returns the potentially changed node. 497 SDNode *DAGTypeLegalizer::AnalyzeNewNode(SDNode *N) { 498 // If this was an existing node that is already done, we're done. 499 if (N->getNodeId() != NewNode && N->getNodeId() != Unanalyzed) 500 return N; 501 502 // Okay, we know that this node is new. Recursively walk all of its operands 503 // to see if they are new also. The depth of this walk is bounded by the size 504 // of the new tree that was constructed (usually 2-3 nodes), so we don't worry 505 // about revisiting of nodes. 506 // 507 // As we walk the operands, keep track of the number of nodes that are 508 // processed. If non-zero, this will become the new nodeid of this node. 509 // Operands may morph when they are analyzed. If so, the node will be 510 // updated after all operands have been analyzed. Since this is rare, 511 // the code tries to minimize overhead in the non-morphing case. 512 513 std::vector<SDValue> NewOps; 514 unsigned NumProcessed = 0; 515 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) { 516 SDValue OrigOp = N->getOperand(i); 517 SDValue Op = OrigOp; 518 519 AnalyzeNewValue(Op); // Op may morph. 520 521 if (Op.getNode()->getNodeId() == Processed) 522 ++NumProcessed; 523 524 if (!NewOps.empty()) { 525 // Some previous operand changed. Add this one to the list. 526 NewOps.push_back(Op); 527 } else if (Op != OrigOp) { 528 // This is the first operand to change - add all operands so far. 529 NewOps.insert(NewOps.end(), N->op_begin(), N->op_begin() + i); 530 NewOps.push_back(Op); 531 } 532 } 533 534 // Some operands changed - update the node. 535 if (!NewOps.empty()) { 536 SDNode *M = DAG.UpdateNodeOperands(N, NewOps); 537 if (M != N) { 538 // The node morphed into a different node. Normally for this to happen 539 // the original node would have to be marked NewNode. However this can 540 // in theory momentarily not be the case while ReplaceValueWith is doing 541 // its stuff. Mark the original node NewNode to help sanity checking. 542 N->setNodeId(NewNode); 543 if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed) 544 // It morphed into a previously analyzed node - nothing more to do. 545 return M; 546 547 // It morphed into a different new node. Do the equivalent of passing 548 // it to AnalyzeNewNode: expunge it and calculate the NodeId. No need 549 // to remap the operands, since they are the same as the operands we 550 // remapped above. 551 N = M; 552 } 553 } 554 555 // Calculate the NodeId. 556 N->setNodeId(N->getNumOperands() - NumProcessed); 557 if (N->getNodeId() == ReadyToProcess) 558 Worklist.push_back(N); 559 560 return N; 561 } 562 563 /// Call AnalyzeNewNode, updating the node in Val if needed. 564 /// If the node changes to a processed node, then remap it. 565 void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) { 566 Val.setNode(AnalyzeNewNode(Val.getNode())); 567 if (Val.getNode()->getNodeId() == Processed) 568 // We were passed a processed node, or it morphed into one - remap it. 569 RemapValue(Val); 570 } 571 572 /// If the specified value was already legalized to another value, 573 /// replace it by that value. 574 void DAGTypeLegalizer::RemapValue(SDValue &V) { 575 auto Id = getTableId(V); 576 V = getSDValue(Id); 577 } 578 579 void DAGTypeLegalizer::RemapId(TableId &Id) { 580 auto I = ReplacedValues.find(Id); 581 if (I != ReplacedValues.end()) { 582 assert(Id != I->second && "Id is mapped to itself."); 583 // Use path compression to speed up future lookups if values get multiply 584 // replaced with other values. 585 RemapId(I->second); 586 Id = I->second; 587 588 // Note that N = IdToValueMap[Id] it is possible to have 589 // N.getNode()->getNodeId() == NewNode at this point because it is possible 590 // for a node to be put in the map before being processed. 591 } 592 } 593 594 namespace { 595 /// This class is a DAGUpdateListener that listens for updates to nodes and 596 /// recomputes their ready state. 597 class NodeUpdateListener : public SelectionDAG::DAGUpdateListener { 598 DAGTypeLegalizer &DTL; 599 SmallSetVector<SDNode*, 16> &NodesToAnalyze; 600 public: 601 explicit NodeUpdateListener(DAGTypeLegalizer &dtl, 602 SmallSetVector<SDNode*, 16> &nta) 603 : SelectionDAG::DAGUpdateListener(dtl.getDAG()), 604 DTL(dtl), NodesToAnalyze(nta) {} 605 606 void NodeDeleted(SDNode *N, SDNode *E) override { 607 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 608 N->getNodeId() != DAGTypeLegalizer::Processed && 609 "Invalid node ID for RAUW deletion!"); 610 // It is possible, though rare, for the deleted node N to occur as a 611 // target in a map, so note the replacement N -> E in ReplacedValues. 612 assert(E && "Node not replaced?"); 613 DTL.NoteDeletion(N, E); 614 615 // In theory the deleted node could also have been scheduled for analysis. 616 // So remove it from the set of nodes which will be analyzed. 617 NodesToAnalyze.remove(N); 618 619 // In general nothing needs to be done for E, since it didn't change but 620 // only gained new uses. However N -> E was just added to ReplacedValues, 621 // and the result of a ReplacedValues mapping is not allowed to be marked 622 // NewNode. So if E is marked NewNode, then it needs to be analyzed. 623 if (E->getNodeId() == DAGTypeLegalizer::NewNode) 624 NodesToAnalyze.insert(E); 625 } 626 627 void NodeUpdated(SDNode *N) override { 628 // Node updates can mean pretty much anything. It is possible that an 629 // operand was set to something already processed (f.e.) in which case 630 // this node could become ready. Recompute its flags. 631 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 632 N->getNodeId() != DAGTypeLegalizer::Processed && 633 "Invalid node ID for RAUW deletion!"); 634 N->setNodeId(DAGTypeLegalizer::NewNode); 635 NodesToAnalyze.insert(N); 636 } 637 }; 638 } 639 640 641 /// The specified value was legalized to the specified other value. 642 /// Update the DAG and NodeIds replacing any uses of From to use To instead. 643 void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) { 644 assert(From.getNode() != To.getNode() && "Potential legalization loop!"); 645 646 // If expansion produced new nodes, make sure they are properly marked. 647 AnalyzeNewValue(To); 648 649 // Anything that used the old node should now use the new one. Note that this 650 // can potentially cause recursive merging. 651 SmallSetVector<SDNode*, 16> NodesToAnalyze; 652 NodeUpdateListener NUL(*this, NodesToAnalyze); 653 do { 654 655 // The old node may be present in a map like ExpandedIntegers or 656 // PromotedIntegers. Inform maps about the replacement. 657 auto FromId = getTableId(From); 658 auto ToId = getTableId(To); 659 660 if (FromId != ToId) 661 ReplacedValues[FromId] = ToId; 662 DAG.ReplaceAllUsesOfValueWith(From, To); 663 664 // Process the list of nodes that need to be reanalyzed. 665 while (!NodesToAnalyze.empty()) { 666 SDNode *N = NodesToAnalyze.pop_back_val(); 667 if (N->getNodeId() != DAGTypeLegalizer::NewNode) 668 // The node was analyzed while reanalyzing an earlier node - it is safe 669 // to skip. Note that this is not a morphing node - otherwise it would 670 // still be marked NewNode. 671 continue; 672 673 // Analyze the node's operands and recalculate the node ID. 674 SDNode *M = AnalyzeNewNode(N); 675 if (M != N) { 676 // The node morphed into a different node. Make everyone use the new 677 // node instead. 678 assert(M->getNodeId() != NewNode && "Analysis resulted in NewNode!"); 679 assert(N->getNumValues() == M->getNumValues() && 680 "Node morphing changed the number of results!"); 681 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) { 682 SDValue OldVal(N, i); 683 SDValue NewVal(M, i); 684 if (M->getNodeId() == Processed) 685 RemapValue(NewVal); 686 // OldVal may be a target of the ReplacedValues map which was marked 687 // NewNode to force reanalysis because it was updated. Ensure that 688 // anything that ReplacedValues mapped to OldVal will now be mapped 689 // all the way to NewVal. 690 auto OldValId = getTableId(OldVal); 691 auto NewValId = getTableId(NewVal); 692 DAG.ReplaceAllUsesOfValueWith(OldVal, NewVal); 693 if (OldValId != NewValId) 694 ReplacedValues[OldValId] = NewValId; 695 } 696 // The original node continues to exist in the DAG, marked NewNode. 697 } 698 } 699 // When recursively update nodes with new nodes, it is possible to have 700 // new uses of From due to CSE. If this happens, replace the new uses of 701 // From with To. 702 } while (!From.use_empty()); 703 } 704 705 void DAGTypeLegalizer::SetPromotedInteger(SDValue Op, SDValue Result) { 706 assert(Result.getValueType() == 707 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 708 "Invalid type for promoted integer"); 709 AnalyzeNewValue(Result); 710 711 auto &OpIdEntry = PromotedIntegers[getTableId(Op)]; 712 assert((OpIdEntry == 0) && "Node is already promoted!"); 713 OpIdEntry = getTableId(Result); 714 Result->setFlags(Op->getFlags()); 715 716 DAG.transferDbgValues(Op, Result); 717 } 718 719 void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) { 720 assert(Result.getValueType() == 721 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 722 "Invalid type for softened float"); 723 AnalyzeNewValue(Result); 724 725 auto &OpIdEntry = SoftenedFloats[getTableId(Op)]; 726 assert((OpIdEntry == 0) && "Node is already converted to integer!"); 727 OpIdEntry = getTableId(Result); 728 } 729 730 void DAGTypeLegalizer::SetPromotedFloat(SDValue Op, SDValue Result) { 731 assert(Result.getValueType() == 732 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 733 "Invalid type for promoted float"); 734 AnalyzeNewValue(Result); 735 736 auto &OpIdEntry = PromotedFloats[getTableId(Op)]; 737 assert((OpIdEntry == 0) && "Node is already promoted!"); 738 OpIdEntry = getTableId(Result); 739 } 740 741 void DAGTypeLegalizer::SetSoftPromotedHalf(SDValue Op, SDValue Result) { 742 assert(Result.getValueType() == MVT::i16 && 743 "Invalid type for soft-promoted half"); 744 AnalyzeNewValue(Result); 745 746 auto &OpIdEntry = SoftPromotedHalfs[getTableId(Op)]; 747 assert((OpIdEntry == 0) && "Node is already promoted!"); 748 OpIdEntry = getTableId(Result); 749 } 750 751 void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) { 752 // Note that in some cases vector operation operands may be greater than 753 // the vector element type. For example BUILD_VECTOR of type <1 x i1> with 754 // a constant i8 operand. 755 756 // We don't currently support the scalarization of scalable vector types. 757 assert(Result.getValueSizeInBits().getFixedSize() >= 758 Op.getScalarValueSizeInBits() && 759 "Invalid type for scalarized vector"); 760 AnalyzeNewValue(Result); 761 762 auto &OpIdEntry = ScalarizedVectors[getTableId(Op)]; 763 assert((OpIdEntry == 0) && "Node is already scalarized!"); 764 OpIdEntry = getTableId(Result); 765 } 766 767 void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo, 768 SDValue &Hi) { 769 std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(Op)]; 770 assert((Entry.first != 0) && "Operand isn't expanded"); 771 Lo = getSDValue(Entry.first); 772 Hi = getSDValue(Entry.second); 773 } 774 775 void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo, 776 SDValue Hi) { 777 assert(Lo.getValueType() == 778 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 779 Hi.getValueType() == Lo.getValueType() && 780 "Invalid type for expanded integer"); 781 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 782 AnalyzeNewValue(Lo); 783 AnalyzeNewValue(Hi); 784 785 // Transfer debug values. Don't invalidate the source debug value until it's 786 // been transferred to the high and low bits. 787 if (DAG.getDataLayout().isBigEndian()) { 788 DAG.transferDbgValues(Op, Hi, 0, Hi.getValueSizeInBits(), false); 789 DAG.transferDbgValues(Op, Lo, Hi.getValueSizeInBits(), 790 Lo.getValueSizeInBits()); 791 } else { 792 DAG.transferDbgValues(Op, Lo, 0, Lo.getValueSizeInBits(), false); 793 DAG.transferDbgValues(Op, Hi, Lo.getValueSizeInBits(), 794 Hi.getValueSizeInBits()); 795 } 796 797 // Remember that this is the result of the node. 798 std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(Op)]; 799 assert((Entry.first == 0) && "Node already expanded"); 800 Entry.first = getTableId(Lo); 801 Entry.second = getTableId(Hi); 802 } 803 804 void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo, 805 SDValue &Hi) { 806 std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(Op)]; 807 assert((Entry.first != 0) && "Operand isn't expanded"); 808 Lo = getSDValue(Entry.first); 809 Hi = getSDValue(Entry.second); 810 } 811 812 void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo, 813 SDValue Hi) { 814 assert(Lo.getValueType() == 815 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 816 Hi.getValueType() == Lo.getValueType() && 817 "Invalid type for expanded float"); 818 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 819 AnalyzeNewValue(Lo); 820 AnalyzeNewValue(Hi); 821 822 std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(Op)]; 823 assert((Entry.first == 0) && "Node already expanded"); 824 Entry.first = getTableId(Lo); 825 Entry.second = getTableId(Hi); 826 } 827 828 void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo, 829 SDValue &Hi) { 830 std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)]; 831 Lo = getSDValue(Entry.first); 832 Hi = getSDValue(Entry.second); 833 assert(Lo.getNode() && "Operand isn't split"); 834 ; 835 } 836 837 void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo, 838 SDValue Hi) { 839 assert(Lo.getValueType().getVectorElementType() == 840 Op.getValueType().getVectorElementType() && 841 Lo.getValueType().getVectorElementCount() * 2 == 842 Op.getValueType().getVectorElementCount() && 843 Hi.getValueType() == Lo.getValueType() && 844 "Invalid type for split vector"); 845 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 846 AnalyzeNewValue(Lo); 847 AnalyzeNewValue(Hi); 848 849 // Remember that this is the result of the node. 850 std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)]; 851 assert((Entry.first == 0) && "Node already split"); 852 Entry.first = getTableId(Lo); 853 Entry.second = getTableId(Hi); 854 } 855 856 void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) { 857 assert(Result.getValueType() == 858 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 859 "Invalid type for widened vector"); 860 AnalyzeNewValue(Result); 861 862 auto &OpIdEntry = WidenedVectors[getTableId(Op)]; 863 assert((OpIdEntry == 0) && "Node already widened!"); 864 OpIdEntry = getTableId(Result); 865 } 866 867 868 //===----------------------------------------------------------------------===// 869 // Utilities. 870 //===----------------------------------------------------------------------===// 871 872 /// Convert to an integer of the same size. 873 SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) { 874 unsigned BitWidth = Op.getValueSizeInBits(); 875 return DAG.getNode(ISD::BITCAST, SDLoc(Op), 876 EVT::getIntegerVT(*DAG.getContext(), BitWidth), Op); 877 } 878 879 /// Convert to a vector of integers of the same size. 880 SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) { 881 assert(Op.getValueType().isVector() && "Only applies to vectors!"); 882 unsigned EltWidth = Op.getScalarValueSizeInBits(); 883 EVT EltNVT = EVT::getIntegerVT(*DAG.getContext(), EltWidth); 884 auto EltCnt = Op.getValueType().getVectorElementCount(); 885 return DAG.getNode(ISD::BITCAST, SDLoc(Op), 886 EVT::getVectorVT(*DAG.getContext(), EltNVT, EltCnt), Op); 887 } 888 889 SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op, 890 EVT DestVT) { 891 SDLoc dl(Op); 892 // Create the stack frame object. Make sure it is aligned for both 893 // the source and destination types. 894 895 // In cases where the vector is illegal it will be broken down into parts 896 // and stored in parts - we should use the alignment for the smallest part. 897 Align DestAlign = DAG.getReducedAlign(DestVT, /*UseABI=*/false); 898 Align OpAlign = DAG.getReducedAlign(Op.getValueType(), /*UseABI=*/false); 899 Align Align = std::max(DestAlign, OpAlign); 900 SDValue StackPtr = 901 DAG.CreateStackTemporary(Op.getValueType().getStoreSize(), Align); 902 // Emit a store to the stack slot. 903 SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Op, StackPtr, 904 MachinePointerInfo(), Align); 905 // Result is a load from the stack slot. 906 return DAG.getLoad(DestVT, dl, Store, StackPtr, MachinePointerInfo(), Align); 907 } 908 909 /// Replace the node's results with custom code provided by the target and 910 /// return "true", or do nothing and return "false". 911 /// The last parameter is FALSE if we are dealing with a node with legal 912 /// result types and illegal operand. The second parameter denotes the type of 913 /// illegal OperandNo in that case. 914 /// The last parameter being TRUE means we are dealing with a 915 /// node with illegal result types. The second parameter denotes the type of 916 /// illegal ResNo in that case. 917 bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) { 918 // See if the target wants to custom lower this node. 919 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom) 920 return false; 921 922 SmallVector<SDValue, 8> Results; 923 if (LegalizeResult) 924 TLI.ReplaceNodeResults(N, Results, DAG); 925 else 926 TLI.LowerOperationWrapper(N, Results, DAG); 927 928 if (Results.empty()) 929 // The target didn't want to custom lower it after all. 930 return false; 931 932 // Make everything that once used N's values now use those in Results instead. 933 assert(Results.size() == N->getNumValues() && 934 "Custom lowering returned the wrong number of results!"); 935 for (unsigned i = 0, e = Results.size(); i != e; ++i) { 936 ReplaceValueWith(SDValue(N, i), Results[i]); 937 } 938 return true; 939 } 940 941 942 /// Widen the node's results with custom code provided by the target and return 943 /// "true", or do nothing and return "false". 944 bool DAGTypeLegalizer::CustomWidenLowerNode(SDNode *N, EVT VT) { 945 // See if the target wants to custom lower this node. 946 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom) 947 return false; 948 949 SmallVector<SDValue, 8> Results; 950 TLI.ReplaceNodeResults(N, Results, DAG); 951 952 if (Results.empty()) 953 // The target didn't want to custom widen lower its result after all. 954 return false; 955 956 // Update the widening map. 957 assert(Results.size() == N->getNumValues() && 958 "Custom lowering returned the wrong number of results!"); 959 for (unsigned i = 0, e = Results.size(); i != e; ++i) { 960 // If this is a chain output or already widened just replace it. 961 bool WasWidened = SDValue(N, i).getValueType() != Results[i].getValueType(); 962 if (WasWidened) 963 SetWidenedVector(SDValue(N, i), Results[i]); 964 else 965 ReplaceValueWith(SDValue(N, i), Results[i]); 966 } 967 return true; 968 } 969 970 SDValue DAGTypeLegalizer::DisintegrateMERGE_VALUES(SDNode *N, unsigned ResNo) { 971 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 972 if (i != ResNo) 973 ReplaceValueWith(SDValue(N, i), SDValue(N->getOperand(i))); 974 return SDValue(N->getOperand(ResNo)); 975 } 976 977 /// Use ISD::EXTRACT_ELEMENT nodes to extract the low and high parts of the 978 /// given value. 979 void DAGTypeLegalizer::GetPairElements(SDValue Pair, 980 SDValue &Lo, SDValue &Hi) { 981 SDLoc dl(Pair); 982 EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), Pair.getValueType()); 983 Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair, 984 DAG.getIntPtrConstant(0, dl)); 985 Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair, 986 DAG.getIntPtrConstant(1, dl)); 987 } 988 989 /// Build an integer with low bits Lo and high bits Hi. 990 SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) { 991 // Arbitrarily use dlHi for result SDLoc 992 SDLoc dlHi(Hi); 993 SDLoc dlLo(Lo); 994 EVT LVT = Lo.getValueType(); 995 EVT HVT = Hi.getValueType(); 996 EVT NVT = EVT::getIntegerVT(*DAG.getContext(), 997 LVT.getSizeInBits() + HVT.getSizeInBits()); 998 999 EVT ShiftAmtVT = TLI.getShiftAmountTy(NVT, DAG.getDataLayout(), false); 1000 Lo = DAG.getNode(ISD::ZERO_EXTEND, dlLo, NVT, Lo); 1001 Hi = DAG.getNode(ISD::ANY_EXTEND, dlHi, NVT, Hi); 1002 Hi = DAG.getNode(ISD::SHL, dlHi, NVT, Hi, 1003 DAG.getConstant(LVT.getSizeInBits(), dlHi, ShiftAmtVT)); 1004 return DAG.getNode(ISD::OR, dlHi, NVT, Lo, Hi); 1005 } 1006 1007 /// Promote the given target boolean to a target boolean of the given type. 1008 /// A target boolean is an integer value, not necessarily of type i1, the bits 1009 /// of which conform to getBooleanContents. 1010 /// 1011 /// ValVT is the type of values that produced the boolean. 1012 SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT ValVT) { 1013 SDLoc dl(Bool); 1014 EVT BoolVT = getSetCCResultType(ValVT); 1015 ISD::NodeType ExtendCode = 1016 TargetLowering::getExtendForContent(TLI.getBooleanContents(ValVT)); 1017 return DAG.getNode(ExtendCode, dl, BoolVT, Bool); 1018 } 1019 1020 /// Return the lower LoVT bits of Op in Lo and the upper HiVT bits in Hi. 1021 void DAGTypeLegalizer::SplitInteger(SDValue Op, 1022 EVT LoVT, EVT HiVT, 1023 SDValue &Lo, SDValue &Hi) { 1024 SDLoc dl(Op); 1025 assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() == 1026 Op.getValueSizeInBits() && "Invalid integer splitting!"); 1027 Lo = DAG.getNode(ISD::TRUNCATE, dl, LoVT, Op); 1028 unsigned ReqShiftAmountInBits = 1029 Log2_32_Ceil(Op.getValueType().getSizeInBits()); 1030 MVT ShiftAmountTy = 1031 TLI.getScalarShiftAmountTy(DAG.getDataLayout(), Op.getValueType()); 1032 if (ReqShiftAmountInBits > ShiftAmountTy.getSizeInBits()) 1033 ShiftAmountTy = MVT::getIntegerVT(NextPowerOf2(ReqShiftAmountInBits)); 1034 Hi = DAG.getNode(ISD::SRL, dl, Op.getValueType(), Op, 1035 DAG.getConstant(LoVT.getSizeInBits(), dl, ShiftAmountTy)); 1036 Hi = DAG.getNode(ISD::TRUNCATE, dl, HiVT, Hi); 1037 } 1038 1039 /// Return the lower and upper halves of Op's bits in a value type half the 1040 /// size of Op's. 1041 void DAGTypeLegalizer::SplitInteger(SDValue Op, 1042 SDValue &Lo, SDValue &Hi) { 1043 EVT HalfVT = 1044 EVT::getIntegerVT(*DAG.getContext(), Op.getValueSizeInBits() / 2); 1045 SplitInteger(Op, HalfVT, HalfVT, Lo, Hi); 1046 } 1047 1048 1049 //===----------------------------------------------------------------------===// 1050 // Entry Point 1051 //===----------------------------------------------------------------------===// 1052 1053 /// This transforms the SelectionDAG into a SelectionDAG that only uses types 1054 /// natively supported by the target. Returns "true" if it made any changes. 1055 /// 1056 /// Note that this is an involved process that may invalidate pointers into 1057 /// the graph. 1058 bool SelectionDAG::LegalizeTypes() { 1059 return DAGTypeLegalizer(*this).run(); 1060 } 1061