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" 24using namespace llvm; 25 26#define DEBUG_TYPE "legalize-types" 27 28static cl::opt<bool> 29EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden); 30 31/// Do extensive, expensive, sanity checking. 32void 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. 195bool 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 295ScanOperands: 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 } 392NodeDone: 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. 497SDNode *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. 565void 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. 574void DAGTypeLegalizer::RemapValue(SDValue &V) { 575 auto Id = getTableId(V); 576 V = getSDValue(Id); 577} 578 579void 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 594namespace { 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. 643void 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.back(); 667 NodesToAnalyze.pop_back(); 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 706void 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 Result->setFlags(Op->getFlags()); 716 717 DAG.transferDbgValues(Op, Result); 718} 719 720void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) { 721 assert(Result.getValueType() == 722 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 723 "Invalid type for softened float"); 724 AnalyzeNewValue(Result); 725 726 auto &OpIdEntry = SoftenedFloats[getTableId(Op)]; 727 assert((OpIdEntry == 0) && "Node is already converted to integer!"); 728 OpIdEntry = getTableId(Result); 729} 730 731void DAGTypeLegalizer::SetPromotedFloat(SDValue Op, SDValue Result) { 732 assert(Result.getValueType() == 733 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 734 "Invalid type for promoted float"); 735 AnalyzeNewValue(Result); 736 737 auto &OpIdEntry = PromotedFloats[getTableId(Op)]; 738 assert((OpIdEntry == 0) && "Node is already promoted!"); 739 OpIdEntry = getTableId(Result); 740} 741 742void DAGTypeLegalizer::SetSoftPromotedHalf(SDValue Op, SDValue Result) { 743 assert(Result.getValueType() == MVT::i16 && 744 "Invalid type for soft-promoted half"); 745 AnalyzeNewValue(Result); 746 747 auto &OpIdEntry = SoftPromotedHalfs[getTableId(Op)]; 748 assert((OpIdEntry == 0) && "Node is already promoted!"); 749 OpIdEntry = getTableId(Result); 750} 751 752void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) { 753 // Note that in some cases vector operation operands may be greater than 754 // the vector element type. For example BUILD_VECTOR of type <1 x i1> with 755 // a constant i8 operand. 756 assert(Result.getValueSizeInBits() >= Op.getScalarValueSizeInBits() && 757 "Invalid type for scalarized vector"); 758 AnalyzeNewValue(Result); 759 760 auto &OpIdEntry = ScalarizedVectors[getTableId(Op)]; 761 assert((OpIdEntry == 0) && "Node is already scalarized!"); 762 OpIdEntry = getTableId(Result); 763} 764 765void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo, 766 SDValue &Hi) { 767 std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(Op)]; 768 assert((Entry.first != 0) && "Operand isn't expanded"); 769 Lo = getSDValue(Entry.first); 770 Hi = getSDValue(Entry.second); 771} 772 773void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo, 774 SDValue Hi) { 775 assert(Lo.getValueType() == 776 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 777 Hi.getValueType() == Lo.getValueType() && 778 "Invalid type for expanded integer"); 779 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 780 AnalyzeNewValue(Lo); 781 AnalyzeNewValue(Hi); 782 783 // Transfer debug values. Don't invalidate the source debug value until it's 784 // been transferred to the high and low bits. 785 if (DAG.getDataLayout().isBigEndian()) { 786 DAG.transferDbgValues(Op, Hi, 0, Hi.getValueSizeInBits(), false); 787 DAG.transferDbgValues(Op, Lo, Hi.getValueSizeInBits(), 788 Lo.getValueSizeInBits()); 789 } else { 790 DAG.transferDbgValues(Op, Lo, 0, Lo.getValueSizeInBits(), false); 791 DAG.transferDbgValues(Op, Hi, Lo.getValueSizeInBits(), 792 Hi.getValueSizeInBits()); 793 } 794 795 // Remember that this is the result of the node. 796 std::pair<TableId, TableId> &Entry = ExpandedIntegers[getTableId(Op)]; 797 assert((Entry.first == 0) && "Node already expanded"); 798 Entry.first = getTableId(Lo); 799 Entry.second = getTableId(Hi); 800} 801 802void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo, 803 SDValue &Hi) { 804 std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(Op)]; 805 assert((Entry.first != 0) && "Operand isn't expanded"); 806 Lo = getSDValue(Entry.first); 807 Hi = getSDValue(Entry.second); 808} 809 810void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo, 811 SDValue Hi) { 812 assert(Lo.getValueType() == 813 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 814 Hi.getValueType() == Lo.getValueType() && 815 "Invalid type for expanded float"); 816 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 817 AnalyzeNewValue(Lo); 818 AnalyzeNewValue(Hi); 819 820 std::pair<TableId, TableId> &Entry = ExpandedFloats[getTableId(Op)]; 821 assert((Entry.first == 0) && "Node already expanded"); 822 Entry.first = getTableId(Lo); 823 Entry.second = getTableId(Hi); 824} 825 826void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo, 827 SDValue &Hi) { 828 std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)]; 829 Lo = getSDValue(Entry.first); 830 Hi = getSDValue(Entry.second); 831 assert(Lo.getNode() && "Operand isn't split"); 832 ; 833} 834 835void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo, 836 SDValue Hi) { 837 assert(Lo.getValueType().getVectorElementType() == 838 Op.getValueType().getVectorElementType() && 839 Lo.getValueType().getVectorElementCount() * 2 == 840 Op.getValueType().getVectorElementCount() && 841 Hi.getValueType() == Lo.getValueType() && 842 "Invalid type for split vector"); 843 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 844 AnalyzeNewValue(Lo); 845 AnalyzeNewValue(Hi); 846 847 // Remember that this is the result of the node. 848 std::pair<TableId, TableId> &Entry = SplitVectors[getTableId(Op)]; 849 assert((Entry.first == 0) && "Node already split"); 850 Entry.first = getTableId(Lo); 851 Entry.second = getTableId(Hi); 852} 853 854void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) { 855 assert(Result.getValueType() == 856 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 857 "Invalid type for widened vector"); 858 AnalyzeNewValue(Result); 859 860 auto &OpIdEntry = WidenedVectors[getTableId(Op)]; 861 assert((OpIdEntry == 0) && "Node already widened!"); 862 OpIdEntry = getTableId(Result); 863} 864 865 866//===----------------------------------------------------------------------===// 867// Utilities. 868//===----------------------------------------------------------------------===// 869 870/// Convert to an integer of the same size. 871SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) { 872 unsigned BitWidth = Op.getValueSizeInBits(); 873 return DAG.getNode(ISD::BITCAST, SDLoc(Op), 874 EVT::getIntegerVT(*DAG.getContext(), BitWidth), Op); 875} 876 877/// Convert to a vector of integers of the same size. 878SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) { 879 assert(Op.getValueType().isVector() && "Only applies to vectors!"); 880 unsigned EltWidth = Op.getScalarValueSizeInBits(); 881 EVT EltNVT = EVT::getIntegerVT(*DAG.getContext(), EltWidth); 882 auto EltCnt = Op.getValueType().getVectorElementCount(); 883 return DAG.getNode(ISD::BITCAST, SDLoc(Op), 884 EVT::getVectorVT(*DAG.getContext(), EltNVT, EltCnt), Op); 885} 886 887SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op, 888 EVT DestVT) { 889 SDLoc dl(Op); 890 // Create the stack frame object. Make sure it is aligned for both 891 // the source and destination types. 892 893 // In cases where the vector is illegal it will be broken down into parts 894 // and stored in parts - we should use the alignment for the smallest part. 895 Align DestAlign = DAG.getReducedAlign(DestVT, /*UseABI=*/false); 896 Align OpAlign = DAG.getReducedAlign(Op.getValueType(), /*UseABI=*/false); 897 Align Align = std::max(DestAlign, OpAlign); 898 SDValue StackPtr = 899 DAG.CreateStackTemporary(Op.getValueType().getStoreSize(), Align); 900 // Emit a store to the stack slot. 901 SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Op, StackPtr, 902 MachinePointerInfo(), Align); 903 // Result is a load from the stack slot. 904 return DAG.getLoad(DestVT, dl, Store, StackPtr, MachinePointerInfo(), Align); 905} 906 907/// Replace the node's results with custom code provided by the target and 908/// return "true", or do nothing and return "false". 909/// The last parameter is FALSE if we are dealing with a node with legal 910/// result types and illegal operand. The second parameter denotes the type of 911/// illegal OperandNo in that case. 912/// The last parameter being TRUE means we are dealing with a 913/// node with illegal result types. The second parameter denotes the type of 914/// illegal ResNo in that case. 915bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) { 916 // See if the target wants to custom lower this node. 917 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom) 918 return false; 919 920 SmallVector<SDValue, 8> Results; 921 if (LegalizeResult) 922 TLI.ReplaceNodeResults(N, Results, DAG); 923 else 924 TLI.LowerOperationWrapper(N, Results, DAG); 925 926 if (Results.empty()) 927 // The target didn't want to custom lower it after all. 928 return false; 929 930 // Make everything that once used N's values now use those in Results instead. 931 assert(Results.size() == N->getNumValues() && 932 "Custom lowering returned the wrong number of results!"); 933 for (unsigned i = 0, e = Results.size(); i != e; ++i) { 934 ReplaceValueWith(SDValue(N, i), Results[i]); 935 } 936 return true; 937} 938 939 940/// Widen the node's results with custom code provided by the target and return 941/// "true", or do nothing and return "false". 942bool DAGTypeLegalizer::CustomWidenLowerNode(SDNode *N, EVT VT) { 943 // See if the target wants to custom lower this node. 944 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom) 945 return false; 946 947 SmallVector<SDValue, 8> Results; 948 TLI.ReplaceNodeResults(N, Results, DAG); 949 950 if (Results.empty()) 951 // The target didn't want to custom widen lower its result after all. 952 return false; 953 954 // Update the widening map. 955 assert(Results.size() == N->getNumValues() && 956 "Custom lowering returned the wrong number of results!"); 957 for (unsigned i = 0, e = Results.size(); i != e; ++i) { 958 // If this is a chain output just replace it. 959 if (Results[i].getValueType() == MVT::Other) 960 ReplaceValueWith(SDValue(N, i), Results[i]); 961 else 962 SetWidenedVector(SDValue(N, i), Results[i]); 963 } 964 return true; 965} 966 967SDValue 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. 976void 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. 987SDValue 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. 1009SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT ValVT) { 1010 SDLoc dl(Bool); 1011 EVT BoolVT = getSetCCResultType(ValVT); 1012 ISD::NodeType ExtendCode = 1013 TargetLowering::getExtendForContent(TLI.getBooleanContents(ValVT)); 1014 return DAG.getNode(ExtendCode, dl, BoolVT, Bool); 1015} 1016 1017/// Return the lower LoVT bits of Op in Lo and the upper HiVT bits in Hi. 1018void 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. 1038void 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. 1055bool SelectionDAG::LegalizeTypes() { 1056 return DAGTypeLegalizer(*this).run(); 1057} 1058