LegalizeTypes.cpp revision 4437ae213d5435390f0750213b53ec807c047f22
1//===-- LegalizeTypes.cpp - Common code for DAG type legalizer ------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file implements the SelectionDAG::LegalizeTypes method. It transforms 11// an arbitrary well-formed SelectionDAG to only consist of legal types. This 12// is common code shared among the LegalizeTypes*.cpp files. 13// 14//===----------------------------------------------------------------------===// 15 16#include "LegalizeTypes.h" 17#include "llvm/CallingConv.h" 18#include "llvm/Target/TargetData.h" 19#include "llvm/ADT/SetVector.h" 20#include "llvm/Support/CommandLine.h" 21#include "llvm/Support/ErrorHandling.h" 22#include "llvm/Support/raw_ostream.h" 23using namespace llvm; 24 25static cl::opt<bool> 26EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden); 27 28/// PerformExpensiveChecks - Do extensive, expensive, sanity checking. 29void DAGTypeLegalizer::PerformExpensiveChecks() { 30 // If a node is not processed, then none of its values should be mapped by any 31 // of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues. 32 33 // If a node is processed, then each value with an illegal type must be mapped 34 // by exactly one of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues. 35 // Values with a legal type may be mapped by ReplacedValues, but not by any of 36 // the other maps. 37 38 // Note that these invariants may not hold momentarily when processing a node: 39 // the node being processed may be put in a map before being marked Processed. 40 41 // Note that it is possible to have nodes marked NewNode in the DAG. This can 42 // occur in two ways. Firstly, a node may be created during legalization but 43 // never passed to the legalization core. This is usually due to the implicit 44 // folding that occurs when using the DAG.getNode operators. Secondly, a new 45 // node may be passed to the legalization core, but when analyzed may morph 46 // into a different node, leaving the original node as a NewNode in the DAG. 47 // A node may morph if one of its operands changes during analysis. Whether 48 // it actually morphs or not depends on whether, after updating its operands, 49 // it is equivalent to an existing node: if so, it morphs into that existing 50 // node (CSE). An operand can change during analysis if the operand is a new 51 // node that morphs, or it is a processed value that was mapped to some other 52 // value (as recorded in ReplacedValues) in which case the operand is turned 53 // into that other value. If a node morphs then the node it morphed into will 54 // be used instead of it for legalization, however the original node continues 55 // to live on in the DAG. 56 // The conclusion is that though there may be nodes marked NewNode in the DAG, 57 // all uses of such nodes are also marked NewNode: the result is a fungus of 58 // NewNodes growing on top of the useful nodes, and perhaps using them, but 59 // not used by them. 60 61 // If a value is mapped by ReplacedValues, then it must have no uses, except 62 // by nodes marked NewNode (see above). 63 64 // The final node obtained by mapping by ReplacedValues is not marked NewNode. 65 // Note that ReplacedValues should be applied iteratively. 66 67 // Note that the ReplacedValues map may also map deleted nodes. By iterating 68 // over the DAG we only consider non-deleted nodes. 69 SmallVector<SDNode*, 16> NewNodes; 70 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 71 E = DAG.allnodes_end(); I != E; ++I) { 72 // Remember nodes marked NewNode - they are subject to extra checking below. 73 if (I->getNodeId() == NewNode) 74 NewNodes.push_back(I); 75 76 for (unsigned i = 0, e = I->getNumValues(); i != e; ++i) { 77 SDValue Res(I, i); 78 bool Failed = false; 79 80 unsigned Mapped = 0; 81 if (ReplacedValues.find(Res) != ReplacedValues.end()) { 82 Mapped |= 1; 83 // Check that remapped values are only used by nodes marked NewNode. 84 for (SDNode::use_iterator UI = I->use_begin(), UE = I->use_end(); 85 UI != UE; ++UI) 86 if (UI.getUse().getResNo() == i) 87 assert(UI->getNodeId() == NewNode && 88 "Remapped value has non-trivial use!"); 89 90 // Check that the final result of applying ReplacedValues is not 91 // marked NewNode. 92 SDValue NewVal = ReplacedValues[Res]; 93 DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(NewVal); 94 while (I != ReplacedValues.end()) { 95 NewVal = I->second; 96 I = ReplacedValues.find(NewVal); 97 } 98 assert(NewVal.getNode()->getNodeId() != NewNode && 99 "ReplacedValues maps to a new node!"); 100 } 101 if (PromotedIntegers.find(Res) != PromotedIntegers.end()) 102 Mapped |= 2; 103 if (SoftenedFloats.find(Res) != SoftenedFloats.end()) 104 Mapped |= 4; 105 if (ScalarizedVectors.find(Res) != ScalarizedVectors.end()) 106 Mapped |= 8; 107 if (ExpandedIntegers.find(Res) != ExpandedIntegers.end()) 108 Mapped |= 16; 109 if (ExpandedFloats.find(Res) != ExpandedFloats.end()) 110 Mapped |= 32; 111 if (SplitVectors.find(Res) != SplitVectors.end()) 112 Mapped |= 64; 113 if (WidenedVectors.find(Res) != WidenedVectors.end()) 114 Mapped |= 128; 115 116 if (I->getNodeId() != Processed) { 117 if (Mapped != 0) { 118 errs() << "Unprocessed value in a map!"; 119 Failed = true; 120 } 121 } else if (isTypeLegal(Res.getValueType()) || IgnoreNodeResults(I)) { 122 if (Mapped > 1) { 123 errs() << "Value with legal type was transformed!"; 124 Failed = true; 125 } 126 } else { 127 if (Mapped == 0) { 128 errs() << "Processed value not in any map!"; 129 Failed = true; 130 } else if (Mapped & (Mapped - 1)) { 131 errs() << "Value in multiple maps!"; 132 Failed = true; 133 } 134 } 135 136 if (Failed) { 137 if (Mapped & 1) 138 errs() << " ReplacedValues"; 139 if (Mapped & 2) 140 errs() << " PromotedIntegers"; 141 if (Mapped & 4) 142 errs() << " SoftenedFloats"; 143 if (Mapped & 8) 144 errs() << " ScalarizedVectors"; 145 if (Mapped & 16) 146 errs() << " ExpandedIntegers"; 147 if (Mapped & 32) 148 errs() << " ExpandedFloats"; 149 if (Mapped & 64) 150 errs() << " SplitVectors"; 151 if (Mapped & 128) 152 errs() << " WidenedVectors"; 153 errs() << "\n"; 154 llvm_unreachable(0); 155 } 156 } 157 } 158 159 // Checked that NewNodes are only used by other NewNodes. 160 for (unsigned i = 0, e = NewNodes.size(); i != e; ++i) { 161 SDNode *N = NewNodes[i]; 162 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 163 UI != UE; ++UI) 164 assert(UI->getNodeId() == NewNode && "NewNode used by non-NewNode!"); 165 } 166} 167 168/// run - This is the main entry point for the type legalizer. This does a 169/// top-down traversal of the dag, legalizing types as it goes. Returns "true" 170/// if it made any changes. 171bool DAGTypeLegalizer::run() { 172 bool Changed = false; 173 174 // Create a dummy node (which is not added to allnodes), that adds a reference 175 // to the root node, preventing it from being deleted, and tracking any 176 // changes of the root. 177 HandleSDNode Dummy(DAG.getRoot()); 178 Dummy.setNodeId(Unanalyzed); 179 180 // The root of the dag may dangle to deleted nodes until the type legalizer is 181 // done. Set it to null to avoid confusion. 182 DAG.setRoot(SDValue()); 183 184 // Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess' 185 // (and remembering them) if they are leaves and assigning 'Unanalyzed' if 186 // non-leaves. 187 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 188 E = DAG.allnodes_end(); I != E; ++I) { 189 if (I->getNumOperands() == 0) { 190 I->setNodeId(ReadyToProcess); 191 Worklist.push_back(I); 192 } else { 193 I->setNodeId(Unanalyzed); 194 } 195 } 196 197 // Now that we have a set of nodes to process, handle them all. 198 while (!Worklist.empty()) { 199#ifndef XDEBUG 200 if (EnableExpensiveChecks) 201#endif 202 PerformExpensiveChecks(); 203 204 SDNode *N = Worklist.back(); 205 Worklist.pop_back(); 206 assert(N->getNodeId() == ReadyToProcess && 207 "Node should be ready if on worklist!"); 208 209 if (IgnoreNodeResults(N)) 210 goto ScanOperands; 211 212 // Scan the values produced by the node, checking to see if any result 213 // types are illegal. 214 for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) { 215 EVT ResultVT = N->getValueType(i); 216 switch (getTypeAction(ResultVT)) { 217 default: 218 assert(false && "Unknown action!"); 219 case Legal: 220 break; 221 // The following calls must take care of *all* of the node's results, 222 // not just the illegal result they were passed (this includes results 223 // with a legal type). Results can be remapped using ReplaceValueWith, 224 // or their promoted/expanded/etc values registered in PromotedIntegers, 225 // ExpandedIntegers etc. 226 case PromoteInteger: 227 PromoteIntegerResult(N, i); 228 Changed = true; 229 goto NodeDone; 230 case ExpandInteger: 231 ExpandIntegerResult(N, i); 232 Changed = true; 233 goto NodeDone; 234 case SoftenFloat: 235 SoftenFloatResult(N, i); 236 Changed = true; 237 goto NodeDone; 238 case ExpandFloat: 239 ExpandFloatResult(N, i); 240 Changed = true; 241 goto NodeDone; 242 case ScalarizeVector: 243 ScalarizeVectorResult(N, i); 244 Changed = true; 245 goto NodeDone; 246 case SplitVector: 247 SplitVectorResult(N, i); 248 Changed = true; 249 goto NodeDone; 250 case WidenVector: 251 WidenVectorResult(N, i); 252 Changed = true; 253 goto NodeDone; 254 } 255 } 256 257ScanOperands: 258 // Scan the operand list for the node, handling any nodes with operands that 259 // are illegal. 260 { 261 unsigned NumOperands = N->getNumOperands(); 262 bool NeedsReanalyzing = false; 263 unsigned i; 264 for (i = 0; i != NumOperands; ++i) { 265 if (IgnoreNodeResults(N->getOperand(i).getNode())) 266 continue; 267 268 EVT OpVT = N->getOperand(i).getValueType(); 269 switch (getTypeAction(OpVT)) { 270 default: 271 assert(false && "Unknown action!"); 272 case Legal: 273 continue; 274 // The following calls must either replace all of the node's results 275 // using ReplaceValueWith, and return "false"; or update the node's 276 // operands in place, and return "true". 277 case PromoteInteger: 278 NeedsReanalyzing = PromoteIntegerOperand(N, i); 279 Changed = true; 280 break; 281 case ExpandInteger: 282 NeedsReanalyzing = ExpandIntegerOperand(N, i); 283 Changed = true; 284 break; 285 case SoftenFloat: 286 NeedsReanalyzing = SoftenFloatOperand(N, i); 287 Changed = true; 288 break; 289 case ExpandFloat: 290 NeedsReanalyzing = ExpandFloatOperand(N, i); 291 Changed = true; 292 break; 293 case ScalarizeVector: 294 NeedsReanalyzing = ScalarizeVectorOperand(N, i); 295 Changed = true; 296 break; 297 case SplitVector: 298 NeedsReanalyzing = SplitVectorOperand(N, i); 299 Changed = true; 300 break; 301 case WidenVector: 302 NeedsReanalyzing = WidenVectorOperand(N, i); 303 Changed = true; 304 break; 305 } 306 break; 307 } 308 309 // The sub-method updated N in place. Check to see if any operands are new, 310 // and if so, mark them. If the node needs revisiting, don't add all users 311 // to the worklist etc. 312 if (NeedsReanalyzing) { 313 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 314 N->setNodeId(NewNode); 315 // Recompute the NodeId and correct processed operands, adding the node to 316 // the worklist if ready. 317 SDNode *M = AnalyzeNewNode(N); 318 if (M == N) 319 // The node didn't morph - nothing special to do, it will be revisited. 320 continue; 321 322 // The node morphed - this is equivalent to legalizing by replacing every 323 // value of N with the corresponding value of M. So do that now. However 324 // there is no need to remember the replacement - morphing will make sure 325 // it is never used non-trivially. 326 assert(N->getNumValues() == M->getNumValues() && 327 "Node morphing changed the number of results!"); 328 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 329 // Replacing the value takes care of remapping the new value. Do the 330 // replacement without recording it in ReplacedValues. This does not 331 // expunge From but that is fine - it is not really a new node. 332 ReplaceValueWithHelper(SDValue(N, i), SDValue(M, i)); 333 assert(N->getNodeId() == NewNode && "Unexpected node state!"); 334 // The node continues to live on as part of the NewNode fungus that 335 // grows on top of the useful nodes. Nothing more needs to be done 336 // with it - move on to the next node. 337 continue; 338 } 339 340 if (i == NumOperands) { 341 DEBUG(errs() << "Legally typed node: "; N->dump(&DAG); errs() << "\n"); 342 } 343 } 344NodeDone: 345 346 // If we reach here, the node was processed, potentially creating new nodes. 347 // Mark it as processed and add its users to the worklist as appropriate. 348 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 349 N->setNodeId(Processed); 350 351 for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end(); 352 UI != E; ++UI) { 353 SDNode *User = *UI; 354 int NodeId = User->getNodeId(); 355 356 // This node has two options: it can either be a new node or its Node ID 357 // may be a count of the number of operands it has that are not ready. 358 if (NodeId > 0) { 359 User->setNodeId(NodeId-1); 360 361 // If this was the last use it was waiting on, add it to the ready list. 362 if (NodeId-1 == ReadyToProcess) 363 Worklist.push_back(User); 364 continue; 365 } 366 367 // If this is an unreachable new node, then ignore it. If it ever becomes 368 // reachable by being used by a newly created node then it will be handled 369 // by AnalyzeNewNode. 370 if (NodeId == NewNode) 371 continue; 372 373 // Otherwise, this node is new: this is the first operand of it that 374 // became ready. Its new NodeId is the number of operands it has minus 1 375 // (as this node is now processed). 376 assert(NodeId == Unanalyzed && "Unknown node ID!"); 377 User->setNodeId(User->getNumOperands() - 1); 378 379 // If the node only has a single operand, it is now ready. 380 if (User->getNumOperands() == 1) 381 Worklist.push_back(User); 382 } 383 } 384 385#ifndef XDEBUG 386 if (EnableExpensiveChecks) 387#endif 388 PerformExpensiveChecks(); 389 390 // If the root changed (e.g. it was a dead load) update the root. 391 DAG.setRoot(Dummy.getValue()); 392 393 // Remove dead nodes. This is important to do for cleanliness but also before 394 // the checking loop below. Implicit folding by the DAG.getNode operators and 395 // node morphing can cause unreachable nodes to be around with their flags set 396 // to new. 397 DAG.RemoveDeadNodes(); 398 399 // In a debug build, scan all the nodes to make sure we found them all. This 400 // ensures that there are no cycles and that everything got processed. 401#ifndef NDEBUG 402 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 403 E = DAG.allnodes_end(); I != E; ++I) { 404 bool Failed = false; 405 406 // Check that all result types are legal. 407 if (!IgnoreNodeResults(I)) 408 for (unsigned i = 0, NumVals = I->getNumValues(); i < NumVals; ++i) 409 if (!isTypeLegal(I->getValueType(i))) { 410 errs() << "Result type " << i << " illegal!\n"; 411 Failed = true; 412 } 413 414 // Check that all operand types are legal. 415 for (unsigned i = 0, NumOps = I->getNumOperands(); i < NumOps; ++i) 416 if (!IgnoreNodeResults(I->getOperand(i).getNode()) && 417 !isTypeLegal(I->getOperand(i).getValueType())) { 418 errs() << "Operand type " << i << " illegal!\n"; 419 Failed = true; 420 } 421 422 if (I->getNodeId() != Processed) { 423 if (I->getNodeId() == NewNode) 424 errs() << "New node not analyzed?\n"; 425 else if (I->getNodeId() == Unanalyzed) 426 errs() << "Unanalyzed node not noticed?\n"; 427 else if (I->getNodeId() > 0) 428 errs() << "Operand not processed?\n"; 429 else if (I->getNodeId() == ReadyToProcess) 430 errs() << "Not added to worklist?\n"; 431 Failed = true; 432 } 433 434 if (Failed) { 435 I->dump(&DAG); errs() << "\n"; 436 llvm_unreachable(0); 437 } 438 } 439#endif 440 441 return Changed; 442} 443 444/// AnalyzeNewNode - The specified node is the root of a subtree of potentially 445/// new nodes. Correct any processed operands (this may change the node) and 446/// calculate the NodeId. If the node itself changes to a processed node, it 447/// is not remapped - the caller needs to take care of this. 448/// Returns the potentially changed node. 449SDNode *DAGTypeLegalizer::AnalyzeNewNode(SDNode *N) { 450 // If this was an existing node that is already done, we're done. 451 if (N->getNodeId() != NewNode && N->getNodeId() != Unanalyzed) 452 return N; 453 454 // Remove any stale map entries. 455 ExpungeNode(N); 456 457 // Okay, we know that this node is new. Recursively walk all of its operands 458 // to see if they are new also. The depth of this walk is bounded by the size 459 // of the new tree that was constructed (usually 2-3 nodes), so we don't worry 460 // about revisiting of nodes. 461 // 462 // As we walk the operands, keep track of the number of nodes that are 463 // processed. If non-zero, this will become the new nodeid of this node. 464 // Operands may morph when they are analyzed. If so, the node will be 465 // updated after all operands have been analyzed. Since this is rare, 466 // the code tries to minimize overhead in the non-morphing case. 467 468 SmallVector<SDValue, 8> NewOps; 469 unsigned NumProcessed = 0; 470 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) { 471 SDValue OrigOp = N->getOperand(i); 472 SDValue Op = OrigOp; 473 474 AnalyzeNewValue(Op); // Op may morph. 475 476 if (Op.getNode()->getNodeId() == Processed) 477 ++NumProcessed; 478 479 if (!NewOps.empty()) { 480 // Some previous operand changed. Add this one to the list. 481 NewOps.push_back(Op); 482 } else if (Op != OrigOp) { 483 // This is the first operand to change - add all operands so far. 484 NewOps.insert(NewOps.end(), N->op_begin(), N->op_begin() + i); 485 NewOps.push_back(Op); 486 } 487 } 488 489 // Some operands changed - update the node. 490 if (!NewOps.empty()) { 491 SDNode *M = DAG.UpdateNodeOperands(SDValue(N, 0), &NewOps[0], 492 NewOps.size()).getNode(); 493 if (M != N) { 494 // The node morphed into a different node. Normally for this to happen 495 // the original node would have to be marked NewNode. However this can 496 // in theory momentarily not be the case while ReplaceValueWith is doing 497 // its stuff. Mark the original node NewNode to help sanity checking. 498 N->setNodeId(NewNode); 499 if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed) 500 // It morphed into a previously analyzed node - nothing more to do. 501 return M; 502 503 // It morphed into a different new node. Do the equivalent of passing 504 // it to AnalyzeNewNode: expunge it and calculate the NodeId. No need 505 // to remap the operands, since they are the same as the operands we 506 // remapped above. 507 N = M; 508 ExpungeNode(N); 509 } 510 } 511 512 // Calculate the NodeId. 513 N->setNodeId(N->getNumOperands() - NumProcessed); 514 if (N->getNodeId() == ReadyToProcess) 515 Worklist.push_back(N); 516 517 return N; 518} 519 520/// AnalyzeNewValue - Call AnalyzeNewNode, updating the node in Val if needed. 521/// If the node changes to a processed node, then remap it. 522void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) { 523 Val.setNode(AnalyzeNewNode(Val.getNode())); 524 if (Val.getNode()->getNodeId() == Processed) 525 // We were passed a processed node, or it morphed into one - remap it. 526 RemapValue(Val); 527} 528 529/// ExpungeNode - If N has a bogus mapping in ReplacedValues, eliminate it. 530/// This can occur when a node is deleted then reallocated as a new node - 531/// the mapping in ReplacedValues applies to the deleted node, not the new 532/// one. 533/// The only map that can have a deleted node as a source is ReplacedValues. 534/// Other maps can have deleted nodes as targets, but since their looked-up 535/// values are always immediately remapped using RemapValue, resulting in a 536/// not-deleted node, this is harmless as long as ReplacedValues/RemapValue 537/// always performs correct mappings. In order to keep the mapping correct, 538/// ExpungeNode should be called on any new nodes *before* adding them as 539/// either source or target to ReplacedValues (which typically means calling 540/// Expunge when a new node is first seen, since it may no longer be marked 541/// NewNode by the time it is added to ReplacedValues). 542void DAGTypeLegalizer::ExpungeNode(SDNode *N) { 543 if (N->getNodeId() != NewNode) 544 return; 545 546 // If N is not remapped by ReplacedValues then there is nothing to do. 547 unsigned i, e; 548 for (i = 0, e = N->getNumValues(); i != e; ++i) 549 if (ReplacedValues.find(SDValue(N, i)) != ReplacedValues.end()) 550 break; 551 552 if (i == e) 553 return; 554 555 // Remove N from all maps - this is expensive but rare. 556 557 for (DenseMap<SDValue, SDValue>::iterator I = PromotedIntegers.begin(), 558 E = PromotedIntegers.end(); I != E; ++I) { 559 assert(I->first.getNode() != N); 560 RemapValue(I->second); 561 } 562 563 for (DenseMap<SDValue, SDValue>::iterator I = SoftenedFloats.begin(), 564 E = SoftenedFloats.end(); I != E; ++I) { 565 assert(I->first.getNode() != N); 566 RemapValue(I->second); 567 } 568 569 for (DenseMap<SDValue, SDValue>::iterator I = ScalarizedVectors.begin(), 570 E = ScalarizedVectors.end(); I != E; ++I) { 571 assert(I->first.getNode() != N); 572 RemapValue(I->second); 573 } 574 575 for (DenseMap<SDValue, SDValue>::iterator I = WidenedVectors.begin(), 576 E = WidenedVectors.end(); I != E; ++I) { 577 assert(I->first.getNode() != N); 578 RemapValue(I->second); 579 } 580 581 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 582 I = ExpandedIntegers.begin(), E = ExpandedIntegers.end(); I != E; ++I){ 583 assert(I->first.getNode() != N); 584 RemapValue(I->second.first); 585 RemapValue(I->second.second); 586 } 587 588 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 589 I = ExpandedFloats.begin(), E = ExpandedFloats.end(); I != E; ++I) { 590 assert(I->first.getNode() != N); 591 RemapValue(I->second.first); 592 RemapValue(I->second.second); 593 } 594 595 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 596 I = SplitVectors.begin(), E = SplitVectors.end(); I != E; ++I) { 597 assert(I->first.getNode() != N); 598 RemapValue(I->second.first); 599 RemapValue(I->second.second); 600 } 601 602 for (DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.begin(), 603 E = ReplacedValues.end(); I != E; ++I) 604 RemapValue(I->second); 605 606 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 607 ReplacedValues.erase(SDValue(N, i)); 608} 609 610/// RemapValue - If the specified value was already legalized to another value, 611/// replace it by that value. 612void DAGTypeLegalizer::RemapValue(SDValue &N) { 613 DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(N); 614 if (I != ReplacedValues.end()) { 615 // Use path compression to speed up future lookups if values get multiply 616 // replaced with other values. 617 RemapValue(I->second); 618 N = I->second; 619 assert(N.getNode()->getNodeId() != NewNode && "Mapped to new node!"); 620 } 621} 622 623namespace { 624 /// NodeUpdateListener - This class is a DAGUpdateListener that listens for 625 /// updates to nodes and recomputes their ready state. 626 class VISIBILITY_HIDDEN NodeUpdateListener : 627 public SelectionDAG::DAGUpdateListener { 628 DAGTypeLegalizer &DTL; 629 SmallSetVector<SDNode*, 16> &NodesToAnalyze; 630 public: 631 explicit NodeUpdateListener(DAGTypeLegalizer &dtl, 632 SmallSetVector<SDNode*, 16> &nta) 633 : DTL(dtl), NodesToAnalyze(nta) {} 634 635 virtual void NodeDeleted(SDNode *N, SDNode *E) { 636 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 637 N->getNodeId() != DAGTypeLegalizer::Processed && 638 "Invalid node ID for RAUW deletion!"); 639 // It is possible, though rare, for the deleted node N to occur as a 640 // target in a map, so note the replacement N -> E in ReplacedValues. 641 assert(E && "Node not replaced?"); 642 DTL.NoteDeletion(N, E); 643 644 // In theory the deleted node could also have been scheduled for analysis. 645 // So remove it from the set of nodes which will be analyzed. 646 NodesToAnalyze.remove(N); 647 648 // In general nothing needs to be done for E, since it didn't change but 649 // only gained new uses. However N -> E was just added to ReplacedValues, 650 // and the result of a ReplacedValues mapping is not allowed to be marked 651 // NewNode. So if E is marked NewNode, then it needs to be analyzed. 652 if (E->getNodeId() == DAGTypeLegalizer::NewNode) 653 NodesToAnalyze.insert(E); 654 } 655 656 virtual void NodeUpdated(SDNode *N) { 657 // Node updates can mean pretty much anything. It is possible that an 658 // operand was set to something already processed (f.e.) in which case 659 // this node could become ready. Recompute its flags. 660 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 661 N->getNodeId() != DAGTypeLegalizer::Processed && 662 "Invalid node ID for RAUW deletion!"); 663 N->setNodeId(DAGTypeLegalizer::NewNode); 664 NodesToAnalyze.insert(N); 665 } 666 }; 667} 668 669 670/// ReplaceValueWithHelper - Internal helper for ReplaceValueWith. Updates the 671/// DAG causing any uses of From to use To instead, but without expunging From 672/// or recording the replacement in ReplacedValues. Do not call directly unless 673/// you really know what you are doing! 674void DAGTypeLegalizer::ReplaceValueWithHelper(SDValue From, SDValue To) { 675 assert(From.getNode() != To.getNode() && "Potential legalization loop!"); 676 677 // If expansion produced new nodes, make sure they are properly marked. 678 AnalyzeNewValue(To); // Expunges To. 679 680 // Anything that used the old node should now use the new one. Note that this 681 // can potentially cause recursive merging. 682 SmallSetVector<SDNode*, 16> NodesToAnalyze; 683 NodeUpdateListener NUL(*this, NodesToAnalyze); 684 DAG.ReplaceAllUsesOfValueWith(From, To, &NUL); 685 686 // Process the list of nodes that need to be reanalyzed. 687 while (!NodesToAnalyze.empty()) { 688 SDNode *N = NodesToAnalyze.back(); 689 NodesToAnalyze.pop_back(); 690 if (N->getNodeId() != DAGTypeLegalizer::NewNode) 691 // The node was analyzed while reanalyzing an earlier node - it is safe to 692 // skip. Note that this is not a morphing node - otherwise it would still 693 // be marked NewNode. 694 continue; 695 696 // Analyze the node's operands and recalculate the node ID. 697 SDNode *M = AnalyzeNewNode(N); 698 if (M != N) { 699 // The node morphed into a different node. Make everyone use the new node 700 // instead. 701 assert(M->getNodeId() != NewNode && "Analysis resulted in NewNode!"); 702 assert(N->getNumValues() == M->getNumValues() && 703 "Node morphing changed the number of results!"); 704 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) { 705 SDValue OldVal(N, i); 706 SDValue NewVal(M, i); 707 if (M->getNodeId() == Processed) 708 RemapValue(NewVal); 709 DAG.ReplaceAllUsesOfValueWith(OldVal, NewVal, &NUL); 710 } 711 // The original node continues to exist in the DAG, marked NewNode. 712 } 713 } 714} 715 716/// ReplaceValueWith - The specified value was legalized to the specified other 717/// value. Update the DAG and NodeIds replacing any uses of From to use To 718/// instead. 719void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) { 720 assert(From.getNode()->getNodeId() == ReadyToProcess && 721 "Only the node being processed may be remapped!"); 722 723 // If expansion produced new nodes, make sure they are properly marked. 724 ExpungeNode(From.getNode()); 725 AnalyzeNewValue(To); // Expunges To. 726 727 // The old node may still be present in a map like ExpandedIntegers or 728 // PromotedIntegers. Inform maps about the replacement. 729 ReplacedValues[From] = To; 730 731 // Do the replacement. 732 ReplaceValueWithHelper(From, To); 733} 734 735void DAGTypeLegalizer::SetPromotedInteger(SDValue Op, SDValue Result) { 736 assert(Result.getValueType() == TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 737 "Invalid type for promoted integer"); 738 AnalyzeNewValue(Result); 739 740 SDValue &OpEntry = PromotedIntegers[Op]; 741 assert(OpEntry.getNode() == 0 && "Node is already promoted!"); 742 OpEntry = Result; 743} 744 745void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) { 746 assert(Result.getValueType() == TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 747 "Invalid type for softened float"); 748 AnalyzeNewValue(Result); 749 750 SDValue &OpEntry = SoftenedFloats[Op]; 751 assert(OpEntry.getNode() == 0 && "Node is already converted to integer!"); 752 OpEntry = Result; 753} 754 755void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) { 756 assert(Result.getValueType() == Op.getValueType().getVectorElementType() && 757 "Invalid type for scalarized vector"); 758 AnalyzeNewValue(Result); 759 760 SDValue &OpEntry = ScalarizedVectors[Op]; 761 assert(OpEntry.getNode() == 0 && "Node is already scalarized!"); 762 OpEntry = Result; 763} 764 765void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo, 766 SDValue &Hi) { 767 std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op]; 768 RemapValue(Entry.first); 769 RemapValue(Entry.second); 770 assert(Entry.first.getNode() && "Operand isn't expanded"); 771 Lo = Entry.first; 772 Hi = Entry.second; 773} 774 775void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo, 776 SDValue Hi) { 777 assert(Lo.getValueType() == TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 778 Hi.getValueType() == Lo.getValueType() && 779 "Invalid type for expanded integer"); 780 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 781 AnalyzeNewValue(Lo); 782 AnalyzeNewValue(Hi); 783 784 // Remember that this is the result of the node. 785 std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op]; 786 assert(Entry.first.getNode() == 0 && "Node already expanded"); 787 Entry.first = Lo; 788 Entry.second = Hi; 789} 790 791void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo, 792 SDValue &Hi) { 793 std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op]; 794 RemapValue(Entry.first); 795 RemapValue(Entry.second); 796 assert(Entry.first.getNode() && "Operand isn't expanded"); 797 Lo = Entry.first; 798 Hi = Entry.second; 799} 800 801void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo, 802 SDValue Hi) { 803 assert(Lo.getValueType() == TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 804 Hi.getValueType() == Lo.getValueType() && 805 "Invalid type for expanded float"); 806 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 807 AnalyzeNewValue(Lo); 808 AnalyzeNewValue(Hi); 809 810 // Remember that this is the result of the node. 811 std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op]; 812 assert(Entry.first.getNode() == 0 && "Node already expanded"); 813 Entry.first = Lo; 814 Entry.second = Hi; 815} 816 817void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo, 818 SDValue &Hi) { 819 std::pair<SDValue, SDValue> &Entry = SplitVectors[Op]; 820 RemapValue(Entry.first); 821 RemapValue(Entry.second); 822 assert(Entry.first.getNode() && "Operand isn't split"); 823 Lo = Entry.first; 824 Hi = Entry.second; 825} 826 827void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo, 828 SDValue Hi) { 829 assert(Lo.getValueType().getVectorElementType() == 830 Op.getValueType().getVectorElementType() && 831 2*Lo.getValueType().getVectorNumElements() == 832 Op.getValueType().getVectorNumElements() && 833 Hi.getValueType() == Lo.getValueType() && 834 "Invalid type for split vector"); 835 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 836 AnalyzeNewValue(Lo); 837 AnalyzeNewValue(Hi); 838 839 // Remember that this is the result of the node. 840 std::pair<SDValue, SDValue> &Entry = SplitVectors[Op]; 841 assert(Entry.first.getNode() == 0 && "Node already split"); 842 Entry.first = Lo; 843 Entry.second = Hi; 844} 845 846void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) { 847 assert(Result.getValueType() == TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 848 "Invalid type for widened vector"); 849 AnalyzeNewValue(Result); 850 851 SDValue &OpEntry = WidenedVectors[Op]; 852 assert(OpEntry.getNode() == 0 && "Node already widened!"); 853 OpEntry = Result; 854} 855 856 857//===----------------------------------------------------------------------===// 858// Utilities. 859//===----------------------------------------------------------------------===// 860 861/// BitConvertToInteger - Convert to an integer of the same size. 862SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) { 863 unsigned BitWidth = Op.getValueType().getSizeInBits(); 864 return DAG.getNode(ISD::BIT_CONVERT, Op.getDebugLoc(), 865 EVT::getIntegerVT(*DAG.getContext(), BitWidth), Op); 866} 867 868/// BitConvertVectorToIntegerVector - Convert to a vector of integers of the 869/// same size. 870SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) { 871 assert(Op.getValueType().isVector() && "Only applies to vectors!"); 872 unsigned EltWidth = Op.getValueType().getVectorElementType().getSizeInBits(); 873 EVT EltNVT = EVT::getIntegerVT(*DAG.getContext(), EltWidth); 874 unsigned NumElts = Op.getValueType().getVectorNumElements(); 875 return DAG.getNode(ISD::BIT_CONVERT, Op.getDebugLoc(), 876 EVT::getVectorVT(*DAG.getContext(), EltNVT, NumElts), Op); 877} 878 879SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op, 880 EVT DestVT) { 881 DebugLoc dl = Op.getDebugLoc(); 882 // Create the stack frame object. Make sure it is aligned for both 883 // the source and destination types. 884 SDValue StackPtr = DAG.CreateStackTemporary(Op.getValueType(), DestVT); 885 // Emit a store to the stack slot. 886 SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Op, StackPtr, NULL, 0); 887 // Result is a load from the stack slot. 888 return DAG.getLoad(DestVT, dl, Store, StackPtr, NULL, 0); 889} 890 891/// CustomLowerNode - Replace the node's results with custom code provided 892/// by the target and return "true", or do nothing and return "false". 893/// The last parameter is FALSE if we are dealing with a node with legal 894/// result types and illegal operand. The second parameter denotes the type of 895/// illegal OperandNo in that case. 896/// The last parameter being TRUE means we are dealing with a 897/// node with illegal result types. The second parameter denotes the type of 898/// illegal ResNo in that case. 899bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) { 900 // See if the target wants to custom lower this node. 901 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom) 902 return false; 903 904 SmallVector<SDValue, 8> Results; 905 if (LegalizeResult) 906 TLI.ReplaceNodeResults(N, Results, DAG); 907 else 908 TLI.LowerOperationWrapper(N, Results, DAG); 909 910 if (Results.empty()) 911 // The target didn't want to custom lower it after all. 912 return false; 913 914 // Make everything that once used N's values now use those in Results instead. 915 assert(Results.size() == N->getNumValues() && 916 "Custom lowering returned the wrong number of results!"); 917 for (unsigned i = 0, e = Results.size(); i != e; ++i) 918 ReplaceValueWith(SDValue(N, i), Results[i]); 919 return true; 920} 921 922/// GetSplitDestVTs - Compute the VTs needed for the low/hi parts of a type 923/// which is split into two not necessarily identical pieces. 924void DAGTypeLegalizer::GetSplitDestVTs(EVT InVT, EVT &LoVT, EVT &HiVT) { 925 // Currently all types are split in half. 926 if (!InVT.isVector()) { 927 LoVT = HiVT = TLI.getTypeToTransformTo(*DAG.getContext(), InVT); 928 } else { 929 unsigned NumElements = InVT.getVectorNumElements(); 930 assert(!(NumElements & 1) && "Splitting vector, but not in half!"); 931 LoVT = HiVT = EVT::getVectorVT(*DAG.getContext(), InVT.getVectorElementType(), NumElements/2); 932 } 933} 934 935/// GetPairElements - Use ISD::EXTRACT_ELEMENT nodes to extract the low and 936/// high parts of the given value. 937void DAGTypeLegalizer::GetPairElements(SDValue Pair, 938 SDValue &Lo, SDValue &Hi) { 939 DebugLoc dl = Pair.getDebugLoc(); 940 EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), Pair.getValueType()); 941 Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair, 942 DAG.getIntPtrConstant(0)); 943 Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair, 944 DAG.getIntPtrConstant(1)); 945} 946 947SDValue DAGTypeLegalizer::GetVectorElementPointer(SDValue VecPtr, EVT EltVT, 948 SDValue Index) { 949 DebugLoc dl = Index.getDebugLoc(); 950 // Make sure the index type is big enough to compute in. 951 if (Index.getValueType().bitsGT(TLI.getPointerTy())) 952 Index = DAG.getNode(ISD::TRUNCATE, dl, TLI.getPointerTy(), Index); 953 else 954 Index = DAG.getNode(ISD::ZERO_EXTEND, dl, TLI.getPointerTy(), Index); 955 956 // Calculate the element offset and add it to the pointer. 957 unsigned EltSize = EltVT.getSizeInBits() / 8; // FIXME: should be ABI size. 958 959 Index = DAG.getNode(ISD::MUL, dl, Index.getValueType(), Index, 960 DAG.getConstant(EltSize, Index.getValueType())); 961 return DAG.getNode(ISD::ADD, dl, Index.getValueType(), Index, VecPtr); 962} 963 964/// JoinIntegers - Build an integer with low bits Lo and high bits Hi. 965SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) { 966 // Arbitrarily use dlHi for result DebugLoc 967 DebugLoc dlHi = Hi.getDebugLoc(); 968 DebugLoc dlLo = Lo.getDebugLoc(); 969 EVT LVT = Lo.getValueType(); 970 EVT HVT = Hi.getValueType(); 971 EVT NVT = EVT::getIntegerVT(*DAG.getContext(), LVT.getSizeInBits() + HVT.getSizeInBits()); 972 973 Lo = DAG.getNode(ISD::ZERO_EXTEND, dlLo, NVT, Lo); 974 Hi = DAG.getNode(ISD::ANY_EXTEND, dlHi, NVT, Hi); 975 Hi = DAG.getNode(ISD::SHL, dlHi, NVT, Hi, 976 DAG.getConstant(LVT.getSizeInBits(), TLI.getPointerTy())); 977 return DAG.getNode(ISD::OR, dlHi, NVT, Lo, Hi); 978} 979 980/// LibCallify - Convert the node into a libcall with the same prototype. 981SDValue DAGTypeLegalizer::LibCallify(RTLIB::Libcall LC, SDNode *N, 982 bool isSigned) { 983 unsigned NumOps = N->getNumOperands(); 984 DebugLoc dl = N->getDebugLoc(); 985 if (NumOps == 0) { 986 return MakeLibCall(LC, N->getValueType(0), 0, 0, isSigned, dl); 987 } else if (NumOps == 1) { 988 SDValue Op = N->getOperand(0); 989 return MakeLibCall(LC, N->getValueType(0), &Op, 1, isSigned, dl); 990 } else if (NumOps == 2) { 991 SDValue Ops[2] = { N->getOperand(0), N->getOperand(1) }; 992 return MakeLibCall(LC, N->getValueType(0), Ops, 2, isSigned, dl); 993 } 994 SmallVector<SDValue, 8> Ops(NumOps); 995 for (unsigned i = 0; i < NumOps; ++i) 996 Ops[i] = N->getOperand(i); 997 998 return MakeLibCall(LC, N->getValueType(0), &Ops[0], NumOps, isSigned, dl); 999} 1000 1001/// MakeLibCall - Generate a libcall taking the given operands as arguments and 1002/// returning a result of type RetVT. 1003SDValue DAGTypeLegalizer::MakeLibCall(RTLIB::Libcall LC, EVT RetVT, 1004 const SDValue *Ops, unsigned NumOps, 1005 bool isSigned, DebugLoc dl) { 1006 TargetLowering::ArgListTy Args; 1007 Args.reserve(NumOps); 1008 1009 TargetLowering::ArgListEntry Entry; 1010 for (unsigned i = 0; i != NumOps; ++i) { 1011 Entry.Node = Ops[i]; 1012 Entry.Ty = Entry.Node.getValueType().getTypeForEVT(*DAG.getContext()); 1013 Entry.isSExt = isSigned; 1014 Entry.isZExt = !isSigned; 1015 Args.push_back(Entry); 1016 } 1017 SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC), 1018 TLI.getPointerTy()); 1019 1020 const Type *RetTy = RetVT.getTypeForEVT(*DAG.getContext()); 1021 std::pair<SDValue,SDValue> CallInfo = 1022 TLI.LowerCallTo(DAG.getEntryNode(), RetTy, isSigned, !isSigned, false, 1023 false, 0, TLI.getLibcallCallingConv(LC), false, 1024 /*isReturnValueUsed=*/true, 1025 Callee, Args, DAG, dl); 1026 return CallInfo.first; 1027} 1028 1029/// PromoteTargetBoolean - Promote the given target boolean to a target boolean 1030/// of the given type. A target boolean is an integer value, not necessarily of 1031/// type i1, the bits of which conform to getBooleanContents. 1032SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT VT) { 1033 DebugLoc dl = Bool.getDebugLoc(); 1034 ISD::NodeType ExtendCode; 1035 switch (TLI.getBooleanContents()) { 1036 default: 1037 assert(false && "Unknown BooleanContent!"); 1038 case TargetLowering::UndefinedBooleanContent: 1039 // Extend to VT by adding rubbish bits. 1040 ExtendCode = ISD::ANY_EXTEND; 1041 break; 1042 case TargetLowering::ZeroOrOneBooleanContent: 1043 // Extend to VT by adding zero bits. 1044 ExtendCode = ISD::ZERO_EXTEND; 1045 break; 1046 case TargetLowering::ZeroOrNegativeOneBooleanContent: { 1047 // Extend to VT by copying the sign bit. 1048 ExtendCode = ISD::SIGN_EXTEND; 1049 break; 1050 } 1051 } 1052 return DAG.getNode(ExtendCode, dl, VT, Bool); 1053} 1054 1055/// SplitInteger - Return the lower LoVT bits of Op in Lo and the upper HiVT 1056/// bits in Hi. 1057void DAGTypeLegalizer::SplitInteger(SDValue Op, 1058 EVT LoVT, EVT HiVT, 1059 SDValue &Lo, SDValue &Hi) { 1060 DebugLoc dl = Op.getDebugLoc(); 1061 assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() == 1062 Op.getValueType().getSizeInBits() && "Invalid integer splitting!"); 1063 Lo = DAG.getNode(ISD::TRUNCATE, dl, LoVT, Op); 1064 Hi = DAG.getNode(ISD::SRL, dl, Op.getValueType(), Op, 1065 DAG.getConstant(LoVT.getSizeInBits(), TLI.getPointerTy())); 1066 Hi = DAG.getNode(ISD::TRUNCATE, dl, HiVT, Hi); 1067} 1068 1069/// SplitInteger - Return the lower and upper halves of Op's bits in a value 1070/// type half the size of Op's. 1071void DAGTypeLegalizer::SplitInteger(SDValue Op, 1072 SDValue &Lo, SDValue &Hi) { 1073 EVT HalfVT = EVT::getIntegerVT(*DAG.getContext(), Op.getValueType().getSizeInBits()/2); 1074 SplitInteger(Op, HalfVT, HalfVT, Lo, Hi); 1075} 1076 1077 1078//===----------------------------------------------------------------------===// 1079// Entry Point 1080//===----------------------------------------------------------------------===// 1081 1082/// LegalizeTypes - This transforms the SelectionDAG into a SelectionDAG that 1083/// only uses types natively supported by the target. Returns "true" if it made 1084/// any changes. 1085/// 1086/// Note that this is an involved process that may invalidate pointers into 1087/// the graph. 1088bool SelectionDAG::LegalizeTypes() { 1089 return DAGTypeLegalizer(*this).run(); 1090} 1091