LegalizeTypes.cpp revision 207618
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 never dereference deleted nodes). This means that it may 69 // also map nodes marked NewNode if the deallocated memory was reallocated as 70 // another node, and that new node was not seen by the LegalizeTypes machinery 71 // (for example because it was created but not used). In general, we cannot 72 // distinguish between new nodes and deleted nodes. 73 SmallVector<SDNode*, 16> NewNodes; 74 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 75 E = DAG.allnodes_end(); I != E; ++I) { 76 // Remember nodes marked NewNode - they are subject to extra checking below. 77 if (I->getNodeId() == NewNode) 78 NewNodes.push_back(I); 79 80 for (unsigned i = 0, e = I->getNumValues(); i != e; ++i) { 81 SDValue Res(I, i); 82 bool Failed = false; 83 84 unsigned Mapped = 0; 85 if (ReplacedValues.find(Res) != ReplacedValues.end()) { 86 Mapped |= 1; 87 // Check that remapped values are only used by nodes marked NewNode. 88 for (SDNode::use_iterator UI = I->use_begin(), UE = I->use_end(); 89 UI != UE; ++UI) 90 if (UI.getUse().getResNo() == i) 91 assert(UI->getNodeId() == NewNode && 92 "Remapped value has non-trivial use!"); 93 94 // Check that the final result of applying ReplacedValues is not 95 // marked NewNode. 96 SDValue NewVal = ReplacedValues[Res]; 97 DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(NewVal); 98 while (I != ReplacedValues.end()) { 99 NewVal = I->second; 100 I = ReplacedValues.find(NewVal); 101 } 102 assert(NewVal.getNode()->getNodeId() != NewNode && 103 "ReplacedValues maps to a new node!"); 104 } 105 if (PromotedIntegers.find(Res) != PromotedIntegers.end()) 106 Mapped |= 2; 107 if (SoftenedFloats.find(Res) != SoftenedFloats.end()) 108 Mapped |= 4; 109 if (ScalarizedVectors.find(Res) != ScalarizedVectors.end()) 110 Mapped |= 8; 111 if (ExpandedIntegers.find(Res) != ExpandedIntegers.end()) 112 Mapped |= 16; 113 if (ExpandedFloats.find(Res) != ExpandedFloats.end()) 114 Mapped |= 32; 115 if (SplitVectors.find(Res) != SplitVectors.end()) 116 Mapped |= 64; 117 if (WidenedVectors.find(Res) != WidenedVectors.end()) 118 Mapped |= 128; 119 120 if (I->getNodeId() != Processed) { 121 // Since we allow ReplacedValues to map deleted nodes, it may map nodes 122 // marked NewNode too, since a deleted node may have been reallocated as 123 // another node that has not been seen by the LegalizeTypes machinery. 124 if ((I->getNodeId() == NewNode && Mapped > 1) || 125 (I->getNodeId() != NewNode && Mapped != 0)) { 126 dbgs() << "Unprocessed value in a map!"; 127 Failed = true; 128 } 129 } else if (isTypeLegal(Res.getValueType()) || IgnoreNodeResults(I)) { 130 if (Mapped > 1) { 131 dbgs() << "Value with legal type was transformed!"; 132 Failed = true; 133 } 134 } else { 135 if (Mapped == 0) { 136 dbgs() << "Processed value not in any map!"; 137 Failed = true; 138 } else if (Mapped & (Mapped - 1)) { 139 dbgs() << "Value in multiple maps!"; 140 Failed = true; 141 } 142 } 143 144 if (Failed) { 145 if (Mapped & 1) 146 dbgs() << " ReplacedValues"; 147 if (Mapped & 2) 148 dbgs() << " PromotedIntegers"; 149 if (Mapped & 4) 150 dbgs() << " SoftenedFloats"; 151 if (Mapped & 8) 152 dbgs() << " ScalarizedVectors"; 153 if (Mapped & 16) 154 dbgs() << " ExpandedIntegers"; 155 if (Mapped & 32) 156 dbgs() << " ExpandedFloats"; 157 if (Mapped & 64) 158 dbgs() << " SplitVectors"; 159 if (Mapped & 128) 160 dbgs() << " WidenedVectors"; 161 dbgs() << "\n"; 162 llvm_unreachable(0); 163 } 164 } 165 } 166 167 // Checked that NewNodes are only used by other NewNodes. 168 for (unsigned i = 0, e = NewNodes.size(); i != e; ++i) { 169 SDNode *N = NewNodes[i]; 170 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 171 UI != UE; ++UI) 172 assert(UI->getNodeId() == NewNode && "NewNode used by non-NewNode!"); 173 } 174} 175 176/// run - This is the main entry point for the type legalizer. This does a 177/// top-down traversal of the dag, legalizing types as it goes. Returns "true" 178/// if it made any changes. 179bool DAGTypeLegalizer::run() { 180 bool Changed = false; 181 182 // Create a dummy node (which is not added to allnodes), that adds a reference 183 // to the root node, preventing it from being deleted, and tracking any 184 // changes of the root. 185 HandleSDNode Dummy(DAG.getRoot()); 186 Dummy.setNodeId(Unanalyzed); 187 188 // The root of the dag may dangle to deleted nodes until the type legalizer is 189 // done. Set it to null to avoid confusion. 190 DAG.setRoot(SDValue()); 191 192 // Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess' 193 // (and remembering them) if they are leaves and assigning 'Unanalyzed' if 194 // non-leaves. 195 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 196 E = DAG.allnodes_end(); I != E; ++I) { 197 if (I->getNumOperands() == 0) { 198 I->setNodeId(ReadyToProcess); 199 Worklist.push_back(I); 200 } else { 201 I->setNodeId(Unanalyzed); 202 } 203 } 204 205 // Now that we have a set of nodes to process, handle them all. 206 while (!Worklist.empty()) { 207#ifndef XDEBUG 208 if (EnableExpensiveChecks) 209#endif 210 PerformExpensiveChecks(); 211 212 SDNode *N = Worklist.back(); 213 Worklist.pop_back(); 214 assert(N->getNodeId() == ReadyToProcess && 215 "Node should be ready if on worklist!"); 216 217 if (IgnoreNodeResults(N)) 218 goto ScanOperands; 219 220 // Scan the values produced by the node, checking to see if any result 221 // types are illegal. 222 for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) { 223 EVT ResultVT = N->getValueType(i); 224 switch (getTypeAction(ResultVT)) { 225 default: 226 assert(false && "Unknown action!"); 227 case Legal: 228 break; 229 // The following calls must take care of *all* of the node's results, 230 // not just the illegal result they were passed (this includes results 231 // with a legal type). Results can be remapped using ReplaceValueWith, 232 // or their promoted/expanded/etc values registered in PromotedIntegers, 233 // ExpandedIntegers etc. 234 case PromoteInteger: 235 PromoteIntegerResult(N, i); 236 Changed = true; 237 goto NodeDone; 238 case ExpandInteger: 239 ExpandIntegerResult(N, i); 240 Changed = true; 241 goto NodeDone; 242 case SoftenFloat: 243 SoftenFloatResult(N, i); 244 Changed = true; 245 goto NodeDone; 246 case ExpandFloat: 247 ExpandFloatResult(N, i); 248 Changed = true; 249 goto NodeDone; 250 case ScalarizeVector: 251 ScalarizeVectorResult(N, i); 252 Changed = true; 253 goto NodeDone; 254 case SplitVector: 255 SplitVectorResult(N, i); 256 Changed = true; 257 goto NodeDone; 258 case WidenVector: 259 WidenVectorResult(N, i); 260 Changed = true; 261 goto NodeDone; 262 } 263 } 264 265ScanOperands: 266 // Scan the operand list for the node, handling any nodes with operands that 267 // are illegal. 268 { 269 unsigned NumOperands = N->getNumOperands(); 270 bool NeedsReanalyzing = false; 271 unsigned i; 272 for (i = 0; i != NumOperands; ++i) { 273 if (IgnoreNodeResults(N->getOperand(i).getNode())) 274 continue; 275 276 EVT OpVT = N->getOperand(i).getValueType(); 277 switch (getTypeAction(OpVT)) { 278 default: 279 assert(false && "Unknown action!"); 280 case Legal: 281 continue; 282 // The following calls must either replace all of the node's results 283 // using ReplaceValueWith, and return "false"; or update the node's 284 // operands in place, and return "true". 285 case PromoteInteger: 286 NeedsReanalyzing = PromoteIntegerOperand(N, i); 287 Changed = true; 288 break; 289 case ExpandInteger: 290 NeedsReanalyzing = ExpandIntegerOperand(N, i); 291 Changed = true; 292 break; 293 case SoftenFloat: 294 NeedsReanalyzing = SoftenFloatOperand(N, i); 295 Changed = true; 296 break; 297 case ExpandFloat: 298 NeedsReanalyzing = ExpandFloatOperand(N, i); 299 Changed = true; 300 break; 301 case ScalarizeVector: 302 NeedsReanalyzing = ScalarizeVectorOperand(N, i); 303 Changed = true; 304 break; 305 case SplitVector: 306 NeedsReanalyzing = SplitVectorOperand(N, i); 307 Changed = true; 308 break; 309 case WidenVector: 310 NeedsReanalyzing = WidenVectorOperand(N, i); 311 Changed = true; 312 break; 313 } 314 break; 315 } 316 317 // The sub-method updated N in place. Check to see if any operands are new, 318 // and if so, mark them. If the node needs revisiting, don't add all users 319 // to the worklist etc. 320 if (NeedsReanalyzing) { 321 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 322 N->setNodeId(NewNode); 323 // Recompute the NodeId and correct processed operands, adding the node to 324 // the worklist if ready. 325 SDNode *M = AnalyzeNewNode(N); 326 if (M == N) 327 // The node didn't morph - nothing special to do, it will be revisited. 328 continue; 329 330 // The node morphed - this is equivalent to legalizing by replacing every 331 // value of N with the corresponding value of M. So do that now. 332 assert(N->getNumValues() == M->getNumValues() && 333 "Node morphing changed the number of results!"); 334 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 335 // Replacing the value takes care of remapping the new value. 336 ReplaceValueWith(SDValue(N, i), SDValue(M, i)); 337 assert(N->getNodeId() == NewNode && "Unexpected node state!"); 338 // The node continues to live on as part of the NewNode fungus that 339 // grows on top of the useful nodes. Nothing more needs to be done 340 // with it - move on to the next node. 341 continue; 342 } 343 344 if (i == NumOperands) { 345 DEBUG(dbgs() << "Legally typed node: "; N->dump(&DAG); dbgs() << "\n"); 346 } 347 } 348NodeDone: 349 350 // If we reach here, the node was processed, potentially creating new nodes. 351 // Mark it as processed and add its users to the worklist as appropriate. 352 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 353 N->setNodeId(Processed); 354 355 for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end(); 356 UI != E; ++UI) { 357 SDNode *User = *UI; 358 int NodeId = User->getNodeId(); 359 360 // This node has two options: it can either be a new node or its Node ID 361 // may be a count of the number of operands it has that are not ready. 362 if (NodeId > 0) { 363 User->setNodeId(NodeId-1); 364 365 // If this was the last use it was waiting on, add it to the ready list. 366 if (NodeId-1 == ReadyToProcess) 367 Worklist.push_back(User); 368 continue; 369 } 370 371 // If this is an unreachable new node, then ignore it. If it ever becomes 372 // reachable by being used by a newly created node then it will be handled 373 // by AnalyzeNewNode. 374 if (NodeId == NewNode) 375 continue; 376 377 // Otherwise, this node is new: this is the first operand of it that 378 // became ready. Its new NodeId is the number of operands it has minus 1 379 // (as this node is now processed). 380 assert(NodeId == Unanalyzed && "Unknown node ID!"); 381 User->setNodeId(User->getNumOperands() - 1); 382 383 // If the node only has a single operand, it is now ready. 384 if (User->getNumOperands() == 1) 385 Worklist.push_back(User); 386 } 387 } 388 389#ifndef XDEBUG 390 if (EnableExpensiveChecks) 391#endif 392 PerformExpensiveChecks(); 393 394 // If the root changed (e.g. it was a dead load) update the root. 395 DAG.setRoot(Dummy.getValue()); 396 397 // Remove dead nodes. This is important to do for cleanliness but also before 398 // the checking loop below. Implicit folding by the DAG.getNode operators and 399 // node morphing can cause unreachable nodes to be around with their flags set 400 // to new. 401 DAG.RemoveDeadNodes(); 402 403 // In a debug build, scan all the nodes to make sure we found them all. This 404 // ensures that there are no cycles and that everything got processed. 405#ifndef NDEBUG 406 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 407 E = DAG.allnodes_end(); I != E; ++I) { 408 bool Failed = false; 409 410 // Check that all result types are legal. 411 if (!IgnoreNodeResults(I)) 412 for (unsigned i = 0, NumVals = I->getNumValues(); i < NumVals; ++i) 413 if (!isTypeLegal(I->getValueType(i))) { 414 dbgs() << "Result type " << i << " illegal!\n"; 415 Failed = true; 416 } 417 418 // Check that all operand types are legal. 419 for (unsigned i = 0, NumOps = I->getNumOperands(); i < NumOps; ++i) 420 if (!IgnoreNodeResults(I->getOperand(i).getNode()) && 421 !isTypeLegal(I->getOperand(i).getValueType())) { 422 dbgs() << "Operand type " << i << " illegal!\n"; 423 Failed = true; 424 } 425 426 if (I->getNodeId() != Processed) { 427 if (I->getNodeId() == NewNode) 428 dbgs() << "New node not analyzed?\n"; 429 else if (I->getNodeId() == Unanalyzed) 430 dbgs() << "Unanalyzed node not noticed?\n"; 431 else if (I->getNodeId() > 0) 432 dbgs() << "Operand not processed?\n"; 433 else if (I->getNodeId() == ReadyToProcess) 434 dbgs() << "Not added to worklist?\n"; 435 Failed = true; 436 } 437 438 if (Failed) { 439 I->dump(&DAG); dbgs() << "\n"; 440 llvm_unreachable(0); 441 } 442 } 443#endif 444 445 return Changed; 446} 447 448/// AnalyzeNewNode - The specified node is the root of a subtree of potentially 449/// new nodes. Correct any processed operands (this may change the node) and 450/// calculate the NodeId. If the node itself changes to a processed node, it 451/// is not remapped - the caller needs to take care of this. 452/// Returns the potentially changed node. 453SDNode *DAGTypeLegalizer::AnalyzeNewNode(SDNode *N) { 454 // If this was an existing node that is already done, we're done. 455 if (N->getNodeId() != NewNode && N->getNodeId() != Unanalyzed) 456 return N; 457 458 // Remove any stale map entries. 459 ExpungeNode(N); 460 461 // Okay, we know that this node is new. Recursively walk all of its operands 462 // to see if they are new also. The depth of this walk is bounded by the size 463 // of the new tree that was constructed (usually 2-3 nodes), so we don't worry 464 // about revisiting of nodes. 465 // 466 // As we walk the operands, keep track of the number of nodes that are 467 // processed. If non-zero, this will become the new nodeid of this node. 468 // Operands may morph when they are analyzed. If so, the node will be 469 // updated after all operands have been analyzed. Since this is rare, 470 // the code tries to minimize overhead in the non-morphing case. 471 472 SmallVector<SDValue, 8> NewOps; 473 unsigned NumProcessed = 0; 474 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) { 475 SDValue OrigOp = N->getOperand(i); 476 SDValue Op = OrigOp; 477 478 AnalyzeNewValue(Op); // Op may morph. 479 480 if (Op.getNode()->getNodeId() == Processed) 481 ++NumProcessed; 482 483 if (!NewOps.empty()) { 484 // Some previous operand changed. Add this one to the list. 485 NewOps.push_back(Op); 486 } else if (Op != OrigOp) { 487 // This is the first operand to change - add all operands so far. 488 NewOps.insert(NewOps.end(), N->op_begin(), N->op_begin() + i); 489 NewOps.push_back(Op); 490 } 491 } 492 493 // Some operands changed - update the node. 494 if (!NewOps.empty()) { 495 SDNode *M = DAG.UpdateNodeOperands(SDValue(N, 0), &NewOps[0], 496 NewOps.size()).getNode(); 497 if (M != N) { 498 // The node morphed into a different node. Normally for this to happen 499 // the original node would have to be marked NewNode. However this can 500 // in theory momentarily not be the case while ReplaceValueWith is doing 501 // its stuff. Mark the original node NewNode to help sanity checking. 502 N->setNodeId(NewNode); 503 if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed) 504 // It morphed into a previously analyzed node - nothing more to do. 505 return M; 506 507 // It morphed into a different new node. Do the equivalent of passing 508 // it to AnalyzeNewNode: expunge it and calculate the NodeId. No need 509 // to remap the operands, since they are the same as the operands we 510 // remapped above. 511 N = M; 512 ExpungeNode(N); 513 } 514 } 515 516 // Calculate the NodeId. 517 N->setNodeId(N->getNumOperands() - NumProcessed); 518 if (N->getNodeId() == ReadyToProcess) 519 Worklist.push_back(N); 520 521 return N; 522} 523 524/// AnalyzeNewValue - Call AnalyzeNewNode, updating the node in Val if needed. 525/// If the node changes to a processed node, then remap it. 526void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) { 527 Val.setNode(AnalyzeNewNode(Val.getNode())); 528 if (Val.getNode()->getNodeId() == Processed) 529 // We were passed a processed node, or it morphed into one - remap it. 530 RemapValue(Val); 531} 532 533/// ExpungeNode - If N has a bogus mapping in ReplacedValues, eliminate it. 534/// This can occur when a node is deleted then reallocated as a new node - 535/// the mapping in ReplacedValues applies to the deleted node, not the new 536/// one. 537/// The only map that can have a deleted node as a source is ReplacedValues. 538/// Other maps can have deleted nodes as targets, but since their looked-up 539/// values are always immediately remapped using RemapValue, resulting in a 540/// not-deleted node, this is harmless as long as ReplacedValues/RemapValue 541/// always performs correct mappings. In order to keep the mapping correct, 542/// ExpungeNode should be called on any new nodes *before* adding them as 543/// either source or target to ReplacedValues (which typically means calling 544/// Expunge when a new node is first seen, since it may no longer be marked 545/// NewNode by the time it is added to ReplacedValues). 546void DAGTypeLegalizer::ExpungeNode(SDNode *N) { 547 if (N->getNodeId() != NewNode) 548 return; 549 550 // If N is not remapped by ReplacedValues then there is nothing to do. 551 unsigned i, e; 552 for (i = 0, e = N->getNumValues(); i != e; ++i) 553 if (ReplacedValues.find(SDValue(N, i)) != ReplacedValues.end()) 554 break; 555 556 if (i == e) 557 return; 558 559 // Remove N from all maps - this is expensive but rare. 560 561 for (DenseMap<SDValue, SDValue>::iterator I = PromotedIntegers.begin(), 562 E = PromotedIntegers.end(); I != E; ++I) { 563 assert(I->first.getNode() != N); 564 RemapValue(I->second); 565 } 566 567 for (DenseMap<SDValue, SDValue>::iterator I = SoftenedFloats.begin(), 568 E = SoftenedFloats.end(); I != E; ++I) { 569 assert(I->first.getNode() != N); 570 RemapValue(I->second); 571 } 572 573 for (DenseMap<SDValue, SDValue>::iterator I = ScalarizedVectors.begin(), 574 E = ScalarizedVectors.end(); I != E; ++I) { 575 assert(I->first.getNode() != N); 576 RemapValue(I->second); 577 } 578 579 for (DenseMap<SDValue, SDValue>::iterator I = WidenedVectors.begin(), 580 E = WidenedVectors.end(); I != E; ++I) { 581 assert(I->first.getNode() != N); 582 RemapValue(I->second); 583 } 584 585 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 586 I = ExpandedIntegers.begin(), E = ExpandedIntegers.end(); I != E; ++I){ 587 assert(I->first.getNode() != N); 588 RemapValue(I->second.first); 589 RemapValue(I->second.second); 590 } 591 592 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 593 I = ExpandedFloats.begin(), E = ExpandedFloats.end(); I != E; ++I) { 594 assert(I->first.getNode() != N); 595 RemapValue(I->second.first); 596 RemapValue(I->second.second); 597 } 598 599 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 600 I = SplitVectors.begin(), E = SplitVectors.end(); I != E; ++I) { 601 assert(I->first.getNode() != N); 602 RemapValue(I->second.first); 603 RemapValue(I->second.second); 604 } 605 606 for (DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.begin(), 607 E = ReplacedValues.end(); I != E; ++I) 608 RemapValue(I->second); 609 610 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 611 ReplacedValues.erase(SDValue(N, i)); 612} 613 614/// RemapValue - If the specified value was already legalized to another value, 615/// replace it by that value. 616void DAGTypeLegalizer::RemapValue(SDValue &N) { 617 DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(N); 618 if (I != ReplacedValues.end()) { 619 // Use path compression to speed up future lookups if values get multiply 620 // replaced with other values. 621 RemapValue(I->second); 622 N = I->second; 623 assert(N.getNode()->getNodeId() != NewNode && "Mapped to new node!"); 624 } 625} 626 627namespace { 628 /// NodeUpdateListener - This class is a DAGUpdateListener that listens for 629 /// updates to nodes and recomputes their ready state. 630 class NodeUpdateListener : public SelectionDAG::DAGUpdateListener { 631 DAGTypeLegalizer &DTL; 632 SmallSetVector<SDNode*, 16> &NodesToAnalyze; 633 public: 634 explicit NodeUpdateListener(DAGTypeLegalizer &dtl, 635 SmallSetVector<SDNode*, 16> &nta) 636 : DTL(dtl), NodesToAnalyze(nta) {} 637 638 virtual void NodeDeleted(SDNode *N, SDNode *E) { 639 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 640 N->getNodeId() != DAGTypeLegalizer::Processed && 641 "Invalid node ID for RAUW deletion!"); 642 // It is possible, though rare, for the deleted node N to occur as a 643 // target in a map, so note the replacement N -> E in ReplacedValues. 644 assert(E && "Node not replaced?"); 645 DTL.NoteDeletion(N, E); 646 647 // In theory the deleted node could also have been scheduled for analysis. 648 // So remove it from the set of nodes which will be analyzed. 649 NodesToAnalyze.remove(N); 650 651 // In general nothing needs to be done for E, since it didn't change but 652 // only gained new uses. However N -> E was just added to ReplacedValues, 653 // and the result of a ReplacedValues mapping is not allowed to be marked 654 // NewNode. So if E is marked NewNode, then it needs to be analyzed. 655 if (E->getNodeId() == DAGTypeLegalizer::NewNode) 656 NodesToAnalyze.insert(E); 657 } 658 659 virtual void NodeUpdated(SDNode *N) { 660 // Node updates can mean pretty much anything. It is possible that an 661 // operand was set to something already processed (f.e.) in which case 662 // this node could become ready. Recompute its flags. 663 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 664 N->getNodeId() != DAGTypeLegalizer::Processed && 665 "Invalid node ID for RAUW deletion!"); 666 N->setNodeId(DAGTypeLegalizer::NewNode); 667 NodesToAnalyze.insert(N); 668 } 669 }; 670} 671 672 673/// ReplaceValueWith - The specified value was legalized to the specified other 674/// value. Update the DAG and NodeIds replacing any uses of From to use To 675/// instead. 676void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) { 677 assert(From.getNode() != To.getNode() && "Potential legalization loop!"); 678 679 // If expansion produced new nodes, make sure they are properly marked. 680 ExpungeNode(From.getNode()); 681 AnalyzeNewValue(To); // Expunges To. 682 683 // Anything that used the old node should now use the new one. Note that this 684 // can potentially cause recursive merging. 685 SmallSetVector<SDNode*, 16> NodesToAnalyze; 686 NodeUpdateListener NUL(*this, NodesToAnalyze); 687 DAG.ReplaceAllUsesOfValueWith(From, To, &NUL); 688 689 // The old node may still be present in a map like ExpandedIntegers or 690 // PromotedIntegers. Inform maps about the replacement. 691 ReplacedValues[From] = To; 692 693 // Process the list of nodes that need to be reanalyzed. 694 while (!NodesToAnalyze.empty()) { 695 SDNode *N = NodesToAnalyze.back(); 696 NodesToAnalyze.pop_back(); 697 if (N->getNodeId() != DAGTypeLegalizer::NewNode) 698 // The node was analyzed while reanalyzing an earlier node - it is safe to 699 // skip. Note that this is not a morphing node - otherwise it would still 700 // be marked NewNode. 701 continue; 702 703 // Analyze the node's operands and recalculate the node ID. 704 SDNode *M = AnalyzeNewNode(N); 705 if (M != N) { 706 // The node morphed into a different node. Make everyone use the new node 707 // instead. 708 assert(M->getNodeId() != NewNode && "Analysis resulted in NewNode!"); 709 assert(N->getNumValues() == M->getNumValues() && 710 "Node morphing changed the number of results!"); 711 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) { 712 SDValue OldVal(N, i); 713 SDValue NewVal(M, i); 714 if (M->getNodeId() == Processed) 715 RemapValue(NewVal); 716 DAG.ReplaceAllUsesOfValueWith(OldVal, NewVal, &NUL); 717 } 718 // The original node continues to exist in the DAG, marked NewNode. 719 } 720 } 721} 722 723void DAGTypeLegalizer::SetPromotedInteger(SDValue Op, SDValue Result) { 724 assert(Result.getValueType() == 725 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 726 "Invalid type for promoted integer"); 727 AnalyzeNewValue(Result); 728 729 SDValue &OpEntry = PromotedIntegers[Op]; 730 assert(OpEntry.getNode() == 0 && "Node is already promoted!"); 731 OpEntry = Result; 732} 733 734void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) { 735 assert(Result.getValueType() == 736 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 737 "Invalid type for softened float"); 738 AnalyzeNewValue(Result); 739 740 SDValue &OpEntry = SoftenedFloats[Op]; 741 assert(OpEntry.getNode() == 0 && "Node is already converted to integer!"); 742 OpEntry = Result; 743} 744 745void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) { 746 assert(Result.getValueType() == Op.getValueType().getVectorElementType() && 747 "Invalid type for scalarized vector"); 748 AnalyzeNewValue(Result); 749 750 SDValue &OpEntry = ScalarizedVectors[Op]; 751 assert(OpEntry.getNode() == 0 && "Node is already scalarized!"); 752 OpEntry = Result; 753} 754 755void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo, 756 SDValue &Hi) { 757 std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op]; 758 RemapValue(Entry.first); 759 RemapValue(Entry.second); 760 assert(Entry.first.getNode() && "Operand isn't expanded"); 761 Lo = Entry.first; 762 Hi = Entry.second; 763} 764 765void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo, 766 SDValue Hi) { 767 assert(Lo.getValueType() == 768 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 769 Hi.getValueType() == Lo.getValueType() && 770 "Invalid type for expanded integer"); 771 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 772 AnalyzeNewValue(Lo); 773 AnalyzeNewValue(Hi); 774 775 // Remember that this is the result of the node. 776 std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op]; 777 assert(Entry.first.getNode() == 0 && "Node already expanded"); 778 Entry.first = Lo; 779 Entry.second = Hi; 780} 781 782void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo, 783 SDValue &Hi) { 784 std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op]; 785 RemapValue(Entry.first); 786 RemapValue(Entry.second); 787 assert(Entry.first.getNode() && "Operand isn't expanded"); 788 Lo = Entry.first; 789 Hi = Entry.second; 790} 791 792void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo, 793 SDValue Hi) { 794 assert(Lo.getValueType() == 795 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 796 Hi.getValueType() == Lo.getValueType() && 797 "Invalid type for expanded float"); 798 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 799 AnalyzeNewValue(Lo); 800 AnalyzeNewValue(Hi); 801 802 // Remember that this is the result of the node. 803 std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op]; 804 assert(Entry.first.getNode() == 0 && "Node already expanded"); 805 Entry.first = Lo; 806 Entry.second = Hi; 807} 808 809void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo, 810 SDValue &Hi) { 811 std::pair<SDValue, SDValue> &Entry = SplitVectors[Op]; 812 RemapValue(Entry.first); 813 RemapValue(Entry.second); 814 assert(Entry.first.getNode() && "Operand isn't split"); 815 Lo = Entry.first; 816 Hi = Entry.second; 817} 818 819void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo, 820 SDValue Hi) { 821 assert(Lo.getValueType().getVectorElementType() == 822 Op.getValueType().getVectorElementType() && 823 2*Lo.getValueType().getVectorNumElements() == 824 Op.getValueType().getVectorNumElements() && 825 Hi.getValueType() == Lo.getValueType() && 826 "Invalid type for split vector"); 827 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 828 AnalyzeNewValue(Lo); 829 AnalyzeNewValue(Hi); 830 831 // Remember that this is the result of the node. 832 std::pair<SDValue, SDValue> &Entry = SplitVectors[Op]; 833 assert(Entry.first.getNode() == 0 && "Node already split"); 834 Entry.first = Lo; 835 Entry.second = Hi; 836} 837 838void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) { 839 assert(Result.getValueType() == 840 TLI.getTypeToTransformTo(*DAG.getContext(), Op.getValueType()) && 841 "Invalid type for widened vector"); 842 AnalyzeNewValue(Result); 843 844 SDValue &OpEntry = WidenedVectors[Op]; 845 assert(OpEntry.getNode() == 0 && "Node already widened!"); 846 OpEntry = Result; 847} 848 849 850//===----------------------------------------------------------------------===// 851// Utilities. 852//===----------------------------------------------------------------------===// 853 854/// BitConvertToInteger - Convert to an integer of the same size. 855SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) { 856 unsigned BitWidth = Op.getValueType().getSizeInBits(); 857 return DAG.getNode(ISD::BIT_CONVERT, Op.getDebugLoc(), 858 EVT::getIntegerVT(*DAG.getContext(), BitWidth), Op); 859} 860 861/// BitConvertVectorToIntegerVector - Convert to a vector of integers of the 862/// same size. 863SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) { 864 assert(Op.getValueType().isVector() && "Only applies to vectors!"); 865 unsigned EltWidth = Op.getValueType().getVectorElementType().getSizeInBits(); 866 EVT EltNVT = EVT::getIntegerVT(*DAG.getContext(), EltWidth); 867 unsigned NumElts = Op.getValueType().getVectorNumElements(); 868 return DAG.getNode(ISD::BIT_CONVERT, Op.getDebugLoc(), 869 EVT::getVectorVT(*DAG.getContext(), EltNVT, NumElts), Op); 870} 871 872SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op, 873 EVT DestVT) { 874 DebugLoc dl = Op.getDebugLoc(); 875 // Create the stack frame object. Make sure it is aligned for both 876 // the source and destination types. 877 SDValue StackPtr = DAG.CreateStackTemporary(Op.getValueType(), DestVT); 878 // Emit a store to the stack slot. 879 SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Op, StackPtr, NULL, 0, 880 false, false, 0); 881 // Result is a load from the stack slot. 882 return DAG.getLoad(DestVT, dl, Store, StackPtr, NULL, 0, false, false, 0); 883} 884 885/// CustomLowerNode - Replace the node's results with custom code provided 886/// by the target and return "true", or do nothing and return "false". 887/// The last parameter is FALSE if we are dealing with a node with legal 888/// result types and illegal operand. The second parameter denotes the type of 889/// illegal OperandNo in that case. 890/// The last parameter being TRUE means we are dealing with a 891/// node with illegal result types. The second parameter denotes the type of 892/// illegal ResNo in that case. 893bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) { 894 // See if the target wants to custom lower this node. 895 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom) 896 return false; 897 898 SmallVector<SDValue, 8> Results; 899 if (LegalizeResult) 900 TLI.ReplaceNodeResults(N, Results, DAG); 901 else 902 TLI.LowerOperationWrapper(N, Results, DAG); 903 904 if (Results.empty()) 905 // The target didn't want to custom lower it after all. 906 return false; 907 908 // Make everything that once used N's values now use those in Results instead. 909 assert(Results.size() == N->getNumValues() && 910 "Custom lowering returned the wrong number of results!"); 911 for (unsigned i = 0, e = Results.size(); i != e; ++i) 912 ReplaceValueWith(SDValue(N, i), Results[i]); 913 return true; 914} 915 916 917/// CustomWidenLowerNode - Widen the node's results with custom code provided 918/// by the target and return "true", or do nothing and return "false". 919bool DAGTypeLegalizer::CustomWidenLowerNode(SDNode *N, EVT VT) { 920 // See if the target wants to custom lower this node. 921 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom) 922 return false; 923 924 SmallVector<SDValue, 8> Results; 925 TLI.ReplaceNodeResults(N, Results, DAG); 926 927 if (Results.empty()) 928 // The target didn't want to custom widen lower its result after all. 929 return false; 930 931 // Update the widening map. 932 assert(Results.size() == N->getNumValues() && 933 "Custom lowering returned the wrong number of results!"); 934 for (unsigned i = 0, e = Results.size(); i != e; ++i) 935 SetWidenedVector(SDValue(N, i), Results[i]); 936 return true; 937} 938 939/// GetSplitDestVTs - Compute the VTs needed for the low/hi parts of a type 940/// which is split into two not necessarily identical pieces. 941void DAGTypeLegalizer::GetSplitDestVTs(EVT InVT, EVT &LoVT, EVT &HiVT) { 942 // Currently all types are split in half. 943 if (!InVT.isVector()) { 944 LoVT = HiVT = TLI.getTypeToTransformTo(*DAG.getContext(), InVT); 945 } else { 946 unsigned NumElements = InVT.getVectorNumElements(); 947 assert(!(NumElements & 1) && "Splitting vector, but not in half!"); 948 LoVT = HiVT = EVT::getVectorVT(*DAG.getContext(), 949 InVT.getVectorElementType(), NumElements/2); 950 } 951} 952 953/// GetPairElements - Use ISD::EXTRACT_ELEMENT nodes to extract the low and 954/// high parts of the given value. 955void DAGTypeLegalizer::GetPairElements(SDValue Pair, 956 SDValue &Lo, SDValue &Hi) { 957 DebugLoc dl = Pair.getDebugLoc(); 958 EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), Pair.getValueType()); 959 Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair, 960 DAG.getIntPtrConstant(0)); 961 Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair, 962 DAG.getIntPtrConstant(1)); 963} 964 965SDValue DAGTypeLegalizer::GetVectorElementPointer(SDValue VecPtr, EVT EltVT, 966 SDValue Index) { 967 DebugLoc dl = Index.getDebugLoc(); 968 // Make sure the index type is big enough to compute in. 969 if (Index.getValueType().bitsGT(TLI.getPointerTy())) 970 Index = DAG.getNode(ISD::TRUNCATE, dl, TLI.getPointerTy(), Index); 971 else 972 Index = DAG.getNode(ISD::ZERO_EXTEND, dl, TLI.getPointerTy(), Index); 973 974 // Calculate the element offset and add it to the pointer. 975 unsigned EltSize = EltVT.getSizeInBits() / 8; // FIXME: should be ABI size. 976 977 Index = DAG.getNode(ISD::MUL, dl, Index.getValueType(), Index, 978 DAG.getConstant(EltSize, Index.getValueType())); 979 return DAG.getNode(ISD::ADD, dl, Index.getValueType(), Index, VecPtr); 980} 981 982/// JoinIntegers - Build an integer with low bits Lo and high bits Hi. 983SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) { 984 // Arbitrarily use dlHi for result DebugLoc 985 DebugLoc dlHi = Hi.getDebugLoc(); 986 DebugLoc dlLo = Lo.getDebugLoc(); 987 EVT LVT = Lo.getValueType(); 988 EVT HVT = Hi.getValueType(); 989 EVT NVT = EVT::getIntegerVT(*DAG.getContext(), 990 LVT.getSizeInBits() + HVT.getSizeInBits()); 991 992 Lo = DAG.getNode(ISD::ZERO_EXTEND, dlLo, NVT, Lo); 993 Hi = DAG.getNode(ISD::ANY_EXTEND, dlHi, NVT, Hi); 994 Hi = DAG.getNode(ISD::SHL, dlHi, NVT, Hi, 995 DAG.getConstant(LVT.getSizeInBits(), TLI.getPointerTy())); 996 return DAG.getNode(ISD::OR, dlHi, NVT, Lo, Hi); 997} 998 999/// LibCallify - Convert the node into a libcall with the same prototype. 1000SDValue DAGTypeLegalizer::LibCallify(RTLIB::Libcall LC, SDNode *N, 1001 bool isSigned) { 1002 unsigned NumOps = N->getNumOperands(); 1003 DebugLoc dl = N->getDebugLoc(); 1004 if (NumOps == 0) { 1005 return MakeLibCall(LC, N->getValueType(0), 0, 0, isSigned, dl); 1006 } else if (NumOps == 1) { 1007 SDValue Op = N->getOperand(0); 1008 return MakeLibCall(LC, N->getValueType(0), &Op, 1, isSigned, dl); 1009 } else if (NumOps == 2) { 1010 SDValue Ops[2] = { N->getOperand(0), N->getOperand(1) }; 1011 return MakeLibCall(LC, N->getValueType(0), Ops, 2, isSigned, dl); 1012 } 1013 SmallVector<SDValue, 8> Ops(NumOps); 1014 for (unsigned i = 0; i < NumOps; ++i) 1015 Ops[i] = N->getOperand(i); 1016 1017 return MakeLibCall(LC, N->getValueType(0), &Ops[0], NumOps, isSigned, dl); 1018} 1019 1020/// MakeLibCall - Generate a libcall taking the given operands as arguments and 1021/// returning a result of type RetVT. 1022SDValue DAGTypeLegalizer::MakeLibCall(RTLIB::Libcall LC, EVT RetVT, 1023 const SDValue *Ops, unsigned NumOps, 1024 bool isSigned, DebugLoc dl) { 1025 TargetLowering::ArgListTy Args; 1026 Args.reserve(NumOps); 1027 1028 TargetLowering::ArgListEntry Entry; 1029 for (unsigned i = 0; i != NumOps; ++i) { 1030 Entry.Node = Ops[i]; 1031 Entry.Ty = Entry.Node.getValueType().getTypeForEVT(*DAG.getContext()); 1032 Entry.isSExt = isSigned; 1033 Entry.isZExt = !isSigned; 1034 Args.push_back(Entry); 1035 } 1036 SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC), 1037 TLI.getPointerTy()); 1038 1039 const Type *RetTy = RetVT.getTypeForEVT(*DAG.getContext()); 1040 std::pair<SDValue,SDValue> CallInfo = 1041 TLI.LowerCallTo(DAG.getEntryNode(), RetTy, isSigned, !isSigned, false, 1042 false, 0, TLI.getLibcallCallingConv(LC), false, 1043 /*isReturnValueUsed=*/true, 1044 Callee, Args, DAG, dl); 1045 return CallInfo.first; 1046} 1047 1048/// PromoteTargetBoolean - Promote the given target boolean to a target boolean 1049/// of the given type. A target boolean is an integer value, not necessarily of 1050/// type i1, the bits of which conform to getBooleanContents. 1051SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT VT) { 1052 DebugLoc dl = Bool.getDebugLoc(); 1053 ISD::NodeType ExtendCode; 1054 switch (TLI.getBooleanContents()) { 1055 default: 1056 assert(false && "Unknown BooleanContent!"); 1057 case TargetLowering::UndefinedBooleanContent: 1058 // Extend to VT by adding rubbish bits. 1059 ExtendCode = ISD::ANY_EXTEND; 1060 break; 1061 case TargetLowering::ZeroOrOneBooleanContent: 1062 // Extend to VT by adding zero bits. 1063 ExtendCode = ISD::ZERO_EXTEND; 1064 break; 1065 case TargetLowering::ZeroOrNegativeOneBooleanContent: { 1066 // Extend to VT by copying the sign bit. 1067 ExtendCode = ISD::SIGN_EXTEND; 1068 break; 1069 } 1070 } 1071 return DAG.getNode(ExtendCode, dl, VT, Bool); 1072} 1073 1074/// SplitInteger - Return the lower LoVT bits of Op in Lo and the upper HiVT 1075/// bits in Hi. 1076void DAGTypeLegalizer::SplitInteger(SDValue Op, 1077 EVT LoVT, EVT HiVT, 1078 SDValue &Lo, SDValue &Hi) { 1079 DebugLoc dl = Op.getDebugLoc(); 1080 assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() == 1081 Op.getValueType().getSizeInBits() && "Invalid integer splitting!"); 1082 Lo = DAG.getNode(ISD::TRUNCATE, dl, LoVT, Op); 1083 Hi = DAG.getNode(ISD::SRL, dl, Op.getValueType(), Op, 1084 DAG.getConstant(LoVT.getSizeInBits(), TLI.getPointerTy())); 1085 Hi = DAG.getNode(ISD::TRUNCATE, dl, HiVT, Hi); 1086} 1087 1088/// SplitInteger - Return the lower and upper halves of Op's bits in a value 1089/// type half the size of Op's. 1090void DAGTypeLegalizer::SplitInteger(SDValue Op, 1091 SDValue &Lo, SDValue &Hi) { 1092 EVT HalfVT = EVT::getIntegerVT(*DAG.getContext(), 1093 Op.getValueType().getSizeInBits()/2); 1094 SplitInteger(Op, HalfVT, HalfVT, Lo, Hi); 1095} 1096 1097 1098//===----------------------------------------------------------------------===// 1099// Entry Point 1100//===----------------------------------------------------------------------===// 1101 1102/// LegalizeTypes - This transforms the SelectionDAG into a SelectionDAG that 1103/// only uses types natively supported by the target. Returns "true" if it made 1104/// any changes. 1105/// 1106/// Note that this is an involved process that may invalidate pointers into 1107/// the graph. 1108bool SelectionDAG::LegalizeTypes() { 1109 return DAGTypeLegalizer(*this).run(); 1110} 1111