LegalizeTypes.cpp revision ac9de036dc0e4065ee2c03419f11515a34ce505e
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/ADT/SetVector.h" 19#include "llvm/Support/CommandLine.h" 20#include "llvm/Support/ErrorHandling.h" 21#include "llvm/Target/TargetData.h" 22using namespace llvm; 23 24static cl::opt<bool> 25EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden); 26 27/// PerformExpensiveChecks - Do extensive, expensive, sanity checking. 28void DAGTypeLegalizer::PerformExpensiveChecks() { 29 // If a node is not processed, then none of its values should be mapped by any 30 // of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues. 31 32 // If a node is processed, then each value with an illegal type must be mapped 33 // by exactly one of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues. 34 // Values with a legal type may be mapped by ReplacedValues, but not by any of 35 // the other maps. 36 37 // Note that these invariants may not hold momentarily when processing a node: 38 // the node being processed may be put in a map before being marked Processed. 39 40 // Note that it is possible to have nodes marked NewNode in the DAG. This can 41 // occur in two ways. Firstly, a node may be created during legalization but 42 // never passed to the legalization core. This is usually due to the implicit 43 // folding that occurs when using the DAG.getNode operators. Secondly, a new 44 // node may be passed to the legalization core, but when analyzed may morph 45 // into a different node, leaving the original node as a NewNode in the DAG. 46 // A node may morph if one of its operands changes during analysis. Whether 47 // it actually morphs or not depends on whether, after updating its operands, 48 // it is equivalent to an existing node: if so, it morphs into that existing 49 // node (CSE). An operand can change during analysis if the operand is a new 50 // node that morphs, or it is a processed value that was mapped to some other 51 // value (as recorded in ReplacedValues) in which case the operand is turned 52 // into that other value. If a node morphs then the node it morphed into will 53 // be used instead of it for legalization, however the original node continues 54 // to live on in the DAG. 55 // The conclusion is that though there may be nodes marked NewNode in the DAG, 56 // all uses of such nodes are also marked NewNode: the result is a fungus of 57 // NewNodes growing on top of the useful nodes, and perhaps using them, but 58 // not used by them. 59 60 // If a value is mapped by ReplacedValues, then it must have no uses, except 61 // by nodes marked NewNode (see above). 62 63 // The final node obtained by mapping by ReplacedValues is not marked NewNode. 64 // Note that ReplacedValues should be applied iteratively. 65 66 // Note that the ReplacedValues map may also map deleted nodes. By iterating 67 // over the DAG we only consider non-deleted nodes. 68 SmallVector<SDNode*, 16> NewNodes; 69 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 70 E = DAG.allnodes_end(); I != E; ++I) { 71 // Remember nodes marked NewNode - they are subject to extra checking below. 72 if (I->getNodeId() == NewNode) 73 NewNodes.push_back(I); 74 75 for (unsigned i = 0, e = I->getNumValues(); i != e; ++i) { 76 SDValue Res(I, i); 77 bool Failed = false; 78 79 unsigned Mapped = 0; 80 if (ReplacedValues.find(Res) != ReplacedValues.end()) { 81 Mapped |= 1; 82 // Check that remapped values are only used by nodes marked NewNode. 83 for (SDNode::use_iterator UI = I->use_begin(), UE = I->use_end(); 84 UI != UE; ++UI) 85 if (UI.getUse().getResNo() == i) 86 assert(UI->getNodeId() == NewNode && 87 "Remapped value has non-trivial use!"); 88 89 // Check that the final result of applying ReplacedValues is not 90 // marked NewNode. 91 SDValue NewVal = ReplacedValues[Res]; 92 DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(NewVal); 93 while (I != ReplacedValues.end()) { 94 NewVal = I->second; 95 I = ReplacedValues.find(NewVal); 96 } 97 assert(NewVal.getNode()->getNodeId() != NewNode && 98 "ReplacedValues maps to a new node!"); 99 } 100 if (PromotedIntegers.find(Res) != PromotedIntegers.end()) 101 Mapped |= 2; 102 if (SoftenedFloats.find(Res) != SoftenedFloats.end()) 103 Mapped |= 4; 104 if (ScalarizedVectors.find(Res) != ScalarizedVectors.end()) 105 Mapped |= 8; 106 if (ExpandedIntegers.find(Res) != ExpandedIntegers.end()) 107 Mapped |= 16; 108 if (ExpandedFloats.find(Res) != ExpandedFloats.end()) 109 Mapped |= 32; 110 if (SplitVectors.find(Res) != SplitVectors.end()) 111 Mapped |= 64; 112 if (WidenedVectors.find(Res) != WidenedVectors.end()) 113 Mapped |= 128; 114 115 if (I->getNodeId() != Processed) { 116 if (Mapped != 0) { 117 cerr << "Unprocessed value in a map!"; 118 Failed = true; 119 } 120 } else if (isTypeLegal(Res.getValueType()) || IgnoreNodeResults(I)) { 121 if (Mapped > 1) { 122 cerr << "Value with legal type was transformed!"; 123 Failed = true; 124 } 125 } else { 126 if (Mapped == 0) { 127 cerr << "Processed value not in any map!"; 128 Failed = true; 129 } else if (Mapped & (Mapped - 1)) { 130 cerr << "Value in multiple maps!"; 131 Failed = true; 132 } 133 } 134 135 if (Failed) { 136 if (Mapped & 1) 137 cerr << " ReplacedValues"; 138 if (Mapped & 2) 139 cerr << " PromotedIntegers"; 140 if (Mapped & 4) 141 cerr << " SoftenedFloats"; 142 if (Mapped & 8) 143 cerr << " ScalarizedVectors"; 144 if (Mapped & 16) 145 cerr << " ExpandedIntegers"; 146 if (Mapped & 32) 147 cerr << " ExpandedFloats"; 148 if (Mapped & 64) 149 cerr << " SplitVectors"; 150 if (Mapped & 128) 151 cerr << " WidenedVectors"; 152 cerr << "\n"; 153 llvm_unreachable(0); 154 } 155 } 156 } 157 158 // Checked that NewNodes are only used by other NewNodes. 159 for (unsigned i = 0, e = NewNodes.size(); i != e; ++i) { 160 SDNode *N = NewNodes[i]; 161 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 162 UI != UE; ++UI) 163 assert(UI->getNodeId() == NewNode && "NewNode used by non-NewNode!"); 164 } 165} 166 167/// run - This is the main entry point for the type legalizer. This does a 168/// top-down traversal of the dag, legalizing types as it goes. Returns "true" 169/// if it made any changes. 170bool DAGTypeLegalizer::run() { 171 bool Changed = false; 172 173 // Create a dummy node (which is not added to allnodes), that adds a reference 174 // to the root node, preventing it from being deleted, and tracking any 175 // changes of the root. 176 HandleSDNode Dummy(DAG.getRoot()); 177 Dummy.setNodeId(Unanalyzed); 178 179 // The root of the dag may dangle to deleted nodes until the type legalizer is 180 // done. Set it to null to avoid confusion. 181 DAG.setRoot(SDValue()); 182 183 // Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess' 184 // (and remembering them) if they are leaves and assigning 'Unanalyzed' if 185 // non-leaves. 186 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 187 E = DAG.allnodes_end(); I != E; ++I) { 188 if (I->getNumOperands() == 0) { 189 I->setNodeId(ReadyToProcess); 190 Worklist.push_back(I); 191 } else { 192 I->setNodeId(Unanalyzed); 193 } 194 } 195 196 // Now that we have a set of nodes to process, handle them all. 197 while (!Worklist.empty()) { 198#ifndef XDEBUG 199 if (EnableExpensiveChecks) 200#endif 201 PerformExpensiveChecks(); 202 203 SDNode *N = Worklist.back(); 204 Worklist.pop_back(); 205 assert(N->getNodeId() == ReadyToProcess && 206 "Node should be ready if on worklist!"); 207 208 if (IgnoreNodeResults(N)) 209 goto ScanOperands; 210 211 // Scan the values produced by the node, checking to see if any result 212 // types are illegal. 213 for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) { 214 EVT ResultVT = N->getValueType(i); 215 switch (getTypeAction(ResultVT)) { 216 default: 217 assert(false && "Unknown action!"); 218 case Legal: 219 break; 220 // The following calls must take care of *all* of the node's results, 221 // not just the illegal result they were passed (this includes results 222 // with a legal type). Results can be remapped using ReplaceValueWith, 223 // or their promoted/expanded/etc values registered in PromotedIntegers, 224 // ExpandedIntegers etc. 225 case PromoteInteger: 226 PromoteIntegerResult(N, i); 227 Changed = true; 228 goto NodeDone; 229 case ExpandInteger: 230 ExpandIntegerResult(N, i); 231 Changed = true; 232 goto NodeDone; 233 case SoftenFloat: 234 SoftenFloatResult(N, i); 235 Changed = true; 236 goto NodeDone; 237 case ExpandFloat: 238 ExpandFloatResult(N, i); 239 Changed = true; 240 goto NodeDone; 241 case ScalarizeVector: 242 ScalarizeVectorResult(N, i); 243 Changed = true; 244 goto NodeDone; 245 case SplitVector: 246 SplitVectorResult(N, i); 247 Changed = true; 248 goto NodeDone; 249 case WidenVector: 250 WidenVectorResult(N, i); 251 Changed = true; 252 goto NodeDone; 253 } 254 } 255 256ScanOperands: 257 // Scan the operand list for the node, handling any nodes with operands that 258 // are illegal. 259 { 260 unsigned NumOperands = N->getNumOperands(); 261 bool NeedsReanalyzing = false; 262 unsigned i; 263 for (i = 0; i != NumOperands; ++i) { 264 if (IgnoreNodeResults(N->getOperand(i).getNode())) 265 continue; 266 267 EVT OpVT = N->getOperand(i).getValueType(); 268 switch (getTypeAction(OpVT)) { 269 default: 270 assert(false && "Unknown action!"); 271 case Legal: 272 continue; 273 // The following calls must either replace all of the node's results 274 // using ReplaceValueWith, and return "false"; or update the node's 275 // operands in place, and return "true". 276 case PromoteInteger: 277 NeedsReanalyzing = PromoteIntegerOperand(N, i); 278 Changed = true; 279 break; 280 case ExpandInteger: 281 NeedsReanalyzing = ExpandIntegerOperand(N, i); 282 Changed = true; 283 break; 284 case SoftenFloat: 285 NeedsReanalyzing = SoftenFloatOperand(N, i); 286 Changed = true; 287 break; 288 case ExpandFloat: 289 NeedsReanalyzing = ExpandFloatOperand(N, i); 290 Changed = true; 291 break; 292 case ScalarizeVector: 293 NeedsReanalyzing = ScalarizeVectorOperand(N, i); 294 Changed = true; 295 break; 296 case SplitVector: 297 NeedsReanalyzing = SplitVectorOperand(N, i); 298 Changed = true; 299 break; 300 case WidenVector: 301 NeedsReanalyzing = WidenVectorOperand(N, i); 302 Changed = true; 303 break; 304 } 305 break; 306 } 307 308 // The sub-method updated N in place. Check to see if any operands are new, 309 // and if so, mark them. If the node needs revisiting, don't add all users 310 // to the worklist etc. 311 if (NeedsReanalyzing) { 312 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 313 N->setNodeId(NewNode); 314 // Recompute the NodeId and correct processed operands, adding the node to 315 // the worklist if ready. 316 SDNode *M = AnalyzeNewNode(N); 317 if (M == N) 318 // The node didn't morph - nothing special to do, it will be revisited. 319 continue; 320 321 // The node morphed - this is equivalent to legalizing by replacing every 322 // value of N with the corresponding value of M. So do that now. However 323 // there is no need to remember the replacement - morphing will make sure 324 // it is never used non-trivially. 325 assert(N->getNumValues() == M->getNumValues() && 326 "Node morphing changed the number of results!"); 327 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 328 // Replacing the value takes care of remapping the new value. Do the 329 // replacement without recording it in ReplacedValues. This does not 330 // expunge From but that is fine - it is not really a new node. 331 ReplaceValueWithHelper(SDValue(N, i), SDValue(M, i)); 332 assert(N->getNodeId() == NewNode && "Unexpected node state!"); 333 // The node continues to live on as part of the NewNode fungus that 334 // grows on top of the useful nodes. Nothing more needs to be done 335 // with it - move on to the next node. 336 continue; 337 } 338 339 if (i == NumOperands) { 340 DEBUG(cerr << "Legally typed node: "; N->dump(&DAG); cerr << "\n"); 341 } 342 } 343NodeDone: 344 345 // If we reach here, the node was processed, potentially creating new nodes. 346 // Mark it as processed and add its users to the worklist as appropriate. 347 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 348 N->setNodeId(Processed); 349 350 for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end(); 351 UI != E; ++UI) { 352 SDNode *User = *UI; 353 int NodeId = User->getNodeId(); 354 355 // This node has two options: it can either be a new node or its Node ID 356 // may be a count of the number of operands it has that are not ready. 357 if (NodeId > 0) { 358 User->setNodeId(NodeId-1); 359 360 // If this was the last use it was waiting on, add it to the ready list. 361 if (NodeId-1 == ReadyToProcess) 362 Worklist.push_back(User); 363 continue; 364 } 365 366 // If this is an unreachable new node, then ignore it. If it ever becomes 367 // reachable by being used by a newly created node then it will be handled 368 // by AnalyzeNewNode. 369 if (NodeId == NewNode) 370 continue; 371 372 // Otherwise, this node is new: this is the first operand of it that 373 // became ready. Its new NodeId is the number of operands it has minus 1 374 // (as this node is now processed). 375 assert(NodeId == Unanalyzed && "Unknown node ID!"); 376 User->setNodeId(User->getNumOperands() - 1); 377 378 // If the node only has a single operand, it is now ready. 379 if (User->getNumOperands() == 1) 380 Worklist.push_back(User); 381 } 382 } 383 384#ifndef XDEBUG 385 if (EnableExpensiveChecks) 386#endif 387 PerformExpensiveChecks(); 388 389 // If the root changed (e.g. it was a dead load) update the root. 390 DAG.setRoot(Dummy.getValue()); 391 392 // Remove dead nodes. This is important to do for cleanliness but also before 393 // the checking loop below. Implicit folding by the DAG.getNode operators and 394 // node morphing can cause unreachable nodes to be around with their flags set 395 // to new. 396 DAG.RemoveDeadNodes(); 397 398 // In a debug build, scan all the nodes to make sure we found them all. This 399 // ensures that there are no cycles and that everything got processed. 400#ifndef NDEBUG 401 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 402 E = DAG.allnodes_end(); I != E; ++I) { 403 bool Failed = false; 404 405 // Check that all result types are legal. 406 if (!IgnoreNodeResults(I)) 407 for (unsigned i = 0, NumVals = I->getNumValues(); i < NumVals; ++i) 408 if (!isTypeLegal(I->getValueType(i))) { 409 cerr << "Result type " << i << " illegal!\n"; 410 Failed = true; 411 } 412 413 // Check that all operand types are legal. 414 for (unsigned i = 0, NumOps = I->getNumOperands(); i < NumOps; ++i) 415 if (!IgnoreNodeResults(I->getOperand(i).getNode()) && 416 !isTypeLegal(I->getOperand(i).getValueType())) { 417 cerr << "Operand type " << i << " illegal!\n"; 418 Failed = true; 419 } 420 421 if (I->getNodeId() != Processed) { 422 if (I->getNodeId() == NewNode) 423 cerr << "New node not analyzed?\n"; 424 else if (I->getNodeId() == Unanalyzed) 425 cerr << "Unanalyzed node not noticed?\n"; 426 else if (I->getNodeId() > 0) 427 cerr << "Operand not processed?\n"; 428 else if (I->getNodeId() == ReadyToProcess) 429 cerr << "Not added to worklist?\n"; 430 Failed = true; 431 } 432 433 if (Failed) { 434 I->dump(&DAG); cerr << "\n"; 435 llvm_unreachable(0); 436 } 437 } 438#endif 439 440 return Changed; 441} 442 443/// AnalyzeNewNode - The specified node is the root of a subtree of potentially 444/// new nodes. Correct any processed operands (this may change the node) and 445/// calculate the NodeId. If the node itself changes to a processed node, it 446/// is not remapped - the caller needs to take care of this. 447/// Returns the potentially changed node. 448SDNode *DAGTypeLegalizer::AnalyzeNewNode(SDNode *N) { 449 // If this was an existing node that is already done, we're done. 450 if (N->getNodeId() != NewNode && N->getNodeId() != Unanalyzed) 451 return N; 452 453 // Remove any stale map entries. 454 ExpungeNode(N); 455 456 // Okay, we know that this node is new. Recursively walk all of its operands 457 // to see if they are new also. The depth of this walk is bounded by the size 458 // of the new tree that was constructed (usually 2-3 nodes), so we don't worry 459 // about revisiting of nodes. 460 // 461 // As we walk the operands, keep track of the number of nodes that are 462 // processed. If non-zero, this will become the new nodeid of this node. 463 // Operands may morph when they are analyzed. If so, the node will be 464 // updated after all operands have been analyzed. Since this is rare, 465 // the code tries to minimize overhead in the non-morphing case. 466 467 SmallVector<SDValue, 8> NewOps; 468 unsigned NumProcessed = 0; 469 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) { 470 SDValue OrigOp = N->getOperand(i); 471 SDValue Op = OrigOp; 472 473 AnalyzeNewValue(Op); // Op may morph. 474 475 if (Op.getNode()->getNodeId() == Processed) 476 ++NumProcessed; 477 478 if (!NewOps.empty()) { 479 // Some previous operand changed. Add this one to the list. 480 NewOps.push_back(Op); 481 } else if (Op != OrigOp) { 482 // This is the first operand to change - add all operands so far. 483 NewOps.insert(NewOps.end(), N->op_begin(), N->op_begin() + i); 484 NewOps.push_back(Op); 485 } 486 } 487 488 // Some operands changed - update the node. 489 if (!NewOps.empty()) { 490 SDNode *M = DAG.UpdateNodeOperands(SDValue(N, 0), &NewOps[0], 491 NewOps.size()).getNode(); 492 if (M != N) { 493 // The node morphed into a different node. Normally for this to happen 494 // the original node would have to be marked NewNode. However this can 495 // in theory momentarily not be the case while ReplaceValueWith is doing 496 // its stuff. Mark the original node NewNode to help sanity checking. 497 N->setNodeId(NewNode); 498 if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed) 499 // It morphed into a previously analyzed node - nothing more to do. 500 return M; 501 502 // It morphed into a different new node. Do the equivalent of passing 503 // it to AnalyzeNewNode: expunge it and calculate the NodeId. No need 504 // to remap the operands, since they are the same as the operands we 505 // remapped above. 506 N = M; 507 ExpungeNode(N); 508 } 509 } 510 511 // Calculate the NodeId. 512 N->setNodeId(N->getNumOperands() - NumProcessed); 513 if (N->getNodeId() == ReadyToProcess) 514 Worklist.push_back(N); 515 516 return N; 517} 518 519/// AnalyzeNewValue - Call AnalyzeNewNode, updating the node in Val if needed. 520/// If the node changes to a processed node, then remap it. 521void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) { 522 Val.setNode(AnalyzeNewNode(Val.getNode())); 523 if (Val.getNode()->getNodeId() == Processed) 524 // We were passed a processed node, or it morphed into one - remap it. 525 RemapValue(Val); 526} 527 528/// ExpungeNode - If N has a bogus mapping in ReplacedValues, eliminate it. 529/// This can occur when a node is deleted then reallocated as a new node - 530/// the mapping in ReplacedValues applies to the deleted node, not the new 531/// one. 532/// The only map that can have a deleted node as a source is ReplacedValues. 533/// Other maps can have deleted nodes as targets, but since their looked-up 534/// values are always immediately remapped using RemapValue, resulting in a 535/// not-deleted node, this is harmless as long as ReplacedValues/RemapValue 536/// always performs correct mappings. In order to keep the mapping correct, 537/// ExpungeNode should be called on any new nodes *before* adding them as 538/// either source or target to ReplacedValues (which typically means calling 539/// Expunge when a new node is first seen, since it may no longer be marked 540/// NewNode by the time it is added to ReplacedValues). 541void DAGTypeLegalizer::ExpungeNode(SDNode *N) { 542 if (N->getNodeId() != NewNode) 543 return; 544 545 // If N is not remapped by ReplacedValues then there is nothing to do. 546 unsigned i, e; 547 for (i = 0, e = N->getNumValues(); i != e; ++i) 548 if (ReplacedValues.find(SDValue(N, i)) != ReplacedValues.end()) 549 break; 550 551 if (i == e) 552 return; 553 554 // Remove N from all maps - this is expensive but rare. 555 556 for (DenseMap<SDValue, SDValue>::iterator I = PromotedIntegers.begin(), 557 E = PromotedIntegers.end(); I != E; ++I) { 558 assert(I->first.getNode() != N); 559 RemapValue(I->second); 560 } 561 562 for (DenseMap<SDValue, SDValue>::iterator I = SoftenedFloats.begin(), 563 E = SoftenedFloats.end(); I != E; ++I) { 564 assert(I->first.getNode() != N); 565 RemapValue(I->second); 566 } 567 568 for (DenseMap<SDValue, SDValue>::iterator I = ScalarizedVectors.begin(), 569 E = ScalarizedVectors.end(); I != E; ++I) { 570 assert(I->first.getNode() != N); 571 RemapValue(I->second); 572 } 573 574 for (DenseMap<SDValue, SDValue>::iterator I = WidenedVectors.begin(), 575 E = WidenedVectors.end(); I != E; ++I) { 576 assert(I->first.getNode() != N); 577 RemapValue(I->second); 578 } 579 580 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 581 I = ExpandedIntegers.begin(), E = ExpandedIntegers.end(); I != E; ++I){ 582 assert(I->first.getNode() != N); 583 RemapValue(I->second.first); 584 RemapValue(I->second.second); 585 } 586 587 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 588 I = ExpandedFloats.begin(), E = ExpandedFloats.end(); I != E; ++I) { 589 assert(I->first.getNode() != N); 590 RemapValue(I->second.first); 591 RemapValue(I->second.second); 592 } 593 594 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 595 I = SplitVectors.begin(), E = SplitVectors.end(); I != E; ++I) { 596 assert(I->first.getNode() != N); 597 RemapValue(I->second.first); 598 RemapValue(I->second.second); 599 } 600 601 for (DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.begin(), 602 E = ReplacedValues.end(); I != E; ++I) 603 RemapValue(I->second); 604 605 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 606 ReplacedValues.erase(SDValue(N, i)); 607} 608 609/// RemapValue - If the specified value was already legalized to another value, 610/// replace it by that value. 611void DAGTypeLegalizer::RemapValue(SDValue &N) { 612 DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(N); 613 if (I != ReplacedValues.end()) { 614 // Use path compression to speed up future lookups if values get multiply 615 // replaced with other values. 616 RemapValue(I->second); 617 N = I->second; 618 assert(N.getNode()->getNodeId() != NewNode && "Mapped to new node!"); 619 } 620} 621 622namespace { 623 /// NodeUpdateListener - This class is a DAGUpdateListener that listens for 624 /// updates to nodes and recomputes their ready state. 625 class VISIBILITY_HIDDEN NodeUpdateListener : 626 public SelectionDAG::DAGUpdateListener { 627 DAGTypeLegalizer &DTL; 628 SmallSetVector<SDNode*, 16> &NodesToAnalyze; 629 public: 630 explicit NodeUpdateListener(DAGTypeLegalizer &dtl, 631 SmallSetVector<SDNode*, 16> &nta) 632 : DTL(dtl), NodesToAnalyze(nta) {} 633 634 virtual void NodeDeleted(SDNode *N, SDNode *E) { 635 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 636 N->getNodeId() != DAGTypeLegalizer::Processed && 637 "Invalid node ID for RAUW deletion!"); 638 // It is possible, though rare, for the deleted node N to occur as a 639 // target in a map, so note the replacement N -> E in ReplacedValues. 640 assert(E && "Node not replaced?"); 641 DTL.NoteDeletion(N, E); 642 643 // In theory the deleted node could also have been scheduled for analysis. 644 // So remove it from the set of nodes which will be analyzed. 645 NodesToAnalyze.remove(N); 646 647 // In general nothing needs to be done for E, since it didn't change but 648 // only gained new uses. However N -> E was just added to ReplacedValues, 649 // and the result of a ReplacedValues mapping is not allowed to be marked 650 // NewNode. So if E is marked NewNode, then it needs to be analyzed. 651 if (E->getNodeId() == DAGTypeLegalizer::NewNode) 652 NodesToAnalyze.insert(E); 653 } 654 655 virtual void NodeUpdated(SDNode *N) { 656 // Node updates can mean pretty much anything. It is possible that an 657 // operand was set to something already processed (f.e.) in which case 658 // this node could become ready. Recompute its flags. 659 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 660 N->getNodeId() != DAGTypeLegalizer::Processed && 661 "Invalid node ID for RAUW deletion!"); 662 N->setNodeId(DAGTypeLegalizer::NewNode); 663 NodesToAnalyze.insert(N); 664 } 665 }; 666} 667 668 669/// ReplaceValueWithHelper - Internal helper for ReplaceValueWith. Updates the 670/// DAG causing any uses of From to use To instead, but without expunging From 671/// or recording the replacement in ReplacedValues. Do not call directly unless 672/// you really know what you are doing! 673void DAGTypeLegalizer::ReplaceValueWithHelper(SDValue From, SDValue To) { 674 assert(From.getNode() != To.getNode() && "Potential legalization loop!"); 675 676 // If expansion produced new nodes, make sure they are properly marked. 677 AnalyzeNewValue(To); // Expunges To. 678 679 // Anything that used the old node should now use the new one. Note that this 680 // can potentially cause recursive merging. 681 SmallSetVector<SDNode*, 16> NodesToAnalyze; 682 NodeUpdateListener NUL(*this, NodesToAnalyze); 683 DAG.ReplaceAllUsesOfValueWith(From, To, &NUL); 684 685 // Process the list of nodes that need to be reanalyzed. 686 while (!NodesToAnalyze.empty()) { 687 SDNode *N = NodesToAnalyze.back(); 688 NodesToAnalyze.pop_back(); 689 if (N->getNodeId() != DAGTypeLegalizer::NewNode) 690 // The node was analyzed while reanalyzing an earlier node - it is safe to 691 // skip. Note that this is not a morphing node - otherwise it would still 692 // be marked NewNode. 693 continue; 694 695 // Analyze the node's operands and recalculate the node ID. 696 SDNode *M = AnalyzeNewNode(N); 697 if (M != N) { 698 // The node morphed into a different node. Make everyone use the new node 699 // instead. 700 assert(M->getNodeId() != NewNode && "Analysis resulted in NewNode!"); 701 assert(N->getNumValues() == M->getNumValues() && 702 "Node morphing changed the number of results!"); 703 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) { 704 SDValue OldVal(N, i); 705 SDValue NewVal(M, i); 706 if (M->getNodeId() == Processed) 707 RemapValue(NewVal); 708 DAG.ReplaceAllUsesOfValueWith(OldVal, NewVal, &NUL); 709 } 710 // The original node continues to exist in the DAG, marked NewNode. 711 } 712 } 713} 714 715/// ReplaceValueWith - The specified value was legalized to the specified other 716/// value. Update the DAG and NodeIds replacing any uses of From to use To 717/// instead. 718void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) { 719 assert(From.getNode()->getNodeId() == ReadyToProcess && 720 "Only the node being processed may be remapped!"); 721 722 // If expansion produced new nodes, make sure they are properly marked. 723 ExpungeNode(From.getNode()); 724 AnalyzeNewValue(To); // Expunges To. 725 726 // The old node may still be present in a map like ExpandedIntegers or 727 // PromotedIntegers. Inform maps about the replacement. 728 ReplacedValues[From] = To; 729 730 // Do the replacement. 731 ReplaceValueWithHelper(From, To); 732} 733 734void DAGTypeLegalizer::SetPromotedInteger(SDValue Op, SDValue Result) { 735 assert(Result.getValueType() == TLI.getTypeToTransformTo(Op.getValueType()) && 736 "Invalid type for promoted integer"); 737 AnalyzeNewValue(Result); 738 739 SDValue &OpEntry = PromotedIntegers[Op]; 740 assert(OpEntry.getNode() == 0 && "Node is already promoted!"); 741 OpEntry = Result; 742} 743 744void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) { 745 assert(Result.getValueType() == TLI.getTypeToTransformTo(Op.getValueType()) && 746 "Invalid type for softened float"); 747 AnalyzeNewValue(Result); 748 749 SDValue &OpEntry = SoftenedFloats[Op]; 750 assert(OpEntry.getNode() == 0 && "Node is already converted to integer!"); 751 OpEntry = Result; 752} 753 754void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) { 755 assert(Result.getValueType() == Op.getValueType().getVectorElementType() && 756 "Invalid type for scalarized vector"); 757 AnalyzeNewValue(Result); 758 759 SDValue &OpEntry = ScalarizedVectors[Op]; 760 assert(OpEntry.getNode() == 0 && "Node is already scalarized!"); 761 OpEntry = Result; 762} 763 764void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo, 765 SDValue &Hi) { 766 std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op]; 767 RemapValue(Entry.first); 768 RemapValue(Entry.second); 769 assert(Entry.first.getNode() && "Operand isn't expanded"); 770 Lo = Entry.first; 771 Hi = Entry.second; 772} 773 774void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo, 775 SDValue Hi) { 776 assert(Lo.getValueType() == TLI.getTypeToTransformTo(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 // Remember that this is the result of the node. 784 std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op]; 785 assert(Entry.first.getNode() == 0 && "Node already expanded"); 786 Entry.first = Lo; 787 Entry.second = Hi; 788} 789 790void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo, 791 SDValue &Hi) { 792 std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op]; 793 RemapValue(Entry.first); 794 RemapValue(Entry.second); 795 assert(Entry.first.getNode() && "Operand isn't expanded"); 796 Lo = Entry.first; 797 Hi = Entry.second; 798} 799 800void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo, 801 SDValue Hi) { 802 assert(Lo.getValueType() == TLI.getTypeToTransformTo(Op.getValueType()) && 803 Hi.getValueType() == Lo.getValueType() && 804 "Invalid type for expanded float"); 805 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 806 AnalyzeNewValue(Lo); 807 AnalyzeNewValue(Hi); 808 809 // Remember that this is the result of the node. 810 std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op]; 811 assert(Entry.first.getNode() == 0 && "Node already expanded"); 812 Entry.first = Lo; 813 Entry.second = Hi; 814} 815 816void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo, 817 SDValue &Hi) { 818 std::pair<SDValue, SDValue> &Entry = SplitVectors[Op]; 819 RemapValue(Entry.first); 820 RemapValue(Entry.second); 821 assert(Entry.first.getNode() && "Operand isn't split"); 822 Lo = Entry.first; 823 Hi = Entry.second; 824} 825 826void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo, 827 SDValue Hi) { 828 assert(Lo.getValueType().getVectorElementType() == 829 Op.getValueType().getVectorElementType() && 830 2*Lo.getValueType().getVectorNumElements() == 831 Op.getValueType().getVectorNumElements() && 832 Hi.getValueType() == Lo.getValueType() && 833 "Invalid type for split vector"); 834 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 835 AnalyzeNewValue(Lo); 836 AnalyzeNewValue(Hi); 837 838 // Remember that this is the result of the node. 839 std::pair<SDValue, SDValue> &Entry = SplitVectors[Op]; 840 assert(Entry.first.getNode() == 0 && "Node already split"); 841 Entry.first = Lo; 842 Entry.second = Hi; 843} 844 845void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) { 846 assert(Result.getValueType() == TLI.getTypeToTransformTo(Op.getValueType()) && 847 "Invalid type for widened vector"); 848 AnalyzeNewValue(Result); 849 850 SDValue &OpEntry = WidenedVectors[Op]; 851 assert(OpEntry.getNode() == 0 && "Node already widened!"); 852 OpEntry = Result; 853} 854 855 856//===----------------------------------------------------------------------===// 857// Utilities. 858//===----------------------------------------------------------------------===// 859 860/// BitConvertToInteger - Convert to an integer of the same size. 861SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) { 862 unsigned BitWidth = Op.getValueType().getSizeInBits(); 863 return DAG.getNode(ISD::BIT_CONVERT, Op.getDebugLoc(), 864 EVT::getIntegerVT(BitWidth), Op); 865} 866 867/// BitConvertVectorToIntegerVector - Convert to a vector of integers of the 868/// same size. 869SDValue DAGTypeLegalizer::BitConvertVectorToIntegerVector(SDValue Op) { 870 assert(Op.getValueType().isVector() && "Only applies to vectors!"); 871 unsigned EltWidth = Op.getValueType().getVectorElementType().getSizeInBits(); 872 EVT EltNVT = EVT::getIntegerVT(EltWidth); 873 unsigned NumElts = Op.getValueType().getVectorNumElements(); 874 return DAG.getNode(ISD::BIT_CONVERT, Op.getDebugLoc(), 875 EVT::getVectorVT(EltNVT, NumElts), Op); 876} 877 878SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op, 879 EVT DestVT) { 880 DebugLoc dl = Op.getDebugLoc(); 881 // Create the stack frame object. Make sure it is aligned for both 882 // the source and destination types. 883 SDValue StackPtr = DAG.CreateStackTemporary(Op.getValueType(), DestVT); 884 // Emit a store to the stack slot. 885 SDValue Store = DAG.getStore(DAG.getEntryNode(), dl, Op, StackPtr, NULL, 0); 886 // Result is a load from the stack slot. 887 return DAG.getLoad(DestVT, dl, Store, StackPtr, NULL, 0); 888} 889 890/// CustomLowerNode - Replace the node's results with custom code provided 891/// by the target and return "true", or do nothing and return "false". 892/// The last parameter is FALSE if we are dealing with a node with legal 893/// result types and illegal operand. The second parameter denotes the type of 894/// illegal OperandNo in that case. 895/// The last parameter being TRUE means we are dealing with a 896/// node with illegal result types. The second parameter denotes the type of 897/// illegal ResNo in that case. 898bool DAGTypeLegalizer::CustomLowerNode(SDNode *N, EVT VT, bool LegalizeResult) { 899 // See if the target wants to custom lower this node. 900 if (TLI.getOperationAction(N->getOpcode(), VT) != TargetLowering::Custom) 901 return false; 902 903 SmallVector<SDValue, 8> Results; 904 if (LegalizeResult) 905 TLI.ReplaceNodeResults(N, Results, DAG); 906 else 907 TLI.LowerOperationWrapper(N, Results, DAG); 908 909 if (Results.empty()) 910 // The target didn't want to custom lower it after all. 911 return false; 912 913 // Make everything that once used N's values now use those in Results instead. 914 assert(Results.size() == N->getNumValues() && 915 "Custom lowering returned the wrong number of results!"); 916 for (unsigned i = 0, e = Results.size(); i != e; ++i) 917 ReplaceValueWith(SDValue(N, i), Results[i]); 918 return true; 919} 920 921/// GetSplitDestVTs - Compute the VTs needed for the low/hi parts of a type 922/// which is split into two not necessarily identical pieces. 923void DAGTypeLegalizer::GetSplitDestVTs(EVT InVT, EVT &LoVT, EVT &HiVT) { 924 // Currently all types are split in half. 925 if (!InVT.isVector()) { 926 LoVT = HiVT = TLI.getTypeToTransformTo(InVT); 927 } else { 928 unsigned NumElements = InVT.getVectorNumElements(); 929 assert(!(NumElements & 1) && "Splitting vector, but not in half!"); 930 LoVT = HiVT = EVT::getVectorVT(InVT.getVectorElementType(), NumElements/2); 931 } 932} 933 934/// GetPairElements - Use ISD::EXTRACT_ELEMENT nodes to extract the low and 935/// high parts of the given value. 936void DAGTypeLegalizer::GetPairElements(SDValue Pair, 937 SDValue &Lo, SDValue &Hi) { 938 DebugLoc dl = Pair.getDebugLoc(); 939 EVT NVT = TLI.getTypeToTransformTo(Pair.getValueType()); 940 Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair, 941 DAG.getIntPtrConstant(0)); 942 Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, dl, NVT, Pair, 943 DAG.getIntPtrConstant(1)); 944} 945 946SDValue DAGTypeLegalizer::GetVectorElementPointer(SDValue VecPtr, EVT EltVT, 947 SDValue Index) { 948 DebugLoc dl = Index.getDebugLoc(); 949 // Make sure the index type is big enough to compute in. 950 if (Index.getValueType().bitsGT(TLI.getPointerTy())) 951 Index = DAG.getNode(ISD::TRUNCATE, dl, TLI.getPointerTy(), Index); 952 else 953 Index = DAG.getNode(ISD::ZERO_EXTEND, dl, TLI.getPointerTy(), Index); 954 955 // Calculate the element offset and add it to the pointer. 956 unsigned EltSize = EltVT.getSizeInBits() / 8; // FIXME: should be ABI size. 957 958 Index = DAG.getNode(ISD::MUL, dl, Index.getValueType(), Index, 959 DAG.getConstant(EltSize, Index.getValueType())); 960 return DAG.getNode(ISD::ADD, dl, Index.getValueType(), Index, VecPtr); 961} 962 963/// JoinIntegers - Build an integer with low bits Lo and high bits Hi. 964SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) { 965 // Arbitrarily use dlHi for result DebugLoc 966 DebugLoc dlHi = Hi.getDebugLoc(); 967 DebugLoc dlLo = Lo.getDebugLoc(); 968 EVT LVT = Lo.getValueType(); 969 EVT HVT = Hi.getValueType(); 970 EVT NVT = EVT::getIntegerVT(LVT.getSizeInBits() + HVT.getSizeInBits()); 971 972 Lo = DAG.getNode(ISD::ZERO_EXTEND, dlLo, NVT, Lo); 973 Hi = DAG.getNode(ISD::ANY_EXTEND, dlHi, NVT, Hi); 974 Hi = DAG.getNode(ISD::SHL, dlHi, NVT, Hi, 975 DAG.getConstant(LVT.getSizeInBits(), TLI.getPointerTy())); 976 return DAG.getNode(ISD::OR, dlHi, NVT, Lo, Hi); 977} 978 979/// LibCallify - Convert the node into a libcall with the same prototype. 980SDValue DAGTypeLegalizer::LibCallify(RTLIB::Libcall LC, SDNode *N, 981 bool isSigned) { 982 unsigned NumOps = N->getNumOperands(); 983 DebugLoc dl = N->getDebugLoc(); 984 if (NumOps == 0) { 985 return MakeLibCall(LC, N->getValueType(0), 0, 0, isSigned, dl); 986 } else if (NumOps == 1) { 987 SDValue Op = N->getOperand(0); 988 return MakeLibCall(LC, N->getValueType(0), &Op, 1, isSigned, dl); 989 } else if (NumOps == 2) { 990 SDValue Ops[2] = { N->getOperand(0), N->getOperand(1) }; 991 return MakeLibCall(LC, N->getValueType(0), Ops, 2, isSigned, dl); 992 } 993 SmallVector<SDValue, 8> Ops(NumOps); 994 for (unsigned i = 0; i < NumOps; ++i) 995 Ops[i] = N->getOperand(i); 996 997 return MakeLibCall(LC, N->getValueType(0), &Ops[0], NumOps, isSigned, dl); 998} 999 1000/// MakeLibCall - Generate a libcall taking the given operands as arguments and 1001/// returning a result of type RetVT. 1002SDValue DAGTypeLegalizer::MakeLibCall(RTLIB::Libcall LC, EVT RetVT, 1003 const SDValue *Ops, unsigned NumOps, 1004 bool isSigned, DebugLoc dl) { 1005 TargetLowering::ArgListTy Args; 1006 Args.reserve(NumOps); 1007 1008 TargetLowering::ArgListEntry Entry; 1009 for (unsigned i = 0; i != NumOps; ++i) { 1010 Entry.Node = Ops[i]; 1011 Entry.Ty = Entry.Node.getValueType().getTypeForEVT(); 1012 Entry.isSExt = isSigned; 1013 Entry.isZExt = !isSigned; 1014 Args.push_back(Entry); 1015 } 1016 SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC), 1017 TLI.getPointerTy()); 1018 1019 const Type *RetTy = RetVT.getTypeForEVT(); 1020 std::pair<SDValue,SDValue> CallInfo = 1021 TLI.LowerCallTo(DAG.getEntryNode(), RetTy, isSigned, !isSigned, false, 1022 false, 0, CallingConv::C, false, 1023 /*isReturnValueUsed=*/true, 1024 Callee, Args, DAG, dl); 1025 return CallInfo.first; 1026} 1027 1028/// PromoteTargetBoolean - Promote the given target boolean to a target boolean 1029/// of the given type. A target boolean is an integer value, not necessarily of 1030/// type i1, the bits of which conform to getBooleanContents. 1031SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, EVT VT) { 1032 DebugLoc dl = Bool.getDebugLoc(); 1033 ISD::NodeType ExtendCode; 1034 switch (TLI.getBooleanContents()) { 1035 default: 1036 assert(false && "Unknown BooleanContent!"); 1037 case TargetLowering::UndefinedBooleanContent: 1038 // Extend to VT by adding rubbish bits. 1039 ExtendCode = ISD::ANY_EXTEND; 1040 break; 1041 case TargetLowering::ZeroOrOneBooleanContent: 1042 // Extend to VT by adding zero bits. 1043 ExtendCode = ISD::ZERO_EXTEND; 1044 break; 1045 case TargetLowering::ZeroOrNegativeOneBooleanContent: { 1046 // Extend to VT by copying the sign bit. 1047 ExtendCode = ISD::SIGN_EXTEND; 1048 break; 1049 } 1050 } 1051 return DAG.getNode(ExtendCode, dl, VT, Bool); 1052} 1053 1054/// SplitInteger - Return the lower LoVT bits of Op in Lo and the upper HiVT 1055/// bits in Hi. 1056void DAGTypeLegalizer::SplitInteger(SDValue Op, 1057 EVT LoVT, EVT HiVT, 1058 SDValue &Lo, SDValue &Hi) { 1059 DebugLoc dl = Op.getDebugLoc(); 1060 assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() == 1061 Op.getValueType().getSizeInBits() && "Invalid integer splitting!"); 1062 Lo = DAG.getNode(ISD::TRUNCATE, dl, LoVT, Op); 1063 Hi = DAG.getNode(ISD::SRL, dl, Op.getValueType(), Op, 1064 DAG.getConstant(LoVT.getSizeInBits(), TLI.getPointerTy())); 1065 Hi = DAG.getNode(ISD::TRUNCATE, dl, HiVT, Hi); 1066} 1067 1068/// SplitInteger - Return the lower and upper halves of Op's bits in a value 1069/// type half the size of Op's. 1070void DAGTypeLegalizer::SplitInteger(SDValue Op, 1071 SDValue &Lo, SDValue &Hi) { 1072 EVT HalfVT = EVT::getIntegerVT(Op.getValueType().getSizeInBits()/2); 1073 SplitInteger(Op, HalfVT, HalfVT, Lo, Hi); 1074} 1075 1076 1077//===----------------------------------------------------------------------===// 1078// Entry Point 1079//===----------------------------------------------------------------------===// 1080 1081/// LegalizeTypes - This transforms the SelectionDAG into a SelectionDAG that 1082/// only uses types natively supported by the target. Returns "true" if it made 1083/// any changes. 1084/// 1085/// Note that this is an involved process that may invalidate pointers into 1086/// the graph. 1087bool SelectionDAG::LegalizeTypes() { 1088 return DAGTypeLegalizer(*this).run(); 1089} 1090