LegalizeTypes.cpp revision 2ecf88d1751c847b87a7119bf34fff85a3d272e2
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/Target/TargetData.h" 21using namespace llvm; 22 23static cl::opt<bool> 24EnableExpensiveChecks("enable-legalize-types-checking", cl::Hidden); 25 26/// PerformExpensiveChecks - Do extensive, expensive, sanity checking. 27void DAGTypeLegalizer::PerformExpensiveChecks() { 28 // If a node is not processed, then none of its values should be mapped by any 29 // of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues. 30 31 // If a node is processed, then each value with an illegal type must be mapped 32 // by exactly one of PromotedIntegers, ExpandedIntegers, ..., ReplacedValues. 33 // Values with a legal type may be mapped by ReplacedValues, but not by any of 34 // the other maps. 35 36 // Note that these invariants may not hold momentarily when processing a node: 37 // the node being processed may be put in a map before being marked Processed. 38 39 // Note that it is possible to have nodes marked NewNode in the DAG. This can 40 // occur in two ways. Firstly, a node may be created during legalization but 41 // never passed to the legalization core. This is usually due to the implicit 42 // folding that occurs when using the DAG.getNode operators. Secondly, a new 43 // node may be passed to the legalization core, but when analyzed may morph 44 // into a different node, leaving the original node as a NewNode in the DAG. 45 // A node may morph if one of its operands changes during analysis. Whether 46 // it actually morphs or not depends on whether, after updating its operands, 47 // it is equivalent to an existing node: if so, it morphs into that existing 48 // node (CSE). An operand can change during analysis if the operand is a new 49 // node that morphs, or it is a processed value that was mapped to some other 50 // value (as recorded in ReplacedValues) in which case the operand is turned 51 // into that other value. If a node morphs then the node it morphed into will 52 // be used instead of it for legalization, however the original node continues 53 // to live on in the DAG. 54 // The conclusion is that though there may be nodes marked NewNode in the DAG, 55 // all uses of such nodes are also marked NewNode: the result is a fungus of 56 // NewNodes growing on top of the useful nodes, and perhaps using them, but 57 // not used by them. 58 59 // If a value is mapped by ReplacedValues, then it must have no uses, except 60 // by nodes marked NewNode (see above). 61 62 // The final node obtained by mapping by ReplacedValues is not marked NewNode. 63 // Note that ReplacedValues should be applied iteratively. 64 65 // Note that the ReplacedValues map may also map deleted nodes. By iterating 66 // over the DAG we only consider non-deleted nodes. 67 SmallVector<SDNode*, 16> NewNodes; 68 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 69 E = DAG.allnodes_end(); I != E; ++I) { 70 // Remember nodes marked NewNode - they are subject to extra checking below. 71 if (I->getNodeId() == NewNode) 72 NewNodes.push_back(I); 73 74 for (unsigned i = 0, e = I->getNumValues(); i != e; ++i) { 75 SDValue Res(I, i); 76 bool Failed = false; 77 78 unsigned Mapped = 0; 79 if (ReplacedValues.find(Res) != ReplacedValues.end()) { 80 Mapped |= 1; 81 // Check that remapped values are only used by nodes marked NewNode. 82 for (SDNode::use_iterator UI = I->use_begin(), UE = I->use_end(); 83 UI != UE; ++UI) 84 if (UI.getUse().getSDValue().getResNo() == i) 85 assert(UI->getNodeId() == NewNode && 86 "Remapped value has non-trivial use!"); 87 88 // Check that the final result of applying ReplacedValues is not 89 // marked NewNode. 90 SDValue NewVal = ReplacedValues[Res]; 91 DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(NewVal); 92 while (I != ReplacedValues.end()) { 93 NewVal = I->second; 94 I = ReplacedValues.find(NewVal); 95 } 96 assert(NewVal.getNode()->getNodeId() != NewNode && 97 "ReplacedValues maps to a new node!"); 98 } 99 if (PromotedIntegers.find(Res) != PromotedIntegers.end()) 100 Mapped |= 2; 101 if (SoftenedFloats.find(Res) != SoftenedFloats.end()) 102 Mapped |= 4; 103 if (ScalarizedVectors.find(Res) != ScalarizedVectors.end()) 104 Mapped |= 8; 105 if (ExpandedIntegers.find(Res) != ExpandedIntegers.end()) 106 Mapped |= 16; 107 if (ExpandedFloats.find(Res) != ExpandedFloats.end()) 108 Mapped |= 32; 109 if (SplitVectors.find(Res) != SplitVectors.end()) 110 Mapped |= 64; 111 if (WidenedVectors.find(Res) != WidenedVectors.end()) 112 Mapped |= 128; 113 114 if (I->getNodeId() != Processed) { 115 if (Mapped != 0) { 116 cerr << "Unprocessed value in a map!"; 117 Failed = true; 118 } 119 } else if (isTypeLegal(Res.getValueType()) || IgnoreNodeResults(I)) { 120 // FIXME: Because of PR2957, the build vector can be placed on this 121 // list but if the associated vector shuffle is split, the build vector 122 // can also be split so we allow this to go through for now. 123 if (Mapped > 1 && Res.getOpcode() != ISD::BUILD_VECTOR) { 124 cerr << "Value with legal type was transformed!"; 125 Failed = true; 126 } 127 } else { 128 if (Mapped == 0) { 129 cerr << "Processed value not in any map!"; 130 Failed = true; 131 } else if (Mapped & (Mapped - 1)) { 132 cerr << "Value in multiple maps!"; 133 Failed = true; 134 } 135 } 136 137 if (Failed) { 138 if (Mapped & 1) 139 cerr << " ReplacedValues"; 140 if (Mapped & 2) 141 cerr << " PromotedIntegers"; 142 if (Mapped & 4) 143 cerr << " SoftenedFloats"; 144 if (Mapped & 8) 145 cerr << " ScalarizedVectors"; 146 if (Mapped & 16) 147 cerr << " ExpandedIntegers"; 148 if (Mapped & 32) 149 cerr << " ExpandedFloats"; 150 if (Mapped & 64) 151 cerr << " SplitVectors"; 152 if (Mapped & 128) 153 cerr << " WidenedVectors"; 154 cerr << "\n"; 155 abort(); 156 } 157 } 158 } 159 160 // Checked that NewNodes are only used by other NewNodes. 161 for (unsigned i = 0, e = NewNodes.size(); i != e; ++i) { 162 SDNode *N = NewNodes[i]; 163 for (SDNode::use_iterator UI = N->use_begin(), UE = N->use_end(); 164 UI != UE; ++UI) 165 assert(UI->getNodeId() == NewNode && "NewNode used by non-NewNode!"); 166 } 167} 168 169/// run - This is the main entry point for the type legalizer. This does a 170/// top-down traversal of the dag, legalizing types as it goes. Returns "true" 171/// if it made any changes. 172bool DAGTypeLegalizer::run() { 173 bool Changed = false; 174 175 // Create a dummy node (which is not added to allnodes), that adds a reference 176 // to the root node, preventing it from being deleted, and tracking any 177 // changes of the root. 178 HandleSDNode Dummy(DAG.getRoot()); 179 Dummy.setNodeId(Unanalyzed); 180 181 // The root of the dag may dangle to deleted nodes until the type legalizer is 182 // done. Set it to null to avoid confusion. 183 DAG.setRoot(SDValue()); 184 185 // Walk all nodes in the graph, assigning them a NodeId of 'ReadyToProcess' 186 // (and remembering them) if they are leaves and assigning 'Unanalyzed' if 187 // non-leaves. 188 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 189 E = DAG.allnodes_end(); I != E; ++I) { 190 if (I->getNumOperands() == 0) { 191 I->setNodeId(ReadyToProcess); 192 Worklist.push_back(I); 193 } else { 194 I->setNodeId(Unanalyzed); 195 } 196 } 197 198 // Now that we have a set of nodes to process, handle them all. 199 while (!Worklist.empty()) { 200#ifndef XDEBUG 201 if (EnableExpensiveChecks) 202#endif 203 PerformExpensiveChecks(); 204 205 SDNode *N = Worklist.back(); 206 Worklist.pop_back(); 207 assert(N->getNodeId() == ReadyToProcess && 208 "Node should be ready if on worklist!"); 209 210 if (IgnoreNodeResults(N)) 211 goto ScanOperands; 212 213 // Scan the values produced by the node, checking to see if any result 214 // types are illegal. 215 for (unsigned i = 0, NumResults = N->getNumValues(); i < NumResults; ++i) { 216 MVT ResultVT = N->getValueType(i); 217 switch (getTypeAction(ResultVT)) { 218 default: 219 assert(false && "Unknown action!"); 220 case Legal: 221 break; 222 // The following calls must take care of *all* of the node's results, 223 // not just the illegal result they were passed (this includes results 224 // with a legal type). Results can be remapped using ReplaceValueWith, 225 // or their promoted/expanded/etc values registered in PromotedIntegers, 226 // ExpandedIntegers etc. 227 case PromoteInteger: 228 PromoteIntegerResult(N, i); 229 Changed = true; 230 goto NodeDone; 231 case ExpandInteger: 232 ExpandIntegerResult(N, i); 233 Changed = true; 234 goto NodeDone; 235 case SoftenFloat: 236 SoftenFloatResult(N, i); 237 Changed = true; 238 goto NodeDone; 239 case ExpandFloat: 240 ExpandFloatResult(N, i); 241 Changed = true; 242 goto NodeDone; 243 case ScalarizeVector: 244 ScalarizeVectorResult(N, i); 245 Changed = true; 246 goto NodeDone; 247 case SplitVector: 248 SplitVectorResult(N, i); 249 Changed = true; 250 goto NodeDone; 251 case WidenVector: 252 WidenVectorResult(N, i); 253 Changed = true; 254 goto NodeDone; 255 } 256 } 257 258ScanOperands: 259 // Scan the operand list for the node, handling any nodes with operands that 260 // are illegal. 261 { 262 unsigned NumOperands = N->getNumOperands(); 263 bool NeedsReanalyzing = false; 264 unsigned i; 265 for (i = 0; i != NumOperands; ++i) { 266 if (IgnoreNodeResults(N->getOperand(i).getNode())) 267 continue; 268 269 if (N->getOpcode() == ISD::VECTOR_SHUFFLE && i == 2) { 270 // The shuffle mask doesn't need to be a legal vector type. 271 // FIXME: We can remove this once we fix PR2957. 272 SetIgnoredNodeResult(N->getOperand(2).getNode()); 273 continue; 274 } 275 276 MVT 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 N->setNodeId(ReadyToProcess); 333 assert(N->getNumValues() == M->getNumValues() && 334 "Node morphing changed the number of results!"); 335 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 336 // Replacing the value takes care of remapping the new value. 337 ReplaceValueWith(SDValue(N, i), SDValue(M, i)); 338 // Fall through. 339 } 340 341 if (i == NumOperands) { 342 DEBUG(cerr << "Legally typed node: "; N->dump(&DAG); cerr << "\n"); 343 } 344 } 345NodeDone: 346 347 // If we reach here, the node was processed, potentially creating new nodes. 348 // Mark it as processed and add its users to the worklist as appropriate. 349 assert(N->getNodeId() == ReadyToProcess && "Node ID recalculated?"); 350 N->setNodeId(Processed); 351 352 for (SDNode::use_iterator UI = N->use_begin(), E = N->use_end(); 353 UI != E; ++UI) { 354 SDNode *User = *UI; 355 int NodeId = User->getNodeId(); 356 357 // This node has two options: it can either be a new node or its Node ID 358 // may be a count of the number of operands it has that are not ready. 359 if (NodeId > 0) { 360 User->setNodeId(NodeId-1); 361 362 // If this was the last use it was waiting on, add it to the ready list. 363 if (NodeId-1 == ReadyToProcess) 364 Worklist.push_back(User); 365 continue; 366 } 367 368 // If this is an unreachable new node, then ignore it. If it ever becomes 369 // reachable by being used by a newly created node then it will be handled 370 // by AnalyzeNewNode. 371 if (NodeId == NewNode) 372 continue; 373 374 // Otherwise, this node is new: this is the first operand of it that 375 // became ready. Its new NodeId is the number of operands it has minus 1 376 // (as this node is now processed). 377 assert(NodeId == Unanalyzed && "Unknown node ID!"); 378 User->setNodeId(User->getNumOperands() - 1); 379 380 // If the node only has a single operand, it is now ready. 381 if (User->getNumOperands() == 1) 382 Worklist.push_back(User); 383 } 384 } 385 386#ifndef XDEBUG 387 if (EnableExpensiveChecks) 388#endif 389 PerformExpensiveChecks(); 390 391 // If the root changed (e.g. it was a dead load) update the root. 392 DAG.setRoot(Dummy.getValue()); 393 394 // Remove dead nodes. This is important to do for cleanliness but also before 395 // the checking loop below. Implicit folding by the DAG.getNode operators and 396 // node morphing can cause unreachable nodes to be around with their flags set 397 // to new. 398 DAG.RemoveDeadNodes(); 399 400 // In a debug build, scan all the nodes to make sure we found them all. This 401 // ensures that there are no cycles and that everything got processed. 402#ifndef NDEBUG 403 for (SelectionDAG::allnodes_iterator I = DAG.allnodes_begin(), 404 E = DAG.allnodes_end(); I != E; ++I) { 405 bool Failed = false; 406 407 // Check that all result types are legal. 408 if (!IgnoreNodeResults(I)) 409 for (unsigned i = 0, NumVals = I->getNumValues(); i < NumVals; ++i) 410 if (!isTypeLegal(I->getValueType(i))) { 411 cerr << "Result type " << i << " illegal!\n"; 412 Failed = true; 413 } 414 415 // Check that all operand types are legal. 416 for (unsigned i = 0, NumOps = I->getNumOperands(); i < NumOps; ++i) 417 if (!IgnoreNodeResults(I->getOperand(i).getNode()) && 418 !isTypeLegal(I->getOperand(i).getValueType())) { 419 cerr << "Operand type " << i << " illegal!\n"; 420 Failed = true; 421 } 422 423 if (I->getNodeId() != Processed) { 424 if (I->getNodeId() == NewNode) 425 cerr << "New node not analyzed?\n"; 426 else if (I->getNodeId() == Unanalyzed) 427 cerr << "Unanalyzed node not noticed?\n"; 428 else if (I->getNodeId() > 0) 429 cerr << "Operand not processed?\n"; 430 else if (I->getNodeId() == ReadyToProcess) 431 cerr << "Not added to worklist?\n"; 432 Failed = true; 433 } 434 435 if (Failed) { 436 I->dump(&DAG); cerr << "\n"; 437 abort(); 438 } 439 } 440#endif 441 442 return Changed; 443} 444 445/// AnalyzeNewNode - The specified node is the root of a subtree of potentially 446/// new nodes. Correct any processed operands (this may change the node) and 447/// calculate the NodeId. If the node itself changes to a processed node, it 448/// is not remapped - the caller needs to take care of this. 449/// Returns the potentially changed node. 450SDNode *DAGTypeLegalizer::AnalyzeNewNode(SDNode *N) { 451 // If this was an existing node that is already done, we're done. 452 if (N->getNodeId() != NewNode && N->getNodeId() != Unanalyzed) 453 return N; 454 455 // Remove any stale map entries. 456 ExpungeNode(N); 457 458 // Okay, we know that this node is new. Recursively walk all of its operands 459 // to see if they are new also. The depth of this walk is bounded by the size 460 // of the new tree that was constructed (usually 2-3 nodes), so we don't worry 461 // about revisiting of nodes. 462 // 463 // As we walk the operands, keep track of the number of nodes that are 464 // processed. If non-zero, this will become the new nodeid of this node. 465 // Operands may morph when they are analyzed. If so, the node will be 466 // updated after all operands have been analyzed. Since this is rare, 467 // the code tries to minimize overhead in the non-morphing case. 468 469 SmallVector<SDValue, 8> NewOps; 470 unsigned NumProcessed = 0; 471 for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) { 472 SDValue OrigOp = N->getOperand(i); 473 SDValue Op = OrigOp; 474 475 AnalyzeNewValue(Op); // Op may morph. 476 477 if (Op.getNode()->getNodeId() == Processed) 478 ++NumProcessed; 479 480 if (!NewOps.empty()) { 481 // Some previous operand changed. Add this one to the list. 482 NewOps.push_back(Op); 483 } else if (Op != OrigOp) { 484 // This is the first operand to change - add all operands so far. 485 for (unsigned j = 0; j < i; ++j) 486 NewOps.push_back(N->getOperand(j)); 487 NewOps.push_back(Op); 488 } 489 } 490 491 // Some operands changed - update the node. 492 if (!NewOps.empty()) { 493 SDNode *M = DAG.UpdateNodeOperands(SDValue(N, 0), &NewOps[0], 494 NewOps.size()).getNode(); 495 if (M != N) { 496 // The node morphed into a different node. Normally for this to happen 497 // the original node would have to be marked NewNode. However this can 498 // in theory momentarily not be the case while ReplaceValueWith is doing 499 // its stuff. Mark the original node NewNode to help sanity checking. 500 N->setNodeId(NewNode); 501 if (M->getNodeId() != NewNode && M->getNodeId() != Unanalyzed) 502 // It morphed into a previously analyzed node - nothing more to do. 503 return M; 504 505 // It morphed into a different new node. Do the equivalent of passing 506 // it to AnalyzeNewNode: expunge it and calculate the NodeId. No need 507 // to remap the operands, since they are the same as the operands we 508 // remapped above. 509 N = M; 510 ExpungeNode(N); 511 } 512 } 513 514 // Calculate the NodeId. 515 N->setNodeId(N->getNumOperands() - NumProcessed); 516 if (N->getNodeId() == ReadyToProcess) 517 Worklist.push_back(N); 518 519 return N; 520} 521 522/// AnalyzeNewValue - Call AnalyzeNewNode, updating the node in Val if needed. 523/// If the node changes to a processed node, then remap it. 524void DAGTypeLegalizer::AnalyzeNewValue(SDValue &Val) { 525 Val.setNode(AnalyzeNewNode(Val.getNode())); 526 if (Val.getNode()->getNodeId() == Processed) 527 // We were passed a processed node, or it morphed into one - remap it. 528 RemapValue(Val); 529} 530 531/// ExpungeNode - If N has a bogus mapping in ReplacedValues, eliminate it. 532/// This can occur when a node is deleted then reallocated as a new node - 533/// the mapping in ReplacedValues applies to the deleted node, not the new 534/// one. 535/// The only map that can have a deleted node as a source is ReplacedValues. 536/// Other maps can have deleted nodes as targets, but since their looked-up 537/// values are always immediately remapped using RemapValue, resulting in a 538/// not-deleted node, this is harmless as long as ReplacedValues/RemapValue 539/// always performs correct mappings. In order to keep the mapping correct, 540/// ExpungeNode should be called on any new nodes *before* adding them as 541/// either source or target to ReplacedValues (which typically means calling 542/// Expunge when a new node is first seen, since it may no longer be marked 543/// NewNode by the time it is added to ReplacedValues). 544void DAGTypeLegalizer::ExpungeNode(SDNode *N) { 545 if (N->getNodeId() != NewNode) 546 return; 547 548 // If N is not remapped by ReplacedValues then there is nothing to do. 549 unsigned i, e; 550 for (i = 0, e = N->getNumValues(); i != e; ++i) 551 if (ReplacedValues.find(SDValue(N, i)) != ReplacedValues.end()) 552 break; 553 554 if (i == e) 555 return; 556 557 // Remove N from all maps - this is expensive but rare. 558 559 for (DenseMap<SDValue, SDValue>::iterator I = PromotedIntegers.begin(), 560 E = PromotedIntegers.end(); I != E; ++I) { 561 assert(I->first.getNode() != N); 562 RemapValue(I->second); 563 } 564 565 for (DenseMap<SDValue, SDValue>::iterator I = SoftenedFloats.begin(), 566 E = SoftenedFloats.end(); I != E; ++I) { 567 assert(I->first.getNode() != N); 568 RemapValue(I->second); 569 } 570 571 for (DenseMap<SDValue, SDValue>::iterator I = ScalarizedVectors.begin(), 572 E = ScalarizedVectors.end(); I != E; ++I) { 573 assert(I->first.getNode() != N); 574 RemapValue(I->second); 575 } 576 577 for (DenseMap<SDValue, SDValue>::iterator I = WidenedVectors.begin(), 578 E = WidenedVectors.end(); I != E; ++I) { 579 assert(I->first.getNode() != N); 580 RemapValue(I->second); 581 } 582 583 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 584 I = ExpandedIntegers.begin(), E = ExpandedIntegers.end(); I != E; ++I){ 585 assert(I->first.getNode() != N); 586 RemapValue(I->second.first); 587 RemapValue(I->second.second); 588 } 589 590 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 591 I = ExpandedFloats.begin(), E = ExpandedFloats.end(); I != E; ++I) { 592 assert(I->first.getNode() != N); 593 RemapValue(I->second.first); 594 RemapValue(I->second.second); 595 } 596 597 for (DenseMap<SDValue, std::pair<SDValue, SDValue> >::iterator 598 I = SplitVectors.begin(), E = SplitVectors.end(); I != E; ++I) { 599 assert(I->first.getNode() != N); 600 RemapValue(I->second.first); 601 RemapValue(I->second.second); 602 } 603 604 for (DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.begin(), 605 E = ReplacedValues.end(); I != E; ++I) 606 RemapValue(I->second); 607 608 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) 609 ReplacedValues.erase(SDValue(N, i)); 610} 611 612/// RemapValue - If the specified value was already legalized to another value, 613/// replace it by that value. 614void DAGTypeLegalizer::RemapValue(SDValue &N) { 615 DenseMap<SDValue, SDValue>::iterator I = ReplacedValues.find(N); 616 if (I != ReplacedValues.end()) { 617 // Use path compression to speed up future lookups if values get multiply 618 // replaced with other values. 619 RemapValue(I->second); 620 N = I->second; 621 assert(N.getNode()->getNodeId() != NewNode && "Mapped to new node!"); 622 } 623} 624 625namespace { 626 /// NodeUpdateListener - This class is a DAGUpdateListener that listens for 627 /// updates to nodes and recomputes their ready state. 628 class VISIBILITY_HIDDEN NodeUpdateListener : 629 public SelectionDAG::DAGUpdateListener { 630 DAGTypeLegalizer &DTL; 631 SmallSetVector<SDNode*, 16> &NodesToAnalyze; 632 public: 633 explicit NodeUpdateListener(DAGTypeLegalizer &dtl, 634 SmallSetVector<SDNode*, 16> &nta) 635 : DTL(dtl), NodesToAnalyze(nta) {} 636 637 virtual void NodeDeleted(SDNode *N, SDNode *E) { 638 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 639 N->getNodeId() != DAGTypeLegalizer::Processed && 640 "Invalid node ID for RAUW deletion!"); 641 // It is possible, though rare, for the deleted node N to occur as a 642 // target in a map, so note the replacement N -> E in ReplacedValues. 643 assert(E && "Node not replaced?"); 644 DTL.NoteDeletion(N, E); 645 646 // In theory the deleted node could also have been scheduled for analysis. 647 // So add it to the set of nodes which will not be analyzed. 648 NodesToAnalyze.remove(N); 649 650 // In general nothing needs to be done for E, since it didn't change but 651 // only gained new uses. However N -> E was just added to ReplacedValues, 652 // and the result of a ReplacedValues mapping is not allowed to be marked 653 // NewNode. So if E is marked NewNode, then it needs to be analyzed. 654 if (E->getNodeId() == DAGTypeLegalizer::NewNode) 655 NodesToAnalyze.insert(E); 656 } 657 658 virtual void NodeUpdated(SDNode *N) { 659 // Node updates can mean pretty much anything. It is possible that an 660 // operand was set to something already processed (f.e.) in which case 661 // this node could become ready. Recompute its flags. 662 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 663 N->getNodeId() != DAGTypeLegalizer::Processed && 664 "Invalid node ID for RAUW deletion!"); 665 NodesToAnalyze.insert(N); 666 } 667 }; 668} 669 670 671/// ReplaceValueWith - The specified value was legalized to the specified other 672/// value. Update the DAG and NodeIds replacing any uses of From to use To 673/// instead. 674void DAGTypeLegalizer::ReplaceValueWith(SDValue From, SDValue To) { 675 assert(From.getNode()->getNodeId() == ReadyToProcess && 676 "Only the node being processed may be remapped!"); 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(); 697 698 // Analyze the node's operands and recalculate the node ID. 699 assert(N->getNodeId() != DAGTypeLegalizer::ReadyToProcess && 700 N->getNodeId() != DAGTypeLegalizer::Processed && 701 "Invalid node ID for RAUW analysis!"); 702 N->setNodeId(NewNode); 703 SDNode *M = AnalyzeNewNode(N); 704 if (M != N) { 705 // The node morphed into a different node. Make everyone use the new node 706 // instead. 707 assert(M->getNodeId() != NewNode && "Analysis resulted in NewNode!"); 708 assert(N->getNumValues() == M->getNumValues() && 709 "Node morphing changed the number of results!"); 710 for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) { 711 SDValue OldVal(N, i); 712 SDValue NewVal(M, i); 713 if (M->getNodeId() == Processed) 714 RemapValue(NewVal); 715 DAG.ReplaceAllUsesOfValueWith(OldVal, NewVal, &NUL); 716 } 717 // The original node continues to exist in the DAG, marked NewNode. 718 } 719 } 720} 721 722void DAGTypeLegalizer::SetPromotedInteger(SDValue Op, SDValue Result) { 723 AnalyzeNewValue(Result); 724 725 SDValue &OpEntry = PromotedIntegers[Op]; 726 assert(OpEntry.getNode() == 0 && "Node is already promoted!"); 727 OpEntry = Result; 728} 729 730void DAGTypeLegalizer::SetSoftenedFloat(SDValue Op, SDValue Result) { 731 AnalyzeNewValue(Result); 732 733 SDValue &OpEntry = SoftenedFloats[Op]; 734 assert(OpEntry.getNode() == 0 && "Node is already converted to integer!"); 735 OpEntry = Result; 736} 737 738void DAGTypeLegalizer::SetScalarizedVector(SDValue Op, SDValue Result) { 739 AnalyzeNewValue(Result); 740 741 SDValue &OpEntry = ScalarizedVectors[Op]; 742 assert(OpEntry.getNode() == 0 && "Node is already scalarized!"); 743 OpEntry = Result; 744} 745 746void DAGTypeLegalizer::GetExpandedInteger(SDValue Op, SDValue &Lo, 747 SDValue &Hi) { 748 std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op]; 749 RemapValue(Entry.first); 750 RemapValue(Entry.second); 751 assert(Entry.first.getNode() && "Operand isn't expanded"); 752 Lo = Entry.first; 753 Hi = Entry.second; 754} 755 756void DAGTypeLegalizer::SetExpandedInteger(SDValue Op, SDValue Lo, 757 SDValue Hi) { 758 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 759 AnalyzeNewValue(Lo); 760 AnalyzeNewValue(Hi); 761 762 // Remember that this is the result of the node. 763 std::pair<SDValue, SDValue> &Entry = ExpandedIntegers[Op]; 764 assert(Entry.first.getNode() == 0 && "Node already expanded"); 765 Entry.first = Lo; 766 Entry.second = Hi; 767} 768 769void DAGTypeLegalizer::GetExpandedFloat(SDValue Op, SDValue &Lo, 770 SDValue &Hi) { 771 std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op]; 772 RemapValue(Entry.first); 773 RemapValue(Entry.second); 774 assert(Entry.first.getNode() && "Operand isn't expanded"); 775 Lo = Entry.first; 776 Hi = Entry.second; 777} 778 779void DAGTypeLegalizer::SetExpandedFloat(SDValue Op, SDValue Lo, 780 SDValue Hi) { 781 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 782 AnalyzeNewValue(Lo); 783 AnalyzeNewValue(Hi); 784 785 // Remember that this is the result of the node. 786 std::pair<SDValue, SDValue> &Entry = ExpandedFloats[Op]; 787 assert(Entry.first.getNode() == 0 && "Node already expanded"); 788 Entry.first = Lo; 789 Entry.second = Hi; 790} 791 792void DAGTypeLegalizer::GetSplitVector(SDValue Op, SDValue &Lo, 793 SDValue &Hi) { 794 std::pair<SDValue, SDValue> &Entry = SplitVectors[Op]; 795 RemapValue(Entry.first); 796 RemapValue(Entry.second); 797 assert(Entry.first.getNode() && "Operand isn't split"); 798 Lo = Entry.first; 799 Hi = Entry.second; 800} 801 802void DAGTypeLegalizer::SetSplitVector(SDValue Op, SDValue Lo, 803 SDValue Hi) { 804 // Lo/Hi may have been newly allocated, if so, add nodeid's as relevant. 805 AnalyzeNewValue(Lo); 806 AnalyzeNewValue(Hi); 807 808 // Remember that this is the result of the node. 809 std::pair<SDValue, SDValue> &Entry = SplitVectors[Op]; 810 assert(Entry.first.getNode() == 0 && "Node already split"); 811 Entry.first = Lo; 812 Entry.second = Hi; 813} 814 815void DAGTypeLegalizer::SetWidenedVector(SDValue Op, SDValue Result) { 816 AnalyzeNewValue(Result); 817 818 SDValue &OpEntry = WidenedVectors[Op]; 819 assert(OpEntry.getNode() == 0 && "Node already widened!"); 820 OpEntry = Result; 821} 822 823// Set to ignore result 824void DAGTypeLegalizer::SetIgnoredNodeResult(SDNode* N) { 825 IgnoredNodesResultsSet.insert(N); 826} 827 828//===----------------------------------------------------------------------===// 829// Utilities. 830//===----------------------------------------------------------------------===// 831 832/// BitConvertToInteger - Convert to an integer of the same size. 833SDValue DAGTypeLegalizer::BitConvertToInteger(SDValue Op) { 834 unsigned BitWidth = Op.getValueType().getSizeInBits(); 835 return DAG.getNode(ISD::BIT_CONVERT, MVT::getIntegerVT(BitWidth), Op); 836} 837 838SDValue DAGTypeLegalizer::CreateStackStoreLoad(SDValue Op, 839 MVT DestVT) { 840 // Create the stack frame object. Make sure it is aligned for both 841 // the source and destination types. 842 SDValue StackPtr = DAG.CreateStackTemporary(Op.getValueType(), DestVT); 843 // Emit a store to the stack slot. 844 SDValue Store = DAG.getStore(DAG.getEntryNode(), Op, StackPtr, NULL, 0); 845 // Result is a load from the stack slot. 846 return DAG.getLoad(DestVT, Store, StackPtr, NULL, 0); 847} 848 849/// CustomLowerResults - Replace the node's results with custom code provided 850/// by the target and return "true", or do nothing and return "false". 851bool DAGTypeLegalizer::CustomLowerResults(SDNode *N, unsigned ResNo) { 852 // See if the target wants to custom lower this node. 853 if (TLI.getOperationAction(N->getOpcode(), N->getValueType(ResNo)) != 854 TargetLowering::Custom) 855 return false; 856 857 SmallVector<SDValue, 8> Results; 858 TLI.ReplaceNodeResults(N, Results, DAG); 859 if (Results.empty()) 860 // The target didn't want to custom lower it after all. 861 return false; 862 863 // Make everything that once used N's values now use those in Results instead. 864 assert(Results.size() == N->getNumValues() && 865 "Custom lowering returned the wrong number of results!"); 866 for (unsigned i = 0, e = Results.size(); i != e; ++i) 867 ReplaceValueWith(SDValue(N, i), Results[i]); 868 return true; 869} 870 871/// GetSplitDestVTs - Compute the VTs needed for the low/hi parts of a type 872/// which is split into two not necessarily identical pieces. 873void DAGTypeLegalizer::GetSplitDestVTs(MVT InVT, MVT &LoVT, MVT &HiVT) { 874 if (!InVT.isVector()) { 875 LoVT = HiVT = TLI.getTypeToTransformTo(InVT); 876 } else { 877 MVT NewEltVT = InVT.getVectorElementType(); 878 unsigned NumElements = InVT.getVectorNumElements(); 879 if ((NumElements & (NumElements-1)) == 0) { // Simple power of two vector. 880 NumElements >>= 1; 881 LoVT = HiVT = MVT::getVectorVT(NewEltVT, NumElements); 882 } else { // Non-power-of-two vectors. 883 unsigned NewNumElts_Lo = 1 << Log2_32(NumElements); 884 unsigned NewNumElts_Hi = NumElements - NewNumElts_Lo; 885 LoVT = MVT::getVectorVT(NewEltVT, NewNumElts_Lo); 886 HiVT = MVT::getVectorVT(NewEltVT, NewNumElts_Hi); 887 } 888 } 889} 890 891SDValue DAGTypeLegalizer::GetVectorElementPointer(SDValue VecPtr, MVT EltVT, 892 SDValue Index) { 893 // Make sure the index type is big enough to compute in. 894 if (Index.getValueType().bitsGT(TLI.getPointerTy())) 895 Index = DAG.getNode(ISD::TRUNCATE, TLI.getPointerTy(), Index); 896 else 897 Index = DAG.getNode(ISD::ZERO_EXTEND, TLI.getPointerTy(), Index); 898 899 // Calculate the element offset and add it to the pointer. 900 unsigned EltSize = EltVT.getSizeInBits() / 8; // FIXME: should be ABI size. 901 902 Index = DAG.getNode(ISD::MUL, Index.getValueType(), Index, 903 DAG.getConstant(EltSize, Index.getValueType())); 904 return DAG.getNode(ISD::ADD, Index.getValueType(), Index, VecPtr); 905} 906 907/// JoinIntegers - Build an integer with low bits Lo and high bits Hi. 908SDValue DAGTypeLegalizer::JoinIntegers(SDValue Lo, SDValue Hi) { 909 MVT LVT = Lo.getValueType(); 910 MVT HVT = Hi.getValueType(); 911 MVT NVT = MVT::getIntegerVT(LVT.getSizeInBits() + HVT.getSizeInBits()); 912 913 Lo = DAG.getNode(ISD::ZERO_EXTEND, NVT, Lo); 914 Hi = DAG.getNode(ISD::ANY_EXTEND, NVT, Hi); 915 Hi = DAG.getNode(ISD::SHL, NVT, Hi, DAG.getConstant(LVT.getSizeInBits(), 916 TLI.getShiftAmountTy())); 917 return DAG.getNode(ISD::OR, NVT, Lo, Hi); 918} 919 920/// LibCallify - Convert the node into a libcall with the same prototype. 921SDValue DAGTypeLegalizer::LibCallify(RTLIB::Libcall LC, SDNode *N, 922 bool isSigned) { 923 unsigned NumOps = N->getNumOperands(); 924 if (NumOps == 0) { 925 return MakeLibCall(LC, N->getValueType(0), 0, 0, isSigned); 926 } else if (NumOps == 1) { 927 SDValue Op = N->getOperand(0); 928 return MakeLibCall(LC, N->getValueType(0), &Op, 1, isSigned); 929 } else if (NumOps == 2) { 930 SDValue Ops[2] = { N->getOperand(0), N->getOperand(1) }; 931 return MakeLibCall(LC, N->getValueType(0), Ops, 2, isSigned); 932 } 933 SmallVector<SDValue, 8> Ops(NumOps); 934 for (unsigned i = 0; i < NumOps; ++i) 935 Ops[i] = N->getOperand(i); 936 937 return MakeLibCall(LC, N->getValueType(0), &Ops[0], NumOps, isSigned); 938} 939 940/// MakeLibCall - Generate a libcall taking the given operands as arguments and 941/// returning a result of type RetVT. 942SDValue DAGTypeLegalizer::MakeLibCall(RTLIB::Libcall LC, MVT RetVT, 943 const SDValue *Ops, unsigned NumOps, 944 bool isSigned) { 945 TargetLowering::ArgListTy Args; 946 Args.reserve(NumOps); 947 948 TargetLowering::ArgListEntry Entry; 949 for (unsigned i = 0; i != NumOps; ++i) { 950 Entry.Node = Ops[i]; 951 Entry.Ty = Entry.Node.getValueType().getTypeForMVT(); 952 Entry.isSExt = isSigned; 953 Entry.isZExt = !isSigned; 954 Args.push_back(Entry); 955 } 956 SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC), 957 TLI.getPointerTy()); 958 959 const Type *RetTy = RetVT.getTypeForMVT(); 960 std::pair<SDValue,SDValue> CallInfo = 961 TLI.LowerCallTo(DAG.getEntryNode(), RetTy, isSigned, !isSigned, false, 962 false, CallingConv::C, false, Callee, Args, DAG); 963 return CallInfo.first; 964} 965 966/// PromoteTargetBoolean - Promote the given target boolean to a target boolean 967/// of the given type. A target boolean is an integer value, not necessarily of 968/// type i1, the bits of which conform to getBooleanContents. 969SDValue DAGTypeLegalizer::PromoteTargetBoolean(SDValue Bool, MVT VT) { 970 ISD::NodeType ExtendCode; 971 switch (TLI.getBooleanContents()) { 972 default: 973 assert(false && "Unknown BooleanContent!"); 974 case TargetLowering::UndefinedBooleanContent: 975 // Extend to VT by adding rubbish bits. 976 ExtendCode = ISD::ANY_EXTEND; 977 break; 978 case TargetLowering::ZeroOrOneBooleanContent: 979 // Extend to VT by adding zero bits. 980 ExtendCode = ISD::ZERO_EXTEND; 981 break; 982 case TargetLowering::ZeroOrNegativeOneBooleanContent: { 983 // Extend to VT by copying the sign bit. 984 ExtendCode = ISD::SIGN_EXTEND; 985 break; 986 } 987 } 988 return DAG.getNode(ExtendCode, VT, Bool); 989} 990 991/// SplitInteger - Return the lower LoVT bits of Op in Lo and the upper HiVT 992/// bits in Hi. 993void DAGTypeLegalizer::SplitInteger(SDValue Op, 994 MVT LoVT, MVT HiVT, 995 SDValue &Lo, SDValue &Hi) { 996 assert(LoVT.getSizeInBits() + HiVT.getSizeInBits() == 997 Op.getValueType().getSizeInBits() && "Invalid integer splitting!"); 998 Lo = DAG.getNode(ISD::TRUNCATE, LoVT, Op); 999 Hi = DAG.getNode(ISD::SRL, Op.getValueType(), Op, 1000 DAG.getConstant(LoVT.getSizeInBits(), 1001 TLI.getShiftAmountTy())); 1002 Hi = DAG.getNode(ISD::TRUNCATE, HiVT, Hi); 1003} 1004 1005/// SplitInteger - Return the lower and upper halves of Op's bits in a value 1006/// type half the size of Op's. 1007void DAGTypeLegalizer::SplitInteger(SDValue Op, 1008 SDValue &Lo, SDValue &Hi) { 1009 MVT HalfVT = MVT::getIntegerVT(Op.getValueType().getSizeInBits()/2); 1010 SplitInteger(Op, HalfVT, HalfVT, Lo, Hi); 1011} 1012 1013 1014//===----------------------------------------------------------------------===// 1015// Entry Point 1016//===----------------------------------------------------------------------===// 1017 1018/// LegalizeTypes - This transforms the SelectionDAG into a SelectionDAG that 1019/// only uses types natively supported by the target. Returns "true" if it made 1020/// any changes. 1021/// 1022/// Note that this is an involved process that may invalidate pointers into 1023/// the graph. 1024bool SelectionDAG::LegalizeTypes() { 1025 return DAGTypeLegalizer(*this).run(); 1026} 1027