1 //===- llvm/Analysis/LoopInfoImpl.h - Natural Loop Calculator ---*- C++ -*-===// 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 is the generic implementation of LoopInfo used for both Loops and 11 // MachineLoops. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_ANALYSIS_LOOPINFOIMPL_H 16 #define LLVM_ANALYSIS_LOOPINFOIMPL_H 17 18 #include "llvm/ADT/DepthFirstIterator.h" 19 #include "llvm/ADT/PostOrderIterator.h" 20 #include "llvm/ADT/STLExtras.h" 21 #include "llvm/ADT/SetVector.h" 22 #include "llvm/Analysis/LoopInfo.h" 23 #include "llvm/IR/Dominators.h" 24 25 namespace llvm { 26 27 //===----------------------------------------------------------------------===// 28 // APIs for simple analysis of the loop. See header notes. 29 30 /// getExitingBlocks - Return all blocks inside the loop that have successors 31 /// outside of the loop. These are the blocks _inside of the current loop_ 32 /// which branch out. The returned list is always unique. 33 /// 34 template<class BlockT, class LoopT> 35 void LoopBase<BlockT, LoopT>:: 36 getExitingBlocks(SmallVectorImpl<BlockT *> &ExitingBlocks) const { 37 for (const auto BB : blocks()) 38 for (const auto &Succ : children<BlockT*>(BB)) 39 if (!contains(Succ)) { 40 // Not in current loop? It must be an exit block. 41 ExitingBlocks.push_back(BB); 42 break; 43 } 44 } 45 46 /// getExitingBlock - If getExitingBlocks would return exactly one block, 47 /// return that block. Otherwise return null. 48 template<class BlockT, class LoopT> 49 BlockT *LoopBase<BlockT, LoopT>::getExitingBlock() const { 50 SmallVector<BlockT*, 8> ExitingBlocks; 51 getExitingBlocks(ExitingBlocks); 52 if (ExitingBlocks.size() == 1) 53 return ExitingBlocks[0]; 54 return nullptr; 55 } 56 57 /// getExitBlocks - Return all of the successor blocks of this loop. These 58 /// are the blocks _outside of the current loop_ which are branched to. 59 /// 60 template<class BlockT, class LoopT> 61 void LoopBase<BlockT, LoopT>:: 62 getExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const { 63 for (const auto BB : blocks()) 64 for (const auto &Succ : children<BlockT*>(BB)) 65 if (!contains(Succ)) 66 // Not in current loop? It must be an exit block. 67 ExitBlocks.push_back(Succ); 68 } 69 70 /// getExitBlock - If getExitBlocks would return exactly one block, 71 /// return that block. Otherwise return null. 72 template<class BlockT, class LoopT> 73 BlockT *LoopBase<BlockT, LoopT>::getExitBlock() const { 74 SmallVector<BlockT*, 8> ExitBlocks; 75 getExitBlocks(ExitBlocks); 76 if (ExitBlocks.size() == 1) 77 return ExitBlocks[0]; 78 return nullptr; 79 } 80 81 /// getExitEdges - Return all pairs of (_inside_block_,_outside_block_). 82 template<class BlockT, class LoopT> 83 void LoopBase<BlockT, LoopT>:: 84 getExitEdges(SmallVectorImpl<Edge> &ExitEdges) const { 85 for (const auto BB : blocks()) 86 for (const auto &Succ : children<BlockT*>(BB)) 87 if (!contains(Succ)) 88 // Not in current loop? It must be an exit block. 89 ExitEdges.emplace_back(BB, Succ); 90 } 91 92 /// getLoopPreheader - If there is a preheader for this loop, return it. A 93 /// loop has a preheader if there is only one edge to the header of the loop 94 /// from outside of the loop. If this is the case, the block branching to the 95 /// header of the loop is the preheader node. 96 /// 97 /// This method returns null if there is no preheader for the loop. 98 /// 99 template<class BlockT, class LoopT> 100 BlockT *LoopBase<BlockT, LoopT>::getLoopPreheader() const { 101 // Keep track of nodes outside the loop branching to the header... 102 BlockT *Out = getLoopPredecessor(); 103 if (!Out) return nullptr; 104 105 // Make sure there is only one exit out of the preheader. 106 typedef GraphTraits<BlockT*> BlockTraits; 107 typename BlockTraits::ChildIteratorType SI = BlockTraits::child_begin(Out); 108 ++SI; 109 if (SI != BlockTraits::child_end(Out)) 110 return nullptr; // Multiple exits from the block, must not be a preheader. 111 112 // The predecessor has exactly one successor, so it is a preheader. 113 return Out; 114 } 115 116 /// getLoopPredecessor - If the given loop's header has exactly one unique 117 /// predecessor outside the loop, return it. Otherwise return null. 118 /// This is less strict that the loop "preheader" concept, which requires 119 /// the predecessor to have exactly one successor. 120 /// 121 template<class BlockT, class LoopT> 122 BlockT *LoopBase<BlockT, LoopT>::getLoopPredecessor() const { 123 // Keep track of nodes outside the loop branching to the header... 124 BlockT *Out = nullptr; 125 126 // Loop over the predecessors of the header node... 127 BlockT *Header = getHeader(); 128 for (const auto Pred : children<Inverse<BlockT*>>(Header)) { 129 if (!contains(Pred)) { // If the block is not in the loop... 130 if (Out && Out != Pred) 131 return nullptr; // Multiple predecessors outside the loop 132 Out = Pred; 133 } 134 } 135 136 // Make sure there is only one exit out of the preheader. 137 assert(Out && "Header of loop has no predecessors from outside loop?"); 138 return Out; 139 } 140 141 /// getLoopLatch - If there is a single latch block for this loop, return it. 142 /// A latch block is a block that contains a branch back to the header. 143 template<class BlockT, class LoopT> 144 BlockT *LoopBase<BlockT, LoopT>::getLoopLatch() const { 145 BlockT *Header = getHeader(); 146 BlockT *Latch = nullptr; 147 for (const auto Pred : children<Inverse<BlockT*>>(Header)) { 148 if (contains(Pred)) { 149 if (Latch) return nullptr; 150 Latch = Pred; 151 } 152 } 153 154 return Latch; 155 } 156 157 //===----------------------------------------------------------------------===// 158 // APIs for updating loop information after changing the CFG 159 // 160 161 /// addBasicBlockToLoop - This method is used by other analyses to update loop 162 /// information. NewBB is set to be a new member of the current loop. 163 /// Because of this, it is added as a member of all parent loops, and is added 164 /// to the specified LoopInfo object as being in the current basic block. It 165 /// is not valid to replace the loop header with this method. 166 /// 167 template<class BlockT, class LoopT> 168 void LoopBase<BlockT, LoopT>:: 169 addBasicBlockToLoop(BlockT *NewBB, LoopInfoBase<BlockT, LoopT> &LIB) { 170 #ifndef NDEBUG 171 if (!Blocks.empty()) { 172 auto SameHeader = LIB[getHeader()]; 173 assert(contains(SameHeader) && getHeader() == SameHeader->getHeader() 174 && "Incorrect LI specified for this loop!"); 175 } 176 #endif 177 assert(NewBB && "Cannot add a null basic block to the loop!"); 178 assert(!LIB[NewBB] && "BasicBlock already in the loop!"); 179 180 LoopT *L = static_cast<LoopT *>(this); 181 182 // Add the loop mapping to the LoopInfo object... 183 LIB.BBMap[NewBB] = L; 184 185 // Add the basic block to this loop and all parent loops... 186 while (L) { 187 L->addBlockEntry(NewBB); 188 L = L->getParentLoop(); 189 } 190 } 191 192 /// replaceChildLoopWith - This is used when splitting loops up. It replaces 193 /// the OldChild entry in our children list with NewChild, and updates the 194 /// parent pointer of OldChild to be null and the NewChild to be this loop. 195 /// This updates the loop depth of the new child. 196 template<class BlockT, class LoopT> 197 void LoopBase<BlockT, LoopT>:: 198 replaceChildLoopWith(LoopT *OldChild, LoopT *NewChild) { 199 assert(OldChild->ParentLoop == this && "This loop is already broken!"); 200 assert(!NewChild->ParentLoop && "NewChild already has a parent!"); 201 typename std::vector<LoopT *>::iterator I = find(SubLoops, OldChild); 202 assert(I != SubLoops.end() && "OldChild not in loop!"); 203 *I = NewChild; 204 OldChild->ParentLoop = nullptr; 205 NewChild->ParentLoop = static_cast<LoopT *>(this); 206 } 207 208 /// verifyLoop - Verify loop structure 209 template<class BlockT, class LoopT> 210 void LoopBase<BlockT, LoopT>::verifyLoop() const { 211 #ifndef NDEBUG 212 assert(!Blocks.empty() && "Loop header is missing"); 213 214 // Setup for using a depth-first iterator to visit every block in the loop. 215 SmallVector<BlockT*, 8> ExitBBs; 216 getExitBlocks(ExitBBs); 217 df_iterator_default_set<BlockT*> VisitSet; 218 VisitSet.insert(ExitBBs.begin(), ExitBBs.end()); 219 df_ext_iterator<BlockT*, df_iterator_default_set<BlockT*>> 220 BI = df_ext_begin(getHeader(), VisitSet), 221 BE = df_ext_end(getHeader(), VisitSet); 222 223 // Keep track of the BBs visited. 224 SmallPtrSet<BlockT*, 8> VisitedBBs; 225 226 // Check the individual blocks. 227 for ( ; BI != BE; ++BI) { 228 BlockT *BB = *BI; 229 230 assert(std::any_of(GraphTraits<BlockT*>::child_begin(BB), 231 GraphTraits<BlockT*>::child_end(BB), 232 [&](BlockT *B){return contains(B);}) && 233 "Loop block has no in-loop successors!"); 234 235 assert(std::any_of(GraphTraits<Inverse<BlockT*> >::child_begin(BB), 236 GraphTraits<Inverse<BlockT*> >::child_end(BB), 237 [&](BlockT *B){return contains(B);}) && 238 "Loop block has no in-loop predecessors!"); 239 240 SmallVector<BlockT *, 2> OutsideLoopPreds; 241 std::for_each(GraphTraits<Inverse<BlockT*> >::child_begin(BB), 242 GraphTraits<Inverse<BlockT*> >::child_end(BB), 243 [&](BlockT *B){if (!contains(B)) 244 OutsideLoopPreds.push_back(B); 245 }); 246 247 if (BB == getHeader()) { 248 assert(!OutsideLoopPreds.empty() && "Loop is unreachable!"); 249 } else if (!OutsideLoopPreds.empty()) { 250 // A non-header loop shouldn't be reachable from outside the loop, 251 // though it is permitted if the predecessor is not itself actually 252 // reachable. 253 BlockT *EntryBB = &BB->getParent()->front(); 254 for (BlockT *CB : depth_first(EntryBB)) 255 for (unsigned i = 0, e = OutsideLoopPreds.size(); i != e; ++i) 256 assert(CB != OutsideLoopPreds[i] && 257 "Loop has multiple entry points!"); 258 } 259 assert(BB != &getHeader()->getParent()->front() && 260 "Loop contains function entry block!"); 261 262 VisitedBBs.insert(BB); 263 } 264 265 if (VisitedBBs.size() != getNumBlocks()) { 266 dbgs() << "The following blocks are unreachable in the loop: "; 267 for (auto BB : Blocks) { 268 if (!VisitedBBs.count(BB)) { 269 dbgs() << *BB << "\n"; 270 } 271 } 272 assert(false && "Unreachable block in loop"); 273 } 274 275 // Check the subloops. 276 for (iterator I = begin(), E = end(); I != E; ++I) 277 // Each block in each subloop should be contained within this loop. 278 for (block_iterator BI = (*I)->block_begin(), BE = (*I)->block_end(); 279 BI != BE; ++BI) { 280 assert(contains(*BI) && 281 "Loop does not contain all the blocks of a subloop!"); 282 } 283 284 // Check the parent loop pointer. 285 if (ParentLoop) { 286 assert(is_contained(*ParentLoop, this) && 287 "Loop is not a subloop of its parent!"); 288 } 289 #endif 290 } 291 292 /// verifyLoop - Verify loop structure of this loop and all nested loops. 293 template<class BlockT, class LoopT> 294 void LoopBase<BlockT, LoopT>::verifyLoopNest( 295 DenseSet<const LoopT*> *Loops) const { 296 Loops->insert(static_cast<const LoopT *>(this)); 297 // Verify this loop. 298 verifyLoop(); 299 // Verify the subloops. 300 for (iterator I = begin(), E = end(); I != E; ++I) 301 (*I)->verifyLoopNest(Loops); 302 } 303 304 template<class BlockT, class LoopT> 305 void LoopBase<BlockT, LoopT>::print(raw_ostream &OS, unsigned Depth, 306 bool Verbose) const { 307 OS.indent(Depth*2) << "Loop at depth " << getLoopDepth() 308 << " containing: "; 309 310 BlockT *H = getHeader(); 311 for (unsigned i = 0; i < getBlocks().size(); ++i) { 312 BlockT *BB = getBlocks()[i]; 313 if (!Verbose) { 314 if (i) OS << ","; 315 BB->printAsOperand(OS, false); 316 } else OS << "\n"; 317 318 if (BB == H) OS << "<header>"; 319 if (isLoopLatch(BB)) OS << "<latch>"; 320 if (isLoopExiting(BB)) OS << "<exiting>"; 321 if (Verbose) 322 BB->print(OS); 323 } 324 OS << "\n"; 325 326 for (iterator I = begin(), E = end(); I != E; ++I) 327 (*I)->print(OS, Depth+2); 328 } 329 330 //===----------------------------------------------------------------------===// 331 /// Stable LoopInfo Analysis - Build a loop tree using stable iterators so the 332 /// result does / not depend on use list (block predecessor) order. 333 /// 334 335 /// Discover a subloop with the specified backedges such that: All blocks within 336 /// this loop are mapped to this loop or a subloop. And all subloops within this 337 /// loop have their parent loop set to this loop or a subloop. 338 template<class BlockT, class LoopT> 339 static void discoverAndMapSubloop(LoopT *L, ArrayRef<BlockT*> Backedges, 340 LoopInfoBase<BlockT, LoopT> *LI, 341 const DominatorTreeBase<BlockT> &DomTree) { 342 typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits; 343 344 unsigned NumBlocks = 0; 345 unsigned NumSubloops = 0; 346 347 // Perform a backward CFG traversal using a worklist. 348 std::vector<BlockT *> ReverseCFGWorklist(Backedges.begin(), Backedges.end()); 349 while (!ReverseCFGWorklist.empty()) { 350 BlockT *PredBB = ReverseCFGWorklist.back(); 351 ReverseCFGWorklist.pop_back(); 352 353 LoopT *Subloop = LI->getLoopFor(PredBB); 354 if (!Subloop) { 355 if (!DomTree.isReachableFromEntry(PredBB)) 356 continue; 357 358 // This is an undiscovered block. Map it to the current loop. 359 LI->changeLoopFor(PredBB, L); 360 ++NumBlocks; 361 if (PredBB == L->getHeader()) 362 continue; 363 // Push all block predecessors on the worklist. 364 ReverseCFGWorklist.insert(ReverseCFGWorklist.end(), 365 InvBlockTraits::child_begin(PredBB), 366 InvBlockTraits::child_end(PredBB)); 367 } 368 else { 369 // This is a discovered block. Find its outermost discovered loop. 370 while (LoopT *Parent = Subloop->getParentLoop()) 371 Subloop = Parent; 372 373 // If it is already discovered to be a subloop of this loop, continue. 374 if (Subloop == L) 375 continue; 376 377 // Discover a subloop of this loop. 378 Subloop->setParentLoop(L); 379 ++NumSubloops; 380 NumBlocks += Subloop->getBlocks().capacity(); 381 PredBB = Subloop->getHeader(); 382 // Continue traversal along predecessors that are not loop-back edges from 383 // within this subloop tree itself. Note that a predecessor may directly 384 // reach another subloop that is not yet discovered to be a subloop of 385 // this loop, which we must traverse. 386 for (const auto Pred : children<Inverse<BlockT*>>(PredBB)) { 387 if (LI->getLoopFor(Pred) != Subloop) 388 ReverseCFGWorklist.push_back(Pred); 389 } 390 } 391 } 392 L->getSubLoopsVector().reserve(NumSubloops); 393 L->reserveBlocks(NumBlocks); 394 } 395 396 /// Populate all loop data in a stable order during a single forward DFS. 397 template<class BlockT, class LoopT> 398 class PopulateLoopsDFS { 399 typedef GraphTraits<BlockT*> BlockTraits; 400 typedef typename BlockTraits::ChildIteratorType SuccIterTy; 401 402 LoopInfoBase<BlockT, LoopT> *LI; 403 public: 404 PopulateLoopsDFS(LoopInfoBase<BlockT, LoopT> *li): 405 LI(li) {} 406 407 void traverse(BlockT *EntryBlock); 408 409 protected: 410 void insertIntoLoop(BlockT *Block); 411 }; 412 413 /// Top-level driver for the forward DFS within the loop. 414 template<class BlockT, class LoopT> 415 void PopulateLoopsDFS<BlockT, LoopT>::traverse(BlockT *EntryBlock) { 416 for (BlockT *BB : post_order(EntryBlock)) 417 insertIntoLoop(BB); 418 } 419 420 /// Add a single Block to its ancestor loops in PostOrder. If the block is a 421 /// subloop header, add the subloop to its parent in PostOrder, then reverse the 422 /// Block and Subloop vectors of the now complete subloop to achieve RPO. 423 template<class BlockT, class LoopT> 424 void PopulateLoopsDFS<BlockT, LoopT>::insertIntoLoop(BlockT *Block) { 425 LoopT *Subloop = LI->getLoopFor(Block); 426 if (Subloop && Block == Subloop->getHeader()) { 427 // We reach this point once per subloop after processing all the blocks in 428 // the subloop. 429 if (Subloop->getParentLoop()) 430 Subloop->getParentLoop()->getSubLoopsVector().push_back(Subloop); 431 else 432 LI->addTopLevelLoop(Subloop); 433 434 // For convenience, Blocks and Subloops are inserted in postorder. Reverse 435 // the lists, except for the loop header, which is always at the beginning. 436 Subloop->reverseBlock(1); 437 std::reverse(Subloop->getSubLoopsVector().begin(), 438 Subloop->getSubLoopsVector().end()); 439 440 Subloop = Subloop->getParentLoop(); 441 } 442 for (; Subloop; Subloop = Subloop->getParentLoop()) 443 Subloop->addBlockEntry(Block); 444 } 445 446 /// Analyze LoopInfo discovers loops during a postorder DominatorTree traversal 447 /// interleaved with backward CFG traversals within each subloop 448 /// (discoverAndMapSubloop). The backward traversal skips inner subloops, so 449 /// this part of the algorithm is linear in the number of CFG edges. Subloop and 450 /// Block vectors are then populated during a single forward CFG traversal 451 /// (PopulateLoopDFS). 452 /// 453 /// During the two CFG traversals each block is seen three times: 454 /// 1) Discovered and mapped by a reverse CFG traversal. 455 /// 2) Visited during a forward DFS CFG traversal. 456 /// 3) Reverse-inserted in the loop in postorder following forward DFS. 457 /// 458 /// The Block vectors are inclusive, so step 3 requires loop-depth number of 459 /// insertions per block. 460 template<class BlockT, class LoopT> 461 void LoopInfoBase<BlockT, LoopT>:: 462 analyze(const DominatorTreeBase<BlockT> &DomTree) { 463 464 // Postorder traversal of the dominator tree. 465 const DomTreeNodeBase<BlockT> *DomRoot = DomTree.getRootNode(); 466 for (auto DomNode : post_order(DomRoot)) { 467 468 BlockT *Header = DomNode->getBlock(); 469 SmallVector<BlockT *, 4> Backedges; 470 471 // Check each predecessor of the potential loop header. 472 for (const auto Backedge : children<Inverse<BlockT*>>(Header)) { 473 // If Header dominates predBB, this is a new loop. Collect the backedges. 474 if (DomTree.dominates(Header, Backedge) 475 && DomTree.isReachableFromEntry(Backedge)) { 476 Backedges.push_back(Backedge); 477 } 478 } 479 // Perform a backward CFG traversal to discover and map blocks in this loop. 480 if (!Backedges.empty()) { 481 LoopT *L = new LoopT(Header); 482 discoverAndMapSubloop(L, ArrayRef<BlockT*>(Backedges), this, DomTree); 483 } 484 } 485 // Perform a single forward CFG traversal to populate block and subloop 486 // vectors for all loops. 487 PopulateLoopsDFS<BlockT, LoopT> DFS(this); 488 DFS.traverse(DomRoot->getBlock()); 489 } 490 491 template <class BlockT, class LoopT> 492 SmallVector<LoopT *, 4> LoopInfoBase<BlockT, LoopT>::getLoopsInPreorder() { 493 SmallVector<LoopT *, 4> PreOrderLoops, PreOrderWorklist; 494 // The outer-most loop actually goes into the result in the same relative 495 // order as we walk it. But LoopInfo stores the top level loops in reverse 496 // program order so for here we reverse it to get forward program order. 497 // FIXME: If we change the order of LoopInfo we will want to remove the 498 // reverse here. 499 for (LoopT *RootL : reverse(*this)) { 500 assert(PreOrderWorklist.empty() && 501 "Must start with an empty preorder walk worklist."); 502 PreOrderWorklist.push_back(RootL); 503 do { 504 LoopT *L = PreOrderWorklist.pop_back_val(); 505 // Sub-loops are stored in forward program order, but will process the 506 // worklist backwards so append them in reverse order. 507 PreOrderWorklist.append(L->rbegin(), L->rend()); 508 PreOrderLoops.push_back(L); 509 } while (!PreOrderWorklist.empty()); 510 } 511 512 return PreOrderLoops; 513 } 514 515 template <class BlockT, class LoopT> 516 SmallVector<LoopT *, 4> 517 LoopInfoBase<BlockT, LoopT>::getLoopsInReverseSiblingPreorder() { 518 SmallVector<LoopT *, 4> PreOrderLoops, PreOrderWorklist; 519 // The outer-most loop actually goes into the result in the same relative 520 // order as we walk it. LoopInfo stores the top level loops in reverse 521 // program order so we walk in order here. 522 // FIXME: If we change the order of LoopInfo we will want to add a reverse 523 // here. 524 for (LoopT *RootL : *this) { 525 assert(PreOrderWorklist.empty() && 526 "Must start with an empty preorder walk worklist."); 527 PreOrderWorklist.push_back(RootL); 528 do { 529 LoopT *L = PreOrderWorklist.pop_back_val(); 530 // Sub-loops are stored in forward program order, but will process the 531 // worklist backwards so we can just append them in order. 532 PreOrderWorklist.append(L->begin(), L->end()); 533 PreOrderLoops.push_back(L); 534 } while (!PreOrderWorklist.empty()); 535 } 536 537 return PreOrderLoops; 538 } 539 540 // Debugging 541 template<class BlockT, class LoopT> 542 void LoopInfoBase<BlockT, LoopT>::print(raw_ostream &OS) const { 543 for (unsigned i = 0; i < TopLevelLoops.size(); ++i) 544 TopLevelLoops[i]->print(OS); 545 #if 0 546 for (DenseMap<BasicBlock*, LoopT*>::const_iterator I = BBMap.begin(), 547 E = BBMap.end(); I != E; ++I) 548 OS << "BB '" << I->first->getName() << "' level = " 549 << I->second->getLoopDepth() << "\n"; 550 #endif 551 } 552 553 template <typename T> 554 bool compareVectors(std::vector<T> &BB1, std::vector<T> &BB2) { 555 std::sort(BB1.begin(), BB1.end()); 556 std::sort(BB2.begin(), BB2.end()); 557 return BB1 == BB2; 558 } 559 560 template <class BlockT, class LoopT> 561 void addInnerLoopsToHeadersMap(DenseMap<BlockT *, const LoopT *> &LoopHeaders, 562 const LoopInfoBase<BlockT, LoopT> &LI, 563 const LoopT &L) { 564 LoopHeaders[L.getHeader()] = &L; 565 for (LoopT *SL : L) 566 addInnerLoopsToHeadersMap(LoopHeaders, LI, *SL); 567 } 568 569 #ifndef NDEBUG 570 template <class BlockT, class LoopT> 571 static void compareLoops(const LoopT *L, const LoopT *OtherL, 572 DenseMap<BlockT *, const LoopT *> &OtherLoopHeaders) { 573 BlockT *H = L->getHeader(); 574 BlockT *OtherH = OtherL->getHeader(); 575 assert(H == OtherH && 576 "Mismatched headers even though found in the same map entry!"); 577 578 assert(L->getLoopDepth() == OtherL->getLoopDepth() && 579 "Mismatched loop depth!"); 580 const LoopT *ParentL = L, *OtherParentL = OtherL; 581 do { 582 assert(ParentL->getHeader() == OtherParentL->getHeader() && 583 "Mismatched parent loop headers!"); 584 ParentL = ParentL->getParentLoop(); 585 OtherParentL = OtherParentL->getParentLoop(); 586 } while (ParentL); 587 588 for (const LoopT *SubL : *L) { 589 BlockT *SubH = SubL->getHeader(); 590 const LoopT *OtherSubL = OtherLoopHeaders.lookup(SubH); 591 assert(OtherSubL && "Inner loop is missing in computed loop info!"); 592 OtherLoopHeaders.erase(SubH); 593 compareLoops(SubL, OtherSubL, OtherLoopHeaders); 594 } 595 596 std::vector<BlockT *> BBs = L->getBlocks(); 597 std::vector<BlockT *> OtherBBs = OtherL->getBlocks(); 598 assert(compareVectors(BBs, OtherBBs) && 599 "Mismatched basic blocks in the loops!"); 600 } 601 #endif 602 603 template <class BlockT, class LoopT> 604 void LoopInfoBase<BlockT, LoopT>::verify( 605 const DominatorTreeBase<BlockT> &DomTree) const { 606 DenseSet<const LoopT*> Loops; 607 for (iterator I = begin(), E = end(); I != E; ++I) { 608 assert(!(*I)->getParentLoop() && "Top-level loop has a parent!"); 609 (*I)->verifyLoopNest(&Loops); 610 } 611 612 // Verify that blocks are mapped to valid loops. 613 #ifndef NDEBUG 614 for (auto &Entry : BBMap) { 615 const BlockT *BB = Entry.first; 616 LoopT *L = Entry.second; 617 assert(Loops.count(L) && "orphaned loop"); 618 assert(L->contains(BB) && "orphaned block"); 619 } 620 621 // Recompute LoopInfo to verify loops structure. 622 LoopInfoBase<BlockT, LoopT> OtherLI; 623 OtherLI.analyze(DomTree); 624 625 // Build a map we can use to move from our LI to the computed one. This 626 // allows us to ignore the particular order in any layer of the loop forest 627 // while still comparing the structure. 628 DenseMap<BlockT *, const LoopT *> OtherLoopHeaders; 629 for (LoopT *L : OtherLI) 630 addInnerLoopsToHeadersMap(OtherLoopHeaders, OtherLI, *L); 631 632 // Walk the top level loops and ensure there is a corresponding top-level 633 // loop in the computed version and then recursively compare those loop 634 // nests. 635 for (LoopT *L : *this) { 636 BlockT *Header = L->getHeader(); 637 const LoopT *OtherL = OtherLoopHeaders.lookup(Header); 638 assert(OtherL && "Top level loop is missing in computed loop info!"); 639 // Now that we've matched this loop, erase its header from the map. 640 OtherLoopHeaders.erase(Header); 641 // And recursively compare these loops. 642 compareLoops(L, OtherL, OtherLoopHeaders); 643 } 644 645 // Any remaining entries in the map are loops which were found when computing 646 // a fresh LoopInfo but not present in the current one. 647 if (!OtherLoopHeaders.empty()) { 648 for (const auto &HeaderAndLoop : OtherLoopHeaders) 649 dbgs() << "Found new loop: " << *HeaderAndLoop.second << "\n"; 650 llvm_unreachable("Found new loops when recomputing LoopInfo!"); 651 } 652 #endif 653 } 654 655 } // End llvm namespace 656 657 #endif 658