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LoopInfoImpl.h
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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 
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/Analysis/LoopInfo.h"
21 
22 namespace llvm {
23 
24 //===----------------------------------------------------------------------===//
25 // APIs for simple analysis of the loop. See header notes.
26 
27 /// getExitingBlocks - Return all blocks inside the loop that have successors
28 /// outside of the loop. These are the blocks _inside of the current loop_
29 /// which branch out. The returned list is always unique.
30 ///
31 template<class BlockT, class LoopT>
34  typedef GraphTraits<BlockT*> BlockTraits;
35  for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI)
36  for (typename BlockTraits::ChildIteratorType I =
37  BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
38  I != E; ++I)
39  if (!contains(*I)) {
40  // Not in current loop? It must be an exit block.
41  ExitingBlocks.push_back(*BI);
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>
50  SmallVector<BlockT*, 8> ExitingBlocks;
51  getExitingBlocks(ExitingBlocks);
52  if (ExitingBlocks.size() == 1)
53  return ExitingBlocks[0];
54  return 0;
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>
63  typedef GraphTraits<BlockT*> BlockTraits;
64  for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI)
65  for (typename BlockTraits::ChildIteratorType I =
66  BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
67  I != E; ++I)
68  if (!contains(*I))
69  // Not in current loop? It must be an exit block.
70  ExitBlocks.push_back(*I);
71 }
72 
73 /// getExitBlock - If getExitBlocks would return exactly one block,
74 /// return that block. Otherwise return null.
75 template<class BlockT, class LoopT>
77  SmallVector<BlockT*, 8> ExitBlocks;
78  getExitBlocks(ExitBlocks);
79  if (ExitBlocks.size() == 1)
80  return ExitBlocks[0];
81  return 0;
82 }
83 
84 /// getExitEdges - Return all pairs of (_inside_block_,_outside_block_).
85 template<class BlockT, class LoopT>
88  typedef GraphTraits<BlockT*> BlockTraits;
89  for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI)
90  for (typename BlockTraits::ChildIteratorType I =
91  BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
92  I != E; ++I)
93  if (!contains(*I))
94  // Not in current loop? It must be an exit block.
95  ExitEdges.push_back(Edge(*BI, *I));
96 }
97 
98 /// getLoopPreheader - If there is a preheader for this loop, return it. A
99 /// loop has a preheader if there is only one edge to the header of the loop
100 /// from outside of the loop. If this is the case, the block branching to the
101 /// header of the loop is the preheader node.
102 ///
103 /// This method returns null if there is no preheader for the loop.
104 ///
105 template<class BlockT, class LoopT>
107  // Keep track of nodes outside the loop branching to the header...
108  BlockT *Out = getLoopPredecessor();
109  if (!Out) return 0;
110 
111  // Make sure there is only one exit out of the preheader.
112  typedef GraphTraits<BlockT*> BlockTraits;
113  typename BlockTraits::ChildIteratorType SI = BlockTraits::child_begin(Out);
114  ++SI;
115  if (SI != BlockTraits::child_end(Out))
116  return 0; // Multiple exits from the block, must not be a preheader.
117 
118  // The predecessor has exactly one successor, so it is a preheader.
119  return Out;
120 }
121 
122 /// getLoopPredecessor - If the given loop's header has exactly one unique
123 /// predecessor outside the loop, return it. Otherwise return null.
124 /// This is less strict that the loop "preheader" concept, which requires
125 /// the predecessor to have exactly one successor.
126 ///
127 template<class BlockT, class LoopT>
129  // Keep track of nodes outside the loop branching to the header...
130  BlockT *Out = 0;
131 
132  // Loop over the predecessors of the header node...
133  BlockT *Header = getHeader();
134  typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
135  for (typename InvBlockTraits::ChildIteratorType PI =
136  InvBlockTraits::child_begin(Header),
137  PE = InvBlockTraits::child_end(Header); PI != PE; ++PI) {
138  typename InvBlockTraits::NodeType *N = *PI;
139  if (!contains(N)) { // If the block is not in the loop...
140  if (Out && Out != N)
141  return 0; // Multiple predecessors outside the loop
142  Out = N;
143  }
144  }
145 
146  // Make sure there is only one exit out of the preheader.
147  assert(Out && "Header of loop has no predecessors from outside loop?");
148  return Out;
149 }
150 
151 /// getLoopLatch - If there is a single latch block for this loop, return it.
152 /// A latch block is a block that contains a branch back to the header.
153 template<class BlockT, class LoopT>
155  BlockT *Header = getHeader();
156  typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
157  typename InvBlockTraits::ChildIteratorType PI =
158  InvBlockTraits::child_begin(Header);
159  typename InvBlockTraits::ChildIteratorType PE =
160  InvBlockTraits::child_end(Header);
161  BlockT *Latch = 0;
162  for (; PI != PE; ++PI) {
163  typename InvBlockTraits::NodeType *N = *PI;
164  if (contains(N)) {
165  if (Latch) return 0;
166  Latch = N;
167  }
168  }
169 
170  return Latch;
171 }
172 
173 //===----------------------------------------------------------------------===//
174 // APIs for updating loop information after changing the CFG
175 //
176 
177 /// addBasicBlockToLoop - This method is used by other analyses to update loop
178 /// information. NewBB is set to be a new member of the current loop.
179 /// Because of this, it is added as a member of all parent loops, and is added
180 /// to the specified LoopInfo object as being in the current basic block. It
181 /// is not valid to replace the loop header with this method.
182 ///
183 template<class BlockT, class LoopT>
186  assert((Blocks.empty() || LIB[getHeader()] == this) &&
187  "Incorrect LI specified for this loop!");
188  assert(NewBB && "Cannot add a null basic block to the loop!");
189  assert(LIB[NewBB] == 0 && "BasicBlock already in the loop!");
190 
191  LoopT *L = static_cast<LoopT *>(this);
192 
193  // Add the loop mapping to the LoopInfo object...
194  LIB.BBMap[NewBB] = L;
195 
196  // Add the basic block to this loop and all parent loops...
197  while (L) {
198  L->addBlockEntry(NewBB);
199  L = L->getParentLoop();
200  }
201 }
202 
203 /// replaceChildLoopWith - This is used when splitting loops up. It replaces
204 /// the OldChild entry in our children list with NewChild, and updates the
205 /// parent pointer of OldChild to be null and the NewChild to be this loop.
206 /// This updates the loop depth of the new child.
207 template<class BlockT, class LoopT>
209 replaceChildLoopWith(LoopT *OldChild, LoopT *NewChild) {
210  assert(OldChild->ParentLoop == this && "This loop is already broken!");
211  assert(NewChild->ParentLoop == 0 && "NewChild already has a parent!");
212  typename std::vector<LoopT *>::iterator I =
213  std::find(SubLoops.begin(), SubLoops.end(), OldChild);
214  assert(I != SubLoops.end() && "OldChild not in loop!");
215  *I = NewChild;
216  OldChild->ParentLoop = 0;
217  NewChild->ParentLoop = static_cast<LoopT *>(this);
218 }
219 
220 /// verifyLoop - Verify loop structure
221 template<class BlockT, class LoopT>
223 #ifndef NDEBUG
224  assert(!Blocks.empty() && "Loop header is missing");
225 
226  // Setup for using a depth-first iterator to visit every block in the loop.
227  SmallVector<BlockT*, 8> ExitBBs;
228  getExitBlocks(ExitBBs);
230  VisitSet.insert(ExitBBs.begin(), ExitBBs.end());
232  BI = df_ext_begin(getHeader(), VisitSet),
233  BE = df_ext_end(getHeader(), VisitSet);
234 
235  // Keep track of the number of BBs visited.
236  unsigned NumVisited = 0;
237 
238  // Check the individual blocks.
239  for ( ; BI != BE; ++BI) {
240  BlockT *BB = *BI;
241  bool HasInsideLoopSuccs = false;
242  bool HasInsideLoopPreds = false;
243  SmallVector<BlockT *, 2> OutsideLoopPreds;
244 
245  typedef GraphTraits<BlockT*> BlockTraits;
246  for (typename BlockTraits::ChildIteratorType SI =
247  BlockTraits::child_begin(BB), SE = BlockTraits::child_end(BB);
248  SI != SE; ++SI)
249  if (contains(*SI)) {
250  HasInsideLoopSuccs = true;
251  break;
252  }
253  typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
254  for (typename InvBlockTraits::ChildIteratorType PI =
255  InvBlockTraits::child_begin(BB), PE = InvBlockTraits::child_end(BB);
256  PI != PE; ++PI) {
257  BlockT *N = *PI;
258  if (contains(N))
259  HasInsideLoopPreds = true;
260  else
261  OutsideLoopPreds.push_back(N);
262  }
263 
264  if (BB == getHeader()) {
265  assert(!OutsideLoopPreds.empty() && "Loop is unreachable!");
266  } else if (!OutsideLoopPreds.empty()) {
267  // A non-header loop shouldn't be reachable from outside the loop,
268  // though it is permitted if the predecessor is not itself actually
269  // reachable.
270  BlockT *EntryBB = BB->getParent()->begin();
271  for (df_iterator<BlockT *> NI = df_begin(EntryBB),
272  NE = df_end(EntryBB); NI != NE; ++NI)
273  for (unsigned i = 0, e = OutsideLoopPreds.size(); i != e; ++i)
274  assert(*NI != OutsideLoopPreds[i] &&
275  "Loop has multiple entry points!");
276  }
277  assert(HasInsideLoopPreds && "Loop block has no in-loop predecessors!");
278  assert(HasInsideLoopSuccs && "Loop block has no in-loop successors!");
279  assert(BB != getHeader()->getParent()->begin() &&
280  "Loop contains function entry block!");
281 
282  NumVisited++;
283  }
284 
285  assert(NumVisited == getNumBlocks() && "Unreachable block in loop");
286 
287  // Check the subloops.
288  for (iterator I = begin(), E = end(); I != E; ++I)
289  // Each block in each subloop should be contained within this loop.
290  for (block_iterator BI = (*I)->block_begin(), BE = (*I)->block_end();
291  BI != BE; ++BI) {
292  assert(contains(*BI) &&
293  "Loop does not contain all the blocks of a subloop!");
294  }
295 
296  // Check the parent loop pointer.
297  if (ParentLoop) {
298  assert(std::find(ParentLoop->begin(), ParentLoop->end(), this) !=
299  ParentLoop->end() &&
300  "Loop is not a subloop of its parent!");
301  }
302 #endif
303 }
304 
305 /// verifyLoop - Verify loop structure of this loop and all nested loops.
306 template<class BlockT, class LoopT>
308  DenseSet<const LoopT*> *Loops) const {
309  Loops->insert(static_cast<const LoopT *>(this));
310  // Verify this loop.
311  verifyLoop();
312  // Verify the subloops.
313  for (iterator I = begin(), E = end(); I != E; ++I)
314  (*I)->verifyLoopNest(Loops);
315 }
316 
317 template<class BlockT, class LoopT>
318 void LoopBase<BlockT, LoopT>::print(raw_ostream &OS, unsigned Depth) const {
319  OS.indent(Depth*2) << "Loop at depth " << getLoopDepth()
320  << " containing: ";
321 
322  for (unsigned i = 0; i < getBlocks().size(); ++i) {
323  if (i) OS << ",";
324  BlockT *BB = getBlocks()[i];
325  WriteAsOperand(OS, BB, false);
326  if (BB == getHeader()) OS << "<header>";
327  if (BB == getLoopLatch()) OS << "<latch>";
328  if (isLoopExiting(BB)) OS << "<exiting>";
329  }
330  OS << "\n";
331 
332  for (iterator I = begin(), E = end(); I != E; ++I)
333  (*I)->print(OS, Depth+2);
334 }
335 
336 //===----------------------------------------------------------------------===//
337 /// Stable LoopInfo Analysis - Build a loop tree using stable iterators so the
338 /// result does / not depend on use list (block predecessor) order.
339 ///
340 
341 /// Discover a subloop with the specified backedges such that: All blocks within
342 /// this loop are mapped to this loop or a subloop. And all subloops within this
343 /// loop have their parent loop set to this loop or a subloop.
344 template<class BlockT, class LoopT>
345 static void discoverAndMapSubloop(LoopT *L, ArrayRef<BlockT*> Backedges,
347  DominatorTreeBase<BlockT> &DomTree) {
348  typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
349 
350  unsigned NumBlocks = 0;
351  unsigned NumSubloops = 0;
352 
353  // Perform a backward CFG traversal using a worklist.
354  std::vector<BlockT *> ReverseCFGWorklist(Backedges.begin(), Backedges.end());
355  while (!ReverseCFGWorklist.empty()) {
356  BlockT *PredBB = ReverseCFGWorklist.back();
357  ReverseCFGWorklist.pop_back();
358 
359  LoopT *Subloop = LI->getLoopFor(PredBB);
360  if (!Subloop) {
361  if (!DomTree.isReachableFromEntry(PredBB))
362  continue;
363 
364  // This is an undiscovered block. Map it to the current loop.
365  LI->changeLoopFor(PredBB, L);
366  ++NumBlocks;
367  if (PredBB == L->getHeader())
368  continue;
369  // Push all block predecessors on the worklist.
370  ReverseCFGWorklist.insert(ReverseCFGWorklist.end(),
371  InvBlockTraits::child_begin(PredBB),
372  InvBlockTraits::child_end(PredBB));
373  }
374  else {
375  // This is a discovered block. Find its outermost discovered loop.
376  while (LoopT *Parent = Subloop->getParentLoop())
377  Subloop = Parent;
378 
379  // If it is already discovered to be a subloop of this loop, continue.
380  if (Subloop == L)
381  continue;
382 
383  // Discover a subloop of this loop.
384  Subloop->setParentLoop(L);
385  ++NumSubloops;
386  NumBlocks += Subloop->getBlocks().capacity();
387  PredBB = Subloop->getHeader();
388  // Continue traversal along predecessors that are not loop-back edges from
389  // within this subloop tree itself. Note that a predecessor may directly
390  // reach another subloop that is not yet discovered to be a subloop of
391  // this loop, which we must traverse.
392  for (typename InvBlockTraits::ChildIteratorType PI =
393  InvBlockTraits::child_begin(PredBB),
394  PE = InvBlockTraits::child_end(PredBB); PI != PE; ++PI) {
395  if (LI->getLoopFor(*PI) != Subloop)
396  ReverseCFGWorklist.push_back(*PI);
397  }
398  }
399  }
400  L->getSubLoopsVector().reserve(NumSubloops);
401  L->reserveBlocks(NumBlocks);
402 }
403 
404 namespace {
405 /// Populate all loop data in a stable order during a single forward DFS.
406 template<class BlockT, class LoopT>
407 class PopulateLoopsDFS {
408  typedef GraphTraits<BlockT*> BlockTraits;
409  typedef typename BlockTraits::ChildIteratorType SuccIterTy;
410 
411  LoopInfoBase<BlockT, LoopT> *LI;
412  DenseSet<const BlockT *> VisitedBlocks;
413  std::vector<std::pair<BlockT*, SuccIterTy> > DFSStack;
414 
415 public:
416  PopulateLoopsDFS(LoopInfoBase<BlockT, LoopT> *li):
417  LI(li) {}
418 
419  void traverse(BlockT *EntryBlock);
420 
421 protected:
422  void insertIntoLoop(BlockT *Block);
423 
424  BlockT *dfsSource() { return DFSStack.back().first; }
425  SuccIterTy &dfsSucc() { return DFSStack.back().second; }
426  SuccIterTy dfsSuccEnd() { return BlockTraits::child_end(dfsSource()); }
427 
428  void pushBlock(BlockT *Block) {
429  DFSStack.push_back(std::make_pair(Block, BlockTraits::child_begin(Block)));
430  }
431 };
432 } // anonymous
433 
434 /// Top-level driver for the forward DFS within the loop.
435 template<class BlockT, class LoopT>
436 void PopulateLoopsDFS<BlockT, LoopT>::traverse(BlockT *EntryBlock) {
437  pushBlock(EntryBlock);
438  VisitedBlocks.insert(EntryBlock);
439  while (!DFSStack.empty()) {
440  // Traverse the leftmost path as far as possible.
441  while (dfsSucc() != dfsSuccEnd()) {
442  BlockT *BB = *dfsSucc();
443  ++dfsSucc();
444  if (!VisitedBlocks.insert(BB).second)
445  continue;
446 
447  // Push the next DFS successor onto the stack.
448  pushBlock(BB);
449  }
450  // Visit the top of the stack in postorder and backtrack.
451  insertIntoLoop(dfsSource());
452  DFSStack.pop_back();
453  }
454 }
455 
456 /// Add a single Block to its ancestor loops in PostOrder. If the block is a
457 /// subloop header, add the subloop to its parent in PostOrder, then reverse the
458 /// Block and Subloop vectors of the now complete subloop to achieve RPO.
459 template<class BlockT, class LoopT>
460 void PopulateLoopsDFS<BlockT, LoopT>::insertIntoLoop(BlockT *Block) {
461  LoopT *Subloop = LI->getLoopFor(Block);
462  if (Subloop && Block == Subloop->getHeader()) {
463  // We reach this point once per subloop after processing all the blocks in
464  // the subloop.
465  if (Subloop->getParentLoop())
466  Subloop->getParentLoop()->getSubLoopsVector().push_back(Subloop);
467  else
468  LI->addTopLevelLoop(Subloop);
469 
470  // For convenience, Blocks and Subloops are inserted in postorder. Reverse
471  // the lists, except for the loop header, which is always at the beginning.
472  Subloop->reverseBlock(1);
473  std::reverse(Subloop->getSubLoopsVector().begin(),
474  Subloop->getSubLoopsVector().end());
475 
476  Subloop = Subloop->getParentLoop();
477  }
478  for (; Subloop; Subloop = Subloop->getParentLoop())
479  Subloop->addBlockEntry(Block);
480 }
481 
482 /// Analyze LoopInfo discovers loops during a postorder DominatorTree traversal
483 /// interleaved with backward CFG traversals within each subloop
484 /// (discoverAndMapSubloop). The backward traversal skips inner subloops, so
485 /// this part of the algorithm is linear in the number of CFG edges. Subloop and
486 /// Block vectors are then populated during a single forward CFG traversal
487 /// (PopulateLoopDFS).
488 ///
489 /// During the two CFG traversals each block is seen three times:
490 /// 1) Discovered and mapped by a reverse CFG traversal.
491 /// 2) Visited during a forward DFS CFG traversal.
492 /// 3) Reverse-inserted in the loop in postorder following forward DFS.
493 ///
494 /// The Block vectors are inclusive, so step 3 requires loop-depth number of
495 /// insertions per block.
496 template<class BlockT, class LoopT>
499 
500  // Postorder traversal of the dominator tree.
501  DomTreeNodeBase<BlockT>* DomRoot = DomTree.getRootNode();
502  for (po_iterator<DomTreeNodeBase<BlockT>*> DomIter = po_begin(DomRoot),
503  DomEnd = po_end(DomRoot); DomIter != DomEnd; ++DomIter) {
504 
505  BlockT *Header = DomIter->getBlock();
506  SmallVector<BlockT *, 4> Backedges;
507 
508  // Check each predecessor of the potential loop header.
509  typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
510  for (typename InvBlockTraits::ChildIteratorType PI =
511  InvBlockTraits::child_begin(Header),
512  PE = InvBlockTraits::child_end(Header); PI != PE; ++PI) {
513 
514  BlockT *Backedge = *PI;
515 
516  // If Header dominates predBB, this is a new loop. Collect the backedges.
517  if (DomTree.dominates(Header, Backedge)
518  && DomTree.isReachableFromEntry(Backedge)) {
519  Backedges.push_back(Backedge);
520  }
521  }
522  // Perform a backward CFG traversal to discover and map blocks in this loop.
523  if (!Backedges.empty()) {
524  LoopT *L = new LoopT(Header);
525  discoverAndMapSubloop(L, ArrayRef<BlockT*>(Backedges), this, DomTree);
526  }
527  }
528  // Perform a single forward CFG traversal to populate block and subloop
529  // vectors for all loops.
530  PopulateLoopsDFS<BlockT, LoopT> DFS(this);
531  DFS.traverse(DomRoot->getBlock());
532 }
533 
534 // Debugging
535 template<class BlockT, class LoopT>
537  for (unsigned i = 0; i < TopLevelLoops.size(); ++i)
538  TopLevelLoops[i]->print(OS);
539 #if 0
541  E = BBMap.end(); I != E; ++I)
542  OS << "BB '" << I->first->getName() << "' level = "
543  << I->second->getLoopDepth() << "\n";
544 #endif
545 }
546 
547 } // End llvm namespace
548 
549 #endif
const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:181
iterator end() const
Definition: ArrayRef.h:98
raw_ostream & indent(unsigned NumSpaces)
indent - Insert 'NumSpaces' spaces.
bool insert(PtrType Ptr)
Definition: SmallPtrSet.h:253
DenseSet< const BlockT * > VisitedBlocks
Definition: LoopInfoImpl.h:412
void replaceChildLoopWith(LoopT *OldChild, LoopT *NewChild)
Definition: LoopInfoImpl.h:209
const_iterator begin(StringRef path)
Get begin iterator over path.
Definition: Path.cpp:173
void changeLoopFor(BlockT *BB, LoopT *L)
Definition: LoopInfo.h:527
void print(raw_ostream &OS) const
Definition: LoopInfoImpl.h:536
DomTreeNodeBase< NodeT > * getRootNode()
Definition: Dominators.h:346
LoopT * getLoopFor(const BlockT *BB) const
Definition: LoopInfo.h:489
BlockT * getExitBlock() const
Definition: LoopInfoImpl.h:76
LoopInfoBase< BlockT, LoopT > * LI
Definition: LoopInfoImpl.h:411
BlockT * getLoopLatch() const
Definition: LoopInfoImpl.h:154
void getExitEdges(SmallVectorImpl< Edge > &ExitEdges) const
getExitEdges - Return all pairs of (inside_block,outside_block).
Definition: LoopInfoImpl.h:87
void WriteAsOperand(raw_ostream &, const Value *, bool PrintTy=true, const Module *Context=0)
Definition: AsmWriter.cpp:1179
void print(raw_ostream &OS, unsigned Depth=0) const
Definition: LoopInfoImpl.h:318
Hexagon Hardware Loops
void getExitingBlocks(SmallVectorImpl< BlockT * > &ExitingBlocks) const
Definition: LoopInfoImpl.h:33
po_iterator< T > po_begin(T G)
std::vector< std::pair< BlockT *, SuccIterTy > > DFSStack
Definition: LoopInfoImpl.h:413
void getExitBlocks(SmallVectorImpl< BlockT * > &ExitBlocks) const
Definition: LoopInfoImpl.h:62
void addBasicBlockToLoop(BlockT *NewBB, LoopInfoBase< BlockT, LoopT > &LI)
Definition: LoopInfoImpl.h:185
bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const
Definition: SmallVector.h:56
NodeT * getBlock() const
Definition: Dominators.h:82
void verifyLoop() const
verifyLoop - Verify loop structure
Definition: LoopInfoImpl.h:222
BlockT * getLoopPreheader() const
Definition: LoopInfoImpl.h:106
df_ext_iterator< T, SetTy > df_ext_end(const T &G, SetTy &S)
df_iterator< T > df_end(const T &G)
df_ext_iterator< T, SetTy > df_ext_begin(const T &G, SetTy &S)
iterator begin() const
Definition: ArrayRef.h:97
BlockT * getExitingBlock() const
Definition: LoopInfoImpl.h:49
std::pair< const BlockT *, const BlockT * > Edge
Edge type.
Definition: LoopInfo.h:206
std::pair< iterator, bool > insert(const ValueT &V)
Definition: DenseSet.h:117
df_iterator< T > df_begin(const T &G)
std::vector< BlockT * >::const_iterator block_iterator
Definition: LoopInfo.h:139
void verifyLoopNest(DenseSet< const LoopT * > *Loops) const
verifyLoop - Verify loop structure of this loop and all nested loops.
Definition: LoopInfoImpl.h:307
bool dominates(const DomTreeNodeBase< NodeT > *A, const DomTreeNodeBase< NodeT > *B)
Definition: Dominators.h:392
po_iterator< T > po_end(T G)
static void discoverAndMapSubloop(LoopT *L, ArrayRef< BlockT * > Backedges, LoopInfoBase< BlockT, LoopT > *LI, DominatorTreeBase< BlockT > &DomTree)
Definition: LoopInfoImpl.h:345
#define I(x, y, z)
Definition: MD5.cpp:54
#define N
void Analyze(DominatorTreeBase< BlockT > &DomTree)
Create the loop forest using a stable algorithm.
Definition: LoopInfoImpl.h:498
BlockT * getLoopPredecessor() const
Definition: LoopInfoImpl.h:128
bool isReachableFromEntry(const NodeT *A) const
Definition: Dominators.h:379
static const Function * getParent(const Value *V)
std::vector< LoopT * >::const_iterator iterator
Definition: LoopInfo.h:127