LLVM  4.0.0
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 
20 #include "llvm/ADT/SetVector.h"
21 #include "llvm/ADT/STLExtras.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>
37  typedef GraphTraits<BlockT*> BlockTraits;
38  for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI)
39  for (typename BlockTraits::ChildIteratorType I =
40  BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
41  I != E; ++I)
42  if (!contains(*I)) {
43  // Not in current loop? It must be an exit block.
44  ExitingBlocks.push_back(*BI);
45  break;
46  }
47 }
48 
49 /// getExitingBlock - If getExitingBlocks would return exactly one block,
50 /// return that block. Otherwise return null.
51 template<class BlockT, class LoopT>
53  SmallVector<BlockT*, 8> ExitingBlocks;
54  getExitingBlocks(ExitingBlocks);
55  if (ExitingBlocks.size() == 1)
56  return ExitingBlocks[0];
57  return nullptr;
58 }
59 
60 /// getExitBlocks - Return all of the successor blocks of this loop. These
61 /// are the blocks _outside of the current loop_ which are branched to.
62 ///
63 template<class BlockT, class LoopT>
66  typedef GraphTraits<BlockT*> BlockTraits;
67  for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI)
68  for (typename BlockTraits::ChildIteratorType I =
69  BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
70  I != E; ++I)
71  if (!contains(*I))
72  // Not in current loop? It must be an exit block.
73  ExitBlocks.push_back(*I);
74 }
75 
76 /// getExitBlock - If getExitBlocks would return exactly one block,
77 /// return that block. Otherwise return null.
78 template<class BlockT, class LoopT>
80  SmallVector<BlockT*, 8> ExitBlocks;
81  getExitBlocks(ExitBlocks);
82  if (ExitBlocks.size() == 1)
83  return ExitBlocks[0];
84  return nullptr;
85 }
86 
87 /// getExitEdges - Return all pairs of (_inside_block_,_outside_block_).
88 template<class BlockT, class LoopT>
91  typedef GraphTraits<BlockT*> BlockTraits;
92  for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI)
93  for (typename BlockTraits::ChildIteratorType I =
94  BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
95  I != E; ++I)
96  if (!contains(*I))
97  // Not in current loop? It must be an exit block.
98  ExitEdges.push_back(Edge(*BI, *I));
99 }
100 
101 /// getLoopPreheader - If there is a preheader for this loop, return it. A
102 /// loop has a preheader if there is only one edge to the header of the loop
103 /// from outside of the loop. If this is the case, the block branching to the
104 /// header of the loop is the preheader node.
105 ///
106 /// This method returns null if there is no preheader for the loop.
107 ///
108 template<class BlockT, class LoopT>
110  // Keep track of nodes outside the loop branching to the header...
111  BlockT *Out = getLoopPredecessor();
112  if (!Out) return nullptr;
113 
114  // Make sure there is only one exit out of the preheader.
115  typedef GraphTraits<BlockT*> BlockTraits;
116  typename BlockTraits::ChildIteratorType SI = BlockTraits::child_begin(Out);
117  ++SI;
118  if (SI != BlockTraits::child_end(Out))
119  return nullptr; // Multiple exits from the block, must not be a preheader.
120 
121  // The predecessor has exactly one successor, so it is a preheader.
122  return Out;
123 }
124 
125 /// getLoopPredecessor - If the given loop's header has exactly one unique
126 /// predecessor outside the loop, return it. Otherwise return null.
127 /// This is less strict that the loop "preheader" concept, which requires
128 /// the predecessor to have exactly one successor.
129 ///
130 template<class BlockT, class LoopT>
132  // Keep track of nodes outside the loop branching to the header...
133  BlockT *Out = nullptr;
134 
135  // Loop over the predecessors of the header node...
136  BlockT *Header = getHeader();
137  typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
138  for (typename InvBlockTraits::ChildIteratorType PI =
139  InvBlockTraits::child_begin(Header),
140  PE = InvBlockTraits::child_end(Header); PI != PE; ++PI) {
141  typename InvBlockTraits::NodeRef N = *PI;
142  if (!contains(N)) { // If the block is not in the loop...
143  if (Out && Out != N)
144  return nullptr; // Multiple predecessors outside the loop
145  Out = N;
146  }
147  }
148 
149  // Make sure there is only one exit out of the preheader.
150  assert(Out && "Header of loop has no predecessors from outside loop?");
151  return Out;
152 }
153 
154 /// getLoopLatch - If there is a single latch block for this loop, return it.
155 /// A latch block is a block that contains a branch back to the header.
156 template<class BlockT, class LoopT>
158  BlockT *Header = getHeader();
159  typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
160  typename InvBlockTraits::ChildIteratorType PI =
161  InvBlockTraits::child_begin(Header);
162  typename InvBlockTraits::ChildIteratorType PE =
163  InvBlockTraits::child_end(Header);
164  BlockT *Latch = nullptr;
165  for (; PI != PE; ++PI) {
166  typename InvBlockTraits::NodeRef N = *PI;
167  if (contains(N)) {
168  if (Latch) return nullptr;
169  Latch = N;
170  }
171  }
172 
173  return Latch;
174 }
175 
176 //===----------------------------------------------------------------------===//
177 // APIs for updating loop information after changing the CFG
178 //
179 
180 /// addBasicBlockToLoop - This method is used by other analyses to update loop
181 /// information. NewBB is set to be a new member of the current loop.
182 /// Because of this, it is added as a member of all parent loops, and is added
183 /// to the specified LoopInfo object as being in the current basic block. It
184 /// is not valid to replace the loop header with this method.
185 ///
186 template<class BlockT, class LoopT>
189 #ifndef NDEBUG
190  if (!Blocks.empty()) {
191  auto SameHeader = LIB[getHeader()];
192  assert(contains(SameHeader) && getHeader() == SameHeader->getHeader()
193  && "Incorrect LI specified for this loop!");
194  }
195 #endif
196  assert(NewBB && "Cannot add a null basic block to the loop!");
197  assert(!LIB[NewBB] && "BasicBlock already in the loop!");
198 
199  LoopT *L = static_cast<LoopT *>(this);
200 
201  // Add the loop mapping to the LoopInfo object...
202  LIB.BBMap[NewBB] = L;
203 
204  // Add the basic block to this loop and all parent loops...
205  while (L) {
206  L->addBlockEntry(NewBB);
207  L = L->getParentLoop();
208  }
209 }
210 
211 /// replaceChildLoopWith - This is used when splitting loops up. It replaces
212 /// the OldChild entry in our children list with NewChild, and updates the
213 /// parent pointer of OldChild to be null and the NewChild to be this loop.
214 /// This updates the loop depth of the new child.
215 template<class BlockT, class LoopT>
217 replaceChildLoopWith(LoopT *OldChild, LoopT *NewChild) {
218  assert(OldChild->ParentLoop == this && "This loop is already broken!");
219  assert(!NewChild->ParentLoop && "NewChild already has a parent!");
220  typename std::vector<LoopT *>::iterator I = find(SubLoops, OldChild);
221  assert(I != SubLoops.end() && "OldChild not in loop!");
222  *I = NewChild;
223  OldChild->ParentLoop = nullptr;
224  NewChild->ParentLoop = static_cast<LoopT *>(this);
225 }
226 
227 /// verifyLoop - Verify loop structure
228 template<class BlockT, class LoopT>
230 #ifndef NDEBUG
231  assert(!Blocks.empty() && "Loop header is missing");
232 
233  // Setup for using a depth-first iterator to visit every block in the loop.
234  SmallVector<BlockT*, 8> ExitBBs;
235  getExitBlocks(ExitBBs);
237  VisitSet.insert(ExitBBs.begin(), ExitBBs.end());
239  BI = df_ext_begin(getHeader(), VisitSet),
240  BE = df_ext_end(getHeader(), VisitSet);
241 
242  // Keep track of the number of BBs visited.
243  unsigned NumVisited = 0;
244 
245  // Check the individual blocks.
246  for ( ; BI != BE; ++BI) {
247  BlockT *BB = *BI;
248 
251  [&](BlockT *B){return contains(B);}) &&
252  "Loop block has no in-loop successors!");
253 
254  assert(std::any_of(GraphTraits<Inverse<BlockT*> >::child_begin(BB),
255  GraphTraits<Inverse<BlockT*> >::child_end(BB),
256  [&](BlockT *B){return contains(B);}) &&
257  "Loop block has no in-loop predecessors!");
258 
259  SmallVector<BlockT *, 2> OutsideLoopPreds;
260  std::for_each(GraphTraits<Inverse<BlockT*> >::child_begin(BB),
261  GraphTraits<Inverse<BlockT*> >::child_end(BB),
262  [&](BlockT *B){if (!contains(B))
263  OutsideLoopPreds.push_back(B);
264  });
265 
266  if (BB == getHeader()) {
267  assert(!OutsideLoopPreds.empty() && "Loop is unreachable!");
268  } else if (!OutsideLoopPreds.empty()) {
269  // A non-header loop shouldn't be reachable from outside the loop,
270  // though it is permitted if the predecessor is not itself actually
271  // reachable.
272  BlockT *EntryBB = &BB->getParent()->front();
273  for (BlockT *CB : depth_first(EntryBB))
274  for (unsigned i = 0, e = OutsideLoopPreds.size(); i != e; ++i)
275  assert(CB != OutsideLoopPreds[i] &&
276  "Loop has multiple entry points!");
277  }
278  assert(BB != &getHeader()->getParent()->front() &&
279  "Loop contains function entry block!");
280 
281  NumVisited++;
282  }
283 
284  assert(NumVisited == getNumBlocks() && "Unreachable block in loop");
285 
286  // Check the subloops.
287  for (iterator I = begin(), E = end(); I != E; ++I)
288  // Each block in each subloop should be contained within this loop.
289  for (block_iterator BI = (*I)->block_begin(), BE = (*I)->block_end();
290  BI != BE; ++BI) {
291  assert(contains(*BI) &&
292  "Loop does not contain all the blocks of a subloop!");
293  }
294 
295  // Check the parent loop pointer.
296  if (ParentLoop) {
297  assert(is_contained(*ParentLoop, this) &&
298  "Loop is not a subloop of its parent!");
299  }
300 #endif
301 }
302 
303 /// verifyLoop - Verify loop structure of this loop and all nested loops.
304 template<class BlockT, class LoopT>
306  DenseSet<const LoopT*> *Loops) const {
307  Loops->insert(static_cast<const LoopT *>(this));
308  // Verify this loop.
309  verifyLoop();
310  // Verify the subloops.
311  for (iterator I = begin(), E = end(); I != E; ++I)
312  (*I)->verifyLoopNest(Loops);
313 }
314 
315 template<class BlockT, class LoopT>
317  bool Verbose) const {
318  OS.indent(Depth*2) << "Loop at depth " << getLoopDepth()
319  << " containing: ";
320 
321  BlockT *H = getHeader();
322  for (unsigned i = 0; i < getBlocks().size(); ++i) {
323  BlockT *BB = getBlocks()[i];
324  if (!Verbose) {
325  if (i) OS << ",";
326  BB->printAsOperand(OS, false);
327  } else OS << "\n";
328 
329  if (BB == H) OS << "<header>";
330  if (isLoopLatch(BB)) OS << "<latch>";
331  if (isLoopExiting(BB)) OS << "<exiting>";
332  if (Verbose)
333  BB->print(OS);
334  }
335  OS << "\n";
336 
337  for (iterator I = begin(), E = end(); I != E; ++I)
338  (*I)->print(OS, Depth+2);
339 }
340 
341 //===----------------------------------------------------------------------===//
342 /// Stable LoopInfo Analysis - Build a loop tree using stable iterators so the
343 /// result does / not depend on use list (block predecessor) order.
344 ///
345 
346 /// Discover a subloop with the specified backedges such that: All blocks within
347 /// this loop are mapped to this loop or a subloop. And all subloops within this
348 /// loop have their parent loop set to this loop or a subloop.
349 template<class BlockT, class LoopT>
350 static void discoverAndMapSubloop(LoopT *L, ArrayRef<BlockT*> Backedges,
352  const DominatorTreeBase<BlockT> &DomTree) {
353  typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
354 
355  unsigned NumBlocks = 0;
356  unsigned NumSubloops = 0;
357 
358  // Perform a backward CFG traversal using a worklist.
359  std::vector<BlockT *> ReverseCFGWorklist(Backedges.begin(), Backedges.end());
360  while (!ReverseCFGWorklist.empty()) {
361  BlockT *PredBB = ReverseCFGWorklist.back();
362  ReverseCFGWorklist.pop_back();
363 
364  LoopT *Subloop = LI->getLoopFor(PredBB);
365  if (!Subloop) {
366  if (!DomTree.isReachableFromEntry(PredBB))
367  continue;
368 
369  // This is an undiscovered block. Map it to the current loop.
370  LI->changeLoopFor(PredBB, L);
371  ++NumBlocks;
372  if (PredBB == L->getHeader())
373  continue;
374  // Push all block predecessors on the worklist.
375  ReverseCFGWorklist.insert(ReverseCFGWorklist.end(),
376  InvBlockTraits::child_begin(PredBB),
377  InvBlockTraits::child_end(PredBB));
378  }
379  else {
380  // This is a discovered block. Find its outermost discovered loop.
381  while (LoopT *Parent = Subloop->getParentLoop())
382  Subloop = Parent;
383 
384  // If it is already discovered to be a subloop of this loop, continue.
385  if (Subloop == L)
386  continue;
387 
388  // Discover a subloop of this loop.
389  Subloop->setParentLoop(L);
390  ++NumSubloops;
391  NumBlocks += Subloop->getBlocks().capacity();
392  PredBB = Subloop->getHeader();
393  // Continue traversal along predecessors that are not loop-back edges from
394  // within this subloop tree itself. Note that a predecessor may directly
395  // reach another subloop that is not yet discovered to be a subloop of
396  // this loop, which we must traverse.
397  for (typename InvBlockTraits::ChildIteratorType PI =
398  InvBlockTraits::child_begin(PredBB),
399  PE = InvBlockTraits::child_end(PredBB); PI != PE; ++PI) {
400  if (LI->getLoopFor(*PI) != Subloop)
401  ReverseCFGWorklist.push_back(*PI);
402  }
403  }
404  }
405  L->getSubLoopsVector().reserve(NumSubloops);
406  L->reserveBlocks(NumBlocks);
407 }
408 
409 /// Populate all loop data in a stable order during a single forward DFS.
410 template<class BlockT, class LoopT>
413  typedef typename BlockTraits::ChildIteratorType SuccIterTy;
414 
416 public:
418  LI(li) {}
419 
420  void traverse(BlockT *EntryBlock);
421 
422 protected:
423  void insertIntoLoop(BlockT *Block);
424 };
425 
426 /// Top-level driver for the forward DFS within the loop.
427 template<class BlockT, class LoopT>
429  for (BlockT *BB : post_order(EntryBlock))
430  insertIntoLoop(BB);
431 }
432 
433 /// Add a single Block to its ancestor loops in PostOrder. If the block is a
434 /// subloop header, add the subloop to its parent in PostOrder, then reverse the
435 /// Block and Subloop vectors of the now complete subloop to achieve RPO.
436 template<class BlockT, class LoopT>
438  LoopT *Subloop = LI->getLoopFor(Block);
439  if (Subloop && Block == Subloop->getHeader()) {
440  // We reach this point once per subloop after processing all the blocks in
441  // the subloop.
442  if (Subloop->getParentLoop())
443  Subloop->getParentLoop()->getSubLoopsVector().push_back(Subloop);
444  else
445  LI->addTopLevelLoop(Subloop);
446 
447  // For convenience, Blocks and Subloops are inserted in postorder. Reverse
448  // the lists, except for the loop header, which is always at the beginning.
449  Subloop->reverseBlock(1);
450  std::reverse(Subloop->getSubLoopsVector().begin(),
451  Subloop->getSubLoopsVector().end());
452 
453  Subloop = Subloop->getParentLoop();
454  }
455  for (; Subloop; Subloop = Subloop->getParentLoop())
456  Subloop->addBlockEntry(Block);
457 }
458 
459 /// Analyze LoopInfo discovers loops during a postorder DominatorTree traversal
460 /// interleaved with backward CFG traversals within each subloop
461 /// (discoverAndMapSubloop). The backward traversal skips inner subloops, so
462 /// this part of the algorithm is linear in the number of CFG edges. Subloop and
463 /// Block vectors are then populated during a single forward CFG traversal
464 /// (PopulateLoopDFS).
465 ///
466 /// During the two CFG traversals each block is seen three times:
467 /// 1) Discovered and mapped by a reverse CFG traversal.
468 /// 2) Visited during a forward DFS CFG traversal.
469 /// 3) Reverse-inserted in the loop in postorder following forward DFS.
470 ///
471 /// The Block vectors are inclusive, so step 3 requires loop-depth number of
472 /// insertions per block.
473 template<class BlockT, class LoopT>
476 
477  // Postorder traversal of the dominator tree.
478  const DomTreeNodeBase<BlockT> *DomRoot = DomTree.getRootNode();
479  for (auto DomNode : post_order(DomRoot)) {
480 
481  BlockT *Header = DomNode->getBlock();
482  SmallVector<BlockT *, 4> Backedges;
483 
484  // Check each predecessor of the potential loop header.
485  typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
486  for (typename InvBlockTraits::ChildIteratorType PI =
487  InvBlockTraits::child_begin(Header),
488  PE = InvBlockTraits::child_end(Header); PI != PE; ++PI) {
489 
490  BlockT *Backedge = *PI;
491 
492  // If Header dominates predBB, this is a new loop. Collect the backedges.
493  if (DomTree.dominates(Header, Backedge)
494  && DomTree.isReachableFromEntry(Backedge)) {
495  Backedges.push_back(Backedge);
496  }
497  }
498  // Perform a backward CFG traversal to discover and map blocks in this loop.
499  if (!Backedges.empty()) {
500  LoopT *L = new LoopT(Header);
501  discoverAndMapSubloop(L, ArrayRef<BlockT*>(Backedges), this, DomTree);
502  }
503  }
504  // Perform a single forward CFG traversal to populate block and subloop
505  // vectors for all loops.
507  DFS.traverse(DomRoot->getBlock());
508 }
509 
510 // Debugging
511 template<class BlockT, class LoopT>
513  for (unsigned i = 0; i < TopLevelLoops.size(); ++i)
514  TopLevelLoops[i]->print(OS);
515 #if 0
517  E = BBMap.end(); I != E; ++I)
518  OS << "BB '" << I->first->getName() << "' level = "
519  << I->second->getLoopDepth() << "\n";
520 #endif
521 }
522 
523 template <typename T>
524 bool compareVectors(std::vector<T> &BB1, std::vector<T> &BB2) {
525  std::sort(BB1.begin(), BB1.end());
526  std::sort(BB2.begin(), BB2.end());
527  return BB1 == BB2;
528 }
529 
530 template <class BlockT, class LoopT>
531 static void
533  const LoopInfoBase<BlockT, LoopT> &LI,
534  const LoopT &L) {
535  LoopHeaders[L.getHeader()] = &L;
536  for (LoopT *SL : L)
537  addInnerLoopsToHeadersMap(LoopHeaders, LI, *SL);
538 }
539 
540 template <class BlockT, class LoopT>
542  const DominatorTreeBase<BlockT> &DomTree) const {
544  for (iterator I = begin(), E = end(); I != E; ++I) {
545  assert(!(*I)->getParentLoop() && "Top-level loop has a parent!");
546  (*I)->verifyLoopNest(&Loops);
547  }
548 
549  // Verify that blocks are mapped to valid loops.
550 #ifndef NDEBUG
551  for (auto &Entry : BBMap) {
552  const BlockT *BB = Entry.first;
553  LoopT *L = Entry.second;
554  assert(Loops.count(L) && "orphaned loop");
555  assert(L->contains(BB) && "orphaned block");
556  }
557 
558  // Recompute LoopInfo to verify loops structure.
560  OtherLI.analyze(DomTree);
561 
564 
565  for (LoopT *L : *this)
566  addInnerLoopsToHeadersMap(LoopHeaders1, *this, *L);
567  for (LoopT *L : OtherLI)
568  addInnerLoopsToHeadersMap(LoopHeaders2, OtherLI, *L);
569  assert(LoopHeaders1.size() == LoopHeaders2.size() &&
570  "LoopInfo is incorrect.");
571 
572  auto compareLoops = [&](const LoopT *L1, const LoopT *L2) {
573  BlockT *H1 = L1->getHeader();
574  BlockT *H2 = L2->getHeader();
575  if (H1 != H2)
576  return false;
577  std::vector<BlockT *> BB1 = L1->getBlocks();
578  std::vector<BlockT *> BB2 = L2->getBlocks();
579  if (!compareVectors(BB1, BB2))
580  return false;
581 
582  std::vector<BlockT *> SubLoopHeaders1;
583  std::vector<BlockT *> SubLoopHeaders2;
584  for (LoopT *L : *L1)
585  SubLoopHeaders1.push_back(L->getHeader());
586  for (LoopT *L : *L2)
587  SubLoopHeaders2.push_back(L->getHeader());
588 
589  if (!compareVectors(SubLoopHeaders1, SubLoopHeaders2))
590  return false;
591  return true;
592  };
593 
594  for (auto &I : LoopHeaders1) {
595  BlockT *H = I.first;
596  bool LoopsMatch = compareLoops(LoopHeaders1[H], LoopHeaders2[H]);
597  assert(LoopsMatch && "LoopInfo is incorrect.");
598  }
599 #endif
600 }
601 
602 } // End llvm namespace
603 
604 #endif
MachineLoop * L
const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:241
size_t i
bool compareVectors(std::vector< T > &BB1, std::vector< T > &BB2)
Definition: LoopInfoImpl.h:524
Implements a dense probed hash-table based set.
Definition: DenseSet.h:202
iterator end() const
Definition: ArrayRef.h:130
raw_ostream & indent(unsigned NumSpaces)
indent - Insert 'NumSpaces' spaces.
void replaceChildLoopWith(LoopT *OldChild, LoopT *NewChild)
This is used when splitting loops up.
Definition: LoopInfoImpl.h:217
const_iterator begin(StringRef path)
Get begin iterator over path.
Definition: Path.cpp:233
void insertIntoLoop(BlockT *Block)
Add a single Block to its ancestor loops in PostOrder.
Definition: LoopInfoImpl.h:437
void changeLoopFor(BlockT *BB, LoopT *L)
Change the top-level loop that contains BB to the specified loop.
Definition: LoopInfo.h:609
LoopT * getLoopFor(const BlockT *BB) const
Return the inner most loop that BB lives in.
Definition: LoopInfo.h:575
BlockT * getExitBlock() const
If getExitBlocks would return exactly one block, return that block.
Definition: LoopInfoImpl.h:79
return AArch64::GPR64RegClass contains(Reg)
std::vector< LoopT * >::const_iterator iterator
iterator/begin/end - The interface to the top-level loops in the current function.
Definition: LoopInfo.h:564
BlockT * getLoopLatch() const
If there is a single latch block for this loop, return it.
Definition: LoopInfoImpl.h:157
void getExitEdges(SmallVectorImpl< Edge > &ExitEdges) const
Return all pairs of (inside_block,outside_block).
Definition: LoopInfoImpl.h:90
Hexagon Hardware Loops
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:32
void getExitingBlocks(SmallVectorImpl< BlockT * > &ExitingBlocks) const
Return all blocks inside the loop that have successors outside of the loop.
Definition: LoopInfoImpl.h:36
DomTreeNodeBase< NodeT > * getRootNode()
getRootNode - This returns the entry node for the CFG of the function.
static void discoverAndMapSubloop(LoopT *L, ArrayRef< BlockT * > Backedges, LoopInfoBase< BlockT, LoopT > *LI, const DominatorTreeBase< BlockT > &DomTree)
Stable LoopInfo Analysis - Build a loop tree using stable iterators so the result does / not depend o...
Definition: LoopInfoImpl.h:350
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:60
void getExitBlocks(SmallVectorImpl< BlockT * > &ExitBlocks) const
Return all of the successor blocks of this loop.
Definition: LoopInfoImpl.h:65
auto reverse(ContainerTy &&C, typename std::enable_if< has_rbegin< ContainerTy >::value >::type *=nullptr) -> decltype(make_range(C.rbegin(), C.rend()))
Definition: STLExtras.h:241
void addBasicBlockToLoop(BlockT *NewBB, LoopInfoBase< BlockT, LoopT > &LI)
This method is used by other analyses to update loop information.
Definition: LoopInfoImpl.h:188
void traverse(BlockT *EntryBlock)
Top-level driver for the forward DFS within the loop.
Definition: LoopInfoImpl.h:428
Base class for the actual dominator tree node.
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:33
static GCRegistry::Add< OcamlGC > B("ocaml","ocaml 3.10-compatible GC")
NodeT * getBlock() const
static GCRegistry::Add< CoreCLRGC > E("coreclr","CoreCLR-compatible GC")
void verifyLoop() const
Verify loop structure.
Definition: LoopInfoImpl.h:229
Core dominator tree base class.
Definition: LoopInfo.h:59
PopulateLoopsDFS(LoopInfoBase< BlockT, LoopT > *li)
Definition: LoopInfoImpl.h:417
BlockT * getLoopPreheader() const
If there is a preheader for this loop, return it.
Definition: LoopInfoImpl.h:109
bool isReachableFromEntry(const NodeT *A) const
isReachableFromEntry - Return true if A is dominated by the entry block of the function containing it...
bool dominates(const DomTreeNodeBase< NodeT > *A, const DomTreeNodeBase< NodeT > *B) const
dominates - Returns true iff A dominates B.
df_ext_iterator< T, SetTy > df_ext_end(const T &G, SetTy &S)
#define H(x, y, z)
Definition: MD5.cpp:53
void analyze(const DominatorTreeBase< BlockT > &DomTree)
Create the loop forest using a stable algorithm.
Definition: LoopInfoImpl.h:475
df_ext_iterator< T, SetTy > df_ext_begin(const T &G, SetTy &S)
bool any_of(R &&Range, UnaryPredicate P)
Provide wrappers to std::any_of which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:743
iterator begin() const
Definition: ArrayRef.h:129
BlockT * getExitingBlock() const
If getExitingBlocks would return exactly one block, return that block.
Definition: LoopInfoImpl.h:52
iterator_range< po_iterator< T > > post_order(const T &G)
void addBlockEntry(BlockT *BB)
This adds a basic block directly to the basic block list.
Definition: LoopInfo.h:299
static void DFS(BasicBlock *Root, SetVector< BasicBlock * > &Set)
std::pair< const BlockT *, const BlockT * > Edge
Edge type.
Definition: LoopInfo.h:225
auto find(R &&Range, const T &Val) -> decltype(std::begin(Range))
Provide wrappers to std::find which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:757
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:843
std::pair< iterator, bool > insert(NodeRef N)
std::vector< BlockT * >::const_iterator block_iterator
Definition: LoopInfo.h:140
void verifyLoopNest(DenseSet< const LoopT * > *Loops) const
Verify loop structure of this loop and all nested loops.
Definition: LoopInfoImpl.h:305
size_type count(const ValueT &V) const
Return 1 if the specified key is in the set, 0 otherwise.
Definition: DenseSet.h:81
#define I(x, y, z)
Definition: MD5.cpp:54
#define N
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:135
BlockT * getLoopPredecessor() const
If the given loop's header has exactly one unique predecessor outside the loop, return it...
Definition: LoopInfoImpl.h:131
static void addInnerLoopsToHeadersMap(DenseMap< BlockT *, const LoopT * > &LoopHeaders, const LoopInfoBase< BlockT, LoopT > &LI, const LoopT &L)
Definition: LoopInfoImpl.h:532
iterator_range< df_iterator< T > > depth_first(const T &G)
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
static const Function * getParent(const Value *V)
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:44
void print(raw_ostream &OS, unsigned Depth=0, bool Verbose=false) const
Print loop with all the BBs inside it.
Definition: LoopInfoImpl.h:316
ppc ctr loops verify
std::vector< LoopT * >::const_iterator iterator
Definition: LoopInfo.h:129
Populate all loop data in a stable order during a single forward DFS.
Definition: LoopInfoImpl.h:411
bool is_contained(R &&Range, const E &Element)
Wrapper function around std::find to detect if an element exists in a container.
Definition: STLExtras.h:783