LLVM  6.0.0svn
LiveInterval.cpp
Go to the documentation of this file.
1 //===- LiveInterval.cpp - Live Interval Representation --------------------===//
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 LiveRange and LiveInterval classes. Given some
11 // numbering of each the machine instructions an interval [i, j) is said to be a
12 // live range for register v if there is no instruction with number j' >= j
13 // such that v is live at j' and there is no instruction with number i' < i such
14 // that v is live at i'. In this implementation ranges can have holes,
15 // i.e. a range might look like [1,20), [50,65), [1000,1001). Each
16 // individual segment is represented as an instance of LiveRange::Segment,
17 // and the whole range is represented as an instance of LiveRange.
18 //
19 //===----------------------------------------------------------------------===//
20 
22 #include "LiveRangeUtils.h"
23 #include "RegisterCoalescer.h"
24 #include "llvm/ADT/ArrayRef.h"
25 #include "llvm/ADT/STLExtras.h"
26 #include "llvm/ADT/SmallPtrSet.h"
27 #include "llvm/ADT/SmallVector.h"
36 #include "llvm/MC/LaneBitmask.h"
37 #include "llvm/Support/Compiler.h"
38 #include "llvm/Support/Debug.h"
40 #include <algorithm>
41 #include <cassert>
42 #include <cstddef>
43 #include <iterator>
44 #include <utility>
45 
46 using namespace llvm;
47 
48 namespace {
49 
50 //===----------------------------------------------------------------------===//
51 // Implementation of various methods necessary for calculation of live ranges.
52 // The implementation of the methods abstracts from the concrete type of the
53 // segment collection.
54 //
55 // Implementation of the class follows the Template design pattern. The base
56 // class contains generic algorithms that call collection-specific methods,
57 // which are provided in concrete subclasses. In order to avoid virtual calls
58 // these methods are provided by means of C++ template instantiation.
59 // The base class calls the methods of the subclass through method impl(),
60 // which casts 'this' pointer to the type of the subclass.
61 //
62 //===----------------------------------------------------------------------===//
63 
64 template <typename ImplT, typename IteratorT, typename CollectionT>
65 class CalcLiveRangeUtilBase {
66 protected:
67  LiveRange *LR;
68 
69 protected:
70  CalcLiveRangeUtilBase(LiveRange *LR) : LR(LR) {}
71 
72 public:
73  using Segment = LiveRange::Segment;
74  using iterator = IteratorT;
75 
76  /// A counterpart of LiveRange::createDeadDef: Make sure the range has a
77  /// value defined at @p Def.
78  /// If @p ForVNI is null, and there is no value defined at @p Def, a new
79  /// value will be allocated using @p VNInfoAllocator.
80  /// If @p ForVNI is null, the return value is the value defined at @p Def,
81  /// either a pre-existing one, or the one newly created.
82  /// If @p ForVNI is not null, then @p Def should be the location where
83  /// @p ForVNI is defined. If the range does not have a value defined at
84  /// @p Def, the value @p ForVNI will be used instead of allocating a new
85  /// one. If the range already has a value defined at @p Def, it must be
86  /// same as @p ForVNI. In either case, @p ForVNI will be the return value.
88  VNInfo *ForVNI) {
89  assert(!Def.isDead() && "Cannot define a value at the dead slot");
90  assert((!ForVNI || ForVNI->def == Def) &&
91  "If ForVNI is specified, it must match Def");
92  iterator I = impl().find(Def);
93  if (I == segments().end()) {
94  VNInfo *VNI = ForVNI ? ForVNI : LR->getNextValue(Def, *VNInfoAllocator);
95  impl().insertAtEnd(Segment(Def, Def.getDeadSlot(), VNI));
96  return VNI;
97  }
98 
99  Segment *S = segmentAt(I);
100  if (SlotIndex::isSameInstr(Def, S->start)) {
101  assert((!ForVNI || ForVNI == S->valno) && "Value number mismatch");
102  assert(S->valno->def == S->start && "Inconsistent existing value def");
103 
104  // It is possible to have both normal and early-clobber defs of the same
105  // register on an instruction. It doesn't make a lot of sense, but it is
106  // possible to specify in inline assembly.
107  //
108  // Just convert everything to early-clobber.
109  Def = std::min(Def, S->start);
110  if (Def != S->start)
111  S->start = S->valno->def = Def;
112  return S->valno;
113  }
114  assert(SlotIndex::isEarlierInstr(Def, S->start) && "Already live at def");
115  VNInfo *VNI = ForVNI ? ForVNI : LR->getNextValue(Def, *VNInfoAllocator);
116  segments().insert(I, Segment(Def, Def.getDeadSlot(), VNI));
117  return VNI;
118  }
119 
120  VNInfo *extendInBlock(SlotIndex StartIdx, SlotIndex Use) {
121  if (segments().empty())
122  return nullptr;
123  iterator I =
124  impl().findInsertPos(Segment(Use.getPrevSlot(), Use, nullptr));
125  if (I == segments().begin())
126  return nullptr;
127  --I;
128  if (I->end <= StartIdx)
129  return nullptr;
130  if (I->end < Use)
131  extendSegmentEndTo(I, Use);
132  return I->valno;
133  }
134 
135  std::pair<VNInfo*,bool> extendInBlock(ArrayRef<SlotIndex> Undefs,
136  SlotIndex StartIdx, SlotIndex Use) {
137  if (segments().empty())
138  return std::make_pair(nullptr, false);
139  SlotIndex BeforeUse = Use.getPrevSlot();
140  iterator I = impl().findInsertPos(Segment(BeforeUse, Use, nullptr));
141  if (I == segments().begin())
142  return std::make_pair(nullptr, LR->isUndefIn(Undefs, StartIdx, BeforeUse));
143  --I;
144  if (I->end <= StartIdx)
145  return std::make_pair(nullptr, LR->isUndefIn(Undefs, StartIdx, BeforeUse));
146  if (I->end < Use) {
147  if (LR->isUndefIn(Undefs, I->end, BeforeUse))
148  return std::make_pair(nullptr, true);
149  extendSegmentEndTo(I, Use);
150  }
151  return std::make_pair(I->valno, false);
152  }
153 
154  /// This method is used when we want to extend the segment specified
155  /// by I to end at the specified endpoint. To do this, we should
156  /// merge and eliminate all segments that this will overlap
157  /// with. The iterator is not invalidated.
158  void extendSegmentEndTo(iterator I, SlotIndex NewEnd) {
159  assert(I != segments().end() && "Not a valid segment!");
160  Segment *S = segmentAt(I);
161  VNInfo *ValNo = I->valno;
162 
163  // Search for the first segment that we can't merge with.
164  iterator MergeTo = std::next(I);
165  for (; MergeTo != segments().end() && NewEnd >= MergeTo->end; ++MergeTo)
166  assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
167 
168  // If NewEnd was in the middle of a segment, make sure to get its endpoint.
169  S->end = std::max(NewEnd, std::prev(MergeTo)->end);
170 
171  // If the newly formed segment now touches the segment after it and if they
172  // have the same value number, merge the two segments into one segment.
173  if (MergeTo != segments().end() && MergeTo->start <= I->end &&
174  MergeTo->valno == ValNo) {
175  S->end = MergeTo->end;
176  ++MergeTo;
177  }
178 
179  // Erase any dead segments.
180  segments().erase(std::next(I), MergeTo);
181  }
182 
183  /// This method is used when we want to extend the segment specified
184  /// by I to start at the specified endpoint. To do this, we should
185  /// merge and eliminate all segments that this will overlap with.
186  iterator extendSegmentStartTo(iterator I, SlotIndex NewStart) {
187  assert(I != segments().end() && "Not a valid segment!");
188  Segment *S = segmentAt(I);
189  VNInfo *ValNo = I->valno;
190 
191  // Search for the first segment that we can't merge with.
192  iterator MergeTo = I;
193  do {
194  if (MergeTo == segments().begin()) {
195  S->start = NewStart;
196  segments().erase(MergeTo, I);
197  return I;
198  }
199  assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
200  --MergeTo;
201  } while (NewStart <= MergeTo->start);
202 
203  // If we start in the middle of another segment, just delete a range and
204  // extend that segment.
205  if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) {
206  segmentAt(MergeTo)->end = S->end;
207  } else {
208  // Otherwise, extend the segment right after.
209  ++MergeTo;
210  Segment *MergeToSeg = segmentAt(MergeTo);
211  MergeToSeg->start = NewStart;
212  MergeToSeg->end = S->end;
213  }
214 
215  segments().erase(std::next(MergeTo), std::next(I));
216  return MergeTo;
217  }
218 
219  iterator addSegment(Segment S) {
220  SlotIndex Start = S.start, End = S.end;
221  iterator I = impl().findInsertPos(S);
222 
223  // If the inserted segment starts in the middle or right at the end of
224  // another segment, just extend that segment to contain the segment of S.
225  if (I != segments().begin()) {
226  iterator B = std::prev(I);
227  if (S.valno == B->valno) {
228  if (B->start <= Start && B->end >= Start) {
229  extendSegmentEndTo(B, End);
230  return B;
231  }
232  } else {
233  // Check to make sure that we are not overlapping two live segments with
234  // different valno's.
235  assert(B->end <= Start &&
236  "Cannot overlap two segments with differing ValID's"
237  " (did you def the same reg twice in a MachineInstr?)");
238  }
239  }
240 
241  // Otherwise, if this segment ends in the middle of, or right next
242  // to, another segment, merge it into that segment.
243  if (I != segments().end()) {
244  if (S.valno == I->valno) {
245  if (I->start <= End) {
246  I = extendSegmentStartTo(I, Start);
247 
248  // If S is a complete superset of a segment, we may need to grow its
249  // endpoint as well.
250  if (End > I->end)
251  extendSegmentEndTo(I, End);
252  return I;
253  }
254  } else {
255  // Check to make sure that we are not overlapping two live segments with
256  // different valno's.
257  assert(I->start >= End &&
258  "Cannot overlap two segments with differing ValID's");
259  }
260  }
261 
262  // Otherwise, this is just a new segment that doesn't interact with
263  // anything.
264  // Insert it.
265  return segments().insert(I, S);
266  }
267 
268 private:
269  ImplT &impl() { return *static_cast<ImplT *>(this); }
270 
271  CollectionT &segments() { return impl().segmentsColl(); }
272 
273  Segment *segmentAt(iterator I) { return const_cast<Segment *>(&(*I)); }
274 };
275 
276 //===----------------------------------------------------------------------===//
277 // Instantiation of the methods for calculation of live ranges
278 // based on a segment vector.
279 //===----------------------------------------------------------------------===//
280 
281 class CalcLiveRangeUtilVector;
282 using CalcLiveRangeUtilVectorBase =
283  CalcLiveRangeUtilBase<CalcLiveRangeUtilVector, LiveRange::iterator,
285 
286 class CalcLiveRangeUtilVector : public CalcLiveRangeUtilVectorBase {
287 public:
288  CalcLiveRangeUtilVector(LiveRange *LR) : CalcLiveRangeUtilVectorBase(LR) {}
289 
290 private:
291  friend CalcLiveRangeUtilVectorBase;
292 
293  LiveRange::Segments &segmentsColl() { return LR->segments; }
294 
295  void insertAtEnd(const Segment &S) { LR->segments.push_back(S); }
296 
297  iterator find(SlotIndex Pos) { return LR->find(Pos); }
298 
299  iterator findInsertPos(Segment S) {
300  return std::upper_bound(LR->begin(), LR->end(), S.start);
301  }
302 };
303 
304 //===----------------------------------------------------------------------===//
305 // Instantiation of the methods for calculation of live ranges
306 // based on a segment set.
307 //===----------------------------------------------------------------------===//
308 
309 class CalcLiveRangeUtilSet;
310 using CalcLiveRangeUtilSetBase =
311  CalcLiveRangeUtilBase<CalcLiveRangeUtilSet, LiveRange::SegmentSet::iterator,
313 
314 class CalcLiveRangeUtilSet : public CalcLiveRangeUtilSetBase {
315 public:
316  CalcLiveRangeUtilSet(LiveRange *LR) : CalcLiveRangeUtilSetBase(LR) {}
317 
318 private:
319  friend CalcLiveRangeUtilSetBase;
320 
321  LiveRange::SegmentSet &segmentsColl() { return *LR->segmentSet; }
322 
323  void insertAtEnd(const Segment &S) {
324  LR->segmentSet->insert(LR->segmentSet->end(), S);
325  }
326 
327  iterator find(SlotIndex Pos) {
328  iterator I =
329  LR->segmentSet->upper_bound(Segment(Pos, Pos.getNextSlot(), nullptr));
330  if (I == LR->segmentSet->begin())
331  return I;
332  iterator PrevI = std::prev(I);
333  if (Pos < (*PrevI).end)
334  return PrevI;
335  return I;
336  }
337 
338  iterator findInsertPos(Segment S) {
339  iterator I = LR->segmentSet->upper_bound(S);
340  if (I != LR->segmentSet->end() && !(S.start < *I))
341  ++I;
342  return I;
343  }
344 };
345 
346 } // end anonymous namespace
347 
348 //===----------------------------------------------------------------------===//
349 // LiveRange methods
350 //===----------------------------------------------------------------------===//
351 
352 LiveRange::iterator LiveRange::find(SlotIndex Pos) {
353  // This algorithm is basically std::upper_bound.
354  // Unfortunately, std::upper_bound cannot be used with mixed types until we
355  // adopt C++0x. Many libraries can do it, but not all.
356  if (empty() || Pos >= endIndex())
357  return end();
358  iterator I = begin();
359  size_t Len = size();
360  do {
361  size_t Mid = Len >> 1;
362  if (Pos < I[Mid].end) {
363  Len = Mid;
364  } else {
365  I += Mid + 1;
366  Len -= Mid + 1;
367  }
368  } while (Len);
369  return I;
370 }
371 
373  // Use the segment set, if it is available.
374  if (segmentSet != nullptr)
375  return CalcLiveRangeUtilSet(this).createDeadDef(Def, &VNIAlloc, nullptr);
376  // Otherwise use the segment vector.
377  return CalcLiveRangeUtilVector(this).createDeadDef(Def, &VNIAlloc, nullptr);
378 }
379 
381  // Use the segment set, if it is available.
382  if (segmentSet != nullptr)
383  return CalcLiveRangeUtilSet(this).createDeadDef(VNI->def, nullptr, VNI);
384  // Otherwise use the segment vector.
385  return CalcLiveRangeUtilVector(this).createDeadDef(VNI->def, nullptr, VNI);
386 }
387 
388 // overlaps - Return true if the intersection of the two live ranges is
389 // not empty.
390 //
391 // An example for overlaps():
392 //
393 // 0: A = ...
394 // 4: B = ...
395 // 8: C = A + B ;; last use of A
396 //
397 // The live ranges should look like:
398 //
399 // A = [3, 11)
400 // B = [7, x)
401 // C = [11, y)
402 //
403 // A->overlaps(C) should return false since we want to be able to join
404 // A and C.
405 //
407  const_iterator StartPos) const {
408  assert(!empty() && "empty range");
409  const_iterator i = begin();
410  const_iterator ie = end();
411  const_iterator j = StartPos;
412  const_iterator je = other.end();
413 
414  assert((StartPos->start <= i->start || StartPos == other.begin()) &&
415  StartPos != other.end() && "Bogus start position hint!");
416 
417  if (i->start < j->start) {
418  i = std::upper_bound(i, ie, j->start);
419  if (i != begin()) --i;
420  } else if (j->start < i->start) {
421  ++StartPos;
422  if (StartPos != other.end() && StartPos->start <= i->start) {
423  assert(StartPos < other.end() && i < end());
424  j = std::upper_bound(j, je, i->start);
425  if (j != other.begin()) --j;
426  }
427  } else {
428  return true;
429  }
430 
431  if (j == je) return false;
432 
433  while (i != ie) {
434  if (i->start > j->start) {
435  std::swap(i, j);
436  std::swap(ie, je);
437  }
438 
439  if (i->end > j->start)
440  return true;
441  ++i;
442  }
443 
444  return false;
445 }
446 
447 bool LiveRange::overlaps(const LiveRange &Other, const CoalescerPair &CP,
448  const SlotIndexes &Indexes) const {
449  assert(!empty() && "empty range");
450  if (Other.empty())
451  return false;
452 
453  // Use binary searches to find initial positions.
454  const_iterator I = find(Other.beginIndex());
455  const_iterator IE = end();
456  if (I == IE)
457  return false;
458  const_iterator J = Other.find(I->start);
459  const_iterator JE = Other.end();
460  if (J == JE)
461  return false;
462 
463  while (true) {
464  // J has just been advanced to satisfy:
465  assert(J->end >= I->start);
466  // Check for an overlap.
467  if (J->start < I->end) {
468  // I and J are overlapping. Find the later start.
469  SlotIndex Def = std::max(I->start, J->start);
470  // Allow the overlap if Def is a coalescable copy.
471  if (Def.isBlock() ||
472  !CP.isCoalescable(Indexes.getInstructionFromIndex(Def)))
473  return true;
474  }
475  // Advance the iterator that ends first to check for more overlaps.
476  if (J->end > I->end) {
477  std::swap(I, J);
478  std::swap(IE, JE);
479  }
480  // Advance J until J->end >= I->start.
481  do
482  if (++J == JE)
483  return false;
484  while (J->end < I->start);
485  }
486 }
487 
488 /// overlaps - Return true if the live range overlaps an interval specified
489 /// by [Start, End).
491  assert(Start < End && "Invalid range");
492  const_iterator I = std::lower_bound(begin(), end(), End);
493  return I != begin() && (--I)->end > Start;
494 }
495 
496 bool LiveRange::covers(const LiveRange &Other) const {
497  if (empty())
498  return Other.empty();
499 
500  const_iterator I = begin();
501  for (const Segment &O : Other.segments) {
502  I = advanceTo(I, O.start);
503  if (I == end() || I->start > O.start)
504  return false;
505 
506  // Check adjacent live segments and see if we can get behind O.end.
507  while (I->end < O.end) {
508  const_iterator Last = I;
509  // Get next segment and abort if it was not adjacent.
510  ++I;
511  if (I == end() || Last->end != I->start)
512  return false;
513  }
514  }
515  return true;
516 }
517 
518 /// ValNo is dead, remove it. If it is the largest value number, just nuke it
519 /// (and any other deleted values neighboring it), otherwise mark it as ~1U so
520 /// it can be nuked later.
521 void LiveRange::markValNoForDeletion(VNInfo *ValNo) {
522  if (ValNo->id == getNumValNums()-1) {
523  do {
524  valnos.pop_back();
525  } while (!valnos.empty() && valnos.back()->isUnused());
526  } else {
527  ValNo->markUnused();
528  }
529 }
530 
531 /// RenumberValues - Renumber all values in order of appearance and delete the
532 /// remaining unused values.
535  valnos.clear();
536  for (const Segment &S : segments) {
537  VNInfo *VNI = S.valno;
538  if (!Seen.insert(VNI).second)
539  continue;
540  assert(!VNI->isUnused() && "Unused valno used by live segment");
541  VNI->id = (unsigned)valnos.size();
542  valnos.push_back(VNI);
543  }
544 }
545 
546 void LiveRange::addSegmentToSet(Segment S) {
547  CalcLiveRangeUtilSet(this).addSegment(S);
548 }
549 
550 LiveRange::iterator LiveRange::addSegment(Segment S) {
551  // Use the segment set, if it is available.
552  if (segmentSet != nullptr) {
553  addSegmentToSet(S);
554  return end();
555  }
556  // Otherwise use the segment vector.
557  return CalcLiveRangeUtilVector(this).addSegment(S);
558 }
559 
560 void LiveRange::append(const Segment S) {
561  // Check that the segment belongs to the back of the list.
562  assert(segments.empty() || segments.back().end <= S.start);
563  segments.push_back(S);
564 }
565 
566 std::pair<VNInfo*,bool> LiveRange::extendInBlock(ArrayRef<SlotIndex> Undefs,
567  SlotIndex StartIdx, SlotIndex Kill) {
568  // Use the segment set, if it is available.
569  if (segmentSet != nullptr)
570  return CalcLiveRangeUtilSet(this).extendInBlock(Undefs, StartIdx, Kill);
571  // Otherwise use the segment vector.
572  return CalcLiveRangeUtilVector(this).extendInBlock(Undefs, StartIdx, Kill);
573 }
574 
576  // Use the segment set, if it is available.
577  if (segmentSet != nullptr)
578  return CalcLiveRangeUtilSet(this).extendInBlock(StartIdx, Kill);
579  // Otherwise use the segment vector.
580  return CalcLiveRangeUtilVector(this).extendInBlock(StartIdx, Kill);
581 }
582 
583 /// Remove the specified segment from this range. Note that the segment must
584 /// be in a single Segment in its entirety.
586  bool RemoveDeadValNo) {
587  // Find the Segment containing this span.
588  iterator I = find(Start);
589  assert(I != end() && "Segment is not in range!");
590  assert(I->containsInterval(Start, End)
591  && "Segment is not entirely in range!");
592 
593  // If the span we are removing is at the start of the Segment, adjust it.
594  VNInfo *ValNo = I->valno;
595  if (I->start == Start) {
596  if (I->end == End) {
597  if (RemoveDeadValNo) {
598  // Check if val# is dead.
599  bool isDead = true;
600  for (const_iterator II = begin(), EE = end(); II != EE; ++II)
601  if (II != I && II->valno == ValNo) {
602  isDead = false;
603  break;
604  }
605  if (isDead) {
606  // Now that ValNo is dead, remove it.
607  markValNoForDeletion(ValNo);
608  }
609  }
610 
611  segments.erase(I); // Removed the whole Segment.
612  } else
613  I->start = End;
614  return;
615  }
616 
617  // Otherwise if the span we are removing is at the end of the Segment,
618  // adjust the other way.
619  if (I->end == End) {
620  I->end = Start;
621  return;
622  }
623 
624  // Otherwise, we are splitting the Segment into two pieces.
625  SlotIndex OldEnd = I->end;
626  I->end = Start; // Trim the old segment.
627 
628  // Insert the new one.
629  segments.insert(std::next(I), Segment(End, OldEnd, ValNo));
630 }
631 
632 /// removeValNo - Remove all the segments defined by the specified value#.
633 /// Also remove the value# from value# list.
635  if (empty()) return;
636  segments.erase(remove_if(*this, [ValNo](const Segment &S) {
637  return S.valno == ValNo;
638  }), end());
639  // Now that ValNo is dead, remove it.
640  markValNoForDeletion(ValNo);
641 }
642 
644  const int *LHSValNoAssignments,
645  const int *RHSValNoAssignments,
646  SmallVectorImpl<VNInfo *> &NewVNInfo) {
647  verify();
648 
649  // Determine if any of our values are mapped. This is uncommon, so we want
650  // to avoid the range scan if not.
651  bool MustMapCurValNos = false;
652  unsigned NumVals = getNumValNums();
653  unsigned NumNewVals = NewVNInfo.size();
654  for (unsigned i = 0; i != NumVals; ++i) {
655  unsigned LHSValID = LHSValNoAssignments[i];
656  if (i != LHSValID ||
657  (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) {
658  MustMapCurValNos = true;
659  break;
660  }
661  }
662 
663  // If we have to apply a mapping to our base range assignment, rewrite it now.
664  if (MustMapCurValNos && !empty()) {
665  // Map the first live range.
666 
667  iterator OutIt = begin();
668  OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]];
669  for (iterator I = std::next(OutIt), E = end(); I != E; ++I) {
670  VNInfo* nextValNo = NewVNInfo[LHSValNoAssignments[I->valno->id]];
671  assert(nextValNo && "Huh?");
672 
673  // If this live range has the same value # as its immediate predecessor,
674  // and if they are neighbors, remove one Segment. This happens when we
675  // have [0,4:0)[4,7:1) and map 0/1 onto the same value #.
676  if (OutIt->valno == nextValNo && OutIt->end == I->start) {
677  OutIt->end = I->end;
678  } else {
679  // Didn't merge. Move OutIt to the next segment,
680  ++OutIt;
681  OutIt->valno = nextValNo;
682  if (OutIt != I) {
683  OutIt->start = I->start;
684  OutIt->end = I->end;
685  }
686  }
687  }
688  // If we merge some segments, chop off the end.
689  ++OutIt;
690  segments.erase(OutIt, end());
691  }
692 
693  // Rewrite Other values before changing the VNInfo ids.
694  // This can leave Other in an invalid state because we're not coalescing
695  // touching segments that now have identical values. That's OK since Other is
696  // not supposed to be valid after calling join();
697  for (Segment &S : Other.segments)
698  S.valno = NewVNInfo[RHSValNoAssignments[S.valno->id]];
699 
700  // Update val# info. Renumber them and make sure they all belong to this
701  // LiveRange now. Also remove dead val#'s.
702  unsigned NumValNos = 0;
703  for (unsigned i = 0; i < NumNewVals; ++i) {
704  VNInfo *VNI = NewVNInfo[i];
705  if (VNI) {
706  if (NumValNos >= NumVals)
707  valnos.push_back(VNI);
708  else
709  valnos[NumValNos] = VNI;
710  VNI->id = NumValNos++; // Renumber val#.
711  }
712  }
713  if (NumNewVals < NumVals)
714  valnos.resize(NumNewVals); // shrinkify
715 
716  // Okay, now insert the RHS live segments into the LHS.
717  LiveRangeUpdater Updater(this);
718  for (Segment &S : Other.segments)
719  Updater.add(S);
720 }
721 
722 /// Merge all of the segments in RHS into this live range as the specified
723 /// value number. The segments in RHS are allowed to overlap with segments in
724 /// the current range, but only if the overlapping segments have the
725 /// specified value number.
727  VNInfo *LHSValNo) {
728  LiveRangeUpdater Updater(this);
729  for (const Segment &S : RHS.segments)
730  Updater.add(S.start, S.end, LHSValNo);
731 }
732 
733 /// MergeValueInAsValue - Merge all of the live segments of a specific val#
734 /// in RHS into this live range as the specified value number.
735 /// The segments in RHS are allowed to overlap with segments in the
736 /// current range, it will replace the value numbers of the overlaped
737 /// segments with the specified value number.
739  const VNInfo *RHSValNo,
740  VNInfo *LHSValNo) {
741  LiveRangeUpdater Updater(this);
742  for (const Segment &S : RHS.segments)
743  if (S.valno == RHSValNo)
744  Updater.add(S.start, S.end, LHSValNo);
745 }
746 
747 /// MergeValueNumberInto - This method is called when two value nubmers
748 /// are found to be equivalent. This eliminates V1, replacing all
749 /// segments with the V1 value number with the V2 value number. This can
750 /// cause merging of V1/V2 values numbers and compaction of the value space.
752  assert(V1 != V2 && "Identical value#'s are always equivalent!");
753 
754  // This code actually merges the (numerically) larger value number into the
755  // smaller value number, which is likely to allow us to compactify the value
756  // space. The only thing we have to be careful of is to preserve the
757  // instruction that defines the result value.
758 
759  // Make sure V2 is smaller than V1.
760  if (V1->id < V2->id) {
761  V1->copyFrom(*V2);
762  std::swap(V1, V2);
763  }
764 
765  // Merge V1 segments into V2.
766  for (iterator I = begin(); I != end(); ) {
767  iterator S = I++;
768  if (S->valno != V1) continue; // Not a V1 Segment.
769 
770  // Okay, we found a V1 live range. If it had a previous, touching, V2 live
771  // range, extend it.
772  if (S != begin()) {
773  iterator Prev = S-1;
774  if (Prev->valno == V2 && Prev->end == S->start) {
775  Prev->end = S->end;
776 
777  // Erase this live-range.
778  segments.erase(S);
779  I = Prev+1;
780  S = Prev;
781  }
782  }
783 
784  // Okay, now we have a V1 or V2 live range that is maximally merged forward.
785  // Ensure that it is a V2 live-range.
786  S->valno = V2;
787 
788  // If we can merge it into later V2 segments, do so now. We ignore any
789  // following V1 segments, as they will be merged in subsequent iterations
790  // of the loop.
791  if (I != end()) {
792  if (I->start == S->end && I->valno == V2) {
793  S->end = I->end;
794  segments.erase(I);
795  I = S+1;
796  }
797  }
798  }
799 
800  // Now that V1 is dead, remove it.
801  markValNoForDeletion(V1);
802 
803  return V2;
804 }
805 
807  assert(segmentSet != nullptr && "segment set must have been created");
808  assert(
809  segments.empty() &&
810  "segment set can be used only initially before switching to the array");
811  segments.append(segmentSet->begin(), segmentSet->end());
812  segmentSet = nullptr;
813  verify();
814 }
815 
817  ArrayRef<SlotIndex>::iterator SlotI = Slots.begin();
818  ArrayRef<SlotIndex>::iterator SlotE = Slots.end();
819 
820  // If there are no regmask slots, we have nothing to search.
821  if (SlotI == SlotE)
822  return false;
823 
824  // Start our search at the first segment that ends after the first slot.
825  const_iterator SegmentI = find(*SlotI);
826  const_iterator SegmentE = end();
827 
828  // If there are no segments that end after the first slot, we're done.
829  if (SegmentI == SegmentE)
830  return false;
831 
832  // Look for each slot in the live range.
833  for ( ; SlotI != SlotE; ++SlotI) {
834  // Go to the next segment that ends after the current slot.
835  // The slot may be within a hole in the range.
836  SegmentI = advanceTo(SegmentI, *SlotI);
837  if (SegmentI == SegmentE)
838  return false;
839 
840  // If this segment contains the slot, we're done.
841  if (SegmentI->contains(*SlotI))
842  return true;
843  // Otherwise, look for the next slot.
844  }
845 
846  // We didn't find a segment containing any of the slots.
847  return false;
848 }
849 
850 void LiveInterval::freeSubRange(SubRange *S) {
851  S->~SubRange();
852  // Memory was allocated with BumpPtr allocator and is not freed here.
853 }
854 
856  SubRange **NextPtr = &SubRanges;
857  SubRange *I = *NextPtr;
858  while (I != nullptr) {
859  if (!I->empty()) {
860  NextPtr = &I->Next;
861  I = *NextPtr;
862  continue;
863  }
864  // Skip empty subranges until we find the first nonempty one.
865  do {
866  SubRange *Next = I->Next;
867  freeSubRange(I);
868  I = Next;
869  } while (I != nullptr && I->empty());
870  *NextPtr = I;
871  }
872 }
873 
875  for (SubRange *I = SubRanges, *Next; I != nullptr; I = Next) {
876  Next = I->Next;
877  freeSubRange(I);
878  }
879  SubRanges = nullptr;
880 }
881 
883  LaneBitmask LaneMask, std::function<void(LiveInterval::SubRange&)> Apply) {
884  LaneBitmask ToApply = LaneMask;
885  for (SubRange &SR : subranges()) {
886  LaneBitmask SRMask = SR.LaneMask;
887  LaneBitmask Matching = SRMask & LaneMask;
888  if (Matching.none())
889  continue;
890 
891  SubRange *MatchingRange;
892  if (SRMask == Matching) {
893  // The subrange fits (it does not cover bits outside \p LaneMask).
894  MatchingRange = &SR;
895  } else {
896  // We have to split the subrange into a matching and non-matching part.
897  // Reduce lanemask of existing lane to non-matching part.
898  SR.LaneMask = SRMask & ~Matching;
899  // Create a new subrange for the matching part
900  MatchingRange = createSubRangeFrom(Allocator, Matching, SR);
901  }
902  Apply(*MatchingRange);
903  ToApply &= ~Matching;
904  }
905  // Create a new subrange if there are uncovered bits left.
906  if (ToApply.any()) {
907  SubRange *NewRange = createSubRange(Allocator, ToApply);
908  Apply(*NewRange);
909  }
910 }
911 
912 unsigned LiveInterval::getSize() const {
913  unsigned Sum = 0;
914  for (const Segment &S : segments)
915  Sum += S.start.distance(S.end);
916  return Sum;
917 }
918 
920  LaneBitmask LaneMask,
921  const MachineRegisterInfo &MRI,
922  const SlotIndexes &Indexes) const {
924  LaneBitmask VRegMask = MRI.getMaxLaneMaskForVReg(reg);
925  assert((VRegMask & LaneMask).any());
926  const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
927  for (const MachineOperand &MO : MRI.def_operands(reg)) {
928  if (!MO.isUndef())
929  continue;
930  unsigned SubReg = MO.getSubReg();
931  assert(SubReg != 0 && "Undef should only be set on subreg defs");
932  LaneBitmask DefMask = TRI.getSubRegIndexLaneMask(SubReg);
933  LaneBitmask UndefMask = VRegMask & ~DefMask;
934  if ((UndefMask & LaneMask).any()) {
935  const MachineInstr &MI = *MO.getParent();
936  bool EarlyClobber = MO.isEarlyClobber();
937  SlotIndex Pos = Indexes.getInstructionIndex(MI).getRegSlot(EarlyClobber);
938  Undefs.push_back(Pos);
939  }
940  }
941 }
942 
944  return OS << '[' << S.start << ',' << S.end << ':' << S.valno->id << ')';
945 }
946 
947 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
949  dbgs() << *this << '\n';
950 }
951 #endif
952 
953 void LiveRange::print(raw_ostream &OS) const {
954  if (empty())
955  OS << "EMPTY";
956  else {
957  for (const Segment &S : segments) {
958  OS << S;
959  assert(S.valno == getValNumInfo(S.valno->id) && "Bad VNInfo");
960  }
961  }
962 
963  // Print value number info.
964  if (getNumValNums()) {
965  OS << " ";
966  unsigned vnum = 0;
967  for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e;
968  ++i, ++vnum) {
969  const VNInfo *vni = *i;
970  if (vnum) OS << ' ';
971  OS << vnum << '@';
972  if (vni->isUnused()) {
973  OS << 'x';
974  } else {
975  OS << vni->def;
976  if (vni->isPHIDef())
977  OS << "-phi";
978  }
979  }
980  }
981 }
982 
984  OS << " L" << PrintLaneMask(LaneMask) << ' '
985  << static_cast<const LiveRange&>(*this);
986 }
987 
989  OS << PrintReg(reg) << ' ';
990  super::print(OS);
991  // Print subranges
992  for (const SubRange &SR : subranges())
993  OS << SR;
994 }
995 
996 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
998  dbgs() << *this << '\n';
999 }
1000 
1002  dbgs() << *this << '\n';
1003 }
1004 
1006  dbgs() << *this << '\n';
1007 }
1008 #endif
1009 
1010 #ifndef NDEBUG
1011 void LiveRange::verify() const {
1012  for (const_iterator I = begin(), E = end(); I != E; ++I) {
1013  assert(I->start.isValid());
1014  assert(I->end.isValid());
1015  assert(I->start < I->end);
1016  assert(I->valno != nullptr);
1017  assert(I->valno->id < valnos.size());
1018  assert(I->valno == valnos[I->valno->id]);
1019  if (std::next(I) != E) {
1020  assert(I->end <= std::next(I)->start);
1021  if (I->end == std::next(I)->start)
1022  assert(I->valno != std::next(I)->valno);
1023  }
1024  }
1025 }
1026 
1028  super::verify();
1029 
1030  // Make sure SubRanges are fine and LaneMasks are disjunct.
1031  LaneBitmask Mask;
1032  LaneBitmask MaxMask = MRI != nullptr ? MRI->getMaxLaneMaskForVReg(reg)
1033  : LaneBitmask::getAll();
1034  for (const SubRange &SR : subranges()) {
1035  // Subrange lanemask should be disjunct to any previous subrange masks.
1036  assert((Mask & SR.LaneMask).none());
1037  Mask |= SR.LaneMask;
1038 
1039  // subrange mask should not contained in maximum lane mask for the vreg.
1040  assert((Mask & ~MaxMask).none());
1041  // empty subranges must be removed.
1042  assert(!SR.empty());
1043 
1044  SR.verify();
1045  // Main liverange should cover subrange.
1046  assert(covers(SR));
1047  }
1048 }
1049 #endif
1050 
1051 //===----------------------------------------------------------------------===//
1052 // LiveRangeUpdater class
1053 //===----------------------------------------------------------------------===//
1054 //
1055 // The LiveRangeUpdater class always maintains these invariants:
1056 //
1057 // - When LastStart is invalid, Spills is empty and the iterators are invalid.
1058 // This is the initial state, and the state created by flush().
1059 // In this state, isDirty() returns false.
1060 //
1061 // Otherwise, segments are kept in three separate areas:
1062 //
1063 // 1. [begin; WriteI) at the front of LR.
1064 // 2. [ReadI; end) at the back of LR.
1065 // 3. Spills.
1066 //
1067 // - LR.begin() <= WriteI <= ReadI <= LR.end().
1068 // - Segments in all three areas are fully ordered and coalesced.
1069 // - Segments in area 1 precede and can't coalesce with segments in area 2.
1070 // - Segments in Spills precede and can't coalesce with segments in area 2.
1071 // - No coalescing is possible between segments in Spills and segments in area
1072 // 1, and there are no overlapping segments.
1073 //
1074 // The segments in Spills are not ordered with respect to the segments in area
1075 // 1. They need to be merged.
1076 //
1077 // When they exist, Spills.back().start <= LastStart,
1078 // and WriteI[-1].start <= LastStart.
1079 
1080 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1082  if (!isDirty()) {
1083  if (LR)
1084  OS << "Clean updater: " << *LR << '\n';
1085  else
1086  OS << "Null updater.\n";
1087  return;
1088  }
1089  assert(LR && "Can't have null LR in dirty updater.");
1090  OS << " updater with gap = " << (ReadI - WriteI)
1091  << ", last start = " << LastStart
1092  << ":\n Area 1:";
1093  for (const auto &S : make_range(LR->begin(), WriteI))
1094  OS << ' ' << S;
1095  OS << "\n Spills:";
1096  for (unsigned I = 0, E = Spills.size(); I != E; ++I)
1097  OS << ' ' << Spills[I];
1098  OS << "\n Area 2:";
1099  for (const auto &S : make_range(ReadI, LR->end()))
1100  OS << ' ' << S;
1101  OS << '\n';
1102 }
1103 
1105  print(errs());
1106 }
1107 #endif
1108 
1109 // Determine if A and B should be coalesced.
1110 static inline bool coalescable(const LiveRange::Segment &A,
1111  const LiveRange::Segment &B) {
1112  assert(A.start <= B.start && "Unordered live segments.");
1113  if (A.end == B.start)
1114  return A.valno == B.valno;
1115  if (A.end < B.start)
1116  return false;
1117  assert(A.valno == B.valno && "Cannot overlap different values");
1118  return true;
1119 }
1120 
1122  assert(LR && "Cannot add to a null destination");
1123 
1124  // Fall back to the regular add method if the live range
1125  // is using the segment set instead of the segment vector.
1126  if (LR->segmentSet != nullptr) {
1127  LR->addSegmentToSet(Seg);
1128  return;
1129  }
1130 
1131  // Flush the state if Start moves backwards.
1132  if (!LastStart.isValid() || LastStart > Seg.start) {
1133  if (isDirty())
1134  flush();
1135  // This brings us to an uninitialized state. Reinitialize.
1136  assert(Spills.empty() && "Leftover spilled segments");
1137  WriteI = ReadI = LR->begin();
1138  }
1139 
1140  // Remember start for next time.
1141  LastStart = Seg.start;
1142 
1143  // Advance ReadI until it ends after Seg.start.
1144  LiveRange::iterator E = LR->end();
1145  if (ReadI != E && ReadI->end <= Seg.start) {
1146  // First try to close the gap between WriteI and ReadI with spills.
1147  if (ReadI != WriteI)
1148  mergeSpills();
1149  // Then advance ReadI.
1150  if (ReadI == WriteI)
1151  ReadI = WriteI = LR->find(Seg.start);
1152  else
1153  while (ReadI != E && ReadI->end <= Seg.start)
1154  *WriteI++ = *ReadI++;
1155  }
1156 
1157  assert(ReadI == E || ReadI->end > Seg.start);
1158 
1159  // Check if the ReadI segment begins early.
1160  if (ReadI != E && ReadI->start <= Seg.start) {
1161  assert(ReadI->valno == Seg.valno && "Cannot overlap different values");
1162  // Bail if Seg is completely contained in ReadI.
1163  if (ReadI->end >= Seg.end)
1164  return;
1165  // Coalesce into Seg.
1166  Seg.start = ReadI->start;
1167  ++ReadI;
1168  }
1169 
1170  // Coalesce as much as possible from ReadI into Seg.
1171  while (ReadI != E && coalescable(Seg, *ReadI)) {
1172  Seg.end = std::max(Seg.end, ReadI->end);
1173  ++ReadI;
1174  }
1175 
1176  // Try coalescing Spills.back() into Seg.
1177  if (!Spills.empty() && coalescable(Spills.back(), Seg)) {
1178  Seg.start = Spills.back().start;
1179  Seg.end = std::max(Spills.back().end, Seg.end);
1180  Spills.pop_back();
1181  }
1182 
1183  // Try coalescing Seg into WriteI[-1].
1184  if (WriteI != LR->begin() && coalescable(WriteI[-1], Seg)) {
1185  WriteI[-1].end = std::max(WriteI[-1].end, Seg.end);
1186  return;
1187  }
1188 
1189  // Seg doesn't coalesce with anything, and needs to be inserted somewhere.
1190  if (WriteI != ReadI) {
1191  *WriteI++ = Seg;
1192  return;
1193  }
1194 
1195  // Finally, append to LR or Spills.
1196  if (WriteI == E) {
1197  LR->segments.push_back(Seg);
1198  WriteI = ReadI = LR->end();
1199  } else
1200  Spills.push_back(Seg);
1201 }
1202 
1203 // Merge as many spilled segments as possible into the gap between WriteI
1204 // and ReadI. Advance WriteI to reflect the inserted instructions.
1205 void LiveRangeUpdater::mergeSpills() {
1206  // Perform a backwards merge of Spills and [SpillI;WriteI).
1207  size_t GapSize = ReadI - WriteI;
1208  size_t NumMoved = std::min(Spills.size(), GapSize);
1209  LiveRange::iterator Src = WriteI;
1210  LiveRange::iterator Dst = Src + NumMoved;
1211  LiveRange::iterator SpillSrc = Spills.end();
1212  LiveRange::iterator B = LR->begin();
1213 
1214  // This is the new WriteI position after merging spills.
1215  WriteI = Dst;
1216 
1217  // Now merge Src and Spills backwards.
1218  while (Src != Dst) {
1219  if (Src != B && Src[-1].start > SpillSrc[-1].start)
1220  *--Dst = *--Src;
1221  else
1222  *--Dst = *--SpillSrc;
1223  }
1224  assert(NumMoved == size_t(Spills.end() - SpillSrc));
1225  Spills.erase(SpillSrc, Spills.end());
1226 }
1227 
1229  if (!isDirty())
1230  return;
1231  // Clear the dirty state.
1232  LastStart = SlotIndex();
1233 
1234  assert(LR && "Cannot add to a null destination");
1235 
1236  // Nothing to merge?
1237  if (Spills.empty()) {
1238  LR->segments.erase(WriteI, ReadI);
1239  LR->verify();
1240  return;
1241  }
1242 
1243  // Resize the WriteI - ReadI gap to match Spills.
1244  size_t GapSize = ReadI - WriteI;
1245  if (GapSize < Spills.size()) {
1246  // The gap is too small. Make some room.
1247  size_t WritePos = WriteI - LR->begin();
1248  LR->segments.insert(ReadI, Spills.size() - GapSize, LiveRange::Segment());
1249  // This also invalidated ReadI, but it is recomputed below.
1250  WriteI = LR->begin() + WritePos;
1251  } else {
1252  // Shrink the gap if necessary.
1253  LR->segments.erase(WriteI + Spills.size(), ReadI);
1254  }
1255  ReadI = WriteI + Spills.size();
1256  mergeSpills();
1257  LR->verify();
1258 }
1259 
1261  // Create initial equivalence classes.
1262  EqClass.clear();
1263  EqClass.grow(LR.getNumValNums());
1264 
1265  const VNInfo *used = nullptr, *unused = nullptr;
1266 
1267  // Determine connections.
1268  for (const VNInfo *VNI : LR.valnos) {
1269  // Group all unused values into one class.
1270  if (VNI->isUnused()) {
1271  if (unused)
1272  EqClass.join(unused->id, VNI->id);
1273  unused = VNI;
1274  continue;
1275  }
1276  used = VNI;
1277  if (VNI->isPHIDef()) {
1278  const MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
1279  assert(MBB && "Phi-def has no defining MBB");
1280  // Connect to values live out of predecessors.
1282  PE = MBB->pred_end(); PI != PE; ++PI)
1283  if (const VNInfo *PVNI = LR.getVNInfoBefore(LIS.getMBBEndIdx(*PI)))
1284  EqClass.join(VNI->id, PVNI->id);
1285  } else {
1286  // Normal value defined by an instruction. Check for two-addr redef.
1287  // FIXME: This could be coincidental. Should we really check for a tied
1288  // operand constraint?
1289  // Note that VNI->def may be a use slot for an early clobber def.
1290  if (const VNInfo *UVNI = LR.getVNInfoBefore(VNI->def))
1291  EqClass.join(VNI->id, UVNI->id);
1292  }
1293  }
1294 
1295  // Lump all the unused values in with the last used value.
1296  if (used && unused)
1297  EqClass.join(used->id, unused->id);
1298 
1299  EqClass.compress();
1300  return EqClass.getNumClasses();
1301 }
1302 
1305  // Rewrite instructions.
1307  RE = MRI.reg_end(); RI != RE;) {
1308  MachineOperand &MO = *RI;
1309  MachineInstr *MI = RI->getParent();
1310  ++RI;
1311  // DBG_VALUE instructions don't have slot indexes, so get the index of the
1312  // instruction before them.
1313  // Normally, DBG_VALUE instructions are removed before this function is
1314  // called, but it is not a requirement.
1315  SlotIndex Idx;
1316  if (MI->isDebugValue())
1317  Idx = LIS.getSlotIndexes()->getIndexBefore(*MI);
1318  else
1319  Idx = LIS.getInstructionIndex(*MI);
1320  LiveQueryResult LRQ = LI.Query(Idx);
1321  const VNInfo *VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();
1322  // In the case of an <undef> use that isn't tied to any def, VNI will be
1323  // NULL. If the use is tied to a def, VNI will be the defined value.
1324  if (!VNI)
1325  continue;
1326  if (unsigned EqClass = getEqClass(VNI))
1327  MO.setReg(LIV[EqClass-1]->reg);
1328  }
1329 
1330  // Distribute subregister liveranges.
1331  if (LI.hasSubRanges()) {
1332  unsigned NumComponents = EqClass.getNumClasses();
1333  SmallVector<unsigned, 8> VNIMapping;
1335  BumpPtrAllocator &Allocator = LIS.getVNInfoAllocator();
1336  for (LiveInterval::SubRange &SR : LI.subranges()) {
1337  // Create new subranges in the split intervals and construct a mapping
1338  // for the VNInfos in the subrange.
1339  unsigned NumValNos = SR.valnos.size();
1340  VNIMapping.clear();
1341  VNIMapping.reserve(NumValNos);
1342  SubRanges.clear();
1343  SubRanges.resize(NumComponents-1, nullptr);
1344  for (unsigned I = 0; I < NumValNos; ++I) {
1345  const VNInfo &VNI = *SR.valnos[I];
1346  unsigned ComponentNum;
1347  if (VNI.isUnused()) {
1348  ComponentNum = 0;
1349  } else {
1350  const VNInfo *MainRangeVNI = LI.getVNInfoAt(VNI.def);
1351  assert(MainRangeVNI != nullptr
1352  && "SubRange def must have corresponding main range def");
1353  ComponentNum = getEqClass(MainRangeVNI);
1354  if (ComponentNum > 0 && SubRanges[ComponentNum-1] == nullptr) {
1355  SubRanges[ComponentNum-1]
1356  = LIV[ComponentNum-1]->createSubRange(Allocator, SR.LaneMask);
1357  }
1358  }
1359  VNIMapping.push_back(ComponentNum);
1360  }
1361  DistributeRange(SR, SubRanges.data(), VNIMapping);
1362  }
1363  LI.removeEmptySubRanges();
1364  }
1365 
1366  // Distribute main liverange.
1367  DistributeRange(LI, LIV, EqClass);
1368 }
void add(LiveRange::Segment)
Add a segment to LR and coalesce when possible, just like LR.addSegment().
std::set< Segment > SegmentSet
Definition: LiveInterval.h:205
void RenumberValues()
RenumberValues - Renumber all values in order of appearance and remove unused values.
bool empty() const
Definition: LiveInterval.h:370
bool isPHIDef() const
Returns true if this value is defined by a PHI instruction (or was, PHI instructions may have been el...
Definition: LiveInterval.h:78
void push_back(const T &Elt)
Definition: SmallVector.h:212
const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:244
A common definition of LaneBitmask for use in TableGen and CodeGen.
void flush()
Flush the updater state to LR so it is valid and contains all added segments.
raw_ostream & errs()
This returns a reference to a raw_ostream for standard error.
GCNRegPressure max(const GCNRegPressure &P1, const GCNRegPressure &P2)
const unsigned reg
Definition: LiveInterval.h:667
const_iterator begin(StringRef path, Style style=Style::native)
Get begin iterator over path.
Definition: Path.cpp:235
void refineSubRanges(BumpPtrAllocator &Allocator, LaneBitmask LaneMask, std::function< void(LiveInterval::SubRange &)> Mod)
Refines the subranges to support LaneMask.
SlotIndex def
The index of the defining instruction.
Definition: LiveInterval.h:61
LaneBitmask getMaxLaneMaskForVReg(unsigned Reg) const
Returns a mask covering all bits that can appear in lane masks of subregisters of the virtual registe...
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
static bool coalescable(const LiveRange::Segment &A, const LiveRange::Segment &B)
#define LLVM_DUMP_METHOD
Mark debug helper function definitions like dump() that should not be stripped from debug builds...
Definition: Compiler.h:449
iterator begin() const
Definition: ArrayRef.h:137
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:136
bool isCoalescable(const MachineInstr *) const
Return true if MI is a copy instruction that will become an identity copy after coalescing.
void MergeValueInAsValue(const LiveRange &RHS, const VNInfo *RHSValNo, VNInfo *LHSValNo)
MergeValueInAsValue - Merge all of the segments of a specific val# in RHS into this live range as the...
auto remove_if(R &&Range, UnaryPredicate P) -> decltype(std::begin(Range))
Provide wrappers to std::remove_if which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:807
Segments::iterator iterator
Definition: LiveInterval.h:208
static LaneBitmask getAll()
Definition: LaneBitmask.h:84
bool isUndefIn(ArrayRef< SlotIndex > Undefs, SlotIndex Begin, SlotIndex End) const
Returns true if there is an explicit "undef" between Begin End.
Definition: LiveInterval.h:595
LiveInterval - This class represents the liveness of a register, or stack slot.
Definition: LiveInterval.h:638
This provides a very simple, boring adaptor for a begin and end iterator into a range type...
static bool isVirtualRegister(unsigned Reg)
Return true if the specified register number is in the virtual register namespace.
bool isDead() const
isDead - Returns true if this is a dead def kill slot.
Definition: SlotIndexes.h:237
bool isLiveAtIndexes(ArrayRef< SlotIndex > Slots) const
A live range for subregisters.
Definition: LiveInterval.h:645
This represents a simple continuous liveness interval for a value.
Definition: LiveInterval.h:162
Printable PrintLaneMask(LaneBitmask LaneMask)
Create Printable object to print LaneBitmasks on a raw_ostream.
Definition: LaneBitmask.h:94
void markUnused()
Mark this value as unused.
Definition: LiveInterval.h:84
std::vector< MachineBasicBlock * >::const_iterator const_pred_iterator
void reserve(size_type N)
Definition: SmallVector.h:380
VNInfo - Value Number Information.
Definition: LiveInterval.h:53
void flushSegmentSet()
Flush segment set into the regular segment vector.
void Distribute(LiveInterval &LI, LiveInterval *LIV[], MachineRegisterInfo &MRI)
Distribute values in LI into a separate LiveIntervals for each connected component.
This class represents the liveness of a register, stack slot, etc.
Definition: LiveInterval.h:157
bool isUnused() const
Returns true if this value is unused.
Definition: LiveInterval.h:81
bool overlapsFrom(const LiveRange &Other, const_iterator I) const
overlapsFrom - Return true if the intersection of the two live ranges is not empty.
static bool isEarlierInstr(SlotIndex A, SlotIndex B)
isEarlierInstr - Return true if A refers to an instruction earlier than B.
Definition: SlotIndexes.h:204
void removeEmptySubRanges()
Removes all subranges without any segments (subranges without segments are not considered valid and s...
bool isBlock() const
isBlock - Returns true if this is a block boundary slot.
Definition: SlotIndexes.h:227
void verify() const
Walk the range and assert if any invariants fail to hold.
SlotIndex getDeadSlot() const
Returns the dead def kill slot for the current instruction.
Definition: SlotIndexes.h:260
A Use represents the edge between a Value definition and its users.
Definition: Use.h:56
iterator end()
Definition: LiveInterval.h:212
A helper class for register coalescers.
iterator_range< subrange_iterator > subranges()
Definition: LiveInterval.h:723
unsigned SubReg
Result of a LiveRange query.
Definition: LiveInterval.h:90
SlotIndex getInstructionIndex(const MachineInstr &MI) const
Returns the base index for the given instruction.
Definition: SlotIndexes.h:414
bool hasSubRanges() const
Returns true if subregister liveness information is available.
Definition: LiveInterval.h:751
void MergeSegmentsInAsValue(const LiveRange &RHS, VNInfo *LHSValNo)
Merge all of the live segments of a specific val# in RHS into this live range as the specified value ...
place backedge safepoints impl
bool readsReg() const
readsReg - Returns true if this operand reads the previous value of its register. ...
SlotIndexes pass.
Definition: SlotIndexes.h:331
SlotIndex getRegSlot(bool EC=false) const
Returns the register use/def slot in the current instruction for a normal or early-clobber def...
Definition: SlotIndexes.h:255
iterator addSegment(Segment S)
Add the specified Segment to this range, merging segments as appropriate.
Segments segments
Definition: LiveInterval.h:199
iterator_range< def_iterator > def_operands(unsigned Reg) const
VNInfo * MergeValueNumberInto(VNInfo *V1, VNInfo *V2)
MergeValueNumberInto - This method is called when two value numbers are found to be equivalent...
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:33
SlotIndex getNextSlot() const
Returns the next slot in the index list.
Definition: SlotIndexes.h:270
Printable PrintReg(unsigned Reg, const TargetRegisterInfo *TRI=nullptr, unsigned SubRegIdx=0)
Prints virtual and physical registers with or without a TRI instance.
void print(raw_ostream &OS) const
static void DistributeRange(LiveRangeT &LR, LiveRangeT *SplitLRs[], EqClassesT VNIClasses)
Helper function that distributes live range value numbers and the corresponding segments of a master ...
void copyFrom(VNInfo &src)
Copy from the parameter into this VNInfo.
Definition: LiveInterval.h:70
VNInfo * valueIn() const
Return the value that is live-in to the instruction.
Definition: LiveInterval.h:105
LiveQueryResult Query(SlotIndex Idx) const
Query Liveness at Idx.
Definition: LiveInterval.h:529
VNInfo * getVNInfoAt(SlotIndex Idx) const
getVNInfoAt - Return the VNInfo that is live at Idx, or NULL.
Definition: LiveInterval.h:409
void removeValNo(VNInfo *ValNo)
removeValNo - Remove all the segments defined by the specified value#.
MachineInstr * getInstructionFromIndex(SlotIndex index) const
Returns the instruction for the given index, or null if the given index has no instruction associated...
Definition: SlotIndexes.h:424
friend const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:244
const TargetRegisterInfo * getTargetRegisterInfo() const
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
SubRange * createSubRange(BumpPtrAllocator &Allocator, LaneBitmask LaneMask)
Creates a new empty subregister live range.
Definition: LiveInterval.h:733
unsigned const MachineRegisterInfo * MRI
VNInfoList::const_iterator const_vni_iterator
Definition: LiveInterval.h:218
void print(raw_ostream &OS) const
Allocate memory in an ever growing pool, as if by bump-pointer.
Definition: Allocator.h:138
std::pair< VNInfo *, bool > extendInBlock(ArrayRef< SlotIndex > Undefs, SlotIndex StartIdx, SlotIndex Use)
Attempt to extend a value defined after StartIdx to include Use.
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
unsigned Classify(const LiveRange &LR)
Classify the values in LR into connected components.
std::pair< iterator, bool > insert(PtrType Ptr)
Inserts Ptr if and only if there is no element in the container equal to Ptr.
Definition: SmallPtrSet.h:371
constexpr bool none() const
Definition: LaneBitmask.h:52
static const unsigned End
void append(const LiveRange::Segment S)
Append a segment to the list of segments.
static void print(raw_ostream &Out, object::Archive::Kind Kind, T Val)
void join(LiveRange &Other, const int *ValNoAssignments, const int *RHSValNoAssignments, SmallVectorImpl< VNInfo *> &NewVNInfo)
join - Join two live ranges (this, and other) together.
iterator erase(const_iterator CI)
Definition: SmallVector.h:449
void print(raw_ostream &) const
TargetRegisterInfo base class - We assume that the target defines a static array of TargetRegisterDes...
bool verify(const TargetRegisterInfo &TRI) const
Check that information hold by this instance make sense for the given TRI.
iterator find(SlotIndex Pos)
find - Return an iterator pointing to the first segment that ends after Pos, or end().
unsigned id
The ID number of this value.
Definition: LiveInterval.h:58
void removeSegment(SlotIndex Start, SlotIndex End, bool RemoveDeadValNo=false)
Remove the specified segment from this range.
iterator_range< T > make_range(T x, T y)
Convenience function for iterating over sub-ranges.
Basic Register Allocator
bool covers(const LiveRange &Other) const
Returns true if all segments of the Other live range are completely covered by this live range...
SmallPtrSet - This class implements a set which is optimized for holding SmallSize or less elements...
Definition: SmallPtrSet.h:418
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:788
static bool isSameInstr(SlotIndex A, SlotIndex B)
isSameInstr - Return true if A and B refer to the same instruction.
Definition: SlotIndexes.h:198
Segments::const_iterator const_iterator
Definition: LiveInterval.h:209
bool isDebugValue() const
Definition: MachineInstr.h:816
MachineOperand class - Representation of each machine instruction operand.
iterator end() const
Definition: ArrayRef.h:138
reg_iterator reg_begin(unsigned RegNo) const
std::unique_ptr< SegmentSet > segmentSet
Definition: LiveInterval.h:206
LaneBitmask getSubRegIndexLaneMask(unsigned SubIdx) const
Return a bitmask representing the parts of a register that are covered by SubIdx. ...
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
void clearSubRanges()
Removes all subregister liveness information.
void swap(llvm::BitVector &LHS, llvm::BitVector &RHS)
Implement std::swap in terms of BitVector swap.
Definition: BitVector.h:923
unsigned getSize() const
getSize - Returns the sum of sizes of all the LiveRange&#39;s.
VNInfo * getVNInfoBefore(SlotIndex Idx) const
getVNInfoBefore - Return the VNInfo that is live up to but not necessarilly including Idx...
Definition: LiveInterval.h:417
void computeSubRangeUndefs(SmallVectorImpl< SlotIndex > &Undefs, LaneBitmask LaneMask, const MachineRegisterInfo &MRI, const SlotIndexes &Indexes) const
For a given lane mask LaneMask, compute indexes at which the lane is marked undefined by subregister ...
auto lower_bound(R &&Range, ForwardIt I) -> decltype(std::begin(Range))
Provide wrappers to std::lower_bound which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:859
VNInfoList valnos
Definition: LiveInterval.h:200
iterator insert(iterator I, T &&Elt)
Definition: SmallVector.h:482
MachineRegisterInfo - Keep track of information for virtual and physical registers, including vreg register classes, use/def chains for registers, etc.
unsigned getNumValNums() const
Definition: LiveInterval.h:301
Representation of each machine instruction.
Definition: MachineInstr.h:59
pointer data()
Return a pointer to the vector&#39;s buffer, even if empty().
Definition: SmallVector.h:143
bool overlaps(const LiveRange &other) const
overlaps - Return true if the intersection of the two live ranges is not empty.
Definition: LiveInterval.h:436
SlotIndex getPrevSlot() const
Returns the previous slot in the index list.
Definition: SlotIndexes.h:290
VNInfo * createDeadDef(SlotIndex Def, VNInfo::Allocator &VNInfoAllocator)
createDeadDef - Make sure the range has a value defined at Def.
void setReg(unsigned Reg)
Change the register this operand corresponds to.
#define I(x, y, z)
Definition: MD5.cpp:58
constexpr bool any() const
Definition: LaneBitmask.h:53
static void createDeadDef(SlotIndexes &Indexes, VNInfo::Allocator &Alloc, LiveRange &LR, const MachineOperand &MO)
raw_ostream & operator<<(raw_ostream &OS, const APInt &I)
Definition: APInt.h:2018
iterator begin()
Definition: LiveInterval.h:211
Helper class for performant LiveRange bulk updates.
Definition: LiveInterval.h:854
VNInfo * getNextValue(SlotIndex def, VNInfo::Allocator &VNInfoAllocator)
getNextValue - Create a new value number and return it.
Definition: LiveInterval.h:319
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
SlotIndex beginIndex() const
beginIndex - Return the lowest numbered slot covered.
Definition: LiveInterval.h:373
std::underlying_type< E >::type Mask()
Get a bitmask with 1s in all places up to the high-order bit of E&#39;s largest value.
Definition: BitmaskEnum.h:81
void dump() const
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:44
print Print MemDeps of function
IRTranslator LLVM IR MI
ppc ctr loops verify
VNInfo * valueDefined() const
Return the value defined by this instruction, if any.
Definition: LiveInterval.h:135
static reg_iterator reg_end()
void print(raw_ostream &OS) const
SlotIndex - An opaque wrapper around machine indexes.
Definition: SlotIndexes.h:84
reg_begin/reg_end - Provide iteration support to walk over all definitions and uses of a register wit...
void resize(size_type N)
Definition: SmallVector.h:355