LLVM  10.0.0svn
LiveInterval.cpp
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1 //===- LiveInterval.cpp - Live Interval Representation --------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements the LiveRange and LiveInterval classes. Given some
10 // numbering of each the machine instructions an interval [i, j) is said to be a
11 // live range for register v if there is no instruction with number j' >= j
12 // such that v is live at j' and there is no instruction with number i' < i such
13 // that v is live at i'. In this implementation ranges can have holes,
14 // i.e. a range might look like [1,20), [50,65), [1000,1001). Each
15 // individual segment is represented as an instance of LiveRange::Segment,
16 // and the whole range is represented as an instance of LiveRange.
17 //
18 //===----------------------------------------------------------------------===//
19 
21 #include "LiveRangeUtils.h"
22 #include "RegisterCoalescer.h"
23 #include "llvm/ADT/ArrayRef.h"
24 #include "llvm/ADT/STLExtras.h"
25 #include "llvm/ADT/SmallPtrSet.h"
26 #include "llvm/ADT/SmallVector.h"
35 #include "llvm/Config/llvm-config.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) { return llvm::upper_bound(*LR, S.start); }
300 };
301 
302 //===----------------------------------------------------------------------===//
303 // Instantiation of the methods for calculation of live ranges
304 // based on a segment set.
305 //===----------------------------------------------------------------------===//
306 
307 class CalcLiveRangeUtilSet;
308 using CalcLiveRangeUtilSetBase =
309  CalcLiveRangeUtilBase<CalcLiveRangeUtilSet, LiveRange::SegmentSet::iterator,
311 
312 class CalcLiveRangeUtilSet : public CalcLiveRangeUtilSetBase {
313 public:
314  CalcLiveRangeUtilSet(LiveRange *LR) : CalcLiveRangeUtilSetBase(LR) {}
315 
316 private:
317  friend CalcLiveRangeUtilSetBase;
318 
319  LiveRange::SegmentSet &segmentsColl() { return *LR->segmentSet; }
320 
321  void insertAtEnd(const Segment &S) {
322  LR->segmentSet->insert(LR->segmentSet->end(), S);
323  }
324 
325  iterator find(SlotIndex Pos) {
326  iterator I =
327  LR->segmentSet->upper_bound(Segment(Pos, Pos.getNextSlot(), nullptr));
328  if (I == LR->segmentSet->begin())
329  return I;
330  iterator PrevI = std::prev(I);
331  if (Pos < (*PrevI).end)
332  return PrevI;
333  return I;
334  }
335 
336  iterator findInsertPos(Segment S) {
337  iterator I = LR->segmentSet->upper_bound(S);
338  if (I != LR->segmentSet->end() && !(S.start < *I))
339  ++I;
340  return I;
341  }
342 };
343 
344 } // end anonymous namespace
345 
346 //===----------------------------------------------------------------------===//
347 // LiveRange methods
348 //===----------------------------------------------------------------------===//
349 
350 LiveRange::iterator LiveRange::find(SlotIndex Pos) {
351  // This algorithm is basically std::upper_bound.
352  // Unfortunately, std::upper_bound cannot be used with mixed types until we
353  // adopt C++0x. Many libraries can do it, but not all.
354  if (empty() || Pos >= endIndex())
355  return end();
356  iterator I = begin();
357  size_t Len = size();
358  do {
359  size_t Mid = Len >> 1;
360  if (Pos < I[Mid].end) {
361  Len = Mid;
362  } else {
363  I += Mid + 1;
364  Len -= Mid + 1;
365  }
366  } while (Len);
367  return I;
368 }
369 
371  // Use the segment set, if it is available.
372  if (segmentSet != nullptr)
373  return CalcLiveRangeUtilSet(this).createDeadDef(Def, &VNIAlloc, nullptr);
374  // Otherwise use the segment vector.
375  return CalcLiveRangeUtilVector(this).createDeadDef(Def, &VNIAlloc, nullptr);
376 }
377 
379  // Use the segment set, if it is available.
380  if (segmentSet != nullptr)
381  return CalcLiveRangeUtilSet(this).createDeadDef(VNI->def, nullptr, VNI);
382  // Otherwise use the segment vector.
383  return CalcLiveRangeUtilVector(this).createDeadDef(VNI->def, nullptr, VNI);
384 }
385 
386 // overlaps - Return true if the intersection of the two live ranges is
387 // not empty.
388 //
389 // An example for overlaps():
390 //
391 // 0: A = ...
392 // 4: B = ...
393 // 8: C = A + B ;; last use of A
394 //
395 // The live ranges should look like:
396 //
397 // A = [3, 11)
398 // B = [7, x)
399 // C = [11, y)
400 //
401 // A->overlaps(C) should return false since we want to be able to join
402 // A and C.
403 //
405  const_iterator StartPos) const {
406  assert(!empty() && "empty range");
407  const_iterator i = begin();
408  const_iterator ie = end();
409  const_iterator j = StartPos;
410  const_iterator je = other.end();
411 
412  assert((StartPos->start <= i->start || StartPos == other.begin()) &&
413  StartPos != other.end() && "Bogus start position hint!");
414 
415  if (i->start < j->start) {
416  i = std::upper_bound(i, ie, j->start);
417  if (i != begin()) --i;
418  } else if (j->start < i->start) {
419  ++StartPos;
420  if (StartPos != other.end() && StartPos->start <= i->start) {
421  assert(StartPos < other.end() && i < end());
422  j = std::upper_bound(j, je, i->start);
423  if (j != other.begin()) --j;
424  }
425  } else {
426  return true;
427  }
428 
429  if (j == je) return false;
430 
431  while (i != ie) {
432  if (i->start > j->start) {
433  std::swap(i, j);
434  std::swap(ie, je);
435  }
436 
437  if (i->end > j->start)
438  return true;
439  ++i;
440  }
441 
442  return false;
443 }
444 
445 bool LiveRange::overlaps(const LiveRange &Other, const CoalescerPair &CP,
446  const SlotIndexes &Indexes) const {
447  assert(!empty() && "empty range");
448  if (Other.empty())
449  return false;
450 
451  // Use binary searches to find initial positions.
452  const_iterator I = find(Other.beginIndex());
453  const_iterator IE = end();
454  if (I == IE)
455  return false;
456  const_iterator J = Other.find(I->start);
457  const_iterator JE = Other.end();
458  if (J == JE)
459  return false;
460 
461  while (true) {
462  // J has just been advanced to satisfy:
463  assert(J->end >= I->start);
464  // Check for an overlap.
465  if (J->start < I->end) {
466  // I and J are overlapping. Find the later start.
467  SlotIndex Def = std::max(I->start, J->start);
468  // Allow the overlap if Def is a coalescable copy.
469  if (Def.isBlock() ||
470  !CP.isCoalescable(Indexes.getInstructionFromIndex(Def)))
471  return true;
472  }
473  // Advance the iterator that ends first to check for more overlaps.
474  if (J->end > I->end) {
475  std::swap(I, J);
476  std::swap(IE, JE);
477  }
478  // Advance J until J->end >= I->start.
479  do
480  if (++J == JE)
481  return false;
482  while (J->end < I->start);
483  }
484 }
485 
486 /// overlaps - Return true if the live range overlaps an interval specified
487 /// by [Start, End).
488 bool LiveRange::overlaps(SlotIndex Start, SlotIndex End) const {
489  assert(Start < End && "Invalid range");
490  const_iterator I = std::lower_bound(begin(), end(), End);
491  return I != begin() && (--I)->end > Start;
492 }
493 
494 bool LiveRange::covers(const LiveRange &Other) const {
495  if (empty())
496  return Other.empty();
497 
498  const_iterator I = begin();
499  for (const Segment &O : Other.segments) {
500  I = advanceTo(I, O.start);
501  if (I == end() || I->start > O.start)
502  return false;
503 
504  // Check adjacent live segments and see if we can get behind O.end.
505  while (I->end < O.end) {
506  const_iterator Last = I;
507  // Get next segment and abort if it was not adjacent.
508  ++I;
509  if (I == end() || Last->end != I->start)
510  return false;
511  }
512  }
513  return true;
514 }
515 
516 /// ValNo is dead, remove it. If it is the largest value number, just nuke it
517 /// (and any other deleted values neighboring it), otherwise mark it as ~1U so
518 /// it can be nuked later.
519 void LiveRange::markValNoForDeletion(VNInfo *ValNo) {
520  if (ValNo->id == getNumValNums()-1) {
521  do {
522  valnos.pop_back();
523  } while (!valnos.empty() && valnos.back()->isUnused());
524  } else {
525  ValNo->markUnused();
526  }
527 }
528 
529 /// RenumberValues - Renumber all values in order of appearance and delete the
530 /// remaining unused values.
533  valnos.clear();
534  for (const Segment &S : segments) {
535  VNInfo *VNI = S.valno;
536  if (!Seen.insert(VNI).second)
537  continue;
538  assert(!VNI->isUnused() && "Unused valno used by live segment");
539  VNI->id = (unsigned)valnos.size();
540  valnos.push_back(VNI);
541  }
542 }
543 
544 void LiveRange::addSegmentToSet(Segment S) {
545  CalcLiveRangeUtilSet(this).addSegment(S);
546 }
547 
548 LiveRange::iterator LiveRange::addSegment(Segment S) {
549  // Use the segment set, if it is available.
550  if (segmentSet != nullptr) {
551  addSegmentToSet(S);
552  return end();
553  }
554  // Otherwise use the segment vector.
555  return CalcLiveRangeUtilVector(this).addSegment(S);
556 }
557 
558 void LiveRange::append(const Segment S) {
559  // Check that the segment belongs to the back of the list.
560  assert(segments.empty() || segments.back().end <= S.start);
561  segments.push_back(S);
562 }
563 
564 std::pair<VNInfo*,bool> LiveRange::extendInBlock(ArrayRef<SlotIndex> Undefs,
565  SlotIndex StartIdx, SlotIndex Kill) {
566  // Use the segment set, if it is available.
567  if (segmentSet != nullptr)
568  return CalcLiveRangeUtilSet(this).extendInBlock(Undefs, StartIdx, Kill);
569  // Otherwise use the segment vector.
570  return CalcLiveRangeUtilVector(this).extendInBlock(Undefs, StartIdx, Kill);
571 }
572 
574  // Use the segment set, if it is available.
575  if (segmentSet != nullptr)
576  return CalcLiveRangeUtilSet(this).extendInBlock(StartIdx, Kill);
577  // Otherwise use the segment vector.
578  return CalcLiveRangeUtilVector(this).extendInBlock(StartIdx, Kill);
579 }
580 
581 /// Remove the specified segment from this range. Note that the segment must
582 /// be in a single Segment in its entirety.
584  bool RemoveDeadValNo) {
585  // Find the Segment containing this span.
586  iterator I = find(Start);
587  assert(I != end() && "Segment is not in range!");
588  assert(I->containsInterval(Start, End)
589  && "Segment is not entirely in range!");
590 
591  // If the span we are removing is at the start of the Segment, adjust it.
592  VNInfo *ValNo = I->valno;
593  if (I->start == Start) {
594  if (I->end == End) {
595  if (RemoveDeadValNo) {
596  // Check if val# is dead.
597  bool isDead = true;
598  for (const_iterator II = begin(), EE = end(); II != EE; ++II)
599  if (II != I && II->valno == ValNo) {
600  isDead = false;
601  break;
602  }
603  if (isDead) {
604  // Now that ValNo is dead, remove it.
605  markValNoForDeletion(ValNo);
606  }
607  }
608 
609  segments.erase(I); // Removed the whole Segment.
610  } else
611  I->start = End;
612  return;
613  }
614 
615  // Otherwise if the span we are removing is at the end of the Segment,
616  // adjust the other way.
617  if (I->end == End) {
618  I->end = Start;
619  return;
620  }
621 
622  // Otherwise, we are splitting the Segment into two pieces.
623  SlotIndex OldEnd = I->end;
624  I->end = Start; // Trim the old segment.
625 
626  // Insert the new one.
627  segments.insert(std::next(I), Segment(End, OldEnd, ValNo));
628 }
629 
630 /// removeValNo - Remove all the segments defined by the specified value#.
631 /// Also remove the value# from value# list.
633  if (empty()) return;
634  segments.erase(remove_if(*this, [ValNo](const Segment &S) {
635  return S.valno == ValNo;
636  }), end());
637  // Now that ValNo is dead, remove it.
638  markValNoForDeletion(ValNo);
639 }
640 
642  const int *LHSValNoAssignments,
643  const int *RHSValNoAssignments,
644  SmallVectorImpl<VNInfo *> &NewVNInfo) {
645  verify();
646 
647  // Determine if any of our values are mapped. This is uncommon, so we want
648  // to avoid the range scan if not.
649  bool MustMapCurValNos = false;
650  unsigned NumVals = getNumValNums();
651  unsigned NumNewVals = NewVNInfo.size();
652  for (unsigned i = 0; i != NumVals; ++i) {
653  unsigned LHSValID = LHSValNoAssignments[i];
654  if (i != LHSValID ||
655  (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) {
656  MustMapCurValNos = true;
657  break;
658  }
659  }
660 
661  // If we have to apply a mapping to our base range assignment, rewrite it now.
662  if (MustMapCurValNos && !empty()) {
663  // Map the first live range.
664 
665  iterator OutIt = begin();
666  OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]];
667  for (iterator I = std::next(OutIt), E = end(); I != E; ++I) {
668  VNInfo* nextValNo = NewVNInfo[LHSValNoAssignments[I->valno->id]];
669  assert(nextValNo && "Huh?");
670 
671  // If this live range has the same value # as its immediate predecessor,
672  // and if they are neighbors, remove one Segment. This happens when we
673  // have [0,4:0)[4,7:1) and map 0/1 onto the same value #.
674  if (OutIt->valno == nextValNo && OutIt->end == I->start) {
675  OutIt->end = I->end;
676  } else {
677  // Didn't merge. Move OutIt to the next segment,
678  ++OutIt;
679  OutIt->valno = nextValNo;
680  if (OutIt != I) {
681  OutIt->start = I->start;
682  OutIt->end = I->end;
683  }
684  }
685  }
686  // If we merge some segments, chop off the end.
687  ++OutIt;
688  segments.erase(OutIt, end());
689  }
690 
691  // Rewrite Other values before changing the VNInfo ids.
692  // This can leave Other in an invalid state because we're not coalescing
693  // touching segments that now have identical values. That's OK since Other is
694  // not supposed to be valid after calling join();
695  for (Segment &S : Other.segments)
696  S.valno = NewVNInfo[RHSValNoAssignments[S.valno->id]];
697 
698  // Update val# info. Renumber them and make sure they all belong to this
699  // LiveRange now. Also remove dead val#'s.
700  unsigned NumValNos = 0;
701  for (unsigned i = 0; i < NumNewVals; ++i) {
702  VNInfo *VNI = NewVNInfo[i];
703  if (VNI) {
704  if (NumValNos >= NumVals)
705  valnos.push_back(VNI);
706  else
707  valnos[NumValNos] = VNI;
708  VNI->id = NumValNos++; // Renumber val#.
709  }
710  }
711  if (NumNewVals < NumVals)
712  valnos.resize(NumNewVals); // shrinkify
713 
714  // Okay, now insert the RHS live segments into the LHS.
715  LiveRangeUpdater Updater(this);
716  for (Segment &S : Other.segments)
717  Updater.add(S);
718 }
719 
720 /// Merge all of the segments in RHS into this live range as the specified
721 /// value number. The segments in RHS are allowed to overlap with segments in
722 /// the current range, but only if the overlapping segments have the
723 /// specified value number.
725  VNInfo *LHSValNo) {
726  LiveRangeUpdater Updater(this);
727  for (const Segment &S : RHS.segments)
728  Updater.add(S.start, S.end, LHSValNo);
729 }
730 
731 /// MergeValueInAsValue - Merge all of the live segments of a specific val#
732 /// in RHS into this live range as the specified value number.
733 /// The segments in RHS are allowed to overlap with segments in the
734 /// current range, it will replace the value numbers of the overlaped
735 /// segments with the specified value number.
737  const VNInfo *RHSValNo,
738  VNInfo *LHSValNo) {
739  LiveRangeUpdater Updater(this);
740  for (const Segment &S : RHS.segments)
741  if (S.valno == RHSValNo)
742  Updater.add(S.start, S.end, LHSValNo);
743 }
744 
745 /// MergeValueNumberInto - This method is called when two value nubmers
746 /// are found to be equivalent. This eliminates V1, replacing all
747 /// segments with the V1 value number with the V2 value number. This can
748 /// cause merging of V1/V2 values numbers and compaction of the value space.
750  assert(V1 != V2 && "Identical value#'s are always equivalent!");
751 
752  // This code actually merges the (numerically) larger value number into the
753  // smaller value number, which is likely to allow us to compactify the value
754  // space. The only thing we have to be careful of is to preserve the
755  // instruction that defines the result value.
756 
757  // Make sure V2 is smaller than V1.
758  if (V1->id < V2->id) {
759  V1->copyFrom(*V2);
760  std::swap(V1, V2);
761  }
762 
763  // Merge V1 segments into V2.
764  for (iterator I = begin(); I != end(); ) {
765  iterator S = I++;
766  if (S->valno != V1) continue; // Not a V1 Segment.
767 
768  // Okay, we found a V1 live range. If it had a previous, touching, V2 live
769  // range, extend it.
770  if (S != begin()) {
771  iterator Prev = S-1;
772  if (Prev->valno == V2 && Prev->end == S->start) {
773  Prev->end = S->end;
774 
775  // Erase this live-range.
776  segments.erase(S);
777  I = Prev+1;
778  S = Prev;
779  }
780  }
781 
782  // Okay, now we have a V1 or V2 live range that is maximally merged forward.
783  // Ensure that it is a V2 live-range.
784  S->valno = V2;
785 
786  // If we can merge it into later V2 segments, do so now. We ignore any
787  // following V1 segments, as they will be merged in subsequent iterations
788  // of the loop.
789  if (I != end()) {
790  if (I->start == S->end && I->valno == V2) {
791  S->end = I->end;
792  segments.erase(I);
793  I = S+1;
794  }
795  }
796  }
797 
798  // Now that V1 is dead, remove it.
799  markValNoForDeletion(V1);
800 
801  return V2;
802 }
803 
805  assert(segmentSet != nullptr && "segment set must have been created");
806  assert(
807  segments.empty() &&
808  "segment set can be used only initially before switching to the array");
809  segments.append(segmentSet->begin(), segmentSet->end());
810  segmentSet = nullptr;
811  verify();
812 }
813 
815  ArrayRef<SlotIndex>::iterator SlotI = Slots.begin();
816  ArrayRef<SlotIndex>::iterator SlotE = Slots.end();
817 
818  // If there are no regmask slots, we have nothing to search.
819  if (SlotI == SlotE)
820  return false;
821 
822  // Start our search at the first segment that ends after the first slot.
823  const_iterator SegmentI = find(*SlotI);
824  const_iterator SegmentE = end();
825 
826  // If there are no segments that end after the first slot, we're done.
827  if (SegmentI == SegmentE)
828  return false;
829 
830  // Look for each slot in the live range.
831  for ( ; SlotI != SlotE; ++SlotI) {
832  // Go to the next segment that ends after the current slot.
833  // The slot may be within a hole in the range.
834  SegmentI = advanceTo(SegmentI, *SlotI);
835  if (SegmentI == SegmentE)
836  return false;
837 
838  // If this segment contains the slot, we're done.
839  if (SegmentI->contains(*SlotI))
840  return true;
841  // Otherwise, look for the next slot.
842  }
843 
844  // We didn't find a segment containing any of the slots.
845  return false;
846 }
847 
848 void LiveInterval::freeSubRange(SubRange *S) {
849  S->~SubRange();
850  // Memory was allocated with BumpPtr allocator and is not freed here.
851 }
852 
854  SubRange **NextPtr = &SubRanges;
855  SubRange *I = *NextPtr;
856  while (I != nullptr) {
857  if (!I->empty()) {
858  NextPtr = &I->Next;
859  I = *NextPtr;
860  continue;
861  }
862  // Skip empty subranges until we find the first nonempty one.
863  do {
864  SubRange *Next = I->Next;
865  freeSubRange(I);
866  I = Next;
867  } while (I != nullptr && I->empty());
868  *NextPtr = I;
869  }
870 }
871 
873  for (SubRange *I = SubRanges, *Next; I != nullptr; I = Next) {
874  Next = I->Next;
875  freeSubRange(I);
876  }
877  SubRanges = nullptr;
878 }
879 
880 /// For each VNI in \p SR, check whether or not that value defines part
881 /// of the mask describe by \p LaneMask and if not, remove that value
882 /// from \p SR.
884  LaneBitmask LaneMask,
885  const SlotIndexes &Indexes,
886  const TargetRegisterInfo &TRI) {
887  // Phys reg should not be tracked at subreg level.
888  // Same for noreg (Reg == 0).
889  if (!Register::isVirtualRegister(Reg) || !Reg)
890  return;
891  // Remove the values that don't define those lanes.
892  SmallVector<VNInfo *, 8> ToBeRemoved;
893  for (VNInfo *VNI : SR.valnos) {
894  if (VNI->isUnused())
895  continue;
896  // PHI definitions don't have MI attached, so there is nothing
897  // we can use to strip the VNI.
898  if (VNI->isPHIDef())
899  continue;
900  const MachineInstr *MI = Indexes.getInstructionFromIndex(VNI->def);
901  assert(MI && "Cannot find the definition of a value");
902  bool hasDef = false;
903  for (ConstMIBundleOperands MOI(*MI); MOI.isValid(); ++MOI) {
904  if (!MOI->isReg() || !MOI->isDef())
905  continue;
906  if (MOI->getReg() != Reg)
907  continue;
908  if ((TRI.getSubRegIndexLaneMask(MOI->getSubReg()) & LaneMask).none())
909  continue;
910  hasDef = true;
911  break;
912  }
913 
914  if (!hasDef)
915  ToBeRemoved.push_back(VNI);
916  }
917  for (VNInfo *VNI : ToBeRemoved)
918  SR.removeValNo(VNI);
919 
920  assert(!SR.empty() && "At least one value should be defined by this mask");
921 }
922 
925  std::function<void(LiveInterval::SubRange &)> Apply,
926  const SlotIndexes &Indexes, const TargetRegisterInfo &TRI) {
927  LaneBitmask ToApply = LaneMask;
928  for (SubRange &SR : subranges()) {
929  LaneBitmask SRMask = SR.LaneMask;
930  LaneBitmask Matching = SRMask & LaneMask;
931  if (Matching.none())
932  continue;
933 
934  SubRange *MatchingRange;
935  if (SRMask == Matching) {
936  // The subrange fits (it does not cover bits outside \p LaneMask).
937  MatchingRange = &SR;
938  } else {
939  // We have to split the subrange into a matching and non-matching part.
940  // Reduce lanemask of existing lane to non-matching part.
941  SR.LaneMask = SRMask & ~Matching;
942  // Create a new subrange for the matching part
943  MatchingRange = createSubRangeFrom(Allocator, Matching, SR);
944  // Now that the subrange is split in half, make sure we
945  // only keep in the subranges the VNIs that touch the related half.
946  stripValuesNotDefiningMask(reg, *MatchingRange, Matching, Indexes, TRI);
947  stripValuesNotDefiningMask(reg, SR, SR.LaneMask, Indexes, TRI);
948  }
949  Apply(*MatchingRange);
950  ToApply &= ~Matching;
951  }
952  // Create a new subrange if there are uncovered bits left.
953  if (ToApply.any()) {
954  SubRange *NewRange = createSubRange(Allocator, ToApply);
955  Apply(*NewRange);
956  }
957 }
958 
959 unsigned LiveInterval::getSize() const {
960  unsigned Sum = 0;
961  for (const Segment &S : segments)
962  Sum += S.start.distance(S.end);
963  return Sum;
964 }
965 
967  LaneBitmask LaneMask,
968  const MachineRegisterInfo &MRI,
969  const SlotIndexes &Indexes) const {
971  LaneBitmask VRegMask = MRI.getMaxLaneMaskForVReg(reg);
972  assert((VRegMask & LaneMask).any());
974  for (const MachineOperand &MO : MRI.def_operands(reg)) {
975  if (!MO.isUndef())
976  continue;
977  unsigned SubReg = MO.getSubReg();
978  assert(SubReg != 0 && "Undef should only be set on subreg defs");
979  LaneBitmask DefMask = TRI.getSubRegIndexLaneMask(SubReg);
980  LaneBitmask UndefMask = VRegMask & ~DefMask;
981  if ((UndefMask & LaneMask).any()) {
982  const MachineInstr &MI = *MO.getParent();
983  bool EarlyClobber = MO.isEarlyClobber();
984  SlotIndex Pos = Indexes.getInstructionIndex(MI).getRegSlot(EarlyClobber);
985  Undefs.push_back(Pos);
986  }
987  }
988 }
989 
991  return OS << '[' << S.start << ',' << S.end << ':' << S.valno->id << ')';
992 }
993 
994 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
996  dbgs() << *this << '\n';
997 }
998 #endif
999 
1001  if (empty())
1002  OS << "EMPTY";
1003  else {
1004  for (const Segment &S : segments) {
1005  OS << S;
1006  assert(S.valno == getValNumInfo(S.valno->id) && "Bad VNInfo");
1007  }
1008  }
1009 
1010  // Print value number info.
1011  if (getNumValNums()) {
1012  OS << " ";
1013  unsigned vnum = 0;
1014  for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e;
1015  ++i, ++vnum) {
1016  const VNInfo *vni = *i;
1017  if (vnum) OS << ' ';
1018  OS << vnum << '@';
1019  if (vni->isUnused()) {
1020  OS << 'x';
1021  } else {
1022  OS << vni->def;
1023  if (vni->isPHIDef())
1024  OS << "-phi";
1025  }
1026  }
1027  }
1028 }
1029 
1031  OS << " L" << PrintLaneMask(LaneMask) << ' '
1032  << static_cast<const LiveRange&>(*this);
1033 }
1034 
1036  OS << printReg(reg) << ' ';
1037  super::print(OS);
1038  // Print subranges
1039  for (const SubRange &SR : subranges())
1040  OS << SR;
1041  OS << " weight:" << weight;
1042 }
1043 
1044 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1046  dbgs() << *this << '\n';
1047 }
1048 
1050  dbgs() << *this << '\n';
1051 }
1052 
1054  dbgs() << *this << '\n';
1055 }
1056 #endif
1057 
1058 #ifndef NDEBUG
1059 void LiveRange::verify() const {
1060  for (const_iterator I = begin(), E = end(); I != E; ++I) {
1061  assert(I->start.isValid());
1062  assert(I->end.isValid());
1063  assert(I->start < I->end);
1064  assert(I->valno != nullptr);
1065  assert(I->valno->id < valnos.size());
1066  assert(I->valno == valnos[I->valno->id]);
1067  if (std::next(I) != E) {
1068  assert(I->end <= std::next(I)->start);
1069  if (I->end == std::next(I)->start)
1070  assert(I->valno != std::next(I)->valno);
1071  }
1072  }
1073 }
1074 
1076  super::verify();
1077 
1078  // Make sure SubRanges are fine and LaneMasks are disjunct.
1079  LaneBitmask Mask;
1080  LaneBitmask MaxMask = MRI != nullptr ? MRI->getMaxLaneMaskForVReg(reg)
1081  : LaneBitmask::getAll();
1082  for (const SubRange &SR : subranges()) {
1083  // Subrange lanemask should be disjunct to any previous subrange masks.
1084  assert((Mask & SR.LaneMask).none());
1085  Mask |= SR.LaneMask;
1086 
1087  // subrange mask should not contained in maximum lane mask for the vreg.
1088  assert((Mask & ~MaxMask).none());
1089  // empty subranges must be removed.
1090  assert(!SR.empty());
1091 
1092  SR.verify();
1093  // Main liverange should cover subrange.
1094  assert(covers(SR));
1095  }
1096 }
1097 #endif
1098 
1099 //===----------------------------------------------------------------------===//
1100 // LiveRangeUpdater class
1101 //===----------------------------------------------------------------------===//
1102 //
1103 // The LiveRangeUpdater class always maintains these invariants:
1104 //
1105 // - When LastStart is invalid, Spills is empty and the iterators are invalid.
1106 // This is the initial state, and the state created by flush().
1107 // In this state, isDirty() returns false.
1108 //
1109 // Otherwise, segments are kept in three separate areas:
1110 //
1111 // 1. [begin; WriteI) at the front of LR.
1112 // 2. [ReadI; end) at the back of LR.
1113 // 3. Spills.
1114 //
1115 // - LR.begin() <= WriteI <= ReadI <= LR.end().
1116 // - Segments in all three areas are fully ordered and coalesced.
1117 // - Segments in area 1 precede and can't coalesce with segments in area 2.
1118 // - Segments in Spills precede and can't coalesce with segments in area 2.
1119 // - No coalescing is possible between segments in Spills and segments in area
1120 // 1, and there are no overlapping segments.
1121 //
1122 // The segments in Spills are not ordered with respect to the segments in area
1123 // 1. They need to be merged.
1124 //
1125 // When they exist, Spills.back().start <= LastStart,
1126 // and WriteI[-1].start <= LastStart.
1127 
1128 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1130  if (!isDirty()) {
1131  if (LR)
1132  OS << "Clean updater: " << *LR << '\n';
1133  else
1134  OS << "Null updater.\n";
1135  return;
1136  }
1137  assert(LR && "Can't have null LR in dirty updater.");
1138  OS << " updater with gap = " << (ReadI - WriteI)
1139  << ", last start = " << LastStart
1140  << ":\n Area 1:";
1141  for (const auto &S : make_range(LR->begin(), WriteI))
1142  OS << ' ' << S;
1143  OS << "\n Spills:";
1144  for (unsigned I = 0, E = Spills.size(); I != E; ++I)
1145  OS << ' ' << Spills[I];
1146  OS << "\n Area 2:";
1147  for (const auto &S : make_range(ReadI, LR->end()))
1148  OS << ' ' << S;
1149  OS << '\n';
1150 }
1151 
1153  print(errs());
1154 }
1155 #endif
1156 
1157 // Determine if A and B should be coalesced.
1158 static inline bool coalescable(const LiveRange::Segment &A,
1159  const LiveRange::Segment &B) {
1160  assert(A.start <= B.start && "Unordered live segments.");
1161  if (A.end == B.start)
1162  return A.valno == B.valno;
1163  if (A.end < B.start)
1164  return false;
1165  assert(A.valno == B.valno && "Cannot overlap different values");
1166  return true;
1167 }
1168 
1170  assert(LR && "Cannot add to a null destination");
1171 
1172  // Fall back to the regular add method if the live range
1173  // is using the segment set instead of the segment vector.
1174  if (LR->segmentSet != nullptr) {
1175  LR->addSegmentToSet(Seg);
1176  return;
1177  }
1178 
1179  // Flush the state if Start moves backwards.
1180  if (!LastStart.isValid() || LastStart > Seg.start) {
1181  if (isDirty())
1182  flush();
1183  // This brings us to an uninitialized state. Reinitialize.
1184  assert(Spills.empty() && "Leftover spilled segments");
1185  WriteI = ReadI = LR->begin();
1186  }
1187 
1188  // Remember start for next time.
1189  LastStart = Seg.start;
1190 
1191  // Advance ReadI until it ends after Seg.start.
1192  LiveRange::iterator E = LR->end();
1193  if (ReadI != E && ReadI->end <= Seg.start) {
1194  // First try to close the gap between WriteI and ReadI with spills.
1195  if (ReadI != WriteI)
1196  mergeSpills();
1197  // Then advance ReadI.
1198  if (ReadI == WriteI)
1199  ReadI = WriteI = LR->find(Seg.start);
1200  else
1201  while (ReadI != E && ReadI->end <= Seg.start)
1202  *WriteI++ = *ReadI++;
1203  }
1204 
1205  assert(ReadI == E || ReadI->end > Seg.start);
1206 
1207  // Check if the ReadI segment begins early.
1208  if (ReadI != E && ReadI->start <= Seg.start) {
1209  assert(ReadI->valno == Seg.valno && "Cannot overlap different values");
1210  // Bail if Seg is completely contained in ReadI.
1211  if (ReadI->end >= Seg.end)
1212  return;
1213  // Coalesce into Seg.
1214  Seg.start = ReadI->start;
1215  ++ReadI;
1216  }
1217 
1218  // Coalesce as much as possible from ReadI into Seg.
1219  while (ReadI != E && coalescable(Seg, *ReadI)) {
1220  Seg.end = std::max(Seg.end, ReadI->end);
1221  ++ReadI;
1222  }
1223 
1224  // Try coalescing Spills.back() into Seg.
1225  if (!Spills.empty() && coalescable(Spills.back(), Seg)) {
1226  Seg.start = Spills.back().start;
1227  Seg.end = std::max(Spills.back().end, Seg.end);
1228  Spills.pop_back();
1229  }
1230 
1231  // Try coalescing Seg into WriteI[-1].
1232  if (WriteI != LR->begin() && coalescable(WriteI[-1], Seg)) {
1233  WriteI[-1].end = std::max(WriteI[-1].end, Seg.end);
1234  return;
1235  }
1236 
1237  // Seg doesn't coalesce with anything, and needs to be inserted somewhere.
1238  if (WriteI != ReadI) {
1239  *WriteI++ = Seg;
1240  return;
1241  }
1242 
1243  // Finally, append to LR or Spills.
1244  if (WriteI == E) {
1245  LR->segments.push_back(Seg);
1246  WriteI = ReadI = LR->end();
1247  } else
1248  Spills.push_back(Seg);
1249 }
1250 
1251 // Merge as many spilled segments as possible into the gap between WriteI
1252 // and ReadI. Advance WriteI to reflect the inserted instructions.
1253 void LiveRangeUpdater::mergeSpills() {
1254  // Perform a backwards merge of Spills and [SpillI;WriteI).
1255  size_t GapSize = ReadI - WriteI;
1256  size_t NumMoved = std::min(Spills.size(), GapSize);
1257  LiveRange::iterator Src = WriteI;
1258  LiveRange::iterator Dst = Src + NumMoved;
1259  LiveRange::iterator SpillSrc = Spills.end();
1260  LiveRange::iterator B = LR->begin();
1261 
1262  // This is the new WriteI position after merging spills.
1263  WriteI = Dst;
1264 
1265  // Now merge Src and Spills backwards.
1266  while (Src != Dst) {
1267  if (Src != B && Src[-1].start > SpillSrc[-1].start)
1268  *--Dst = *--Src;
1269  else
1270  *--Dst = *--SpillSrc;
1271  }
1272  assert(NumMoved == size_t(Spills.end() - SpillSrc));
1273  Spills.erase(SpillSrc, Spills.end());
1274 }
1275 
1277  if (!isDirty())
1278  return;
1279  // Clear the dirty state.
1280  LastStart = SlotIndex();
1281 
1282  assert(LR && "Cannot add to a null destination");
1283 
1284  // Nothing to merge?
1285  if (Spills.empty()) {
1286  LR->segments.erase(WriteI, ReadI);
1287  LR->verify();
1288  return;
1289  }
1290 
1291  // Resize the WriteI - ReadI gap to match Spills.
1292  size_t GapSize = ReadI - WriteI;
1293  if (GapSize < Spills.size()) {
1294  // The gap is too small. Make some room.
1295  size_t WritePos = WriteI - LR->begin();
1296  LR->segments.insert(ReadI, Spills.size() - GapSize, LiveRange::Segment());
1297  // This also invalidated ReadI, but it is recomputed below.
1298  WriteI = LR->begin() + WritePos;
1299  } else {
1300  // Shrink the gap if necessary.
1301  LR->segments.erase(WriteI + Spills.size(), ReadI);
1302  }
1303  ReadI = WriteI + Spills.size();
1304  mergeSpills();
1305  LR->verify();
1306 }
1307 
1309  // Create initial equivalence classes.
1310  EqClass.clear();
1311  EqClass.grow(LR.getNumValNums());
1312 
1313  const VNInfo *used = nullptr, *unused = nullptr;
1314 
1315  // Determine connections.
1316  for (const VNInfo *VNI : LR.valnos) {
1317  // Group all unused values into one class.
1318  if (VNI->isUnused()) {
1319  if (unused)
1320  EqClass.join(unused->id, VNI->id);
1321  unused = VNI;
1322  continue;
1323  }
1324  used = VNI;
1325  if (VNI->isPHIDef()) {
1326  const MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
1327  assert(MBB && "Phi-def has no defining MBB");
1328  // Connect to values live out of predecessors.
1330  PE = MBB->pred_end(); PI != PE; ++PI)
1331  if (const VNInfo *PVNI = LR.getVNInfoBefore(LIS.getMBBEndIdx(*PI)))
1332  EqClass.join(VNI->id, PVNI->id);
1333  } else {
1334  // Normal value defined by an instruction. Check for two-addr redef.
1335  // FIXME: This could be coincidental. Should we really check for a tied
1336  // operand constraint?
1337  // Note that VNI->def may be a use slot for an early clobber def.
1338  if (const VNInfo *UVNI = LR.getVNInfoBefore(VNI->def))
1339  EqClass.join(VNI->id, UVNI->id);
1340  }
1341  }
1342 
1343  // Lump all the unused values in with the last used value.
1344  if (used && unused)
1345  EqClass.join(used->id, unused->id);
1346 
1347  EqClass.compress();
1348  return EqClass.getNumClasses();
1349 }
1350 
1353  // Rewrite instructions.
1355  RE = MRI.reg_end(); RI != RE;) {
1356  MachineOperand &MO = *RI;
1357  MachineInstr *MI = RI->getParent();
1358  ++RI;
1359  const VNInfo *VNI;
1360  if (MI->isDebugValue()) {
1361  // DBG_VALUE instructions don't have slot indexes, so get the index of
1362  // the instruction before them. The value is defined there too.
1363  SlotIndex Idx = LIS.getSlotIndexes()->getIndexBefore(*MI);
1364  VNI = LI.Query(Idx).valueOut();
1365  } else {
1366  SlotIndex Idx = LIS.getInstructionIndex(*MI);
1367  LiveQueryResult LRQ = LI.Query(Idx);
1368  VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();
1369  }
1370  // In the case of an <undef> use that isn't tied to any def, VNI will be
1371  // NULL. If the use is tied to a def, VNI will be the defined value.
1372  if (!VNI)
1373  continue;
1374  if (unsigned EqClass = getEqClass(VNI))
1375  MO.setReg(LIV[EqClass-1]->reg);
1376  }
1377 
1378  // Distribute subregister liveranges.
1379  if (LI.hasSubRanges()) {
1380  unsigned NumComponents = EqClass.getNumClasses();
1381  SmallVector<unsigned, 8> VNIMapping;
1383  BumpPtrAllocator &Allocator = LIS.getVNInfoAllocator();
1384  for (LiveInterval::SubRange &SR : LI.subranges()) {
1385  // Create new subranges in the split intervals and construct a mapping
1386  // for the VNInfos in the subrange.
1387  unsigned NumValNos = SR.valnos.size();
1388  VNIMapping.clear();
1389  VNIMapping.reserve(NumValNos);
1390  SubRanges.clear();
1391  SubRanges.resize(NumComponents-1, nullptr);
1392  for (unsigned I = 0; I < NumValNos; ++I) {
1393  const VNInfo &VNI = *SR.valnos[I];
1394  unsigned ComponentNum;
1395  if (VNI.isUnused()) {
1396  ComponentNum = 0;
1397  } else {
1398  const VNInfo *MainRangeVNI = LI.getVNInfoAt(VNI.def);
1399  assert(MainRangeVNI != nullptr
1400  && "SubRange def must have corresponding main range def");
1401  ComponentNum = getEqClass(MainRangeVNI);
1402  if (ComponentNum > 0 && SubRanges[ComponentNum-1] == nullptr) {
1403  SubRanges[ComponentNum-1]
1404  = LIV[ComponentNum-1]->createSubRange(Allocator, SR.LaneMask);
1405  }
1406  }
1407  VNIMapping.push_back(ComponentNum);
1408  }
1409  DistributeRange(SR, SubRanges.data(), VNIMapping);
1410  }
1411  LI.removeEmptySubRanges();
1412  }
1413 
1414  // Distribute main liverange.
1415  DistributeRange(LI, LIV, EqClass);
1416 }
void add(LiveRange::Segment)
Add a segment to LR and coalesce when possible, just like LR.addSegment().
std::set< Segment > SegmentSet
Definition: LiveInterval.h:204
auto lower_bound(R &&Range, T &&Value) -> decltype(adl_begin(Range))
Provide wrappers to std::lower_bound which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1273
void RenumberValues()
RenumberValues - Renumber all values in order of appearance and remove unused values.
bool overlapsFrom(const LiveRange &Other, const_iterator StartPos) const
overlapsFrom - Return true if the intersection of the two live ranges is not empty.
bool empty() const
Definition: LiveInterval.h:369
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:77
const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:233
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:704
const_iterator begin(StringRef path, Style style=Style::native)
Get begin iterator over path.
Definition: Path.cpp:224
SlotIndex def
The index of the defining instruction.
Definition: LiveInterval.h:60
LaneBitmask getMaxLaneMaskForVReg(unsigned Reg) const
Returns a mask covering all bits that can appear in lane masks of subregisters of the virtual registe...
This class represents lattice values for constants.
Definition: AllocatorList.h:23
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:473
iterator begin() const
Definition: ArrayRef.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...
Segments::iterator iterator
Definition: LiveInterval.h:207
void push_back(const T &Elt)
Definition: SmallVector.h:211
bool isUndefIn(ArrayRef< SlotIndex > Undefs, SlotIndex Begin, SlotIndex End) const
Returns true if there is an explicit "undef" between Begin End.
Definition: LiveInterval.h:594
LiveInterval - This class represents the liveness of a register, or stack slot.
Definition: LiveInterval.h:675
This provides a very simple, boring adaptor for a begin and end iterator into a range type...
unsigned Reg
bool isDead() const
isDead - Returns true if this is a dead def kill slot.
Definition: SlotIndexes.h:236
bool isLiveAtIndexes(ArrayRef< SlotIndex > Slots) const
A live range for subregisters.
Definition: LiveInterval.h:682
This represents a simple continuous liveness interval for a value.
Definition: LiveInterval.h:161
unsigned const TargetRegisterInfo * TRI
Printable PrintLaneMask(LaneBitmask LaneMask)
Create Printable object to print LaneBitmasks on a raw_ostream.
Definition: LaneBitmask.h:93
void markUnused()
Mark this value as unused.
Definition: LiveInterval.h:83
Printable printReg(Register Reg, const TargetRegisterInfo *TRI=nullptr, unsigned SubIdx=0, const MachineRegisterInfo *MRI=nullptr)
Prints virtual and physical registers with or without a TRI instance.
std::vector< MachineBasicBlock * >::const_iterator const_pred_iterator
void reserve(size_type N)
Definition: SmallVector.h:369
VNInfo * valueOut() const
Return the value leaving the instruction, if any.
Definition: LiveInterval.h:122
VNInfo - Value Number Information.
Definition: LiveInterval.h:52
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:156
bool isUnused() const
Returns true if this value is unused.
Definition: LiveInterval.h:80
static bool isEarlierInstr(SlotIndex A, SlotIndex B)
isEarlierInstr - Return true if A refers to an instruction earlier than B.
Definition: SlotIndexes.h:203
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:226
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:259
A Use represents the edge between a Value definition and its users.
Definition: Use.h:55
iterator end()
Definition: LiveInterval.h:211
A helper class for register coalescers.
iterator_range< subrange_iterator > subranges()
Definition: LiveInterval.h:760
unsigned SubReg
Result of a LiveRange query.
Definition: LiveInterval.h:89
static constexpr LaneBitmask getAll()
Definition: LaneBitmask.h:83
SlotIndex getInstructionIndex(const MachineInstr &MI) const
Returns the base index for the given instruction.
Definition: SlotIndexes.h:390
bool hasSubRanges() const
Returns true if subregister liveness information is available.
Definition: LiveInterval.h:788
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. ...
bool isValid() const
isValid - Returns true until all the operands have been visited.
SlotIndexes pass.
Definition: SlotIndexes.h:314
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:254
iterator addSegment(Segment S)
Add the specified Segment to this range, merging segments as appropriate.
Segments segments
Definition: LiveInterval.h:198
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:32
SlotIndex getNextSlot() const
Returns the next slot in the index list.
Definition: SlotIndexes.h:269
void refineSubRanges(BumpPtrAllocator &Allocator, LaneBitmask LaneMask, std::function< void(LiveInterval::SubRange &)> Apply, const SlotIndexes &Indexes, const TargetRegisterInfo &TRI)
Refines the subranges to support LaneMask.
void setReg(Register Reg)
Change the register this operand corresponds to.
VNInfo * createDeadDef(SlotIndex Def, VNInfo::Allocator &VNIAlloc)
createDeadDef - Make sure the range has a value defined at Def.
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:69
VNInfo * valueIn() const
Return the value that is live-in to the instruction.
Definition: LiveInterval.h:104
LiveQueryResult Query(SlotIndex Idx) const
Query Liveness at Idx.
Definition: LiveInterval.h:528
VNInfo * getVNInfoAt(SlotIndex Idx) const
getVNInfoAt - Return the VNInfo that is live at Idx, or NULL.
Definition: LiveInterval.h:408
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:406
friend const_iterator end(StringRef path)
Get end iterator over path.
Definition: Path.cpp:233
const TargetRegisterInfo * getTargetRegisterInfo() const
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
static void stripValuesNotDefiningMask(unsigned Reg, LiveInterval::SubRange &SR, LaneBitmask LaneMask, const SlotIndexes &Indexes, const TargetRegisterInfo &TRI)
For each VNI in SR, check whether or not that value defines part of the mask describe by LaneMask and...
SubRange * createSubRange(BumpPtrAllocator &Allocator, LaneBitmask LaneMask)
Creates a new empty subregister live range.
Definition: LiveInterval.h:770
unsigned const MachineRegisterInfo * MRI
VNInfoList::const_iterator const_vni_iterator
Definition: LiveInterval.h:217
void print(raw_ostream &OS) const
Allocate memory in an ever growing pool, as if by bump-pointer.
Definition: Allocator.h:140
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:370
constexpr bool none() const
Definition: LaneBitmask.h:51
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.
auto remove_if(R &&Range, UnaryPredicate P) -> decltype(adl_begin(Range))
Provide wrappers to std::remove_if which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1217
iterator erase(const_iterator CI)
Definition: SmallVector.h:434
void print(raw_ostream &) const
TargetRegisterInfo base class - We assume that the target defines a static array of TargetRegisterDes...
size_t size() const
Definition: SmallVector.h:52
auto find(R &&Range, const T &Val) -> decltype(adl_begin(Range))
Provide wrappers to std::find which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1198
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().
constexpr bool empty(const T &RangeOrContainer)
Test whether RangeOrContainer is empty. Similar to C++17 std::empty.
Definition: STLExtras.h:209
unsigned id
The ID number of this value.
Definition: LiveInterval.h:57
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...
ConstMIBundleOperands - Iterate over all operands in a const bundle of machine instructions.
SmallPtrSet - This class implements a set which is optimized for holding SmallSize or less elements...
Definition: SmallPtrSet.h:417
auto size(R &&Range, typename std::enable_if< std::is_same< typename std::iterator_traits< decltype(Range.begin())>::iterator_category, std::random_access_iterator_tag >::value, void >::type *=nullptr) -> decltype(std::distance(Range.begin(), Range.end()))
Get the size of a range.
Definition: STLExtras.h:1158
static bool isSameInstr(SlotIndex A, SlotIndex B)
isSameInstr - Return true if A and B refer to the same instruction.
Definition: SlotIndexes.h:197
Segments::const_iterator const_iterator
Definition: LiveInterval.h:208
bool isDebugValue() const
MachineOperand class - Representation of each machine instruction operand.
iterator end() const
Definition: ArrayRef.h:137
reg_iterator reg_begin(unsigned RegNo) const
std::unique_ptr< SegmentSet > segmentSet
Definition: LiveInterval.h:205
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:940
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:416
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 ...
VNInfoList valnos
Definition: LiveInterval.h:199
iterator insert(iterator I, T &&Elt)
Definition: SmallVector.h:467
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:300
Representation of each machine instruction.
Definition: MachineInstr.h:64
pointer data()
Return a pointer to the vector&#39;s buffer, even if empty().
Definition: SmallVector.h:144
bool overlaps(const LiveRange &other) const
overlaps - Return true if the intersection of the two live ranges is not empty.
Definition: LiveInterval.h:435
SlotIndex getPrevSlot() const
Returns the previous slot in the index list.
Definition: SlotIndexes.h:289
#define I(x, y, z)
Definition: MD5.cpp:58
constexpr bool any() const
Definition: LaneBitmask.h:52
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:2045
iterator begin()
Definition: LiveInterval.h:210
Helper class for performant LiveRange bulk updates.
Definition: LiveInterval.h:898
VNInfo * getNextValue(SlotIndex def, VNInfo::Allocator &VNInfoAllocator)
getNextValue - Create a new value number and return it.
Definition: LiveInterval.h:318
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
SlotIndex beginIndex() const
beginIndex - Return the lowest numbered slot covered.
Definition: LiveInterval.h:372
std::pair< VNInfo *, bool > extendInBlock(ArrayRef< SlotIndex > Undefs, SlotIndex StartIdx, SlotIndex Kill)
Attempt to extend a value defined after StartIdx to include Use.
static bool isVirtualRegister(unsigned Reg)
Return true if the specified register number is in the virtual register namespace.
Definition: Register.h:69
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:80
void dump() const
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
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:134
static reg_iterator reg_end()
void print(raw_ostream &OS) const
SlotIndex - An opaque wrapper around machine indexes.
Definition: SlotIndexes.h:83
reg_begin/reg_end - Provide iteration support to walk over all definitions and uses of a register wit...
auto upper_bound(R &&Range, T &&Value) -> decltype(adl_begin(Range))
Provide wrappers to std::upper_bound which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1288
void resize(size_type N)
Definition: SmallVector.h:344