Line data Source code
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 :
21 : #include "llvm/CodeGen/LiveInterval.h"
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"
28 : #include "llvm/ADT/iterator_range.h"
29 : #include "llvm/CodeGen/LiveIntervals.h"
30 : #include "llvm/CodeGen/MachineBasicBlock.h"
31 : #include "llvm/CodeGen/MachineInstr.h"
32 : #include "llvm/CodeGen/MachineOperand.h"
33 : #include "llvm/CodeGen/MachineRegisterInfo.h"
34 : #include "llvm/CodeGen/SlotIndexes.h"
35 : #include "llvm/CodeGen/TargetRegisterInfo.h"
36 : #include "llvm/Config/llvm-config.h"
37 : #include "llvm/MC/LaneBitmask.h"
38 : #include "llvm/Support/Compiler.h"
39 : #include "llvm/Support/Debug.h"
40 : #include "llvm/Support/raw_ostream.h"
41 : #include <algorithm>
42 : #include <cassert>
43 : #include <cstddef>
44 : #include <iterator>
45 : #include <utility>
46 :
47 : using namespace llvm;
48 :
49 : namespace {
50 :
51 : //===----------------------------------------------------------------------===//
52 : // Implementation of various methods necessary for calculation of live ranges.
53 : // The implementation of the methods abstracts from the concrete type of the
54 : // segment collection.
55 : //
56 : // Implementation of the class follows the Template design pattern. The base
57 : // class contains generic algorithms that call collection-specific methods,
58 : // which are provided in concrete subclasses. In order to avoid virtual calls
59 : // these methods are provided by means of C++ template instantiation.
60 : // The base class calls the methods of the subclass through method impl(),
61 : // which casts 'this' pointer to the type of the subclass.
62 : //
63 : //===----------------------------------------------------------------------===//
64 :
65 : template <typename ImplT, typename IteratorT, typename CollectionT>
66 : class CalcLiveRangeUtilBase {
67 : protected:
68 : LiveRange *LR;
69 :
70 : protected:
71 16241403 : CalcLiveRangeUtilBase(LiveRange *LR) : LR(LR) {}
72 :
73 : public:
74 : using Segment = LiveRange::Segment;
75 : using iterator = IteratorT;
76 :
77 : /// A counterpart of LiveRange::createDeadDef: Make sure the range has a
78 : /// value defined at @p Def.
79 : /// If @p ForVNI is null, and there is no value defined at @p Def, a new
80 : /// value will be allocated using @p VNInfoAllocator.
81 : /// If @p ForVNI is null, the return value is the value defined at @p Def,
82 : /// either a pre-existing one, or the one newly created.
83 : /// If @p ForVNI is not null, then @p Def should be the location where
84 : /// @p ForVNI is defined. If the range does not have a value defined at
85 : /// @p Def, the value @p ForVNI will be used instead of allocating a new
86 : /// one. If the range already has a value defined at @p Def, it must be
87 : /// same as @p ForVNI. In either case, @p ForVNI will be the return value.
88 6027494 : VNInfo *createDeadDef(SlotIndex Def, VNInfo::Allocator *VNInfoAllocator,
89 : VNInfo *ForVNI) {
90 : assert(!Def.isDead() && "Cannot define a value at the dead slot");
91 : assert((!ForVNI || ForVNI->def == Def) &&
92 : "If ForVNI is specified, it must match Def");
93 9692081 : iterator I = impl().find(Def);
94 6027494 : if (I == segments().end()) {
95 4681184 : VNInfo *VNI = ForVNI ? ForVNI : LR->getNextValue(Def, *VNInfoAllocator);
96 8181647 : impl().insertAtEnd(Segment(Def, Def.getDeadSlot(), VNI));
97 4681184 : return VNI;
98 : }
99 :
100 : Segment *S = segmentAt(I);
101 1346310 : if (SlotIndex::isSameInstr(Def, S->start)) {
102 : assert((!ForVNI || ForVNI == S->valno) && "Value number mismatch");
103 : assert(S->valno->def == S->start && "Inconsistent existing value def");
104 :
105 : // It is possible to have both normal and early-clobber defs of the same
106 : // register on an instruction. It doesn't make a lot of sense, but it is
107 : // possible to specify in inline assembly.
108 : //
109 : // Just convert everything to early-clobber.
110 140448 : Def = std::min(Def, S->start);
111 140285 : if (Def != S->start)
112 0 : S->start = S->valno->def = Def;
113 140285 : return S->valno;
114 : }
115 : assert(SlotIndex::isEarlierInstr(Def, S->start) && "Already live at def");
116 1206025 : VNInfo *VNI = ForVNI ? ForVNI : LR->getNextValue(Def, *VNInfoAllocator);
117 1206025 : segments().insert(I, Segment(Def, Def.getDeadSlot(), VNI));
118 1206025 : return VNI;
119 : }
120 3664587 :
121 : VNInfo *extendInBlock(SlotIndex StartIdx, SlotIndex Use) {
122 : if (segments().empty())
123 : return nullptr;
124 : iterator I =
125 7329174 : impl().findInsertPos(Segment(Use.getPrevSlot(), Use, nullptr));
126 3664587 : if (I == segments().begin())
127 3500463 : return nullptr;
128 7000926 : --I;
129 3500463 : if (I->end <= StartIdx)
130 : return nullptr;
131 : if (I->end < Use)
132 : extendSegmentEndTo(I, Use);
133 164124 : return I->valno;
134 : }
135 :
136 : std::pair<VNInfo*,bool> extendInBlock(ArrayRef<SlotIndex> Undefs,
137 : SlotIndex StartIdx, SlotIndex Use) {
138 : if (segments().empty())
139 : return std::make_pair(nullptr, false);
140 : SlotIndex BeforeUse = Use.getPrevSlot();
141 : iterator I = impl().findInsertPos(Segment(BeforeUse, Use, nullptr));
142 126840 : if (I == segments().begin())
143 126680 : return std::make_pair(nullptr, LR->isUndefIn(Undefs, StartIdx, BeforeUse));
144 0 : --I;
145 126680 : if (I->end <= StartIdx)
146 : return std::make_pair(nullptr, LR->isUndefIn(Undefs, StartIdx, BeforeUse));
147 : if (I->end < Use) {
148 37444 : if (LR->isUndefIn(Undefs, I->end, BeforeUse))
149 37444 : return std::make_pair(nullptr, true);
150 37444 : extendSegmentEndTo(I, Use);
151 : }
152 2362907 : return std::make_pair(I->valno, false);
153 : }
154 :
155 : /// This method is used when we want to extend the segment specified
156 : /// by I to end at the specified endpoint. To do this, we should
157 2362907 : /// merge and eliminate all segments that this will overlap
158 2362907 : /// with. The iterator is not invalidated.
159 1180721 : void extendSegmentEndTo(iterator I, SlotIndex NewEnd) {
160 1180721 : assert(I != segments().end() && "Not a valid segment!");
161 1180721 : Segment *S = segmentAt(I);
162 : VNInfo *ValNo = I->valno;
163 :
164 : // Search for the first segment that we can't merge with.
165 1182186 : iterator MergeTo = std::next(I);
166 : for (; MergeTo != segments().end() && NewEnd >= MergeTo->end; ++MergeTo)
167 : assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
168 :
169 : // If NewEnd was in the middle of a segment, make sure to get its endpoint.
170 : S->end = std::max(NewEnd, std::prev(MergeTo)->end);
171 :
172 : // If the newly formed segment now touches the segment after it and if they
173 : // have the same value number, merge the two segments into one segment.
174 13608 : if (MergeTo != segments().end() && MergeTo->start <= I->end &&
175 13605 : MergeTo->valno == ValNo) {
176 0 : S->end = MergeTo->end;
177 13605 : ++MergeTo;
178 : }
179 :
180 1168581 : // Erase any dead segments.
181 1168581 : segments().erase(std::next(I), MergeTo);
182 1168581 : }
183 :
184 : /// This method is used when we want to extend the segment specified
185 303653 : /// by I to start at the specified endpoint. To do this, we should
186 303653 : /// merge and eliminate all segments that this will overlap with.
187 : iterator extendSegmentStartTo(iterator I, SlotIndex NewStart) {
188 303653 : assert(I != segments().end() && "Not a valid segment!");
189 : Segment *S = segmentAt(I);
190 303653 : VNInfo *ValNo = I->valno;
191 :
192 303608 : // Search for the first segment that we can't merge with.
193 303608 : iterator MergeTo = I;
194 : do {
195 108487 : if (MergeTo == segments().begin()) {
196 52687 : S->start = NewStart;
197 108487 : segments().erase(MergeTo, I);
198 : return I;
199 303653 : }
200 303653 : assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
201 : --MergeTo;
202 303653 : } while (NewStart <= MergeTo->start);
203 :
204 303653 : // If we start in the middle of another segment, just delete a range and
205 : // extend that segment.
206 303608 : if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) {
207 303608 : segmentAt(MergeTo)->end = S->end;
208 : } else {
209 108487 : // Otherwise, extend the segment right after.
210 52687 : ++MergeTo;
211 108487 : Segment *MergeToSeg = segmentAt(MergeTo);
212 : MergeToSeg->start = NewStart;
213 0 : MergeToSeg->end = S->end;
214 0 : }
215 :
216 0 : segments().erase(std::next(MergeTo), std::next(I));
217 : return MergeTo;
218 0 : }
219 :
220 : iterator addSegment(Segment S) {
221 0 : SlotIndex Start = S.start, End = S.end;
222 : iterator I = impl().findInsertPos(S);
223 0 :
224 0 : // If the inserted segment starts in the middle or right at the end of
225 0 : // another segment, just extend that segment to contain the segment of S.
226 : if (I != segments().begin()) {
227 : iterator B = std::prev(I);
228 8748210 : if (S.valno == B->valno) {
229 : if (B->start <= Start && B->end >= Start) {
230 8748210 : extendSegmentEndTo(B, End);
231 0 : return B;
232 : }
233 8748210 : } else {
234 8748210 : // Check to make sure that we are not overlapping two live segments with
235 3154 : // different valno's.
236 7198614 : assert(B->end <= Start &&
237 8745056 : "Cannot overlap two segments with differing ValID's"
238 1819440 : " (did you def the same reg twice in a MachineInstr?)");
239 6925616 : }
240 6423734 : }
241 2 :
242 6423732 : // Otherwise, if this segment ends in the middle of, or right next
243 : // to, another segment, merge it into that segment.
244 6925614 : if (I != segments().end()) {
245 : if (S.valno == I->valno) {
246 7201768 : if (I->start <= End) {
247 : I = extendSegmentStartTo(I, Start);
248 7201768 :
249 0 : // If S is a complete superset of a segment, we may need to grow its
250 : // endpoint as well.
251 7201768 : if (End > I->end)
252 7201768 : extendSegmentEndTo(I, End);
253 3154 : return I;
254 7198614 : }
255 7198614 : } else {
256 1819335 : // Check to make sure that we are not overlapping two live segments with
257 5379279 : // different valno's.
258 4882142 : assert(I->start >= End &&
259 2 : "Cannot overlap two segments with differing ValID's");
260 4882140 : }
261 : }
262 5379277 :
263 : // Otherwise, this is just a new segment that doesn't interact with
264 1546442 : // anything.
265 : // Insert it.
266 1546442 : return segments().insert(I, S);
267 0 : }
268 :
269 1546442 : private:
270 1546442 : ImplT &impl() { return *static_cast<ImplT *>(this); }
271 0 :
272 : CollectionT &segments() { return impl().segmentsColl(); }
273 1546442 :
274 105 : Segment *segmentAt(iterator I) { return const_cast<Segment *>(&(*I)); }
275 1546337 : };
276 1541592 :
277 0 : //===----------------------------------------------------------------------===//
278 1541592 : // Instantiation of the methods for calculation of live ranges
279 : // based on a segment vector.
280 1546337 : //===----------------------------------------------------------------------===//
281 :
282 : class CalcLiveRangeUtilVector;
283 : using CalcLiveRangeUtilVectorBase =
284 : CalcLiveRangeUtilBase<CalcLiveRangeUtilVector, LiveRange::iterator,
285 : LiveRange::Segments>;
286 :
287 7190107 : class CalcLiveRangeUtilVector : public CalcLiveRangeUtilVectorBase {
288 : public:
289 : CalcLiveRangeUtilVector(LiveRange *LR) : CalcLiveRangeUtilVectorBase(LR) {}
290 7190107 :
291 : private:
292 : friend CalcLiveRangeUtilVectorBase;
293 1541644 :
294 7190107 : LiveRange::Segments &segmentsColl() { return LR->segments; }
295 :
296 : void insertAtEnd(const Segment &S) { LR->segments.push_back(S); }
297 :
298 7190107 : iterator find(SlotIndex Pos) { return LR->find(Pos); }
299 :
300 : iterator findInsertPos(Segment S) {
301 : return std::upper_bound(LR->begin(), LR->end(), S.start);
302 7190107 : }
303 488891 : };
304 56862 :
305 56861 : //===----------------------------------------------------------------------===//
306 : // Instantiation of the methods for calculation of live ranges
307 : // based on a segment set.
308 : //===----------------------------------------------------------------------===//
309 1541644 :
310 7190107 : class CalcLiveRangeUtilSet;
311 5648463 : using CalcLiveRangeUtilSetBase =
312 : CalcLiveRangeUtilBase<CalcLiveRangeUtilSet, LiveRange::SegmentSet::iterator,
313 : LiveRange::SegmentSet>;
314 5648463 :
315 : class CalcLiveRangeUtilSet : public CalcLiveRangeUtilSetBase {
316 : public:
317 : CalcLiveRangeUtilSet(LiveRange *LR) : CalcLiveRangeUtilSetBase(LR) {}
318 5648463 :
319 : private:
320 : friend CalcLiveRangeUtilSetBase;
321 :
322 5648463 : LiveRange::SegmentSet &segmentsColl() { return *LR->segmentSet; }
323 :
324 : void insertAtEnd(const Segment &S) {
325 : LR->segmentSet->insert(LR->segmentSet->end(), S);
326 5648463 : }
327 447516 :
328 56861 : iterator find(SlotIndex Pos) {
329 56861 : iterator I =
330 : LR->segmentSet->upper_bound(Segment(Pos, Pos.getNextSlot(), nullptr));
331 : if (I == LR->segmentSet->begin())
332 : return I;
333 : iterator PrevI = std::prev(I);
334 5648463 : if (Pos < (*PrevI).end)
335 1541644 : return PrevI;
336 : return I;
337 : }
338 1541644 :
339 : iterator findInsertPos(Segment S) {
340 : iterator I = LR->segmentSet->upper_bound(S);
341 1541644 : if (I != LR->segmentSet->end() && !(S.start < *I))
342 1541644 : ++I;
343 : return I;
344 : }
345 : };
346 1541644 :
347 : } // end anonymous namespace
348 :
349 : //===----------------------------------------------------------------------===//
350 1541644 : // LiveRange methods
351 41375 : //===----------------------------------------------------------------------===//
352 1 :
353 : LiveRange::iterator LiveRange::find(SlotIndex Pos) {
354 : // This algorithm is basically std::upper_bound.
355 : // Unfortunately, std::upper_bound cannot be used with mixed types until we
356 : // adopt C++0x. Many libraries can do it, but not all.
357 1541644 : if (empty() || Pos >= endIndex())
358 1541644 : return end();
359 : iterator I = begin();
360 : size_t Len = size();
361 : do {
362 : size_t Mid = Len >> 1;
363 97778 : if (Pos < I[Mid].end) {
364 : Len = Mid;
365 : } else {
366 97778 : I += Mid + 1;
367 : Len -= Mid + 1;
368 : }
369 : } while (Len);
370 : return I;
371 97778 : }
372 12 :
373 : VNInfo *LiveRange::createDeadDef(SlotIndex Def, VNInfo::Allocator &VNIAlloc) {
374 12 : // Use the segment set, if it is available.
375 : if (segmentSet != nullptr)
376 : return CalcLiveRangeUtilSet(this).createDeadDef(Def, &VNIAlloc, nullptr);
377 97766 : // Otherwise use the segment vector.
378 97766 : return CalcLiveRangeUtilVector(this).createDeadDef(Def, &VNIAlloc, nullptr);
379 : }
380 :
381 : VNInfo *LiveRange::createDeadDef(VNInfo *VNI) {
382 97766 : // Use the segment set, if it is available.
383 0 : if (segmentSet != nullptr)
384 : return CalcLiveRangeUtilSet(this).createDeadDef(VNI->def, nullptr, VNI);
385 : // Otherwise use the segment vector.
386 : return CalcLiveRangeUtilVector(this).createDeadDef(VNI->def, nullptr, VNI);
387 : }
388 97766 :
389 97766 : // overlaps - Return true if the intersection of the two live ranges is
390 : // not empty.
391 : //
392 0 : // An example for overlaps():
393 97766 : //
394 : // 0: A = ...
395 97778 : // 4: B = ...
396 : // 8: C = A + B ;; last use of A
397 : //
398 97778 : // The live ranges should look like:
399 : //
400 : // A = [3, 11)
401 : // B = [7, x)
402 : // C = [11, y)
403 97778 : //
404 12 : // A->overlaps(C) should return false since we want to be able to join
405 : // A and C.
406 12 : //
407 : bool LiveRange::overlapsFrom(const LiveRange& other,
408 : const_iterator StartPos) const {
409 97766 : assert(!empty() && "empty range");
410 97766 : const_iterator i = begin();
411 : const_iterator ie = end();
412 : const_iterator j = StartPos;
413 : const_iterator je = other.end();
414 97766 :
415 0 : assert((StartPos->start <= i->start || StartPos == other.begin()) &&
416 : StartPos != other.end() && "Bogus start position hint!");
417 :
418 : if (i->start < j->start) {
419 : i = std::upper_bound(i, ie, j->start);
420 97766 : if (i != begin()) --i;
421 97766 : } else if (j->start < i->start) {
422 : ++StartPos;
423 : if (StartPos != other.end() && StartPos->start <= i->start) {
424 : assert(StartPos < other.end() && i < end());
425 97766 : j = std::upper_bound(j, je, i->start);
426 : if (j != other.begin()) --j;
427 0 : }
428 : } else {
429 : return true;
430 0 : }
431 :
432 : if (j == je) return false;
433 :
434 : while (i != ie) {
435 0 : if (i->start > j->start) {
436 0 : std::swap(i, j);
437 : std::swap(ie, je);
438 0 : }
439 :
440 : if (i->end > j->start)
441 : return true;
442 0 : ++i;
443 : }
444 :
445 : return false;
446 0 : }
447 0 :
448 : bool LiveRange::overlaps(const LiveRange &Other, const CoalescerPair &CP,
449 : const SlotIndexes &Indexes) const {
450 : assert(!empty() && "empty range");
451 : if (Other.empty())
452 0 : return false;
453 0 :
454 : // Use binary searches to find initial positions.
455 : const_iterator I = find(Other.beginIndex());
456 0 : const_iterator IE = end();
457 0 : if (I == IE)
458 : return false;
459 : const_iterator J = Other.find(I->start);
460 1162046 : const_iterator JE = Other.end();
461 1162046 : if (J == JE)
462 1162046 : return false;
463 :
464 : while (true) {
465 : // J has just been advanced to satisfy:
466 1162046 : assert(J->end >= I->start);
467 105 : // Check for an overlap.
468 1043211 : if (J->start < I->end) {
469 906771 : // I and J are overlapping. Find the later start.
470 713688 : SlotIndex Def = std::max(I->start, J->start);
471 713688 : // Allow the overlap if Def is a coalescable copy.
472 : if (Def.isBlock() ||
473 : !CP.isCoalescable(Indexes.getInstructionFromIndex(Def)))
474 : return true;
475 : }
476 : // Advance the iterator that ends first to check for more overlaps.
477 : if (J->end > I->end) {
478 : std::swap(I, J);
479 : std::swap(IE, JE);
480 : }
481 : // Advance J until J->end >= I->start.
482 : do
483 : if (++J == JE)
484 448358 : return false;
485 187802 : while (J->end < I->start);
486 152272 : }
487 97778 : }
488 :
489 : /// overlaps - Return true if the live range overlaps an interval specified
490 : /// by [Start, End).
491 97778 : bool LiveRange::overlaps(SlotIndex Start, SlotIndex End) const {
492 0 : assert(Start < End && "Invalid range");
493 97778 : const_iterator I = std::lower_bound(begin(), end(), End);
494 : return I != begin() && (--I)->end > Start;
495 : }
496 :
497 : bool LiveRange::covers(const LiveRange &Other) const {
498 : if (empty())
499 : return Other.empty();
500 :
501 : const_iterator I = begin();
502 : for (const Segment &O : Other.segments) {
503 : I = advanceTo(I, O.start);
504 : if (I == end() || I->start > O.start)
505 : return false;
506 350580 :
507 : // Check adjacent live segments and see if we can get behind O.end.
508 1161941 : while (I->end < O.end) {
509 1161941 : const_iterator Last = I;
510 1161941 : // Get next segment and abort if it was not adjacent.
511 : ++I;
512 : if (I == end() || Last->end != I->start)
513 : return false;
514 1161941 : }
515 : }
516 1043106 : return true;
517 906705 : }
518 713636 :
519 713636 : /// ValNo is dead, remove it. If it is the largest value number, just nuke it
520 : /// (and any other deleted values neighboring it), otherwise mark it as ~1U so
521 : /// it can be nuked later.
522 : void LiveRange::markValNoForDeletion(VNInfo *ValNo) {
523 : if (ValNo->id == getNumValNums()-1) {
524 : do {
525 : valnos.pop_back();
526 : } while (!valnos.empty() && valnos.back()->isUnused());
527 : } else {
528 : ValNo->markUnused();
529 : }
530 : }
531 :
532 448305 : /// RenumberValues - Renumber all values in order of appearance and delete the
533 187757 : /// remaining unused values.
534 152272 : void LiveRange::RenumberValues() {
535 97778 : SmallPtrSet<VNInfo*, 8> Seen;
536 : valnos.clear();
537 : for (const Segment &S : segments) {
538 : VNInfo *VNI = S.valno;
539 97778 : if (!Seen.insert(VNI).second)
540 0 : continue;
541 97778 : assert(!VNI->isUnused() && "Unused valno used by live segment");
542 : VNI->id = (unsigned)valnos.size();
543 : valnos.push_back(VNI);
544 : }
545 : }
546 :
547 : void LiveRange::addSegmentToSet(Segment S) {
548 : CalcLiveRangeUtilSet(this).addSegment(S);
549 : }
550 :
551 : LiveRange::iterator LiveRange::addSegment(Segment S) {
552 : // Use the segment set, if it is available.
553 : if (segmentSet != nullptr) {
554 350527 : addSegmentToSet(S);
555 : return end();
556 105 : }
557 105 : // Otherwise use the segment vector.
558 105 : return CalcLiveRangeUtilVector(this).addSegment(S);
559 : }
560 :
561 : void LiveRange::append(const Segment S) {
562 105 : // Check that the segment belongs to the back of the list.
563 105 : assert(segments.empty() || segments.back().end <= S.start);
564 105 : segments.push_back(S);
565 66 : }
566 52 :
567 52 : std::pair<VNInfo*,bool> LiveRange::extendInBlock(ArrayRef<SlotIndex> Undefs,
568 : SlotIndex StartIdx, SlotIndex Kill) {
569 : // Use the segment set, if it is available.
570 : if (segmentSet != nullptr)
571 : return CalcLiveRangeUtilSet(this).extendInBlock(Undefs, StartIdx, Kill);
572 : // Otherwise use the segment vector.
573 : return CalcLiveRangeUtilVector(this).extendInBlock(Undefs, StartIdx, Kill);
574 : }
575 :
576 : VNInfo *LiveRange::extendInBlock(SlotIndex StartIdx, SlotIndex Kill) {
577 : // Use the segment set, if it is available.
578 : if (segmentSet != nullptr)
579 : return CalcLiveRangeUtilSet(this).extendInBlock(StartIdx, Kill);
580 53 : // Otherwise use the segment vector.
581 45 : return CalcLiveRangeUtilVector(this).extendInBlock(StartIdx, Kill);
582 0 : }
583 0 :
584 : /// Remove the specified segment from this range. Note that the segment must
585 : /// be in a single Segment in its entirety.
586 : void LiveRange::removeSegment(SlotIndex Start, SlotIndex End,
587 0 : bool RemoveDeadValNo) {
588 0 : // Find the Segment containing this span.
589 0 : iterator I = find(Start);
590 : assert(I != end() && "Segment is not in range!");
591 : assert(I->containsInterval(Start, End)
592 : && "Segment is not entirely in range!");
593 :
594 : // If the span we are removing is at the start of the Segment, adjust it.
595 : VNInfo *ValNo = I->valno;
596 : if (I->start == Start) {
597 : if (I->end == End) {
598 : if (RemoveDeadValNo) {
599 : // Check if val# is dead.
600 : bool isDead = true;
601 : for (const_iterator II = begin(), EE = end(); II != EE; ++II)
602 53 : if (II != I && II->valno == ValNo) {
603 : isDead = false;
604 : break;
605 : }
606 : if (isDead) {
607 : // Now that ValNo is dead, remove it.
608 33243631 : markValNoForDeletion(ValNo);
609 : }
610 0 : }
611 :
612 : segments.erase(I); // Removed the whole Segment.
613 : } else
614 : I->start = End;
615 : return;
616 : }
617 :
618 : // Otherwise if the span we are removing is at the end of the Segment,
619 : // adjust the other way.
620 : if (I->end == End) {
621 : I->end = Start;
622 : return;
623 : }
624 :
625 : // Otherwise, we are splitting the Segment into two pieces.
626 : SlotIndex OldEnd = I->end;
627 : I->end = Start; // Trim the old segment.
628 :
629 : // Insert the new one.
630 0 : segments.insert(std::next(I), Segment(End, OldEnd, ValNo));
631 : }
632 3500463 :
633 : /// removeValNo - Remove all the segments defined by the specified value#.
634 3664587 : /// Also remove the value# from value# list.
635 : void LiveRange::removeValNo(VNInfo *ValNo) {
636 0 : if (empty()) return;
637 0 : segments.erase(remove_if(*this, [ValNo](const Segment &S) {
638 : return S.valno == ValNo;
639 : }), end());
640 : // Now that ValNo is dead, remove it.
641 : markValNoForDeletion(ValNo);
642 : }
643 :
644 : void LiveRange::join(LiveRange &Other,
645 : const int *LHSValNoAssignments,
646 : const int *RHSValNoAssignments,
647 : SmallVectorImpl<VNInfo *> &NewVNInfo) {
648 : verify();
649 :
650 : // Determine if any of our values are mapped. This is uncommon, so we want
651 : // to avoid the range scan if not.
652 : bool MustMapCurValNos = false;
653 : unsigned NumVals = getNumValNums();
654 : unsigned NumNewVals = NewVNInfo.size();
655 : for (unsigned i = 0; i != NumVals; ++i) {
656 : unsigned LHSValID = LHSValNoAssignments[i];
657 : if (i != LHSValID ||
658 0 : (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) {
659 : MustMapCurValNos = true;
660 0 : break;
661 0 : }
662 0 : }
663 :
664 0 : // If we have to apply a mapping to our base range assignment, rewrite it now.
665 : if (MustMapCurValNos && !empty()) {
666 0 : // Map the first live range.
667 0 :
668 0 : iterator OutIt = begin();
669 0 : OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]];
670 0 : for (iterator I = std::next(OutIt), E = end(); I != E; ++I) {
671 0 : VNInfo* nextValNo = NewVNInfo[LHSValNoAssignments[I->valno->id]];
672 0 : assert(nextValNo && "Huh?");
673 :
674 : // If this live range has the same value # as its immediate predecessor,
675 0 : // and if they are neighbors, remove one Segment. This happens when we
676 0 : // have [0,4:0)[4,7:1) and map 0/1 onto the same value #.
677 0 : if (OutIt->valno == nextValNo && OutIt->end == I->start) {
678 : OutIt->end = I->end;
679 0 : } else {
680 : // Didn't merge. Move OutIt to the next segment,
681 : ++OutIt;
682 : OutIt->valno = nextValNo;
683 : if (OutIt != I) {
684 : OutIt->start = I->start;
685 : OutIt->end = I->end;
686 : }
687 : }
688 : }
689 82617600 : // If we merge some segments, chop off the end.
690 : ++OutIt;
691 : segments.erase(OutIt, end());
692 : }
693 82617600 :
694 12959946 : // Rewrite Other values before changing the VNInfo ids.
695 : // This can leave Other in an invalid state because we're not coalescing
696 : // touching segments that now have identical values. That's OK since Other is
697 : // not supposed to be valid after calling join();
698 107952518 : for (Segment &S : Other.segments)
699 215905036 : S.valno = NewVNInfo[RHSValNoAssignments[S.valno->id]];
700 :
701 : // Update val# info. Renumber them and make sure they all belong to this
702 18935611 : // LiveRange now. Also remove dead val#'s.
703 18935611 : unsigned NumValNos = 0;
704 : for (unsigned i = 0; i < NumNewVals; ++i) {
705 107952518 : VNInfo *VNI = NewVNInfo[i];
706 : if (VNI) {
707 : if (NumValNos >= NumVals)
708 : valnos.push_back(VNI);
709 5962389 : else
710 : valnos[NumValNos] = VNI;
711 5962389 : VNI->id = NumValNos++; // Renumber val#.
712 2362907 : }
713 : }
714 3599482 : if (NumNewVals < NumVals)
715 : valnos.resize(NumNewVals); // shrinkify
716 :
717 65105 : // Okay, now insert the RHS live segments into the LHS.
718 : LiveRangeUpdater Updater(this);
719 65105 : for (Segment &S : Other.segments)
720 0 : Updater.add(S);
721 : }
722 65105 :
723 : /// Merge all of the segments in RHS into this live range as the specified
724 : /// value number. The segments in RHS are allowed to overlap with segments in
725 : /// the current range, but only if the overlapping segments have the
726 : /// specified value number.
727 : void LiveRange::MergeSegmentsInAsValue(const LiveRange &RHS,
728 : VNInfo *LHSValNo) {
729 : LiveRangeUpdater Updater(this);
730 : for (const Segment &S : RHS.segments)
731 : Updater.add(S.start, S.end, LHSValNo);
732 : }
733 :
734 : /// MergeValueInAsValue - Merge all of the live segments of a specific val#
735 : /// in RHS into this live range as the specified value number.
736 : /// The segments in RHS are allowed to overlap with segments in the
737 : /// current range, it will replace the value numbers of the overlaped
738 : /// segments with the specified value number.
739 : void LiveRange::MergeValueInAsValue(const LiveRange &RHS,
740 : const VNInfo *RHSValNo,
741 : VNInfo *LHSValNo) {
742 : LiveRangeUpdater Updater(this);
743 514916 : for (const Segment &S : RHS.segments)
744 : if (S.valno == RHSValNo)
745 : Updater.add(S.start, S.end, LHSValNo);
746 : }
747 :
748 : /// MergeValueNumberInto - This method is called when two value nubmers
749 : /// are found to be equivalent. This eliminates V1, replacing all
750 : /// segments with the V1 value number with the V2 value number. This can
751 : /// cause merging of V1/V2 values numbers and compaction of the value space.
752 : VNInfo *LiveRange::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) {
753 : assert(V1 != V2 && "Identical value#'s are always equivalent!");
754 514916 :
755 248401 : // This code actually merges the (numerically) larger value number into the
756 248401 : // smaller value number, which is likely to allow us to compactify the value
757 266515 : // space. The only thing we have to be careful of is to preserve the
758 265745 : // instruction that defines the result value.
759 265745 :
760 : // Make sure V2 is smaller than V1.
761 149494 : if (V1->id < V2->id) {
762 149494 : V1->copyFrom(*V2);
763 : std::swap(V1, V2);
764 : }
765 :
766 : // Merge V1 segments into V2.
767 : for (iterator I = begin(); I != end(); ) {
768 514146 : iterator S = I++;
769 : if (S->valno != V1) continue; // Not a V1 Segment.
770 799968 :
771 645013 : // Okay, we found a V1 live range. If it had a previous, touching, V2 live
772 : // range, extend it.
773 : if (S != begin()) {
774 : iterator Prev = S-1;
775 : if (Prev->valno == V2 && Prev->end == S->start) {
776 645013 : Prev->end = S->end;
777 :
778 285822 : // Erase this live-range.
779 : segments.erase(S);
780 : I = Prev+1;
781 : S = Prev;
782 : }
783 : }
784 10611357 :
785 : // Okay, now we have a V1 or V2 live range that is maximally merged forward.
786 : // Ensure that it is a V2 live-range.
787 10611357 : S->valno = V2;
788 :
789 : // If we can merge it into later V2 segments, do so now. We ignore any
790 : // following V1 segments, as they will be merged in subsequent iterations
791 3054757 : // of the loop.
792 : if (I != end()) {
793 3054757 : if (I->start == S->end && I->valno == V2) {
794 : S->end = I->end;
795 2702369 : segments.erase(I);
796 : I = S+1;
797 2702369 : }
798 : }
799 : }
800 :
801 : // Now that V1 is dead, remove it.
802 : markValNoForDeletion(V1);
803 :
804 2285043 : return V2;
805 : }
806 1690560 :
807 : void LiveRange::flushSegmentSet() {
808 1844608 : assert(segmentSet != nullptr && "segment set must have been created");
809 919143 : assert(
810 : segments.empty() &&
811 : "segment set can be used only initially before switching to the array");
812 : segments.append(segmentSet->begin(), segmentSet->end());
813 1527414 : segmentSet = nullptr;
814 : verify();
815 : }
816 :
817 : bool LiveRange::isLiveAtIndexes(ArrayRef<SlotIndex> Slots) const {
818 : ArrayRef<SlotIndex>::iterator SlotI = Slots.begin();
819 2450612 : ArrayRef<SlotIndex>::iterator SlotE = Slots.end();
820 :
821 1442570 : // If there are no regmask slots, we have nothing to search.
822 : if (SlotI == SlotE)
823 : return false;
824 :
825 : // Start our search at the first segment that ends after the first slot.
826 : const_iterator SegmentI = find(*SlotI);
827 54238 : const_iterator SegmentE = end();
828 :
829 : // If there are no segments that end after the first slot, we're done.
830 54238 : if (SegmentI == SegmentE)
831 : return false;
832 :
833 1026492 : // Look for each slot in the live range.
834 1026492 : for ( ; SlotI != SlotE; ++SlotI) {
835 0 : // Go to the next segment that ends after the current slot.
836 : // The slot may be within a hole in the range.
837 : SegmentI = advanceTo(SegmentI, *SlotI);
838 2088632 : if (SegmentI == SegmentE)
839 1062140 : return false;
840 1062140 :
841 : // If this segment contains the slot, we're done.
842 : if (SegmentI->contains(*SlotI))
843 : return true;
844 1891100 : // Otherwise, look for the next slot.
845 : }
846 :
847 828960 : // We didn't find a segment containing any of the slots.
848 828960 : return false;
849 : }
850 :
851 : void LiveInterval::freeSubRange(SubRange *S) {
852 : S->~SubRange();
853 : // Memory was allocated with BumpPtr allocator and is not freed here.
854 : }
855 :
856 : void LiveInterval::removeEmptySubRanges() {
857 : SubRange **NextPtr = &SubRanges;
858 78253 : SubRange *I = *NextPtr;
859 156506 : while (I != nullptr) {
860 : if (!I->empty()) {
861 : NextPtr = &I->Next;
862 71520 : I = *NextPtr;
863 : continue;
864 : }
865 : // Skip empty subranges until we find the first nonempty one.
866 78253 : do {
867 : SubRange *Next = I->Next;
868 : freeSubRange(I);
869 : I = Next;
870 61634 : } while (I != nullptr && I->empty());
871 : *NextPtr = I;
872 : }
873 236808 : }
874 175174 :
875 175174 : void LiveInterval::clearSubRanges() {
876 69039 : for (SubRange *I = SubRanges, *Next; I != nullptr; I = Next) {
877 : Next = I->Next;
878 106135 : freeSubRange(I);
879 106135 : }
880 : SubRanges = nullptr;
881 61634 : }
882 :
883 105 : void LiveInterval::refineSubRanges(BumpPtrAllocator &Allocator,
884 105 : LaneBitmask LaneMask, std::function<void(LiveInterval::SubRange&)> Apply) {
885 105 : LaneBitmask ToApply = LaneMask;
886 : for (SubRange &SR : subranges()) {
887 1161953 : LaneBitmask SRMask = SR.LaneMask;
888 : LaneBitmask Matching = SRMask & LaneMask;
889 1161953 : if (Matching.none())
890 12 : continue;
891 12 :
892 : SubRange *MatchingRange;
893 : if (SRMask == Matching) {
894 1161941 : // The subrange fits (it does not cover bits outside \p LaneMask).
895 : MatchingRange = &SR;
896 : } else {
897 0 : // We have to split the subrange into a matching and non-matching part.
898 : // Reduce lanemask of existing lane to non-matching part.
899 : SR.LaneMask = SRMask & ~Matching;
900 0 : // Create a new subrange for the matching part
901 0 : MatchingRange = createSubRangeFrom(Allocator, Matching, SR);
902 : }
903 8748210 : Apply(*MatchingRange);
904 : ToApply &= ~Matching;
905 : }
906 8748210 : // Create a new subrange if there are uncovered bits left.
907 1546442 : if (ToApply.any()) {
908 : SubRange *NewRange = createSubRange(Allocator, ToApply);
909 7201768 : Apply(*NewRange);
910 : }
911 : }
912 303653 :
913 : unsigned LiveInterval::getSize() const {
914 303653 : unsigned Sum = 0;
915 0 : for (const Segment &S : segments)
916 : Sum += S.start.distance(S.end);
917 303653 : return Sum;
918 : }
919 :
920 : void LiveInterval::computeSubRangeUndefs(SmallVectorImpl<SlotIndex> &Undefs,
921 : LaneBitmask LaneMask,
922 119089 : const MachineRegisterInfo &MRI,
923 : const SlotIndexes &Indexes) const {
924 : assert(TargetRegisterInfo::isVirtualRegister(reg));
925 119089 : LaneBitmask VRegMask = MRI.getMaxLaneMaskForVReg(reg);
926 : assert((VRegMask & LaneMask).any());
927 : const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
928 : for (const MachineOperand &MO : MRI.def_operands(reg)) {
929 : if (!MO.isUndef())
930 : continue;
931 119089 : unsigned SubReg = MO.getSubReg();
932 119089 : assert(SubReg != 0 && "Undef should only be set on subreg defs");
933 44157 : LaneBitmask DefMask = TRI.getSubRegIndexLaneMask(SubReg);
934 43091 : LaneBitmask UndefMask = VRegMask & ~DefMask;
935 : if ((UndefMask & LaneMask).any()) {
936 : const MachineInstr &MI = *MO.getParent();
937 186 : bool EarlyClobber = MO.isEarlyClobber();
938 146 : SlotIndex Pos = Indexes.getInstructionIndex(MI).getRegSlot(EarlyClobber);
939 : Undefs.push_back(Pos);
940 : }
941 : }
942 40 : }
943 :
944 40 : raw_ostream& llvm::operator<<(raw_ostream& OS, const LiveRange::Segment &S) {
945 : return OS << '[' << S.start << ',' << S.end << ':' << S.valno->id << ')';
946 : }
947 :
948 : #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
949 : LLVM_DUMP_METHOD void LiveRange::Segment::dump() const {
950 1066 : dbgs() << *this << '\n';
951 44157 : }
952 : #endif
953 :
954 : void LiveRange::print(raw_ostream &OS) const {
955 : if (empty())
956 74932 : OS << "EMPTY";
957 74284 : else {
958 74284 : for (const Segment &S : segments) {
959 : OS << S;
960 : assert(S.valno == getValNumInfo(S.valno->id) && "Bad VNInfo");
961 : }
962 : }
963 648 :
964 : // Print value number info.
965 : if (getNumValNums()) {
966 1296 : OS << " ";
967 : unsigned vnum = 0;
968 : for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e;
969 : ++i, ++vnum) {
970 : const VNInfo *vni = *i;
971 78197 : if (vnum) OS << ' ';
972 78197 : OS << vnum << '@';
973 : if (vni->isUnused()) {
974 : OS << 'x';
975 : } else {
976 : OS << vni->def;
977 78197 : if (vni->isPHIDef())
978 : OS << "-phi";
979 : }
980 986695 : }
981 : }
982 : }
983 :
984 : void LiveInterval::SubRange::print(raw_ostream &OS) const {
985 : OS << " L" << PrintLaneMask(LaneMask) << ' '
986 : << static_cast<const LiveRange&>(*this);
987 : }
988 :
989 : void LiveInterval::print(raw_ostream &OS) const {
990 986695 : OS << printReg(reg) << ' ';
991 2663483 : super::print(OS);
992 2356958 : // Print subranges
993 2356958 : for (const SubRange &SR : subranges())
994 4614702 : OS << SR;
995 : OS << " weight:" << weight;
996 : }
997 :
998 : #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
999 : LLVM_DUMP_METHOD void LiveRange::dump() const {
1000 : dbgs() << *this << '\n';
1001 986695 : }
1002 :
1003 : LLVM_DUMP_METHOD void LiveInterval::SubRange::dump() const {
1004 : dbgs() << *this << '\n';
1005 1360340 : }
1006 3389769 :
1007 2709599 : LLVM_DUMP_METHOD void LiveInterval::dump() const {
1008 : dbgs() << *this << '\n';
1009 : }
1010 : #endif
1011 :
1012 : #ifndef NDEBUG
1013 2709599 : void LiveRange::verify() const {
1014 9601 : for (const_iterator I = begin(), E = end(); I != E; ++I) {
1015 : assert(I->start.isValid());
1016 : assert(I->end.isValid());
1017 2699998 : assert(I->start < I->end);
1018 2699998 : assert(I->valno != nullptr);
1019 2699998 : assert(I->valno->id < valnos.size());
1020 9968 : assert(I->valno == valnos[I->valno->id]);
1021 9968 : if (std::next(I) != E) {
1022 : assert(I->end <= std::next(I)->start);
1023 : if (I->end == std::next(I)->start)
1024 : assert(I->valno != std::next(I)->valno);
1025 : }
1026 680170 : }
1027 : }
1028 :
1029 : void LiveInterval::verify(const MachineRegisterInfo *MRI) const {
1030 : super::verify();
1031 :
1032 : // Make sure SubRanges are fine and LaneMasks are disjunct.
1033 : LaneBitmask Mask;
1034 2215732 : LaneBitmask MaxMask = MRI != nullptr ? MRI->getMaxLaneMaskForVReg(reg)
1035 2458074 : : LaneBitmask::getAll();
1036 : for (const SubRange &SR : subranges()) {
1037 : // Subrange lanemask should be disjunct to any previous subrange masks.
1038 : assert((Mask & SR.LaneMask).none());
1039 : Mask |= SR.LaneMask;
1040 4832197 :
1041 3845502 : // subrange mask should not contained in maximum lane mask for the vreg.
1042 3845502 : assert((Mask & ~MaxMask).none());
1043 3845502 : // empty subranges must be removed.
1044 170963 : assert(!SR.empty());
1045 :
1046 7349078 : SR.verify();
1047 3845502 : // Main liverange should cover subrange.
1048 : assert(covers(SR));
1049 : }
1050 986695 : }
1051 11849 : #endif
1052 :
1053 : //===----------------------------------------------------------------------===//
1054 986695 : // LiveRangeUpdater class
1055 2215732 : //===----------------------------------------------------------------------===//
1056 1229037 : //
1057 986695 : // The LiveRangeUpdater class always maintains these invariants:
1058 : //
1059 : // - When LastStart is invalid, Spills is empty and the iterators are invalid.
1060 : // This is the initial state, and the state created by flush().
1061 : // In this state, isDirty() returns false.
1062 : //
1063 30033 : // Otherwise, segments are kept in three separate areas:
1064 : //
1065 30033 : // 1. [begin; WriteI) at the front of LR.
1066 102868 : // 2. [ReadI; end) at the back of LR.
1067 : // 3. Spills.
1068 30033 : //
1069 : // - LR.begin() <= WriteI <= ReadI <= LR.end().
1070 : // - Segments in all three areas are fully ordered and coalesced.
1071 : // - Segments in area 1 precede and can't coalesce with segments in area 2.
1072 : // - Segments in Spills precede and can't coalesce with segments in area 2.
1073 : // - No coalescing is possible between segments in Spills and segments in area
1074 : // 1, and there are no overlapping segments.
1075 18595 : //
1076 : // The segments in Spills are not ordered with respect to the segments in area
1077 : // 1. They need to be merged.
1078 18595 : //
1079 92861 : // When they exist, Spills.back().start <= LastStart,
1080 74266 : // and WriteI[-1].start <= LastStart.
1081 :
1082 18595 : #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1083 : void LiveRangeUpdater::print(raw_ostream &OS) const {
1084 : if (!isDirty()) {
1085 : if (LR)
1086 : OS << "Clean updater: " << *LR << '\n';
1087 : else
1088 16 : OS << "Null updater.\n";
1089 : return;
1090 : }
1091 : assert(LR && "Can't have null LR in dirty updater.");
1092 : OS << " updater with gap = " << (ReadI - WriteI)
1093 : << ", last start = " << LastStart
1094 : << ":\n Area 1:";
1095 : for (const auto &S : make_range(LR->begin(), WriteI))
1096 : OS << ' ' << S;
1097 16 : OS << "\n Spills:";
1098 : for (unsigned I = 0, E = Spills.size(); I != E; ++I)
1099 : OS << ' ' << Spills[I];
1100 : OS << "\n Area 2:";
1101 : for (const auto &S : make_range(ReadI, LR->end()))
1102 : OS << ' ' << S;
1103 88 : OS << '\n';
1104 72 : }
1105 72 :
1106 : LLVM_DUMP_METHOD void LiveRangeUpdater::dump() const {
1107 : print(errs());
1108 : }
1109 18 : #endif
1110 17 :
1111 17 : // Determine if A and B should be coalesced.
1112 7 : static inline bool coalescable(const LiveRange::Segment &A,
1113 : const LiveRange::Segment &B) {
1114 : assert(A.start <= B.start && "Unordered live segments.");
1115 : if (A.end == B.start)
1116 : return A.valno == B.valno;
1117 : if (A.end < B.start)
1118 : return false;
1119 : assert(A.valno == B.valno && "Cannot overlap different values");
1120 : return true;
1121 : }
1122 :
1123 18 : void LiveRangeUpdater::add(LiveRange::Segment Seg) {
1124 : assert(LR && "Cannot add to a null destination");
1125 :
1126 : // Fall back to the regular add method if the live range
1127 : // is using the segment set instead of the segment vector.
1128 18 : if (LR->segmentSet != nullptr) {
1129 17 : LR->addSegmentToSet(Seg);
1130 4 : return;
1131 : }
1132 4 :
1133 : // Flush the state if Start moves backwards.
1134 : if (!LastStart.isValid() || LastStart > Seg.start) {
1135 : if (isDirty())
1136 : flush();
1137 : // This brings us to an uninitialized state. Reinitialize.
1138 16 : assert(Spills.empty() && "Leftover spilled segments");
1139 : WriteI = ReadI = LR->begin();
1140 16 : }
1141 :
1142 : // Remember start for next time.
1143 1317458 : LastStart = Seg.start;
1144 :
1145 : // Advance ReadI until it ends after Seg.start.
1146 : LiveRange::iterator E = LR->end();
1147 : if (ReadI != E && ReadI->end <= Seg.start) {
1148 2634916 : // First try to close the gap between WriteI and ReadI with spills.
1149 : if (ReadI != WriteI)
1150 : mergeSpills();
1151 1317458 : // Then advance ReadI.
1152 : if (ReadI == WriteI)
1153 692495 : ReadI = WriteI = LR->find(Seg.start);
1154 : else
1155 692495 : while (ReadI != E && ReadI->end <= Seg.start)
1156 : *WriteI++ = *ReadI++;
1157 : }
1158 692495 :
1159 : assert(ReadI == E || ReadI->end > Seg.start);
1160 :
1161 : // Check if the ReadI segment begins early.
1162 284849 : if (ReadI != E && ReadI->start <= Seg.start) {
1163 : assert(ReadI->valno == Seg.valno && "Cannot overlap different values");
1164 : // Bail if Seg is completely contained in ReadI.
1165 : if (ReadI->end >= Seg.end)
1166 284849 : return;
1167 : // Coalesce into Seg.
1168 : Seg.start = ReadI->start;
1169 : ++ReadI;
1170 11196512 : }
1171 :
1172 : // Coalesce as much as possible from ReadI into Seg.
1173 11156691 : while (ReadI != E && coalescable(Seg, *ReadI)) {
1174 11156691 : Seg.end = std::max(Seg.end, ReadI->end);
1175 : ++ReadI;
1176 : }
1177 :
1178 11025789 : // Try coalescing Spills.back() into Seg.
1179 : if (!Spills.empty() && coalescable(Spills.back(), Seg)) {
1180 : Seg.start = Spills.back().start;
1181 : Seg.end = std::max(Spills.back().end, Seg.end);
1182 : Spills.pop_back();
1183 : }
1184 :
1185 : // Try coalescing Seg into WriteI[-1].
1186 : if (WriteI != LR->begin() && coalescable(WriteI[-1], Seg)) {
1187 343282 : WriteI[-1].end = std::max(WriteI[-1].end, Seg.end);
1188 : return;
1189 : }
1190 343282 :
1191 : // Seg doesn't coalesce with anything, and needs to be inserted somewhere.
1192 2918401 : if (WriteI != ReadI) {
1193 2918401 : *WriteI++ = Seg;
1194 2918401 : return;
1195 3258188 : }
1196 339787 :
1197 337949 : // Finally, append to LR or Spills.
1198 337949 : if (WriteI == E) {
1199 337949 : LR->segments.push_back(Seg);
1200 : WriteI = ReadI = LR->end();
1201 : } else
1202 : Spills.push_back(Seg);
1203 1902 : }
1204 1902 :
1205 : // Merge as many spilled segments as possible into the gap between WriteI
1206 1902 : // and ReadI. Advance WriteI to reflect the inserted instructions.
1207 1838 : void LiveRangeUpdater::mergeSpills() {
1208 : // Perform a backwards merge of Spills and [SpillI;WriteI).
1209 2918401 : size_t GapSize = ReadI - WriteI;
1210 : size_t NumMoved = std::min(Spills.size(), GapSize);
1211 2915991 : LiveRange::iterator Src = WriteI;
1212 3257371 : LiveRange::iterator Dst = Src + NumMoved;
1213 341380 : LiveRange::iterator SpillSrc = Spills.end();
1214 341380 : LiveRange::iterator B = LR->begin();
1215 :
1216 2915991 : // This is the new WriteI position after merging spills.
1217 2915991 : WriteI = Dst;
1218 :
1219 615683 : // Now merge Src and Spills backwards.
1220 : while (Src != Dst) {
1221 615683 : if (Src != B && Src[-1].start > SpillSrc[-1].start)
1222 2247356 : *--Dst = *--Src;
1223 1631673 : else
1224 : *--Dst = *--SpillSrc;
1225 1631673 : }
1226 : assert(NumMoved == size_t(Spills.end() - SpillSrc));
1227 : Spills.erase(SpillSrc, Spills.end());
1228 : }
1229 588339 :
1230 : void LiveRangeUpdater::flush() {
1231 : if (!isDirty())
1232 : return;
1233 : // Clear the dirty state.
1234 : LastStart = SlotIndex();
1235 125360 :
1236 : assert(LR && "Cannot add to a null destination");
1237 125360 :
1238 : // Nothing to merge?
1239 : if (Spills.empty()) {
1240 : LR->segments.erase(WriteI, ReadI);
1241 : LR->verify();
1242 : return;
1243 615683 : }
1244 152738 :
1245 : // Resize the WriteI - ReadI gap to match Spills.
1246 : size_t GapSize = ReadI - WriteI;
1247 615683 : if (GapSize < Spills.size()) {
1248 : // The gap is too small. Make some room.
1249 2445657 : size_t WritePos = WriteI - LR->begin();
1250 : LR->segments.insert(ReadI, Spills.size() - GapSize, LiveRange::Segment());
1251 6879652 : // This also invalidated ReadI, but it is recomputed below.
1252 4433995 : WriteI = LR->begin() + WritePos;
1253 2445657 : } else {
1254 : // Shrink the gap if necessary.
1255 : LR->segments.erase(WriteI + Spills.size(), ReadI);
1256 468423 : }
1257 : ReadI = WriteI + Spills.size();
1258 : mergeSpills();
1259 : LR->verify();
1260 : }
1261 468423 :
1262 : unsigned ConnectedVNInfoEqClasses::Classify(const LiveRange &LR) {
1263 468423 : // Create initial equivalence classes.
1264 1881007 : EqClass.clear();
1265 944161 : EqClass.grow(LR.getNumValNums());
1266 :
1267 : const VNInfo *used = nullptr, *unused = nullptr;
1268 :
1269 212782 : // Determine connections.
1270 212782 : for (const VNInfo *VNI : LR.valnos) {
1271 212782 : // Group all unused values into one class.
1272 154030 : if (VNI->isUnused()) {
1273 : if (unused)
1274 154030 : EqClass.join(unused->id, VNI->id);
1275 154030 : unused = VNI;
1276 : continue;
1277 : }
1278 468423 : used = VNI;
1279 : if (VNI->isPHIDef()) {
1280 26 : const MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
1281 78 : assert(MBB && "Phi-def has no defining MBB");
1282 : // Connect to values live out of predecessors.
1283 : for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(),
1284 : PE = MBB->pred_end(); PI != PE; ++PI)
1285 : if (const VNInfo *PVNI = LR.getVNInfoBefore(LIS.getMBBEndIdx(*PI)))
1286 : EqClass.join(VNI->id, PVNI->id);
1287 : } else {
1288 : // Normal value defined by an instruction. Check for two-addr redef.
1289 : // FIXME: This could be coincidental. Should we really check for a tied
1290 15 : // operand constraint?
1291 15 : // Note that VNI->def may be a use slot for an early clobber def.
1292 0 : if (const VNInfo *UVNI = LR.getVNInfoBefore(VNI->def))
1293 : EqClass.join(VNI->id, UVNI->id);
1294 41 : }
1295 26 : }
1296 :
1297 : // Lump all the unused values in with the last used value.
1298 : if (used && unused)
1299 : EqClass.join(used->id, unused->id);
1300 :
1301 15 : EqClass.compress();
1302 15 : return EqClass.getNumClasses();
1303 : }
1304 41 :
1305 : void ConnectedVNInfoEqClasses::Distribute(LiveInterval &LI, LiveInterval *LIV[],
1306 26 : MachineRegisterInfo &MRI) {
1307 26 : // Rewrite instructions.
1308 : for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(LI.reg),
1309 26 : RE = MRI.reg_end(); RI != RE;) {
1310 : MachineOperand &MO = *RI;
1311 : MachineInstr *MI = RI->getParent();
1312 26 : ++RI;
1313 26 : const VNInfo *VNI;
1314 0 : if (MI->isDebugValue()) {
1315 : // DBG_VALUE instructions don't have slot indexes, so get the index of
1316 : // the instruction before them. The value is defined there too.
1317 : SlotIndex Idx = LIS.getSlotIndexes()->getIndexBefore(*MI);
1318 15 : VNI = LI.Query(Idx).valueOut();
1319 : } else {
1320 4 : SlotIndex Idx = LIS.getInstructionIndex(*MI);
1321 4 : LiveQueryResult LRQ = LI.Query(Idx);
1322 4 : VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();
1323 4 : }
1324 : // In the case of an <undef> use that isn't tied to any def, VNI will be
1325 6 : // NULL. If the use is tied to a def, VNI will be the defined value.
1326 6 : if (!VNI)
1327 6 : continue;
1328 : if (unsigned EqClass = getEqClass(VNI))
1329 10 : MO.setReg(LIV[EqClass-1]->reg);
1330 : }
1331 6 :
1332 6 : // Distribute subregister liveranges.
1333 : if (LI.hasSubRanges()) {
1334 : unsigned NumComponents = EqClass.getNumClasses();
1335 : SmallVector<unsigned, 8> VNIMapping;
1336 : SmallVector<LiveInterval::SubRange*, 8> SubRanges;
1337 : BumpPtrAllocator &Allocator = LIS.getVNInfoAllocator();
1338 : for (LiveInterval::SubRange &SR : LI.subranges()) {
1339 : // Create new subranges in the split intervals and construct a mapping
1340 : // for the VNInfos in the subrange.
1341 : unsigned NumValNos = SR.valnos.size();
1342 : VNIMapping.clear();
1343 : VNIMapping.reserve(NumValNos);
1344 : SubRanges.clear();
1345 : SubRanges.resize(NumComponents-1, nullptr);
1346 : for (unsigned I = 0; I < NumValNos; ++I) {
1347 : const VNInfo &VNI = *SR.valnos[I];
1348 : unsigned ComponentNum;
1349 : if (VNI.isUnused()) {
1350 : ComponentNum = 0;
1351 : } else {
1352 : const VNInfo *MainRangeVNI = LI.getVNInfoAt(VNI.def);
1353 : assert(MainRangeVNI != nullptr
1354 : && "SubRange def must have corresponding main range def");
1355 : ComponentNum = getEqClass(MainRangeVNI);
1356 : if (ComponentNum > 0 && SubRanges[ComponentNum-1] == nullptr) {
1357 : SubRanges[ComponentNum-1]
1358 : = LIV[ComponentNum-1]->createSubRange(Allocator, SR.LaneMask);
1359 : }
1360 : }
1361 : VNIMapping.push_back(ComponentNum);
1362 : }
1363 : DistributeRange(SR, SubRanges.data(), VNIMapping);
1364 : }
1365 : LI.removeEmptySubRanges();
1366 : }
1367 :
1368 : // Distribute main liverange.
1369 : DistributeRange(LI, LIV, EqClass);
1370 : }
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