1441 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements the LiveRange and LiveInterval classes. Given some10// numbering of each the machine instructions an interval [i, j) is said to be a11// live range for register v if there is no instruction with number j' >= j12// such that v is live at j' and there is no instruction with number i' < i such13// 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). Each15// 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 20#include "llvm/CodeGen/LiveInterval.h"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"27#include "llvm/ADT/iterator_range.h"28#include "llvm/CodeGen/LiveIntervals.h"29#include "llvm/CodeGen/MachineBasicBlock.h"30#include "llvm/CodeGen/MachineInstr.h"31#include "llvm/CodeGen/MachineOperand.h"32#include "llvm/CodeGen/MachineRegisterInfo.h"33#include "llvm/CodeGen/SlotIndexes.h"34#include "llvm/CodeGen/TargetRegisterInfo.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"39#include "llvm/Support/raw_ostream.h"40#include <algorithm>41#include <cassert>42#include <cstddef>43#include <iterator>44#include <utility>45 46using namespace llvm;47 48namespace {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 the53// segment collection.54//55// Implementation of the class follows the Template design pattern. The base56// class contains generic algorithms that call collection-specific methods,57// which are provided in concrete subclasses. In order to avoid virtual calls58// 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 64template <typename ImplT, typename IteratorT, typename CollectionT>65class CalcLiveRangeUtilBase {66protected:67 LiveRange *LR;68 69protected:70 CalcLiveRangeUtilBase(LiveRange *LR) : LR(LR) {}71 72public:73 using Segment = LiveRange::Segment;74 using iterator = IteratorT;75 76 /// A counterpart of LiveRange::createDeadDef: Make sure the range has a77 /// value defined at @p Def.78 /// If @p ForVNI is null, and there is no value defined at @p Def, a new79 /// 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 where83 /// @p ForVNI is defined. If the range does not have a value defined at84 /// @p Def, the value @p ForVNI will be used instead of allocating a new85 /// one. If the range already has a value defined at @p Def, it must be86 /// same as @p ForVNI. In either case, @p ForVNI will be the return value.87 VNInfo *createDeadDef(SlotIndex Def, VNInfo::Allocator *VNInfoAllocator,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 same105 // register on an instruction. It doesn't make a lot of sense, but it is106 // 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 specified155 /// by I to end at the specified endpoint. To do this, we should156 /// merge and eliminate all segments that this will overlap157 /// 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 they172 // 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 specified184 /// by I to start at the specified endpoint. To do this, we should185 /// 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 and204 // 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 of224 // 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 with234 // 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 next242 // 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 its249 // 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 with256 // 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 with263 // anything.264 // Insert it.265 return segments().insert(I, S);266 }267 268private: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 ranges278// based on a segment vector.279//===----------------------------------------------------------------------===//280 281class CalcLiveRangeUtilVector;282using CalcLiveRangeUtilVectorBase =283 CalcLiveRangeUtilBase<CalcLiveRangeUtilVector, LiveRange::iterator,284 LiveRange::Segments>;285 286class CalcLiveRangeUtilVector : public CalcLiveRangeUtilVectorBase {287public:288 CalcLiveRangeUtilVector(LiveRange *LR) : CalcLiveRangeUtilVectorBase(LR) {}289 290private: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 ranges304// based on a segment set.305//===----------------------------------------------------------------------===//306 307class CalcLiveRangeUtilSet;308using CalcLiveRangeUtilSetBase =309 CalcLiveRangeUtilBase<CalcLiveRangeUtilSet, LiveRange::SegmentSet::iterator,310 LiveRange::SegmentSet>;311 312class CalcLiveRangeUtilSet : public CalcLiveRangeUtilSetBase {313public:314 CalcLiveRangeUtilSet(LiveRange *LR) : CalcLiveRangeUtilSetBase(LR) {}315 316private: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 namespace345 346//===----------------------------------------------------------------------===//347// LiveRange methods348//===----------------------------------------------------------------------===//349 350LiveRange::iterator LiveRange::find(SlotIndex Pos) {351 return llvm::partition_point(*this,352 [&](const Segment &X) { return X.end <= Pos; });353}354 355VNInfo *LiveRange::createDeadDef(SlotIndex Def, VNInfo::Allocator &VNIAlloc) {356 // Use the segment set, if it is available.357 if (segmentSet != nullptr)358 return CalcLiveRangeUtilSet(this).createDeadDef(Def, &VNIAlloc, nullptr);359 // Otherwise use the segment vector.360 return CalcLiveRangeUtilVector(this).createDeadDef(Def, &VNIAlloc, nullptr);361}362 363VNInfo *LiveRange::createDeadDef(VNInfo *VNI) {364 // Use the segment set, if it is available.365 if (segmentSet != nullptr)366 return CalcLiveRangeUtilSet(this).createDeadDef(VNI->def, nullptr, VNI);367 // Otherwise use the segment vector.368 return CalcLiveRangeUtilVector(this).createDeadDef(VNI->def, nullptr, VNI);369}370 371// overlaps - Return true if the intersection of the two live ranges is372// not empty.373//374// An example for overlaps():375//376// 0: A = ...377// 4: B = ...378// 8: C = A + B ;; last use of A379//380// The live ranges should look like:381//382// A = [3, 11)383// B = [7, x)384// C = [11, y)385//386// A->overlaps(C) should return false since we want to be able to join387// A and C.388//389bool LiveRange::overlapsFrom(const LiveRange& other,390 const_iterator StartPos) const {391 assert(!empty() && "empty range");392 const_iterator i = begin();393 const_iterator ie = end();394 const_iterator j = StartPos;395 const_iterator je = other.end();396 397 assert((StartPos->start <= i->start || StartPos == other.begin()) &&398 StartPos != other.end() && "Bogus start position hint!");399 400 if (i->start < j->start) {401 i = std::upper_bound(i, ie, j->start);402 if (i != begin()) --i;403 } else if (j->start < i->start) {404 ++StartPos;405 if (StartPos != other.end() && StartPos->start <= i->start) {406 assert(StartPos < other.end() && i < end());407 j = std::upper_bound(j, je, i->start);408 if (j != other.begin()) --j;409 }410 } else {411 return true;412 }413 414 if (j == je) return false;415 416 while (i != ie) {417 if (i->start > j->start) {418 std::swap(i, j);419 std::swap(ie, je);420 }421 422 if (i->end > j->start)423 return true;424 ++i;425 }426 427 return false;428}429 430bool LiveRange::overlaps(const LiveRange &Other, const CoalescerPair &CP,431 const SlotIndexes &Indexes) const {432 assert(!empty() && "empty range");433 if (Other.empty())434 return false;435 436 // Use binary searches to find initial positions.437 const_iterator I = find(Other.beginIndex());438 const_iterator IE = end();439 if (I == IE)440 return false;441 const_iterator J = Other.find(I->start);442 const_iterator JE = Other.end();443 if (J == JE)444 return false;445 446 while (true) {447 // J has just been advanced to satisfy:448 assert(J->end > I->start);449 // Check for an overlap.450 if (J->start < I->end) {451 // I and J are overlapping. Find the later start.452 SlotIndex Def = std::max(I->start, J->start);453 // Allow the overlap if Def is a coalescable copy.454 if (Def.isBlock() ||455 !CP.isCoalescable(Indexes.getInstructionFromIndex(Def)))456 return true;457 }458 // Advance the iterator that ends first to check for more overlaps.459 if (J->end > I->end) {460 std::swap(I, J);461 std::swap(IE, JE);462 }463 // Advance J until J->end > I->start.464 do465 if (++J == JE)466 return false;467 while (J->end <= I->start);468 }469}470 471/// overlaps - Return true if the live range overlaps an interval specified472/// by [Start, End).473bool LiveRange::overlaps(SlotIndex Start, SlotIndex End) const {474 assert(Start < End && "Invalid range");475 const_iterator I = lower_bound(*this, End);476 return I != begin() && (--I)->end > Start;477}478 479bool LiveRange::covers(const LiveRange &Other) const {480 if (empty())481 return Other.empty();482 483 const_iterator I = begin();484 for (const Segment &O : Other.segments) {485 I = advanceTo(I, O.start);486 if (I == end() || I->start > O.start)487 return false;488 489 // Check adjacent live segments and see if we can get behind O.end.490 while (I->end < O.end) {491 const_iterator Last = I;492 // Get next segment and abort if it was not adjacent.493 ++I;494 if (I == end() || Last->end != I->start)495 return false;496 }497 }498 return true;499}500 501/// ValNo is dead, remove it. If it is the largest value number, just nuke it502/// (and any other deleted values neighboring it), otherwise mark it as ~1U so503/// it can be nuked later.504void LiveRange::markValNoForDeletion(VNInfo *ValNo) {505 if (ValNo->id == getNumValNums()-1) {506 do {507 valnos.pop_back();508 } while (!valnos.empty() && valnos.back()->isUnused());509 } else {510 ValNo->markUnused();511 }512}513 514/// RenumberValues - Renumber all values in order of appearance and delete the515/// remaining unused values.516void LiveRange::RenumberValues() {517 SmallPtrSet<VNInfo*, 8> Seen;518 valnos.clear();519 for (const Segment &S : segments) {520 VNInfo *VNI = S.valno;521 if (!Seen.insert(VNI).second)522 continue;523 assert(!VNI->isUnused() && "Unused valno used by live segment");524 VNI->id = (unsigned)valnos.size();525 valnos.push_back(VNI);526 }527}528 529void LiveRange::addSegmentToSet(Segment S) {530 CalcLiveRangeUtilSet(this).addSegment(S);531}532 533LiveRange::iterator LiveRange::addSegment(Segment S) {534 // Use the segment set, if it is available.535 if (segmentSet != nullptr) {536 addSegmentToSet(S);537 return end();538 }539 // Otherwise use the segment vector.540 return CalcLiveRangeUtilVector(this).addSegment(S);541}542 543void LiveRange::append(const Segment S) {544 // Check that the segment belongs to the back of the list.545 assert(segments.empty() || segments.back().end <= S.start);546 segments.push_back(S);547}548 549std::pair<VNInfo*,bool> LiveRange::extendInBlock(ArrayRef<SlotIndex> Undefs,550 SlotIndex StartIdx, SlotIndex Kill) {551 // Use the segment set, if it is available.552 if (segmentSet != nullptr)553 return CalcLiveRangeUtilSet(this).extendInBlock(Undefs, StartIdx, Kill);554 // Otherwise use the segment vector.555 return CalcLiveRangeUtilVector(this).extendInBlock(Undefs, StartIdx, Kill);556}557 558VNInfo *LiveRange::extendInBlock(SlotIndex StartIdx, SlotIndex Kill) {559 // Use the segment set, if it is available.560 if (segmentSet != nullptr)561 return CalcLiveRangeUtilSet(this).extendInBlock(StartIdx, Kill);562 // Otherwise use the segment vector.563 return CalcLiveRangeUtilVector(this).extendInBlock(StartIdx, Kill);564}565 566void LiveRange::removeSegment(SlotIndex Start, SlotIndex End,567 bool RemoveDeadValNo) {568 // Find the Segment containing this span.569 iterator I = find(Start);570 571 // No Segment found, so nothing to do.572 if (I == end())573 return;574 575 assert(I->containsInterval(Start, End)576 && "Segment is not entirely in range!");577 578 // If the span we are removing is at the start of the Segment, adjust it.579 VNInfo *ValNo = I->valno;580 if (I->start == Start) {581 if (I->end == End) {582 segments.erase(I); // Removed the whole Segment.583 584 if (RemoveDeadValNo)585 removeValNoIfDead(ValNo);586 } else587 I->start = End;588 return;589 }590 591 // Otherwise if the span we are removing is at the end of the Segment,592 // adjust the other way.593 if (I->end == End) {594 I->end = Start;595 return;596 }597 598 // Otherwise, we are splitting the Segment into two pieces.599 SlotIndex OldEnd = I->end;600 I->end = Start; // Trim the old segment.601 602 // Insert the new one.603 segments.insert(std::next(I), Segment(End, OldEnd, ValNo));604}605 606LiveRange::iterator LiveRange::removeSegment(iterator I, bool RemoveDeadValNo) {607 VNInfo *ValNo = I->valno;608 I = segments.erase(I);609 if (RemoveDeadValNo)610 removeValNoIfDead(ValNo);611 return I;612}613 614void LiveRange::removeValNoIfDead(VNInfo *ValNo) {615 if (none_of(*this, [=](const Segment &S) { return S.valno == ValNo; }))616 markValNoForDeletion(ValNo);617}618 619/// removeValNo - Remove all the segments defined by the specified value#.620/// Also remove the value# from value# list.621void LiveRange::removeValNo(VNInfo *ValNo) {622 if (empty()) return;623 llvm::erase_if(segments,624 [ValNo](const Segment &S) { return S.valno == ValNo; });625 // Now that ValNo is dead, remove it.626 markValNoForDeletion(ValNo);627}628 629void LiveRange::join(LiveRange &Other,630 const int *LHSValNoAssignments,631 const int *RHSValNoAssignments,632 SmallVectorImpl<VNInfo *> &NewVNInfo) {633 assert(verify());634 assert(Other.verify());635 636 // Determine if any of our values are mapped. This is uncommon, so we want637 // to avoid the range scan if not.638 bool MustMapCurValNos = false;639 unsigned NumVals = getNumValNums();640 unsigned NumNewVals = NewVNInfo.size();641 for (unsigned i = 0; i != NumVals; ++i) {642 unsigned LHSValID = LHSValNoAssignments[i];643 if (i != LHSValID ||644 (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) {645 MustMapCurValNos = true;646 break;647 }648 }649 650 // If we have to apply a mapping to our base range assignment, rewrite it now.651 if (MustMapCurValNos && !empty()) {652 // Map the first live range.653 654 iterator OutIt = begin();655 OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]];656 for (iterator I = std::next(OutIt), E = end(); I != E; ++I) {657 VNInfo* nextValNo = NewVNInfo[LHSValNoAssignments[I->valno->id]];658 assert(nextValNo && "Huh?");659 660 // If this live range has the same value # as its immediate predecessor,661 // and if they are neighbors, remove one Segment. This happens when we662 // have [0,4:0)[4,7:1) and map 0/1 onto the same value #.663 if (OutIt->valno == nextValNo && OutIt->end == I->start) {664 OutIt->end = I->end;665 } else {666 // Didn't merge. Move OutIt to the next segment,667 ++OutIt;668 OutIt->valno = nextValNo;669 if (OutIt != I) {670 OutIt->start = I->start;671 OutIt->end = I->end;672 }673 }674 }675 // If we merge some segments, chop off the end.676 ++OutIt;677 segments.erase(OutIt, end());678 }679 680 // Rewrite Other values before changing the VNInfo ids.681 // This can leave Other in an invalid state because we're not coalescing682 // touching segments that now have identical values. That's OK since Other is683 // not supposed to be valid after calling join();684 for (Segment &S : Other.segments)685 S.valno = NewVNInfo[RHSValNoAssignments[S.valno->id]];686 687 // Update val# info. Renumber them and make sure they all belong to this688 // LiveRange now. Also remove dead val#'s.689 unsigned NumValNos = 0;690 for (unsigned i = 0; i < NumNewVals; ++i) {691 VNInfo *VNI = NewVNInfo[i];692 if (VNI) {693 if (NumValNos >= NumVals)694 valnos.push_back(VNI);695 else696 valnos[NumValNos] = VNI;697 VNI->id = NumValNos++; // Renumber val#.698 }699 }700 if (NumNewVals < NumVals)701 valnos.resize(NumNewVals); // shrinkify702 703 // Okay, now insert the RHS live segments into the LHS.704 LiveRangeUpdater Updater(this);705 for (Segment &S : Other.segments)706 Updater.add(S);707}708 709/// Merge all of the segments in RHS into this live range as the specified710/// value number. The segments in RHS are allowed to overlap with segments in711/// the current range, but only if the overlapping segments have the712/// specified value number.713void LiveRange::MergeSegmentsInAsValue(const LiveRange &RHS,714 VNInfo *LHSValNo) {715 LiveRangeUpdater Updater(this);716 for (const Segment &S : RHS.segments)717 Updater.add(S.start, S.end, LHSValNo);718}719 720/// MergeValueInAsValue - Merge all of the live segments of a specific val#721/// in RHS into this live range as the specified value number.722/// The segments in RHS are allowed to overlap with segments in the723/// current range, it will replace the value numbers of the overlaped724/// segments with the specified value number.725void LiveRange::MergeValueInAsValue(const LiveRange &RHS,726 const VNInfo *RHSValNo,727 VNInfo *LHSValNo) {728 LiveRangeUpdater Updater(this);729 for (const Segment &S : RHS.segments)730 if (S.valno == RHSValNo)731 Updater.add(S.start, S.end, LHSValNo);732}733 734/// MergeValueNumberInto - This method is called when two value nubmers735/// are found to be equivalent. This eliminates V1, replacing all736/// segments with the V1 value number with the V2 value number. This can737/// cause merging of V1/V2 values numbers and compaction of the value space.738VNInfo *LiveRange::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) {739 assert(V1 != V2 && "Identical value#'s are always equivalent!");740 741 // This code actually merges the (numerically) larger value number into the742 // smaller value number, which is likely to allow us to compactify the value743 // space. The only thing we have to be careful of is to preserve the744 // instruction that defines the result value.745 746 // Make sure V2 is smaller than V1.747 if (V1->id < V2->id) {748 V1->copyFrom(*V2);749 std::swap(V1, V2);750 }751 752 // Merge V1 segments into V2.753 for (iterator I = begin(); I != end(); ) {754 iterator S = I++;755 if (S->valno != V1) continue; // Not a V1 Segment.756 757 // Okay, we found a V1 live range. If it had a previous, touching, V2 live758 // range, extend it.759 if (S != begin()) {760 iterator Prev = S-1;761 if (Prev->valno == V2 && Prev->end == S->start) {762 Prev->end = S->end;763 764 // Erase this live-range.765 segments.erase(S);766 I = Prev+1;767 S = Prev;768 }769 }770 771 // Okay, now we have a V1 or V2 live range that is maximally merged forward.772 // Ensure that it is a V2 live-range.773 S->valno = V2;774 775 // If we can merge it into later V2 segments, do so now. We ignore any776 // following V1 segments, as they will be merged in subsequent iterations777 // of the loop.778 if (I != end()) {779 if (I->start == S->end && I->valno == V2) {780 S->end = I->end;781 segments.erase(I);782 I = S+1;783 }784 }785 }786 787 // Now that V1 is dead, remove it.788 markValNoForDeletion(V1);789 790 return V2;791}792 793void LiveRange::flushSegmentSet() {794 assert(segmentSet != nullptr && "segment set must have been created");795 assert(796 segments.empty() &&797 "segment set can be used only initially before switching to the array");798 segments.append(segmentSet->begin(), segmentSet->end());799 segmentSet = nullptr;800 assert(verify());801}802 803bool LiveRange::isLiveAtIndexes(ArrayRef<SlotIndex> Slots) const {804 ArrayRef<SlotIndex>::iterator SlotI = Slots.begin();805 ArrayRef<SlotIndex>::iterator SlotE = Slots.end();806 807 // If there are no regmask slots, we have nothing to search.808 if (SlotI == SlotE)809 return false;810 811 // Start our search at the first segment that ends after the first slot.812 const_iterator SegmentI = find(*SlotI);813 const_iterator SegmentE = end();814 815 // If there are no segments that end after the first slot, we're done.816 if (SegmentI == SegmentE)817 return false;818 819 // Look for each slot in the live range.820 for ( ; SlotI != SlotE; ++SlotI) {821 // Go to the next segment that ends after the current slot.822 // The slot may be within a hole in the range.823 SegmentI = advanceTo(SegmentI, *SlotI);824 if (SegmentI == SegmentE)825 return false;826 827 // If this segment contains the slot, we're done.828 if (SegmentI->contains(*SlotI))829 return true;830 // Otherwise, look for the next slot.831 }832 833 // We didn't find a segment containing any of the slots.834 return false;835}836 837void LiveInterval::freeSubRange(SubRange *S) {838 S->~SubRange();839 // Memory was allocated with BumpPtr allocator and is not freed here.840}841 842void LiveInterval::removeEmptySubRanges() {843 SubRange **NextPtr = &SubRanges;844 SubRange *I = *NextPtr;845 while (I != nullptr) {846 if (!I->empty()) {847 NextPtr = &I->Next;848 I = *NextPtr;849 continue;850 }851 // Skip empty subranges until we find the first nonempty one.852 do {853 SubRange *Next = I->Next;854 freeSubRange(I);855 I = Next;856 } while (I != nullptr && I->empty());857 *NextPtr = I;858 }859}860 861void LiveInterval::clearSubRanges() {862 for (SubRange *I = SubRanges, *Next; I != nullptr; I = Next) {863 Next = I->Next;864 freeSubRange(I);865 }866 SubRanges = nullptr;867}868 869/// For each VNI in \p SR, check whether or not that value defines part870/// of the mask describe by \p LaneMask and if not, remove that value871/// from \p SR.872static void stripValuesNotDefiningMask(Register Reg, LiveInterval::SubRange &SR,873 LaneBitmask LaneMask,874 const SlotIndexes &Indexes,875 const TargetRegisterInfo &TRI,876 unsigned ComposeSubRegIdx) {877 // Phys reg should not be tracked at subreg level.878 // Same for noreg (Reg == 0).879 if (!Reg || !Reg.isVirtual())880 return;881 // Remove the values that don't define those lanes.882 SmallVector<VNInfo *, 8> ToBeRemoved;883 for (VNInfo *VNI : SR.valnos) {884 if (VNI->isUnused())885 continue;886 // PHI definitions don't have MI attached, so there is nothing887 // we can use to strip the VNI.888 if (VNI->isPHIDef())889 continue;890 const MachineInstr *MI = Indexes.getInstructionFromIndex(VNI->def);891 assert(MI && "Cannot find the definition of a value");892 bool hasDef = false;893 for (ConstMIBundleOperands MOI(*MI); MOI.isValid(); ++MOI) {894 if (!MOI->isReg() || !MOI->isDef())895 continue;896 if (MOI->getReg() != Reg)897 continue;898 LaneBitmask OrigMask = TRI.getSubRegIndexLaneMask(MOI->getSubReg());899 LaneBitmask ExpectedDefMask =900 ComposeSubRegIdx901 ? TRI.composeSubRegIndexLaneMask(ComposeSubRegIdx, OrigMask)902 : OrigMask;903 if ((ExpectedDefMask & LaneMask).none())904 continue;905 hasDef = true;906 break;907 }908 909 if (!hasDef)910 ToBeRemoved.push_back(VNI);911 }912 for (VNInfo *VNI : ToBeRemoved)913 SR.removeValNo(VNI);914 915 // If the subrange is empty at this point, the MIR is invalid. Do not assert916 // and let the verifier catch this case.917}918 919void LiveInterval::refineSubRanges(920 BumpPtrAllocator &Allocator, LaneBitmask LaneMask,921 std::function<void(LiveInterval::SubRange &)> Apply,922 const SlotIndexes &Indexes, const TargetRegisterInfo &TRI,923 unsigned ComposeSubRegIdx) {924 LaneBitmask ToApply = LaneMask;925 for (SubRange &SR : subranges()) {926 LaneBitmask SRMask = SR.LaneMask;927 LaneBitmask Matching = SRMask & LaneMask;928 if (Matching.none())929 continue;930 931 SubRange *MatchingRange;932 if (SRMask == Matching) {933 // The subrange fits (it does not cover bits outside \p LaneMask).934 MatchingRange = &SR;935 } else {936 // We have to split the subrange into a matching and non-matching part.937 // Reduce lanemask of existing lane to non-matching part.938 SR.LaneMask = SRMask & ~Matching;939 // Create a new subrange for the matching part940 MatchingRange = createSubRangeFrom(Allocator, Matching, SR);941 // Now that the subrange is split in half, make sure we942 // only keep in the subranges the VNIs that touch the related half.943 stripValuesNotDefiningMask(reg(), *MatchingRange, Matching, Indexes, TRI,944 ComposeSubRegIdx);945 stripValuesNotDefiningMask(reg(), SR, SR.LaneMask, Indexes, TRI,946 ComposeSubRegIdx);947 }948 Apply(*MatchingRange);949 ToApply &= ~Matching;950 }951 // Create a new subrange if there are uncovered bits left.952 if (ToApply.any()) {953 SubRange *NewRange = createSubRange(Allocator, ToApply);954 Apply(*NewRange);955 }956}957 958unsigned LiveInterval::getSize() const {959 unsigned Sum = 0;960 for (const Segment &S : segments)961 Sum += S.start.distance(S.end);962 return Sum;963}964 965void LiveInterval::computeSubRangeUndefs(SmallVectorImpl<SlotIndex> &Undefs,966 LaneBitmask LaneMask,967 const MachineRegisterInfo &MRI,968 const SlotIndexes &Indexes) const {969 assert(reg().isVirtual());970 LaneBitmask VRegMask = MRI.getMaxLaneMaskForVReg(reg());971 assert((VRegMask & LaneMask).any());972 const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();973 for (const MachineOperand &MO : MRI.def_operands(reg())) {974 if (!MO.isUndef())975 continue;976 unsigned SubReg = MO.getSubReg();977 assert(SubReg != 0 && "Undef should only be set on subreg defs");978 LaneBitmask DefMask = TRI.getSubRegIndexLaneMask(SubReg);979 LaneBitmask UndefMask = VRegMask & ~DefMask;980 if ((UndefMask & LaneMask).any()) {981 const MachineInstr &MI = *MO.getParent();982 bool EarlyClobber = MO.isEarlyClobber();983 SlotIndex Pos = Indexes.getInstructionIndex(MI).getRegSlot(EarlyClobber);984 Undefs.push_back(Pos);985 }986 }987}988 989raw_ostream& llvm::operator<<(raw_ostream& OS, const LiveRange::Segment &S) {990 return OS << '[' << S.start << ',' << S.end << ':' << S.valno->id << ')';991}992 993#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)994LLVM_DUMP_METHOD void LiveRange::Segment::dump() const {995 dbgs() << *this << '\n';996}997#endif998 999void VNInfo::print(raw_ostream &OS) const {1000 OS << id << '@';1001 if (isUnused()) {1002 OS << 'x';1003 } else {1004 OS << def;1005 if (isPHIDef())1006 OS << "-phi";1007 }1008}1009 1010void LiveRange::print(raw_ostream &OS) const {1011 if (empty())1012 OS << "EMPTY";1013 else {1014 for (const Segment &S : segments) {1015 OS << S;1016 assert(S.valno == getValNumInfo(S.valno->id) && "Bad VNInfo");1017 }1018 }1019 1020 // Print value number info.1021 if (getNumValNums()) {1022 OS << ' ';1023 unsigned vnum = 0;1024 for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e;1025 ++i, ++vnum) {1026 const VNInfo *vni = *i;1027 if (vnum)1028 OS << ' ';1029 OS << *vni;1030 assert(vnum == vni->id && "Bad VNInfo");1031 }1032 }1033}1034 1035void LiveInterval::SubRange::print(raw_ostream &OS) const {1036 OS << " L" << PrintLaneMask(LaneMask) << ' '1037 << static_cast<const LiveRange &>(*this);1038}1039 1040void LiveInterval::print(raw_ostream &OS) const {1041 OS << printReg(reg()) << ' ';1042 super::print(OS);1043 // Print subranges1044 for (const SubRange &SR : subranges())1045 OS << SR;1046 OS << " weight:" << Weight;1047}1048 1049#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)1050LLVM_DUMP_METHOD void VNInfo::dump() const { dbgs() << *this << '\n'; }1051 1052LLVM_DUMP_METHOD void LiveRange::dump() const { dbgs() << *this << '\n'; }1053 1054LLVM_DUMP_METHOD void LiveInterval::SubRange::dump() const {1055 dbgs() << *this << '\n';1056}1057 1058LLVM_DUMP_METHOD void LiveInterval::dump() const {1059 dbgs() << *this << '\n';1060}1061#endif1062 1063#ifndef NDEBUG1064bool LiveRange::verify() const {1065 for (const_iterator I = begin(), E = end(); I != E; ++I) {1066 if (!I->start.isValid())1067 return false;1068 if (!I->end.isValid())1069 return false;1070 if (I->start >= I->end)1071 return false;1072 if (I->valno == nullptr)1073 return false;1074 if (I->valno->id >= valnos.size())1075 return false;1076 if (I->valno != valnos[I->valno->id])1077 return false;1078 if (std::next(I) != E) {1079 if (I->end > std::next(I)->start)1080 return false;1081 if (I->end == std::next(I)->start) {1082 if (I->valno == std::next(I)->valno)1083 return false;1084 }1085 }1086 }1087 1088 return true;1089}1090 1091bool LiveInterval::verify(const MachineRegisterInfo *MRI) const {1092 if (!super::verify())1093 return false;1094 1095 // Make sure SubRanges are fine and LaneMasks are disjunct.1096 LaneBitmask Mask;1097 LaneBitmask MaxMask = MRI != nullptr ? MRI->getMaxLaneMaskForVReg(reg())1098 : LaneBitmask::getAll();1099 for (const SubRange &SR : subranges()) {1100 // Subrange lanemask should be disjunct to any previous subrange masks.1101 if ((Mask & SR.LaneMask).any())1102 return false;1103 1104 Mask |= SR.LaneMask;1105 1106 // subrange mask should not contained in maximum lane mask for the vreg.1107 if ((Mask & ~MaxMask).any())1108 return false;1109 1110 // empty subranges must be removed.1111 if (SR.empty())1112 return false;1113 1114 if (!SR.verify())1115 return false;1116 1117 // Main liverange should cover subrange.1118 if (!covers(SR))1119 return false;1120 }1121 1122 return true;1123}1124#endif1125 1126//===----------------------------------------------------------------------===//1127// LiveRangeUpdater class1128//===----------------------------------------------------------------------===//1129//1130// The LiveRangeUpdater class always maintains these invariants:1131//1132// - When LastStart is invalid, Spills is empty and the iterators are invalid.1133// This is the initial state, and the state created by flush().1134// In this state, isDirty() returns false.1135//1136// Otherwise, segments are kept in three separate areas:1137//1138// 1. [begin; WriteI) at the front of LR.1139// 2. [ReadI; end) at the back of LR.1140// 3. Spills.1141//1142// - LR.begin() <= WriteI <= ReadI <= LR.end().1143// - Segments in all three areas are fully ordered and coalesced.1144// - Segments in area 1 precede and can't coalesce with segments in area 2.1145// - Segments in Spills precede and can't coalesce with segments in area 2.1146// - No coalescing is possible between segments in Spills and segments in area1147// 1, and there are no overlapping segments.1148//1149// The segments in Spills are not ordered with respect to the segments in area1150// 1. They need to be merged.1151//1152// When they exist, Spills.back().start <= LastStart,1153// and WriteI[-1].start <= LastStart.1154 1155#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)1156void LiveRangeUpdater::print(raw_ostream &OS) const {1157 if (!isDirty()) {1158 if (LR)1159 OS << "Clean updater: " << *LR << '\n';1160 else1161 OS << "Null updater.\n";1162 return;1163 }1164 assert(LR && "Can't have null LR in dirty updater.");1165 OS << " updater with gap = " << (ReadI - WriteI)1166 << ", last start = " << LastStart1167 << ":\n Area 1:";1168 for (const auto &S : make_range(LR->begin(), WriteI))1169 OS << ' ' << S;1170 OS << "\n Spills:";1171 for (const LiveRange::Segment &Spill : Spills)1172 OS << ' ' << Spill;1173 OS << "\n Area 2:";1174 for (const auto &S : make_range(ReadI, LR->end()))1175 OS << ' ' << S;1176 OS << '\n';1177}1178 1179LLVM_DUMP_METHOD void LiveRangeUpdater::dump() const {1180 print(errs());1181}1182#endif1183 1184// Determine if A and B should be coalesced.1185static inline bool coalescable(const LiveRange::Segment &A,1186 const LiveRange::Segment &B) {1187 assert(A.start <= B.start && "Unordered live segments.");1188 if (A.end == B.start)1189 return A.valno == B.valno;1190 if (A.end < B.start)1191 return false;1192 assert(A.valno == B.valno && "Cannot overlap different values");1193 return true;1194}1195 1196void LiveRangeUpdater::add(LiveRange::Segment Seg) {1197 assert(LR && "Cannot add to a null destination");1198 1199 // Fall back to the regular add method if the live range1200 // is using the segment set instead of the segment vector.1201 if (LR->segmentSet != nullptr) {1202 LR->addSegmentToSet(Seg);1203 return;1204 }1205 1206 // Flush the state if Start moves backwards.1207 if (!LastStart.isValid() || LastStart > Seg.start) {1208 if (isDirty())1209 flush();1210 // This brings us to an uninitialized state. Reinitialize.1211 assert(Spills.empty() && "Leftover spilled segments");1212 WriteI = ReadI = LR->begin();1213 }1214 1215 // Remember start for next time.1216 LastStart = Seg.start;1217 1218 // Advance ReadI until it ends after Seg.start.1219 LiveRange::iterator E = LR->end();1220 if (ReadI != E && ReadI->end <= Seg.start) {1221 // First try to close the gap between WriteI and ReadI with spills.1222 if (ReadI != WriteI)1223 mergeSpills();1224 // Then advance ReadI.1225 if (ReadI == WriteI)1226 ReadI = WriteI = LR->find(Seg.start);1227 else1228 while (ReadI != E && ReadI->end <= Seg.start)1229 *WriteI++ = *ReadI++;1230 }1231 1232 assert(ReadI == E || ReadI->end > Seg.start);1233 1234 // Check if the ReadI segment begins early.1235 if (ReadI != E && ReadI->start <= Seg.start) {1236 assert(ReadI->valno == Seg.valno && "Cannot overlap different values");1237 // Bail if Seg is completely contained in ReadI.1238 if (ReadI->end >= Seg.end)1239 return;1240 // Coalesce into Seg.1241 Seg.start = ReadI->start;1242 ++ReadI;1243 }1244 1245 // Coalesce as much as possible from ReadI into Seg.1246 while (ReadI != E && coalescable(Seg, *ReadI)) {1247 Seg.end = std::max(Seg.end, ReadI->end);1248 ++ReadI;1249 }1250 1251 // Try coalescing Spills.back() into Seg.1252 if (!Spills.empty() && coalescable(Spills.back(), Seg)) {1253 Seg.start = Spills.back().start;1254 Seg.end = std::max(Spills.back().end, Seg.end);1255 Spills.pop_back();1256 }1257 1258 // Try coalescing Seg into WriteI[-1].1259 if (WriteI != LR->begin() && coalescable(WriteI[-1], Seg)) {1260 WriteI[-1].end = std::max(WriteI[-1].end, Seg.end);1261 return;1262 }1263 1264 // Seg doesn't coalesce with anything, and needs to be inserted somewhere.1265 if (WriteI != ReadI) {1266 *WriteI++ = Seg;1267 return;1268 }1269 1270 // Finally, append to LR or Spills.1271 if (WriteI == E) {1272 LR->segments.push_back(Seg);1273 WriteI = ReadI = LR->end();1274 } else1275 Spills.push_back(Seg);1276}1277 1278// Merge as many spilled segments as possible into the gap between WriteI1279// and ReadI. Advance WriteI to reflect the inserted instructions.1280void LiveRangeUpdater::mergeSpills() {1281 // Perform a backwards merge of Spills and [SpillI;WriteI).1282 size_t GapSize = ReadI - WriteI;1283 size_t NumMoved = std::min(Spills.size(), GapSize);1284 LiveRange::iterator Src = WriteI;1285 LiveRange::iterator Dst = Src + NumMoved;1286 LiveRange::iterator SpillSrc = Spills.end();1287 LiveRange::iterator B = LR->begin();1288 1289 // This is the new WriteI position after merging spills.1290 WriteI = Dst;1291 1292 // Now merge Src and Spills backwards.1293 while (Src != Dst) {1294 if (Src != B && Src[-1].start > SpillSrc[-1].start)1295 *--Dst = *--Src;1296 else1297 *--Dst = *--SpillSrc;1298 }1299 assert(NumMoved == size_t(Spills.end() - SpillSrc));1300 Spills.erase(SpillSrc, Spills.end());1301}1302 1303void LiveRangeUpdater::flush() {1304 if (!isDirty())1305 return;1306 // Clear the dirty state.1307 LastStart = SlotIndex();1308 1309 assert(LR && "Cannot add to a null destination");1310 1311 // Nothing to merge?1312 if (Spills.empty()) {1313 LR->segments.erase(WriteI, ReadI);1314 assert(LR->verify());1315 return;1316 }1317 1318 // Resize the WriteI - ReadI gap to match Spills.1319 size_t GapSize = ReadI - WriteI;1320 if (GapSize < Spills.size()) {1321 // The gap is too small. Make some room.1322 size_t WritePos = WriteI - LR->begin();1323 LR->segments.insert(ReadI, Spills.size() - GapSize, LiveRange::Segment());1324 // This also invalidated ReadI, but it is recomputed below.1325 WriteI = LR->begin() + WritePos;1326 } else {1327 // Shrink the gap if necessary.1328 LR->segments.erase(WriteI + Spills.size(), ReadI);1329 }1330 ReadI = WriteI + Spills.size();1331 mergeSpills();1332 assert(LR->verify());1333}1334 1335unsigned ConnectedVNInfoEqClasses::Classify(const LiveRange &LR) {1336 // Create initial equivalence classes.1337 EqClass.clear();1338 EqClass.grow(LR.getNumValNums());1339 1340 const VNInfo *used = nullptr, *unused = nullptr;1341 1342 // Determine connections.1343 for (const VNInfo *VNI : LR.valnos) {1344 // Group all unused values into one class.1345 if (VNI->isUnused()) {1346 if (unused)1347 EqClass.join(unused->id, VNI->id);1348 unused = VNI;1349 continue;1350 }1351 used = VNI;1352 if (VNI->isPHIDef()) {1353 const MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);1354 assert(MBB && "Phi-def has no defining MBB");1355 // Connect to values live out of predecessors.1356 for (MachineBasicBlock *Pred : MBB->predecessors())1357 if (const VNInfo *PVNI = LR.getVNInfoBefore(LIS.getMBBEndIdx(Pred)))1358 EqClass.join(VNI->id, PVNI->id);1359 } else {1360 // Normal value defined by an instruction. Check for two-addr redef.1361 // FIXME: This could be coincidental. Should we really check for a tied1362 // operand constraint?1363 // Note that VNI->def may be a use slot for an early clobber def.1364 if (const VNInfo *UVNI = LR.getVNInfoBefore(VNI->def))1365 EqClass.join(VNI->id, UVNI->id);1366 }1367 }1368 1369 // Lump all the unused values in with the last used value.1370 if (used && unused)1371 EqClass.join(used->id, unused->id);1372 1373 EqClass.compress();1374 return EqClass.getNumClasses();1375}1376 1377void ConnectedVNInfoEqClasses::Distribute(LiveInterval &LI, LiveInterval *LIV[],1378 MachineRegisterInfo &MRI) {1379 // Rewrite instructions.1380 for (MachineOperand &MO :1381 llvm::make_early_inc_range(MRI.reg_operands(LI.reg()))) {1382 MachineInstr *MI = MO.getParent();1383 const VNInfo *VNI;1384 if (MI->isDebugValue()) {1385 // DBG_VALUE instructions don't have slot indexes, so get the index of1386 // the instruction before them. The value is defined there too.1387 SlotIndex Idx = LIS.getSlotIndexes()->getIndexBefore(*MI);1388 VNI = LI.Query(Idx).valueOut();1389 } else {1390 SlotIndex Idx = LIS.getInstructionIndex(*MI);1391 LiveQueryResult LRQ = LI.Query(Idx);1392 VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();1393 }1394 // In the case of an <undef> use that isn't tied to any def, VNI will be1395 // NULL. If the use is tied to a def, VNI will be the defined value.1396 if (!VNI)1397 continue;1398 if (unsigned EqClass = getEqClass(VNI))1399 MO.setReg(LIV[EqClass - 1]->reg());1400 }1401 1402 // Distribute subregister liveranges.1403 if (LI.hasSubRanges()) {1404 unsigned NumComponents = EqClass.getNumClasses();1405 SmallVector<unsigned, 8> VNIMapping;1406 SmallVector<LiveInterval::SubRange*, 8> SubRanges;1407 BumpPtrAllocator &Allocator = LIS.getVNInfoAllocator();1408 for (LiveInterval::SubRange &SR : LI.subranges()) {1409 // Create new subranges in the split intervals and construct a mapping1410 // for the VNInfos in the subrange.1411 unsigned NumValNos = SR.valnos.size();1412 VNIMapping.clear();1413 VNIMapping.reserve(NumValNos);1414 SubRanges.clear();1415 SubRanges.resize(NumComponents-1, nullptr);1416 for (unsigned I = 0; I < NumValNos; ++I) {1417 const VNInfo &VNI = *SR.valnos[I];1418 unsigned ComponentNum;1419 if (VNI.isUnused()) {1420 ComponentNum = 0;1421 } else {1422 const VNInfo *MainRangeVNI = LI.getVNInfoAt(VNI.def);1423 assert(MainRangeVNI != nullptr1424 && "SubRange def must have corresponding main range def");1425 ComponentNum = getEqClass(MainRangeVNI);1426 if (ComponentNum > 0 && SubRanges[ComponentNum-1] == nullptr) {1427 SubRanges[ComponentNum-1]1428 = LIV[ComponentNum-1]->createSubRange(Allocator, SR.LaneMask);1429 }1430 }1431 VNIMapping.push_back(ComponentNum);1432 }1433 DistributeRange(SR, SubRanges.data(), VNIMapping);1434 }1435 LI.removeEmptySubRanges();1436 }1437 1438 // Distribute main liverange.1439 DistributeRange(LI, LIV, EqClass);1440}1441