X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FLiveInterval.cpp;h=bb3488348f24f08cb09fa7b03488dc09a390e185;hb=dcaeedf3f4b0fde4e5eb38cda5d463b7971a70a7;hp=2b8feb8c3b45b83f09995ab84b22ee3a0018002c;hpb=03d9609c6154ed91daefb4e4f89b7298c11961f3;p=oota-llvm.git diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp index 2b8feb8c3b4..bb3488348f2 100644 --- a/lib/CodeGen/LiveInterval.cpp +++ b/lib/CodeGen/LiveInterval.cpp @@ -31,6 +31,274 @@ #include using namespace llvm; +namespace { +//===----------------------------------------------------------------------===// +// Implementation of various methods necessary for calculation of live ranges. +// The implementation of the methods abstracts from the concrete type of the +// segment collection. +// +// Implementation of the class follows the Template design pattern. The base +// class contains generic algorithms that call collection-specific methods, +// which are provided in concrete subclasses. In order to avoid virtual calls +// these methods are provided by means of C++ template instantiation. +// The base class calls the methods of the subclass through method impl(), +// which casts 'this' pointer to the type of the subclass. +// +//===----------------------------------------------------------------------===// + +template +class CalcLiveRangeUtilBase { +protected: + LiveRange *LR; + +protected: + CalcLiveRangeUtilBase(LiveRange *LR) : LR(LR) {} + +public: + typedef LiveRange::Segment Segment; + typedef IteratorT iterator; + + VNInfo *createDeadDef(SlotIndex Def, VNInfo::Allocator &VNInfoAllocator) { + assert(!Def.isDead() && "Cannot define a value at the dead slot"); + + iterator I = impl().find(Def); + if (I == segments().end()) { + VNInfo *VNI = LR->getNextValue(Def, VNInfoAllocator); + impl().insertAtEnd(Segment(Def, Def.getDeadSlot(), VNI)); + return VNI; + } + + Segment *S = segmentAt(I); + if (SlotIndex::isSameInstr(Def, S->start)) { + assert(S->valno->def == S->start && "Inconsistent existing value def"); + + // It is possible to have both normal and early-clobber defs of the same + // register on an instruction. It doesn't make a lot of sense, but it is + // possible to specify in inline assembly. + // + // Just convert everything to early-clobber. + Def = std::min(Def, S->start); + if (Def != S->start) + S->start = S->valno->def = Def; + return S->valno; + } + assert(SlotIndex::isEarlierInstr(Def, S->start) && "Already live at def"); + VNInfo *VNI = LR->getNextValue(Def, VNInfoAllocator); + segments().insert(I, Segment(Def, Def.getDeadSlot(), VNI)); + return VNI; + } + + VNInfo *extendInBlock(SlotIndex StartIdx, SlotIndex Use) { + if (segments().empty()) + return nullptr; + iterator I = + impl().findInsertPos(Segment(Use.getPrevSlot(), Use, nullptr)); + if (I == segments().begin()) + return nullptr; + --I; + if (I->end <= StartIdx) + return nullptr; + if (I->end < Use) + extendSegmentEndTo(I, Use); + return I->valno; + } + + /// This method is used when we want to extend the segment specified + /// by I to end at the specified endpoint. To do this, we should + /// merge and eliminate all segments that this will overlap + /// with. The iterator is not invalidated. + void extendSegmentEndTo(iterator I, SlotIndex NewEnd) { + assert(I != segments().end() && "Not a valid segment!"); + Segment *S = segmentAt(I); + VNInfo *ValNo = I->valno; + + // Search for the first segment that we can't merge with. + iterator MergeTo = std::next(I); + for (; MergeTo != segments().end() && NewEnd >= MergeTo->end; ++MergeTo) + assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); + + // If NewEnd was in the middle of a segment, make sure to get its endpoint. + S->end = std::max(NewEnd, std::prev(MergeTo)->end); + + // If the newly formed segment now touches the segment after it and if they + // have the same value number, merge the two segments into one segment. + if (MergeTo != segments().end() && MergeTo->start <= I->end && + MergeTo->valno == ValNo) { + S->end = MergeTo->end; + ++MergeTo; + } + + // Erase any dead segments. + segments().erase(std::next(I), MergeTo); + } + + /// This method is used when we want to extend the segment specified + /// by I to start at the specified endpoint. To do this, we should + /// merge and eliminate all segments that this will overlap with. + iterator extendSegmentStartTo(iterator I, SlotIndex NewStart) { + assert(I != segments().end() && "Not a valid segment!"); + Segment *S = segmentAt(I); + VNInfo *ValNo = I->valno; + + // Search for the first segment that we can't merge with. + iterator MergeTo = I; + do { + if (MergeTo == segments().begin()) { + S->start = NewStart; + segments().erase(MergeTo, I); + return I; + } + assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); + --MergeTo; + } while (NewStart <= MergeTo->start); + + // If we start in the middle of another segment, just delete a range and + // extend that segment. + if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) { + segmentAt(MergeTo)->end = S->end; + } else { + // Otherwise, extend the segment right after. + ++MergeTo; + Segment *MergeToSeg = segmentAt(MergeTo); + MergeToSeg->start = NewStart; + MergeToSeg->end = S->end; + } + + segments().erase(std::next(MergeTo), std::next(I)); + return MergeTo; + } + + iterator addSegment(Segment S) { + SlotIndex Start = S.start, End = S.end; + iterator I = impl().findInsertPos(S); + + // If the inserted segment starts in the middle or right at the end of + // another segment, just extend that segment to contain the segment of S. + if (I != segments().begin()) { + iterator B = std::prev(I); + if (S.valno == B->valno) { + if (B->start <= Start && B->end >= Start) { + extendSegmentEndTo(B, End); + return B; + } + } else { + // Check to make sure that we are not overlapping two live segments with + // different valno's. + assert(B->end <= Start && + "Cannot overlap two segments with differing ValID's" + " (did you def the same reg twice in a MachineInstr?)"); + } + } + + // Otherwise, if this segment ends in the middle of, or right next + // to, another segment, merge it into that segment. + if (I != segments().end()) { + if (S.valno == I->valno) { + if (I->start <= End) { + I = extendSegmentStartTo(I, Start); + + // If S is a complete superset of a segment, we may need to grow its + // endpoint as well. + if (End > I->end) + extendSegmentEndTo(I, End); + return I; + } + } else { + // Check to make sure that we are not overlapping two live segments with + // different valno's. + assert(I->start >= End && + "Cannot overlap two segments with differing ValID's"); + } + } + + // Otherwise, this is just a new segment that doesn't interact with + // anything. + // Insert it. + return segments().insert(I, S); + } + +private: + ImplT &impl() { return *static_cast(this); } + + CollectionT &segments() { return impl().segmentsColl(); } + + Segment *segmentAt(iterator I) { return const_cast(&(*I)); } +}; + +//===----------------------------------------------------------------------===// +// Instantiation of the methods for calculation of live ranges +// based on a segment vector. +//===----------------------------------------------------------------------===// + +class CalcLiveRangeUtilVector; +typedef CalcLiveRangeUtilBase CalcLiveRangeUtilVectorBase; + +class CalcLiveRangeUtilVector : public CalcLiveRangeUtilVectorBase { +public: + CalcLiveRangeUtilVector(LiveRange *LR) : CalcLiveRangeUtilVectorBase(LR) {} + +private: + friend CalcLiveRangeUtilVectorBase; + + LiveRange::Segments &segmentsColl() { return LR->segments; } + + void insertAtEnd(const Segment &S) { LR->segments.push_back(S); } + + iterator find(SlotIndex Pos) { return LR->find(Pos); } + + iterator findInsertPos(Segment S) { + return std::upper_bound(LR->begin(), LR->end(), S.start); + } +}; + +//===----------------------------------------------------------------------===// +// Instantiation of the methods for calculation of live ranges +// based on a segment set. +//===----------------------------------------------------------------------===// + +class CalcLiveRangeUtilSet; +typedef CalcLiveRangeUtilBase CalcLiveRangeUtilSetBase; + +class CalcLiveRangeUtilSet : public CalcLiveRangeUtilSetBase { +public: + CalcLiveRangeUtilSet(LiveRange *LR) : CalcLiveRangeUtilSetBase(LR) {} + +private: + friend CalcLiveRangeUtilSetBase; + + LiveRange::SegmentSet &segmentsColl() { return *LR->segmentSet; } + + void insertAtEnd(const Segment &S) { + LR->segmentSet->insert(LR->segmentSet->end(), S); + } + + iterator find(SlotIndex Pos) { + iterator I = + LR->segmentSet->upper_bound(Segment(Pos, Pos.getNextSlot(), nullptr)); + if (I == LR->segmentSet->begin()) + return I; + iterator PrevI = std::prev(I); + if (Pos < (*PrevI).end) + return PrevI; + return I; + } + + iterator findInsertPos(Segment S) { + iterator I = LR->segmentSet->upper_bound(S); + if (I != LR->segmentSet->end() && !(S.start < *I)) + ++I; + return I; + } +}; +} // namespace + +//===----------------------------------------------------------------------===// +// LiveRange methods +//===----------------------------------------------------------------------===// + LiveRange::iterator LiveRange::find(SlotIndex Pos) { // This algorithm is basically std::upper_bound. // Unfortunately, std::upper_bound cannot be used with mixed types until we @@ -51,30 +319,11 @@ LiveRange::iterator LiveRange::find(SlotIndex Pos) { VNInfo *LiveRange::createDeadDef(SlotIndex Def, VNInfo::Allocator &VNInfoAllocator) { - assert(!Def.isDead() && "Cannot define a value at the dead slot"); - iterator I = find(Def); - if (I == end()) { - VNInfo *VNI = getNextValue(Def, VNInfoAllocator); - segments.push_back(Segment(Def, Def.getDeadSlot(), VNI)); - return VNI; - } - if (SlotIndex::isSameInstr(Def, I->start)) { - assert(I->valno->def == I->start && "Inconsistent existing value def"); - - // It is possible to have both normal and early-clobber defs of the same - // register on an instruction. It doesn't make a lot of sense, but it is - // possible to specify in inline assembly. - // - // Just convert everything to early-clobber. - Def = std::min(Def, I->start); - if (Def != I->start) - I->start = I->valno->def = Def; - return I->valno; - } - assert(SlotIndex::isEarlierInstr(Def, I->start) && "Already live at def"); - VNInfo *VNI = getNextValue(Def, VNInfoAllocator); - segments.insert(I, Segment(Def, Def.getDeadSlot(), VNI)); - return VNI; + // Use the segment set, if it is available. + if (segmentSet != nullptr) + return CalcLiveRangeUtilSet(this).createDeadDef(Def, VNInfoAllocator); + // Otherwise use the segment vector. + return CalcLiveRangeUtilVector(this).createDeadDef(Def, VNInfoAllocator); } // overlaps - Return true if the intersection of the two live ranges is @@ -185,6 +434,27 @@ bool LiveRange::overlaps(SlotIndex Start, SlotIndex End) const { return I != begin() && (--I)->end > Start; } +bool LiveRange::covers(const LiveRange &Other) const { + if (empty()) + return Other.empty(); + + const_iterator I = begin(); + for (const Segment &O : Other.segments) { + I = advanceTo(I, O.start); + if (I == end() || I->start > O.start) + return false; + + // Check adjacent live segments and see if we can get behind O.end. + while (I->end < O.end) { + const_iterator Last = I; + // Get next segment and abort if it was not adjacent. + ++I; + if (I == end() || Last->end != I->start) + return false; + } + } + return true; +} /// ValNo is dead, remove it. If it is the largest value number, just nuke it /// (and any other deleted values neighboring it), otherwise mark it as ~1U so @@ -204,9 +474,9 @@ void LiveRange::markValNoForDeletion(VNInfo *ValNo) { void LiveRange::RenumberValues() { SmallPtrSet Seen; valnos.clear(); - for (const_iterator I = begin(), E = end(); I != E; ++I) { - VNInfo *VNI = I->valno; - if (!Seen.insert(VNI)) + for (const Segment &S : segments) { + VNInfo *VNI = S.valno; + if (!Seen.insert(VNI).second) continue; assert(!VNI->isUnused() && "Unused valno used by live segment"); VNI->id = (unsigned)valnos.size(); @@ -214,133 +484,35 @@ void LiveRange::RenumberValues() { } } -/// This method is used when we want to extend the segment specified by I to end -/// at the specified endpoint. To do this, we should merge and eliminate all -/// segments that this will overlap with. The iterator is not invalidated. -void LiveRange::extendSegmentEndTo(iterator I, SlotIndex NewEnd) { - assert(I != end() && "Not a valid segment!"); - VNInfo *ValNo = I->valno; - - // Search for the first segment that we can't merge with. - iterator MergeTo = llvm::next(I); - for (; MergeTo != end() && NewEnd >= MergeTo->end; ++MergeTo) { - assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); - } - - // If NewEnd was in the middle of a segment, make sure to get its endpoint. - I->end = std::max(NewEnd, prior(MergeTo)->end); - - // If the newly formed segment now touches the segment after it and if they - // have the same value number, merge the two segments into one segment. - if (MergeTo != end() && MergeTo->start <= I->end && - MergeTo->valno == ValNo) { - I->end = MergeTo->end; - ++MergeTo; - } - - // Erase any dead segments. - segments.erase(llvm::next(I), MergeTo); +void LiveRange::addSegmentToSet(Segment S) { + CalcLiveRangeUtilSet(this).addSegment(S); } - -/// This method is used when we want to extend the segment specified by I to -/// start at the specified endpoint. To do this, we should merge and eliminate -/// all segments that this will overlap with. -LiveRange::iterator -LiveRange::extendSegmentStartTo(iterator I, SlotIndex NewStart) { - assert(I != end() && "Not a valid segment!"); - VNInfo *ValNo = I->valno; - - // Search for the first segment that we can't merge with. - iterator MergeTo = I; - do { - if (MergeTo == begin()) { - I->start = NewStart; - segments.erase(MergeTo, I); - return I; - } - assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); - --MergeTo; - } while (NewStart <= MergeTo->start); - - // If we start in the middle of another segment, just delete a range and - // extend that segment. - if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) { - MergeTo->end = I->end; - } else { - // Otherwise, extend the segment right after. - ++MergeTo; - MergeTo->start = NewStart; - MergeTo->end = I->end; +LiveRange::iterator LiveRange::addSegment(Segment S) { + // Use the segment set, if it is available. + if (segmentSet != nullptr) { + addSegmentToSet(S); + return end(); } - - segments.erase(llvm::next(MergeTo), llvm::next(I)); - return MergeTo; + // Otherwise use the segment vector. + return CalcLiveRangeUtilVector(this).addSegment(S); } -LiveRange::iterator LiveRange::addSegmentFrom(Segment S, iterator From) { - SlotIndex Start = S.start, End = S.end; - iterator it = std::upper_bound(From, end(), Start); - - // If the inserted segment starts in the middle or right at the end of - // another segment, just extend that segment to contain the segment of S. - if (it != begin()) { - iterator B = prior(it); - if (S.valno == B->valno) { - if (B->start <= Start && B->end >= Start) { - extendSegmentEndTo(B, End); - return B; - } - } else { - // Check to make sure that we are not overlapping two live segments with - // different valno's. - assert(B->end <= Start && - "Cannot overlap two segments with differing ValID's" - " (did you def the same reg twice in a MachineInstr?)"); - } - } - - // Otherwise, if this segment ends in the middle of, or right next to, another - // segment, merge it into that segment. - if (it != end()) { - if (S.valno == it->valno) { - if (it->start <= End) { - it = extendSegmentStartTo(it, Start); - - // If S is a complete superset of a segment, we may need to grow its - // endpoint as well. - if (End > it->end) - extendSegmentEndTo(it, End); - return it; - } - } else { - // Check to make sure that we are not overlapping two live segments with - // different valno's. - assert(it->start >= End && - "Cannot overlap two segments with differing ValID's"); - } - } - - // Otherwise, this is just a new segment that doesn't interact with anything. - // Insert it. - return segments.insert(it, S); +void LiveRange::append(const Segment S) { + // Check that the segment belongs to the back of the list. + assert(segments.empty() || segments.back().end <= S.start); + segments.push_back(S); } /// extendInBlock - If this range is live before Kill in the basic /// block that starts at StartIdx, extend it to be live up to Kill and return /// the value. If there is no live range before Kill, return NULL. VNInfo *LiveRange::extendInBlock(SlotIndex StartIdx, SlotIndex Kill) { - if (empty()) - return 0; - iterator I = std::upper_bound(begin(), end(), Kill.getPrevSlot()); - if (I == begin()) - return 0; - --I; - if (I->end <= StartIdx) - return 0; - if (I->end < Kill) - extendSegmentEndTo(I, Kill); - return I->valno; + // Use the segment set, if it is available. + if (segmentSet != nullptr) + return CalcLiveRangeUtilSet(this).extendInBlock(StartIdx, Kill); + // Otherwise use the segment vector. + return CalcLiveRangeUtilVector(this).extendInBlock(StartIdx, Kill); } /// Remove the specified segment from this range. Note that the segment must @@ -389,20 +561,16 @@ void LiveRange::removeSegment(SlotIndex Start, SlotIndex End, I->end = Start; // Trim the old segment. // Insert the new one. - segments.insert(llvm::next(I), Segment(End, OldEnd, ValNo)); + segments.insert(std::next(I), Segment(End, OldEnd, ValNo)); } /// removeValNo - Remove all the segments defined by the specified value#. /// Also remove the value# from value# list. void LiveRange::removeValNo(VNInfo *ValNo) { if (empty()) return; - iterator I = end(); - iterator E = begin(); - do { - --I; - if (I->valno == ValNo) - segments.erase(I); - } while (I != E); + segments.erase(std::remove_if(begin(), end(), [ValNo](const Segment &S) { + return S.valno == ValNo; + }), end()); // Now that ValNo is dead, remove it. markValNoForDeletion(ValNo); } @@ -433,9 +601,9 @@ void LiveRange::join(LiveRange &Other, iterator OutIt = begin(); OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]]; - for (iterator I = llvm::next(OutIt), E = end(); I != E; ++I) { + for (iterator I = std::next(OutIt), E = end(); I != E; ++I) { VNInfo* nextValNo = NewVNInfo[LHSValNoAssignments[I->valno->id]]; - assert(nextValNo != 0 && "Huh?"); + assert(nextValNo && "Huh?"); // If this live range has the same value # as its immediate predecessor, // and if they are neighbors, remove one Segment. This happens when we @@ -461,8 +629,8 @@ void LiveRange::join(LiveRange &Other, // This can leave Other in an invalid state because we're not coalescing // touching segments that now have identical values. That's OK since Other is // not supposed to be valid after calling join(); - for (iterator I = Other.begin(), E = Other.end(); I != E; ++I) - I->valno = NewVNInfo[RHSValNoAssignments[I->valno->id]]; + for (Segment &S : Other.segments) + S.valno = NewVNInfo[RHSValNoAssignments[S.valno->id]]; // Update val# info. Renumber them and make sure they all belong to this // LiveRange now. Also remove dead val#'s. @@ -482,8 +650,8 @@ void LiveRange::join(LiveRange &Other, // Okay, now insert the RHS live segments into the LHS. LiveRangeUpdater Updater(this); - for (iterator I = Other.begin(), E = Other.end(); I != E; ++I) - Updater.add(*I); + for (Segment &S : Other.segments) + Updater.add(S); } /// Merge all of the segments in RHS into this live range as the specified @@ -493,8 +661,8 @@ void LiveRange::join(LiveRange &Other, void LiveRange::MergeSegmentsInAsValue(const LiveRange &RHS, VNInfo *LHSValNo) { LiveRangeUpdater Updater(this); - for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) - Updater.add(I->start, I->end, LHSValNo); + for (const Segment &S : RHS.segments) + Updater.add(S.start, S.end, LHSValNo); } /// MergeValueInAsValue - Merge all of the live segments of a specific val# @@ -506,9 +674,9 @@ void LiveRange::MergeValueInAsValue(const LiveRange &RHS, const VNInfo *RHSValNo, VNInfo *LHSValNo) { LiveRangeUpdater Updater(this); - for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) - if (I->valno == RHSValNo) - Updater.add(I->start, I->end, LHSValNo); + for (const Segment &S : RHS.segments) + if (S.valno == RHSValNo) + Updater.add(S.start, S.end, LHSValNo); } /// MergeValueNumberInto - This method is called when two value nubmers @@ -570,10 +738,285 @@ VNInfo *LiveRange::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) { return V2; } +void LiveRange::flushSegmentSet() { + assert(segmentSet != nullptr && "segment set must have been created"); + assert( + segments.empty() && + "segment set can be used only initially before switching to the array"); + segments.append(segmentSet->begin(), segmentSet->end()); + segmentSet = nullptr; + verify(); +} + +void LiveInterval::freeSubRange(SubRange *S) { + S->~SubRange(); + // Memory was allocated with BumpPtr allocator and is not freed here. +} + +void LiveInterval::removeEmptySubRanges() { + SubRange **NextPtr = &SubRanges; + SubRange *I = *NextPtr; + while (I != nullptr) { + if (!I->empty()) { + NextPtr = &I->Next; + I = *NextPtr; + continue; + } + // Skip empty subranges until we find the first nonempty one. + do { + SubRange *Next = I->Next; + freeSubRange(I); + I = Next; + } while (I != nullptr && I->empty()); + *NextPtr = I; + } +} + +void LiveInterval::clearSubRanges() { + for (SubRange *I = SubRanges, *Next; I != nullptr; I = Next) { + Next = I->Next; + freeSubRange(I); + } + SubRanges = nullptr; +} + +/// Helper function for constructMainRangeFromSubranges(): Search the CFG +/// backwards until we find a place covered by a LiveRange segment that actually +/// has a valno set. +static VNInfo *searchForVNI(const SlotIndexes &Indexes, LiveRange &LR, + const MachineBasicBlock *MBB, + SmallPtrSetImpl &Visited) { + // We start the search at the end of MBB. + SlotIndex EndIdx = Indexes.getMBBEndIdx(MBB); + // In our use case we can't live the area covered by the live segments without + // finding an actual VNI def. + LiveRange::iterator I = LR.find(EndIdx.getPrevSlot()); + assert(I != LR.end()); + LiveRange::Segment &S = *I; + if (S.valno != nullptr) + return S.valno; + + VNInfo *VNI = nullptr; + // Continue at predecessors (we could even go to idom with domtree available). + for (const MachineBasicBlock *Pred : MBB->predecessors()) { + // Avoid going in circles. + if (!Visited.insert(Pred).second) + continue; + + VNI = searchForVNI(Indexes, LR, Pred, Visited); + if (VNI != nullptr) { + S.valno = VNI; + break; + } + } + + return VNI; +} + +static void determineMissingVNIs(const SlotIndexes &Indexes, LiveInterval &LI) { + SmallPtrSet Visited; + + LiveRange::iterator OutIt; + VNInfo *PrevValNo = nullptr; + for (LiveRange::iterator I = LI.begin(), E = LI.end(); I != E; ++I) { + LiveRange::Segment &S = *I; + // Determine final VNI if necessary. + if (S.valno == nullptr) { + // This can only happen at the begin of a basic block. + assert(S.start.isBlock() && "valno should only be missing at block begin"); + + Visited.clear(); + const MachineBasicBlock *MBB = Indexes.getMBBFromIndex(S.start); + for (const MachineBasicBlock *Pred : MBB->predecessors()) { + VNInfo *VNI = searchForVNI(Indexes, LI, Pred, Visited); + if (VNI != nullptr) { + S.valno = VNI; + break; + } + } + assert(S.valno != nullptr && "could not determine valno"); + } + // Merge with previous segment if it has the same VNI. + if (PrevValNo == S.valno && OutIt->end == S.start) { + OutIt->end = S.end; + } else { + // Didn't merge. Move OutIt to next segment. + if (PrevValNo == nullptr) + OutIt = LI.begin(); + else + ++OutIt; + + if (OutIt != I) + *OutIt = *I; + PrevValNo = S.valno; + } + } + // If we merged some segments chop off the end. + ++OutIt; + LI.segments.erase(OutIt, LI.end()); +} + +void LiveInterval::constructMainRangeFromSubranges( + const SlotIndexes &Indexes, VNInfo::Allocator &VNIAllocator) { + // The basic observations on which this algorithm is based: + // - Each Def/ValNo in a subrange must have a corresponding def on the main + // range, but not further defs/valnos are necessary. + // - If any of the subranges is live at a point the main liverange has to be + // live too, conversily if no subrange is live the main range mustn't be + // live either. + // We do this by scanning through all the subranges simultaneously creating new + // segments in the main range as segments start/ends come up in the subranges. + assert(hasSubRanges() && "expected subranges to be present"); + assert(segments.empty() && valnos.empty() && "expected empty main range"); + + // Collect subrange, iterator pairs for the walk and determine first and last + // SlotIndex involved. + SmallVector, 4> SRs; + SlotIndex First; + SlotIndex Last; + for (const SubRange &SR : subranges()) { + if (SR.empty()) + continue; + SRs.push_back(std::make_pair(&SR, SR.begin())); + if (!First.isValid() || SR.segments.front().start < First) + First = SR.segments.front().start; + if (!Last.isValid() || SR.segments.back().end > Last) + Last = SR.segments.back().end; + } + + // Walk over all subranges simultaneously. + Segment CurrentSegment; + bool ConstructingSegment = false; + bool NeedVNIFixup = false; + LaneBitmask ActiveMask = 0; + SlotIndex Pos = First; + while (true) { + SlotIndex NextPos = Last; + enum { + NOTHING, + BEGIN_SEGMENT, + END_SEGMENT, + } Event = NOTHING; + // Which subregister lanes are affected by the current event. + LaneBitmask EventMask = 0; + // Whether a BEGIN_SEGMENT is also a valno definition point. + bool IsDef = false; + // Find the next begin or end of a subrange segment. Combine masks if we + // have multiple begins/ends at the same position. Ends take precedence over + // Begins. + for (auto &SRP : SRs) { + const SubRange &SR = *SRP.first; + const_iterator &I = SRP.second; + // Advance iterator of subrange to a segment involving Pos; the earlier + // segments are already merged at this point. + while (I != SR.end() && + (I->end < Pos || + (I->end == Pos && (ActiveMask & SR.LaneMask) == 0))) + ++I; + if (I == SR.end()) + continue; + if ((ActiveMask & SR.LaneMask) == 0 && + Pos <= I->start && I->start <= NextPos) { + // Merge multiple begins at the same position. + if (I->start == NextPos && Event == BEGIN_SEGMENT) { + EventMask |= SR.LaneMask; + IsDef |= I->valno->def == I->start; + } else if (I->start < NextPos || Event != END_SEGMENT) { + Event = BEGIN_SEGMENT; + NextPos = I->start; + EventMask = SR.LaneMask; + IsDef = I->valno->def == I->start; + } + } + if ((ActiveMask & SR.LaneMask) != 0 && + Pos <= I->end && I->end <= NextPos) { + // Merge multiple ends at the same position. + if (I->end == NextPos && Event == END_SEGMENT) + EventMask |= SR.LaneMask; + else { + Event = END_SEGMENT; + NextPos = I->end; + EventMask = SR.LaneMask; + } + } + } + + // Advance scan position. + Pos = NextPos; + if (Event == BEGIN_SEGMENT) { + if (ConstructingSegment && IsDef) { + // Finish previous segment because we have to start a new one. + CurrentSegment.end = Pos; + append(CurrentSegment); + ConstructingSegment = false; + } + + // Start a new segment if necessary. + if (!ConstructingSegment) { + // Determine value number for the segment. + VNInfo *VNI; + if (IsDef) { + VNI = getNextValue(Pos, VNIAllocator); + } else { + // We have to reuse an existing value number, if we are lucky + // then we already passed one of the predecessor blocks and determined + // its value number (with blocks in reverse postorder this would be + // always true but we have no such guarantee). + assert(Pos.isBlock()); + const MachineBasicBlock *MBB = Indexes.getMBBFromIndex(Pos); + // See if any of the predecessor blocks has a lower number and a VNI + for (const MachineBasicBlock *Pred : MBB->predecessors()) { + SlotIndex PredEnd = Indexes.getMBBEndIdx(Pred); + VNI = getVNInfoBefore(PredEnd); + if (VNI != nullptr) + break; + } + // Def will come later: We have to do an extra fixup pass. + if (VNI == nullptr) + NeedVNIFixup = true; + } + + // In rare cases we can produce adjacent segments with the same value + // number (if they come from different subranges, but happen to have + // the same defining instruction). VNIFixup will fix those cases. + if (!empty() && segments.back().end == Pos && + segments.back().valno == VNI) + NeedVNIFixup = true; + CurrentSegment.start = Pos; + CurrentSegment.valno = VNI; + ConstructingSegment = true; + } + ActiveMask |= EventMask; + } else if (Event == END_SEGMENT) { + assert(ConstructingSegment); + // Finish segment if no lane is active anymore. + ActiveMask &= ~EventMask; + if (ActiveMask == 0) { + CurrentSegment.end = Pos; + append(CurrentSegment); + ConstructingSegment = false; + } + } else { + // We reached the end of the last subranges and can stop. + assert(Event == NOTHING); + break; + } + } + + // We might not be able to assign new valnos for all segments if the basic + // block containing the definition comes after a segment using the valno. + // Do a fixup pass for this uncommon case. + if (NeedVNIFixup) + determineMissingVNIs(Indexes, *this); + + assert(ActiveMask == 0 && !ConstructingSegment && "all segments ended"); + verify(); +} + unsigned LiveInterval::getSize() const { unsigned Sum = 0; - for (const_iterator I = begin(), E = end(); I != E; ++I) - Sum += I->start.distance(I->end); + for (const Segment &S : segments) + Sum += S.start.distance(S.end); return Sum; } @@ -591,9 +1034,9 @@ void LiveRange::print(raw_ostream &OS) const { if (empty()) OS << "EMPTY"; else { - for (const_iterator I = begin(), E = end(); I != E; ++I) { - OS << *I; - assert(I->valno == getValNumInfo(I->valno->id) && "Bad VNInfo"); + for (const Segment &S : segments) { + OS << S; + assert(S.valno == getValNumInfo(S.valno->id) && "Bad VNInfo"); } } @@ -620,6 +1063,10 @@ void LiveRange::print(raw_ostream &OS) const { void LiveInterval::print(raw_ostream &OS) const { OS << PrintReg(reg) << ' '; super::print(OS); + // Print subranges + for (const SubRange &SR : subranges()) { + OS << " L" << PrintLaneMask(SR.LaneMask) << ' ' << SR; + } } #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) @@ -638,16 +1085,38 @@ void LiveRange::verify() const { assert(I->start.isValid()); assert(I->end.isValid()); assert(I->start < I->end); - assert(I->valno != 0); + assert(I->valno != nullptr); assert(I->valno->id < valnos.size()); assert(I->valno == valnos[I->valno->id]); - if (llvm::next(I) != E) { - assert(I->end <= llvm::next(I)->start); - if (I->end == llvm::next(I)->start) - assert(I->valno != llvm::next(I)->valno); + if (std::next(I) != E) { + assert(I->end <= std::next(I)->start); + if (I->end == std::next(I)->start) + assert(I->valno != std::next(I)->valno); } } } + +void LiveInterval::verify(const MachineRegisterInfo *MRI) const { + super::verify(); + + // Make sure SubRanges are fine and LaneMasks are disjunct. + LaneBitmask Mask = 0; + LaneBitmask MaxMask = MRI != nullptr ? MRI->getMaxLaneMaskForVReg(reg) : ~0u; + for (const SubRange &SR : subranges()) { + // Subrange lanemask should be disjunct to any previous subrange masks. + assert((Mask & SR.LaneMask) == 0); + Mask |= SR.LaneMask; + + // subrange mask should not contained in maximum lane mask for the vreg. + assert((Mask & ~MaxMask) == 0); + // empty subranges must be removed. + assert(!SR.empty()); + + SR.verify(); + // Main liverange should cover subrange. + assert(covers(SR)); + } +} #endif @@ -692,14 +1161,14 @@ void LiveRangeUpdater::print(raw_ostream &OS) const { OS << " updater with gap = " << (ReadI - WriteI) << ", last start = " << LastStart << ":\n Area 1:"; - for (LiveRange::const_iterator I = LR->begin(); I != WriteI; ++I) - OS << ' ' << *I; + for (const auto &S : make_range(LR->begin(), WriteI)) + OS << ' ' << S; OS << "\n Spills:"; for (unsigned I = 0, E = Spills.size(); I != E; ++I) OS << ' ' << Spills[I]; OS << "\n Area 2:"; - for (LiveRange::const_iterator I = ReadI, E = LR->end(); I != E; ++I) - OS << ' ' << *I; + for (const auto &S : make_range(ReadI, LR->end())) + OS << ' ' << S; OS << '\n'; } @@ -723,6 +1192,13 @@ static inline bool coalescable(const LiveRange::Segment &A, void LiveRangeUpdater::add(LiveRange::Segment Seg) { assert(LR && "Cannot add to a null destination"); + // Fall back to the regular add method if the live range + // is using the segment set instead of the segment vector. + if (LR->segmentSet != nullptr) { + LR->addSegmentToSet(Seg); + return; + } + // Flush the state if Start moves backwards. if (!LastStart.isValid() || LastStart > Seg.start) { if (isDirty()) @@ -852,17 +1328,15 @@ void LiveRangeUpdater::flush() { LR->verify(); } -unsigned ConnectedVNInfoEqClasses::Classify(const LiveInterval *LI) { +unsigned ConnectedVNInfoEqClasses::Classify(const LiveRange &LR) { // Create initial equivalence classes. EqClass.clear(); - EqClass.grow(LI->getNumValNums()); + EqClass.grow(LR.getNumValNums()); - const VNInfo *used = 0, *unused = 0; + const VNInfo *used = nullptr, *unused = nullptr; // Determine connections. - for (LiveInterval::const_vni_iterator I = LI->vni_begin(), E = LI->vni_end(); - I != E; ++I) { - const VNInfo *VNI = *I; + for (const VNInfo *VNI : LR.valnos) { // Group all unused values into one class. if (VNI->isUnused()) { if (unused) @@ -877,14 +1351,14 @@ unsigned ConnectedVNInfoEqClasses::Classify(const LiveInterval *LI) { // Connect to values live out of predecessors. for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PE = MBB->pred_end(); PI != PE; ++PI) - if (const VNInfo *PVNI = LI->getVNInfoBefore(LIS.getMBBEndIdx(*PI))) + if (const VNInfo *PVNI = LR.getVNInfoBefore(LIS.getMBBEndIdx(*PI))) EqClass.join(VNI->id, PVNI->id); } else { // Normal value defined by an instruction. Check for two-addr redef. // FIXME: This could be coincidental. Should we really check for a tied // operand constraint? // Note that VNI->def may be a use slot for an early clobber def. - if (const VNInfo *UVNI = LI->getVNInfoBefore(VNI->def)) + if (const VNInfo *UVNI = LR.getVNInfoBefore(VNI->def)) EqClass.join(VNI->id, UVNI->id); } } @@ -897,16 +1371,47 @@ unsigned ConnectedVNInfoEqClasses::Classify(const LiveInterval *LI) { return EqClass.getNumClasses(); } -void ConnectedVNInfoEqClasses::Distribute(LiveInterval *LIV[], - MachineRegisterInfo &MRI) { - assert(LIV[0] && "LIV[0] must be set"); - LiveInterval &LI = *LIV[0]; +template +static void DistributeRange(LiveRangeT &LR, LiveRangeT *SplitLRs[], + EqClassesT VNIClasses) { + // Move segments to new intervals. + LiveRange::iterator J = LR.begin(), E = LR.end(); + while (J != E && VNIClasses[J->valno->id] == 0) + ++J; + for (LiveRange::iterator I = J; I != E; ++I) { + if (unsigned eq = VNIClasses[I->valno->id]) { + assert((SplitLRs[eq-1]->empty() || SplitLRs[eq-1]->expiredAt(I->start)) && + "New intervals should be empty"); + SplitLRs[eq-1]->segments.push_back(*I); + } else + *J++ = *I; + } + LR.segments.erase(J, E); + // Transfer VNInfos to their new owners and renumber them. + unsigned j = 0, e = LR.getNumValNums(); + while (j != e && VNIClasses[j] == 0) + ++j; + for (unsigned i = j; i != e; ++i) { + VNInfo *VNI = LR.getValNumInfo(i); + if (unsigned eq = VNIClasses[i]) { + VNI->id = SplitLRs[eq-1]->getNumValNums(); + SplitLRs[eq-1]->valnos.push_back(VNI); + } else { + VNI->id = j; + LR.valnos[j++] = VNI; + } + } + LR.valnos.resize(j); +} + +void ConnectedVNInfoEqClasses::Distribute(LiveInterval &LI, LiveInterval *LIV[], + MachineRegisterInfo &MRI) { // Rewrite instructions. for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(LI.reg), RE = MRI.reg_end(); RI != RE;) { - MachineOperand &MO = RI.getOperand(); - MachineInstr *MI = MO.getParent(); + MachineOperand &MO = *RI; + MachineInstr *MI = RI->getParent(); ++RI; // DBG_VALUE instructions don't have slot indexes, so get the index of the // instruction before them. @@ -923,36 +1428,41 @@ void ConnectedVNInfoEqClasses::Distribute(LiveInterval *LIV[], // NULL. If the use is tied to a def, VNI will be the defined value. if (!VNI) continue; - MO.setReg(LIV[getEqClass(VNI)]->reg); - } - - // Move runs to new intervals. - LiveInterval::iterator J = LI.begin(), E = LI.end(); - while (J != E && EqClass[J->valno->id] == 0) - ++J; - for (LiveInterval::iterator I = J; I != E; ++I) { - if (unsigned eq = EqClass[I->valno->id]) { - assert((LIV[eq]->empty() || LIV[eq]->expiredAt(I->start)) && - "New intervals should be empty"); - LIV[eq]->segments.push_back(*I); - } else - *J++ = *I; + if (unsigned EqClass = getEqClass(VNI)) + MO.setReg(LIV[EqClass-1]->reg); } - LI.segments.erase(J, E); - // Transfer VNInfos to their new owners and renumber them. - unsigned j = 0, e = LI.getNumValNums(); - while (j != e && EqClass[j] == 0) - ++j; - for (unsigned i = j; i != e; ++i) { - VNInfo *VNI = LI.getValNumInfo(i); - if (unsigned eq = EqClass[i]) { - VNI->id = LIV[eq]->getNumValNums(); - LIV[eq]->valnos.push_back(VNI); - } else { - VNI->id = j; - LI.valnos[j++] = VNI; + // Distribute subregister liveranges. + if (LI.hasSubRanges()) { + unsigned NumComponents = EqClass.getNumClasses(); + SmallVector VNIMapping; + SmallVector SubRanges; + BumpPtrAllocator &Allocator = LIS.getVNInfoAllocator(); + for (LiveInterval::SubRange &SR : LI.subranges()) { + // Create new subranges in the split intervals and construct a mapping + // for the VNInfos in the subrange. + unsigned NumValNos = SR.valnos.size(); + VNIMapping.clear(); + VNIMapping.reserve(NumValNos); + SubRanges.clear(); + SubRanges.resize(NumComponents-1, nullptr); + for (unsigned I = 0; I < NumValNos; ++I) { + const VNInfo &VNI = *SR.valnos[I]; + const VNInfo *MainRangeVNI = LI.getVNInfoAt(VNI.def); + assert(MainRangeVNI != nullptr + && "SubRange def must have corresponding main range def"); + unsigned ComponentNum = getEqClass(MainRangeVNI); + VNIMapping.push_back(ComponentNum); + if (ComponentNum > 0 && SubRanges[ComponentNum-1] == nullptr) { + SubRanges[ComponentNum-1] + = LIV[ComponentNum-1]->createSubRange(Allocator, SR.LaneMask); + } + } + DistributeRange(SR, SubRanges.data(), VNIMapping); } + LI.removeEmptySubRanges(); } - LI.valnos.resize(j); + + // Distribute main liverange. + DistributeRange(LI, LIV, EqClass); }