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Diffstat (limited to 'contrib/llvm/lib/CodeGen/LiveInterval.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/LiveInterval.cpp | 886 |
1 files changed, 886 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/LiveInterval.cpp b/contrib/llvm/lib/CodeGen/LiveInterval.cpp new file mode 100644 index 000000000000..59f380ad2641 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/LiveInterval.cpp @@ -0,0 +1,886 @@ +//===-- LiveInterval.cpp - Live Interval Representation -------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the LiveRange and LiveInterval classes. Given some +// numbering of each the machine instructions an interval [i, j) is said to be a +// live interval for register v if there is no instruction with number j' > j +// such that v is live at j' and there is no instruction with number i' < i such +// that v is live at i'. In this implementation intervals can have holes, +// i.e. an interval might look like [1,20), [50,65), [1000,1001). Each +// individual range is represented as an instance of LiveRange, and the whole +// interval is represented as an instance of LiveInterval. +// +//===----------------------------------------------------------------------===// + +#include "llvm/CodeGen/LiveInterval.h" +#include "llvm/CodeGen/LiveIntervalAnalysis.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/SmallSet.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include <algorithm> +using namespace llvm; + +// An example for liveAt(): +// +// this = [1,4), liveAt(0) will return false. The instruction defining this +// spans slots [0,3]. The interval belongs to an spilled definition of the +// variable it represents. This is because slot 1 is used (def slot) and spans +// up to slot 3 (store slot). +// +bool LiveInterval::liveAt(SlotIndex I) const { + Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I); + + if (r == ranges.begin()) + return false; + + --r; + return r->contains(I); +} + +// liveBeforeAndAt - Check if the interval is live at the index and the index +// just before it. If index is liveAt, check if it starts a new live range. +// If it does, then check if the previous live range ends at index-1. +bool LiveInterval::liveBeforeAndAt(SlotIndex I) const { + Ranges::const_iterator r = std::upper_bound(ranges.begin(), ranges.end(), I); + + if (r == ranges.begin()) + return false; + + --r; + if (!r->contains(I)) + return false; + if (I != r->start) + return true; + // I is the start of a live range. Check if the previous live range ends + // at I-1. + if (r == ranges.begin()) + return false; + return r->end == I; +} + +/// killedAt - Return true if a live range ends at index. Note that the kill +/// point is not contained in the half-open live range. It is usually the +/// getDefIndex() slot following its last use. +bool LiveInterval::killedAt(SlotIndex I) const { + Ranges::const_iterator r = std::lower_bound(ranges.begin(), ranges.end(), I); + + // Now r points to the first interval with start >= I, or ranges.end(). + if (r == ranges.begin()) + return false; + + --r; + // Now r points to the last interval with end <= I. + // r->end is the kill point. + return r->end == I; +} + +/// killedInRange - Return true if the interval has kills in [Start,End). +bool LiveInterval::killedInRange(SlotIndex Start, SlotIndex End) const { + Ranges::const_iterator r = + std::lower_bound(ranges.begin(), ranges.end(), End); + + // Now r points to the first interval with start >= End, or ranges.end(). + if (r == ranges.begin()) + return false; + + --r; + // Now r points to the last interval with end <= End. + // r->end is the kill point. + return r->end >= Start && r->end < End; +} + +// overlaps - Return true if the intersection of the two live intervals is +// not empty. +// +// An example for overlaps(): +// +// 0: A = ... +// 4: B = ... +// 8: C = A + B ;; last use of A +// +// The live intervals should look like: +// +// A = [3, 11) +// B = [7, x) +// C = [11, y) +// +// A->overlaps(C) should return false since we want to be able to join +// A and C. +// +bool LiveInterval::overlapsFrom(const LiveInterval& other, + const_iterator StartPos) const { + assert(!empty() && "empty interval"); + const_iterator i = begin(); + const_iterator ie = end(); + const_iterator j = StartPos; + const_iterator je = other.end(); + + assert((StartPos->start <= i->start || StartPos == other.begin()) && + StartPos != other.end() && "Bogus start position hint!"); + + if (i->start < j->start) { + i = std::upper_bound(i, ie, j->start); + if (i != ranges.begin()) --i; + } else if (j->start < i->start) { + ++StartPos; + if (StartPos != other.end() && StartPos->start <= i->start) { + assert(StartPos < other.end() && i < end()); + j = std::upper_bound(j, je, i->start); + if (j != other.ranges.begin()) --j; + } + } else { + return true; + } + + if (j == je) return false; + + while (i != ie) { + if (i->start > j->start) { + std::swap(i, j); + std::swap(ie, je); + } + + if (i->end > j->start) + return true; + ++i; + } + + return false; +} + +/// overlaps - Return true if the live interval overlaps a range specified +/// by [Start, End). +bool LiveInterval::overlaps(SlotIndex Start, SlotIndex End) const { + assert(Start < End && "Invalid range"); + const_iterator I = std::lower_bound(begin(), end(), End); + return I != begin() && (--I)->end > Start; +} + + +/// 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 +/// it can be nuked later. +void LiveInterval::markValNoForDeletion(VNInfo *ValNo) { + if (ValNo->id == getNumValNums()-1) { + do { + valnos.pop_back(); + } while (!valnos.empty() && valnos.back()->isUnused()); + } else { + ValNo->setIsUnused(true); + } +} + +/// RenumberValues - Renumber all values in order of appearance and delete the +/// remaining unused values. +void LiveInterval::RenumberValues(LiveIntervals &lis) { + SmallPtrSet<VNInfo*, 8> Seen; + bool seenPHIDef = false; + valnos.clear(); + for (const_iterator I = begin(), E = end(); I != E; ++I) { + VNInfo *VNI = I->valno; + if (!Seen.insert(VNI)) + continue; + assert(!VNI->isUnused() && "Unused valno used by live range"); + VNI->id = (unsigned)valnos.size(); + valnos.push_back(VNI); + VNI->setHasPHIKill(false); + if (VNI->isPHIDef()) + seenPHIDef = true; + } + + // Recompute phi kill flags. + if (!seenPHIDef) + return; + for (const_vni_iterator I = vni_begin(), E = vni_end(); I != E; ++I) { + VNInfo *VNI = *I; + if (!VNI->isPHIDef()) + continue; + const MachineBasicBlock *PHIBB = lis.getMBBFromIndex(VNI->def); + assert(PHIBB && "No basic block for phi-def"); + for (MachineBasicBlock::const_pred_iterator PI = PHIBB->pred_begin(), + PE = PHIBB->pred_end(); PI != PE; ++PI) { + VNInfo *KVNI = getVNInfoAt(lis.getMBBEndIdx(*PI).getPrevSlot()); + if (KVNI) + KVNI->setHasPHIKill(true); + } + } +} + +/// extendIntervalEndTo - This method is used when we want to extend the range +/// specified by I to end at the specified endpoint. To do this, we should +/// merge and eliminate all ranges that this will overlap with. The iterator is +/// not invalidated. +void LiveInterval::extendIntervalEndTo(Ranges::iterator I, SlotIndex NewEnd) { + assert(I != ranges.end() && "Not a valid interval!"); + VNInfo *ValNo = I->valno; + + // Search for the first interval that we can't merge with. + Ranges::iterator MergeTo = llvm::next(I); + for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) { + assert(MergeTo->valno == ValNo && "Cannot merge with differing values!"); + } + + // If NewEnd was in the middle of an interval, make sure to get its endpoint. + I->end = std::max(NewEnd, prior(MergeTo)->end); + + // Erase any dead ranges. + ranges.erase(llvm::next(I), MergeTo); + + // If the newly formed range now touches the range after it and if they have + // the same value number, merge the two ranges into one range. + Ranges::iterator Next = llvm::next(I); + if (Next != ranges.end() && Next->start <= I->end && Next->valno == ValNo) { + I->end = Next->end; + ranges.erase(Next); + } +} + + +/// extendIntervalStartTo - This method is used when we want to extend the range +/// specified by I to start at the specified endpoint. To do this, we should +/// merge and eliminate all ranges that this will overlap with. +LiveInterval::Ranges::iterator +LiveInterval::extendIntervalStartTo(Ranges::iterator I, SlotIndex NewStart) { + assert(I != ranges.end() && "Not a valid interval!"); + VNInfo *ValNo = I->valno; + + // Search for the first interval that we can't merge with. + Ranges::iterator MergeTo = I; + do { + if (MergeTo == ranges.begin()) { + I->start = NewStart; + ranges.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 interval, just delete a range and + // extend that interval. + if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) { + MergeTo->end = I->end; + } else { + // Otherwise, extend the interval right after. + ++MergeTo; + MergeTo->start = NewStart; + MergeTo->end = I->end; + } + + ranges.erase(llvm::next(MergeTo), llvm::next(I)); + return MergeTo; +} + +LiveInterval::iterator +LiveInterval::addRangeFrom(LiveRange LR, iterator From) { + SlotIndex Start = LR.start, End = LR.end; + iterator it = std::upper_bound(From, ranges.end(), Start); + + // If the inserted interval starts in the middle or right at the end of + // another interval, just extend that interval to contain the range of LR. + if (it != ranges.begin()) { + iterator B = prior(it); + if (LR.valno == B->valno) { + if (B->start <= Start && B->end >= Start) { + extendIntervalEndTo(B, End); + return B; + } + } else { + // Check to make sure that we are not overlapping two live ranges with + // different valno's. + assert(B->end <= Start && + "Cannot overlap two LiveRanges with differing ValID's" + " (did you def the same reg twice in a MachineInstr?)"); + } + } + + // Otherwise, if this range ends in the middle of, or right next to, another + // interval, merge it into that interval. + if (it != ranges.end()) { + if (LR.valno == it->valno) { + if (it->start <= End) { + it = extendIntervalStartTo(it, Start); + + // If LR is a complete superset of an interval, we may need to grow its + // endpoint as well. + if (End > it->end) + extendIntervalEndTo(it, End); + return it; + } + } else { + // Check to make sure that we are not overlapping two live ranges with + // different valno's. + assert(it->start >= End && + "Cannot overlap two LiveRanges with differing ValID's"); + } + } + + // Otherwise, this is just a new range that doesn't interact with anything. + // Insert it. + return ranges.insert(it, LR); +} + +/// isInOneLiveRange - Return true if the range specified is entirely in +/// a single LiveRange of the live interval. +bool LiveInterval::isInOneLiveRange(SlotIndex Start, SlotIndex End) { + Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start); + if (I == ranges.begin()) + return false; + --I; + return I->containsRange(Start, End); +} + + +/// removeRange - Remove the specified range from this interval. Note that +/// the range must be in a single LiveRange in its entirety. +void LiveInterval::removeRange(SlotIndex Start, SlotIndex End, + bool RemoveDeadValNo) { + // Find the LiveRange containing this span. + Ranges::iterator I = std::upper_bound(ranges.begin(), ranges.end(), Start); + assert(I != ranges.begin() && "Range is not in interval!"); + --I; + assert(I->containsRange(Start, End) && "Range is not entirely in interval!"); + + // If the span we are removing is at the start of the LiveRange, adjust it. + VNInfo *ValNo = I->valno; + if (I->start == Start) { + if (I->end == End) { + if (RemoveDeadValNo) { + // Check if val# is dead. + bool isDead = true; + for (const_iterator II = begin(), EE = end(); II != EE; ++II) + if (II != I && II->valno == ValNo) { + isDead = false; + break; + } + if (isDead) { + // Now that ValNo is dead, remove it. + markValNoForDeletion(ValNo); + } + } + + ranges.erase(I); // Removed the whole LiveRange. + } else + I->start = End; + return; + } + + // Otherwise if the span we are removing is at the end of the LiveRange, + // adjust the other way. + if (I->end == End) { + I->end = Start; + return; + } + + // Otherwise, we are splitting the LiveRange into two pieces. + SlotIndex OldEnd = I->end; + I->end = Start; // Trim the old interval. + + // Insert the new one. + ranges.insert(llvm::next(I), LiveRange(End, OldEnd, ValNo)); +} + +/// removeValNo - Remove all the ranges defined by the specified value#. +/// Also remove the value# from value# list. +void LiveInterval::removeValNo(VNInfo *ValNo) { + if (empty()) return; + Ranges::iterator I = ranges.end(); + Ranges::iterator E = ranges.begin(); + do { + --I; + if (I->valno == ValNo) + ranges.erase(I); + } while (I != E); + // Now that ValNo is dead, remove it. + markValNoForDeletion(ValNo); +} + +/// getLiveRangeContaining - Return the live range that contains the +/// specified index, or null if there is none. +LiveInterval::const_iterator +LiveInterval::FindLiveRangeContaining(SlotIndex Idx) const { + const_iterator It = std::upper_bound(begin(), end(), Idx); + if (It != ranges.begin()) { + --It; + if (It->contains(Idx)) + return It; + } + + return end(); +} + +LiveInterval::iterator +LiveInterval::FindLiveRangeContaining(SlotIndex Idx) { + iterator It = std::upper_bound(begin(), end(), Idx); + if (It != begin()) { + --It; + if (It->contains(Idx)) + return It; + } + + return end(); +} + +/// findDefinedVNInfo - Find the VNInfo defined by the specified +/// index (register interval). +VNInfo *LiveInterval::findDefinedVNInfoForRegInt(SlotIndex Idx) const { + for (LiveInterval::const_vni_iterator i = vni_begin(), e = vni_end(); + i != e; ++i) { + if ((*i)->def == Idx) + return *i; + } + + return 0; +} + +/// findDefinedVNInfo - Find the VNInfo defined by the specified +/// register (stack inteval). +VNInfo *LiveInterval::findDefinedVNInfoForStackInt(unsigned reg) const { + for (LiveInterval::const_vni_iterator i = vni_begin(), e = vni_end(); + i != e; ++i) { + if ((*i)->getReg() == reg) + return *i; + } + return 0; +} + +/// join - Join two live intervals (this, and other) together. This applies +/// mappings to the value numbers in the LHS/RHS intervals as specified. If +/// the intervals are not joinable, this aborts. +void LiveInterval::join(LiveInterval &Other, + const int *LHSValNoAssignments, + const int *RHSValNoAssignments, + SmallVector<VNInfo*, 16> &NewVNInfo, + MachineRegisterInfo *MRI) { + // Determine if any of our live range values are mapped. This is uncommon, so + // we want to avoid the interval scan if not. + bool MustMapCurValNos = false; + unsigned NumVals = getNumValNums(); + unsigned NumNewVals = NewVNInfo.size(); + for (unsigned i = 0; i != NumVals; ++i) { + unsigned LHSValID = LHSValNoAssignments[i]; + if (i != LHSValID || + (NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) + MustMapCurValNos = true; + } + + // If we have to apply a mapping to our base interval assignment, rewrite it + // now. + if (MustMapCurValNos) { + // Map the first live range. + iterator OutIt = begin(); + OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]]; + ++OutIt; + for (iterator I = OutIt, E = end(); I != E; ++I) { + OutIt->valno = NewVNInfo[LHSValNoAssignments[I->valno->id]]; + + // If this live range has the same value # as its immediate predecessor, + // and if they are neighbors, remove one LiveRange. This happens when we + // have [0,3:0)[4,7:1) and map 0/1 onto the same value #. + if (OutIt->valno == (OutIt-1)->valno && (OutIt-1)->end == OutIt->start) { + (OutIt-1)->end = OutIt->end; + } else { + if (I != OutIt) { + OutIt->start = I->start; + OutIt->end = I->end; + } + + // Didn't merge, on to the next one. + ++OutIt; + } + } + + // If we merge some live ranges, chop off the end. + ranges.erase(OutIt, end()); + } + + // Remember assignements because val# ids are changing. + SmallVector<unsigned, 16> OtherAssignments; + for (iterator I = Other.begin(), E = Other.end(); I != E; ++I) + OtherAssignments.push_back(RHSValNoAssignments[I->valno->id]); + + // Update val# info. Renumber them and make sure they all belong to this + // LiveInterval now. Also remove dead val#'s. + unsigned NumValNos = 0; + for (unsigned i = 0; i < NumNewVals; ++i) { + VNInfo *VNI = NewVNInfo[i]; + if (VNI) { + if (NumValNos >= NumVals) + valnos.push_back(VNI); + else + valnos[NumValNos] = VNI; + VNI->id = NumValNos++; // Renumber val#. + } + } + if (NumNewVals < NumVals) + valnos.resize(NumNewVals); // shrinkify + + // Okay, now insert the RHS live ranges into the LHS. + iterator InsertPos = begin(); + unsigned RangeNo = 0; + for (iterator I = Other.begin(), E = Other.end(); I != E; ++I, ++RangeNo) { + // Map the valno in the other live range to the current live range. + I->valno = NewVNInfo[OtherAssignments[RangeNo]]; + assert(I->valno && "Adding a dead range?"); + InsertPos = addRangeFrom(*I, InsertPos); + } + + ComputeJoinedWeight(Other); +} + +/// MergeRangesInAsValue - Merge all of the intervals in RHS into this live +/// interval as the specified value number. The LiveRanges in RHS are +/// allowed to overlap with LiveRanges in the current interval, but only if +/// the overlapping LiveRanges have the specified value number. +void LiveInterval::MergeRangesInAsValue(const LiveInterval &RHS, + VNInfo *LHSValNo) { + // TODO: Make this more efficient. + iterator InsertPos = begin(); + for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) { + // Map the valno in the other live range to the current live range. + LiveRange Tmp = *I; + Tmp.valno = LHSValNo; + InsertPos = addRangeFrom(Tmp, InsertPos); + } +} + + +/// MergeValueInAsValue - Merge all of the live ranges of a specific val# +/// in RHS into this live interval as the specified value number. +/// The LiveRanges in RHS are allowed to overlap with LiveRanges in the +/// current interval, it will replace the value numbers of the overlaped +/// live ranges with the specified value number. +void LiveInterval::MergeValueInAsValue( + const LiveInterval &RHS, + const VNInfo *RHSValNo, VNInfo *LHSValNo) { + SmallVector<VNInfo*, 4> ReplacedValNos; + iterator IP = begin(); + for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) { + assert(I->valno == RHS.getValNumInfo(I->valno->id) && "Bad VNInfo"); + if (I->valno != RHSValNo) + continue; + SlotIndex Start = I->start, End = I->end; + IP = std::upper_bound(IP, end(), Start); + // If the start of this range overlaps with an existing liverange, trim it. + if (IP != begin() && IP[-1].end > Start) { + if (IP[-1].valno != LHSValNo) { + ReplacedValNos.push_back(IP[-1].valno); + IP[-1].valno = LHSValNo; // Update val#. + } + Start = IP[-1].end; + // Trimmed away the whole range? + if (Start >= End) continue; + } + // If the end of this range overlaps with an existing liverange, trim it. + if (IP != end() && End > IP->start) { + if (IP->valno != LHSValNo) { + ReplacedValNos.push_back(IP->valno); + IP->valno = LHSValNo; // Update val#. + } + End = IP->start; + // If this trimmed away the whole range, ignore it. + if (Start == End) continue; + } + + // Map the valno in the other live range to the current live range. + IP = addRangeFrom(LiveRange(Start, End, LHSValNo), IP); + } + + + SmallSet<VNInfo*, 4> Seen; + for (unsigned i = 0, e = ReplacedValNos.size(); i != e; ++i) { + VNInfo *V1 = ReplacedValNos[i]; + if (Seen.insert(V1)) { + bool isDead = true; + for (const_iterator I = begin(), E = end(); I != E; ++I) + if (I->valno == V1) { + isDead = false; + break; + } + if (isDead) { + // Now that V1 is dead, remove it. + markValNoForDeletion(V1); + } + } + } +} + + +/// MergeInClobberRanges - For any live ranges that are not defined in the +/// current interval, but are defined in the Clobbers interval, mark them +/// used with an unknown definition value. +void LiveInterval::MergeInClobberRanges(LiveIntervals &li_, + const LiveInterval &Clobbers, + VNInfo::Allocator &VNInfoAllocator) { + if (Clobbers.empty()) return; + + DenseMap<VNInfo*, VNInfo*> ValNoMaps; + VNInfo *UnusedValNo = 0; + iterator IP = begin(); + for (const_iterator I = Clobbers.begin(), E = Clobbers.end(); I != E; ++I) { + // For every val# in the Clobbers interval, create a new "unknown" val#. + VNInfo *ClobberValNo = 0; + DenseMap<VNInfo*, VNInfo*>::iterator VI = ValNoMaps.find(I->valno); + if (VI != ValNoMaps.end()) + ClobberValNo = VI->second; + else if (UnusedValNo) + ClobberValNo = UnusedValNo; + else { + UnusedValNo = ClobberValNo = + getNextValue(li_.getInvalidIndex(), 0, false, VNInfoAllocator); + ValNoMaps.insert(std::make_pair(I->valno, ClobberValNo)); + } + + bool Done = false; + SlotIndex Start = I->start, End = I->end; + // If a clobber range starts before an existing range and ends after + // it, the clobber range will need to be split into multiple ranges. + // Loop until the entire clobber range is handled. + while (!Done) { + Done = true; + IP = std::upper_bound(IP, end(), Start); + SlotIndex SubRangeStart = Start; + SlotIndex SubRangeEnd = End; + + // If the start of this range overlaps with an existing liverange, trim it. + if (IP != begin() && IP[-1].end > SubRangeStart) { + SubRangeStart = IP[-1].end; + // Trimmed away the whole range? + if (SubRangeStart >= SubRangeEnd) continue; + } + // If the end of this range overlaps with an existing liverange, trim it. + if (IP != end() && SubRangeEnd > IP->start) { + // If the clobber live range extends beyond the existing live range, + // it'll need at least another live range, so set the flag to keep + // iterating. + if (SubRangeEnd > IP->end) { + Start = IP->end; + Done = false; + } + SubRangeEnd = IP->start; + // If this trimmed away the whole range, ignore it. + if (SubRangeStart == SubRangeEnd) continue; + } + + // Insert the clobber interval. + IP = addRangeFrom(LiveRange(SubRangeStart, SubRangeEnd, ClobberValNo), + IP); + UnusedValNo = 0; + } + } + + if (UnusedValNo) { + // Delete the last unused val#. + valnos.pop_back(); + } +} + +void LiveInterval::MergeInClobberRange(LiveIntervals &li_, + SlotIndex Start, + SlotIndex End, + VNInfo::Allocator &VNInfoAllocator) { + // Find a value # to use for the clobber ranges. If there is already a value# + // for unknown values, use it. + VNInfo *ClobberValNo = + getNextValue(li_.getInvalidIndex(), 0, false, VNInfoAllocator); + + iterator IP = begin(); + IP = std::upper_bound(IP, end(), Start); + + // If the start of this range overlaps with an existing liverange, trim it. + if (IP != begin() && IP[-1].end > Start) { + Start = IP[-1].end; + // Trimmed away the whole range? + if (Start >= End) return; + } + // If the end of this range overlaps with an existing liverange, trim it. + if (IP != end() && End > IP->start) { + End = IP->start; + // If this trimmed away the whole range, ignore it. + if (Start == End) return; + } + + // Insert the clobber interval. + addRangeFrom(LiveRange(Start, End, ClobberValNo), IP); +} + +/// MergeValueNumberInto - This method is called when two value nubmers +/// are found to be equivalent. This eliminates V1, replacing all +/// LiveRanges with the V1 value number with the V2 value number. This can +/// cause merging of V1/V2 values numbers and compaction of the value space. +VNInfo* LiveInterval::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) { + assert(V1 != V2 && "Identical value#'s are always equivalent!"); + + // This code actually merges the (numerically) larger value number into the + // smaller value number, which is likely to allow us to compactify the value + // space. The only thing we have to be careful of is to preserve the + // instruction that defines the result value. + + // Make sure V2 is smaller than V1. + if (V1->id < V2->id) { + V1->copyFrom(*V2); + std::swap(V1, V2); + } + + // Merge V1 live ranges into V2. + for (iterator I = begin(); I != end(); ) { + iterator LR = I++; + if (LR->valno != V1) continue; // Not a V1 LiveRange. + + // Okay, we found a V1 live range. If it had a previous, touching, V2 live + // range, extend it. + if (LR != begin()) { + iterator Prev = LR-1; + if (Prev->valno == V2 && Prev->end == LR->start) { + Prev->end = LR->end; + + // Erase this live-range. + ranges.erase(LR); + I = Prev+1; + LR = Prev; + } + } + + // Okay, now we have a V1 or V2 live range that is maximally merged forward. + // Ensure that it is a V2 live-range. + LR->valno = V2; + + // If we can merge it into later V2 live ranges, do so now. We ignore any + // following V1 live ranges, as they will be merged in subsequent iterations + // of the loop. + if (I != end()) { + if (I->start == LR->end && I->valno == V2) { + LR->end = I->end; + ranges.erase(I); + I = LR+1; + } + } + } + + // Now that V1 is dead, remove it. + markValNoForDeletion(V1); + + return V2; +} + +void LiveInterval::Copy(const LiveInterval &RHS, + MachineRegisterInfo *MRI, + VNInfo::Allocator &VNInfoAllocator) { + ranges.clear(); + valnos.clear(); + std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(RHS.reg); + MRI->setRegAllocationHint(reg, Hint.first, Hint.second); + + weight = RHS.weight; + for (unsigned i = 0, e = RHS.getNumValNums(); i != e; ++i) { + const VNInfo *VNI = RHS.getValNumInfo(i); + createValueCopy(VNI, VNInfoAllocator); + } + for (unsigned i = 0, e = RHS.ranges.size(); i != e; ++i) { + const LiveRange &LR = RHS.ranges[i]; + addRange(LiveRange(LR.start, LR.end, getValNumInfo(LR.valno->id))); + } +} + +unsigned LiveInterval::getSize() const { + unsigned Sum = 0; + for (const_iterator I = begin(), E = end(); I != E; ++I) + Sum += I->start.distance(I->end); + return Sum; +} + +/// ComputeJoinedWeight - Set the weight of a live interval Joined +/// after Other has been merged into it. +void LiveInterval::ComputeJoinedWeight(const LiveInterval &Other) { + // If either of these intervals was spilled, the weight is the + // weight of the non-spilled interval. This can only happen with + // iterative coalescers. + + if (Other.weight != HUGE_VALF) { + weight += Other.weight; + } + else if (weight == HUGE_VALF && + !TargetRegisterInfo::isPhysicalRegister(reg)) { + // Remove this assert if you have an iterative coalescer + assert(0 && "Joining to spilled interval"); + weight = Other.weight; + } + else { + // Otherwise the weight stays the same + // Remove this assert if you have an iterative coalescer + assert(0 && "Joining from spilled interval"); + } +} + +raw_ostream& llvm::operator<<(raw_ostream& os, const LiveRange &LR) { + return os << '[' << LR.start << ',' << LR.end << ':' << LR.valno->id << ")"; +} + +void LiveRange::dump() const { + dbgs() << *this << "\n"; +} + +void LiveInterval::print(raw_ostream &OS, const TargetRegisterInfo *TRI) const { + if (isStackSlot()) + OS << "SS#" << getStackSlotIndex(); + else if (TRI && TargetRegisterInfo::isPhysicalRegister(reg)) + OS << TRI->getName(reg); + else + OS << "%reg" << reg; + + OS << ',' << weight; + + if (empty()) + OS << " EMPTY"; + else { + OS << " = "; + for (LiveInterval::Ranges::const_iterator I = ranges.begin(), + E = ranges.end(); I != E; ++I) { + OS << *I; + assert(I->valno == getValNumInfo(I->valno->id) && "Bad VNInfo"); + } + } + + // Print value number info. + if (getNumValNums()) { + OS << " "; + unsigned vnum = 0; + for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e; + ++i, ++vnum) { + const VNInfo *vni = *i; + if (vnum) OS << " "; + OS << vnum << "@"; + if (vni->isUnused()) { + OS << "x"; + } else { + if (!vni->isDefAccurate() && !vni->isPHIDef()) + OS << "?"; + else + OS << vni->def; + if (vni->hasPHIKill()) + OS << "-phikill"; + if (vni->hasRedefByEC()) + OS << "-ec"; + } + } + } +} + +void LiveInterval::dump() const { + dbgs() << *this << "\n"; +} + + +void LiveRange::print(raw_ostream &os) const { + os << *this; +} |