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+//===-- 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;
+
+LiveInterval::iterator LiveInterval::find(SlotIndex Pos) {
+ // This algorithm is basically std::upper_bound.
+ // Unfortunately, std::upper_bound cannot be used with mixed types until we
+ // adopt C++0x. Many libraries can do it, but not all.
+ if (empty() || Pos >= endIndex())
+ return end();
+ iterator I = begin();
+ size_t Len = ranges.size();
+ do {
+ size_t Mid = Len >> 1;
+ if (Pos < I[Mid].end)
+ Len = Mid;
+ else
+ I += Mid + 1, Len -= Mid + 1;
+ } while (Len);
+ return 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;
+ 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);
+ }
+}
+
+/// 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);
+}
+
+/// extendInBlock - If this interval 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 *LiveInterval::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)
+ extendIntervalEndTo(I, Kill);
+ return I->valno;
+}
+
+/// 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 = find(Start);
+ assert(I != ranges.end() && "Range is not in interval!");
+ 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);
+}
+
+/// 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;
+}
+
+/// 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;
+ break;
+ }
+ }
+
+ // 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]];
+ for (iterator I = next(OutIt), E = end(); I != E; ++I) {
+ VNInfo* nextValNo = NewVNInfo[LHSValNoAssignments[I->valno->id]];
+ assert(nextValNo != 0 && "Huh?");
+
+ // 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 [0,4:0)[4,7:1) and map 0/1 onto the same value #.
+ if (OutIt->valno == nextValNo && OutIt->end == I->start) {
+ OutIt->end = I->end;
+ } else {
+ // Didn't merge. Move OutIt to the next interval,
+ ++OutIt;
+ OutIt->valno = nextValNo;
+ if (OutIt != I) {
+ OutIt->start = I->start;
+ OutIt->end = I->end;
+ }
+ }
+ }
+ // If we merge some live ranges, chop off the end.
+ ++OutIt;
+ 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) {
+ // TODO: Make this more efficient.
+ iterator InsertPos = begin();
+ for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) {
+ if (I->valno != RHSValNo)
+ continue;
+ // Map the valno in the other live range to the current live range.
+ LiveRange Tmp = *I;
+ Tmp.valno = LHSValNo;
+ InsertPos = addRangeFrom(Tmp, InsertPos);
+ }
+}
+
+
+/// 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;
+ }
+ }
+ }
+
+ // Merge the relevant flags.
+ V2->mergeFlags(V1);
+
+ // 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 {
+ OS << PrintReg(reg, TRI);
+ if (weight != 0)
+ 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 {
+ OS << vni->def;
+ if (vni->isPHIDef())
+ OS << "-phidef";
+ if (vni->hasPHIKill())
+ OS << "-phikill";
+ }
+ }
+ }
+}
+
+void LiveInterval::dump() const {
+ dbgs() << *this << "\n";
+}
+
+
+void LiveRange::print(raw_ostream &os) const {
+ os << *this;
+}
+
+unsigned ConnectedVNInfoEqClasses::Classify(const LiveInterval *LI) {
+ // Create initial equivalence classes.
+ EqClass.clear();
+ EqClass.grow(LI->getNumValNums());
+
+ const VNInfo *used = 0, *unused = 0;
+
+ // Determine connections.
+ for (LiveInterval::const_vni_iterator I = LI->vni_begin(), E = LI->vni_end();
+ I != E; ++I) {
+ const VNInfo *VNI = *I;
+ // Group all unused values into one class.
+ if (VNI->isUnused()) {
+ if (unused)
+ EqClass.join(unused->id, VNI->id);
+ unused = VNI;
+ continue;
+ }
+ used = VNI;
+ if (VNI->isPHIDef()) {
+ const MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
+ assert(MBB && "Phi-def has no defining MBB");
+ // 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)))
+ 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))
+ EqClass.join(VNI->id, UVNI->id);
+ }
+ }
+
+ // Lump all the unused values in with the last used value.
+ if (used && unused)
+ EqClass.join(used->id, unused->id);
+
+ EqClass.compress();
+ return EqClass.getNumClasses();
+}
+
+void ConnectedVNInfoEqClasses::Distribute(LiveInterval *LIV[],
+ MachineRegisterInfo &MRI) {
+ assert(LIV[0] && "LIV[0] must be set");
+ LiveInterval &LI = *LIV[0];
+
+ // 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();
+ ++RI;
+ if (MO.isUse() && MO.isUndef())
+ continue;
+ // DBG_VALUE instructions should have been eliminated earlier.
+ SlotIndex Idx = LIS.getInstructionIndex(MI);
+ Idx = Idx.getRegSlot(MO.isUse());
+ const VNInfo *VNI = LI.getVNInfoAt(Idx);
+ assert(VNI && "Interval not live at use.");
+ 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]->ranges.push_back(*I);
+ } else
+ *J++ = *I;
+ }
+ LI.ranges.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;
+ }
+ }
+ LI.valnos.resize(j);
+}
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