// Merge a LiveInterval's segments. Guarantee no overlaps.
void LiveIntervalUnion::unify(LiveInterval &VirtReg) {
if (VirtReg.empty())
return;
++Tag;
// Insert each of the virtual register's live segments into the map.
LiveInterval::iterator RegPos = VirtReg.begin();
LiveInterval::iterator RegEnd = VirtReg.end();
SegmentIter SegPos = Segments.find(RegPos->start);
while (SegPos.valid()) {
SegPos.insert(RegPos->start, RegPos->end, &VirtReg);
if (++RegPos == RegEnd)
return;
SegPos.advanceTo(RegPos->start);
}
// We have reached the end of Segments, so it is no longer necessary to search
// for the insertion position.
// It is faster to insert the end first.
--RegEnd;
SegPos.insert(RegEnd->start, RegEnd->end, &VirtReg);
for (; RegPos != RegEnd; ++RegPos, ++SegPos)
SegPos.insert(RegPos->start, RegPos->end, &VirtReg);
}
/// When adding a new instruction to liveness, the newly added definition
/// will start a new live segment. This may happen at a position that falls
/// within an existing live segment. In such case that live segment needs to
/// be truncated to make room for the new segment. Ultimately, the truncation
/// will occur at the last use, but for now the segment can be terminated
/// right at the place where the new segment will start. The segments will be
/// shrunk-to-uses later.
void HexagonExpandCondsets::terminateSegment(LiveInterval::iterator LT,
SlotIndex S, LiveInterval &LI) {
// Terminate the live segment pointed to by LT within a live interval LI.
if (LT == LI.end())
return;
VNInfo *OldVN = LT->valno;
SlotIndex EX = LT->end;
LT->end = S;
// If LT does not end at a block boundary, the termination is done.
if (!EX.isBlock())
return;
// If LT ended at a block boundary, it's possible that its value number
// is picked up at the beginning other blocks. Create a new value number
// and change such blocks to use it instead.
VNInfo *NewVN = 0;
for (LiveInterval::iterator I = LI.begin(), E = LI.end(); I != E; ++I) {
if (!I->start.isBlock() || I->valno != OldVN)
continue;
// Generate on-demand a new value number that is defined by the
// block beginning (i.e. -phi).
if (!NewVN)
NewVN = LI.getNextValue(I->start, LIS->getVNInfoAllocator());
I->valno = NewVN;
}
}
void SplitEditor::deleteRematVictims() {
SmallVector<MachineInstr*, 8> Dead;
for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I){
LiveInterval *LI = *I;
for (LiveInterval::const_iterator LII = LI->begin(), LIE = LI->end();
LII != LIE; ++LII) {
// Dead defs end at the store slot.
if (LII->end != LII->valno->def.getNextSlot())
continue;
MachineInstr *MI = LIS.getInstructionFromIndex(LII->valno->def);
assert(MI && "Missing instruction for dead def");
MI->addRegisterDead(LI->reg, &TRI);
if (!MI->allDefsAreDead())
continue;
DEBUG(dbgs() << "All defs dead: " << *MI);
Dead.push_back(MI);
}
}
if (Dead.empty())
return;
Edit->eliminateDeadDefs(Dead, LIS, VRM, TII);
}
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;
MachineInstr *MI = RI->getParent();
++RI;
// DBG_VALUE instructions don't have slot indexes, so get the index of the
// instruction before them.
// Normally, DBG_VALUE instructions are removed before this function is
// called, but it is not a requirement.
SlotIndex Idx;
if (MI->isDebugValue())
Idx = LIS.getSlotIndexes()->getIndexBefore(MI);
else
Idx = LIS.getInstructionIndex(MI);
LiveQueryResult LRQ = LI.Query(Idx);
const VNInfo *VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();
// In the case of an <undef> use that isn't tied to any def, VNI will be
// NULL. If the use is tied to a def, VNI will be the defined value.
if (!VNI)
continue;
if (unsigned EqClass = getEqClass(VNI))
MO.setReg(LIV[EqClass-1]->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-1]->empty() || LIV[eq-1]->expiredAt(I->start)) &&
"New intervals should be empty");
LIV[eq-1]->segments.push_back(*I);
} else
*J++ = *I;
}
// TODO: do not cheat anymore by simply cleaning all subranges
LI.clearSubRanges();
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-1]->getNumValNums();
LIV[eq-1]->valnos.push_back(VNI);
} else {
VNI->id = j;
LI.valnos[j++] = VNI;
}
}
LI.valnos.resize(j);
}
LiveInterval::iterator HexagonExpandCondsets::nextSegment(LiveInterval &LI,
SlotIndex S) {
for (LiveInterval::iterator I = LI.begin(), E = LI.end(); I != E; ++I) {
if (I->start >= S)
return I;
}
return LI.end();
}
/// 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) {
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);
}
LiveInterval::iterator HexagonExpandCondsets::prevSegment(LiveInterval &LI,
SlotIndex S) {
LiveInterval::iterator P = LI.end();
for (LiveInterval::iterator I = LI.begin(), E = LI.end(); I != E; ++I) {
if (I->end > S)
return P;
P = I;
}
return P;
}
static void determineMissingVNIs(const SlotIndexes &Indexes, LiveInterval &LI) {
SmallPtrSet<const MachineBasicBlock*, 5> 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());
}
bool LiveIntervals::checkRegMaskInterference(LiveInterval &LI,
BitVector &UsableRegs) {
if (LI.empty())
return false;
LiveInterval::iterator LiveI = LI.begin(), LiveE = LI.end();
// Use a smaller arrays for local live ranges.
ArrayRef<SlotIndex> Slots;
ArrayRef<const uint32_t*> Bits;
if (MachineBasicBlock *MBB = intervalIsInOneMBB(LI)) {
Slots = getRegMaskSlotsInBlock(MBB->getNumber());
Bits = getRegMaskBitsInBlock(MBB->getNumber());
} else {
Slots = getRegMaskSlots();
Bits = getRegMaskBits();
}
// We are going to enumerate all the register mask slots contained in LI.
// Start with a binary search of RegMaskSlots to find a starting point.
ArrayRef<SlotIndex>::iterator SlotI =
std::lower_bound(Slots.begin(), Slots.end(), LiveI->start);
ArrayRef<SlotIndex>::iterator SlotE = Slots.end();
// No slots in range, LI begins after the last call.
if (SlotI == SlotE)
return false;
bool Found = false;
for (;;) {
assert(*SlotI >= LiveI->start);
// Loop over all slots overlapping this segment.
while (*SlotI < LiveI->end) {
// *SlotI overlaps LI. Collect mask bits.
if (!Found) {
// This is the first overlap. Initialize UsableRegs to all ones.
UsableRegs.clear();
UsableRegs.resize(TRI->getNumRegs(), true);
Found = true;
}
// Remove usable registers clobbered by this mask.
UsableRegs.clearBitsNotInMask(Bits[SlotI-Slots.begin()]);
if (++SlotI == SlotE)
return Found;
}
// *SlotI is beyond the current LI segment.
LiveI = LI.advanceTo(LiveI, *SlotI);
if (LiveI == LiveE)
return Found;
// Advance SlotI until it overlaps.
while (*SlotI < LiveI->start)
if (++SlotI == SlotE)
return Found;
}
}
/// 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);
}
}
}
}
/// 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);
}
}
bool HexagonExpandCondsets::isIntraBlocks(LiveInterval &LI) {
for (LiveInterval::iterator I = LI.begin(), E = LI.end(); I != E; ++I) {
LiveRange::Segment &LR = *I;
// Range must start at a register...
if (!LR.start.isRegister())
return false;
// ...and end in a register or in a dead slot.
if (!LR.end.isRegister() && !LR.end.isDead())
return false;
}
return true;
}
// Merge a LiveInterval's segments. Guarantee no overlaps.
void LiveIntervalUnion::unify(LiveInterval &VirtReg) {
if (VirtReg.empty())
return;
// Insert each of the virtual register's live segments into the map.
LiveInterval::iterator RegPos = VirtReg.begin();
LiveInterval::iterator RegEnd = VirtReg.end();
SegmentIter SegPos = Segments.find(RegPos->start);
for (;;) {
SegPos.insert(RegPos->start, RegPos->end, &VirtReg);
if (++RegPos == RegEnd)
return;
SegPos.advanceTo(RegPos->start);
}
}
/// Given an updated live interval LI for register Reg, update the kill flags
/// in instructions using Reg to reflect the liveness changes.
void HexagonExpandCondsets::updateKillFlags(unsigned Reg, LiveInterval &LI) {
MRI->clearKillFlags(Reg);
for (LiveInterval::iterator I = LI.begin(), E = LI.end(); I != E; ++I) {
SlotIndex EX = I->end;
if (!EX.isRegister())
continue;
MachineInstr *MI = LIS->getInstructionFromIndex(EX);
for (auto &Op : MI->operands()) {
if (!Op.isReg() || !Op.isUse() || Op.getReg() != Reg)
continue;
// Only set the kill flag on the first encountered use of Reg in this
// instruction.
Op.setIsKill(true);
break;
}
}
}
bool LiveIntervals::computeDeadValues(LiveInterval &LI,
SmallVectorImpl<MachineInstr*> *dead) {
bool PHIRemoved = false;
for (auto VNI : LI.valnos) {
if (VNI->isUnused())
continue;
SlotIndex Def = VNI->def;
LiveRange::iterator I = LI.FindSegmentContaining(Def);
assert(I != LI.end() && "Missing segment for VNI");
// Is the register live before? Otherwise we may have to add a read-undef
// flag for subregister defs.
if (MRI->tracksSubRegLiveness()) {
if ((I == LI.begin() || std::prev(I)->end < Def) && !VNI->isPHIDef()) {
MachineInstr *MI = getInstructionFromIndex(Def);
MI->addRegisterDefReadUndef(LI.reg);
}
}
if (I->end != Def.getDeadSlot())
continue;
if (VNI->isPHIDef()) {
// This is a dead PHI. Remove it.
VNI->markUnused();
LI.removeSegment(I);
DEBUG(dbgs() << "Dead PHI at " << Def << " may separate interval\n");
PHIRemoved = true;
} else {
// This is a dead def. Make sure the instruction knows.
MachineInstr *MI = getInstructionFromIndex(Def);
assert(MI && "No instruction defining live value");
MI->addRegisterDead(LI.reg, TRI);
if (dead && MI->allDefsAreDead()) {
DEBUG(dbgs() << "All defs dead: " << Def << '\t' << *MI);
dead->push_back(MI);
}
}
}
return PHIRemoved;
}
// 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;
}
unsigned SplitAnalysis::countLiveBlocks(const LiveInterval *cli) const {
if (cli->empty())
return 0;
LiveInterval *li = const_cast<LiveInterval*>(cli);
LiveInterval::iterator LVI = li->begin();
LiveInterval::iterator LVE = li->end();
unsigned Count = 0;
// Loop over basic blocks where li is live.
MachineFunction::const_iterator MFI = LIS.getMBBFromIndex(LVI->start);
SlotIndex Stop = LIS.getMBBEndIdx(MFI);
for (;;) {
++Count;
LVI = li->advanceTo(LVI, Stop);
if (LVI == LVE)
return Count;
do {
++MFI;
Stop = LIS.getMBBEndIdx(MFI);
} while (Stop <= LVI->start);
}
}
// Remove a live virtual register's segments from this union.
void LiveIntervalUnion::extract(LiveInterval &VirtReg) {
if (VirtReg.empty())
return;
// Remove each of the virtual register's live segments from the map.
LiveInterval::iterator RegPos = VirtReg.begin();
LiveInterval::iterator RegEnd = VirtReg.end();
SegmentIter SegPos = Segments.find(RegPos->start);
for (;;) {
assert(SegPos.value() == &VirtReg && "Inconsistent LiveInterval");
SegPos.erase();
if (!SegPos.valid())
return;
// Skip all segments that may have been coalesced.
RegPos = VirtReg.advanceTo(RegPos, SegPos.start());
if (RegPos == RegEnd)
return;
SegPos.advanceTo(RegPos->start);
}
}
/// 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);
}
void LiveIntervals::addKillFlags(const VirtRegMap *VRM) {
// Keep track of regunit ranges.
SmallVector<std::pair<LiveInterval*, LiveInterval::iterator>, 8> RU;
for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
if (MRI->reg_nodbg_empty(Reg))
continue;
LiveInterval *LI = &getInterval(Reg);
if (LI->empty())
continue;
// Find the regunit intervals for the assigned register. They may overlap
// the virtual register live range, cancelling any kills.
RU.clear();
for (MCRegUnitIterator Units(VRM->getPhys(Reg), TRI); Units.isValid();
++Units) {
LiveInterval *RUInt = &getRegUnit(*Units);
if (RUInt->empty())
continue;
RU.push_back(std::make_pair(RUInt, RUInt->find(LI->begin()->end)));
}
// Every instruction that kills Reg corresponds to a live range end point.
for (LiveInterval::iterator RI = LI->begin(), RE = LI->end(); RI != RE;
++RI) {
// A block index indicates an MBB edge.
if (RI->end.isBlock())
continue;
MachineInstr *MI = getInstructionFromIndex(RI->end);
if (!MI)
continue;
// Check if any of the regunits are live beyond the end of RI. That could
// happen when a physreg is defined as a copy of a virtreg:
//
// %EAX = COPY %vreg5
// FOO %vreg5 <--- MI, cancel kill because %EAX is live.
// BAR %EAX<kill>
//
// There should be no kill flag on FOO when %vreg5 is rewritten as %EAX.
bool CancelKill = false;
for (unsigned u = 0, e = RU.size(); u != e; ++u) {
LiveInterval *RInt = RU[u].first;
LiveInterval::iterator &I = RU[u].second;
if (I == RInt->end())
continue;
I = RInt->advanceTo(I, RI->end);
if (I == RInt->end() || I->start >= RI->end)
continue;
// I is overlapping RI.
CancelKill = true;
break;
}
if (CancelKill)
MI->clearRegisterKills(Reg, NULL);
else
MI->addRegisterKilled(Reg, NULL);
}
}
}
/// 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) {
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. 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.
if (V1->id == getNumValNums()-1) {
do {
valnos.pop_back();
} while (!valnos.empty() && valnos.back()->isUnused());
} else {
V1->setIsUnused(true);
}
}
}
}
}
/// 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();
}
}
/// 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) {
verify();
// 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 && !empty()) {
// Map the first live range.
iterator OutIt = begin();
OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]];
for (iterator I = llvm::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());
}
// Rewrite Other values before changing the VNInfo ids.
// 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]];
// 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.
LiveRangeUpdater Updater(this);
for (iterator I = Other.begin(), E = Other.end(); I != E; ++I)
Updater.add(*I);
}
