//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "liveintervals"
-#include "llvm/CodeGen/LiveIntervals.h"
-#include "llvm/Function.h"
+#include "LiveIntervals.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/Target/MRegisterInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
-#include "llvm/Target/TargetRegInfo.h"
#include "llvm/Support/CFG.h"
+#include "Support/CommandLine.h"
#include "Support/Debug.h"
-#include "Support/DepthFirstIterator.h"
#include "Support/Statistic.h"
+#include "Support/STLExtras.h"
+#include "VirtRegMap.h"
#include <cmath>
#include <iostream>
#include <limits>
RegisterAnalysis<LiveIntervals> X("liveintervals",
"Live Interval Analysis");
- Statistic<> numIntervals("liveintervals", "Number of intervals");
+ Statistic<> numIntervals
+ ("liveintervals", "Number of original intervals");
+
+ Statistic<> numIntervalsAfter
+ ("liveintervals", "Number of intervals after coalescing");
+
+ Statistic<> numJoins
+ ("liveintervals", "Number of interval joins performed");
+
+ Statistic<> numPeep
+ ("liveintervals", "Number of identity moves eliminated after coalescing");
+
+ Statistic<> numFolded
+ ("liveintervals", "Number of loads/stores folded into instructions");
+
+ cl::opt<bool>
+ join("join-liveintervals",
+ cl::desc("Join compatible live intervals"),
+ cl::init(true));
};
void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const
MachineFunctionPass::getAnalysisUsage(AU);
}
+void LiveIntervals::releaseMemory()
+{
+ mbbi2mbbMap_.clear();
+ mi2iMap_.clear();
+ i2miMap_.clear();
+ r2iMap_.clear();
+ r2rMap_.clear();
+ intervals_.clear();
+}
+
+
/// runOnMachineFunction - Register allocate the whole function
///
bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
- DEBUG(std::cerr << "Machine Function\n");
mf_ = &fn;
tm_ = &fn.getTarget();
mri_ = tm_->getRegisterInfo();
lv_ = &getAnalysis<LiveVariables>();
- mbbi2mbbMap_.clear();
- mi2iMap_.clear();
- r2iMap_.clear();
- r2iMap_.clear();
- intervals_.clear();
// number MachineInstrs
unsigned miIndex = 0;
for (MachineFunction::iterator mbb = mf_->begin(), mbbEnd = mf_->end();
mbb != mbbEnd; ++mbb) {
const std::pair<MachineBasicBlock*, unsigned>& entry =
- lv_->getMachineBasicBlockInfo(&*mbb);
+ lv_->getMachineBasicBlockInfo(mbb);
bool inserted = mbbi2mbbMap_.insert(std::make_pair(entry.second,
entry.first)).second;
assert(inserted && "multiple index -> MachineBasicBlock");
for (MachineBasicBlock::iterator mi = mbb->begin(), miEnd = mbb->end();
mi != miEnd; ++mi) {
- inserted = mi2iMap_.insert(std::make_pair(*mi, miIndex)).second;
+ inserted = mi2iMap_.insert(std::make_pair(mi, miIndex)).second;
assert(inserted && "multiple MachineInstr -> index mappings");
- ++miIndex;
+ i2miMap_.push_back(mi);
+ miIndex += InstrSlots::NUM;
}
}
computeIntervals();
- // compute spill weights
+ numIntervals += intervals_.size();
+
+ // join intervals if requested
+ if (join) joinIntervals();
+
+ numIntervalsAfter += intervals_.size();
+
+ // perform a final pass over the instructions and compute spill
+ // weights, coalesce virtual registers and remove identity moves
const LoopInfo& loopInfo = getAnalysis<LoopInfo>();
const TargetInstrInfo& tii = tm_->getInstrInfo();
- for (MbbIndex2MbbMap::iterator
- it = mbbi2mbbMap_.begin(), itEnd = mbbi2mbbMap_.end();
- it != itEnd; ++it) {
- MachineBasicBlock* mbb = it->second;
-
+ for (MachineFunction::iterator mbbi = mf_->begin(), mbbe = mf_->end();
+ mbbi != mbbe; ++mbbi) {
+ MachineBasicBlock* mbb = mbbi;
unsigned loopDepth = loopInfo.getLoopDepth(mbb->getBasicBlock());
- for (MachineBasicBlock::iterator mi = mbb->begin(), miEnd = mbb->end();
- mi != miEnd; ++mi) {
- MachineInstr* instr = *mi;
- for (int i = instr->getNumOperands() - 1; i >= 0; --i) {
- MachineOperand& mop = instr->getOperand(i);
-
- if (!mop.isVirtualRegister())
- continue;
+ for (MachineBasicBlock::iterator mii = mbb->begin(), mie = mbb->end();
+ mii != mie; ) {
+ for (unsigned i = 0; i < mii->getNumOperands(); ++i) {
+ const MachineOperand& mop = mii->getOperand(i);
+ if (mop.isRegister() && mop.getReg()) {
+ // replace register with representative register
+ unsigned reg = rep(mop.getReg());
+ mii->SetMachineOperandReg(i, reg);
+
+ if (MRegisterInfo::isVirtualRegister(reg)) {
+ Reg2IntervalMap::iterator r2iit = r2iMap_.find(reg);
+ assert(r2iit != r2iMap_.end());
+ r2iit->second->weight += pow(10.0F, loopDepth);
+ }
+ }
+ }
- unsigned reg = mop.getAllocatedRegNum();
- Reg2IntervalMap::iterator r2iit = r2iMap_.find(reg);
- assert(r2iit != r2iMap_.end());
- r2iit->second->weight += pow(10.0F, loopDepth);
+ // if the move is now an identity move delete it
+ unsigned srcReg, dstReg;
+ if (tii.isMoveInstr(*mii, srcReg, dstReg) && srcReg == dstReg) {
+ // remove index -> MachineInstr and
+ // MachineInstr -> index mappings
+ Mi2IndexMap::iterator mi2i = mi2iMap_.find(mii);
+ if (mi2i != mi2iMap_.end()) {
+ i2miMap_[mi2i->second/InstrSlots::NUM] = 0;
+ mi2iMap_.erase(mi2i);
+ }
+ mii = mbbi->erase(mii);
+ ++numPeep;
}
+ else
+ ++mii;
}
}
- numIntervals += intervals_.size();
+ intervals_.sort(StartPointComp());
+ DEBUG(std::cerr << "********** INTERVALS **********\n");
+ DEBUG(std::copy(intervals_.begin(), intervals_.end(),
+ std::ostream_iterator<Interval>(std::cerr, "\n")));
+ DEBUG(std::cerr << "********** MACHINEINSTRS **********\n");
+ DEBUG(
+ for (MachineFunction::iterator mbbi = mf_->begin(), mbbe = mf_->end();
+ mbbi != mbbe; ++mbbi) {
+ std::cerr << mbbi->getBasicBlock()->getName() << ":\n";
+ for (MachineBasicBlock::iterator mii = mbbi->begin(),
+ mie = mbbi->end(); mii != mie; ++mii) {
+ std::cerr << getInstructionIndex(mii) << '\t';
+ mii->print(std::cerr, *tm_);
+ }
+ });
return true;
}
+void LiveIntervals::updateSpilledInterval(Interval& li,
+ VirtRegMap& vrm,
+ int slot)
+{
+ assert(li.weight != std::numeric_limits<float>::infinity() &&
+ "attempt to spill already spilled interval!");
+ Interval::Ranges oldRanges;
+ swap(oldRanges, li.ranges);
+
+ DEBUG(std::cerr << "\t\t\t\tupdating interval: " << li);
+
+ for (Interval::Ranges::iterator i = oldRanges.begin(), e = oldRanges.end();
+ i != e; ++i) {
+ unsigned index = getBaseIndex(i->first);
+ unsigned end = getBaseIndex(i->second-1) + InstrSlots::NUM;
+ for (; index < end; index += InstrSlots::NUM) {
+ // skip deleted instructions
+ while (!getInstructionFromIndex(index)) index += InstrSlots::NUM;
+ MachineBasicBlock::iterator mi = getInstructionFromIndex(index);
+
+ for_operand:
+ for (unsigned i = 0; i < mi->getNumOperands(); ++i) {
+ MachineOperand& mop = mi->getOperand(i);
+ if (mop.isRegister() && mop.getReg() == li.reg) {
+ if (MachineInstr* fmi =
+ mri_->foldMemoryOperand(mi, i, slot)) {
+ lv_->instructionChanged(mi, fmi);
+ vrm.virtFolded(li.reg, mi, fmi);
+ mi2iMap_.erase(mi);
+ i2miMap_[index/InstrSlots::NUM] = fmi;
+ mi2iMap_[fmi] = index;
+ MachineBasicBlock& mbb = *mi->getParent();
+ mi = mbb.insert(mbb.erase(mi), fmi);
+ ++numFolded;
+ goto for_operand;
+ }
+ else {
+ // This is tricky. We need to add information in
+ // the interval about the spill code so we have to
+ // use our extra load/store slots.
+ //
+ // If we have a use we are going to have a load so
+ // we start the interval from the load slot
+ // onwards. Otherwise we start from the def slot.
+ unsigned start = (mop.isUse() ?
+ getLoadIndex(index) :
+ getDefIndex(index));
+ // If we have a def we are going to have a store
+ // right after it so we end the interval after the
+ // use of the next instruction. Otherwise we end
+ // after the use of this instruction.
+ unsigned end = 1 + (mop.isDef() ?
+ getUseIndex(index+InstrSlots::NUM) :
+ getUseIndex(index));
+ li.addRange(start, end);
+ }
+ }
+ }
+ }
+ }
+ // the new spill weight is now infinity as it cannot be spilled again
+ li.weight = std::numeric_limits<float>::infinity();
+ DEBUG(std::cerr << '\n');
+ DEBUG(std::cerr << "\t\t\t\tupdated interval: " << li << '\n');
+}
+
void LiveIntervals::printRegName(unsigned reg) const
{
- if (reg < MRegisterInfo::FirstVirtualRegister)
+ if (MRegisterInfo::isPhysicalRegister(reg))
std::cerr << mri_->getName(reg);
else
- std::cerr << '%' << reg;
+ std::cerr << "%reg" << reg;
}
void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock* mbb,
MachineBasicBlock::iterator mi,
unsigned reg)
{
- DEBUG(std::cerr << "\t\tregister: ";printRegName(reg); std::cerr << '\n');
-
- unsigned instrIndex = getInstructionIndex(*mi);
-
+ DEBUG(std::cerr << "\t\tregister: "; printRegName(reg));
LiveVariables::VarInfo& vi = lv_->getVarInfo(reg);
Interval* interval = 0;
- Reg2IntervalMap::iterator r2iit = r2iMap_.find(reg);
- if (r2iit == r2iMap_.end()) {
+ Reg2IntervalMap::iterator r2iit = r2iMap_.lower_bound(reg);
+ if (r2iit == r2iMap_.end() || r2iit->first != reg) {
// add new interval
intervals_.push_back(Interval(reg));
// update interval index for this register
- bool inserted =
- r2iMap_.insert(std::make_pair(reg, --intervals_.end())).second;
- assert(inserted);
+ r2iMap_.insert(r2iit, std::make_pair(reg, --intervals_.end()));
interval = &intervals_.back();
+
+ // iterate over all of the blocks that the variable is
+ // completely live in, adding them to the live
+ // interval. obviously we only need to do this once.
+ for (unsigned i = 0, e = vi.AliveBlocks.size(); i != e; ++i) {
+ if (vi.AliveBlocks[i]) {
+ MachineBasicBlock* mbb = lv_->getIndexMachineBasicBlock(i);
+ if (!mbb->empty()) {
+ interval->addRange(
+ getInstructionIndex(&mbb->front()),
+ getInstructionIndex(&mbb->back()) + InstrSlots::NUM);
+ }
+ }
+ }
}
else {
interval = &*r2iit->second;
}
- for (MbbIndex2MbbMap::iterator
- it = mbbi2mbbMap_.begin(), itEnd = mbbi2mbbMap_.end();
- it != itEnd; ++it) {
- unsigned liveBlockIndex = it->first;
- MachineBasicBlock* liveBlock = it->second;
- if (liveBlockIndex < vi.AliveBlocks.size() &&
- vi.AliveBlocks[liveBlockIndex] &&
- !liveBlock->empty()) {
- unsigned start = getInstructionIndex(liveBlock->front());
- unsigned end = getInstructionIndex(liveBlock->back()) + 1;
- interval->addRange(start, end);
- }
- }
+ unsigned baseIndex = getInstructionIndex(mi);
bool killedInDefiningBasicBlock = false;
for (int i = 0, e = vi.Kills.size(); i != e; ++i) {
MachineBasicBlock* killerBlock = vi.Kills[i].first;
MachineInstr* killerInstr = vi.Kills[i].second;
unsigned start = (mbb == killerBlock ?
- instrIndex :
- getInstructionIndex(killerBlock->front()));
- unsigned end = getInstructionIndex(killerInstr) + 1;
+ getDefIndex(baseIndex) :
+ getInstructionIndex(&killerBlock->front()));
+ unsigned end = (killerInstr == mi ?
+ // dead
+ start + 1 :
+ // killed
+ getUseIndex(getInstructionIndex(killerInstr))+1);
+ // we do not want to add invalid ranges. these can happen when
+ // a variable has its latest use and is redefined later on in
+ // the same basic block (common with variables introduced by
+ // PHI elimination)
if (start < end) {
killedInDefiningBasicBlock |= mbb == killerBlock;
interval->addRange(start, end);
}
if (!killedInDefiningBasicBlock) {
- unsigned end = getInstructionIndex(mbb->back()) + 1;
- interval->addRange(instrIndex, end);
+ unsigned end = getInstructionIndex(&mbb->back()) + InstrSlots::NUM;
+ interval->addRange(getDefIndex(baseIndex), end);
}
+ DEBUG(std::cerr << '\n');
}
void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock* mbb,
unsigned reg)
{
DEBUG(std::cerr << "\t\tregister: "; printRegName(reg));
+ typedef LiveVariables::killed_iterator KillIter;
- unsigned start = getInstructionIndex(*mi);
+ MachineBasicBlock::iterator e = mbb->end();
+ unsigned baseIndex = getInstructionIndex(mi);
+ unsigned start = getDefIndex(baseIndex);
unsigned end = start;
- // register can be dead by the instruction defining it but it can
- // only be killed by subsequent instructions
-
- for (LiveVariables::killed_iterator
- ki = lv_->dead_begin(*mi),
- ke = lv_->dead_end(*mi);
+ // a variable can be dead by the instruction defining it
+ for (KillIter ki = lv_->dead_begin(mi), ke = lv_->dead_end(mi);
ki != ke; ++ki) {
if (reg == ki->second) {
- end = getInstructionIndex(ki->first) + 1;
- DEBUG(std::cerr << " dead\n");
+ DEBUG(std::cerr << " dead");
+ end = getDefIndex(start) + 1;
goto exit;
}
}
- ++mi;
- for (MachineBasicBlock::iterator e = mbb->end(); mi != e; ++mi) {
- for (LiveVariables::killed_iterator
- ki = lv_->dead_begin(*mi),
- ke = lv_->dead_end(*mi);
+ // a variable can only be killed by subsequent instructions
+ do {
+ ++mi;
+ baseIndex += InstrSlots::NUM;
+ for (KillIter ki = lv_->killed_begin(mi), ke = lv_->killed_end(mi);
ki != ke; ++ki) {
if (reg == ki->second) {
- end = getInstructionIndex(ki->first) + 1;
- DEBUG(std::cerr << " dead\n");
+ DEBUG(std::cerr << " killed");
+ end = getUseIndex(baseIndex) + 1;
goto exit;
}
}
+ } while (mi != e);
- for (LiveVariables::killed_iterator
- ki = lv_->killed_begin(*mi),
- ke = lv_->killed_end(*mi);
- ki != ke; ++ki) {
- if (reg == ki->second) {
- end = getInstructionIndex(ki->first) + 1;
- DEBUG(std::cerr << " killed\n");
- goto exit;
- }
- }
- }
exit:
assert(start < end && "did not find end of interval?");
- Reg2IntervalMap::iterator r2iit = r2iMap_.find(reg);
- if (r2iit != r2iMap_.end()) {
- Interval& interval = *r2iit->second;
- interval.addRange(start, end);
+ Reg2IntervalMap::iterator r2iit = r2iMap_.lower_bound(reg);
+ if (r2iit != r2iMap_.end() && r2iit->first == reg) {
+ r2iit->second->addRange(start, end);
}
else {
intervals_.push_back(Interval(reg));
- Interval& interval = intervals_.back();
// update interval index for this register
- bool inserted =
- r2iMap_.insert(std::make_pair(reg, --intervals_.end())).second;
- assert(inserted);
- interval.addRange(start, end);
+ r2iMap_.insert(r2iit, std::make_pair(reg, --intervals_.end()));
+ intervals_.back().addRange(start, end);
}
+ DEBUG(std::cerr << '\n');
}
void LiveIntervals::handleRegisterDef(MachineBasicBlock* mbb,
MachineBasicBlock::iterator mi,
unsigned reg)
{
- if (reg < MRegisterInfo::FirstVirtualRegister) {
+ if (MRegisterInfo::isPhysicalRegister(reg)) {
if (lv_->getAllocatablePhysicalRegisters()[reg]) {
handlePhysicalRegisterDef(mbb, mi, reg);
for (const unsigned* as = mri_->getAliasSet(reg); *as; ++as)
unsigned LiveIntervals::getInstructionIndex(MachineInstr* instr) const
{
- assert(mi2iMap_.find(instr) != mi2iMap_.end() &&
- "instruction not assigned a number");
- return mi2iMap_.find(instr)->second;
+ Mi2IndexMap::const_iterator it = mi2iMap_.find(instr);
+ return (it == mi2iMap_.end() ?
+ std::numeric_limits<unsigned>::max() :
+ it->second);
+}
+
+MachineInstr* LiveIntervals::getInstructionFromIndex(unsigned index) const
+{
+ index /= InstrSlots::NUM; // convert index to vector index
+ assert(index < i2miMap_.size() &&
+ "index does not correspond to an instruction");
+ return i2miMap_[index];
}
/// computeIntervals - computes the live intervals for virtual
/// registers. for some ordering of the machine instructions [1,N] a
-/// live interval is an interval [i, j] where 1 <= i <= j <= N for
+/// live interval is an interval [i, j) where 1 <= i <= j < N for
/// which a variable is live
void LiveIntervals::computeIntervals()
{
- DEBUG(std::cerr << "computing live intervals:\n");
+ DEBUG(std::cerr << "********** COMPUTING LIVE INTERVALS **********\n");
+ DEBUG(std::cerr << "********** Function: "
+ << mf_->getFunction()->getName() << '\n');
for (MbbIndex2MbbMap::iterator
it = mbbi2mbbMap_.begin(), itEnd = mbbi2mbbMap_.end();
it != itEnd; ++it) {
MachineBasicBlock* mbb = it->second;
- DEBUG(std::cerr << "machine basic block: "
- << mbb->getBasicBlock()->getName() << "\n");
+ DEBUG(std::cerr << mbb->getBasicBlock()->getName() << ":\n");
for (MachineBasicBlock::iterator mi = mbb->begin(), miEnd = mbb->end();
mi != miEnd; ++mi) {
- MachineInstr* instr = *mi;
const TargetInstrDescriptor& tid =
- tm_->getInstrInfo().get(instr->getOpcode());
- DEBUG(std::cerr << "\t[" << getInstructionIndex(instr) << "] ";
- instr->print(std::cerr, *tm_););
+ tm_->getInstrInfo().get(mi->getOpcode());
+ DEBUG(std::cerr << getInstructionIndex(mi) << "\t";
+ mi->print(std::cerr, *tm_));
// handle implicit defs
for (const unsigned* id = tid.ImplicitDefs; *id; ++id)
handleRegisterDef(mbb, mi, *id);
// handle explicit defs
- for (int i = instr->getNumOperands() - 1; i >= 0; --i) {
- MachineOperand& mop = instr->getOperand(i);
-
- if (!mop.isRegister())
- continue;
-
- // handle defs - build intervals
- if (mop.isDef())
- handleRegisterDef(mbb, mi, mop.getAllocatedRegNum());
+ for (int i = mi->getNumOperands() - 1; i >= 0; --i) {
+ MachineOperand& mop = mi->getOperand(i);
+ // handle register defs - build intervals
+ if (mop.isRegister() && mop.getReg() && mop.isDef())
+ handleRegisterDef(mbb, mi, mop.getReg());
}
}
}
+}
- intervals_.sort(StartPointComp());
- DEBUG(std::copy(intervals_.begin(), intervals_.end(),
- std::ostream_iterator<Interval>(std::cerr, "\n")));
+unsigned LiveIntervals::rep(unsigned reg)
+{
+ Reg2RegMap::iterator it = r2rMap_.find(reg);
+ if (it != r2rMap_.end())
+ return it->second = rep(it->second);
+ return reg;
}
-LiveIntervals::Interval::Interval(unsigned r)
- : reg(r), hint(0),
- weight((r < MRegisterInfo::FirstVirtualRegister ?
- std::numeric_limits<float>::max() : 0.0F))
+void LiveIntervals::joinIntervals()
{
+ DEBUG(std::cerr << "********** JOINING INTERVALS ***********\n");
+
+ const TargetInstrInfo& tii = tm_->getInstrInfo();
+
+ for (MachineFunction::iterator mbbi = mf_->begin(), mbbe = mf_->end();
+ mbbi != mbbe; ++mbbi) {
+ MachineBasicBlock* mbb = mbbi;
+ DEBUG(std::cerr << mbb->getBasicBlock()->getName() << ":\n");
+ for (MachineBasicBlock::iterator mi = mbb->begin(), mie = mbb->end();
+ mi != mie; ++mi) {
+ const TargetInstrDescriptor& tid =
+ tm_->getInstrInfo().get(mi->getOpcode());
+ DEBUG(std::cerr << getInstructionIndex(mi) << '\t';
+ mi->print(std::cerr, *tm_););
+
+ // we only join virtual registers with allocatable
+ // physical registers since we do not have liveness information
+ // on not allocatable physical registers
+ unsigned regA, regB;
+ if (tii.isMoveInstr(*mi, regA, regB) &&
+ (MRegisterInfo::isVirtualRegister(regA) ||
+ lv_->getAllocatablePhysicalRegisters()[regA]) &&
+ (MRegisterInfo::isVirtualRegister(regB) ||
+ lv_->getAllocatablePhysicalRegisters()[regB])) {
+
+ // get representative registers
+ regA = rep(regA);
+ regB = rep(regB);
+
+ // if they are already joined we continue
+ if (regA == regB)
+ continue;
+
+ Reg2IntervalMap::iterator r2iA = r2iMap_.find(regA);
+ assert(r2iA != r2iMap_.end());
+ Reg2IntervalMap::iterator r2iB = r2iMap_.find(regB);
+ assert(r2iB != r2iMap_.end());
+
+ Intervals::iterator intA = r2iA->second;
+ Intervals::iterator intB = r2iB->second;
+
+ // both A and B are virtual registers
+ if (MRegisterInfo::isVirtualRegister(intA->reg) &&
+ MRegisterInfo::isVirtualRegister(intB->reg)) {
+
+ const TargetRegisterClass *rcA, *rcB;
+ rcA = mf_->getSSARegMap()->getRegClass(intA->reg);
+ rcB = mf_->getSSARegMap()->getRegClass(intB->reg);
+ assert(rcA == rcB && "registers must be of the same class");
+
+ // if their intervals do not overlap we join them
+ if (!intB->overlaps(*intA)) {
+ intA->join(*intB);
+ r2iB->second = r2iA->second;
+ r2rMap_.insert(std::make_pair(intB->reg, intA->reg));
+ intervals_.erase(intB);
+ }
+ }
+ else if (MRegisterInfo::isPhysicalRegister(intA->reg) ^
+ MRegisterInfo::isPhysicalRegister(intB->reg)) {
+ if (MRegisterInfo::isPhysicalRegister(intB->reg)) {
+ std::swap(regA, regB);
+ std::swap(intA, intB);
+ std::swap(r2iA, r2iB);
+ }
+
+ assert(MRegisterInfo::isPhysicalRegister(intA->reg) &&
+ MRegisterInfo::isVirtualRegister(intB->reg) &&
+ "A must be physical and B must be virtual");
+
+ if (!intA->overlaps(*intB) &&
+ !overlapsAliases(*intA, *intB)) {
+ intA->join(*intB);
+ r2iB->second = r2iA->second;
+ r2rMap_.insert(std::make_pair(intB->reg, intA->reg));
+ intervals_.erase(intB);
+ }
+ }
+ }
+ }
+ }
}
-void LiveIntervals::Interval::addRange(unsigned start, unsigned end)
+bool LiveIntervals::overlapsAliases(const Interval& lhs,
+ const Interval& rhs) const
{
- DEBUG(std::cerr << "\t\t\tadding range: [" << start <<','<< end << ") -> ");
- //assert(start < end && "invalid range?");
- Range range = std::make_pair(start, end);
- Ranges::iterator it =
- ranges.insert(std::upper_bound(ranges.begin(), ranges.end(), range),
- range);
+ assert(MRegisterInfo::isPhysicalRegister(lhs.reg) &&
+ "first interval must describe a physical register");
+
+ for (const unsigned* as = mri_->getAliasSet(lhs.reg); *as; ++as) {
+ Reg2IntervalMap::const_iterator r2i = r2iMap_.find(*as);
+ assert(r2i != r2iMap_.end() && "alias does not have interval?");
+ if (rhs.overlaps(*r2i->second))
+ return true;
+ }
- mergeRangesForward(it);
- mergeRangesBackward(it);
- DEBUG(std::cerr << *this << '\n');
+ return false;
}
-void LiveIntervals::Interval::mergeRangesForward(Ranges::iterator it)
+LiveIntervals::Interval::Interval(unsigned r)
+ : reg(r),
+ weight((MRegisterInfo::isPhysicalRegister(r) ?
+ std::numeric_limits<float>::infinity() : 0.0F))
{
- for (Ranges::iterator next = it + 1;
- next != ranges.end() && it->second >= next->first; ) {
- it->second = std::max(it->second, next->second);
- next = ranges.erase(next);
- }
+
}
-void LiveIntervals::Interval::mergeRangesBackward(Ranges::iterator it)
+bool LiveIntervals::Interval::spilled() const
{
- for (Ranges::iterator prev = it - 1;
- it != ranges.begin() && it->first <= prev->second; ) {
- it->first = std::min(it->first, prev->first);
- it->second = std::max(it->second, prev->second);
- it = ranges.erase(prev);
- prev = it - 1;
- }
+ return (weight == std::numeric_limits<float>::infinity() &&
+ MRegisterInfo::isVirtualRegister(reg));
}
+// 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 LiveIntervals::Interval::liveAt(unsigned index) const
{
- Ranges::const_iterator r = ranges.begin();
- while (r != ranges.end() && index < r->second) {
- if (index >= r->first)
- return true;
- ++r;
- }
- return false;
+ Range dummy(index, index+1);
+ Ranges::const_iterator r = std::upper_bound(ranges.begin(),
+ ranges.end(),
+ dummy);
+ if (r == ranges.begin())
+ return false;
+
+ --r;
+ return index >= r->first && index < r->second;
}
+// 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 LiveIntervals::Interval::overlaps(const Interval& other) const
{
Ranges::const_iterator i = ranges.begin();
+ Ranges::const_iterator ie = ranges.end();
Ranges::const_iterator j = other.ranges.begin();
+ Ranges::const_iterator je = other.ranges.end();
+ if (i->first < j->first) {
+ i = std::upper_bound(i, ie, *j);
+ if (i != ranges.begin()) --i;
+ }
+ else if (j->first < i->first) {
+ j = std::upper_bound(j, je, *i);
+ if (j != other.ranges.begin()) --j;
+ }
- while (i != ranges.end() && j != other.ranges.end()) {
- if (i->first < j->first) {
- if ((i->second - 1) > j->first) {
- return true;
- }
- else {
- ++i;
- }
+ while (i != ie && j != je) {
+ if (i->first == j->first) {
+ return true;
}
- else if (j->first < i->first) {
- if ((j->second - 1) > i->first) {
+ else {
+ if (i->first > j->first) {
+ swap(i, j);
+ swap(ie, je);
+ }
+ assert(i->first < j->first);
+
+ if (i->second > j->first) {
return true;
}
else {
- ++j;
+ ++i;
}
}
- else {
- return true;
- }
}
return false;
}
+void LiveIntervals::Interval::addRange(unsigned start, unsigned end)
+{
+ assert(start < end && "Invalid range to add!");
+ DEBUG(std::cerr << " +[" << start << ',' << end << ")");
+ //assert(start < end && "invalid range?");
+ Range range = std::make_pair(start, end);
+ Ranges::iterator it =
+ ranges.insert(std::upper_bound(ranges.begin(), ranges.end(), range),
+ range);
+
+ it = mergeRangesForward(it);
+ it = mergeRangesBackward(it);
+}
+
+void LiveIntervals::Interval::join(const LiveIntervals::Interval& other)
+{
+ DEBUG(std::cerr << "\t\tjoining " << *this << " with " << other << '\n');
+ Ranges::iterator cur = ranges.begin();
+
+ for (Ranges::const_iterator i = other.ranges.begin(),
+ e = other.ranges.end(); i != e; ++i) {
+ cur = ranges.insert(std::upper_bound(cur, ranges.end(), *i), *i);
+ cur = mergeRangesForward(cur);
+ cur = mergeRangesBackward(cur);
+ }
+ weight += other.weight;
+ ++numJoins;
+}
+
+LiveIntervals::Interval::Ranges::iterator
+LiveIntervals::Interval::mergeRangesForward(Ranges::iterator it)
+{
+ Ranges::iterator n;
+ while ((n = next(it)) != ranges.end()) {
+ if (n->first > it->second)
+ break;
+ it->second = std::max(it->second, n->second);
+ n = ranges.erase(n);
+ }
+ return it;
+}
+
+LiveIntervals::Interval::Ranges::iterator
+LiveIntervals::Interval::mergeRangesBackward(Ranges::iterator it)
+{
+ while (it != ranges.begin()) {
+ Ranges::iterator p = prior(it);
+ if (it->first > p->second)
+ break;
+
+ it->first = std::min(it->first, p->first);
+ it->second = std::max(it->second, p->second);
+ it = ranges.erase(p);
+ }
+
+ return it;
+}
+
std::ostream& llvm::operator<<(std::ostream& os,
const LiveIntervals::Interval& li)
{
os << "%reg" << li.reg << ',' << li.weight << " = ";
+ if (li.empty())
+ return os << "EMPTY";
for (LiveIntervals::Interval::Ranges::const_iterator
i = li.ranges.begin(), e = li.ranges.end(); i != e; ++i) {
os << "[" << i->first << "," << i->second << ")";
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