X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FRegisterPressure.cpp;h=8382b0912bdec911083f373d5db9a7f500b45645;hb=9ec3763313ac986bab8414f16267605c9ab28b64;hp=c64b15ffaee5de9130ea568852900456aa3e5d3e;hpb=238bf5ada19ee411c1decff68e140966f7baf479;p=oota-llvm.git diff --git a/lib/CodeGen/RegisterPressure.cpp b/lib/CodeGen/RegisterPressure.cpp index c64b15ffaee..8382b0912bd 100644 --- a/lib/CodeGen/RegisterPressure.cpp +++ b/lib/CodeGen/RegisterPressure.cpp @@ -19,22 +19,15 @@ #include "llvm/CodeGen/RegisterClassInfo.h" #include "llvm/Support/Debug.h" #include "llvm/Support/raw_ostream.h" -#include "llvm/Target/TargetMachine.h" using namespace llvm; /// Increase pressure for each pressure set provided by TargetRegisterInfo. static void increaseSetPressure(std::vector &CurrSetPressure, - std::vector &MaxSetPressure, PSetIterator PSetI) { unsigned Weight = PSetI.getWeight(); - for (; PSetI.isValid(); ++PSetI) { + for (; PSetI.isValid(); ++PSetI) CurrSetPressure[*PSetI] += Weight; - if (&CurrSetPressure != &MaxSetPressure - && CurrSetPressure[*PSetI] > MaxSetPressure[*PSetI]) { - MaxSetPressure[*PSetI] = CurrSetPressure[*PSetI]; - } - } } /// Decrease pressure for each pressure set provided by TargetRegisterInfo. @@ -47,7 +40,7 @@ static void decreaseSetPressure(std::vector &CurrSetPressure, } } -#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) +LLVM_DUMP_METHOD void llvm::dumpRegSetPressure(ArrayRef SetPressure, const TargetRegisterInfo *TRI) { bool Empty = true; @@ -61,19 +54,21 @@ void llvm::dumpRegSetPressure(ArrayRef SetPressure, dbgs() << "\n"; } +LLVM_DUMP_METHOD void RegisterPressure::dump(const TargetRegisterInfo *TRI) const { dbgs() << "Max Pressure: "; dumpRegSetPressure(MaxSetPressure, TRI); dbgs() << "Live In: "; - for (unsigned i = 0, e = LiveInRegs.size(); i < e; ++i) - dbgs() << PrintReg(LiveInRegs[i], TRI) << " "; + for (unsigned Reg : LiveInRegs) + dbgs() << PrintVRegOrUnit(Reg, TRI) << " "; dbgs() << '\n'; dbgs() << "Live Out: "; - for (unsigned i = 0, e = LiveOutRegs.size(); i < e; ++i) - dbgs() << PrintReg(LiveOutRegs[i], TRI) << " "; + for (unsigned Reg : LiveOutRegs) + dbgs() << PrintVRegOrUnit(Reg, TRI) << " "; dbgs() << '\n'; } +LLVM_DUMP_METHOD void RegPressureTracker::dump() const { if (!isTopClosed() || !isBottomClosed()) { dbgs() << "Curr Pressure: "; @@ -81,21 +76,38 @@ void RegPressureTracker::dump() const { } P.dump(TRI); } -#endif + +void PressureDiff::dump(const TargetRegisterInfo &TRI) const { + const char *sep = ""; + for (const PressureChange &Change : *this) { + if (!Change.isValid()) + break; + dbgs() << sep << TRI.getRegPressureSetName(Change.getPSet()) + << " " << Change.getUnitInc(); + sep = " "; + } + dbgs() << '\n'; +} /// Increase the current pressure as impacted by these registers and bump /// the high water mark if needed. -void RegPressureTracker::increaseRegPressure(ArrayRef Regs) { - for (unsigned i = 0, e = Regs.size(); i != e; ++i) { - increaseSetPressure(CurrSetPressure, P.MaxSetPressure, - MRI->getPressureSets(Regs[i])); +void RegPressureTracker::increaseRegPressure(ArrayRef RegUnits) { + for (unsigned RegUnit : RegUnits) { + PSetIterator PSetI = MRI->getPressureSets(RegUnit); + unsigned Weight = PSetI.getWeight(); + for (; PSetI.isValid(); ++PSetI) { + CurrSetPressure[*PSetI] += Weight; + if (CurrSetPressure[*PSetI] > P.MaxSetPressure[*PSetI]) { + P.MaxSetPressure[*PSetI] = CurrSetPressure[*PSetI]; + } + } } } /// Simply decrease the current pressure as impacted by these registers. -void RegPressureTracker::decreaseRegPressure(ArrayRef Regs) { - for (unsigned I = 0, E = Regs.size(); I != E; ++I) - decreaseSetPressure(CurrSetPressure, MRI->getPressureSets(Regs[I])); +void RegPressureTracker::decreaseRegPressure(ArrayRef RegUnits) { + for (unsigned RegUnit : RegUnits) + decreaseSetPressure(CurrSetPressure, MRI->getPressureSets(RegUnit)); } /// Clear the result so it can be used for another round of pressure tracking. @@ -147,10 +159,39 @@ void RegionPressure::openBottom(MachineBasicBlock::const_iterator PrevBottom) { LiveInRegs.clear(); } -const LiveInterval *RegPressureTracker::getInterval(unsigned Reg) const { +void LiveRegSet::init(const MachineRegisterInfo &MRI) { + const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo(); + unsigned NumRegUnits = TRI.getNumRegs(); + unsigned NumVirtRegs = MRI.getNumVirtRegs(); + Regs.setUniverse(NumRegUnits + NumVirtRegs); + this->NumRegUnits = NumRegUnits; +} + +void LiveRegSet::clear() { + Regs.clear(); +} + +static const LiveRange *getLiveRange(const LiveIntervals &LIS, unsigned Reg) { if (TargetRegisterInfo::isVirtualRegister(Reg)) - return &LIS->getInterval(Reg); - return LIS->getCachedRegUnit(Reg); + return &LIS.getInterval(Reg); + return LIS.getCachedRegUnit(Reg); +} + +void RegPressureTracker::reset() { + MBB = nullptr; + LIS = nullptr; + + CurrSetPressure.clear(); + LiveThruPressure.clear(); + P.MaxSetPressure.clear(); + + if (RequireIntervals) + static_cast(P).reset(); + else + static_cast(P).reset(); + + LiveRegs.clear(); + UntiedDefs.clear(); } /// Setup the RegPressureTracker. @@ -163,8 +204,10 @@ void RegPressureTracker::init(const MachineFunction *mf, MachineBasicBlock::const_iterator pos, bool ShouldTrackUntiedDefs) { + reset(); + MF = mf; - TRI = MF->getTarget().getRegisterInfo(); + TRI = MF->getSubtarget().getRegisterInfo(); RCI = rci; MRI = &MF->getRegInfo(); MBB = mbb; @@ -177,19 +220,10 @@ void RegPressureTracker::init(const MachineFunction *mf, CurrPos = pos; CurrSetPressure.assign(TRI->getNumRegPressureSets(), 0); - LiveThruPressure.clear(); - if (RequireIntervals) - static_cast(P).reset(); - else - static_cast(P).reset(); P.MaxSetPressure = CurrSetPressure; - LiveRegs.PhysRegs.clear(); - LiveRegs.PhysRegs.setUniverse(TRI->getNumRegs()); - LiveRegs.VirtRegs.clear(); - LiveRegs.VirtRegs.setUniverse(MRI->getNumVirtRegs()); - UntiedDefs.clear(); + LiveRegs.init(*MRI); if (TrackUntiedDefs) UntiedDefs.setUniverse(MRI->getNumVirtRegs()); } @@ -228,14 +262,8 @@ void RegPressureTracker::closeTop() { static_cast(P).TopPos = CurrPos; assert(P.LiveInRegs.empty() && "inconsistent max pressure result"); - P.LiveInRegs.reserve(LiveRegs.PhysRegs.size() + LiveRegs.VirtRegs.size()); - P.LiveInRegs.append(LiveRegs.PhysRegs.begin(), LiveRegs.PhysRegs.end()); - for (SparseSet::const_iterator I = - LiveRegs.VirtRegs.begin(), E = LiveRegs.VirtRegs.end(); I != E; ++I) - P.LiveInRegs.push_back(*I); - std::sort(P.LiveInRegs.begin(), P.LiveInRegs.end()); - P.LiveInRegs.erase(std::unique(P.LiveInRegs.begin(), P.LiveInRegs.end()), - P.LiveInRegs.end()); + P.LiveInRegs.reserve(LiveRegs.size()); + LiveRegs.appendTo(P.LiveInRegs); } /// Set the boundary for the bottom of the region and summarize live outs. @@ -246,21 +274,14 @@ void RegPressureTracker::closeBottom() { static_cast(P).BottomPos = CurrPos; assert(P.LiveOutRegs.empty() && "inconsistent max pressure result"); - P.LiveOutRegs.reserve(LiveRegs.PhysRegs.size() + LiveRegs.VirtRegs.size()); - P.LiveOutRegs.append(LiveRegs.PhysRegs.begin(), LiveRegs.PhysRegs.end()); - for (SparseSet::const_iterator I = - LiveRegs.VirtRegs.begin(), E = LiveRegs.VirtRegs.end(); I != E; ++I) - P.LiveOutRegs.push_back(*I); - std::sort(P.LiveOutRegs.begin(), P.LiveOutRegs.end()); - P.LiveOutRegs.erase(std::unique(P.LiveOutRegs.begin(), P.LiveOutRegs.end()), - P.LiveOutRegs.end()); + P.LiveOutRegs.reserve(LiveRegs.size()); + LiveRegs.appendTo(P.LiveOutRegs); } /// Finalize the region boundaries and record live ins and live outs. void RegPressureTracker::closeRegion() { if (!isTopClosed() && !isBottomClosed()) { - assert(LiveRegs.PhysRegs.empty() && LiveRegs.VirtRegs.empty() && - "no region boundary"); + assert(LiveRegs.size() == 0 && "no region boundary"); return; } if (!isBottomClosed()) @@ -277,84 +298,193 @@ void RegPressureTracker::closeRegion() { void RegPressureTracker::initLiveThru(const RegPressureTracker &RPTracker) { LiveThruPressure.assign(TRI->getNumRegPressureSets(), 0); assert(isBottomClosed() && "need bottom-up tracking to intialize."); - for (unsigned i = 0, e = P.LiveOutRegs.size(); i < e; ++i) { - unsigned Reg = P.LiveOutRegs[i]; + for (unsigned Reg : P.LiveOutRegs) { if (TargetRegisterInfo::isVirtualRegister(Reg) && !RPTracker.hasUntiedDef(Reg)) { - increaseSetPressure(LiveThruPressure, LiveThruPressure, - MRI->getPressureSets(Reg)); + increaseSetPressure(LiveThruPressure, MRI->getPressureSets(Reg)); } } } /// \brief Convenient wrapper for checking membership in RegisterOperands. -static bool containsReg(ArrayRef Regs, unsigned Reg) { - return std::find(Regs.begin(), Regs.end(), Reg) != Regs.end(); +/// (std::count() doesn't have an early exit). +static bool containsReg(ArrayRef RegUnits, unsigned RegUnit) { + return std::find(RegUnits.begin(), RegUnits.end(), RegUnit) != RegUnits.end(); } -/// Collect this instruction's unique uses and defs into SmallVectors for -/// processing defs and uses in order. -class RegisterOperands { - const TargetRegisterInfo *TRI; - const MachineRegisterInfo *MRI; +namespace { +/// List of register defined and used by a machine instruction. +class RegisterOperands { public: SmallVector Uses; SmallVector Defs; SmallVector DeadDefs; - RegisterOperands(const TargetRegisterInfo *tri, - const MachineRegisterInfo *mri): TRI(tri), MRI(mri) {} + void collect(const MachineInstr &MI, const TargetRegisterInfo &TRI, + const MachineRegisterInfo &MRI, bool IgnoreDead = false); + + /// Use liveness information to find dead defs not marked with a dead flag + /// and move them to the DeadDefs vector. + void detectDeadDefs(const MachineInstr &MI, const LiveIntervals &LIS); +}; - /// Push this operand's register onto the correct vector. - void collect(const MachineOperand &MO) { +/// Collect this instruction's unique uses and defs into SmallVectors for +/// processing defs and uses in order. +/// +/// FIXME: always ignore tied opers +class RegisterOperandsCollector { + RegisterOperands &RegOpers; + const TargetRegisterInfo &TRI; + const MachineRegisterInfo &MRI; + bool IgnoreDead; + + RegisterOperandsCollector(RegisterOperands &RegOpers, + const TargetRegisterInfo &TRI, + const MachineRegisterInfo &MRI, + bool IgnoreDead) + : RegOpers(RegOpers), TRI(TRI), MRI(MRI), IgnoreDead(IgnoreDead) {} + + void collectInstr(const MachineInstr &MI) const { + for (ConstMIBundleOperands OperI(&MI); OperI.isValid(); ++OperI) + collectOperand(*OperI); + + // Remove redundant physreg dead defs. + SmallVectorImpl::iterator I = + std::remove_if(RegOpers.DeadDefs.begin(), RegOpers.DeadDefs.end(), + std::bind1st(std::ptr_fun(containsReg), RegOpers.Defs)); + RegOpers.DeadDefs.erase(I, RegOpers.DeadDefs.end()); + } + + /// Push this operand's register onto the correct vectors. + void collectOperand(const MachineOperand &MO) const { if (!MO.isReg() || !MO.getReg()) return; + unsigned Reg = MO.getReg(); if (MO.readsReg()) - pushRegUnits(MO.getReg(), Uses); + pushRegUnits(Reg, RegOpers.Uses); if (MO.isDef()) { - if (MO.isDead()) - pushRegUnits(MO.getReg(), DeadDefs); - else - pushRegUnits(MO.getReg(), Defs); + if (MO.isDead()) { + if (!IgnoreDead) + pushRegUnits(Reg, RegOpers.DeadDefs); + } else + pushRegUnits(Reg, RegOpers.Defs); } } -protected: - void pushRegUnits(unsigned Reg, SmallVectorImpl &Regs) { + void pushRegUnits(unsigned Reg, SmallVectorImpl &RegUnits) const { if (TargetRegisterInfo::isVirtualRegister(Reg)) { - if (containsReg(Regs, Reg)) + if (containsReg(RegUnits, Reg)) return; - Regs.push_back(Reg); - } - else if (MRI->isAllocatable(Reg)) { - for (MCRegUnitIterator Units(Reg, TRI); Units.isValid(); ++Units) { - if (containsReg(Regs, *Units)) + RegUnits.push_back(Reg); + } else if (MRI.isAllocatable(Reg)) { + for (MCRegUnitIterator Units(Reg, &TRI); Units.isValid(); ++Units) { + if (containsReg(RegUnits, *Units)) continue; - Regs.push_back(*Units); + RegUnits.push_back(*Units); } } } + + friend class RegisterOperands; }; -/// Collect physical and virtual register operands. -static void collectOperands(const MachineInstr *MI, - RegisterOperands &RegOpers) { - for (ConstMIBundleOperands OperI(MI); OperI.isValid(); ++OperI) - RegOpers.collect(*OperI); +void RegisterOperands::collect(const MachineInstr &MI, + const TargetRegisterInfo &TRI, + const MachineRegisterInfo &MRI, + bool IgnoreDead) { + RegisterOperandsCollector Collector(*this, TRI, MRI, IgnoreDead); + Collector.collectInstr(MI); +} + +void RegisterOperands::detectDeadDefs(const MachineInstr &MI, + const LiveIntervals &LIS) { + SlotIndex SlotIdx = LIS.getInstructionIndex(&MI); + for (SmallVectorImpl::iterator RI = Defs.begin(); + RI != Defs.end(); /*empty*/) { + unsigned Reg = *RI; + const LiveRange *LR = getLiveRange(LIS, Reg); + if (LR != nullptr) { + LiveQueryResult LRQ = LR->Query(SlotIdx); + if (LRQ.isDeadDef()) { + // LiveIntervals knows this is a dead even though it's MachineOperand is + // not flagged as such. + DeadDefs.push_back(Reg); + RI = Defs.erase(RI); + continue; + } + } + ++RI; + } +} - // Remove redundant physreg dead defs. - SmallVectorImpl::iterator I = - std::remove_if(RegOpers.DeadDefs.begin(), RegOpers.DeadDefs.end(), - std::bind1st(std::ptr_fun(containsReg), RegOpers.Defs)); - RegOpers.DeadDefs.erase(I, RegOpers.DeadDefs.end()); +} // namespace + +/// Initialize an array of N PressureDiffs. +void PressureDiffs::init(unsigned N) { + Size = N; + if (N <= Max) { + memset(PDiffArray, 0, N * sizeof(PressureDiff)); + return; + } + Max = Size; + free(PDiffArray); + PDiffArray = reinterpret_cast(calloc(N, sizeof(PressureDiff))); +} + +/// Add a change in pressure to the pressure diff of a given instruction. +void PressureDiff::addPressureChange(unsigned RegUnit, bool IsDec, + const MachineRegisterInfo *MRI) { + PSetIterator PSetI = MRI->getPressureSets(RegUnit); + int Weight = IsDec ? -PSetI.getWeight() : PSetI.getWeight(); + for (; PSetI.isValid(); ++PSetI) { + // Find an existing entry in the pressure diff for this PSet. + PressureDiff::iterator I = nonconst_begin(), E = nonconst_end(); + for (; I != E && I->isValid(); ++I) { + if (I->getPSet() >= *PSetI) + break; + } + // If all pressure sets are more constrained, skip the remaining PSets. + if (I == E) + break; + // Insert this PressureChange. + if (!I->isValid() || I->getPSet() != *PSetI) { + PressureChange PTmp = PressureChange(*PSetI); + for (PressureDiff::iterator J = I; J != E && PTmp.isValid(); ++J) + std::swap(*J, PTmp); + } + // Update the units for this pressure set. + unsigned NewUnitInc = I->getUnitInc() + Weight; + if (NewUnitInc != 0) { + I->setUnitInc(NewUnitInc); + } else { + // Remove entry + PressureDiff::iterator J; + for (J = std::next(I); J != E && J->isValid(); ++J, ++I) + *I = *J; + if (J != E) + *I = *J; + } + } +} + +/// Record the pressure difference induced by the given operand list. +static void collectPDiff(PressureDiff &PDiff, RegisterOperands &RegOpers, + const MachineRegisterInfo *MRI) { + assert(!PDiff.begin()->isValid() && "stale PDiff"); + + for (unsigned Reg : RegOpers.Defs) + PDiff.addPressureChange(Reg, true, MRI); + + for (unsigned Reg : RegOpers.Uses) + PDiff.addPressureChange(Reg, false, MRI); } /// Force liveness of registers. void RegPressureTracker::addLiveRegs(ArrayRef Regs) { - for (unsigned i = 0, e = Regs.size(); i != e; ++i) { - if (LiveRegs.insert(Regs[i])) - increaseRegPressure(Regs[i]); + for (unsigned Reg : Regs) { + if (LiveRegs.insert(Reg)) + increaseRegPressure(Reg); } } @@ -366,8 +496,7 @@ void RegPressureTracker::discoverLiveIn(unsigned Reg) { // At live in discovery, unconditionally increase the high water mark. P.LiveInRegs.push_back(Reg); - increaseSetPressure(P.MaxSetPressure, P.MaxSetPressure, - MRI->getPressureSets(Reg)); + increaseSetPressure(P.MaxSetPressure, MRI->getPressureSets(Reg)); } /// Add Reg to the live out set and increase max pressure. @@ -378,17 +507,17 @@ void RegPressureTracker::discoverLiveOut(unsigned Reg) { // At live out discovery, unconditionally increase the high water mark. P.LiveOutRegs.push_back(Reg); - increaseSetPressure(P.MaxSetPressure, P.MaxSetPressure, - MRI->getPressureSets(Reg)); + increaseSetPressure(P.MaxSetPressure, MRI->getPressureSets(Reg)); } -/// Recede across the previous instruction. -bool RegPressureTracker::recede() { - // Check for the top of the analyzable region. - if (CurrPos == MBB->begin()) { - closeRegion(); - return false; - } +/// Recede across the previous instruction. If LiveUses is provided, record any +/// RegUnits that are made live by the current instruction's uses. This includes +/// registers that are both defined and used by the instruction. If a pressure +/// difference pointer is provided record the changes is pressure caused by this +/// instruction independent of liveness. +void RegPressureTracker::recede(SmallVectorImpl *LiveUses, + PressureDiff *PDiff) { + assert(CurrPos != MBB->begin()); if (!isBottomClosed()) closeBottom(); @@ -400,11 +529,8 @@ bool RegPressureTracker::recede() { do --CurrPos; while (CurrPos != MBB->begin() && CurrPos->isDebugValue()); + assert(!CurrPos->isDebugValue()); - if (CurrPos->isDebugValue()) { - closeRegion(); - return false; - } SlotIndex SlotIdx; if (RequireIntervals) SlotIdx = LIS->getInstructionIndex(CurrPos).getRegSlot(); @@ -413,8 +539,14 @@ bool RegPressureTracker::recede() { if (RequireIntervals && isTopClosed()) static_cast(P).openTop(SlotIdx); - RegisterOperands RegOpers(TRI, MRI); - collectOperands(CurrPos, RegOpers); + const MachineInstr &MI = *CurrPos; + RegisterOperands RegOpers; + RegOpers.collect(MI, *TRI, *MRI); + if (RequireIntervals) + RegOpers.detectDeadDefs(MI, *LIS); + + if (PDiff) + collectPDiff(*PDiff, RegOpers, MRI); // Boost pressure for all dead defs together. increaseRegPressure(RegOpers.DeadDefs); @@ -422,8 +554,7 @@ bool RegPressureTracker::recede() { // Kill liveness at live defs. // TODO: consider earlyclobbers? - for (unsigned i = 0, e = RegOpers.Defs.size(); i < e; ++i) { - unsigned Reg = RegOpers.Defs[i]; + for (unsigned Reg : RegOpers.Defs) { if (LiveRegs.erase(Reg)) decreaseRegPressure(Reg); else @@ -431,38 +562,36 @@ bool RegPressureTracker::recede() { } // Generate liveness for uses. - for (unsigned i = 0, e = RegOpers.Uses.size(); i < e; ++i) { - unsigned Reg = RegOpers.Uses[i]; + for (unsigned Reg : RegOpers.Uses) { if (!LiveRegs.contains(Reg)) { // Adjust liveouts if LiveIntervals are available. if (RequireIntervals) { - const LiveInterval *LI = getInterval(Reg); - if (LI && !LI->killedAt(SlotIdx)) - discoverLiveOut(Reg); + const LiveRange *LR = getLiveRange(*LIS, Reg); + if (LR) { + LiveQueryResult LRQ = LR->Query(SlotIdx); + if (!LRQ.isKill() && !LRQ.valueDefined()) + discoverLiveOut(Reg); + } } increaseRegPressure(Reg); LiveRegs.insert(Reg); + if (LiveUses && !containsReg(*LiveUses, Reg)) + LiveUses->push_back(Reg); } } if (TrackUntiedDefs) { - for (unsigned i = 0, e = RegOpers.Defs.size(); i < e; ++i) { - unsigned Reg = RegOpers.Defs[i]; + for (unsigned Reg : RegOpers.Defs) { if (TargetRegisterInfo::isVirtualRegister(Reg) && !LiveRegs.contains(Reg)) UntiedDefs.insert(Reg); } } - return true; } /// Advance across the current instruction. -bool RegPressureTracker::advance() { +void RegPressureTracker::advance() { assert(!TrackUntiedDefs && "unsupported mode"); - // Check for the bottom of the analyzable region. - if (CurrPos == MBB->end()) { - closeRegion(); - return false; - } + assert(CurrPos != MBB->end()); if (!isTopClosed()) closeTop(); @@ -478,11 +607,10 @@ bool RegPressureTracker::advance() { static_cast(P).openBottom(CurrPos); } - RegisterOperands RegOpers(TRI, MRI); - collectOperands(CurrPos, RegOpers); + RegisterOperands RegOpers; + RegOpers.collect(*CurrPos, *TRI, *MRI); - for (unsigned i = 0, e = RegOpers.Uses.size(); i < e; ++i) { - unsigned Reg = RegOpers.Uses[i]; + for (unsigned Reg : RegOpers.Uses) { // Discover live-ins. bool isLive = LiveRegs.contains(Reg); if (!isLive) @@ -490,24 +618,21 @@ bool RegPressureTracker::advance() { // Kill liveness at last uses. bool lastUse = false; if (RequireIntervals) { - const LiveInterval *LI = getInterval(Reg); - lastUse = LI && LI->killedAt(SlotIdx); - } - else { + const LiveRange *LR = getLiveRange(*LIS, Reg); + lastUse = LR && LR->Query(SlotIdx).isKill(); + } else { // Allocatable physregs are always single-use before register rewriting. lastUse = !TargetRegisterInfo::isVirtualRegister(Reg); } if (lastUse && isLive) { LiveRegs.erase(Reg); decreaseRegPressure(Reg); - } - else if (!lastUse && !isLive) + } else if (!lastUse && !isLive) increaseRegPressure(Reg); } // Generate liveness for defs. - for (unsigned i = 0, e = RegOpers.Defs.size(); i < e; ++i) { - unsigned Reg = RegOpers.Defs[i]; + for (unsigned Reg : RegOpers.Defs) { if (LiveRegs.insert(Reg)) increaseRegPressure(Reg); } @@ -520,7 +645,6 @@ bool RegPressureTracker::advance() { do ++CurrPos; while (CurrPos != MBB->end() && CurrPos->isDebugValue()); - return true; } /// Find the max change in excess pressure across all sets. @@ -529,8 +653,7 @@ static void computeExcessPressureDelta(ArrayRef OldPressureVec, RegPressureDelta &Delta, const RegisterClassInfo *RCI, ArrayRef LiveThruPressureVec) { - int ExcessUnits = 0; - unsigned PSetID = ~0U; + Delta.Excess = PressureChange(); for (unsigned i = 0, e = OldPressureVec.size(); i < e; ++i) { unsigned POld = OldPressureVec[i]; unsigned PNew = NewPressureVec[i]; @@ -547,18 +670,15 @@ static void computeExcessPressureDelta(ArrayRef OldPressureVec, PDiff = 0; // Under the limit else PDiff = PNew - Limit; // Just exceeded limit. - } - else if (Limit > PNew) + } else if (Limit > PNew) PDiff = Limit - POld; // Just obeyed limit. if (PDiff) { - ExcessUnits = PDiff; - PSetID = i; + Delta.Excess = PressureChange(i); + Delta.Excess.setUnitInc(PDiff); break; } } - Delta.Excess.PSetID = PSetID; - Delta.Excess.UnitIncrease = ExcessUnits; } /// Find the max change in max pressure that either surpasses a critical PSet @@ -569,11 +689,11 @@ static void computeExcessPressureDelta(ArrayRef OldPressureVec, /// RegPressureTracker API change to work with pressure differences. static void computeMaxPressureDelta(ArrayRef OldMaxPressureVec, ArrayRef NewMaxPressureVec, - ArrayRef CriticalPSets, + ArrayRef CriticalPSets, ArrayRef MaxPressureLimit, RegPressureDelta &Delta) { - Delta.CriticalMax = PressureElement(); - Delta.CurrentMax = PressureElement(); + Delta.CriticalMax = PressureChange(); + Delta.CurrentMax = PressureChange(); unsigned CritIdx = 0, CritEnd = CriticalPSets.size(); for (unsigned i = 0, e = OldMaxPressureVec.size(); i < e; ++i) { @@ -583,27 +703,24 @@ static void computeMaxPressureDelta(ArrayRef OldMaxPressureVec, continue; if (!Delta.CriticalMax.isValid()) { - while (CritIdx != CritEnd && CriticalPSets[CritIdx].PSetID < i) + while (CritIdx != CritEnd && CriticalPSets[CritIdx].getPSet() < i) ++CritIdx; - if (CritIdx != CritEnd && CriticalPSets[CritIdx].PSetID == i) { - int PDiff = (int)PNew - (int)CriticalPSets[CritIdx].UnitIncrease; + if (CritIdx != CritEnd && CriticalPSets[CritIdx].getPSet() == i) { + int PDiff = (int)PNew - (int)CriticalPSets[CritIdx].getUnitInc(); if (PDiff > 0) { - Delta.CriticalMax.PSetID = i; - Delta.CriticalMax.UnitIncrease = PDiff; + Delta.CriticalMax = PressureChange(i); + Delta.CriticalMax.setUnitInc(PDiff); } } } // Find the first increase above MaxPressureLimit. // (Ignores negative MDiff). - if (!Delta.CurrentMax.isValid()) { - int MDiff = (int)PNew - (int)MaxPressureLimit[i]; - if (MDiff > 0) { - Delta.CurrentMax.PSetID = i; - Delta.CurrentMax.UnitIncrease = MDiff; - if (CritIdx == CritEnd || Delta.CriticalMax.isValid()) - break; - } + if (!Delta.CurrentMax.isValid() && PNew > MaxPressureLimit[i]) { + Delta.CurrentMax = PressureChange(i); + Delta.CurrentMax.setUnitInc(PNew - POld); + if (CritIdx == CritEnd || Delta.CriticalMax.isValid()) + break; } } } @@ -618,23 +735,19 @@ void RegPressureTracker::bumpUpwardPressure(const MachineInstr *MI) { assert(!MI->isDebugValue() && "Expect a nondebug instruction."); // Account for register pressure similar to RegPressureTracker::recede(). - RegisterOperands RegOpers(TRI, MRI); - collectOperands(MI, RegOpers); - - // Boost max pressure for all dead defs together. - // Since CurrSetPressure and MaxSetPressure - increaseRegPressure(RegOpers.DeadDefs); - decreaseRegPressure(RegOpers.DeadDefs); + RegisterOperands RegOpers; + RegOpers.collect(*MI, *TRI, *MRI, /*IgnoreDead=*/true); + assert(RegOpers.DeadDefs.size() == 0); + if (RequireIntervals) + RegOpers.detectDeadDefs(*MI, *LIS); // Kill liveness at live defs. - for (unsigned i = 0, e = RegOpers.Defs.size(); i < e; ++i) { - unsigned Reg = RegOpers.Defs[i]; + for (unsigned Reg : RegOpers.Defs) { if (!containsReg(RegOpers.Uses, Reg)) decreaseRegPressure(Reg); } // Generate liveness for uses. - for (unsigned i = 0, e = RegOpers.Uses.size(); i < e; ++i) { - unsigned Reg = RegOpers.Uses[i]; + for (unsigned Reg : RegOpers.Uses) { if (!LiveRegs.contains(Reg)) increaseRegPressure(Reg); } @@ -648,12 +761,15 @@ void RegPressureTracker::bumpUpwardPressure(const MachineInstr *MI) { /// /// This assumes that the current LiveOut set is sufficient. /// -/// FIXME: This is expensive for an on-the-fly query. We need to cache the -/// result per-SUnit with enough information to adjust for the current -/// scheduling position. But this works as a proof of concept. +/// This is expensive for an on-the-fly query because it calls +/// bumpUpwardPressure to recompute the pressure sets based on current +/// liveness. This mainly exists to verify correctness, e.g. with +/// -verify-misched. getUpwardPressureDelta is the fast version of this query +/// that uses the per-SUnit cache of the PressureDiff. void RegPressureTracker:: -getMaxUpwardPressureDelta(const MachineInstr *MI, RegPressureDelta &Delta, - ArrayRef CriticalPSets, +getMaxUpwardPressureDelta(const MachineInstr *MI, PressureDiff *PDiff, + RegPressureDelta &Delta, + ArrayRef CriticalPSets, ArrayRef MaxPressureLimit) { // Snapshot Pressure. // FIXME: The snapshot heap space should persist. But I'm planning to @@ -667,28 +783,124 @@ getMaxUpwardPressureDelta(const MachineInstr *MI, RegPressureDelta &Delta, LiveThruPressure); computeMaxPressureDelta(SavedMaxPressure, P.MaxSetPressure, CriticalPSets, MaxPressureLimit, Delta); - assert(Delta.CriticalMax.UnitIncrease >= 0 && - Delta.CurrentMax.UnitIncrease >= 0 && "cannot decrease max pressure"); + assert(Delta.CriticalMax.getUnitInc() >= 0 && + Delta.CurrentMax.getUnitInc() >= 0 && "cannot decrease max pressure"); // Restore the tracker's state. P.MaxSetPressure.swap(SavedMaxPressure); CurrSetPressure.swap(SavedPressure); + +#ifndef NDEBUG + if (!PDiff) + return; + + // Check if the alternate algorithm yields the same result. + RegPressureDelta Delta2; + getUpwardPressureDelta(MI, *PDiff, Delta2, CriticalPSets, MaxPressureLimit); + if (Delta != Delta2) { + dbgs() << "PDiff: "; + PDiff->dump(*TRI); + dbgs() << "DELTA: " << *MI; + if (Delta.Excess.isValid()) + dbgs() << "Excess1 " << TRI->getRegPressureSetName(Delta.Excess.getPSet()) + << " " << Delta.Excess.getUnitInc() << "\n"; + if (Delta.CriticalMax.isValid()) + dbgs() << "Critic1 " << TRI->getRegPressureSetName(Delta.CriticalMax.getPSet()) + << " " << Delta.CriticalMax.getUnitInc() << "\n"; + if (Delta.CurrentMax.isValid()) + dbgs() << "CurrMx1 " << TRI->getRegPressureSetName(Delta.CurrentMax.getPSet()) + << " " << Delta.CurrentMax.getUnitInc() << "\n"; + if (Delta2.Excess.isValid()) + dbgs() << "Excess2 " << TRI->getRegPressureSetName(Delta2.Excess.getPSet()) + << " " << Delta2.Excess.getUnitInc() << "\n"; + if (Delta2.CriticalMax.isValid()) + dbgs() << "Critic2 " << TRI->getRegPressureSetName(Delta2.CriticalMax.getPSet()) + << " " << Delta2.CriticalMax.getUnitInc() << "\n"; + if (Delta2.CurrentMax.isValid()) + dbgs() << "CurrMx2 " << TRI->getRegPressureSetName(Delta2.CurrentMax.getPSet()) + << " " << Delta2.CurrentMax.getUnitInc() << "\n"; + llvm_unreachable("RegP Delta Mismatch"); + } +#endif +} + +/// This is the fast version of querying register pressure that does not +/// directly depend on current liveness. +/// +/// @param Delta captures information needed for heuristics. +/// +/// @param CriticalPSets Are the pressure sets that are known to exceed some +/// limit within the region, not necessarily at the current position. +/// +/// @param MaxPressureLimit Is the max pressure within the region, not +/// necessarily at the current position. +void RegPressureTracker:: +getUpwardPressureDelta(const MachineInstr *MI, /*const*/ PressureDiff &PDiff, + RegPressureDelta &Delta, + ArrayRef CriticalPSets, + ArrayRef MaxPressureLimit) const { + unsigned CritIdx = 0, CritEnd = CriticalPSets.size(); + for (PressureDiff::const_iterator + PDiffI = PDiff.begin(), PDiffE = PDiff.end(); + PDiffI != PDiffE && PDiffI->isValid(); ++PDiffI) { + + unsigned PSetID = PDiffI->getPSet(); + unsigned Limit = RCI->getRegPressureSetLimit(PSetID); + if (!LiveThruPressure.empty()) + Limit += LiveThruPressure[PSetID]; + + unsigned POld = CurrSetPressure[PSetID]; + unsigned MOld = P.MaxSetPressure[PSetID]; + unsigned MNew = MOld; + // Ignore DeadDefs here because they aren't captured by PressureChange. + unsigned PNew = POld + PDiffI->getUnitInc(); + assert((PDiffI->getUnitInc() >= 0) == (PNew >= POld) + && "PSet overflow/underflow"); + if (PNew > MOld) + MNew = PNew; + // Check if current pressure has exceeded the limit. + if (!Delta.Excess.isValid()) { + unsigned ExcessInc = 0; + if (PNew > Limit) + ExcessInc = POld > Limit ? PNew - POld : PNew - Limit; + else if (POld > Limit) + ExcessInc = Limit - POld; + if (ExcessInc) { + Delta.Excess = PressureChange(PSetID); + Delta.Excess.setUnitInc(ExcessInc); + } + } + // Check if max pressure has exceeded a critical pressure set max. + if (MNew == MOld) + continue; + if (!Delta.CriticalMax.isValid()) { + while (CritIdx != CritEnd && CriticalPSets[CritIdx].getPSet() < PSetID) + ++CritIdx; + + if (CritIdx != CritEnd && CriticalPSets[CritIdx].getPSet() == PSetID) { + int CritInc = (int)MNew - (int)CriticalPSets[CritIdx].getUnitInc(); + if (CritInc > 0 && CritInc <= INT16_MAX) { + Delta.CriticalMax = PressureChange(PSetID); + Delta.CriticalMax.setUnitInc(CritInc); + } + } + } + // Check if max pressure has exceeded the current max. + if (!Delta.CurrentMax.isValid() && MNew > MaxPressureLimit[PSetID]) { + Delta.CurrentMax = PressureChange(PSetID); + Delta.CurrentMax.setUnitInc(MNew - MOld); + } + } } /// Helper to find a vreg use between two indices [PriorUseIdx, NextUseIdx). -static bool findUseBetween(unsigned Reg, - SlotIndex PriorUseIdx, SlotIndex NextUseIdx, - const MachineRegisterInfo *MRI, +static bool findUseBetween(unsigned Reg, SlotIndex PriorUseIdx, + SlotIndex NextUseIdx, const MachineRegisterInfo &MRI, const LiveIntervals *LIS) { - for (MachineRegisterInfo::use_nodbg_iterator - UI = MRI->use_nodbg_begin(Reg), UE = MRI->use_nodbg_end(); - UI != UE; UI.skipInstruction()) { - const MachineInstr* MI = &*UI; - if (MI->isDebugValue()) - continue; - SlotIndex InstSlot = LIS->getInstructionIndex(MI).getRegSlot(); - if (InstSlot >= PriorUseIdx && InstSlot < NextUseIdx) - return true; + for (const MachineInstr &MI : MRI.use_nodbg_instructions(Reg)) { + SlotIndex InstSlot = LIS->getInstructionIndex(&MI).getRegSlot(); + if (InstSlot >= PriorUseIdx && InstSlot < NextUseIdx) + return true; } return false; } @@ -703,8 +915,8 @@ void RegPressureTracker::bumpDownwardPressure(const MachineInstr *MI) { assert(!MI->isDebugValue() && "Expect a nondebug instruction."); // Account for register pressure similar to RegPressureTracker::recede(). - RegisterOperands RegOpers(TRI, MRI); - collectOperands(MI, RegOpers); + RegisterOperands RegOpers; + RegOpers.collect(*MI, *TRI, *MRI); // Kill liveness at last uses. Assume allocatable physregs are single-use // rather than checking LiveIntervals. @@ -712,19 +924,18 @@ void RegPressureTracker::bumpDownwardPressure(const MachineInstr *MI) { if (RequireIntervals) SlotIdx = LIS->getInstructionIndex(MI).getRegSlot(); - for (unsigned i = 0, e = RegOpers.Uses.size(); i < e; ++i) { - unsigned Reg = RegOpers.Uses[i]; + for (unsigned Reg : RegOpers.Uses) { if (RequireIntervals) { // FIXME: allow the caller to pass in the list of vreg uses that remain // to be bottom-scheduled to avoid searching uses at each query. SlotIndex CurrIdx = getCurrSlot(); - const LiveInterval *LI = getInterval(Reg); - if (LI && LI->killedAt(SlotIdx) - && !findUseBetween(Reg, CurrIdx, SlotIdx, MRI, LIS)) { - decreaseRegPressure(Reg); + const LiveRange *LR = getLiveRange(*LIS, Reg); + if (LR) { + LiveQueryResult LRQ = LR->Query(SlotIdx); + if (LRQ.isKill() && !findUseBetween(Reg, CurrIdx, SlotIdx, *MRI, LIS)) + decreaseRegPressure(Reg); } - } - else if (!TargetRegisterInfo::isVirtualRegister(Reg)) { + } else if (!TargetRegisterInfo::isVirtualRegister(Reg)) { // Allocatable physregs are always single-use before register rewriting. decreaseRegPressure(Reg); } @@ -744,9 +955,14 @@ void RegPressureTracker::bumpDownwardPressure(const MachineInstr *MI) { /// register units of that pressure set introduced by this instruction. /// /// This assumes that the current LiveIn set is sufficient. +/// +/// This is expensive for an on-the-fly query because it calls +/// bumpDownwardPressure to recompute the pressure sets based on current +/// liveness. We don't yet have a fast version of downward pressure tracking +/// analogous to getUpwardPressureDelta. void RegPressureTracker:: getMaxDownwardPressureDelta(const MachineInstr *MI, RegPressureDelta &Delta, - ArrayRef CriticalPSets, + ArrayRef CriticalPSets, ArrayRef MaxPressureLimit) { // Snapshot Pressure. std::vector SavedPressure = CurrSetPressure; @@ -758,8 +974,8 @@ getMaxDownwardPressureDelta(const MachineInstr *MI, RegPressureDelta &Delta, LiveThruPressure); computeMaxPressureDelta(SavedMaxPressure, P.MaxSetPressure, CriticalPSets, MaxPressureLimit, Delta); - assert(Delta.CriticalMax.UnitIncrease >= 0 && - Delta.CurrentMax.UnitIncrease >= 0 && "cannot decrease max pressure"); + assert(Delta.CriticalMax.getUnitInc() >= 0 && + Delta.CurrentMax.getUnitInc() >= 0 && "cannot decrease max pressure"); // Restore the tracker's state. P.MaxSetPressure.swap(SavedMaxPressure);