class RegPressureTracker

Declaration

class RegPressureTracker { /* full declaration omitted */ };

Description

Track the current register pressure at some position in the instruction stream, and remember the high water mark within the region traversed. This does not automatically consider live-through ranges. The client may independently adjust for global liveness. Each RegPressureTracker only works within a MachineBasicBlock. Pressure can be tracked across a larger region by storing a RegisterPressure result at each block boundary and explicitly adjusting pressure to account for block live-in and live-out register sets. RegPressureTracker holds a reference to a RegisterPressure result that it computes incrementally. During downward tracking, P.BottomIdx or P.BottomPos is invalid until it reaches the end of the block or closeRegion() is explicitly called. Similarly, P.TopIdx is invalid during upward tracking. Changing direction has the side effect of closing region, and traversing past TopIdx or BottomIdx reopens it.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:358

Method Overview

• public RegPressureTracker(llvm::RegionPressure & rp)
• public RegPressureTracker(llvm::IntervalPressure & rp)
• public void addLiveRegs(ArrayRef<llvm::RegisterMaskPair> Regs)
• public void advance(const llvm::RegisterOperands & RegOpers)
• public void advance()
• protected void bumpDeadDefs(ArrayRef<llvm::RegisterMaskPair> DeadDefs)
• protected void bumpDownwardPressure(const llvm::MachineInstr * MI)
• protected void bumpUpwardPressure(const llvm::MachineInstr * MI)
• public void closeBottom()
• public void closeRegion()
• public void closeTop()
• protected void decreaseRegPressure(unsigned int RegUnit, llvm::LaneBitmask PreviousMask, llvm::LaneBitmask NewMask)
• protected void discoverLiveIn(llvm::RegisterMaskPair Pair)
• protected void discoverLiveInOrOut(llvm::RegisterMaskPair Pair, SmallVectorImpl<llvm::RegisterMaskPair> & LiveInOrOut)
• protected void discoverLiveOut(llvm::RegisterMaskPair Pair)
• public void dump() const
• protected llvm::SlotIndex getCurrSlot() const
• public void getDownwardPressure(const llvm::MachineInstr * MI, std::vector<unsigned int> & PressureResult, std::vector<unsigned int> & MaxPressureResult)
• protected llvm::LaneBitmask getLastUsedLanes(unsigned int RegUnit, llvm::SlotIndex Pos) const
• protected llvm::LaneBitmask getLiveLanesAt(unsigned int RegUnit, llvm::SlotIndex Pos) const
• protected llvm::LaneBitmask getLiveThroughAt(unsigned int RegUnit, llvm::SlotIndex Pos) const
• public ArrayRef<unsigned int> getLiveThru() const
• public void getMaxDownwardPressureDelta(const llvm::MachineInstr * MI, llvm::RegPressureDelta & Delta, ArrayRef<llvm::PressureChange> CriticalPSets, ArrayRef<unsigned int> MaxPressureLimit)
• public void getMaxPressureDelta(const llvm::MachineInstr * MI, llvm::RegPressureDelta & Delta, ArrayRef<llvm::PressureChange> CriticalPSets, ArrayRef<unsigned int> MaxPressureLimit)
• public void getMaxUpwardPressureDelta(const llvm::MachineInstr * MI, llvm::PressureDiff * PDiff, llvm::RegPressureDelta & Delta, ArrayRef<llvm::PressureChange> CriticalPSets, ArrayRef<unsigned int> MaxPressureLimit)
• public MachineBasicBlock::const_iterator getPos() const
• public const llvm::RegisterPressure & getPressure() const
• public llvm::RegisterPressure & getPressure()
• public void getPressureAfterInst(const llvm::MachineInstr * MI, std::vector<unsigned int> & PressureResult, std::vector<unsigned int> & MaxPressureResult)
• public const std::vector<unsigned int> & getRegSetPressureAtPos() const
• public void getUpwardPressure(const llvm::MachineInstr * MI, std::vector<unsigned int> & PressureResult, std::vector<unsigned int> & MaxPressureResult)
• public void getUpwardPressureDelta(const llvm::MachineInstr * MI, llvm::PressureDiff & PDiff, llvm::RegPressureDelta & Delta, ArrayRef<llvm::PressureChange> CriticalPSets, ArrayRef<unsigned int> MaxPressureLimit) const
• public bool hasUntiedDef(unsigned int VirtReg) const
• protected void increaseRegPressure(unsigned int RegUnit, llvm::LaneBitmask PreviousMask, llvm::LaneBitmask NewMask)
• public void init(const llvm::MachineFunction * mf, const llvm::RegisterClassInfo * rci, const llvm::LiveIntervals * lis, const llvm::MachineBasicBlock * mbb, MachineBasicBlock::const_iterator pos, bool TrackLaneMasks, bool TrackUntiedDefs)
• public void initLiveThru(ArrayRef<unsigned int> PressureSet)
• public void initLiveThru(const llvm::RegPressureTracker & RPTracker)
• public bool isBottomClosed() const
• public bool isTopClosed() const
• public void recede(SmallVectorImpl<llvm::RegisterMaskPair> * LiveUses = nullptr)
• public void recede(const llvm::RegisterOperands & RegOpers, SmallVectorImpl<llvm::RegisterMaskPair> * LiveUses = nullptr)
• public void recedeSkipDebugValues()
• public void reset()
• public void setPos(MachineBasicBlock::const_iterator Pos)

Methods

¶RegPressureTracker(llvm::RegionPressure& rp)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:399

Parameters

llvm::RegionPressure& rp

¶RegPressureTracker(llvm::IntervalPressure& rp)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:398

Parameters

llvm::IntervalPressure& rp

¶void addLiveRegs(
    ArrayRef<llvm::RegisterMaskPair> Regs)

Description

Force liveness of virtual registers or physical register units. Particularly useful to initialize the livein/out state of the tracker before the first call to advance/recede.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:411

Parameters

ArrayRef<llvm::RegisterMaskPair> Regs

¶void advance(
    const llvm::RegisterOperands& RegOpers)

Description

Advance across the current instruction. This is a "low-level" variant of advance() which takes precomputed RegisterOperands of the instruction.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:441

Parameters

const llvm::RegisterOperands& RegOpers

¶void advance()

Description

Advance across the current instruction.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:436

¶void bumpDeadDefs(
    ArrayRef<llvm::RegisterMaskPair> DeadDefs)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:556

Parameters

ArrayRef<llvm::RegisterMaskPair> DeadDefs

¶void bumpDownwardPressure(
    const llvm::MachineInstr* MI)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:559

Parameters

const llvm::MachineInstr* MI

¶void bumpUpwardPressure(
    const llvm::MachineInstr* MI)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:558

Parameters

const llvm::MachineInstr* MI

¶void closeBottom()

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:472

¶void closeRegion()

Description

Finalize the region boundaries and recored live ins and live outs.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:444

¶void closeTop()

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:471

¶void decreaseRegPressure(
    unsigned int RegUnit,
    llvm::LaneBitmask PreviousMask,
    llvm::LaneBitmask NewMask)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:553

Parameters

unsigned int RegUnit

llvm::LaneBitmask PreviousMask

llvm::LaneBitmask NewMask

¶void discoverLiveIn(llvm::RegisterMaskPair Pair)

Description

Add Reg to the live in set and increase max pressure.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:545

Parameters

llvm::RegisterMaskPair Pair

¶void discoverLiveInOrOut(
    llvm::RegisterMaskPair Pair,
    SmallVectorImpl<llvm::RegisterMaskPair>&
        LiveInOrOut)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:561

Parameters

llvm::RegisterMaskPair Pair

SmallVectorImpl<llvm::RegisterMaskPair>& LiveInOrOut

¶void discoverLiveOut(llvm::RegisterMaskPair Pair)

Description

Add Reg to the live out set and increase max pressure.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:543

Parameters

llvm::RegisterMaskPair Pair

¶void dump() const

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:539

¶llvm::SlotIndex getCurrSlot() const

Description

Get the SlotIndex for the first nondebug instruction including or after the current position.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:549

¶void getDownwardPressure(
    const llvm::MachineInstr* MI,
    std::vector<unsigned int>& PressureResult,
    std::vector<unsigned int>& MaxPressureResult)

Description

Get the pressure of each PSet after traversing this instruction top-down.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:521

Parameters

const llvm::MachineInstr* MI

std::vector<unsigned int>& PressureResult

std::vector<unsigned int>& MaxPressureResult

¶llvm::LaneBitmask getLastUsedLanes(
    unsigned int RegUnit,
    llvm::SlotIndex Pos) const

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:564

Parameters

unsigned int RegUnit

llvm::SlotIndex Pos

¶llvm::LaneBitmask getLiveLanesAt(
    unsigned int RegUnit,
    llvm::SlotIndex Pos) const

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:565

Parameters

unsigned int RegUnit

llvm::SlotIndex Pos

¶llvm::LaneBitmask getLiveThroughAt(
    unsigned int RegUnit,
    llvm::SlotIndex Pos) const

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:566

Parameters

unsigned int RegUnit

llvm::SlotIndex Pos

¶ArrayRef<unsigned int> getLiveThru() const

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:455

¶void getMaxDownwardPressureDelta(
    const llvm::MachineInstr* MI,
    llvm::RegPressureDelta& Delta,
    ArrayRef<llvm::PressureChange> CriticalPSets,
    ArrayRef<unsigned int> MaxPressureLimit)

Description

Consider the pressure increase caused by traversing this instruction top-down. Find the pressure set with the most change beyond its pressure limit based on the tracker's current pressure, and record the number of excess register units of that pressure set introduced by this instruction.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:494

Parameters

const llvm::MachineInstr* MI

llvm::RegPressureDelta& Delta

ArrayRef<llvm::PressureChange> CriticalPSets

ArrayRef<unsigned int> MaxPressureLimit

¶void getMaxPressureDelta(
    const llvm::MachineInstr* MI,
    llvm::RegPressureDelta& Delta,
    ArrayRef<llvm::PressureChange> CriticalPSets,
    ArrayRef<unsigned int> MaxPressureLimit)

Description

Find the pressure set with the most change beyond its pressure limit after traversing this instruction either upward or downward depending on the closed end of the current region.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:502

Parameters

const llvm::MachineInstr* MI

llvm::RegPressureDelta& Delta

ArrayRef<llvm::PressureChange> CriticalPSets

ArrayRef<unsigned int> MaxPressureLimit

¶void getMaxUpwardPressureDelta(
    const llvm::MachineInstr* MI,
    llvm::PressureDiff* PDiff,
    llvm::RegPressureDelta& Delta,
    ArrayRef<llvm::PressureChange> CriticalPSets,
    ArrayRef<unsigned int> MaxPressureLimit)

Description

Consider the pressure increase caused by traversing this instruction bottom-up. Find the pressure set with the most change beyond its pressure limit based on the tracker's current pressure, and record the number of excess register units of that pressure set introduced by this instruction.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:478

Parameters

const llvm::MachineInstr* MI

llvm::PressureDiff* PDiff

llvm::RegPressureDelta& Delta

ArrayRef<llvm::PressureChange> CriticalPSets

ArrayRef<unsigned int> MaxPressureLimit

¶MachineBasicBlock::const_iterator getPos() const

Description

Get the MI position corresponding to this register pressure.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:414

¶const llvm::RegisterPressure& getPressure() const

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:460

¶llvm::RegisterPressure& getPressure()

Description

Get the resulting register pressure over the traversed region. This result is complete if closeRegion() was explicitly invoked.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:459

¶void getPressureAfterInst(
    const llvm::MachineInstr* MI,
    std::vector<unsigned int>& PressureResult,
    std::vector<unsigned int>& MaxPressureResult)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:525

Parameters

const llvm::MachineInstr* MI

std::vector<unsigned int>& PressureResult

std::vector<unsigned int>& MaxPressureResult

¶const std::vector<unsigned int>&
getRegSetPressureAtPos() const

Description

Get the register set pressure at the current position, which may be less than the pressure across the traversed region.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:464

¶void getUpwardPressure(
    const llvm::MachineInstr* MI,
    std::vector<unsigned int>& PressureResult,
    std::vector<unsigned int>& MaxPressureResult)

Description

Get the pressure of each PSet after traversing this instruction bottom-up.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:516

Parameters

const llvm::MachineInstr* MI

std::vector<unsigned int>& PressureResult

std::vector<unsigned int>& MaxPressureResult

¶void getUpwardPressureDelta(
    const llvm::MachineInstr* MI,
    llvm::PressureDiff& PDiff,
    llvm::RegPressureDelta& Delta,
    ArrayRef<llvm::PressureChange> CriticalPSets,
    ArrayRef<unsigned int> MaxPressureLimit) const

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:484

Parameters

const llvm::MachineInstr* MI

llvm::PressureDiff& PDiff

llvm::RegPressureDelta& Delta

ArrayRef<llvm::PressureChange> CriticalPSets

ArrayRef<unsigned int> MaxPressureLimit

¶bool hasUntiedDef(unsigned int VirtReg) const

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:535

Parameters

unsigned int VirtReg

¶void increaseRegPressure(
    unsigned int RegUnit,
    llvm::LaneBitmask PreviousMask,
    llvm::LaneBitmask NewMask)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:551

Parameters

unsigned int RegUnit

llvm::LaneBitmask PreviousMask

llvm::LaneBitmask NewMask

¶void init(const llvm::MachineFunction* mf,
          const llvm::RegisterClassInfo* rci,
          const llvm::LiveIntervals* lis,
          const llvm::MachineBasicBlock* mbb,
          MachineBasicBlock::const_iterator pos,
          bool TrackLaneMasks,
          bool TrackUntiedDefs)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:403

Parameters

const llvm::MachineFunction* mf

const llvm::RegisterClassInfo* rci

const llvm::LiveIntervals* lis

const llvm::MachineBasicBlock* mbb

MachineBasicBlock::const_iterator pos

bool TrackLaneMasks

bool TrackUntiedDefs

¶void initLiveThru(
    ArrayRef<unsigned int> PressureSet)

Description

Copy an existing live thru pressure result.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:451

Parameters

ArrayRef<unsigned int> PressureSet

¶void initLiveThru(
    const llvm::RegPressureTracker& RPTracker)

Description

Initialize the LiveThru pressure set based on the untied defs found in RPTracker.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:448

Parameters

const llvm::RegPressureTracker& RPTracker

¶bool isBottomClosed() const

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:469

¶bool isTopClosed() const

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:468

¶void recede(
    SmallVectorImpl<llvm::RegisterMaskPair>*
        LiveUses = nullptr)

Description

Recede across the previous instruction.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:423

Parameters

SmallVectorImpl<llvm::RegisterMaskPair>* LiveUses = nullptr

¶void recede(
    const llvm::RegisterOperands& RegOpers,
    SmallVectorImpl<llvm::RegisterMaskPair>*
        LiveUses = nullptr)

Description

Recede across the previous instruction. This "low-level" variant assumes that recedeSkipDebugValues() was called previously and takes precomputed RegisterOperands for the instruction.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:429

Parameters

const llvm::RegisterOperands& RegOpers

SmallVectorImpl<llvm::RegisterMaskPair>* LiveUses = nullptr

¶void recedeSkipDebugValues()

Description

Recede until we find an instruction which is not a DebugValue.

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:433

¶void reset()

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:401

¶void setPos(MachineBasicBlock::const_iterator Pos)

Declared at: llvm/include/llvm/CodeGen/RegisterPressure.h:420

Parameters

MachineBasicBlock::const_iterator Pos