class LiveRangeEdit

Declaration

class LiveRangeEdit : private Delegate { /* full declaration omitted */ };

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:43

Inherits from: MachineRegisterInfo::Delegate

Member Variables

private const llvm::LiveInterval* const Parent
private SmallVectorImpl<llvm::Register>& NewRegs
private llvm::MachineRegisterInfo& MRI
private llvm::LiveIntervals& LIS
private llvm::VirtRegMap* VRM
private const llvm::TargetInstrInfo& TII
private llvm::LiveRangeEdit::Delegate* const TheDelegate
private const unsigned int FirstNew
FirstNew - Index of the first register added to NewRegs.
private bool ScannedRemattable = false
ScannedRemattable - true when remattable values have been identified.
private SmallPtrSet<llvm::MachineInstr*, 32>* DeadRemats
DeadRemats - The saved instructions which have already been dead after rematerialization but not deleted yet -- to be done in postOptimization.
private SmallPtrSet<const llvm::VNInfo*, 4> Remattable
Remattable - Values defined by remattable instructions as identified by tii.isTriviallyReMaterializable().
private SmallPtrSet<const llvm::VNInfo*, 4> Rematted
Rematted - Values that were actually rematted, and so need to have their live range trimmed or entirely removed.

Method Overview

  • public LiveRangeEdit(const llvm::LiveInterval * parent, SmallVectorImpl<llvm::Register> & newRegs, llvm::MachineFunction & MF, llvm::LiveIntervals & lis, llvm::VirtRegMap * vrm, llvm::LiveRangeEdit::Delegate * delegate = nullptr, SmallPtrSet<llvm::MachineInstr *, 32> * deadRemats = nullptr)
  • private void MRI_NoteNewVirtualRegister(llvm::Register VReg)
  • public bool allUsesAvailableAt(const llvm::MachineInstr * OrigMI, llvm::SlotIndex OrigIdx, llvm::SlotIndex UseIdx) const
  • public bool anyRematerializable()
  • public llvm::LiveRangeEdit::iterator begin() const
  • public void calculateRegClassAndHint(llvm::MachineFunction &, llvm::VirtRegAuxInfo &)
  • public bool canRematerializeAt(llvm::LiveRangeEdit::Remat & RM, llvm::VNInfo * OrigVNI, llvm::SlotIndex UseIdx, bool cheapAsAMove)
  • public bool checkRematerializable(llvm::VNInfo * VNI, const llvm::MachineInstr * DefMI)
  • public llvm::Register create()
  • public llvm::LiveInterval & createEmptyInterval()
  • private llvm::LiveInterval & createEmptyIntervalFrom(llvm::Register OldReg, bool createSubRanges)
  • public llvm::Register createFrom(llvm::Register OldReg)
  • public bool didRematerialize(const llvm::VNInfo * ParentVNI) const
  • private void eliminateDeadDef(llvm::MachineInstr * MI, llvm::LiveRangeEdit::ToShrinkSet & ToShrink)
  • public void eliminateDeadDefs(SmallVectorImpl<llvm::MachineInstr *> & Dead, ArrayRef<llvm::Register> RegsBeingSpilled = None)
  • public bool empty() const
  • public llvm::LiveRangeEdit::iterator end() const
  • public void eraseVirtReg(llvm::Register Reg)
  • private bool foldAsLoad(llvm::LiveInterval * LI, SmallVectorImpl<llvm::MachineInstr *> & Dead)
  • public llvm::Register get(unsigned int idx) const
  • public const llvm::LiveInterval & getParent() const
  • public llvm::Register getReg() const
  • public void markRematerialized(const llvm::VNInfo * ParentVNI)
  • public void pop_back()
  • public ArrayRef<llvm::Register> regs() const
  • public llvm::SlotIndex rematerializeAt(llvm::MachineBasicBlock & MBB, MachineBasicBlock::iterator MI, unsigned int DestReg, const llvm::LiveRangeEdit::Remat & RM, const llvm::TargetRegisterInfo &, bool Late = false)
  • private void scanRemattable()
  • public unsigned int size() const
  • private bool useIsKill(const llvm::LiveInterval & LI, const llvm::MachineOperand & MO) const
  • public ~LiveRangeEdit()

Methods

LiveRangeEdit(
    const llvm::LiveInterval* parent,
    SmallVectorImpl<llvm::Register>& newRegs,
    llvm::MachineFunction& MF,
    llvm::LiveIntervals& lis,
    llvm::VirtRegMap* vrm,
    llvm::LiveRangeEdit::Delegate* delegate =
        nullptr,
    SmallPtrSet<llvm::MachineInstr*, 32>*
        deadRemats = nullptr)

Description

Create a LiveRangeEdit for breaking down parent into smaller pieces.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:130

Parameters

const llvm::LiveInterval* parent
The register being spilled or split.
SmallVectorImpl<llvm::Register>& newRegs
List to receive any new registers created. This needn't be empty initially, any existing registers are ignored.
llvm::MachineFunction& MF
The MachineFunction the live range edit is taking place in.
llvm::LiveIntervals& lis
The collection of all live intervals in this function.
llvm::VirtRegMap* vrm
Map of virtual registers to physical registers for this function. If NULL, no virtual register map updates will be done. This could be the case if called before Regalloc.
llvm::LiveRangeEdit::Delegate* delegate = nullptr
SmallPtrSet<llvm::MachineInstr*, 32>* deadRemats = nullptr
The collection of all the instructions defining an original reg and are dead after remat.

void MRI_NoteNewVirtualRegister(
    llvm::Register VReg)

Description

MachineRegisterInfo callback to notify when new virtual registers are created.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:109

Parameters

llvm::Register VReg

bool allUsesAvailableAt(
    const llvm::MachineInstr* OrigMI,
    llvm::SlotIndex OrigIdx,
    llvm::SlotIndex UseIdx) const

Description

allUsesAvailableAt - Return true if all registers used by OrigMI at OrigIdx are also available with the same value at UseIdx.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:202

Parameters

const llvm::MachineInstr* OrigMI
llvm::SlotIndex OrigIdx
llvm::SlotIndex UseIdx

bool anyRematerializable()

Description

anyRematerializable - Return true if any parent values may be rematerializable. This function must be called before any rematerialization is attempted.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:185

llvm::LiveRangeEdit::iterator begin() const

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:151

void calculateRegClassAndHint(
    llvm::MachineFunction&,
    llvm::VirtRegAuxInfo&)

Description

calculateRegClassAndHint - Recompute register class and hint for each new register.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:246

Parameters

llvm::MachineFunction&
llvm::VirtRegAuxInfo& 

bool canRematerializeAt(
    llvm::LiveRangeEdit::Remat& RM,
    llvm::VNInfo* OrigVNI,
    llvm::SlotIndex UseIdx,
    bool cheapAsAMove)

Description

canRematerializeAt - Determine if ParentVNI can be rematerialized at UseIdx. It is assumed that parent_.getVNINfoAt(UseIdx) == ParentVNI. When cheapAsAMove is set, only cheap remats are allowed.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:208

Parameters

llvm::LiveRangeEdit::Remat& RM
llvm::VNInfo* OrigVNI
llvm::SlotIndex UseIdx
bool cheapAsAMove

bool checkRematerializable(
    llvm::VNInfo* VNI,
    const llvm::MachineInstr* DefMI)

Description

checkRematerializable - Manually add VNI to the list of rematerializable values if DefMI may be rematerializable.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:189

Parameters

llvm::VNInfo* VNI
const llvm::MachineInstr* DefMI

llvm::Register create()

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:180

llvm::LiveInterval& createEmptyInterval()

Description

create - Create a new register with the same class and original slot as parent.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:176

llvm::LiveInterval& createEmptyIntervalFrom(
    llvm::Register OldReg,
    bool createSubRanges)

Description

Create a new empty interval based on OldReg.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:116

Parameters

llvm::Register OldReg
bool createSubRanges

llvm::Register createFrom(llvm::Register OldReg)

Description

createFrom - Create a new virtual register based on OldReg.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:172

Parameters

llvm::Register OldReg

bool didRematerialize(
    const llvm::VNInfo* ParentVNI) const

Description

didRematerialize - Return true if ParentVNI was rematerialized anywhere.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:227

Parameters

const llvm::VNInfo* ParentVNI

void eliminateDeadDef(
    llvm::MachineInstr* MI,
    llvm::LiveRangeEdit::ToShrinkSet& ToShrink)

Description

Helper for eliminateDeadDefs.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:105

Parameters

llvm::MachineInstr* MI
llvm::LiveRangeEdit::ToShrinkSet& ToShrink

void eliminateDeadDefs(
    SmallVectorImpl<llvm::MachineInstr*>& Dead,
    ArrayRef<llvm::Register> RegsBeingSpilled =
        None)

Description

eliminateDeadDefs - Try to delete machine instructions that are now dead (allDefsAreDead returns true). This may cause live intervals to be trimmed and further dead efs to be eliminated. RegsBeingSpilled lists registers currently being spilled by the register allocator. These registers should not be split into new intervals as currently those new intervals are not guaranteed to spill.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:241

Parameters

SmallVectorImpl<llvm::MachineInstr*>& Dead
ArrayRef<llvm::Register> RegsBeingSpilled = None

bool empty() const

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:154

llvm::LiveRangeEdit::iterator end() const

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:152

void eraseVirtReg(llvm::Register Reg)

Description

eraseVirtReg - Notify the delegate that Reg is no longer in use, and try to erase it from LIS.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:233

Parameters

llvm::Register Reg

bool foldAsLoad(
    llvm::LiveInterval* LI,
    SmallVectorImpl<llvm::MachineInstr*>& Dead)

Description

foldAsLoad - If LI has a single use and a single def that can be folded as a load, eliminate the register by folding the def into the use.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:99

Parameters

llvm::LiveInterval* LI
SmallVectorImpl<llvm::MachineInstr*>& Dead

llvm::Register get(unsigned int idx) const

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:155

Parameters

unsigned int idx

const llvm::LiveInterval& getParent() const

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:142

llvm::Register getReg() const

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:147

void markRematerialized(
    const llvm::VNInfo* ParentVNI)

Description

markRematerialized - explicitly mark a value as rematerialized after doing it manually.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:222

Parameters

const llvm::VNInfo* ParentVNI

void pop_back()

Description

pop_back - It allows LiveRangeEdit users to drop new registers. The context is when an original def instruction of a register is dead after rematerialization, we still want to keep it for following rematerializations. We save the def instruction in DeadRemats, and replace the original dst register with a new dummy register so the live range of original dst register can be shrinked normally. We don't want to allocate phys register for the dummy register, so we want to drop it from the NewRegs set.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:165

ArrayRef<llvm::Register> regs() const

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:167

llvm::SlotIndex rematerializeAt(
    llvm::MachineBasicBlock& MBB,
    MachineBasicBlock::iterator MI,
    unsigned int DestReg,
    const llvm::LiveRangeEdit::Remat& RM,
    const llvm::TargetRegisterInfo&,
    bool Late = false)

Description

rematerializeAt - Rematerialize RM.ParentVNI into DestReg by inserting an instruction into MBB before MI. The new instruction is mapped, but liveness is not updated. Return the SlotIndex of the new instruction.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:215

Parameters

llvm::MachineBasicBlock& MBB
MachineBasicBlock::iterator MI
unsigned int DestReg
const llvm::LiveRangeEdit::Remat& RM
const llvm::TargetRegisterInfo&
bool Late = false

void scanRemattable()

Description

scanRemattable - Identify the Parent values that may rematerialize.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:95

unsigned int size() const

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:153

bool useIsKill(
    const llvm::LiveInterval& LI,
    const llvm::MachineOperand& MO) const

Description

Check if MachineOperand \p MO is a last use/kill either in the main live range of \p LI or in one of the matching subregister ranges.

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:113

Parameters

const llvm::LiveInterval& LI
const llvm::MachineOperand& MO

~LiveRangeEdit()

Declared at: llvm/include/llvm/CodeGen/LiveRangeEdit.h:140