A set of register units used to track register liveness. More...

#include "llvm/CodeGen/LiveRegUnits.h"

Public Member Functions
	LiveRegUnits ()=default
	Constructs a new empty LiveRegUnits set.

	LiveRegUnits (const TargetRegisterInfo &TRI)
	Constructs and initialize an empty LiveRegUnits set.

void	init (const TargetRegisterInfo &TRI)
	Initialize and clear the set.

void	clear ()
	Clears the set.

bool	empty () const
	Returns true if the set is empty.

void	addReg (MCPhysReg Reg)
	Adds register units covered by physical register `Reg`.

void	addRegMasked (MCPhysReg Reg, LaneBitmask Mask)
	Adds register units covered by physical register `Reg` that are part of the lanemask `Mask`.

void	removeReg (MCPhysReg Reg)
	Removes all register units covered by physical register `Reg`.

void	removeRegsNotPreserved (const uint32_t *RegMask)
	Removes register units not preserved by the regmask `RegMask`.

void	addRegsInMask (const uint32_t *RegMask)
	Adds register units not preserved by the regmask `RegMask`.

bool	available (MCPhysReg Reg) const
	Returns true if no part of physical register `Reg` is live.

void	stepBackward (const MachineInstr &MI)
	Updates liveness when stepping backwards over the instruction `MI`.

void	accumulate (const MachineInstr &MI)
	Adds all register units used, defined or clobbered in `MI`.

void	addLiveOuts (const MachineBasicBlock &MBB)
	Adds registers living out of block `MBB`.

void	addLiveIns (const MachineBasicBlock &MBB)
	Adds registers living into block `MBB`.

void	addUnits (const BitVector &RegUnits)
	Adds all register units marked in the bitvector `RegUnits`.

void	removeUnits (const BitVector &RegUnits)
	Removes all register units marked in the bitvector `RegUnits`.

const BitVector &	getBitVector () const
	Return the internal bitvector representation of the set.

Static Public Member Functions
static void	accumulateUsedDefed (const MachineInstr &MI, LiveRegUnits &ModifiedRegUnits, LiveRegUnits &UsedRegUnits, const TargetRegisterInfo *TRI)
	For a machine instruction `MI`, adds all register units used in `UsedRegUnits` and defined or clobbered in `ModifiedRegUnits`.

Detailed Description

A set of register units used to track register liveness.

Definition at line 30 of file LiveRegUnits.h.

Constructor & Destructor Documentation

◆ LiveRegUnits() [1/2]

llvm::LiveRegUnits::LiveRegUnits ( )

default

Constructs a new empty LiveRegUnits set.

◆ LiveRegUnits() [2/2]

llvm::LiveRegUnits::LiveRegUnits ( const TargetRegisterInfo & TRI )

inline

Constructs and initialize an empty LiveRegUnits set.

Definition at line 39 of file LiveRegUnits.h.

References init(), and TRI.

Member Function Documentation

◆ accumulate()

void LiveRegUnits::accumulate ( const MachineInstr & MI )

Adds all register units used, defined or clobbered in MI.

This is useful when walking over a range of instruction to find registers unused over the whole range.

Definition at line 69 of file LiveRegUnits.cpp.

References addReg(), addRegsInMask(), and MI.

Referenced by canRenameUntilSecondLoad(), canRenameUpToDef(), and llvm::ARMBaseInstrInfo::isMBBSafeToOutlineFrom().

◆ accumulateUsedDefed()

static void llvm::LiveRegUnits::accumulateUsedDefed	(	const MachineInstr &	MI,
		LiveRegUnits &	ModifiedRegUnits,
		LiveRegUnits &	UsedRegUnits,
		const TargetRegisterInfo *	TRI
	)

inlinestatic

For a machine instruction MI, adds all register units used in UsedRegUnits and defined or clobbered in ModifiedRegUnits.

This is useful when walking over a range of instructions to track registers used or defined separately.

Definition at line 47 of file LiveRegUnits.h.

References addReg(), addRegsInMask(), assert(), MI, Reg, and TRI.

Referenced by llvm::HexagonRegisterInfo::eliminateFrameIndex(), and INITIALIZE_PASS().

◆ addLiveIns()

void LiveRegUnits::addLiveIns ( const MachineBasicBlock & MBB )

Adds registers living into block MBB.

Definition at line 155 of file LiveRegUnits.cpp.

References addBlockLiveIns(), llvm::MachineBasicBlock::getParent(), and MBB.

Referenced by llvm::SIFrameLowering::emitPrologue(), llvm::RegScavenger::enterBasicBlock(), and initLiveUnits().

◆ addLiveOuts()

void LiveRegUnits::addLiveOuts ( const MachineBasicBlock & MBB )

Adds registers living out of block MBB.

Live out registers are the union of the live-in registers of the successor blocks and pristine registers. Live out registers of the end block are the callee saved registers.

Definition at line 138 of file LiveRegUnits.cpp.

References addBlockLiveIns(), addCalleeSavedRegs(), llvm::MachineFunction::getFrameInfo(), llvm::MachineBasicBlock::getParent(), llvm::MachineFrameInfo::isCalleeSavedInfoValid(), llvm::MachineBasicBlock::isReturnBlock(), MBB, and llvm::MachineBasicBlock::successors().

Referenced by llvm::Thumb1InstrInfo::copyPhysReg(), llvm::RegScavenger::enterBasicBlockEnd(), llvm::ScheduleDAGInstrs::fixupKills(), llvm::ReachingDefAnalysis::getLiveOuts(), llvm::ReachingDefAnalysis::getLocalLiveOutMIDef(), llvm::AArch64InstrInfo::getOutlinableRanges(), initLiveUnits(), llvm::ARMBaseInstrInfo::isMBBSafeToOutlineFrom(), llvm::ReachingDefAnalysis::isReachingDefLiveOut(), llvm::ReachingDefAnalysis::isRegUsedAfter(), and llvm::SystemZInstrInfo::prepareCompareSwapOperands().