#include "llvm/CodeGen/LiveRegMatrix.h"

Public Types
enum	InterferenceKind { IK_Free = 0 , IK_VirtReg , IK_RegUnit , IK_RegMask }

Public Member Functions
	LiveRegMatrix (LiveRegMatrix &&Other)=default
void	init (MachineFunction &MF, LiveIntervals &LIS, VirtRegMap &VRM)
void	invalidateVirtRegs ()
	Invalidate cached interference queries after modifying virtual register live ranges.
InterferenceKind	checkInterference (const LiveInterval &VirtReg, MCRegister PhysReg)
	Check for interference before assigning VirtReg to PhysReg.
bool	checkInterference (SlotIndex Start, SlotIndex End, MCRegister PhysReg)
	Check for interference in the segment [Start, End) that may prevent assignment to PhysReg.
LaneBitmask	checkInterferenceLanes (SlotIndex Start, SlotIndex End, MCRegister PhysReg)
	Check for interference in the segment [Start, End) that may prevent assignment to PhysReg, like checkInterference.
void	assign (const LiveInterval &VirtReg, MCRegister PhysReg)
	Assign VirtReg to PhysReg.
void	unassign (const LiveInterval &VirtReg, bool ClearAllReferencingSegments=false)
	Unassign VirtReg from its PhysReg.
bool	isPhysRegUsed (MCRegister PhysReg) const
	Returns true if the given `PhysReg` has any live intervals assigned.
bool	checkRegMaskInterference (const LiveInterval &VirtReg, MCRegister PhysReg=MCRegister::NoRegister)
	Check for regmask interference only.
bool	checkRegUnitInterference (const LiveInterval &VirtReg, MCRegister PhysReg)
	Check for regunit interference only.
LiveIntervalUnion::Query &	query (const LiveRange &LR, MCRegUnit RegUnit)
	Query a line of the assigned virtual register matrix directly.
LiveIntervalUnion *	getLiveUnions ()
	Directly access the live interval unions per regunit.
Register	getOneVReg (unsigned PhysReg) const
bool	isValid () const
	This checks that each LiveInterval referenced in LiveIntervalUnion actually exists in LiveIntervals and is not a dangling pointer.

Friends
class	LiveRegMatrixWrapperLegacy
class	LiveRegMatrixAnalysis

Detailed Description

Definition at line 40 of file LiveRegMatrix.h.

Member Enumeration Documentation

◆ InterferenceKind

enum llvm::LiveRegMatrix::InterferenceKind

Enumerator
IK_Free	No interference, go ahead and assign.
IK_VirtReg	Virtual register interference. There are interfering virtual registers assigned to PhysReg or its aliases. This interference could be resolved by unassigning those other virtual registers.
IK_RegUnit	Register unit interference. A fixed live range is in the way, typically argument registers for a call. This can't be resolved by unassigning other virtual registers.
IK_RegMask	RegMask interference. The live range is crossing an instruction with a regmask operand that doesn't preserve PhysReg. This typically means VirtReg is live across a call, and PhysReg isn't call-preserved.

Definition at line 84 of file LiveRegMatrix.h.

Constructor & Destructor Documentation

◆ LiveRegMatrix()

llvm::LiveRegMatrix::LiveRegMatrix ( LiveRegMatrix && Other )

default

References llvm::Other.

Member Function Documentation

◆ assign()

void LiveRegMatrix::assign	(	const LiveInterval &	VirtReg,
		MCRegister	PhysReg )

Assign VirtReg to PhysReg.

This will mark VirtReg's live range as occupied in the LiveRegMatrix and update VirtRegMap. The live range is expected to be available in PhysReg.

Definition at line 113 of file LiveRegMatrix.cpp.

References assert(), llvm::dbgs(), foreachUnit(), LLVM_DEBUG, llvm::printReg(), llvm::printRegUnit(), Range, and llvm::LiveInterval::reg().

◆ checkInterference() [1/2]

LiveRegMatrix::InterferenceKind LiveRegMatrix::checkInterference	(	const LiveInterval &	VirtReg,
		MCRegister	PhysReg )

Check for interference before assigning VirtReg to PhysReg.

If this function returns IK_Free, it is legal to assign(VirtReg, PhysReg). When there is more than one kind of interference, the InterferenceKind with the highest enum value is returned.

Definition at line 203 of file LiveRegMatrix.cpp.

References llvm::LiveIntervalUnion::Query::checkInterference(), checkRegMaskInterference(), checkRegUnitInterference(), llvm::LiveRange::empty(), foreachUnit(), IK_Free, IK_RegMask, IK_RegUnit, IK_VirtReg, and query().

◆ checkInterference() [2/2]

bool LiveRegMatrix::checkInterference	(	SlotIndex	Start,
		SlotIndex	End,
		MCRegister	PhysReg )

Check for interference in the segment [Start, End) that may prevent assignment to PhysReg.

If this function returns true, there is interference in the segment [Start, End) of some other interval already assigned to PhysReg. If this function returns false, PhysReg is free at the segment [Start, End).

Definition at line 227 of file LiveRegMatrix.cpp.

References llvm::LiveRange::addSegment(), llvm::LiveIntervalUnion::Query::checkInterference(), and llvm::LiveIntervalUnion::Query::reset().

◆ checkInterferenceLanes()

LaneBitmask LiveRegMatrix::checkInterferenceLanes	(	SlotIndex	Start,
		SlotIndex	End,
		MCRegister	PhysReg )

Check for interference in the segment [Start, End) that may prevent assignment to PhysReg, like checkInterference.

Returns a lane mask of which lanes of the physical register interfere in the segment [Start, End) of some other interval already assigned to PhysReg.

If this function returns LaneBitmask::getNone(), PhysReg is completely free at the segment [Start, End).

Definition at line 257 of file LiveRegMatrix.cpp.

References llvm::LiveRange::addSegment(), llvm::LiveIntervalUnion::Query::checkInterference(), llvm::MCRegUnitMaskIterator::isValid(), and llvm::LiveIntervalUnion::Query::reset().

◆ checkRegMaskInterference()

bool LiveRegMatrix::checkRegMaskInterference	(	const LiveInterval &	VirtReg,
		MCRegister	PhysReg = MCRegister::NoRegister )

Check for regmask interference only.

Return true if VirtReg crosses a regmask operand that clobbers PhysReg. If PhysReg is null, check if VirtReg crosses any regmask operands.

Definition at line 162 of file LiveRegMatrix.cpp.

References llvm::MCRegister::id(), and llvm::LiveInterval::reg().

Referenced by checkInterference().

◆ checkRegUnitInterference()

bool LiveRegMatrix::checkRegUnitInterference	(	const LiveInterval &	VirtReg,
		MCRegister	PhysReg )

Check for regunit interference only.

Return true if VirtReg overlaps a fixed assignment of one of PhysRegs's register units.

Definition at line 181 of file LiveRegMatrix.cpp.

References llvm::LiveRange::empty(), foreachUnit(), Range, and llvm::LiveInterval::reg().

Referenced by checkInterference().

◆ getLiveUnions()

LiveIntervalUnion * llvm::LiveRegMatrix::getLiveUnions ( )

inline

Directly access the live interval unions per regunit.

This returns an array indexed by the regunit number.

Definition at line 175 of file LiveRegMatrix.h.

◆ getOneVReg()

Register LiveRegMatrix::getOneVReg ( unsigned PhysReg ) const

Definition at line 292 of file LiveRegMatrix.cpp.

References getOneVReg(), llvm::MCRegister::NoRegister, and llvm::LiveInterval::reg().

Referenced by getOneVReg().

◆ init()

void LiveRegMatrix::init	(	MachineFunction &	MF,
		LiveIntervals &	LIS,
		VirtRegMap &	VRM )

Definition at line 62 of file LiveRegMatrix.cpp.

References llvm::TargetSubtargetInfo::getRegisterInfo(), llvm::MachineFunction::getSubtarget(), llvm::VirtRegMap::init(), and invalidateVirtRegs().

Referenced by llvm::LiveRegMatrixAnalysis::run().

◆ invalidateVirtRegs()

void llvm::LiveRegMatrix::invalidateVirtRegs ( )

inline

Invalidate cached interference queries after modifying virtual register live ranges.

Interference checks may return stale information unless caches are invalidated.

Definition at line 82 of file LiveRegMatrix.h.

Referenced by init().

◆ isPhysRegUsed()

bool LiveRegMatrix::isPhysRegUsed ( MCRegister PhysReg ) const

Returns true if the given PhysReg has any live intervals assigned.

Definition at line 154 of file LiveRegMatrix.cpp.

◆ isValid()

bool LiveRegMatrix::isValid ( ) const

This checks that each LiveInterval referenced in LiveIntervalUnion actually exists in LiveIntervals and is not a dangling pointer.

Definition at line 303 of file LiveRegMatrix.cpp.

References llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::contains(), llvm::dbgs(), I, llvm::Register::index2VirtReg(), llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::insert(), llvm::printRegUnit(), and Size.

◆ query()

LiveIntervalUnion::Query & LiveRegMatrix::query	(	const LiveRange &	LR,
		MCRegUnit	RegUnit )

Query a line of the assigned virtual register matrix directly.

Use MCRegUnitIterator to enumerate all regunits in the desired PhysReg. This returns a reference to an internal Query data structure that is only valid until the next query() call.

Definition at line 195 of file LiveRegMatrix.cpp.

References llvm::LiveIntervalUnion::Query::init().

Referenced by checkInterference().

◆ unassign()

void LiveRegMatrix::unassign	(	const LiveInterval &	VirtReg,
		bool	ClearAllReferencingSegments = false )

Unassign VirtReg from its PhysReg.

Assuming that VirtReg was previously assigned to a PhysReg, this undoes the assignment and updates VirtRegMap accordingly. ClearAllReferencingSegments changes the way segments are removed from the matrix:

If false (default), only segments that exactly match VirtReg's live range are removed.
If true, all segments that reference VirtReg are removed. This is useful when VirtReg's live range(s) is already empty.

Definition at line 130 of file LiveRegMatrix.cpp.

References llvm::dbgs(), foreachUnit(), LLVM_DEBUG, llvm::printReg(), llvm::printRegUnit(), Range, and llvm::LiveInterval::reg().