SplitEditor - Edit machine code and LiveIntervals for live range splitting. More...

#include "CodeGen/SplitKit.h"

Public Types
enum	ComplementSpillMode { SM_Partition , SM_Size , SM_Speed }
	ComplementSpillMode - Select how the complement live range should be created. More...

Public Member Functions
	SplitEditor (SplitAnalysis &SA, LiveIntervals &LIS, VirtRegMap &VRM, MachineDominatorTree &MDT, MachineBlockFrequencyInfo &MBFI, VirtRegAuxInfo &VRAI)
	Create a new SplitEditor for editing the LiveInterval analyzed by SA.

void	reset (LiveRangeEdit &, ComplementSpillMode=SM_Partition)
	reset - Prepare for a new split.

unsigned	openIntv ()
	Create a new virtual register and live interval.

unsigned	currentIntv () const
	currentIntv - Return the current interval index.

void	selectIntv (unsigned Idx)
	selectIntv - Select a previously opened interval index.

SlotIndex	enterIntvBefore (SlotIndex Idx)
	enterIntvBefore - Enter the open interval before the instruction at Idx.

SlotIndex	enterIntvAfter (SlotIndex Idx)
	enterIntvAfter - Enter the open interval after the instruction at Idx.

SlotIndex	enterIntvAtEnd (MachineBasicBlock &MBB)
	enterIntvAtEnd - Enter the open interval at the end of MBB.

void	useIntv (const MachineBasicBlock &MBB)
	useIntv - indicate that all instructions in MBB should use OpenLI.

void	useIntv (SlotIndex Start, SlotIndex End)
	useIntv - indicate that all instructions in range should use OpenLI.

SlotIndex	leaveIntvAfter (SlotIndex Idx)
	leaveIntvAfter - Leave the open interval after the instruction at Idx.

SlotIndex	leaveIntvBefore (SlotIndex Idx)
	leaveIntvBefore - Leave the open interval before the instruction at Idx.

SlotIndex	leaveIntvAtTop (MachineBasicBlock &MBB)
	leaveIntvAtTop - Leave the interval at the top of MBB.

void	overlapIntv (SlotIndex Start, SlotIndex End)
	overlapIntv - Indicate that all instructions in range should use the open interval if End does not have tied-def usage of the register and in this case complement interval is used.

void	finish (SmallVectorImpl< unsigned > *LRMap=nullptr)
	finish - after all the new live ranges have been created, compute the remaining live range, and rewrite instructions to use the new registers.

void	dump () const
	dump - print the current interval mapping to dbgs().

void	splitSingleBlock (const SplitAnalysis::BlockInfo &BI)
	splitSingleBlock - Split CurLI into a separate live interval around the uses in a single block.

void	splitLiveThroughBlock (unsigned MBBNum, unsigned IntvIn, SlotIndex LeaveBefore, unsigned IntvOut, SlotIndex EnterAfter)
	splitLiveThroughBlock - Split CurLI in the given block such that it enters the block in IntvIn and leaves it in IntvOut.

void	splitRegInBlock (const SplitAnalysis::BlockInfo &BI, unsigned IntvIn, SlotIndex LeaveBefore)
	splitRegInBlock - Split CurLI in the given block such that it enters the block in IntvIn and leaves it on the stack (or not at all).

void	splitRegOutBlock (const SplitAnalysis::BlockInfo &BI, unsigned IntvOut, SlotIndex EnterAfter)
	splitRegOutBlock - Split CurLI in the given block such that it enters the block on the stack (or isn't live-in at all) and leaves it in IntvOut.

Detailed Description

SplitEditor - Edit machine code and LiveIntervals for live range splitting.

Create a SplitEditor from a SplitAnalysis.
Start a new live interval with openIntv.
Mark the places where the new interval is entered using enterIntv*
Mark the ranges where the new interval is used with useIntv*
Mark the places where the interval is exited with exitIntv*.
Finish the current interval with closeIntv and repeat from 2.
Rewrite instructions with finish().

Definition at line 263 of file SplitKit.h.

Member Enumeration Documentation

◆ ComplementSpillMode

enum llvm::SplitEditor::ComplementSpillMode

ComplementSpillMode - Select how the complement live range should be created.

SplitEditor automatically creates interval 0 to contain anything that isn't added to another interval. This complement interval can get quite complicated, and it can sometimes be an advantage to allow it to overlap the other intervals. If it is going to spill anyway, no registers are wasted by keeping a value in two places at the same time.

Enumerator

SM_Partition

SM_Partition(Default) - Try to create the complement interval so it doesn't overlap any other intervals, and the original interval is partitioned.

This may require a large number of back copies and extra PHI-defs. Only segments marked with overlapIntv will be overlapping.

SM_Size

SM_Size - Overlap intervals to minimize the number of inserted COPY instructions.

Copies to the complement interval are hoisted to their common dominator, so only one COPY is required per value in the complement interval. This also means that no extra PHI-defs need to be inserted in the complement interval.

SM_Speed

SM_Speed - Overlap intervals to minimize the expected execution frequency of the inserted copies.

This is very similar to SM_Size, but the complement interval may get some extra PHI-defs.

Definition at line 281 of file SplitKit.h.

Constructor & Destructor Documentation

◆ SplitEditor()

SplitEditor::SplitEditor	(	SplitAnalysis &	SA,
		LiveIntervals &	LIS,
		VirtRegMap &	VRM,
		MachineDominatorTree &	MDT,
		MachineBlockFrequencyInfo &	MBFI,
		VirtRegAuxInfo &	VRAI
	)

Create a new SplitEditor for editing the LiveInterval analyzed by SA.

Newly created intervals will be appended to newIntervals.

Definition at line 358 of file SplitKit.cpp.

References Allocator.

Member Function Documentation

◆ currentIntv()

unsigned llvm::SplitEditor::currentIntv ( ) const

inline

currentIntv - Return the current interval index.

Definition at line 459 of file SplitKit.h.

◆ dump()

LLVM_DUMP_METHOD void SplitEditor::dump ( ) const

dump - print the current interval mapping to dbgs().

Definition at line 384 of file SplitKit.cpp.

References llvm::IntervalMap< KeyT, ValT, N, Traits >::begin(), llvm::IntervalMap< SlotIndex, unsigned >::const_iterator, llvm::dbgs(), llvm::IntervalMap< KeyT, ValT, N, Traits >::empty(), and I.

Referenced by enterIntvAtEnd(), leaveIntvAtTop(), overlapIntv(), and useIntv().

◆ enterIntvAfter()

SlotIndex SplitEditor::enterIntvAfter ( SlotIndex Idx )

enterIntvAfter - Enter the open interval after the instruction at Idx.

Return the beginning of the new live range.

Definition at line 680 of file SplitKit.cpp.

References assert(), llvm::dbgs(), llvm::VNInfo::def, llvm::LiveIntervals::getInstructionFromIndex(), llvm::LiveRangeEdit::getParent(), llvm::LiveRange::getVNInfoAt(), llvm::VNInfo::id, Idx, LLVM_DEBUG, and MI.

Referenced by splitLiveThroughBlock(), and splitRegOutBlock().

◆ enterIntvAtEnd()

SlotIndex SplitEditor::enterIntvAtEnd ( MachineBasicBlock & MBB )

enterIntvAtEnd - Enter the open interval at the end of MBB.

Use the open interval from the inserted copy to the MBB end. Return the beginning of the new live range.

Definition at line 698 of file SplitKit.cpp.

References assert(), llvm::dbgs(), llvm::VNInfo::def, dump(), End, llvm::SplitAnalysis::getLastSplitPoint(), llvm::SplitAnalysis::getLastSplitPointIter(), llvm::LiveIntervals::getMBBEndIdx(), llvm::LiveRangeEdit::getParent(), llvm::LiveRange::getVNInfoAt(), llvm::VNInfo::id, llvm::IntervalMap< KeyT, ValT, N, Traits >::insert(), llvm::Last, LLVM_DEBUG, MBB, and llvm::printMBBReference().

Referenced by splitLiveThroughBlock().

◆ enterIntvBefore()

SlotIndex SplitEditor::enterIntvBefore ( SlotIndex Idx )

enterIntvBefore - Enter the open interval before the instruction at Idx.

If the parent interval is not live before Idx, a COPY is not inserted. Return the beginning of the new live range.

Definition at line 663 of file SplitKit.cpp.

References assert(), llvm::dbgs(), llvm::VNInfo::def, llvm::LiveIntervals::getInstructionFromIndex(), llvm::LiveRangeEdit::getParent(), llvm::LiveRange::getVNInfoAt(), llvm::VNInfo::id, Idx, LLVM_DEBUG, and MI.

Referenced by splitLiveThroughBlock(), splitRegInBlock(), splitRegOutBlock(), and splitSingleBlock().

◆ finish()

void SplitEditor::finish ( SmallVectorImpl< unsigned > * LRMap = nullptr )

finish - after all the new live ranges have been created, compute the remaining live range, and rewrite instructions to use the new registers.

Parameters

LRMap When not null, this vector will map each live range in Edit back to the indices returned by openIntv. There may be extra indices created by dead code elimination.

Definition at line 1502 of file SplitKit.cpp.

References assert(), llvm::SmallVectorImpl< T >::assign(), llvm::VNInfo::def, llvm::LiveIntervals::getInterval(), llvm::VirtRegMap::getMachineFunction(), llvm::VirtRegMap::getOriginal(), llvm::VNInfo::isUnused(), llvm::IntervalMap< KeyT, ValT, N, Traits >::lookup(), llvm::LiveInterval::removeEmptySubRanges(), llvm::LiveRange::RenumberValues(), llvm::SmallVectorImpl< T >::resize(), llvm::VirtRegMap::setIsSplitFromReg(), llvm::SmallVectorBase< Size_T >::size(), SM_Partition, SM_Size, SM_Speed, and llvm::LiveIntervals::splitSeparateComponents().

◆ leaveIntvAfter()

SlotIndex SplitEditor::leaveIntvAfter ( SlotIndex Idx )

leaveIntvAfter - Leave the open interval after the instruction at Idx.

Return the end of the live range.

Definition at line 746 of file SplitKit.cpp.

References assert(), llvm::dbgs(), llvm::VNInfo::def, llvm::LiveIntervals::getInstructionFromIndex(), llvm::SlotIndex::getNextSlot(), llvm::LiveRangeEdit::getParent(), llvm::LiveRangeEdit::getReg(), llvm::LiveRange::getVNInfoAt(), llvm::VNInfo::id, Idx, llvm::SlotIndex::isSameInstr(), LLVM_DEBUG, and MI.

Referenced by splitRegInBlock(), and splitSingleBlock().

◆ leaveIntvAtTop()

SlotIndex SplitEditor::leaveIntvAtTop ( MachineBasicBlock & MBB )

leaveIntvAtTop - Leave the interval at the top of MBB.

Add liveness from the MBB top to the copy. Return the end of the live range.

Definition at line 796 of file SplitKit.cpp.

References assert(), llvm::MachineBasicBlock::begin(), llvm::dbgs(), llvm::VNInfo::def, dump(), llvm::LiveRangeEdit::get(), llvm::LiveIntervals::getInterval(), llvm::LiveIntervals::getMBBStartIdx(), llvm::LiveRangeEdit::getParent(), llvm::LiveRange::getVNInfoAt(), llvm::IntervalMap< KeyT, ValT, N, Traits >::insert(), LLVM_DEBUG, MBB, llvm::printMBBReference(), llvm::LiveInterval::reg(), and llvm::MachineBasicBlock::SkipPHIsLabelsAndDebug().

Referenced by splitLiveThroughBlock().

◆ leaveIntvBefore()

SlotIndex SplitEditor::leaveIntvBefore ( SlotIndex Idx )

leaveIntvBefore - Leave the open interval before the instruction at Idx.

Return the end of the live range.

Definition at line 777 of file SplitKit.cpp.

References assert(), llvm::dbgs(), llvm::VNInfo::def, llvm::LiveIntervals::getInstructionFromIndex(), llvm::LiveRangeEdit::getParent(), llvm::LiveRange::getVNInfoAt(), llvm::VNInfo::id, Idx, LLVM_DEBUG, and MI.

Referenced by splitLiveThroughBlock(), splitRegInBlock(), and splitSingleBlock().

◆ openIntv()

unsigned SplitEditor::openIntv ( )

Create a new virtual register and live interval.

Return the interval index, starting from 1. Interval index 0 is the implicit complement interval.

Definition at line 645 of file SplitKit.cpp.

References llvm::LiveRangeEdit::createEmptyInterval(), llvm::LiveRangeEdit::empty(), and llvm::LiveRangeEdit::size().

Referenced by splitRegInBlock(), splitRegOutBlock(), and splitSingleBlock().

◆ overlapIntv()

void SplitEditor::overlapIntv	(	SlotIndex	Start,
		SlotIndex	End
	)

overlapIntv - Indicate that all instructions in range should use the open interval if End does not have tied-def usage of the register and in this case complement interval is used.

Let the complement interval be live.

This doubles the register pressure, but is sometimes required to deal with register uses after the last valid split point.

The Start index should be a return value from a leaveIntv* call, and End should be in the same basic block. The parent interval must have the same value across the range.

Definition at line 823 of file SplitKit.cpp.

References assert(), llvm::dbgs(), dump(), End, llvm::LiveIntervals::getInstructionFromIndex(), llvm::LiveIntervals::getMBBFromIndex(), llvm::LiveRangeEdit::getParent(), llvm::LiveRangeEdit::getReg(), llvm::LiveRange::getVNInfoAt(), llvm::LiveRange::getVNInfoBefore(), hasTiedUseOf(), llvm::IntervalMap< KeyT, ValT, N, Traits >::insert(), LLVM_DEBUG, and MI.

Referenced by splitRegInBlock(), and splitSingleBlock().

◆ reset()

void SplitEditor::reset	(	LiveRangeEdit &	LRE,
		ComplementSpillMode	SM = `SM_Partition`
	)

reset - Prepare for a new split.

Definition at line 366 of file SplitKit.cpp.

References llvm::LiveRangeEdit::anyRematerializable(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::clear(), llvm::IntervalMap< KeyT, ValT, N, Traits >::clear(), llvm::VirtRegMap::getMachineFunction(), llvm::LiveIntervals::getSlotIndexes(), llvm::LiveIntervals::getVNInfoAllocator(), and llvm::LiveRangeCalc::reset().

◆ selectIntv()

void SplitEditor::selectIntv ( unsigned Idx )

selectIntv - Select a previously opened interval index.

Definition at line 656 of file SplitKit.cpp.

References assert(), llvm::dbgs(), Idx, LLVM_DEBUG, and llvm::size().

Referenced by splitLiveThroughBlock(), splitRegInBlock(), and splitRegOutBlock().

◆ splitLiveThroughBlock()

void SplitEditor::splitLiveThroughBlock	(	unsigned	MBBNum,
		unsigned	IntvIn,
		SlotIndex	LeaveBefore,
		unsigned	IntvOut,
		SlotIndex	EnterAfter
	)

splitLiveThroughBlock - Split CurLI in the given block such that it enters the block in IntvIn and leaves it in IntvOut.

There may be uses in the block, but they will be ignored when placing split points.

Parameters

MBBNum	Block number.
IntvIn	Interval index entering the block.
LeaveBefore	When set, leave IntvIn before this point.
IntvOut	Interval index leaving the block.
EnterAfter	When set, enter IntvOut after this point.

Definition at line 1633 of file SplitKit.cpp.

References assert(), llvm::dbgs(), enterIntvAfter(), enterIntvAtEnd(), enterIntvBefore(), llvm::SlotIndex::getBaseIndex(), llvm::MachineFunction::getBlockNumbered(), llvm::SlotIndex::getBoundaryIndex(), llvm::SplitAnalysis::getLastSplitPoint(), llvm::VirtRegMap::getMachineFunction(), llvm::SlotIndexes::getMBBRange(), llvm::LiveIntervals::getSlotIndexes(), Idx, leaveIntvAtTop(), leaveIntvBefore(), LLVM_DEBUG, MBB, selectIntv(), and useIntv().

◆ splitRegInBlock()

void SplitEditor::splitRegInBlock	(	const SplitAnalysis::BlockInfo &	BI,
		unsigned	IntvIn,
		SlotIndex	LeaveBefore
	)

splitRegInBlock - Split CurLI in the given block such that it enters the block in IntvIn and leaves it on the stack (or not at all).

Split points are placed in a way that avoids putting uses in the stack interval. This may require creating a local interval when there is interference.

Parameters

BI	Block descriptor.
IntvIn	Interval index entering the block. Not 0.
LeaveBefore	When set, leave IntvIn before this point.

Definition at line 1736 of file SplitKit.cpp.

References assert(), llvm::dbgs(), enterIntvBefore(), llvm::SplitAnalysis::BlockInfo::FirstInstr, From, llvm::SlotIndex::getBoundaryIndex(), llvm::SplitAnalysis::getLastSplitPoint(), llvm::SlotIndexes::getMBBRange(), llvm::LiveIntervals::getSlotIndexes(), Idx, llvm::SplitAnalysis::BlockInfo::LastInstr, leaveIntvAfter(), leaveIntvBefore(), llvm::SplitAnalysis::BlockInfo::LiveIn, llvm::SplitAnalysis::BlockInfo::LiveOut, LLVM_DEBUG, llvm::SplitAnalysis::BlockInfo::MBB, openIntv(), overlapIntv(), llvm::printMBBReference(), selectIntv(), and useIntv().

◆ splitRegOutBlock()

void SplitEditor::splitRegOutBlock	(	const SplitAnalysis::BlockInfo &	BI,
		unsigned	IntvOut,
		SlotIndex	EnterAfter
	)

splitRegOutBlock - Split CurLI in the given block such that it enters the block on the stack (or isn't live-in at all) and leaves it in IntvOut.

Split points are placed to avoid interference and such that the uses are not in the stack interval. This may require creating a local interval when there is interference.

Parameters

BI	Block descriptor.
IntvOut	Interval index leaving the block.
EnterAfter	When set, enter IntvOut after this point.

Definition at line 1829 of file SplitKit.cpp.

References assert(), llvm::dbgs(), enterIntvAfter(), enterIntvBefore(), llvm::SplitAnalysis::BlockInfo::FirstInstr, From, llvm::SlotIndex::getBaseIndex(), llvm::SplitAnalysis::getLastSplitPoint(), llvm::SlotIndexes::getMBBRange(), llvm::LiveIntervals::getSlotIndexes(), Idx, llvm::SplitAnalysis::BlockInfo::LastInstr, llvm::SplitAnalysis::BlockInfo::LiveIn, llvm::SplitAnalysis::BlockInfo::LiveOut, LLVM_DEBUG, llvm::SplitAnalysis::BlockInfo::MBB, openIntv(), llvm::printMBBReference(), selectIntv(), and useIntv().

◆ splitSingleBlock()

void SplitEditor::splitSingleBlock ( const SplitAnalysis::BlockInfo & BI )

splitSingleBlock - Split CurLI into a separate live interval around the uses in a single block.

This is intended to be used as part of a larger split, and doesn't call finish().

Definition at line 1607 of file SplitKit.cpp.

References enterIntvBefore(), llvm::SplitAnalysis::BlockInfo::FirstInstr, llvm::SplitAnalysis::getLastSplitPoint(), llvm::SplitAnalysis::BlockInfo::LastInstr, leaveIntvAfter(), leaveIntvBefore(), llvm::SplitAnalysis::BlockInfo::LiveOut, llvm::SplitAnalysis::BlockInfo::MBB, openIntv(), overlapIntv(), and useIntv().

◆ useIntv() [1/2]

void SplitEditor::useIntv ( const MachineBasicBlock & MBB )

useIntv - indicate that all instructions in MBB should use OpenLI.

Definition at line 735 of file SplitKit.cpp.

References llvm::LiveIntervals::getMBBEndIdx(), llvm::LiveIntervals::getMBBStartIdx(), MBB, and useIntv().

Referenced by splitLiveThroughBlock(), splitRegInBlock(), splitRegOutBlock(), splitSingleBlock(), and useIntv().

◆ useIntv() [2/2]

void SplitEditor::useIntv	(	SlotIndex	Start,
		SlotIndex	End
	)

useIntv - indicate that all instructions in range should use OpenLI.

Definition at line 739 of file SplitKit.cpp.

References assert(), llvm::dbgs(), dump(), End, llvm::IntervalMap< KeyT, ValT, N, Traits >::insert(), and LLVM_DEBUG.

The documentation for this class was generated from the following files:

lib/CodeGen/SplitKit.h
lib/CodeGen/SplitKit.cpp

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ ComplementSpillMode

Constructor & Destructor Documentation

◆ SplitEditor()

Member Function Documentation

◆ currentIntv()

◆ dump()

◆ enterIntvAfter()

◆ enterIntvAtEnd()

◆ enterIntvBefore()

◆ finish()

◆ leaveIntvAfter()

◆ leaveIntvAtTop()

◆ leaveIntvBefore()

◆ openIntv()

◆ overlapIntv()

◆ reset()

◆ selectIntv()

◆ splitLiveThroughBlock()

◆ splitRegInBlock()

◆ splitRegOutBlock()

◆ splitSingleBlock()

◆ useIntv() [1/2]

◆ useIntv() [2/2]