LLVM: llvm::SpillPlacement::Node Struct Reference

LLVM 20.0.0git

Node - Each edge bundle corresponds to a Hopfield node. More...

Public Types
using	LinkVector = SmallVector< std::pair< BlockFrequency, unsigned >, 4 >

Public Member Functions
bool	preferReg () const
	preferReg - Return true when this node prefers to be in a register.

bool	mustSpill () const
	mustSpill - Return True if this node is so biased that it must spill.

void	clear (BlockFrequency Threshold)
	clear - Reset per-query data, but preserve frequencies that only depend on the CFG.

void	addLink (unsigned b, BlockFrequency w)
	addLink - Add a link to bundle b with weight w.

void	addBias (BlockFrequency freq, BorderConstraint direction)
	addBias - Bias this node.

bool	update (const Node nodes[], BlockFrequency Threshold)
	update - Recompute Value from Bias and Links.

void	getDissentingNeighbors (SparseSet< unsigned > &List, const Node nodes[]) const

Public Attributes
BlockFrequency	BiasN
	BiasN - Sum of blocks that prefer a spill.

BlockFrequency	BiasP
	BiasP - Sum of blocks that prefer a register.

int	Value
	Value - Output value of this node computed from the Bias and links.

LinkVector	Links
	Links - (Weight, BundleNo) for all transparent blocks connecting to other bundles.

BlockFrequency	SumLinkWeights
	SumLinkWeights - Cached sum of the weights of all links + ThresHold.

Detailed Description

Node - Each edge bundle corresponds to a Hopfield node.

The node contains precomputed frequency data that only depends on the CFG, but Bias and Links are computed each time placeSpills is called.

The node Value is positive when the variable should be in a register. The value can change when linked nodes change, but convergence is very fast because all weights are positive.

Definition at line 72 of file SpillPlacement.cpp.

Member Typedef Documentation

◆ LinkVector

using llvm::SpillPlacement::Node::LinkVector = SmallVector<std::pair<BlockFrequency, unsigned>, 4>

Definition at line 84 of file SpillPlacement.cpp.

Member Function Documentation

◆ addBias()

void llvm::SpillPlacement::Node::addBias	(	BlockFrequency	freq,
		BorderConstraint	direction
	)

inline

addBias - Bias this node.

Definition at line 133 of file SpillPlacement.cpp.

References llvm::SpillPlacement::Node::BiasN, llvm::SpillPlacement::Node::BiasP, freq, llvm::BlockFrequency::max(), llvm::SpillPlacement::MustSpill, llvm::SpillPlacement::PrefReg, and llvm::SpillPlacement::PrefSpill.

Referenced by llvm::SpillPlacement::addConstraints(), and llvm::SpillPlacement::addPrefSpill().

◆ addLink()

void llvm::SpillPlacement::Node::addLink	(	unsigned	b,
		BlockFrequency	w
	)

inline

addLink - Add a link to bundle b with weight w.

Definition at line 118 of file SpillPlacement.cpp.

References llvm::SpillPlacement::Node::Links, llvm::SmallVectorTemplateBase< T, bool >::push_back(), and llvm::SpillPlacement::Node::SumLinkWeights.

Referenced by llvm::SpillPlacement::addLinks().

◆ clear()

void llvm::SpillPlacement::Node::clear ( BlockFrequency Threshold )

inline

clear - Reset per-query data, but preserve frequencies that only depend on the CFG.

Definition at line 109 of file SpillPlacement.cpp.

References llvm::SpillPlacement::Node::BiasN, llvm::SpillPlacement::Node::BiasP, llvm::SmallVectorImpl< T >::clear(), llvm::SpillPlacement::Node::Links, and llvm::SpillPlacement::Node::SumLinkWeights.

◆ getDissentingNeighbors()

void llvm::SpillPlacement::Node::getDissentingNeighbors	(	SparseSet< unsigned > &	List,
		const Node	nodes[]
	)		const

inline

Definition at line 180 of file SpillPlacement.cpp.

References llvm::SpillPlacement::Node::Links, llvm::List, and nodes.

◆ mustSpill()

bool llvm::SpillPlacement::Node::mustSpill ( ) const

inline

mustSpill - Return True if this node is so biased that it must spill.

Definition at line 100 of file SpillPlacement.cpp.

References llvm::SpillPlacement::Node::BiasN, llvm::SpillPlacement::Node::BiasP, and llvm::SpillPlacement::Node::SumLinkWeights.

◆ preferReg()

bool llvm::SpillPlacement::Node::preferReg ( ) const

inline

preferReg - Return true when this node prefers to be in a register.

Definition at line 94 of file SpillPlacement.cpp.

Referenced by llvm::SpillPlacement::Node::update().

◆ update()

bool llvm::SpillPlacement::Node::update	(	const Node	nodes[],
		BlockFrequency	Threshold
	)

inline

update - Recompute Value from Bias and Links.

Return true when node preference changes.

Definition at line 151 of file SpillPlacement.cpp.

References Before, llvm::SpillPlacement::Node::BiasN, llvm::SpillPlacement::Node::BiasP, llvm::SpillPlacement::Node::Links, nodes, and llvm::SpillPlacement::Node::preferReg().

Member Data Documentation

◆ BiasN

BlockFrequency llvm::SpillPlacement::Node::BiasN

BiasN - Sum of blocks that prefer a spill.

Definition at line 74 of file SpillPlacement.cpp.

Referenced by llvm::SpillPlacement::Node::addBias(), llvm::SpillPlacement::Node::clear(), llvm::SpillPlacement::Node::mustSpill(), and llvm::SpillPlacement::Node::update().

◆ BiasP

BlockFrequency llvm::SpillPlacement::Node::BiasP

BiasP - Sum of blocks that prefer a register.

Definition at line 77 of file SpillPlacement.cpp.

Referenced by llvm::SpillPlacement::Node::addBias(), llvm::SpillPlacement::Node::clear(), llvm::SpillPlacement::Node::mustSpill(), and llvm::SpillPlacement::Node::update().

◆ Links

LinkVector llvm::SpillPlacement::Node::Links

Links - (Weight, BundleNo) for all transparent blocks connecting to other bundles.

The weights are all positive block frequencies.

Definition at line 88 of file SpillPlacement.cpp.

Referenced by llvm::SpillPlacement::Node::addLink(), llvm::SpillPlacement::Node::clear(), llvm::SpillPlacement::Node::getDissentingNeighbors(), and llvm::SpillPlacement::Node::update().

◆ SumLinkWeights

BlockFrequency llvm::SpillPlacement::Node::SumLinkWeights

SumLinkWeights - Cached sum of the weights of all links + ThresHold.

Definition at line 91 of file SpillPlacement.cpp.

Referenced by llvm::SpillPlacement::Node::addLink(), llvm::SpillPlacement::Node::clear(), and llvm::SpillPlacement::Node::mustSpill().

◆ Value

int llvm::SpillPlacement::Node::Value

Value - Output value of this node computed from the Bias and links.

This is always on of the values {-1, 0, 1}. A positive number means the variable should go in a register through this bundle.

Definition at line 82 of file SpillPlacement.cpp.

The documentation for this struct was generated from the following file:

lib/CodeGen/SpillPlacement.cpp