org.graalvm.compiler.nodes

Class PhiNode

java.lang.Object

org.graalvm.compiler.graph.Node

org.graalvm.compiler.nodes.ValueNode

org.graalvm.compiler.nodes.calc.FloatingNode

org.graalvm.compiler.nodes.PhiNode

All Implemented Interfaces:

Cloneable, Formattable, Node.ValueNumberable, CanonicalizableMarker, Canonicalizable, ValueNodeInterface

Direct Known Subclasses:

GuardPhiNode, MemoryPhiNode, ValuePhiNode

public abstract class PhiNode
extends FloatingNode
implements Canonicalizable

PhiNodes represent the merging of edges at a control flow merges ( AbstractMergeNode or LoopBeginNode). For a AbstractMergeNode, the order of the values corresponds to the order of the ends. For LoopBeginNodes, the first value corresponds to the loop's predecessor, while the rest of the values correspond to the LoopEndNodes.

Nested Class Summary

Nested classes/interfaces inherited from class org.graalvm.compiler.graph.Node

Node.ConstantNodeParameter, Node.EdgeVisitor, Node.IndirectCanonicalization, Node.InjectedNodeParameter, Node.Input, Node.NodeInsertionStackTrace, Node.NodeIntrinsic, Node.NodeIntrinsicFactory, Node.OptionalInput, Node.Successor, Node.ValueNumberable

Nested classes/interfaces inherited from interface org.graalvm.compiler.nodes.spi.Canonicalizable

Canonicalizable.Binary<T extends Node>, Canonicalizable.BinaryCommutative<T extends Node>, Canonicalizable.Ternary<T extends Node>, Canonicalizable.Unary<T extends Node>

Field Summary

Fields

Modifier and Type	Field and Description
protected AbstractMergeNode	merge
static NodeClass<PhiNode>	TYPE

Fields inherited from class org.graalvm.compiler.nodes.ValueNode

EMPTY_ARRAY, stamp

Fields inherited from class org.graalvm.compiler.graph.Node

NODE_LIST, NOT_ITERABLE, TRACK_CREATION_POSITION, WithAllEdges, WithNoEdges, WithOnlyInputEdges, WithOnlySucessorEdges

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PhiNode(NodeClass<? extends PhiNode> c, Stamp stamp, AbstractMergeNode merge)

Method Summary

Modifier and Type	Method and Description
void	addInput(ValueNode x)
NodeIterable<ValueNode>	backValues()
ValueNode	canonical(CanonicalizerTool tool) Implementations of this method can provide local optimizations like constant folding and strength reduction.
void	clearValues()
abstract ProxyNode	createProxyFor(LoopExitNode lex)
abstract PhiNode	duplicateOn(AbstractMergeNode newMerge) Create a phi of the same kind on the given merge.
ValueNode	firstValue()
void	initializeValueAt(int i, ValueNode x) Sets the value at the given index and makes sure that the values list is large enough.
boolean	isDegenerated()
boolean	isLoopPhi()
AbstractMergeNode	merge()
void	removeInput(int index)
void	setMerge(AbstractMergeNode x)
void	setValueAt(AbstractEndNode end, ValueNode x)
void	setValueAt(int i, ValueNode x)
ValueNode	singleBackValueOrThis() If all inputs (but the first one) are the same value, that value is returned, otherwise this.
ValueNode	singleValueOrThis() If all inputs are the same value, that value is returned, otherwise this.
String	toString(Verbosity verbosity) Creates a String representation for this with a given Verbosity.
ValueNode	valueAt(AbstractEndNode pred)
ValueNode	valueAt(int i) Get the instruction that produces the value associated with the i'th predecessor of the merge.
int	valueCount() Get the number of inputs to this phi (i.e.
protected String	valueDescription() String describing the kind of value this Phi merges.
abstract NodeInputList<ValueNode>	values()
boolean	verify()

Methods inherited from class org.graalvm.compiler.nodes.ValueNode

asConstant, asJavaConstant, asNode, asSerializableConstant, checkReplaceAtUsagesInvariants, getStackKind, graph, hasUsagesOtherThan, inferStamp, isAllowedUsageType, isConstant, isConstantPredicate, isDefaultConstant, isIllegalConstant, isJavaConstant, isNullConstant, isSerializableConstant, recursivelyDataFlowEqualsUpTo, setStamp, stamp, updateStamp, updateUsagesInterface

Methods inherited from class org.graalvm.compiler.graph.Node

afterClone, applyInputs, applySuccessors, assertFalse, assertTrue, cfgPredecessors, cfgSuccessors, clearInputs, clearNodeSourcePosition, clearSuccessors, copyWithInputs, copyWithInputs, dataFlowEquals, dynamicNodeSizeEstimate, estimatedNodeCycles, estimatedNodeSize, fail, formatTo, getCreationPosition, getDebug, getDebugProperties, getDebugProperties, getInsertionPosition, getNodeClass, getNodeSourcePosition, getOptions, getUsageCount, hasExactlyOneUsage, hashCode, hasMoreThanOneUsage, hasNoUsages, hasOnlyUsagesOfType, hasUsages, hasUsagesOfType, inputPositions, inputs, isAlive, isDeleted, isUnregistered, markDeleted, maybeNotifyZeroUsages, modCount, predecessor, pushInputs, removeUsage, replaceAllInputs, replaceAndDelete, replaceAtAllUsages, replaceAtMatchingUsages, replaceAtPredecessor, replaceAtUsages, replaceAtUsages, replaceAtUsages, replaceAtUsages, replaceAtUsages, replaceAtUsagesAndDelete, replaceAtUsagesAndDelete, replaceFirstInput, replaceFirstSuccessor, safeDelete, setCreationPosition, setInsertionPosition, setNodeSourcePosition, singleUsage, successorPositions, successors, toString, updateNodeSourcePosition, updatePredecessor, updateUsages, usages, valueEquals, verifyEdges, verifyInputs, verifySourcePosition, withNodeSourcePosition

Methods inherited from class java.lang.Object

clone, equals, getClass, notify, notifyAll, wait, wait, wait

Field Detail

TYPE

public static final NodeClass<PhiNode> TYPE

merge

protected AbstractMergeNode merge

Constructor Detail

PhiNode

protected PhiNode(NodeClass<? extends PhiNode> c,
                  Stamp stamp,
                  AbstractMergeNode merge)

Method Detail

values

public abstract NodeInputList<ValueNode> values()

merge

public AbstractMergeNode merge()

setMerge

public void setMerge(AbstractMergeNode x)

verify

public boolean verify()

Overrides:

verify in class Node

valueAt

public ValueNode valueAt(int i)

Get the instruction that produces the value associated with the i'th predecessor of the merge.

Parameters:

i - the index of the predecessor

Returns:

the instruction that produced the value in the i'th predecessor

initializeValueAt

public void initializeValueAt(int i,
                              ValueNode x)

Sets the value at the given index and makes sure that the values list is large enough.

Parameters:

i - the index at which to set the value

x - the new phi input value for the given location

setValueAt

public void setValueAt(int i,
                       ValueNode x)

setValueAt

public void setValueAt(AbstractEndNode end,
                       ValueNode x)

valueAt

public ValueNode valueAt(AbstractEndNode pred)

valueCount

public int valueCount()

Get the number of inputs to this phi (i.e. the number of predecessors to the merge).

Returns:

the number of inputs in this phi

clearValues

public void clearValues()

toString

public String toString(Verbosity verbosity)

Description copied from class: Node

Creates a String representation for this with a given Verbosity.

Overrides:

toString in class Node

valueDescription

protected String valueDescription()

String describing the kind of value this Phi merges. Used by PhiNode.toString(Verbosity) and dumping.

addInput

public void addInput(ValueNode x)

removeInput

public void removeInput(int index)

backValues

public NodeIterable<ValueNode> backValues()

singleValueOrThis

public ValueNode singleValueOrThis()

If all inputs are the same value, that value is returned, otherwise this. Note that null is a valid return value, since GuardPhiNodes can have null inputs.

singleBackValueOrThis

public ValueNode singleBackValueOrThis()

If all inputs (but the first one) are the same value, that value is returned, otherwise this. Note that null is a valid return value, since GuardPhiNodes can have null inputs.

canonical

public ValueNode canonical(CanonicalizerTool tool)

Description copied from interface: Canonicalizable

Implementations of this method can provide local optimizations like constant folding and strength reduction. Implementations should look at the properties and inputs of the current node and determine if there is a more optimal and always semantically correct replacement.
The return value determines the effect that the canonicalization will have:

• Returning an pre-existing node will replace the current node with the given one.
• Returning a newly created node (that was not yet added to the graph) will replace the current node with the given one, after adding it to the graph. If both the replacement and the replacee are anchored in control flow (fixed nodes), the replacement will be added to the control flow. It is invalid to replace a non-fixed node with a newly created fixed node (because its placement in the control flow cannot be determined without scheduling).
• Returning null will delete the current node and replace it with null at all usages. Note that it is not necessary to delete floating nodes that have no more usages this way - they will be deleted automatically.

Specified by:

canonical in interface Canonicalizable

Parameters:

tool - provides access to runtime interfaces like MetaAccessProvider

firstValue

public ValueNode firstValue()

isLoopPhi

public boolean isLoopPhi()

isDegenerated

public boolean isDegenerated()

Returns:

true if this node's only usages are the node itself (only possible for loops).

createProxyFor

public abstract ProxyNode createProxyFor(LoopExitNode lex)

duplicateOn

public abstract PhiNode duplicateOn(AbstractMergeNode newMerge)

Create a phi of the same kind on the given merge.

Parameters:

newMerge - the merge to use for the newly created phi