scale.score.expr
Class DivisionExpr

java.lang.Object
  scale.common.Root
      scale.score.Note
          scale.score.expr.Expr
              scale.score.expr.BinaryExpr
                  scale.score.expr.DivisionExpr

All Implemented Interfaces:

AnnotationInterface, DisplayNode

public class DivisionExpr
extends BinaryExpr

This class represents the division operation.

$Id: DivisionExpr.java,v 1.44 2007-10-04 19:58:29 burrill Exp $

Copyright 2008 by the Scale Compiler Group,
Department of Computer Science
University of Massachusetts,
Amherst MA. 01003, USA
All Rights Reserved.

Field Summary

Fields inherited from class scale.score.expr.Expr

fpReorder, SE_DOMAIN, SE_NONE, SE_OVERFLOW, SE_STATE

Constructor Summary

DivisionExpr(Type t, Expr e1, Expr e2)

Method Summary

Expr	copy() Perform a deep copy of the expression tree.
static Expr	create(Type type, Expr la, Expr ra) This method of creating a DivisionExpr instance will return a reduced expression if possible.
int	executionCostEstimate() Return a relative cost estimate for executing the expression.
protected AffineExpr	getAffineRepresentation(HashMap<Expr,AffineExpr> affines, LoopHeaderChord thisLoop) Return the affine representation for this expression.
Literal	getConstantValue() Return the constant value of the expression.
Literal	getConstantValue(HashMap<Expr,Literal> cvMap) Return the constant value of the expression.
java.lang.String	getDisplayLabel() Return a String suitable for labeling this node in a graphical display.
boolean	isLeftDistributive() Return true if the binary operation α is left distributive over β: (a β b) α c ≡ (a α c) β (b α c).
boolean	isSimpleExpr() Return true if this is a simple expression.
boolean	mayGenerateCall() Return true if this expression may result in the generation of a call to a subroutine.
Expr	reduce() Return a simplied equivalent expression.
int	sideEffects() Return an indication of the side effects execution of this expression may cause.
void	visit(Predicate p) Process a node by calling its associated routine.

Methods inherited from class scale.score.expr.BinaryExpr

associativeSwapOperands, containsDeclaration, dependsOnDeclaration, equivalent, getAliasAnnote, getDeclList, getExprList, getLeftArg, getLoadExprList, getOperand, getOperandArray, getRightArg, isAssociative, isCommutative, isRightDistributive, loopClean, numOperands, optimizationCandidate, pushOperands, recordRefs, removeRefs, removeUseDef, replaceDecl, setLeftArg, setOperand, setRightArg, swapOperands, unlinkExpression, validate

Methods inherited from class scale.score.expr.Expr

addCast, addCast, canonical, changeInDataEdge, conditionalCopy, conditionalUnlinkExpression, deleteOutDataEdge, executionOrder, executionOrdinal, findCriticalChord, findLinearCoefficient, findSubscriptExpr, getAffineExpr, getCall, getCoreType, getCriticalChord, getDefExpr, getDisplayColorHint, getDisplayShapeHint, getDualExpr, getInDataEdge, getInDataEdgeArray, getLoopHeader, getLow, getLValue, getOutDataEdge, getPointedToCore, getReference, getReuseLevel, getRValue, getType, getUseDef, hasTrueFalseResult, isCast, isDefined, isDefined, isLiteralExpr, isLoopInvariant, isMatchExpr, isMemoryDef, isMemRefExpr, isScalar, numInDataEdges, removeDualExprs, setCrossloopReuse, setOutDataEdge, setSpatialReuse, setStep, setTemporalReuse, setType, setUseDef, toStringSpecial, validLValue

Methods inherited from class scale.score.Note

getChord, getEssentialUse, setAnnotationLevel, setReportLevel, toString

Methods inherited from class scale.common.Root

addAnnotation, allAnnotations, allMatchingAnnotations, getAnnotation, getDisplayName, getDisplayString, getNodeCount, getNodeID, hasAnnotation, hasEqualAnnotation, hashCode, removeAnnotation, removeAnnotations, toStringAnnotations, toStringClass, trace, trace, trace

Methods inherited from class java.lang.Object

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

Constructor Detail

DivisionExpr

public DivisionExpr(Type t,
                    Expr e1,
                    Expr e2)

Method Detail

create

public static Expr create(Type type,
                          Expr la,
                          Expr ra)

This method of creating a DivisionExpr instance will return a reduced expression if possible.

copy

public Expr copy()

Description copied from class: Expr

Perform a deep copy of the expression tree. By deep copy, we mean that copies are made of the expression tree.

Specified by:

copy in class Expr

Returns:

a copy of this expression

sideEffects

public int sideEffects()

Return an indication of the side effects execution of this expression may cause.

Overrides:

sideEffects in class BinaryExpr

See Also:

Expr.SE_NONE

visit

public void visit(Predicate p)

Description copied from class: Note

Process a node by calling its associated routine. See the "visitor" design pattern in Design Patterns: Elements of Reusable Object-Oriented Software by E. Gamma, et al, Addison Wesley, ISBN 0-201-63361-2.

Each class has a visit(Predicate p) method. For example, in class ABC:

   public void visit(Predicate p)
   {
     p.visitABC(this);
   }
 

and the class that implements Predicate has a method

   public void visitABC(Note n)
   {
     ABC a = (ABC) n;
     ...
   }
 

Thus, the class that implements Predicate can call

   n.visit(this);
 

where n is a Note sub-class without determining which specific sub-class n is. The visit pattern basically avoids implementing a large switch statement or defining different methods in each class for some purpose.

Specified by:

visit in class Note

See Also:

Predicate

getDisplayLabel

public java.lang.String getDisplayLabel()

Description copied from class: Expr

Return a String suitable for labeling this node in a graphical display. This method should be over-ridden as it simplay returns the class name.

Specified by:

getDisplayLabel in interface DisplayNode

Overrides:

getDisplayLabel in class Expr

getAffineRepresentation

protected AffineExpr getAffineRepresentation(HashMap<Expr,AffineExpr> affines,
                                             LoopHeaderChord thisLoop)

Description copied from class: Expr

Return the affine representation for this expression. This method should be called only from the getAffineExpr() method. This method never returns null.

Overrides:

getAffineRepresentation in class Expr

Parameters:

affines - is a mapping from an expression to its representation and is used to avoid combinatorial explosion through use-def links

thisLoop - the loop for which this expression may be affine

See Also:

AffineExpr, AffineExpr.notAffine

getConstantValue

public Literal getConstantValue(HashMap<Expr,Literal> cvMap)

Return the constant value of the expression. Follow use-def links.

Overrides:

getConstantValue in class Expr

See Also:

Lattice

getConstantValue

public Literal getConstantValue()

Return the constant value of the expression. Do not follow use-def links.

Overrides:

getConstantValue in class Expr

See Also:

Lattice

isLeftDistributive

public boolean isLeftDistributive()

Description copied from class: BinaryExpr

Return true if the binary operation α is left distributive over β: (a β b) α c ≡ (a α c) β (b α c).

Overrides:

isLeftDistributive in class BinaryExpr

executionCostEstimate

public int executionCostEstimate()

Return a relative cost estimate for executing the expression.

Overrides:

executionCostEstimate in class BinaryExpr

isSimpleExpr

public boolean isSimpleExpr()

Return true if this is a simple expression. A simple expression consists solely of local scalar variables, constants, and numeric operations such as add, subtract, multiply, and divide.

Overrides:

isSimpleExpr in class Expr

mayGenerateCall

public boolean mayGenerateCall()

Return true if this expression may result in the generation of a call to a subroutine.

Overrides:

mayGenerateCall in class Expr

reduce

public Expr reduce()

Return a simplied equivalent expression. If both the divisor and the quotient are constants, we replace this expression with a constant. If just the divisor is a floating point constant and floating point re-ordering is allowed, we replace this expression with a multiply. This method may modify the original expression. This is used in the lowering of subscript expressions.

Overrides:

reduce in class Expr

See Also:

SubscriptExpr.lower()