LLVM  6.0.0svn
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llvm::SCEVAddRecExpr Class Reference

This node represents a polynomial recurrence on the trip count of the specified loop. More...

#include "llvm/Analysis/ScalarEvolutionExpressions.h"

Inheritance diagram for llvm::SCEVAddRecExpr:
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Collaboration diagram for llvm::SCEVAddRecExpr:
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Public Member Functions

const SCEVgetStart () const
 
const LoopgetLoop () const
 
const SCEVgetStepRecurrence (ScalarEvolution &SE) const
 Constructs and returns the recurrence indicating how much this expression steps by. More...
 
bool isAffine () const
 Return true if this represents an expression A + B*x where A and B are loop invariant values. More...
 
bool isQuadratic () const
 Return true if this represents an expression A + B*x + C*x^2 where A, B and C are loop invariant values. More...
 
void setNoWrapFlags (NoWrapFlags Flags)
 Set flags for a recurrence without clearing any previously set flags. More...
 
const SCEVevaluateAtIteration (const SCEV *It, ScalarEvolution &SE) const
 Return the value of this chain of recurrences at the specified iteration number. More...
 
const SCEVgetNumIterationsInRange (const ConstantRange &Range, ScalarEvolution &SE) const
 Return the number of iterations of this loop that produce values in the specified constant range. More...
 
const SCEVAddRecExprgetPostIncExpr (ScalarEvolution &SE) const
 Return an expression representing the value of this expression one iteration of the loop ahead. More...
 
- Public Member Functions inherited from llvm::SCEVNAryExpr
size_t getNumOperands () const
 
const SCEVgetOperand (unsigned i) const
 
op_iterator op_begin () const
 
op_iterator op_end () const
 
op_range operands () const
 
TypegetType () const
 
NoWrapFlags getNoWrapFlags (NoWrapFlags Mask=NoWrapMask) const
 
bool hasNoUnsignedWrap () const
 
bool hasNoSignedWrap () const
 
bool hasNoSelfWrap () const
 
- Public Member Functions inherited from llvm::SCEV
 SCEV (const FoldingSetNodeIDRef ID, unsigned SCEVTy)
 
 SCEV (const SCEV &)=delete
 
SCEVoperator= (const SCEV &)=delete
 
unsigned getSCEVType () const
 
TypegetType () const
 Return the LLVM type of this SCEV expression. More...
 
bool isZero () const
 Return true if the expression is a constant zero. More...
 
bool isOne () const
 Return true if the expression is a constant one. More...
 
bool isAllOnesValue () const
 Return true if the expression is a constant all-ones value. More...
 
bool isNonConstantNegative () const
 Return true if the specified scev is negated, but not a constant. More...
 
void print (raw_ostream &OS) const
 Print out the internal representation of this scalar to the specified stream. More...
 
void dump () const
 This method is used for debugging. More...
 
- Public Member Functions inherited from llvm::FoldingSetBase::Node
 Node ()
 
void * getNextInBucket () const
 
void SetNextInBucket (void *N)
 

Static Public Member Functions

static bool classof (const SCEV *S)
 Methods for support type inquiry through isa, cast, and dyn_cast: More...
 
- Static Public Member Functions inherited from llvm::SCEVNAryExpr
static bool classof (const SCEV *S)
 Methods for support type inquiry through isa, cast, and dyn_cast: More...
 

Friends

class ScalarEvolution
 

Additional Inherited Members

- Public Types inherited from llvm::SCEVNAryExpr
using op_iterator = const SCEV *const *
 
using op_range = iterator_range< op_iterator >
 
- Public Types inherited from llvm::SCEV
enum  NoWrapFlags {
  FlagAnyWrap = 0, FlagNW = (1 << 0), FlagNUW = (1 << 1), FlagNSW = (1 << 2),
  NoWrapMask = (1 << 3) - 1
}
 NoWrapFlags are bitfield indices into SubclassData. More...
 
- Protected Member Functions inherited from llvm::SCEVNAryExpr
 SCEVNAryExpr (const FoldingSetNodeIDRef ID, enum SCEVTypes T, const SCEV *const *O, size_t N)
 
- Protected Attributes inherited from llvm::SCEVNAryExpr
const SCEV *constOperands
 
size_t NumOperands
 
- Protected Attributes inherited from llvm::SCEV
unsigned short SubclassData = 0
 This field is initialized to zero and may be used in subclasses to store miscellaneous information. More...
 

Detailed Description

This node represents a polynomial recurrence on the trip count of the specified loop.

This is the primary focus of the ScalarEvolution framework; all the other SCEV subclasses are mostly just supporting infrastructure to allow SCEVAddRecExpr expressions to be created and analyzed.

All operands of an AddRec are required to be loop invariant.

Definition at line 290 of file ScalarEvolutionExpressions.h.

Member Function Documentation

◆ classof()

static bool llvm::SCEVAddRecExpr::classof ( const SCEV S)
inlinestatic

Methods for support type inquiry through isa, cast, and dyn_cast:

Definition at line 358 of file ScalarEvolutionExpressions.h.

References llvm::SCEV::getSCEVType(), and llvm::scAddRecExpr.

◆ evaluateAtIteration()

const SCEV * SCEVAddRecExpr::evaluateAtIteration ( const SCEV It,
ScalarEvolution SE 
) const

Return the value of this chain of recurrences at the specified iteration number.

We can evaluate this recurrence by multiplying each element in the chain by the binomial coefficient corresponding to it. In other words, we can evaluate {A,+,B,+,C,+,D} as:

A*BC(It, 0) + B*BC(It, 1) + C*BC(It, 2) + D*BC(It, 3)

where BC(It, k) stands for binomial coefficient.

Definition at line 1195 of file ScalarEvolution.cpp.

References BinomialCoefficient(), llvm::ScalarEvolution::getAddExpr(), llvm::ScalarEvolution::getMulExpr(), llvm::SCEVCastExpr::getOperand(), and llvm::SCEVCastExpr::getType().

Referenced by EvaluateConstantChrecAtConstant(), llvm::RuntimePointerChecking::insert(), isIgnorableInst(), SolveQuadraticEquation(), and llvm::SCEVLoopAddRecRewriter::visitAddRecExpr().

◆ getLoop()

const Loop* llvm::SCEVAddRecExpr::getLoop ( ) const
inline

◆ getNumIterationsInRange()

const SCEV * SCEVAddRecExpr::getNumIterationsInRange ( const ConstantRange Range,
ScalarEvolution SE 
) const

◆ getPostIncExpr()

const SCEVAddRecExpr* llvm::SCEVAddRecExpr::getPostIncExpr ( ScalarEvolution SE) const
inline

Return an expression representing the value of this expression one iteration of the loop ahead.

Definition at line 353 of file ScalarEvolutionExpressions.h.

References llvm::ScalarEvolution::getAddExpr().

Referenced by llvm::ScalarEvolution::isKnownPredicate().

◆ getStart()

const SCEV* llvm::SCEVAddRecExpr::getStart ( ) const
inline

◆ getStepRecurrence()

const SCEV* llvm::SCEVAddRecExpr::getStepRecurrence ( ScalarEvolution SE) const
inline

◆ isAffine()

bool llvm::SCEVAddRecExpr::isAffine ( ) const
inline

◆ isQuadratic()

bool llvm::SCEVAddRecExpr::isQuadratic ( ) const
inline

Return true if this represents an expression A + B*x + C*x^2 where A, B and C are loop invariant values.

This corresponds to an addrec of the form {L,+,M,+,N}

Definition at line 325 of file ScalarEvolutionExpressions.h.

Referenced by SolveQuadraticEquation().

◆ setNoWrapFlags()

void llvm::SCEVAddRecExpr::setNoWrapFlags ( NoWrapFlags  Flags)
inline

Set flags for a recurrence without clearing any previously set flags.

For AddRec, either NUW or NSW implies NW. Keep track of this fact here to make it easier to propagate flags.

Definition at line 332 of file ScalarEvolutionExpressions.h.

References llvm::SCEV::FlagNSW, llvm::SCEV::FlagNUW, llvm::SCEV::FlagNW, llvm::ScalarEvolution::setFlags(), and llvm::SCEV::SubclassData.

Referenced by llvm::ScalarEvolution::getAddRecExpr().

Friends And Related Function Documentation

◆ ScalarEvolution

friend class ScalarEvolution
friend

Definition at line 291 of file ScalarEvolutionExpressions.h.


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