llvm::MonotonicDescriptor Class Reference

A struct for saving information about monotonic variables. More...

#include "llvm/Analysis/IVDescriptors.h"

Public Member Functions
	MonotonicDescriptor ()=default
PHINode *	getHeaderPHI () const
	Returns the header PHI described by this descriptor.
PHINode *	getBackedgePHI () const
	Returns the backedge PHI that selects between StepInst and the HeaderPHI.
Instruction *	getStepInst () const
	Returns the instruction that updates the value of the monotonic PHI.
const SCEV *	getStartSCEV () const
	Returns a SCEV expression for the initial value of the monotonic PHI.
const SCEV *	getStepSCEV () const
	Returns a SCEV expression for the step of the monotonic PHI.
unsigned	getSCEVNoWrapFlags () const
	Returns the SCEV no-wrap flags that apply to StepInst.

Static Public Member Functions
static LLVM_ABI bool	isMonotonicPHI (PHINode *PN, const Loop *L, MonotonicDescriptor &Desc, ScalarEvolution &SE)
	Returns true if PN is a monotonic variable in the loop L.

Detailed Description

A struct for saving information about monotonic variables.

Monotonic variable can be considered as a "conditional" induction variable: its update happens only on loop iterations for which a certain predicate is satisfied. The step of the monotonic variable must be loop-invariant.

Definition at line 489 of file IVDescriptors.h.

Constructor & Destructor Documentation

MonotonicDescriptor()

llvm::MonotonicDescriptor::MonotonicDescriptor ( )

default

References LLVM_ABI, and MonotonicDescriptor().

Referenced by isMonotonicPHI(), and MonotonicDescriptor().

Member Function Documentation

getBackedgePHI()

PHINode * llvm::MonotonicDescriptor::getBackedgePHI ( ) const

inline

Returns the backedge PHI that selects between StepInst and the HeaderPHI.

Definition at line 504 of file IVDescriptors.h.

getHeaderPHI()

PHINode * llvm::MonotonicDescriptor::getHeaderPHI ( ) const

inline

Returns the header PHI described by this descriptor.

Definition at line 501 of file IVDescriptors.h.

getSCEVNoWrapFlags()

unsigned llvm::MonotonicDescriptor::getSCEVNoWrapFlags ( ) const

inline

Returns the SCEV no-wrap flags that apply to StepInst.

Definition at line 518 of file IVDescriptors.h.

getStartSCEV()

const SCEV * llvm::MonotonicDescriptor::getStartSCEV ( ) const

inline

Returns a SCEV expression for the initial value of the monotonic PHI.

Definition at line 510 of file IVDescriptors.h.

getStepInst()

Instruction * llvm::MonotonicDescriptor::getStepInst ( ) const

inline

Returns the instruction that updates the value of the monotonic PHI.

Definition at line 507 of file IVDescriptors.h.

getStepSCEV()

const SCEV * llvm::MonotonicDescriptor::getStepSCEV ( ) const

inline

Returns a SCEV expression for the step of the monotonic PHI.

This is the value the monotonic PHI increments by on loop iterations where the predicate is satisfied.

Definition at line 515 of file IVDescriptors.h.

isMonotonicPHI()

bool MonotonicDescriptor::isMonotonicPHI ( PHINode * PN, const Loop * L, MonotonicDescriptor & Desc, ScalarEvolution & SE )

static

Returns true if PN is a monotonic variable in the loop L.

If PN is monotonic, the monotonic descriptor D will contain the data describing the PHI.

Definition at line 1712 of file IVDescriptors.cpp.

References llvm::cast(), llvm::dbgs(), llvm::dyn_cast(), llvm::find_singleton(), llvm::SCEV::FlagAnyWrap, llvm::SCEV::FlagNSW, llvm::SCEV::FlagNUW, GEP, llvm::ScalarEvolution::getEffectiveSCEVType(), llvm::ScalarEvolution::getSCEV(), llvm::ScalarEvolution::getTruncateOrSignExtend(), llvm::SCEV::getType(), llvm::Value::getType(), llvm::Value::hasOneUse(), llvm::Type::isIntOrPtrTy(), llvm::ScalarEvolution::isKnownNonNegative(), llvm::Type::isPointerTy(), LLVM_DEBUG, llvm::PatternMatch::m_c_Add(), llvm::PatternMatch::m_PtrAdd(), llvm::PatternMatch::m_Specific(), llvm::PatternMatch::m_Value(), llvm::PatternMatch::match(), MonotonicDescriptor(), llvm::ScalarEvolution::setFlags(), llvm::to_underlying(), and llvm::Value::users().

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

• include/llvm/Analysis/IVDescriptors.h
• lib/Analysis/IVDescriptors.cpp