This class represents an assumption made on an AddRec expression. More...

#include "llvm/Analysis/ScalarEvolution.h"

Inheritance diagram for llvm::SCEVWrapPredicate:

Public Types
enum	IncrementWrapFlags { IncrementAnyWrap = 0 , IncrementNUSW = (1 << 0) , IncrementNSSW = (1 << 1) , IncrementNoWrapMask = (1 << 2) - 1 }
	Similar to SCEV::NoWrapFlags, but with slightly different semantics for FlagNUSW. More...
Public Types inherited from llvm::SCEVPredicate
enum	SCEVPredicateKind { P_Union , P_Compare , P_Wrap }

Public Member Functions
	SCEVWrapPredicate (const FoldingSetNodeIDRef ID, const SCEVAddRecExpr *AR, IncrementWrapFlags Flags)
IncrementWrapFlags	getFlags () const
	Returns the set assumed no overflow flags.
const SCEVAddRecExpr *	getExpr () const
	Implementation of the SCEVPredicate interface.
bool	implies (const SCEVPredicate *N, ScalarEvolution &SE) const override
	Returns true if this predicate implies `N`.
void	print (raw_ostream &OS, unsigned Depth=0) const override
	Prints a textual representation of this predicate with an indentation of `Depth`.
bool	isAlwaysTrue () const override
	Returns true if the predicate is always true.
Public Member Functions inherited from llvm::SCEVPredicate
LLVM_ABI	SCEVPredicate (const FoldingSetNodeIDRef ID, SCEVPredicateKind Kind)
	SCEV predicates.
SCEVPredicateKind	getKind () const
virtual unsigned	getComplexity () const
	Returns the estimated complexity of this predicate.
Public Member Functions inherited from llvm::FoldingSetBase::Node
	Node ()=default
void *	getNextInBucket () const
void	SetNextInBucket (void *N)

Static Public Member Functions
static SCEVWrapPredicate::IncrementWrapFlags	clearFlags (SCEVWrapPredicate::IncrementWrapFlags Flags, SCEVWrapPredicate::IncrementWrapFlags OffFlags)
	Convenient IncrementWrapFlags manipulation methods.
static SCEVWrapPredicate::IncrementWrapFlags	maskFlags (SCEVWrapPredicate::IncrementWrapFlags Flags, int Mask)
static SCEVWrapPredicate::IncrementWrapFlags	setFlags (SCEVWrapPredicate::IncrementWrapFlags Flags, SCEVWrapPredicate::IncrementWrapFlags OnFlags)
static SCEVWrapPredicate::IncrementWrapFlags	getImpliedFlags (const SCEVAddRecExpr *AR, ScalarEvolution &SE)
	Returns the set of SCEVWrapPredicate no wrap flags implied by a SCEVAddRecExpr.
static bool	classof (const SCEVPredicate *P)
	Methods for support type inquiry through isa, cast, and dyn_cast:

Additional Inherited Members
Protected Member Functions inherited from llvm::SCEVPredicate
	~SCEVPredicate ()=default
	SCEVPredicate (const SCEVPredicate &)=default
SCEVPredicate &	operator= (const SCEVPredicate &)=default
Protected Attributes inherited from llvm::SCEVPredicate
SCEVPredicateKind	Kind

Detailed Description

This class represents an assumption made on an AddRec expression.

Given an affine AddRec expression {a,+,b}, we assume that it has the nssw or nusw flags (defined below) in the first X iterations of the loop, where X is a SCEV expression returned by getPredicatedBackedgeTakenCount).

Note that this does not imply that X is equal to the backedge taken count. This means that if we have a nusw predicate for i32 {0,+,1} with a predicated backedge taken count of X, we only guarantee that {0,+,1} has nusw in the first X iterations. {0,+,1} may still wrap in the loop if we have more than X iterations.

Definition at line 318 of file ScalarEvolution.h.

Member Enumeration Documentation

◆ IncrementWrapFlags

enum llvm::SCEVWrapPredicate::IncrementWrapFlags

Similar to SCEV::NoWrapFlags, but with slightly different semantics for FlagNUSW.

The increment is considered to be signed, and a + b (where b is the increment) is considered to wrap if: zext(a + b) != zext(a) + sext(b)

If Signed is a function that takes an n-bit tuple and maps to the integer domain as the tuples value interpreted as twos complement, and Unsigned a function that takes an n-bit tuple and maps to the integer domain as the base two value of input tuple, then a + b has IncrementNUSW iff:

0 <= Unsigned(a) + Signed(b) < 2^n

The IncrementNSSW flag has identical semantics with SCEV::FlagNSW.

Note that the IncrementNUSW flag is not commutative: if base + inc has IncrementNUSW, then inc + base doesn't neccessarily have this property. The reason for this is that this is used for sign/zero extending affine AddRec SCEV expressions when a SCEVWrapPredicate is assumed. A {base,+,inc} expression is already non-commutative with regards to base and inc, since it is interpreted as: (((base + inc) + inc) + inc) ...

Enumerator
IncrementAnyWrap
IncrementNUSW
IncrementNSSW
IncrementNoWrapMask

Definition at line 342 of file ScalarEvolution.h.

Constructor & Destructor Documentation

◆ SCEVWrapPredicate()

SCEVWrapPredicate::SCEVWrapPredicate	(	const FoldingSetNodeIDRef	ID,
		const SCEVAddRecExpr *	AR,
		IncrementWrapFlags	Flags )

explicit

Definition at line 15081 of file ScalarEvolution.cpp.

References llvm::SCEVPredicate::P_Wrap, and llvm::SCEVPredicate::SCEVPredicate().

Member Function Documentation

◆ classof()

bool llvm::SCEVWrapPredicate::classof ( const SCEVPredicate * P )

inlinestatic

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

Definition at line 402 of file ScalarEvolution.h.

References P, llvm::SCEVPredicate::P_Wrap, and llvm::SCEVPredicate::SCEVPredicate().

◆ clearFlags()

SCEVWrapPredicate::IncrementWrapFlags llvm::SCEVWrapPredicate::clearFlags	(	SCEVWrapPredicate::IncrementWrapFlags	Flags,
		SCEVWrapPredicate::IncrementWrapFlags	OffFlags )

inlinestaticnodiscard

Convenient IncrementWrapFlags manipulation methods.

Definition at line 352 of file ScalarEvolution.h.

References assert(), and IncrementNoWrapMask.

Referenced by llvm::PredicatedScalarEvolution::hasNoOverflow(), isAlwaysTrue(), and llvm::PredicatedScalarEvolution::setNoOverflow().

◆ getExpr()

const SCEVAddRecExpr * SCEVWrapPredicate::getExpr ( ) const

Implementation of the SCEVPredicate interface.

Definition at line 15086 of file ScalarEvolution.cpp.

Referenced by print().

◆ getFlags()

IncrementWrapFlags llvm::SCEVWrapPredicate::getFlags ( ) const

inline

Returns the set assumed no overflow flags.

Definition at line 393 of file ScalarEvolution.h.

Referenced by print().

◆ getImpliedFlags()

SCEVWrapPredicate::IncrementWrapFlags SCEVWrapPredicate::getImpliedFlags	(	const SCEVAddRecExpr *	AR,
		ScalarEvolution &	SE )

staticnodiscard

Returns the set of SCEVWrapPredicate no wrap flags implied by a SCEVAddRecExpr.

Definition at line 15151 of file ScalarEvolution.cpp.

References llvm::dyn_cast(), llvm::SCEV::FlagNSW, llvm::SCEV::FlagNUW, IncrementAnyWrap, IncrementNSSW, IncrementNUSW, llvm::ScalarEvolution::setFlags(), and setFlags().

Referenced by llvm::PredicatedScalarEvolution::hasNoOverflow(), and llvm::PredicatedScalarEvolution::setNoOverflow().

◆ implies()

bool SCEVWrapPredicate::implies	(	const SCEVPredicate *	N,
		ScalarEvolution &	SE ) const

overridevirtual

Returns true if this predicate implies N.

Implements llvm::SCEVPredicate.

Definition at line 15088 of file ScalarEvolution.cpp.

References llvm::dyn_cast(), llvm::ScalarEvolution::getNoopOrSignExtend(), llvm::ScalarEvolution::getNoopOrZeroExtend(), llvm::SCEV::getType(), llvm::ScalarEvolution::getWiderType(), llvm::CmpInst::ICMP_SLE, llvm::CmpInst::ICMP_ULE, IncrementNSSW, IncrementNUSW, llvm::ScalarEvolution::isKnownPositive(), llvm::ScalarEvolution::isKnownPredicate(), llvm::Type::isPointerTy(), N, llvm::SCEVPredicate::SCEVPredicate(), and setFlags().

◆ isAlwaysTrue()

bool SCEVWrapPredicate::isAlwaysTrue ( ) const

overridevirtual

Returns true if the predicate is always true.

This means that no assumptions were made and nothing needs to be checked at run-time.

Implements llvm::SCEVPredicate.

Definition at line 15131 of file ScalarEvolution.cpp.

References clearFlags(), llvm::SCEV::FlagNSW, IncrementAnyWrap, IncrementNSSW, and llvm::ScalarEvolution::setFlags().

◆ maskFlags()

SCEVWrapPredicate::IncrementWrapFlags llvm::SCEVWrapPredicate::maskFlags	(	SCEVWrapPredicate::IncrementWrapFlags	Flags,
		int	Mask )

inlinestaticnodiscard

Definition at line 361 of file ScalarEvolution.h.

References assert(), and IncrementNoWrapMask.

◆ print()

void SCEVWrapPredicate::print	(	raw_ostream &	OS,
		unsigned	Depth = 0 ) const

overridevirtual

Prints a textual representation of this predicate with an indentation of Depth.

Implements llvm::SCEVPredicate.

Definition at line 15141 of file ScalarEvolution.cpp.

References llvm::Depth, getExpr(), getFlags(), IncrementNSSW, IncrementNUSW, and llvm::raw_ostream::indent().

◆ setFlags()

SCEVWrapPredicate::IncrementWrapFlags llvm::SCEVWrapPredicate::setFlags	(	SCEVWrapPredicate::IncrementWrapFlags	Flags,
		SCEVWrapPredicate::IncrementWrapFlags	OnFlags )

inlinestaticnodiscard

Definition at line 369 of file ScalarEvolution.h.

References assert(), and IncrementNoWrapMask.

Referenced by getImpliedFlags(), implies(), and llvm::PredicatedScalarEvolution::setNoOverflow().

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

include/llvm/Analysis/ScalarEvolution.h
lib/Analysis/ScalarEvolution.cpp

Public Types

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ IncrementWrapFlags

Constructor & Destructor Documentation

◆ SCEVWrapPredicate()

Member Function Documentation

◆ classof()

◆ clearFlags()

◆ getExpr()

◆ getFlags()

◆ getImpliedFlags()

◆ implies()

◆ isAlwaysTrue()

◆ maskFlags()

◆ print()

◆ setFlags()