#include "llvm/Support/KnownBits.h"

Collaboration diagram for llvm::KnownBits:

Public Member Functions
	KnownBits ()

	KnownBits (unsigned BitWidth)
	Create a known bits object of BitWidth bits initialized to unknown. More...

unsigned	getBitWidth () const
	Get the bit width of this value. More...

bool	hasConflict () const
	Returns true if there is conflicting information. More...

bool	isConstant () const
	Returns true if we know the value of all bits. More...

const APInt &	getConstant () const
	Returns the value when all bits have a known value. More...

bool	isUnknown () const
	Returns true if we don't know any bits. More...

void	resetAll ()
	Resets the known state of all bits. More...

bool	isZero () const
	Returns true if value is all zero. More...

bool	isAllOnes () const
	Returns true if value is all one bits. More...

void	setAllZero ()
	Make all bits known to be zero and discard any previous information. More...

void	setAllOnes ()
	Make all bits known to be one and discard any previous information. More...

bool	isNegative () const
	Returns true if this value is known to be negative. More...

bool	isNonNegative () const
	Returns true if this value is known to be non-negative. More...

void	makeNegative ()
	Make this value negative. More...

void	makeNonNegative ()
	Make this value non-negative. More...

KnownBits	trunc (unsigned BitWidth) const
	Truncate the underlying known Zero and One bits. More...

KnownBits	zext (unsigned BitWidth, bool ExtendedBitsAreKnownZero) const
	Extends the underlying known Zero and One bits. More...

KnownBits	sext (unsigned BitWidth) const
	Sign extends the underlying known Zero and One bits. More...

KnownBits	zextOrTrunc (unsigned BitWidth, bool ExtendedBitsAreKnownZero) const
	Extends or truncates the underlying known Zero and One bits. More...

unsigned	countMinTrailingZeros () const
	Returns the minimum number of trailing zero bits. More...

unsigned	countMinTrailingOnes () const
	Returns the minimum number of trailing one bits. More...

unsigned	countMinLeadingZeros () const
	Returns the minimum number of leading zero bits. More...

unsigned	countMinLeadingOnes () const
	Returns the minimum number of leading one bits. More...

unsigned	countMinSignBits () const
	Returns the number of times the sign bit is replicated into the other bits. More...

unsigned	countMaxTrailingZeros () const
	Returns the maximum number of trailing zero bits possible. More...

unsigned	countMaxTrailingOnes () const
	Returns the maximum number of trailing one bits possible. More...

unsigned	countMaxLeadingZeros () const
	Returns the maximum number of leading zero bits possible. More...

unsigned	countMaxLeadingOnes () const
	Returns the maximum number of leading one bits possible. More...

unsigned	countMinPopulation () const
	Returns the number of bits known to be one. More...

unsigned	countMaxPopulation () const
	Returns the maximum number of bits that could be one. More...

Static Public Member Functions
static KnownBits	computeForAddCarry (const KnownBits &LHS, const KnownBits &RHS, const KnownBits &Carry)
	Compute known bits resulting from adding LHS, RHS and a 1-bit Carry. More...

static KnownBits	computeForAddSub (bool Add, bool NSW, const KnownBits &LHS, KnownBits RHS)
	Compute known bits resulting from adding LHS and RHS. More...

Public Attributes
APInt	Zero

APInt	One

Detailed Description

Definition at line 22 of file KnownBits.h.

Constructor & Destructor Documentation

◆ KnownBits() [1/2]

llvm::KnownBits::KnownBits ( )

inline

Definition at line 33 of file KnownBits.h.

Referenced by sext(), trunc(), zext(), and zextOrTrunc().

◆ KnownBits() [2/2]

llvm::KnownBits::KnownBits ( unsigned BitWidth )

inline

Create a known bits object of BitWidth bits initialized to unknown.

Definition at line 36 of file KnownBits.h.

Member Function Documentation

◆ computeForAddCarry()

KnownBits KnownBits::computeForAddCarry	(	const KnownBits &	LHS,
		const KnownBits &	RHS,
		const KnownBits &	Carry
	)

static

Compute known bits resulting from adding LHS, RHS and a 1-bit Carry.

Definition at line 47 of file KnownBits.cpp.

References assert(), computeForAddCarry(), getBitWidth(), llvm::APInt::getBoolValue(), One, and Zero.

Referenced by computeForAddSub(), llvm::SelectionDAG::computeKnownBits(), and countMaxPopulation().

◆ computeForAddSub()

KnownBits KnownBits::computeForAddSub	(	bool	Add,
		bool	NSW,
		const KnownBits &	LHS,
		KnownBits	RHS
	)

static

Compute known bits resulting from adding LHS and RHS.

Definition at line 54 of file KnownBits.cpp.

References computeForAddCarry(), isNegative(), isNonNegative(), makeNegative(), makeNonNegative(), One, std::swap(), and Zero.

Referenced by llvm::SelectionDAG::computeKnownBits(), computeKnownBitsAddSub(), computeKnownBitsFromOperator(), countMaxPopulation(), and ShrinkDemandedConstant().

◆ countMaxLeadingOnes()

unsigned llvm::KnownBits::countMaxLeadingOnes ( ) const

inline

Returns the maximum number of leading one bits possible.

Definition at line 191 of file KnownBits.h.

References llvm::APInt::countLeadingZeros().

◆ countMaxLeadingZeros()

unsigned llvm::KnownBits::countMaxLeadingZeros ( ) const

inline

Returns the maximum number of leading zero bits possible.

Definition at line 186 of file KnownBits.h.

References llvm::APInt::countLeadingZeros().

Referenced by llvm::SelectionDAG::computeKnownBits(), computeKnownBitsFromOperator(), foldCttzCtlz(), isAlwaysLive(), and isKnownNonZero().

◆ countMaxPopulation()

unsigned llvm::KnownBits::countMaxPopulation ( ) const

inline

Returns the maximum number of bits that could be one.

Definition at line 201 of file KnownBits.h.

References llvm::MCID::Add, computeForAddCarry(), computeForAddSub(), llvm::APInt::countPopulation(), and getBitWidth().

Referenced by llvm::SelectionDAG::computeKnownBits(), computeKnownBitsFromOperator(), foldCtpop(), and llvm::SelectionDAG::isKnownToBeAPowerOfTwo().

◆ countMaxTrailingOnes()

unsigned llvm::KnownBits::countMaxTrailingOnes ( ) const

inline

Returns the maximum number of trailing one bits possible.

Definition at line 181 of file KnownBits.h.

References llvm::APInt::countTrailingZeros().

◆ countMaxTrailingZeros()

unsigned llvm::KnownBits::countMaxTrailingZeros ( ) const

inline

Returns the maximum number of trailing zero bits possible.

Definition at line 176 of file KnownBits.h.

References llvm::APInt::countTrailingZeros().

Referenced by llvm::SelectionDAG::computeKnownBits(), foldCttzCtlz(), and isAlwaysLive().

◆ countMinLeadingOnes()

unsigned llvm::KnownBits::countMinLeadingOnes ( ) const

inline

Returns the minimum number of leading one bits.

Definition at line 161 of file KnownBits.h.

References llvm::APInt::countLeadingOnes().

Referenced by llvm::SelectionDAG::computeKnownBits(), computeKnownBitsFromOperator(), and countMinSignBits().

◆ countMinLeadingZeros()

unsigned llvm::KnownBits::countMinLeadingZeros ( ) const

inline

◆ countMinPopulation()

unsigned llvm::KnownBits::countMinPopulation ( ) const

inline

Returns the number of bits known to be one.

Definition at line 196 of file KnownBits.h.

References llvm::APInt::countPopulation().

Referenced by foldCtpop(), and llvm::SelectionDAG::isKnownToBeAPowerOfTwo().

◆ countMinSignBits()

unsigned llvm::KnownBits::countMinSignBits ( ) const

inline

Returns the number of times the sign bit is replicated into the other bits.

Definition at line 167 of file KnownBits.h.

References countMinLeadingOnes(), countMinLeadingZeros(), isNegative(), and isNonNegative().

Referenced by llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), and ComputeNumSignBitsImpl().

◆ countMinTrailingOnes()

unsigned llvm::KnownBits::countMinTrailingOnes ( ) const

inline

Returns the minimum number of trailing one bits.

Definition at line 151 of file KnownBits.h.

References llvm::APInt::countTrailingOnes().

Referenced by computeKnownBitsFromOperator().

◆ countMinTrailingZeros()

unsigned llvm::KnownBits::countMinTrailingZeros ( ) const

inline

Returns the minimum number of trailing zero bits.

Definition at line 146 of file KnownBits.h.

References llvm::APInt::countTrailingOnes().

Referenced by llvm::SelectionDAG::computeKnownBits(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromOperator(), computeKnownBitsMul(), foldCttzCtlz(), llvm::SelectionDAG::InferPtrAlignment(), isKnownNonZero(), isWordAligned(), llvm::InstCombiner::replacedSelectWithOperand(), and SimplifyShift().

◆ getBitWidth()

unsigned llvm::KnownBits::getBitWidth ( ) const

inline

Get the bit width of this value.

Definition at line 39 of file KnownBits.h.

References assert(), and llvm::APInt::getBitWidth().

Referenced by computeForAddCarry(), computeKnownBits(), llvm::SelectionDAG::computeKnownBits(), computeKnownBitsAddSub(), llvm::LanaiTargetLowering::computeKnownBitsForTargetNode(), llvm::AArch64TargetLowering::computeKnownBitsForTargetNode(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), llvm::ARMTargetLowering::computeKnownBitsForTargetNode(), llvm::SystemZTargetLowering::computeKnownBitsForTargetNode(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromAssume(), computeKnownBitsFromOperator(), llvm::computeKnownBitsFromRangeMetadata(), computeKnownBitsFromShiftOperator(), computeKnownBitsMul(), computeSignedMinMaxValuesFromKnownBits(), computeUnsignedMinMaxValuesFromKnownBits(), countMaxPopulation(), llvm::XCoreTargetLowering::EmitInstrWithCustomInserter(), llvm::ConstantRange::fromKnownBits(), llvm::FunctionLoweringInfo::GetLiveOutRegInfo(), isConstant(), llvm::AMDGPUTargetLowering::performTruncateCombine(), ShrinkDemandedConstant(), llvm::TargetLowering::SimplifyDemandedBits(), SimplifyShift(), tryBitfieldInsertOpFromOr(), zext(), and zextOrTrunc().

◆ getConstant()

const APInt& llvm::KnownBits::getConstant ( ) const

inline

Returns the value when all bits have a known value.

This just returns One with a protective assertion.

Definition at line 56 of file KnownBits.h.

References assert(), isConstant(), and One.

Referenced by llvm::ConstantFoldLoadFromConstPtr(), llvm::AMDGPUTargetLowering::performTruncateCombine(), llvm::InstCombiner::run(), llvm::SimplifyInstruction(), and llvm::InstCombiner::visitReturnInst().

◆ hasConflict()

bool llvm::KnownBits::hasConflict ( ) const

inline

Returns true if there is conflicting information.

Definition at line 46 of file KnownBits.h.

References llvm::APInt::intersects().

Referenced by llvm::SelectionDAG::computeKnownBits(), computeKnownBitsFromShiftOperator(), computeKnownBitsMul(), llvm::ConstantRange::fromKnownBits(), isAllOnes(), isConstant(), isZero(), ShrinkDemandedConstant(), llvm::TargetLowering::SimplifyDemandedBits(), and llvm::X86TargetLowering::SimplifyDemandedBitsForTargetNode().

◆ isAllOnes()

bool llvm::KnownBits::isAllOnes ( ) const

inline

Returns true if value is all one bits.

Definition at line 77 of file KnownBits.h.

References assert(), hasConflict(), and llvm::APInt::isAllOnesValue().

Referenced by computeKnownBitsFromAssume().

◆ isConstant()

bool llvm::KnownBits::isConstant ( ) const

inline

Returns true if we know the value of all bits.

Definition at line 49 of file KnownBits.h.

References assert(), llvm::APInt::countPopulation(), getBitWidth(), and hasConflict().

Referenced by llvm::ConstantFoldLoadFromConstPtr(), getConstant(), llvm::AMDGPUTargetLowering::performTruncateCombine(), llvm::InstCombiner::run(), llvm::SimplifyInstruction(), and llvm::InstCombiner::visitReturnInst().

◆ isNegative()

bool llvm::KnownBits::isNegative ( ) const

inline

Returns true if this value is known to be negative.

Definition at line 95 of file KnownBits.h.

References llvm::APInt::isSignBitSet().

Referenced by aliasSameBasePointerGEPs(), computeForAddSub(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromAssume(), computeKnownBitsFromOperator(), computeKnownBitsMul(), llvm::SelectionDAG::ComputeNumSignBits(), computeRecurrenceType(), countMinSignBits(), EvaluateConstantChrecAtConstant(), llvm::ConstantRange::fromKnownBits(), llvm::isKnownNegative(), isKnownNonZero(), simplifyICmpWithBinOp(), and simplifyICmpWithZero().

◆ isNonNegative()

bool llvm::KnownBits::isNonNegative ( ) const

inline

Returns true if this value is known to be non-negative.

Definition at line 98 of file KnownBits.h.

References llvm::APInt::isSignBitSet().

Referenced by aliasSameBasePointerGEPs(), canReplaceGEPIdxWithZero(), computeForAddSub(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromAssume(), computeKnownBitsFromOperator(), computeKnownBitsMul(), llvm::slpvectorizer::BoUpSLP::computeMinimumValueSizes(), llvm::SelectionDAG::ComputeNumSignBits(), ComputeNumSignBitsImpl(), llvm::computeOverflowForSignedMul(), computeRecurrenceType(), countMinSignBits(), EvaluateConstantChrecAtConstant(), llvm::ConstantRange::fromKnownBits(), llvm::isKnownNonNegative(), isKnownNonZero(), ShrinkDemandedConstant(), simplifyICmpWithBinOp(), simplifyICmpWithZero(), llvm::InstCombiner::simplifyRangeCheck(), and llvm::InstCombiner::visitSExt().

◆ isUnknown()

bool llvm::KnownBits::isUnknown ( ) const

inline

Returns true if we don't know any bits.

Definition at line 62 of file KnownBits.h.

References llvm::APInt::isNullValue().

Referenced by llvm::FunctionLoweringInfo::AddLiveOutRegInfo(), llvm::SelectionDAG::computeKnownBits(), llvm::ARMTargetLowering::computeKnownBitsForTargetNode(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), and llvm::ConstantRange::fromKnownBits().

◆ isZero()

bool llvm::KnownBits::isZero ( ) const

inline

Returns true if value is all zero.

Definition at line 71 of file KnownBits.h.

References assert(), hasConflict(), and llvm::APInt::isAllOnesValue().

Referenced by computeKnownBitsFromAssume(), isZero(), and llvm::InstCombiner::replacedSelectWithOperand().

◆ makeNegative()

void llvm::KnownBits::makeNegative ( )

inline

Make this value negative.

Definition at line 101 of file KnownBits.h.

References llvm::APInt::setSignBit().

Referenced by computeForAddSub(), computeKnownBitsFromAssume(), computeKnownBitsFromOperator(), and computeKnownBitsMul().

◆ makeNonNegative()

void llvm::KnownBits::makeNonNegative ( )

inline

Make this value non-negative.

Definition at line 106 of file KnownBits.h.

References llvm::APInt::setSignBit().

Referenced by computeForAddSub(), computeKnownBitsFromAssume(), computeKnownBitsFromOperator(), computeKnownBitsMul(), and ShrinkDemandedConstant().

◆ resetAll()

void llvm::KnownBits::resetAll ( )

inline

Resets the known state of all bits.

Definition at line 65 of file KnownBits.h.

References llvm::APInt::clearAllBits().

Referenced by computeKnownBits(), llvm::SelectionDAG::computeKnownBits(), llvm::SparcTargetLowering::computeKnownBitsForTargetNode(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), llvm::ARMTargetLowering::computeKnownBitsForTargetNode(), llvm::SystemZTargetLowering::computeKnownBitsForTargetNode(), llvm::PPCTargetLowering::computeKnownBitsForTargetNode(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), llvm::TargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromAssume(), computeKnownBitsFromOperator(), computeKnownBitsFromShiftOperator(), computeKnownBitsMul(), llvm::XCoreTargetLowering::EmitInstrWithCustomInserter(), and ShrinkDemandedConstant().

◆ setAllOnes()

void llvm::KnownBits::setAllOnes ( )

inline

Make all bits known to be one and discard any previous information.

Definition at line 89 of file KnownBits.h.

References llvm::APInt::clearAllBits(), and llvm::APInt::setAllBits().

Referenced by computeKnownBitsFromAssume().

◆ setAllZero()

void llvm::KnownBits::setAllZero ( )

inline

Make all bits known to be zero and discard any previous information.

Definition at line 83 of file KnownBits.h.

References llvm::APInt::clearAllBits(), and llvm::APInt::setAllBits().

Referenced by computeKnownBits(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromAssume(), and computeKnownBitsFromShiftOperator().

◆ sext()

KnownBits llvm::KnownBits::sext ( unsigned BitWidth ) const

inline

Sign extends the underlying known Zero and One bits.

This is equivalent to sign extending the value we're tracking.

Definition at line 130 of file KnownBits.h.

References KnownBits(), and llvm::APInt::sext().

Referenced by llvm::SelectionDAG::computeKnownBits(), llvm::ARMTargetLowering::computeKnownBitsForTargetNode(), llvm::SystemZTargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromOperator(), and ShrinkDemandedConstant().

◆ trunc()

KnownBits llvm::KnownBits::trunc ( unsigned BitWidth ) const

inline

Truncate the underlying known Zero and One bits.

This is equivalent to truncating the value we're tracking.

Definition at line 112 of file KnownBits.h.

References KnownBits(), and llvm::APInt::trunc().

Referenced by llvm::SelectionDAG::computeKnownBits(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromOperator(), llvm::TargetLowering::SimplifyDemandedBits(), and llvm::X86TargetLowering::SimplifyDemandedBitsForTargetNode().

◆ zext()

KnownBits llvm::KnownBits::zext	(	unsigned	BitWidth,
		bool	ExtendedBitsAreKnownZero
	)		const

inline

Extends the underlying known Zero and One bits.

By setting ExtendedBitsAreKnownZero=true this will be equivalent to zero extending the value we're tracking. With ExtendedBitsAreKnownZero=false the extended bits are set to unknown.

Definition at line 120 of file KnownBits.h.

References getBitWidth(), KnownBits(), llvm::APInt::setBitsFrom(), and llvm::APInt::zext().

Referenced by llvm::SelectionDAG::computeKnownBits(), llvm::ARMTargetLowering::computeKnownBitsForTargetNode(), llvm::SystemZTargetLowering::computeKnownBitsForTargetNode(), llvm::FunctionLoweringInfo::GetLiveOutRegInfo(), llvm::X86TargetLowering::SimplifyDemandedBitsForTargetNode(), and zextOrTrunc().

◆ zextOrTrunc()

KnownBits llvm::KnownBits::zextOrTrunc	(	unsigned	BitWidth,
		bool	ExtendedBitsAreKnownZero
	)		const

inline

Extends or truncates the underlying known Zero and One bits.

When extending the extended bits can either be set as known zero (if ExtendedBitsAreKnownZero=true) or as unknown (if ExtendedBitsAreKnownZero=false).

Definition at line 138 of file KnownBits.h.

References getBitWidth(), KnownBits(), zext(), and llvm::APInt::zextOrTrunc().

Referenced by llvm::SystemZTargetLowering::computeKnownBitsForTargetNode(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromOperator(), ShrinkDemandedConstant(), and llvm::TargetLowering::SimplifyDemandedBits().

Member Data Documentation

◆ One

APInt llvm::KnownBits::One

Definition at line 24 of file KnownBits.h.

Referenced by llvm::FunctionLoweringInfo::AddLiveOutRegInfo(), aliasSameBasePointerGEPs(), llvm::SelectionDAGISel::CheckOrMask(), computeForAddCarry(), computeForAddCarry(), computeForAddSub(), computeKnownBits(), llvm::SelectionDAG::computeKnownBits(), computeKnownBitsBinOp(), llvm::SparcTargetLowering::computeKnownBitsForTargetNode(), llvm::LanaiTargetLowering::computeKnownBitsForTargetNode(), llvm::AArch64TargetLowering::computeKnownBitsForTargetNode(), llvm::AMDGPUTargetLowering::computeKnownBitsForTargetNode(), llvm::ARMTargetLowering::computeKnownBitsForTargetNode(), llvm::X86TargetLowering::computeKnownBitsForTargetNode(), computeKnownBitsFromAssume(), computeKnownBitsFromOperator(), llvm::computeKnownBitsFromRangeMetadata(), computeKnownBitsFromShiftOperator(), computeKnownBitsMul(), llvm::SelectionDAG::ComputeNumSignBits(), llvm::FunctionLoweringInfo::ComputePHILiveOutRegInfo(), computeSignedMinMaxValuesFromKnownBits(), computeUnsignedMinMaxValuesFromKnownBits(), llvm::ConstantFoldLoadFromConstPtr(), foldCttzCtlz(), llvm::ConstantRange::fromKnownBits(), generateEquivalentSub(), getConstant(), GetRangeFromMetadata(), isAlwaysLive(), isKnownNonEqual(), isKnownNonZero(), isKnownToBeAPowerOfTwo(), isOpcWithIntImmediate(), maskMatters(), processUGT_ADDCST_ADD(), llvm::InstCombiner::replacedSelectWithOperand(), ShrinkDemandedConstant(), llvm::TargetLowering::SimplifyDemandedBits(), llvm::X86TargetLowering::SimplifyDemandedBitsForTargetNode(), SimplifyRightShift(), SimplifyShift(), stripTruncAndExt(), and llvm::InstCombiner::visitTrunc().

◆ Zero

APInt llvm::KnownBits::Zero

Definition at line 23 of file KnownBits.h.

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

include/llvm/Support/KnownBits.h
lib/Support/KnownBits.cpp

Public Member Functions

Static Public Member Functions

Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ KnownBits() [1/2]

◆ KnownBits() [2/2]

Member Function Documentation

◆ computeForAddCarry()

◆ computeForAddSub()

◆ countMaxLeadingOnes()

◆ countMaxLeadingZeros()

◆ countMaxPopulation()

◆ countMaxTrailingOnes()

◆ countMaxTrailingZeros()

◆ countMinLeadingOnes()

◆ countMinLeadingZeros()

◆ countMinPopulation()

◆ countMinSignBits()

◆ countMinTrailingOnes()

◆ countMinTrailingZeros()

◆ getBitWidth()

◆ getConstant()

◆ hasConflict()

◆ isAllOnes()

◆ isConstant()

◆ isNegative()

◆ isNonNegative()

◆ isUnknown()

◆ isZero()

◆ makeNegative()

◆ makeNonNegative()

◆ resetAll()

◆ setAllOnes()

◆ setAllZero()

◆ sext()

◆ trunc()

◆ zext()

◆ zextOrTrunc()

Member Data Documentation

◆ One

◆ Zero