This is an important base class in LLVM. More...

#include "llvm/IR/Constant.h"

Inheritance diagram for llvm::Constant:

[legend]

Public Member Functions
void	operator= (const Constant &)=delete

	Constant (const Constant &)=delete

bool	isNullValue () const
	Return true if this is the value that would be returned by getNullValue.

bool	isOneValue () const
	Returns true if the value is one.

bool	isNotOneValue () const
	Return true if the value is not the one value, or, for vectors, does not contain one value elements.

bool	isAllOnesValue () const
	Return true if this is the value that would be returned by getAllOnesValue.

bool	isNegativeZeroValue () const
	Return true if the value is what would be returned by getZeroValueForNegation.

bool	isZeroValue () const
	Return true if the value is negative zero or null value.

bool	isNotMinSignedValue () const
	Return true if the value is not the smallest signed value, or, for vectors, does not contain smallest signed value elements.

bool	isMinSignedValue () const
	Return true if the value is the smallest signed value.

bool	isFiniteNonZeroFP () const
	Return true if this is a finite and non-zero floating-point scalar constant or a fixed width vector constant with all finite and non-zero elements.

bool	isNormalFP () const
	Return true if this is a normal (as opposed to denormal, infinity, nan, or zero) floating-point scalar constant or a vector constant with all normal elements.

bool	hasExactInverseFP () const
	Return true if this scalar has an exact multiplicative inverse or this vector has an exact multiplicative inverse for each element in the vector.

bool	isNaN () const
	Return true if this is a floating-point NaN constant or a vector floating-point constant with all NaN elements.

bool	isElementWiseEqual (Value *Y) const
	Return true if this constant and a constant 'Y' are element-wise equal.

bool	containsUndefOrPoisonElement () const
	Return true if this is a vector constant that includes any undef or poison elements.

bool	containsPoisonElement () const
	Return true if this is a vector constant that includes any poison elements.

bool	containsUndefElement () const
	Return true if this is a vector constant that includes any strictly undef (not poison) elements.

bool	containsConstantExpression () const
	Return true if this is a fixed width vector constant that includes any constant expressions.

bool	isThreadDependent () const
	Return true if the value can vary between threads.

bool	isDLLImportDependent () const
	Return true if the value is dependent on a dllimport variable.

bool	isConstantUsed () const
	Return true if the constant has users other than constant expressions and other dangling things.

bool	needsRelocation () const
	This method classifies the entry according to whether or not it may generate a relocation entry (either static or dynamic).

bool	needsDynamicRelocation () const

Constant *	getAggregateElement (unsigned Elt) const
	For aggregates (struct/array/vector) return the constant that corresponds to the specified element if possible, or null if not.

Constant *	getAggregateElement (Constant *Elt) const

Constant *	getSplatValue (bool AllowUndefs=false) const
	If all elements of the vector constant have the same value, return that value.

const APInt &	getUniqueInteger () const
	If C is a constant integer then return its value, otherwise C must be a vector of constant integers, all equal, and the common value is returned.

void	destroyConstant ()
	Called if some element of this constant is no longer valid.

void	handleOperandChange (Value , Value )
	This method is a special form of User::replaceUsesOfWith (which does not work on constants) that does work on constants.

void	removeDeadConstantUsers () const
	If there are any dead constant users dangling off of this constant, remove them.

bool	hasOneLiveUse () const
	Return true if the constant has exactly one live use.

bool	hasZeroLiveUses () const
	Return true if the constant has no live uses.

const Constant *	stripPointerCasts () const

Constant *	stripPointerCasts ()

bool	isManifestConstant () const
	Return true if a constant is ConstantData or a ConstantAggregate or ConstantExpr that contain only ConstantData.

Public Member Functions inherited from llvm::User
	User (const User &)=delete

void	operator delete (void *Usr)
	Free memory allocated for User and Use objects.

void	operator delete (void *Usr, unsigned)
	Placement delete - required by std, called if the ctor throws.

void	operator delete (void *Usr, unsigned, unsigned)
	Placement delete - required by std, called if the ctor throws.

const Use *	getOperandList () const

Use *	getOperandList ()

Value *	getOperand (unsigned i) const

void	setOperand (unsigned i, Value *Val)

const Use &	getOperandUse (unsigned i) const

Use &	getOperandUse (unsigned i)

unsigned	getNumOperands () const

ArrayRef< const uint8_t >	getDescriptor () const
	Returns the descriptor co-allocated with this User instance.

MutableArrayRef< uint8_t >	getDescriptor ()
	Returns the descriptor co-allocated with this User instance.

void	setGlobalVariableNumOperands (unsigned NumOps)
	Set the number of operands on a GlobalVariable.

void	setNumHungOffUseOperands (unsigned NumOps)
	Subclasses with hung off uses need to manage the operand count themselves.

bool	isDroppable () const
	A droppable user is a user for which uses can be dropped without affecting correctness and should be dropped rather than preventing a transformation from happening.

op_iterator	op_begin ()

const_op_iterator	op_begin () const

op_iterator	op_end ()

const_op_iterator	op_end () const

op_range	operands ()

const_op_range	operands () const

value_op_iterator	value_op_begin ()

value_op_iterator	value_op_end ()

iterator_range< value_op_iterator >	operand_values ()

const_value_op_iterator	value_op_begin () const

const_value_op_iterator	value_op_end () const

iterator_range< const_value_op_iterator >	operand_values () const

void	dropAllReferences ()
	Drop all references to operands.

bool	replaceUsesOfWith (Value From, Value To)
	Replace uses of one Value with another.

Public Member Functions inherited from llvm::Value
	Value (const Value &)=delete

Value &	operator= (const Value &)=delete

void	deleteValue ()
	Delete a pointer to a generic Value.

void	dump () const
	Support for debugging, callable in GDB: V->dump()

Type *	getType () const
	All values are typed, get the type of this value.

LLVMContext &	getContext () const
	All values hold a context through their type.

bool	hasName () const

ValueName *	getValueName () const

void	setValueName (ValueName *VN)

StringRef	getName () const
	Return a constant reference to the value's name.

void	setName (const Twine &Name)
	Change the name of the value.

void	takeName (Value *V)
	Transfer the name from V to this value.

std::string	getNameOrAsOperand () const

void	replaceAllUsesWith (Value *V)
	Change all uses of this to point to a new Value.

void	replaceNonMetadataUsesWith (Value *V)
	Change non-metadata uses of this to point to a new Value.

void	replaceUsesWithIf (Value *New, llvm::function_ref< bool(Use &U)> ShouldReplace)
	Go through the uses list for this definition and make each use point to "V" if the callback ShouldReplace returns true for the given Use.

void	replaceUsesOutsideBlock (Value V, BasicBlock BB)
	replaceUsesOutsideBlock - Go through the uses list for this definition and make each use point to "V" instead of "this" when the use is outside the block.

void	assertModuleIsMaterializedImpl () const

void	assertModuleIsMaterialized () const

bool	use_empty () const

bool	materialized_use_empty () const

use_iterator	materialized_use_begin ()

const_use_iterator	materialized_use_begin () const

use_iterator	use_begin ()

const_use_iterator	use_begin () const

use_iterator	use_end ()

const_use_iterator	use_end () const

iterator_range< use_iterator >	materialized_uses ()

iterator_range< const_use_iterator >	materialized_uses () const

iterator_range< use_iterator >	uses ()

iterator_range< const_use_iterator >	uses () const

bool	user_empty () const

user_iterator	materialized_user_begin ()

const_user_iterator	materialized_user_begin () const

user_iterator	user_begin ()

const_user_iterator	user_begin () const

user_iterator	user_end ()

const_user_iterator	user_end () const

User *	user_back ()

const User *	user_back () const

iterator_range< user_iterator >	materialized_users ()

iterator_range< const_user_iterator >	materialized_users () const

iterator_range< user_iterator >	users ()

iterator_range< const_user_iterator >	users () const

bool	hasOneUse () const
	Return true if there is exactly one use of this value.

bool	hasNUses (unsigned N) const
	Return true if this Value has exactly N uses.

bool	hasNUsesOrMore (unsigned N) const
	Return true if this value has N uses or more.

bool	hasOneUser () const
	Return true if there is exactly one user of this value.

Use *	getSingleUndroppableUse ()
	Return true if there is exactly one use of this value that cannot be dropped.

const Use *	getSingleUndroppableUse () const

User *	getUniqueUndroppableUser ()
	Return true if there is exactly one unique user of this value that cannot be dropped (that user can have multiple uses of this value).

const User *	getUniqueUndroppableUser () const

bool	hasNUndroppableUses (unsigned N) const
	Return true if there this value.

bool	hasNUndroppableUsesOrMore (unsigned N) const
	Return true if this value has N uses or more.

void	dropDroppableUses (llvm::function_ref< bool(const Use )> ShouldDrop=[](const Use ) { return true;})
	Remove every uses that can safely be removed.

void	dropDroppableUsesIn (User &Usr)
	Remove every use of this value in `User` that can safely be removed.

bool	isUsedInBasicBlock (const BasicBlock *BB) const
	Check if this value is used in the specified basic block.

unsigned	getNumUses () const
	This method computes the number of uses of this Value.

void	addUse (Use &U)
	This method should only be used by the Use class.

unsigned	getValueID () const
	Return an ID for the concrete type of this object.

unsigned	getRawSubclassOptionalData () const
	Return the raw optional flags value contained in this value.

void	clearSubclassOptionalData ()
	Clear the optional flags contained in this value.

bool	hasSameSubclassOptionalData (const Value *V) const
	Check the optional flags for equality.

bool	hasValueHandle () const
	Return true if there is a value handle associated with this value.

bool	isUsedByMetadata () const
	Return true if there is metadata referencing this value.

bool	isSwiftError () const
	Return true if this value is a swifterror value.

const Value *	stripPointerCasts () const
	Strip off pointer casts, all-zero GEPs and address space casts.

Value *	stripPointerCasts ()

const Value *	stripPointerCastsAndAliases () const
	Strip off pointer casts, all-zero GEPs, address space casts, and aliases.

Value *	stripPointerCastsAndAliases ()

const Value *	stripPointerCastsSameRepresentation () const
	Strip off pointer casts, all-zero GEPs and address space casts but ensures the representation of the result stays the same.

Value *	stripPointerCastsSameRepresentation ()

const Value *	stripPointerCastsForAliasAnalysis () const
	Strip off pointer casts, all-zero GEPs, single-argument phi nodes and invariant group info.

Value *	stripPointerCastsForAliasAnalysis ()

const Value *	stripInBoundsConstantOffsets () const
	Strip off pointer casts and all-constant inbounds GEPs.

Value *	stripInBoundsConstantOffsets ()

const Value *	stripAndAccumulateConstantOffsets (const DataLayout &DL, APInt &Offset, bool AllowNonInbounds, bool AllowInvariantGroup=false, function_ref< bool(Value &Value, APInt &Offset)> ExternalAnalysis=nullptr) const
	Accumulate the constant offset this value has compared to a base pointer.

Value *	stripAndAccumulateConstantOffsets (const DataLayout &DL, APInt &Offset, bool AllowNonInbounds, bool AllowInvariantGroup=false)

const Value *	stripAndAccumulateInBoundsConstantOffsets (const DataLayout &DL, APInt &Offset) const
	This is a wrapper around stripAndAccumulateConstantOffsets with the in-bounds requirement set to false.

Value *	stripAndAccumulateInBoundsConstantOffsets (const DataLayout &DL, APInt &Offset)

const Value *	stripInBoundsOffsets (function_ref< void(const Value )> Func=[](const Value ) {}) const
	Strip off pointer casts and inbounds GEPs.

Value *	stripInBoundsOffsets (function_ref< void(const Value )> Func=[](const Value ) {})

std::optional< int64_t >	getPointerOffsetFrom (const Value *Other, const DataLayout &DL) const
	If this ptr is provably equal to `Other` plus a constant offset, return that offset in bytes.

bool	canBeFreed () const
	Return true if the memory object referred to by V can by freed in the scope for which the SSA value defining the allocation is statically defined.

uint64_t	getPointerDereferenceableBytes (const DataLayout &DL, bool &CanBeNull, bool &CanBeFreed) const
	Returns the number of bytes known to be dereferenceable for the pointer value.

Align	getPointerAlignment (const DataLayout &DL) const
	Returns an alignment of the pointer value.

const Value *	DoPHITranslation (const BasicBlock CurBB, const BasicBlock PredBB) const
	Translate PHI node to its predecessor from the given basic block.

Value *	DoPHITranslation (const BasicBlock CurBB, const BasicBlock PredBB)

void	mutateType (Type *Ty)
	Mutate the type of this Value to be of the specified type.

template<class Compare >
void	sortUseList (Compare Cmp)
	Sort the use-list.

void	reverseUseList ()
	Reverse the use-list.

void	print (raw_ostream &O, bool IsForDebug=false) const
	Implement operator<< on Value.

void	print (raw_ostream &O, ModuleSlotTracker &MST, bool IsForDebug=false) const

void	printAsOperand (raw_ostream &O, bool PrintType=true, const Module *M=nullptr) const
	Print the name of this Value out to the specified raw_ostream.

void	printAsOperand (raw_ostream &O, bool PrintType, ModuleSlotTracker &MST) const

Static Public Member Functions
static bool	classof (const Value *V)

static Constant *	getNullValue (Type *Ty)
	Constructor to create a '0' constant of arbitrary type.

static Constant *	getAllOnesValue (Type *Ty)

static Constant *	getIntegerValue (Type *Ty, const APInt &V)
	Return the value for an integer or pointer constant, or a vector thereof, with the given scalar value.

static Constant *	replaceUndefsWith (Constant C, Constant Replacement)
	Try to replace undefined constant C or undefined elements in C with Replacement.

static Constant *	mergeUndefsWith (Constant C, Constant Other)
	Merges undefs of a Constant with another Constant, along with the undefs already present.

Static Public Member Functions inherited from llvm::User
static bool	classof (const Value *V)

Static Public Member Functions inherited from llvm::Value
static void	dropDroppableUse (Use &U)
	Remove the droppable use `U`.

Protected Member Functions
	Constant (Type ty, ValueTy vty, Use Ops, unsigned NumOps)

	~Constant ()=default

Protected Member Functions inherited from llvm::User
void *	operator new (size_t Size)
	Allocate a User with an operand pointer co-allocated.

void *	operator new (size_t Size, unsigned Us)
	Allocate a User with the operands co-allocated.

void *	operator new (size_t Size, unsigned Us, unsigned DescBytes)
	Allocate a User with the operands co-allocated.

	User (Type ty, unsigned vty, Use , unsigned NumOps)

void	allocHungoffUses (unsigned N, bool IsPhi=false)
	Allocate the array of Uses, followed by a pointer (with bottom bit set) to the User.

void	growHungoffUses (unsigned N, bool IsPhi=false)
	Grow the number of hung off uses.

	~User ()=default

template<int Idx>
Use &	Op ()

template<int Idx>
const Use &	Op () const

Protected Member Functions inherited from llvm::Value
	Value (Type *Ty, unsigned scid)

	~Value ()
	Value's destructor should be virtual by design, but that would require that Value and all of its subclasses have a vtable that effectively duplicates the information in the value ID.

void	getAllMetadata (SmallVectorImpl< std::pair< unsigned, MDNode * > > &MDs) const
	Appends all metadata attached to this value to `MDs`, sorting by KindID.

bool	hasMetadata () const
	Return true if this value has any metadata attached to it.

bool	eraseMetadata (unsigned KindID)
	Erase all metadata attachments with the given kind.

void	clearMetadata ()
	Erase all metadata attached to this Value.

unsigned short	getSubclassDataFromValue () const

void	setValueSubclassData (unsigned short D)

MDNode *	getMetadata (unsigned KindID) const
	Get the current metadata attachments for the given kind, if any.

MDNode *	getMetadata (StringRef Kind) const

void	getMetadata (unsigned KindID, SmallVectorImpl< MDNode * > &MDs) const
	Appends all attachments with the given ID to `MDs` in insertion order.

void	getMetadata (StringRef Kind, SmallVectorImpl< MDNode * > &MDs) const

bool	hasMetadata (unsigned KindID) const
	Return true if this value has the given type of metadata attached.

bool	hasMetadata (StringRef Kind) const

void	setMetadata (unsigned KindID, MDNode *Node)
	Set a particular kind of metadata attachment.

void	setMetadata (StringRef Kind, MDNode *Node)

void	addMetadata (unsigned KindID, MDNode &MD)
	Add a metadata attachment.

void	addMetadata (StringRef Kind, MDNode &MD)

Additional Inherited Members
Public Types inherited from llvm::User
using	op_iterator = Use *

using	const_op_iterator = const Use *

using	op_range = iterator_range< op_iterator >

using	const_op_range = iterator_range< const_op_iterator >

Public Types inherited from llvm::Value
enum	ValueTy
	Concrete subclass of this. More...

using	use_iterator = use_iterator_impl< Use >

using	const_use_iterator = use_iterator_impl< const Use >

using	user_iterator = user_iterator_impl< User >

using	const_user_iterator = user_iterator_impl< const User >

Static Public Attributes inherited from llvm::Value
static constexpr unsigned	MaxAlignmentExponent = 32
	The maximum alignment for instructions.

static constexpr uint64_t	MaximumAlignment = 1ULL << MaxAlignmentExponent

Protected Types inherited from llvm::Value
enum	: unsigned { NumUserOperandsBits = 27 }
	The number of operands in the subclass. More...

Static Protected Member Functions inherited from llvm::User
template<int Idx, typename U >
static Use &	OpFrom (const U *that)

Protected Attributes inherited from llvm::Value
unsigned char	SubclassOptionalData: 7
	Hold subclass data that can be dropped.

unsigned	NumUserOperands: NumUserOperandsBits

unsigned	IsUsedByMD: 1

unsigned	HasName: 1

unsigned	HasMetadata: 1

unsigned	HasHungOffUses: 1

unsigned	HasDescriptor: 1

Detailed Description

This is an important base class in LLVM.

It provides the common facilities of all constant values in an LLVM program. A constant is a value that is immutable at runtime. Functions are constants because their address is immutable. Same with global variables.

All constants share the capabilities provided in this class. All constants can have a null value. They can have an operand list. Constants can be simple (integer and floating point values), complex (arrays and structures), or expression based (computations yielding a constant value composed of only certain operators and other constant values).

Note that Constants are immutable (once created they never change) and are fully shared by structural equivalence. This means that two structurally equivalent constants will always have the same address. Constants are created on demand as needed and never deleted: thus clients don't have to worry about the lifetime of the objects. LLVM Constant Representation

Definition at line 41 of file Constant.h.

Constructor & Destructor Documentation

◆ Constant() [1/2]

llvm::Constant::Constant	(	Type *	ty,
		ValueTy	vty,
		Use *	Ops,
		unsigned	NumOps
	)

inlineprotected

Definition at line 43 of file Constant.h.

◆ ~Constant()

llvm::Constant::~Constant ( )

protecteddefault

◆ Constant() [2/2]

llvm::Constant::Constant ( const Constant & )

delete

Member Function Documentation

◆ classof()

static bool llvm::Constant::classof ( const Value * V )

inlinestatic

Definition at line 167 of file Constant.h.

◆ containsConstantExpression()

bool Constant::containsConstantExpression ( ) const

Return true if this is a fixed width vector constant that includes any constant expressions.

Definition at line 346 of file Constants.cpp.

References getAggregateElement(), and llvm::Value::getType().

◆ containsPoisonElement()

bool Constant::containsPoisonElement ( ) const

Return true if this is a vector constant that includes any poison elements.

Definition at line 335 of file Constants.cpp.

References llvm::CallingConv::C, and containsUndefinedElement().

◆ containsUndefElement()

bool Constant::containsUndefElement ( ) const

Return true if this is a vector constant that includes any strictly undef (not poison) elements.

Definition at line 340 of file Constants.cpp.

References llvm::CallingConv::C, and containsUndefinedElement().

Referenced by llvm::InstCombinerImpl::visitShl().

◆ containsUndefOrPoisonElement()

bool Constant::containsUndefOrPoisonElement ( ) const

Return true if this is a vector constant that includes any undef or poison elements.

Since it is impossible to inspect a scalable vector element- wise at compile time, this function returns true only if the entire vector is undef or poison.

Definition at line 330 of file Constants.cpp.

References llvm::CallingConv::C, and containsUndefinedElement().

◆ destroyConstant()

void Constant::destroyConstant ( )

Called if some element of this constant is no longer valid.

At this point only other constants may be on the use_list for this constant. Any constants on our Use list must also be destroy'd. The implementation must be sure to remove the constant from the list of available cached constants. Implementations should implement destroyConstantImpl to remove constants from any pools/maps they are contained it.

First call destroyConstantImpl on the subclass. This gives the subclass a chance to remove the constant from any maps/pools it's contained in.

Definition at line 458 of file Constants.cpp.

References assert(), llvm::dbgs(), llvm::deleteConstant(), llvm::Value::getValueID(), llvm_unreachable, llvm::Value::use_empty(), and llvm::Value::user_back().

Referenced by handleOperandChange(), llvm::MergeBasicBlockIntoOnlyPred(), and llvm::BasicBlock::~BasicBlock().

◆ getAggregateElement() [1/2]

Constant * Constant::getAggregateElement ( Constant * Elt ) const

Definition at line 447 of file Constants.cpp.

References assert(), getAggregateElement(), and llvm::Value::getType().

◆ getAggregateElement() [2/2]

Constant * Constant::getAggregateElement ( unsigned Elt ) const

For aggregates (struct/array/vector) return the constant that corresponds to the specified element if possible, or null if not.

This can return null if the element index is a ConstantExpr, if 'this' is a constant expr or if the constant does not fit into an uint64_t.

Definition at line 418 of file Constants.cpp.

References assert(), CC, and llvm::Value::getType().

Referenced by areInverseVectorBitmasks(), CheckAndCreateOffsetAdd(), checkOffsetSize(), computeKnownBits(), llvm::SelectionDAG::computeKnownBits(), computeKnownFPClass(), llvm::SelectionDAG::ComputeNumSignBits(), llvm::ConstantFoldExtractElementInstruction(), llvm::ConstantFoldExtractValueInstruction(), llvm::ConstantFoldInsertValueInstruction(), containsConstantExpression(), foldConstantInsEltIntoShuffle(), foldICmpWithLowBitMaskedVal(), getAggregateElement(), getSplatableConstant(), getTargetConstantBitsFromNode(), getUniqueInteger(), hasExactInverseFP(), isFiniteNonZeroFP(), isNaN(), isNormalFP(), isNotMinSignedValue(), isNotOneValue(), matchStridedConstant(), llvm::InstCombinerImpl::SimplifyDemandedVectorElts(), simplifyDivRem(), simplifySelectInst(), and WriteConstantInternal().

◆ getAllOnesValue()

Constant * Constant::getAllOnesValue ( Type * Ty )

static

Returns: the value for an integer or vector of integer constant of the given type that has all its bits set to true. Get the all ones value

Definition at line 403 of file Constants.cpp.

References llvm::ConstantFP::get(), llvm::ConstantInt::get(), llvm::APInt::getAllOnes(), llvm::APFloat::getAllOnesValue(), getAllOnesValue(), llvm::Type::getContext(), llvm::VectorType::getElementCount(), llvm::VectorType::getElementType(), llvm::Type::getFltSemantics(), llvm::ConstantVector::getSplat(), and llvm::Type::isFloatingPointTy().

◆ getIntegerValue()

Constant * Constant::getIntegerValue	(	Type *	Ty,
		const APInt &	V
	)

static

Return the value for an integer or pointer constant, or a vector thereof, with the given scalar value.

Definition at line 386 of file Constants.cpp.

References llvm::CallingConv::C, llvm::ConstantInt::get(), llvm::Type::getContext(), llvm::ConstantExpr::getIntToPtr(), llvm::Type::getScalarType(), and llvm::ConstantVector::getSplat().

Referenced by constantFoldUser(), createIRLevelProfileFlagVar(), llvm::InstCombinerImpl::foldBinOpOfSelectAndCastOfSelectCondition(), foldCtpopPow2Test(), llvm::InstCombinerImpl::foldICmpBinOp(), llvm::InstCombinerImpl::foldICmpUsingKnownBits(), getConstantVector(), llvm::MinMaxIntrinsic::getSaturationPoint(), llvm::InstCombinerImpl::SimplifyDemandedUseBits(), llvm::InstCombinerImpl::SimplifyMultipleUseDemandedBits(), simplifyX86pack(), and llvm::InstCombinerImpl::visitCallInst().

◆ getNullValue()

Constant * Constant::getNullValue ( Type * Ty )

static

Constructor to create a '0' constant of arbitrary type.

Definition at line 356 of file Constants.cpp.

References llvm::Type::ArrayTyID, llvm::Type::BFloatTyID, llvm::Type::DoubleTyID, llvm::Type::FixedVectorTyID, llvm::Type::FloatTyID, llvm::Type::FP128TyID, llvm::ConstantTokenNone::get(), llvm::ConstantPointerNull::get(), llvm::ConstantTargetNone::get(), llvm::ConstantAggregateZero::get(), llvm::ConstantFP::get(), llvm::ConstantInt::get(), llvm::Type::getContext(), llvm::Type::getFltSemantics(), llvm::Type::getTypeID(), llvm::APFloat::getZero(), llvm::Type::HalfTyID, llvm::Type::IntegerTyID, llvm_unreachable, llvm::Type::PointerTyID, llvm::Type::PPC_FP128TyID, llvm::Type::ScalableVectorTyID, llvm::Type::StructTyID, llvm::Type::TargetExtTyID, llvm::Type::TokenTyID, and llvm::Type::X86_FP80TyID.

◆ getSplatValue()

Constant * Constant::getSplatValue ( bool AllowUndefs = false ) const

If all elements of the vector constant have the same value, return that value.

Otherwise, return nullptr. Ignore undefined elements by setting AllowUndefs to true.

Definition at line 1615 of file Constants.cpp.

References llvm::all_of(), assert(), getNullValue(), llvm::User::getOperand(), llvm::Value::getType(), and I.

Referenced by BitCastConstantVector(), llvm::SelectionDAG::computeKnownBits(), computeKnownBitsFromOperator(), llvm::ConstantFoldBinaryInstruction(), llvm::ConstantFoldCompareInstruction(), llvm::ConstantFoldExtractElementInstruction(), getUniqueInteger(), hasExactInverseFP(), isAllOnesValue(), isFiniteNonZeroFP(), isMinSignedValue(), isNaN(), isNegativeZeroValue(), isNormalFP(), isNotMinSignedValue(), isNotOneValue(), isOneValue(), and isZeroValue().

◆ getUniqueInteger()

const APInt & Constant::getUniqueInteger ( ) const

If C is a constant integer then return its value, otherwise C must be a vector of constant integers, all equal, and the common value is returned.

Definition at line 1674 of file Constants.cpp.

References assert(), llvm::CallingConv::C, getAggregateElement(), and getSplatValue().

Referenced by foldShiftIntoShiftInAnotherHandOfAndInICmp().

◆ handleOperandChange()

void Constant::handleOperandChange	(	Value *	From,
		Value *	To
	)

This method is a special form of User::replaceUsesOfWith (which does not work on constants) that does work on constants.

Update this constant array to change uses of 'From' to be uses of 'To'.

Basically this method goes through the trouble of building a new constant that is equivalent to the current one, with all uses of From replaced with uses of To. After this construction is completed, all of the users of 'this' are replaced to use the new constant, and then 'this' is deleted. In general, you should not call this method, instead, use Value::replaceAllUsesWith, which automatically dispatches to this method as needed.

This must update the uniquing data structures etc.

Note that we intentionally replace all uses of From with To here. Consider a large array that uses 'From' 1000 times. By handling this case all here, ConstantArray::handleOperandChange is only invoked once, and that single invocation handles all 1000 uses. Handling them one at a time would work, but would be really slow because it would have to unique each updated array instance.

Definition at line 3163 of file Constants.cpp.

References assert(), destroyConstant(), llvm::Value::getValueID(), llvm_unreachable, and llvm::Value::replaceAllUsesWith().

◆ hasExactInverseFP()

bool Constant::hasExactInverseFP ( ) const

Return true if this scalar has an exact multiplicative inverse or this vector has an exact multiplicative inverse for each element in the vector.

Definition at line 242 of file Constants.cpp.

References E, getAggregateElement(), getSplatValue(), llvm::Value::getType(), and I.

◆ hasOneLiveUse()

bool Constant::hasOneLiveUse ( ) const

Return true if the constant has exactly one live use.

This returns the same result as calling Value::hasOneUse after Constant::removeDeadConstantUsers, but doesn't remove dead constants.

Definition at line 735 of file Constants.cpp.

◆ hasZeroLiveUses()

bool Constant::hasZeroLiveUses ( ) const

Return true if the constant has no live uses.

This returns the same result as calling Value::use_empty after Constant::removeDeadConstantUsers, but doesn't remove dead constants.

Definition at line 737 of file Constants.cpp.

◆ isAllOnesValue()

bool Constant::isAllOnesValue ( ) const

Return true if this is the value that would be returned by getAllOnesValue.

Definition at line 93 of file Constants.cpp.

References getSplatValue(), and llvm::Value::getType().

Referenced by BitCastConstantVector(), llvm::InstCombinerImpl::foldICmpSelectConstant(), llvm::InstCombinerImpl::SimplifyDemandedVectorElts(), and simplifyICmpInst().

◆ isConstantUsed()

bool Constant::isConstantUsed ( ) const

Return true if the constant has users other than constant expressions and other dangling things.

Definition at line 607 of file Constants.cpp.

References isConstantUsed(), and llvm::Value::users().

Referenced by findPartitions(), and isConstantUsed().

◆ isDLLImportDependent()

bool Constant::isDLLImportDependent ( ) const

Return true if the value is dependent on a dllimport variable.

Definition at line 600 of file Constants.cpp.

References ConstHasGlobalValuePredicate().

◆ isElementWiseEqual()

bool Constant::isElementWiseEqual ( Value * Y ) const

Return true if this constant and a constant 'Y' are element-wise equal.

This is identical to just comparing the pointers, with the exception that for vectors, if only one of the constants has an undef element in some lane, the constants still match.

Definition at line 284 of file Constants.cpp.

References llvm::ConstantExpr::getBitCast(), llvm::ConstantExpr::getICmp(), llvm::VectorType::getInteger(), llvm::Value::getType(), llvm::CmpInst::ICMP_EQ, llvm::PatternMatch::m_One(), llvm::PatternMatch::match(), and Y.

Referenced by llvm::InstCombinerImpl::visitSExt().

◆ isFiniteNonZeroFP()

bool Constant::isFiniteNonZeroFP ( ) const

Return true if this is a finite and non-zero floating-point scalar constant or a fixed width vector constant with all finite and non-zero elements.

Definition at line 200 of file Constants.cpp.

References E, getAggregateElement(), getSplatValue(), llvm::Value::getType(), and I.

◆ isManifestConstant()

bool Constant::isManifestConstant ( ) const

Return true if a constant is ConstantData or a ConstantAggregate or ConstantExpr that contain only ConstantData.

Definition at line 812 of file Constants.cpp.

References isManifestConstant(), and llvm::User::operand_values().

Referenced by isManifestConstant().

◆ isMinSignedValue()

bool Constant::isMinSignedValue ( ) const

Return true if the value is the smallest signed value.

Definition at line 155 of file Constants.cpp.

References getSplatValue(), and llvm::Value::getType().

◆ isNaN()

bool Constant::isNaN ( ) const

Return true if this is a floating-point NaN constant or a vector floating-point constant with all NaN elements.

Definition at line 263 of file Constants.cpp.

References E, getAggregateElement(), getSplatValue(), llvm::Value::getType(), and I.

Referenced by propagateNaN().

◆ isNegativeZeroValue()

bool Constant::isNegativeZeroValue ( ) const

Return true if the value is what would be returned by getZeroValueForNegation.

Definition at line 42 of file Constants.cpp.

References getSplatValue(), llvm::Value::getType(), and isNullValue().

◆ isNormalFP()

bool Constant::isNormalFP ( ) const

Return true if this is a normal (as opposed to denormal, infinity, nan, or zero) floating-point scalar constant or a vector constant with all normal elements.

See APFloat::isNormal.

Definition at line 221 of file Constants.cpp.

References E, getAggregateElement(), getSplatValue(), llvm::Value::getType(), and I.

Referenced by foldFDivConstantDividend(), and llvm::InstCombinerImpl::visitFMul().

◆ isNotMinSignedValue()

bool Constant::isNotMinSignedValue ( ) const

Return true if the value is not the smallest signed value, or, for vectors, does not contain smallest signed value elements.

Definition at line 172 of file Constants.cpp.

References E, getAggregateElement(), getSplatValue(), llvm::Value::getType(), I, and isNotMinSignedValue().

Referenced by isNotMinSignedValue(), and llvm::InstCombinerImpl::visitMul().

◆ isNotOneValue()

bool Constant::isNotOneValue ( ) const

Return true if the value is not the one value, or, for vectors, does not contain one value elements.

Definition at line 127 of file Constants.cpp.

References E, getAggregateElement(), getSplatValue(), llvm::Value::getType(), I, and isNotOneValue().

Referenced by isNotOneValue().

◆ isNullValue()

bool Constant::isNullValue ( ) const

Return true if this is the value that would be returned by getNullValue.

Definition at line 76 of file Constants.cpp.

Referenced by addConditions(), addTryBlockMapEntry(), llvm::ScalarEvolution::applyLoopGuards(), BitCastConstantVector(), calculateSEHStateNumbers(), constantFoldCompareGlobalToNull(), llvm::ConstantFoldCompareInstOperands(), llvm::ConstantFoldCompareInstruction(), llvm::ConstantFoldGetElementPtr(), llvm::ConstantFoldInsertElementInstruction(), llvm::ConstantFoldShuffleVectorInstruction(), foldGEPOfGEP(), llvm::InstCombinerImpl::foldICmpInstWithConstantNotInt(), foldShiftIntoShiftInAnotherHandOfAndInICmp(), foldSwitchToSelect(), llvm::getConstantDataArrayInfo(), getPredicateResult(), llvm::GCNTTIImpl::instCombineIntrinsic(), isCatchAll(), isKnownNonZero(), isNegativeZeroValue(), isZeroValue(), llvm::AsmPrinter::lowerConstant(), optimizeOnceStoredGlobal(), runImpl(), ShouldUseSwitchConditionAsTableIndex(), llvm::InstCombinerImpl::SimplifyDemandedVectorElts(), simplifyDivRem(), simplifyICmpInst(), llvm::ScalarEvolution::SimplifyICmpOperands(), and TryToShrinkGlobalToBoolean().

◆ isOneValue()

bool Constant::isOneValue ( ) const

Returns true if the value is one.

Definition at line 110 of file Constants.cpp.

References getSplatValue(), and llvm::Value::getType().

Referenced by findBestNonTrivialUnswitchCandidate(), and unswitchNontrivialInvariants().

◆ isThreadDependent()

bool Constant::isThreadDependent ( ) const

Return true if the value can vary between threads.

Definition at line 593 of file Constants.cpp.

References ConstHasGlobalValuePredicate().

◆ isZeroValue()

bool Constant::isZeroValue ( ) const

Return true if the value is negative zero or null value.

Definition at line 62 of file Constants.cpp.

References getSplatValue(), llvm::Value::getType(), and isNullValue().

Referenced by computeKnownBitsFromOperator(), shouldConvertImpl(), and llvm::InstCombinerImpl::visitXor().

◆ mergeUndefsWith()

Constant * Constant::mergeUndefsWith	(	Constant *	C,
		Constant *	Other
	)

static

Merges undefs of a Constant with another Constant, along with the undefs already present.

Other doesn't have to be the same type as C, but both must either be scalars or vectors with the same element count. If no changes are made, the constant C is returned.

Definition at line 777 of file Constants.cpp.

References assert(), llvm::CallingConv::C, llvm::ConstantVector::get(), llvm::UndefValue::get(), I, llvm::PatternMatch::m_Undef(), llvm::PatternMatch::match(), and llvm::Other.

Referenced by foldSelectZeroOrMul(), matchFunnelShift(), llvm::InstCombinerImpl::visitAnd(), llvm::InstCombinerImpl::visitAShr(), llvm::InstCombinerImpl::visitSExt(), llvm::InstCombinerImpl::visitTrunc(), and llvm::InstCombinerImpl::visitXor().

◆ needsDynamicRelocation()

bool Constant::needsDynamicRelocation ( ) const

Definition at line 619 of file Constants.cpp.

◆ needsRelocation()

bool Constant::needsRelocation ( ) const

This method classifies the entry according to whether or not it may generate a relocation entry (either static or dynamic).

This must be conservative, so if it might codegen to a relocatable entry, it should say so.

FIXME: This really should not be in IR.

Definition at line 623 of file Constants.cpp.

◆ operator=()

void llvm::Constant::operator= ( const Constant & )

delete

◆ removeDeadConstantUsers()

void Constant::removeDeadConstantUsers ( ) const

If there are any dead constant users dangling off of this constant, remove them.

This method is useful for clients that want to check to see if a global is unused, but don't want to deal with potentially dead constants hanging off of the globals.

Definition at line 708 of file Constants.cpp.

References constantIsDead(), E, I, llvm::Value::user_begin(), and llvm::Value::user_end().

Referenced by CleanupConstantGlobalUsers(), CleanupPointerRootUsers(), deleteIfDead(), llvm::CallGraphUpdater::finalize(), hasAddressTakenAndUsed(), mustPreserveGV(), llvm::CallGraphUpdater::replaceFunctionWith(), llvm::GlobalDCEPass::run(), SRAGlobal(), and llvm::GlobalValue::~GlobalValue().

◆ replaceUndefsWith()

Constant * Constant::replaceUndefsWith	(	Constant *	C,
		Constant *	Replacement
	)

static

Try to replace undefined constant C or undefined elements in C with Replacement.

If no changes are made, the constant C is returned.

Definition at line 753 of file Constants.cpp.

References assert(), llvm::CallingConv::C, llvm::ConstantVector::get(), llvm::Value::getType(), llvm::PatternMatch::m_Undef(), and llvm::PatternMatch::match().

Referenced by dropRedundantMaskingOfLeftShiftInput(), foldICmpWithLowBitMaskedVal(), llvm::InstCombiner::getFlippedStrictnessPredicateAndConstant(), llvm::InstCombinerImpl::visitAnd(), llvm::InstCombinerImpl::visitFreeze(), visitMaskedMerge(), and llvm::InstCombinerImpl::visitXor().

◆ stripPointerCasts() [1/2]

Constant * llvm::Constant::stripPointerCasts ( )

inline

Definition at line 217 of file Constant.h.

References stripPointerCasts().

◆ stripPointerCasts() [2/2]

const Constant * llvm::Constant::stripPointerCasts ( ) const

inline

Definition at line 213 of file Constant.h.

References llvm::Value::stripPointerCasts().

Referenced by addTryBlockMapEntry(), llvm::ARMAsmPrinter::emitXXStructor(), hasUsesToReplace(), llvm::InlineFunction(), OptimizeGlobalAliases(), runImpl(), stripPointerCasts(), and llvm::InstCombinerImpl::visitLandingPadInst().

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

include/llvm/IR/Constant.h
lib/IR/Constants.cpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Constant() [1/2]

◆ ~Constant()

◆ Constant() [2/2]

Member Function Documentation

◆ classof()

◆ containsConstantExpression()

◆ containsPoisonElement()

◆ containsUndefElement()

◆ containsUndefOrPoisonElement()

◆ destroyConstant()

◆ getAggregateElement() [1/2]

◆ getAggregateElement() [2/2]

◆ getAllOnesValue()

◆ getIntegerValue()

◆ getNullValue()

◆ getSplatValue()

◆ getUniqueInteger()

◆ handleOperandChange()

◆ hasExactInverseFP()

◆ hasOneLiveUse()

◆ hasZeroLiveUses()

◆ isAllOnesValue()

◆ isConstantUsed()

◆ isDLLImportDependent()

◆ isElementWiseEqual()

◆ isFiniteNonZeroFP()

◆ isManifestConstant()

◆ isMinSignedValue()

◆ isNaN()

◆ isNegativeZeroValue()

◆ isNormalFP()

◆ isNotMinSignedValue()

◆ isNotOneValue()

◆ isNullValue()

◆ isOneValue()

◆ isThreadDependent()

◆ isZeroValue()

◆ mergeUndefsWith()

◆ needsDynamicRelocation()

◆ needsRelocation()

◆ operator=()

◆ removeDeadConstantUsers()

◆ replaceUndefsWith()

◆ stripPointerCasts() [1/2]

◆ stripPointerCasts() [2/2]