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llvm::ScalarEvolution Class Reference

The main scalar evolution driver. More...

#include "llvm/Analysis/ScalarEvolution.h"

Classes

struct  LoopInvariantPredicate
 

Public Types

enum  LoopDisposition { LoopVariant, LoopInvariant, LoopComputable }
 An enum describing the relationship between a SCEV and a loop. More...
 
enum  BlockDisposition { DoesNotDominateBlock, DominatesBlock, ProperlyDominatesBlock }
 An enum describing the relationship between a SCEV and a basic block. More...
 
enum  ExitCountKind { Exact, ConstantMaximum, SymbolicMaximum }
 The terms "backedge taken count" and "exit count" are used interchangeably to refer to the number of times the backedge of a loop has executed before the loop is exited. More...
 
enum  MonotonicPredicateType { MonotonicallyIncreasing, MonotonicallyDecreasing }
 A predicate is said to be monotonically increasing if may go from being false to being true as the loop iterates, but never the other way around. More...
 

Public Member Functions

 ScalarEvolution (Function &F, TargetLibraryInfo &TLI, AssumptionCache &AC, DominatorTree &DT, LoopInfo &LI)
 
 ScalarEvolution (ScalarEvolution &&Arg)
 
 ~ScalarEvolution ()
 
LLVMContextgetContext () const
 
bool isSCEVable (Type *Ty) const
 Test if values of the given type are analyzable within the SCEV framework. More...
 
uint64_t getTypeSizeInBits (Type *Ty) const
 Return the size in bits of the specified type, for which isSCEVable must return true. More...
 
TypegetEffectiveSCEVType (Type *Ty) const
 Return a type with the same bitwidth as the given type and which represents how SCEV will treat the given type, for which isSCEVable must return true. More...
 
TypegetWiderType (Type *Ty1, Type *Ty2) const
 
bool containsAddRecurrence (const SCEV *S)
 Return true if the SCEV is a scAddRecExpr or it contains scAddRecExpr. More...
 
void eraseValueFromMap (Value *V)
 Erase Value from ValueExprMap and ExprValueMap. More...
 
bool willNotOverflow (Instruction::BinaryOps BinOp, bool Signed, const SCEV *LHS, const SCEV *RHS)
 Is operation BinOp between LHS and RHS provably does not have a signed/unsigned overflow (Signed)? More...
 
std::pair< SCEV::NoWrapFlags, bool > getStrengthenedNoWrapFlagsFromBinOp (const OverflowingBinaryOperator *OBO)
 Parse NSW/NUW flags from add/sub/mul IR binary operation Op into SCEV no-wrap flags, and deduce flag[s] that aren't known yet. More...
 
const SCEVgetSCEV (Value *V)
 Return a SCEV expression for the full generality of the specified expression. More...
 
const SCEVgetConstant (ConstantInt *V)
 
const SCEVgetConstant (const APInt &Val)
 
const SCEVgetConstant (Type *Ty, uint64_t V, bool isSigned=false)
 
const SCEVgetLosslessPtrToIntExpr (const SCEV *Op, unsigned Depth=0)
 
const SCEVgetPtrToIntExpr (const SCEV *Op, Type *Ty)
 
const SCEVgetTruncateExpr (const SCEV *Op, Type *Ty, unsigned Depth=0)
 
const SCEVgetZeroExtendExpr (const SCEV *Op, Type *Ty, unsigned Depth=0)
 
const SCEVgetSignExtendExpr (const SCEV *Op, Type *Ty, unsigned Depth=0)
 
const SCEVgetAnyExtendExpr (const SCEV *Op, Type *Ty)
 getAnyExtendExpr - Return a SCEV for the given operand extended with unspecified bits out to the given type. More...
 
const SCEVgetAddExpr (SmallVectorImpl< const SCEV * > &Ops, SCEV::NoWrapFlags Flags=SCEV::FlagAnyWrap, unsigned Depth=0)
 Get a canonical add expression, or something simpler if possible. More...
 
const SCEVgetAddExpr (const SCEV *LHS, const SCEV *RHS, SCEV::NoWrapFlags Flags=SCEV::FlagAnyWrap, unsigned Depth=0)
 
const SCEVgetAddExpr (const SCEV *Op0, const SCEV *Op1, const SCEV *Op2, SCEV::NoWrapFlags Flags=SCEV::FlagAnyWrap, unsigned Depth=0)
 
const SCEVgetMulExpr (SmallVectorImpl< const SCEV * > &Ops, SCEV::NoWrapFlags Flags=SCEV::FlagAnyWrap, unsigned Depth=0)
 Get a canonical multiply expression, or something simpler if possible. More...
 
const SCEVgetMulExpr (const SCEV *LHS, const SCEV *RHS, SCEV::NoWrapFlags Flags=SCEV::FlagAnyWrap, unsigned Depth=0)
 
const SCEVgetMulExpr (const SCEV *Op0, const SCEV *Op1, const SCEV *Op2, SCEV::NoWrapFlags Flags=SCEV::FlagAnyWrap, unsigned Depth=0)
 
const SCEVgetUDivExpr (const SCEV *LHS, const SCEV *RHS)
 Get a canonical unsigned division expression, or something simpler if possible. More...
 
const SCEVgetUDivExactExpr (const SCEV *LHS, const SCEV *RHS)
 Get a canonical unsigned division expression, or something simpler if possible. More...
 
const SCEVgetURemExpr (const SCEV *LHS, const SCEV *RHS)
 Represents an unsigned remainder expression based on unsigned division. More...
 
const SCEVgetAddRecExpr (const SCEV *Start, const SCEV *Step, const Loop *L, SCEV::NoWrapFlags Flags)
 Get an add recurrence expression for the specified loop. More...
 
const SCEVgetAddRecExpr (SmallVectorImpl< const SCEV * > &Operands, const Loop *L, SCEV::NoWrapFlags Flags)
 Get an add recurrence expression for the specified loop. More...
 
const SCEVgetAddRecExpr (const SmallVectorImpl< const SCEV * > &Operands, const Loop *L, SCEV::NoWrapFlags Flags)
 
Optional< std::pair< const SCEV *, SmallVector< const SCEVPredicate *, 3 > > > createAddRecFromPHIWithCasts (const SCEVUnknown *SymbolicPHI)
 Checks if SymbolicPHI can be rewritten as an AddRecExpr under some Predicates. More...
 
const SCEVgetGEPExpr (GEPOperator *GEP, const SmallVectorImpl< const SCEV * > &IndexExprs)
 Returns an expression for a GEP. More...
 
const SCEVgetAbsExpr (const SCEV *Op, bool IsNSW)
 
const SCEVgetMinMaxExpr (SCEVTypes Kind, SmallVectorImpl< const SCEV * > &Operands)
 
const SCEVgetSMaxExpr (const SCEV *LHS, const SCEV *RHS)
 
const SCEVgetSMaxExpr (SmallVectorImpl< const SCEV * > &Operands)
 
const SCEVgetUMaxExpr (const SCEV *LHS, const SCEV *RHS)
 
const SCEVgetUMaxExpr (SmallVectorImpl< const SCEV * > &Operands)
 
const SCEVgetSMinExpr (const SCEV *LHS, const SCEV *RHS)
 
const SCEVgetSMinExpr (SmallVectorImpl< const SCEV * > &Operands)
 
const SCEVgetUMinExpr (const SCEV *LHS, const SCEV *RHS)
 
const SCEVgetUMinExpr (SmallVectorImpl< const SCEV * > &Operands)
 
const SCEVgetUnknown (Value *V)
 
const SCEVgetCouldNotCompute ()
 
const SCEVgetZero (Type *Ty)
 Return a SCEV for the constant 0 of a specific type. More...
 
const SCEVgetOne (Type *Ty)
 Return a SCEV for the constant 1 of a specific type. More...
 
const SCEVgetMinusOne (Type *Ty)
 Return a SCEV for the constant -1 of a specific type. More...
 
const SCEVgetSizeOfScalableVectorExpr (Type *IntTy, ScalableVectorType *ScalableTy)
 Return an expression for sizeof ScalableTy that is type IntTy, where ScalableTy is a scalable vector type. More...
 
const SCEVgetSizeOfExpr (Type *IntTy, Type *AllocTy)
 Return an expression for the alloc size of AllocTy that is type IntTy. More...
 
const SCEVgetStoreSizeOfExpr (Type *IntTy, Type *StoreTy)
 Return an expression for the store size of StoreTy that is type IntTy. More...
 
const SCEVgetOffsetOfExpr (Type *IntTy, StructType *STy, unsigned FieldNo)
 Return an expression for offsetof on the given field with type IntTy. More...
 
const SCEVgetNegativeSCEV (const SCEV *V, SCEV::NoWrapFlags Flags=SCEV::FlagAnyWrap)
 Return the SCEV object corresponding to -V. More...
 
const SCEVgetNotSCEV (const SCEV *V)
 Return the SCEV object corresponding to ~V. More...
 
const SCEVgetMinusSCEV (const SCEV *LHS, const SCEV *RHS, SCEV::NoWrapFlags Flags=SCEV::FlagAnyWrap, unsigned Depth=0)
 Return LHS-RHS. More...
 
const SCEVgetUDivCeilSCEV (const SCEV *N, const SCEV *D)
 Compute ceil(N / D). More...
 
const SCEVgetTruncateOrZeroExtend (const SCEV *V, Type *Ty, unsigned Depth=0)
 Return a SCEV corresponding to a conversion of the input value to the specified type. More...
 
const SCEVgetTruncateOrSignExtend (const SCEV *V, Type *Ty, unsigned Depth=0)
 Return a SCEV corresponding to a conversion of the input value to the specified type. More...
 
const SCEVgetNoopOrZeroExtend (const SCEV *V, Type *Ty)
 Return a SCEV corresponding to a conversion of the input value to the specified type. More...
 
const SCEVgetNoopOrSignExtend (const SCEV *V, Type *Ty)
 Return a SCEV corresponding to a conversion of the input value to the specified type. More...
 
const SCEVgetNoopOrAnyExtend (const SCEV *V, Type *Ty)
 Return a SCEV corresponding to a conversion of the input value to the specified type. More...
 
const SCEVgetTruncateOrNoop (const SCEV *V, Type *Ty)
 Return a SCEV corresponding to a conversion of the input value to the specified type. More...
 
const SCEVgetUMaxFromMismatchedTypes (const SCEV *LHS, const SCEV *RHS)
 Promote the operands to the wider of the types using zero-extension, and then perform a umax operation with them. More...
 
const SCEVgetUMinFromMismatchedTypes (const SCEV *LHS, const SCEV *RHS)
 Promote the operands to the wider of the types using zero-extension, and then perform a umin operation with them. More...
 
const SCEVgetUMinFromMismatchedTypes (SmallVectorImpl< const SCEV * > &Ops)
 Promote the operands to the wider of the types using zero-extension, and then perform a umin operation with them. More...
 
const SCEVgetPointerBase (const SCEV *V)
 Transitively follow the chain of pointer-type operands until reaching a SCEV that does not have a single pointer operand. More...
 
const SCEVgetSCEVAtScope (const SCEV *S, const Loop *L)
 Return a SCEV expression for the specified value at the specified scope in the program. More...
 
const SCEVgetSCEVAtScope (Value *V, const Loop *L)
 This is a convenience function which does getSCEVAtScope(getSCEV(V), L). More...
 
bool isLoopEntryGuardedByCond (const Loop *L, ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS)
 Test whether entry to the loop is protected by a conditional between LHS and RHS. More...
 
bool isBasicBlockEntryGuardedByCond (const BasicBlock *BB, ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS)
 Test whether entry to the basic block is protected by a conditional between LHS and RHS. More...
 
bool isLoopBackedgeGuardedByCond (const Loop *L, ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS)
 Test whether the backedge of the loop is protected by a conditional between LHS and RHS. More...
 
const SCEVgetTripCountFromExitCount (const SCEV *ExitCount)
 Convert from an "exit count" (i.e. More...
 
unsigned getSmallConstantTripCount (const Loop *L)
 Returns the exact trip count of the loop if we can compute it, and the result is a small constant. More...
 
unsigned getSmallConstantTripCount (const Loop *L, const BasicBlock *ExitingBlock)
 Return the exact trip count for this loop if we exit through ExitingBlock. More...
 
unsigned getSmallConstantMaxTripCount (const Loop *L)
 Returns the upper bound of the loop trip count as a normal unsigned value. More...
 
unsigned getSmallConstantTripMultiple (const Loop *L, const SCEV *ExitCount)
 Returns the largest constant divisor of the trip count as a normal unsigned value, if possible. More...
 
unsigned getSmallConstantTripMultiple (const Loop *L)
 Returns the largest constant divisor of the trip count of the loop. More...
 
unsigned getSmallConstantTripMultiple (const Loop *L, const BasicBlock *ExitingBlock)
 Returns the largest constant divisor of the trip count of this loop as a normal unsigned value, if possible. More...
 
const SCEVgetExitCount (const Loop *L, const BasicBlock *ExitingBlock, ExitCountKind Kind=Exact)
 Return the number of times the backedge executes before the given exit would be taken; if not exactly computable, return SCEVCouldNotCompute. More...
 
const SCEVgetBackedgeTakenCount (const Loop *L, ExitCountKind Kind=Exact)
 If the specified loop has a predictable backedge-taken count, return it, otherwise return a SCEVCouldNotCompute object. More...
 
const SCEVgetPredicatedBackedgeTakenCount (const Loop *L, SCEVUnionPredicate &Predicates)
 Similar to getBackedgeTakenCount, except it will add a set of SCEV predicates to Predicates that are required to be true in order for the answer to be correct. More...
 
const SCEVgetConstantMaxBackedgeTakenCount (const Loop *L)
 When successful, this returns a SCEVConstant that is greater than or equal to (i.e. More...
 
const SCEVgetSymbolicMaxBackedgeTakenCount (const Loop *L)
 When successful, this returns a SCEV that is greater than or equal to (i.e. More...
 
bool isBackedgeTakenCountMaxOrZero (const Loop *L)
 Return true if the backedge taken count is either the value returned by getConstantMaxBackedgeTakenCount or zero. More...
 
bool hasLoopInvariantBackedgeTakenCount (const Loop *L)
 Return true if the specified loop has an analyzable loop-invariant backedge-taken count. More...
 
void forgetAllLoops ()
 
void forgetLoop (const Loop *L)
 This method should be called by the client when it has changed a loop in a way that may effect ScalarEvolution's ability to compute a trip count, or if the loop is deleted. More...
 
void forgetTopmostLoop (const Loop *L)
 
void forgetValue (Value *V)
 This method should be called by the client when it has changed a value in a way that may effect its value, or which may disconnect it from a def-use chain linking it to a loop. More...
 
void forgetLoopDispositions (const Loop *L)
 Called when the client has changed the disposition of values in this loop. More...
 
uint32_t GetMinTrailingZeros (const SCEV *S)
 Determine the minimum number of zero bits that S is guaranteed to end in (at every loop iteration). More...
 
ConstantRange getUnsignedRange (const SCEV *S)
 Determine the unsigned range for a particular SCEV. More...
 
APInt getUnsignedRangeMin (const SCEV *S)
 Determine the min of the unsigned range for a particular SCEV. More...
 
APInt getUnsignedRangeMax (const SCEV *S)
 Determine the max of the unsigned range for a particular SCEV. More...
 
ConstantRange getSignedRange (const SCEV *S)
 Determine the signed range for a particular SCEV. More...
 
APInt getSignedRangeMin (const SCEV *S)
 Determine the min of the signed range for a particular SCEV. More...
 
APInt getSignedRangeMax (const SCEV *S)
 Determine the max of the signed range for a particular SCEV. More...
 
bool isKnownNegative (const SCEV *S)
 Test if the given expression is known to be negative. More...
 
bool isKnownPositive (const SCEV *S)
 Test if the given expression is known to be positive. More...
 
bool isKnownNonNegative (const SCEV *S)
 Test if the given expression is known to be non-negative. More...
 
bool isKnownNonPositive (const SCEV *S)
 Test if the given expression is known to be non-positive. More...
 
bool isKnownNonZero (const SCEV *S)
 Test if the given expression is known to be non-zero. More...
 
std::pair< const SCEV *, const SCEV * > SplitIntoInitAndPostInc (const Loop *L, const SCEV *S)
 Splits SCEV expression S into two SCEVs. More...
 
bool isKnownViaInduction (ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS)
 We'd like to check the predicate on every iteration of the most dominated loop between loops used in LHS and RHS. More...
 
bool isKnownPredicate (ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS)
 Test if the given expression is known to satisfy the condition described by Pred, LHS, and RHS. More...
 
Optional< bool > evaluatePredicate (ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS)
 Check whether the condition described by Pred, LHS, and RHS is true or false. More...
 
bool isKnownPredicateAt (ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS, const Instruction *Context)
 Test if the given expression is known to satisfy the condition described by Pred, LHS, and RHS in the given Context. More...
 
Optional< bool > evaluatePredicateAt (ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS, const Instruction *Context)
 Check whether the condition described by Pred, LHS, and RHS is true or false in the given Context. More...
 
bool isKnownOnEveryIteration (ICmpInst::Predicate Pred, const SCEVAddRecExpr *LHS, const SCEV *RHS)
 Test if the condition described by Pred, LHS, RHS is known to be true on every iteration of the loop of the recurrency LHS. More...
 
Optional< MonotonicPredicateTypegetMonotonicPredicateType (const SCEVAddRecExpr *LHS, ICmpInst::Predicate Pred)
 If, for all loop invariant X, the predicate "LHS `Pred` X" is monotonically increasing or decreasing, returns Some(MonotonicallyIncreasing) and Some(MonotonicallyDecreasing) respectively. More...
 
Optional< LoopInvariantPredicategetLoopInvariantPredicate (ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS, const Loop *L)
 If the result of the predicate LHS Pred RHS is loop invariant with respect to L, return a LoopInvariantPredicate with LHS and RHS being invariants, available at L's entry. More...
 
Optional< LoopInvariantPredicategetLoopInvariantExitCondDuringFirstIterations (ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS, const Loop *L, const Instruction *Context, const SCEV *MaxIter)
 If the result of the predicate LHS Pred RHS is loop invariant with respect to L at given Context during at least first MaxIter iterations, return a LoopInvariantPredicate with LHS and RHS being invariants, available at L's entry. More...
 
bool SimplifyICmpOperands (ICmpInst::Predicate &Pred, const SCEV *&LHS, const SCEV *&RHS, unsigned Depth=0)
 Simplify LHS and RHS in a comparison with predicate Pred. More...
 
LoopDisposition getLoopDisposition (const SCEV *S, const Loop *L)
 Return the "disposition" of the given SCEV with respect to the given loop. More...
 
bool isLoopInvariant (const SCEV *S, const Loop *L)
 Return true if the value of the given SCEV is unchanging in the specified loop. More...
 
bool isAvailableAtLoopEntry (const SCEV *S, const Loop *L)
 Determine if the SCEV can be evaluated at loop's entry. More...
 
bool hasComputableLoopEvolution (const SCEV *S, const Loop *L)
 Return true if the given SCEV changes value in a known way in the specified loop. More...
 
BlockDisposition getBlockDisposition (const SCEV *S, const BasicBlock *BB)
 Return the "disposition" of the given SCEV with respect to the given block. More...
 
bool dominates (const SCEV *S, const BasicBlock *BB)
 Return true if elements that makes up the given SCEV dominate the specified basic block. More...
 
bool properlyDominates (const SCEV *S, const BasicBlock *BB)
 Return true if elements that makes up the given SCEV properly dominate the specified basic block. More...
 
bool hasOperand (const SCEV *S, const SCEV *Op) const
 Test whether the given SCEV has Op as a direct or indirect operand. More...
 
const SCEVgetElementSize (Instruction *Inst)
 Return the size of an element read or written by Inst. More...
 
void findArrayDimensions (SmallVectorImpl< const SCEV * > &Terms, SmallVectorImpl< const SCEV * > &Sizes, const SCEV *ElementSize)
 Compute the array dimensions Sizes from the set of Terms extracted from the memory access function of this SCEVAddRecExpr (second step of delinearization). More...
 
void print (raw_ostream &OS) const
 
void verify () const
 
bool invalidate (Function &F, const PreservedAnalyses &PA, FunctionAnalysisManager::Invalidator &Inv)
 
void collectParametricTerms (const SCEV *Expr, SmallVectorImpl< const SCEV * > &Terms)
 Collect parametric terms occurring in step expressions (first step of delinearization). More...
 
void computeAccessFunctions (const SCEV *Expr, SmallVectorImpl< const SCEV * > &Subscripts, SmallVectorImpl< const SCEV * > &Sizes)
 Return in Subscripts the access functions for each dimension in Sizes (third step of delinearization). More...
 
bool getIndexExpressionsFromGEP (const GetElementPtrInst *GEP, SmallVectorImpl< const SCEV * > &Subscripts, SmallVectorImpl< int > &Sizes)
 Gathers the individual index expressions from a GEP instruction. More...
 
void delinearize (const SCEV *Expr, SmallVectorImpl< const SCEV * > &Subscripts, SmallVectorImpl< const SCEV * > &Sizes, const SCEV *ElementSize)
 Split this SCEVAddRecExpr into two vectors of SCEVs representing the subscripts and sizes of an array access. More...
 
const DataLayoutgetDataLayout () const
 Return the DataLayout associated with the module this SCEV instance is operating on. More...
 
const SCEVPredicategetEqualPredicate (const SCEV *LHS, const SCEV *RHS)
 
const SCEVPredicategetWrapPredicate (const SCEVAddRecExpr *AR, SCEVWrapPredicate::IncrementWrapFlags AddedFlags)
 
const SCEVrewriteUsingPredicate (const SCEV *S, const Loop *L, SCEVUnionPredicate &A)
 Re-writes the SCEV according to the Predicates in A. More...
 
const SCEVAddRecExprconvertSCEVToAddRecWithPredicates (const SCEV *S, const Loop *L, SmallPtrSetImpl< const SCEVPredicate * > &Preds)
 Tries to convert the S expression to an AddRec expression, adding additional predicates to Preds as required. More...
 
Optional< APIntcomputeConstantDifference (const SCEV *LHS, const SCEV *RHS)
 Compute LHS - RHS and returns the result as an APInt if it is a constant, and None if it isn't. More...
 
void setNoWrapFlags (SCEVAddRecExpr *AddRec, SCEV::NoWrapFlags Flags)
 Update no-wrap flags of an AddRec. More...
 
const SCEVapplyLoopGuards (const SCEV *Expr, const Loop *L)
 Try to apply information from loop guards for L to Expr. More...
 

Static Public Member Functions

static LLVM_NODISCARD SCEV::NoWrapFlags maskFlags (SCEV::NoWrapFlags Flags, int Mask)
 Convenient NoWrapFlags manipulation that hides enum casts and is visible in the ScalarEvolution name space. More...
 
static LLVM_NODISCARD SCEV::NoWrapFlags setFlags (SCEV::NoWrapFlags Flags, SCEV::NoWrapFlags OnFlags)
 
static LLVM_NODISCARD SCEV::NoWrapFlags clearFlags (SCEV::NoWrapFlags Flags, SCEV::NoWrapFlags OffFlags)
 

Friends

class ScalarEvolutionsTest
 
class SCEVCallbackVH
 
class SCEVExpander
 
class SCEVUnknown
 

Detailed Description

The main scalar evolution driver.

Because client code (intentionally) can't do much with the SCEV objects directly, they must ask this class for services.

Definition at line 443 of file ScalarEvolution.h.

Member Enumeration Documentation

◆ BlockDisposition

An enum describing the relationship between a SCEV and a basic block.

Enumerator
DoesNotDominateBlock 

The SCEV does not dominate the block.

DominatesBlock 

The SCEV dominates the block.

ProperlyDominatesBlock 

The SCEV properly dominates the block.

Definition at line 455 of file ScalarEvolution.h.

◆ ExitCountKind

The terms "backedge taken count" and "exit count" are used interchangeably to refer to the number of times the backedge of a loop has executed before the loop is exited.

Enumerator
Exact 

An expression exactly describing the number of times the backedge has executed when a loop is exited.

ConstantMaximum 

A constant which provides an upper bound on the exact trip count.

SymbolicMaximum 

An expression which provides an upper bound on the exact trip count.

Definition at line 791 of file ScalarEvolution.h.

◆ LoopDisposition

An enum describing the relationship between a SCEV and a loop.

Enumerator
LoopVariant 

The SCEV is loop-variant (unknown).

LoopInvariant 

The SCEV is loop-invariant.

LoopComputable 

The SCEV varies predictably with the loop.

Definition at line 448 of file ScalarEvolution.h.

◆ MonotonicPredicateType

A predicate is said to be monotonically increasing if may go from being false to being true as the loop iterates, but never the other way around.

A predicate is said to be monotonically decreasing if may go from being true to being false as the loop iterates, but never the other way around.

Enumerator
MonotonicallyIncreasing 
MonotonicallyDecreasing 

Definition at line 1010 of file ScalarEvolution.h.

Constructor & Destructor Documentation

◆ ScalarEvolution() [1/2]

ScalarEvolution::ScalarEvolution ( Function F,
TargetLibraryInfo TLI,
AssumptionCache AC,
DominatorTree DT,
LoopInfo LI 
)

Definition at line 12687 of file ScalarEvolution.cpp.

References F, and llvm::Intrinsic::getName().

Referenced by willNotOverflow().

◆ ScalarEvolution() [2/2]

ScalarEvolution::ScalarEvolution ( ScalarEvolution &&  Arg)

Definition at line 12708 of file ScalarEvolution.cpp.

References Arg.

◆ ~ScalarEvolution()

ScalarEvolution::~ScalarEvolution ( )

Member Function Documentation

◆ applyLoopGuards()

const SCEV * ScalarEvolution::applyLoopGuards ( const SCEV Expr,
const Loop L 
)

◆ clearFlags()

static LLVM_NODISCARD SCEV::NoWrapFlags llvm::ScalarEvolution::clearFlags ( SCEV::NoWrapFlags  Flags,
SCEV::NoWrapFlags  OffFlags 
)
inlinestatic

Definition at line 472 of file ScalarEvolution.h.

◆ collectParametricTerms()

void ScalarEvolution::collectParametricTerms ( const SCEV Expr,
SmallVectorImpl< const SCEV * > &  Terms 
)

Collect parametric terms occurring in step expressions (first step of delinearization).

Find parametric terms in this SCEVAddRecExpr.

We first for parameters in two places: 1) The strides of AddRec expressions. 2) Unknowns that are multiplied with AddRec expressions.

Definition at line 12277 of file ScalarEvolution.cpp.

References llvm::dbgs(), LLVM_DEBUG, S, T, and llvm::visitAll().

Referenced by delinearize().

◆ computeAccessFunctions()

void ScalarEvolution::computeAccessFunctions ( const SCEV Expr,
SmallVectorImpl< const SCEV * > &  Subscripts,
SmallVectorImpl< const SCEV * > &  Sizes 
)

Return in Subscripts the access functions for each dimension in Sizes (third step of delinearization).

Definition at line 12460 of file ScalarEvolution.cpp.

References llvm::SmallVectorImpl< T >::clear(), llvm::dbgs(), llvm::SCEVDivision::divide(), i, llvm::SCEVAddRecExpr::isAffine(), LLVM_DEBUG, llvm::reverse(), and S.

Referenced by delinearize().

◆ computeConstantDifference()

Optional< APInt > ScalarEvolution::computeConstantDifference ( const SCEV LHS,
const SCEV RHS 
)

Compute LHS - RHS and returns the result as an APInt if it is a constant, and None if it isn't.

This is intended to be a cheaper version of getMinusSCEV. We can be frugal here since we just bail out of actually constructing and canonicalizing an expression in the cases where the result isn't going to be a constant.

Definition at line 10794 of file ScalarEvolution.cpp.

References C1, llvm::SCEV::getType(), getTypeSizeInBits(), llvm::CodeGenOpt::Less, M, and llvm::None.

◆ containsAddRecurrence()

bool ScalarEvolution::containsAddRecurrence ( const SCEV S)

◆ convertSCEVToAddRecWithPredicates()

const SCEVAddRecExpr * ScalarEvolution::convertSCEVToAddRecWithPredicates ( const SCEV S,
const Loop L,
SmallPtrSetImpl< const SCEVPredicate * > &  Preds 
)

Tries to convert the S expression to an AddRec expression, adding additional predicates to Preds as required.

Definition at line 13528 of file ScalarEvolution.cpp.

References llvm::SmallPtrSetImpl< PtrType >::insert(), P, rewrite(), and S.

Referenced by llvm::PredicatedScalarEvolution::getAsAddRec().

◆ createAddRecFromPHIWithCasts()

Optional< std::pair< const SCEV *, SmallVector< const SCEVPredicate *, 3 > > > ScalarEvolution::createAddRecFromPHIWithCasts ( const SCEVUnknown SymbolicPHI)

Checks if SymbolicPHI can be rewritten as an AddRecExpr under some Predicates.

If successful return these <AddRecExpr, Predicates>; The function is intended to be called from PSCEV (the caller will decide whether to actually add the predicates and carry out the rewrites).

Definition at line 5196 of file ScalarEvolution.cpp.

References assert(), llvm::SCEVUnknown::getValue(), I, isIntegerLoopHeaderPHI(), and llvm::None.

◆ delinearize()

void ScalarEvolution::delinearize ( const SCEV Expr,
SmallVectorImpl< const SCEV * > &  Subscripts,
SmallVectorImpl< const SCEV * > &  Sizes,
const SCEV ElementSize 
)

Split this SCEVAddRecExpr into two vectors of SCEVs representing the subscripts and sizes of an array access.

Splits the SCEV into two vectors of SCEVs representing the subscripts and sizes of an array access.

The delinearization is a 3 step process: the first two steps compute the sizes of each subscript and the third step computes the access functions for the delinearized array:

  1. Find the terms in the step functions
  2. Compute the array size
  3. Compute the access function: divide the SCEV by the array size starting with the innermost dimensions found in step 2. The Quotient is the SCEV to be divided in the next step of the recursion. The Remainder is the subscript of the innermost dimension. Loop over all array dimensions computed in step 2.

To compute a uniform array size for several memory accesses to the same object, one can collect in step 1 all the step terms for all the memory accesses, and compute in step 2 a unique array shape. This guarantees that the array shape will be the same across all memory accesses.

FIXME: We could derive the result of steps 1 and 2 from a description of the array shape given in metadata.

Example:

A[][n][m]

for i for j for k A[j+k][2i][5i] =

The initial SCEV:

A[{{{0,+,2*m+5}_i, +, n*m}_j, +, n*m}_k]

  1. Find the different terms in the step functions: -> [2*m, 5, n*m, n*m]
  2. Compute the array size: sort and unique them -> [n*m, 2*m, 5] find the GCD of all the terms = 1 divide by the GCD and erase constant terms -> [n*m, 2*m] GCD = m divide by GCD -> [n, 2] remove constant terms -> [n] size of the array is A[unknown][n][m]
  3. Compute the access function a. Divide {{{0,+,2*m+5}_i, +, n*m}_j, +, n*m}_k by the innermost size m Quotient: {{{0,+,2}_i, +, n}_j, +, n}_k Remainder: {{{0,+,5}_i, +, 0}_j, +, 0}_k The remainder is the subscript of the innermost array dimension: [5i].

b. Divide Quotient: {{{0,+,2}_i, +, n}_j, +, n}_k by next outer size n Quotient: {{{0,+,0}_i, +, 1}_j, +, 1}_k Remainder: {{{0,+,2}_i, +, 0}_j, +, 0}_k The Remainder is the subscript of the next array dimension: [2i].

The subscript of the outermost dimension is the Quotient: [j+k].

Overall, we have: A[][n][m], and the access function: A[j+k][2i][5i].

Returns the remainder of the delinearization that is the offset start of the array. The SCEV->delinearize algorithm computes the multiples of SCEV coefficients: that is a pattern matching of sub expressions in the stride and base of a SCEV corresponding to the computation of a GCD (greatest common divisor) of base and stride. When SCEV->delinearize fails, it returns the SCEV unchanged.

For example: when analyzing the memory access A[i][j][k] in this loop nest

void foo(long n, long m, long o, double A[n][m][o]) {

for (long i = 0; i < n; i++) for (long j = 0; j < m; j++) for (long k = 0; k < o; k++) A[i][j][k] = 1.0; }

the delinearization input is the following AddRec SCEV:

AddRec: {{{A,+,(8 * m * o)}<for.i>,+,(8 * o)}<for.j>,+,8}<for.k>

From this SCEV, we are able to say that the base offset of the access is A because it appears as an offset that does not divide any of the strides in the loops:

CHECK: Base offset: A

and then SCEV->delinearize determines the size of some of the dimensions of the array as these are the multiples by which the strides are happening:

CHECK: ArrayDecl[UnknownSize][m][o] with elements of sizeof(double) bytes.

Note that the outermost dimension remains of UnknownSize because there are no strides that would help identifying the size of the last dimension: when the array has been statically allocated, one could compute the size of that dimension by dividing the overall size of the array by the size of the known dimensions: m * o * 8.

Finally delinearize provides the access functions for the array reference that does correspond to A[i][j][k] of the above C testcase:

CHECK: ArrayRef[{0,+,1}<for.i>][{0,+,1}<for.j>][{0,+,1}<for.k>]

The testcases are checking the output of a function pass: DelinearizationPass that walks through all loads and stores of a function asking for the SCEV of the memory access with respect to all enclosing loops, calling SCEV->delinearize on that and printing the results.

Definition at line 12566 of file ScalarEvolution.cpp.

References collectParametricTerms(), computeAccessFunctions(), llvm::dbgs(), findArrayDimensions(), LLVM_DEBUG, and S.

◆ dominates()

bool ScalarEvolution::dominates ( const SCEV S,
const BasicBlock BB 
)

Return true if elements that makes up the given SCEV dominate the specified basic block.

Definition at line 13121 of file ScalarEvolution.cpp.

References BB, DominatesBlock, getBlockDisposition(), and S.

Referenced by llvm::isSafeToExpandAt().

◆ eraseValueFromMap()

void ScalarEvolution::eraseValueFromMap ( Value V)

Erase Value from ValueExprMap and ExprValueMap.

ValueExprMap.erase(V) cannot be used separately. eraseValueFromMap should be used to remove V from ValueExprMap and ExprValueMap at the same time.

Definition at line 4008 of file ScalarEvolution.cpp.

References llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::end(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::erase(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::find_as(), I, Offset, S, and splitAddExpr().

Referenced by forgetValue().

◆ evaluatePredicate()

Optional< bool > ScalarEvolution::evaluatePredicate ( ICmpInst::Predicate  Pred,
const SCEV LHS,
const SCEV RHS 
)

Check whether the condition described by Pred, LHS, and RHS is true or false.

If we know it, return the evaluation of this condition. If neither is proved, return None.

Definition at line 9902 of file ScalarEvolution.cpp.

References llvm::CmpInst::getInversePredicate(), isKnownPredicate(), and llvm::None.

Referenced by countToEliminateCompares(), and evaluatePredicateAt().

◆ evaluatePredicateAt()

Optional< bool > ScalarEvolution::evaluatePredicateAt ( ICmpInst::Predicate  Pred,
const SCEV LHS,
const SCEV RHS,
const Instruction Context 
)

Check whether the condition described by Pred, LHS, and RHS is true or false in the given Context.

If we know it, return the evaluation of this condition. If neither is proved, return None.

Definition at line 9921 of file ScalarEvolution.cpp.

References Context, evaluatePredicate(), llvm::CmpInst::getInversePredicate(), isBasicBlockEntryGuardedByCond(), and llvm::None.

◆ findArrayDimensions()

void ScalarEvolution::findArrayDimensions ( SmallVectorImpl< const SCEV * > &  Terms,
SmallVectorImpl< const SCEV * > &  Sizes,
const SCEV ElementSize 
)

Compute the array dimensions Sizes from the set of Terms extracted from the memory access function of this SCEVAddRecExpr (second step of delinearization).

Definition at line 12397 of file ScalarEvolution.cpp.

References llvm::array_pod_sort(), llvm::SmallVectorImpl< T >::clear(), containsParameters(), llvm::dbgs(), llvm::SCEVDivision::divide(), llvm::SmallVectorImpl< T >::erase(), findArrayDimensionsRec(), llvm::SCEV::isZero(), LLVM_DEBUG, numberOfTerms(), removeConstantFactors(), S, llvm::sort(), T, llvm::M68kBeads::Term, and llvm::unique().

Referenced by delinearize().

◆ forgetAllLoops()

void ScalarEvolution::forgetAllLoops ( )

◆ forgetLoop()

void ScalarEvolution::forgetLoop ( const Loop L)

This method should be called by the client when it has changed a loop in a way that may effect ScalarEvolution's ability to compute a trip count, or if the loop is deleted.

This call is potentially expensive for large loop bodies.

Definition at line 7440 of file ScalarEvolution.cpp.

References I, and llvm::SmallVectorImpl< T >::pop_back_val().

Referenced by llvm::breakLoopBackedge(), llvm::deleteDeadLoop(), deleteLoopIfDead(), DoFlattenLoopPair(), llvm::InnerLoopVectorizer::fixVectorizedLoop(), forgetTopmostLoop(), llvm::formLCSSA(), separateNestedLoop(), llvm::splitLoopBound(), llvm::UnrollAndJamLoop(), unswitchNontrivialInvariants(), unswitchTrivialBranch(), and unswitchTrivialSwitch().

◆ forgetLoopDispositions()

void ScalarEvolution::forgetLoopDispositions ( const Loop L)

Called when the client has changed the disposition of values in this loop.

We don't have a way to invalidate per-loop dispositions. Clear and recompute is simpler.

Definition at line 7530 of file ScalarEvolution.cpp.

Referenced by isLoopDead(), simplifyOneLoop(), and sinkLoopInvariantInstructions().

◆ forgetTopmostLoop()

void ScalarEvolution::forgetTopmostLoop ( const Loop L)

◆ forgetValue()

void ScalarEvolution::forgetValue ( Value V)

◆ getAbsExpr()

const SCEV * ScalarEvolution::getAbsExpr ( const SCEV Op,
bool  IsNSW 
)

◆ getAddExpr() [1/3]

const SCEV* llvm::ScalarEvolution::getAddExpr ( const SCEV LHS,
const SCEV RHS,
SCEV::NoWrapFlags  Flags = SCEV::FlagAnyWrap,
unsigned  Depth = 0 
)
inline

Definition at line 535 of file ScalarEvolution.h.

References llvm::Depth, and getAddExpr().

◆ getAddExpr() [2/3]

const SCEV* llvm::ScalarEvolution::getAddExpr ( const SCEV Op0,
const SCEV Op1,
const SCEV Op2,
SCEV::NoWrapFlags  Flags = SCEV::FlagAnyWrap,
unsigned  Depth = 0 
)
inline

Definition at line 541 of file ScalarEvolution.h.

References llvm::Depth, and getAddExpr().

◆ getAddExpr() [3/3]

const SCEV * ScalarEvolution::getAddExpr ( SmallVectorImpl< const SCEV * > &  Ops,
SCEV::NoWrapFlags  Flags = SCEV::FlagAnyWrap,
unsigned  Depth = 0 
)

Get a canonical add expression, or something simpler if possible.

Definition at line 2401 of file ScalarEvolution.cpp.

References llvm::APInt::abs(), AddOpsInlineThreshold, llvm::SmallVectorImpl< T >::append(), assert(), B, llvm::BitWidth, C1, llvm::SmallVectorImpl< T >::clear(), CollectAddOperandsWithScales(), llvm::count_if(), llvm::Depth, llvm::DominatorTree::dominates(), llvm::numbers::e, llvm::SmallVectorImpl< T >::erase(), f(), llvm::SCEV::FlagAnyWrap, llvm::SCEV::FlagNSW, llvm::SCEV::FlagNUW, llvm::SCEV::FlagNW, getAddRecExpr(), getAnyExtendExpr(), getConstant(), getEffectiveSCEVType(), llvm::LoopBase< BlockT, LoopT >::getHeader(), llvm::SCEVAddRecExpr::getLoop(), getMulExpr(), llvm::SCEVNAryExpr::getNoWrapFlags(), llvm::SCEVNAryExpr::getNumOperands(), getOne(), llvm::SCEVNAryExpr::getOperand(), llvm::SCEVAddRecExpr::getStart(), getTruncateExpr(), llvm::Intrinsic::getType(), getTypeSizeInBits(), getZero(), GroupByComplexity(), hasHugeExpression(), i, isAvailableAtLoopEntry(), llvm::APInt::isSignBitSet(), j(), M, maskFlags(), MaxArithDepth, llvm::Mul, llvm::SCEVNAryExpr::op_begin(), llvm::SCEVNAryExpr::op_end(), llvm::SCEVNAryExpr::operands(), S, llvm::scAddExpr, llvm::scAddRecExpr, llvm::scMulExpr, setFlags(), StrengthenNoWrapFlags(), T, llvm::APInt::ule(), and llvm::APInt::ult().

Referenced by applyLoopGuards(), llvm::calculateUpperBound(), llvm::LoopVectorizationCostModel::computeMaxVF(), countToEliminateCompares(), llvm::SCEVAddRecExpr::evaluateAtIteration(), ExposePointerBase(), ExtractImmediate(), ExtractSymbol(), FactorOutConstant(), genLoopLimit(), getAddExpr(), getExtendAddRecStart(), getGEPExpr(), getLosslessPtrToIntExpr(), getMinusSCEV(), getMulExpr(), getNewAlignment(), getNumBytes(), llvm::InnerLoopVectorizer::getOrCreateTripCount(), llvm::SCEVAddRecExpr::getPostIncExpr(), WidenIV::getSCEVByOpCode(), getSignExtendExpr(), getTripCountFromExitCount(), getTruncateExpr(), getUDivCeilSCEV(), getUDivExpr(), llvm::RuntimePointerChecking::insert(), llvm::HardwareLoopInfo::isHardwareLoopCandidate(), llvm::ARMTTIImpl::isHardwareLoopProfitable(), IsIncrementNSW(), IsIncrementNUW(), removePointerBase(), SimplifyAddOperands(), SimplifyICmpOperands(), llvm::UnrollRuntimeLoopRemainder(), llvm::SCEVDivision::visitAddExpr(), llvm::SCEVRewriteVisitor< SCEVLoopGuardRewriter >::visitAddExpr(), and willNotOverflow().

◆ getAddRecExpr() [1/3]

const SCEV * ScalarEvolution::getAddRecExpr ( const SCEV Start,
const SCEV Step,
const Loop L,
SCEV::NoWrapFlags  Flags 
)

◆ getAddRecExpr() [2/3]

const SCEV* llvm::ScalarEvolution::getAddRecExpr ( const SmallVectorImpl< const SCEV * > &  Operands,
const Loop L,
SCEV::NoWrapFlags  Flags 
)
inline

Definition at line 569 of file ScalarEvolution.h.

References getAddRecExpr(), and Operands.

◆ getAddRecExpr() [3/3]

const SCEV * ScalarEvolution::getAddRecExpr ( SmallVectorImpl< const SCEV * > &  Operands,
const Loop L,
SCEV::NoWrapFlags  Flags 
)

◆ getAnyExtendExpr()

const SCEV * ScalarEvolution::getAnyExtendExpr ( const SCEV Op,
Type Ty 
)

getAnyExtendExpr - Return a SCEV for the given operand extended with unspecified bits out to the given type.

Definition at line 2117 of file ScalarEvolution.cpp.

References assert(), llvm::SCEV::FlagNW, getAddRecExpr(), getEffectiveSCEVType(), getSignExtendExpr(), getTruncateOrNoop(), llvm::SCEV::getType(), getTypeSizeInBits(), getZeroExtendExpr(), isSCEVable(), llvm::PPCISD::SC, and T.

Referenced by getAddExpr(), and getNoopOrAnyExtend().

◆ getBackedgeTakenCount()

const SCEV * ScalarEvolution::getBackedgeTakenCount ( const Loop L,
ExitCountKind  Kind = Exact 
)

If the specified loop has a predictable backedge-taken count, return it, otherwise return a SCEVCouldNotCompute object.

The backedge-taken count is the number of times the loop header will be branched to from within the loop, assuming there are no abnormal exists like exception throws. This is one less than the trip count of the loop, since it doesn't count the first iteration, when the header is branched to from outside the loop.

Note that it is not valid to call this method on a loop without a loop-invariant backedge-taken count (see hasLoopInvariantBackedgeTakenCount).

Definition at line 7272 of file ScalarEvolution.cpp.

References ConstantMaximum, Exact, llvm_unreachable, and SymbolicMaximum.

Referenced by breakBackedgeIfNotTaken(), computeTripCount(), findLoopComponents(), getConstantMaxBackedgeTakenCount(), getSmallConstantTripCount(), getSymbolicMaxBackedgeTakenCount(), hasLoopInvariantBackedgeTakenCount(), llvm::ARMTTIImpl::isHardwareLoopProfitable(), llvm::IVUsers::print(), PrintLoopInfo(), and verify().

◆ getBlockDisposition()

ScalarEvolution::BlockDisposition ScalarEvolution::getBlockDisposition ( const SCEV S,
const BasicBlock BB 
)

Return the "disposition" of the given SCEV with respect to the given block.

Definition at line 13036 of file ScalarEvolution.cpp.

References BB, D, DoesNotDominateBlock, llvm::make_range(), and S.

Referenced by dominates(), and properlyDominates().

◆ getConstant() [1/3]

const SCEV * ScalarEvolution::getConstant ( const APInt Val)

Definition at line 457 of file ScalarEvolution.cpp.

References llvm::ConstantInt::get(), getConstant(), and getContext().

◆ getConstant() [2/3]

const SCEV * ScalarEvolution::getConstant ( ConstantInt V)

◆ getConstant() [3/3]

const SCEV * ScalarEvolution::getConstant ( Type Ty,
uint64_t  V,
bool  isSigned = false 
)

◆ getConstantMaxBackedgeTakenCount()

const SCEV* llvm::ScalarEvolution::getConstantMaxBackedgeTakenCount ( const Loop L)
inline

When successful, this returns a SCEVConstant that is greater than or equal to (i.e.

a "conservative over-approximation") of the value returend by getBackedgeTakenCount. If such a value cannot be computed, it returns the SCEVCouldNotCompute object.

Definition at line 833 of file ScalarEvolution.h.

References ConstantMaximum, and getBackedgeTakenCount().

Referenced by getSmallConstantMaxTripCount(), isLoopDead(), mustBeFiniteCountedLoop(), and PrintLoopInfo().

◆ getContext()

LLVMContext& llvm::ScalarEvolution::getContext ( ) const
inline

◆ getCouldNotCompute()

const SCEV * ScalarEvolution::getCouldNotCompute ( )

◆ getDataLayout()

const DataLayout& llvm::ScalarEvolution::getDataLayout ( ) const
inline

◆ getEffectiveSCEVType()

Type * ScalarEvolution::getEffectiveSCEVType ( Type Ty) const

Return a type with the same bitwidth as the given type and which represents how SCEV will treat the given type, for which isSCEVable must return true.

For pointer types, this is the pointer-sized integer type.

For pointer types, this is the pointer index sized integer type.

Definition at line 3931 of file ScalarEvolution.cpp.

References assert(), getDataLayout(), llvm::DataLayout::getIndexType(), llvm::Type::isIntegerTy(), llvm::Type::isPointerTy(), and isSCEVable().

Referenced by llvm::SCEVAAResult::alias(), canBeCheaplyTransformed(), WidenIV::createWideIV(), DoInitialMatch(), genLoopLimit(), getAddExpr(), getAddRecExpr(), getAnyExtendExpr(), getConstant(), getElementSize(), getGEPExpr(), getLosslessPtrToIntExpr(), getMinMaxExpr(), getNegativeSCEV(), getNewAlignment(), getNotSCEV(), getSignExtendExpr(), getTruncateExpr(), getURemExpr(), getZeroExtendExpr(), isExistingPhi(), and visitIVCast().

◆ getElementSize()

const SCEV * ScalarEvolution::getElementSize ( Instruction Inst)

Return the size of an element read or written by Inst.

Definition at line 12384 of file ScalarEvolution.cpp.

References getEffectiveSCEVType(), getSizeOfExpr(), llvm::PointerType::getUnqual(), llvm::SPII::Load, and llvm::SPII::Store.

◆ getEqualPredicate()

const SCEVPredicate * ScalarEvolution::getEqualPredicate ( const SCEV LHS,
const SCEV RHS 
)

◆ getExitCount()

const SCEV * ScalarEvolution::getExitCount ( const Loop L,
const BasicBlock ExitingBlock,
ExitCountKind  Kind = Exact 
)

Return the number of times the backedge executes before the given exit would be taken; if not exactly computable, return SCEVCouldNotCompute.

For a single exit loop, this value is equivelent to the result of getBackedgeTakenCount. The loop is guaranteed to exit (via some exit) before the backedge is executed (ExitCount + 1) times. Note that there is no guarantee about which exit is taken on the exiting iteration.

Definition at line 7253 of file ScalarEvolution.cpp.

References ConstantMaximum, Exact, llvm_unreachable, and SymbolicMaximum.

Referenced by llvm::calculateUpperBound(), getMinAnalyzeableBackedgeTakenCount(), getSmallConstantTripCount(), getSmallConstantTripMultiple(), llvm::hasIterationCountInvariantInParent(), llvm::HardwareLoopInfo::isHardwareLoopCandidate(), mustBeFiniteCountedLoop(), PrintLoopInfo(), llvm::rewriteLoopExitValues(), and llvm::UnrollRuntimeLoopRemainder().

◆ getGEPExpr()

const SCEV * ScalarEvolution::getGEPExpr ( GEPOperator GEP,
const SmallVectorImpl< const SCEV * > &  IndexExprs 
)

Returns an expression for a GEP.

GEP The GEP. The indices contained in the GEP itself are ignored, instead we use IndexExprs. IndexExprs The expressions for the indices.

Definition at line 3590 of file ScalarEvolution.cpp.

References assert(), llvm::SCEV::FlagAnyWrap, llvm::SCEV::FlagNSW, llvm::SCEV::FlagNUW, GEP, getAddExpr(), getEffectiveSCEVType(), getMulExpr(), getOffsetOfExpr(), getSCEV(), getSizeOfExpr(), getTruncateOrSignExtend(), llvm::SCEV::getType(), llvm::GetElementPtrInst::getTypeAtIndex(), Index, isKnownNonNegative(), and Offset.

◆ getIndexExpressionsFromGEP()

bool ScalarEvolution::getIndexExpressionsFromGEP ( const GetElementPtrInst GEP,
SmallVectorImpl< const SCEV * > &  Subscripts,
SmallVectorImpl< int > &  Sizes 
)

Gathers the individual index expressions from a GEP instruction.

This function optimistically assumes the GEP references into a fixed size array. If this is actually true, this function returns a list of array subscript expressions in Subscripts and a list of integers describing the size of the individual array dimensions in Sizes. Both lists have either equal length or the size list is one element shorter in case there is no known size available for the outermost array dimension. Returns true if successful and false otherwise.

Definition at line 12602 of file ScalarEvolution.cpp.

References assert(), llvm::SmallVectorImpl< T >::clear(), GEP, getSCEV(), and i.

◆ getLoopDisposition()

ScalarEvolution::LoopDisposition ScalarEvolution::getLoopDisposition ( const SCEV S,
const Loop L 
)

Return the "disposition" of the given SCEV with respect to the given loop.

Definition at line 12928 of file ScalarEvolution.cpp.

References D, LoopVariant, llvm::make_range(), and S.

Referenced by hasComputableLoopEvolution(), llvm::hasIterationCountInvariantInParent(), isLoopInvariant(), and print().

◆ getLoopInvariantExitCondDuringFirstIterations()

Optional< ScalarEvolution::LoopInvariantPredicate > ScalarEvolution::getLoopInvariantExitCondDuringFirstIterations ( ICmpInst::Predicate  Pred,
const SCEV LHS,
const SCEV RHS,
const Loop L,
const Instruction Context,
const SCEV MaxIter 
)

If the result of the predicate LHS Pred RHS is loop invariant with respect to L at given Context during at least first MaxIter iterations, return a LoopInvariantPredicate with LHS and RHS being invariants, available at L's entry.

Otherwise, return None. The predicate should be the loop's exit condition.

Definition at line 10058 of file ScalarEvolution.cpp.

References llvm::SCEVAddRecExpr::evaluateAtIteration(), llvm::SCEVAddRecExpr::getLoop(), getNegativeSCEV(), getOne(), llvm::SCEVAddRecExpr::getStepRecurrence(), llvm::CmpInst::getSwappedPredicate(), llvm::SCEV::getType(), llvm::SCEVAddRecExpr::getType(), llvm::CmpInst::ICMP_SLE, llvm::CmpInst::ICMP_ULE, isLoopBackedgeGuardedByCond(), isLoopInvariant(), llvm::ICmpInst::isRelational(), llvm::CmpInst::isSigned(), llvm::None, and std::swap().

Referenced by optimizeLoopExitWithUnknownExitCount().

◆ getLoopInvariantPredicate()

Optional< ScalarEvolution::LoopInvariantPredicate > ScalarEvolution::getLoopInvariantPredicate ( ICmpInst::Predicate  Pred,
const SCEV LHS,
const SCEV RHS,
const Loop L 
)

If the result of the predicate LHS Pred RHS is loop invariant with respect to L, return a LoopInvariantPredicate with LHS and RHS being invariants, available at L's entry.

Otherwise, return None.

Definition at line 10011 of file ScalarEvolution.cpp.

References llvm::CmpInst::getInversePredicate(), llvm::SCEVAddRecExpr::getLoop(), getMonotonicPredicateType(), llvm::SCEVAddRecExpr::getStart(), llvm::CmpInst::getSwappedPredicate(), isLoopBackedgeGuardedByCond(), isLoopInvariant(), MonotonicallyIncreasing, llvm::None, P, and std::swap().

◆ getLosslessPtrToIntExpr()

const SCEV * ScalarEvolution::getLosslessPtrToIntExpr ( const SCEV Op,
unsigned  Depth = 0 
)

The SCEVPtrToIntSinkingRewriter takes a scalar evolution expression, which computes a pointer-typed value, and rewrites the whole expression tree so that all the computations are done on integers, and the only pointer-typed operands in the expression are SCEVUnknown.

Definition at line 1052 of file ScalarEvolution.cpp.

References assert(), llvm::sampleprof::Base, llvm::Depth, getAddExpr(), getCouldNotCompute(), getDataLayout(), getEffectiveSCEVType(), llvm::DataLayout::getIntPtrType(), getLosslessPtrToIntExpr(), getMulExpr(), llvm::SCEVNAryExpr::getNoWrapFlags(), llvm::SCEV::getType(), llvm::SCEVUnknown::getType(), getTypeSizeInBits(), getZero(), llvm::Type::isIntegerTy(), llvm::Type::isPointerTy(), Operands, llvm::SCEVNAryExpr::operands(), rewrite(), Rewriter, S, and llvm::scPtrToInt.

Referenced by getLosslessPtrToIntExpr(), and getPtrToIntExpr().

◆ getMinMaxExpr()

const SCEV * ScalarEvolution::getMinMaxExpr ( SCEVTypes  Kind,
SmallVectorImpl< const SCEV * > &  Operands 
)

◆ GetMinTrailingZeros()

uint32_t ScalarEvolution::GetMinTrailingZeros ( const SCEV S)

Determine the minimum number of zero bits that S is guaranteed to end in (at every loop iteration).

It is, at the same time, the minimum number of times S is divisible by 2. For example, given {4,+,8} it returns 2. If S is guaranteed to be 0, it returns the bitwidth of S.

Definition at line 5833 of file ScalarEvolution.cpp.

References assert(), I, and S.

Referenced by extractConstantWithoutWrapping(), getSmallConstantTripMultiple(), getTruncateExpr(), and SolveLinEquationWithOverflow().

◆ getMinusOne()

const SCEV* llvm::ScalarEvolution::getMinusOne ( Type Ty)
inline

Return a SCEV for the constant -1 of a specific type.

Definition at line 610 of file ScalarEvolution.h.

References getConstant().

Referenced by getNegativeSCEV(), getNotSCEV(), and optimizeLoopExitWithUnknownExitCount().

◆ getMinusSCEV()

const SCEV * ScalarEvolution::getMinusSCEV ( const SCEV LHS,
const SCEV RHS,
SCEV::NoWrapFlags  Flags = SCEV::FlagAnyWrap,
unsigned  Depth = 0 
)

◆ getMonotonicPredicateType()

Optional< ScalarEvolution::MonotonicPredicateType > ScalarEvolution::getMonotonicPredicateType ( const SCEVAddRecExpr LHS,
ICmpInst::Predicate  Pred 
)

If, for all loop invariant X, the predicate "LHS `Pred` X" is monotonically increasing or decreasing, returns Some(MonotonicallyIncreasing) and Some(MonotonicallyDecreasing) respectively.

If we could not prove either of these facts, returns None.

Definition at line 9946 of file ScalarEvolution.cpp.

References assert(), and llvm::CmpInst::getSwappedPredicate().

Referenced by countToEliminateCompares(), and getLoopInvariantPredicate().

◆ getMulExpr() [1/3]

const SCEV* llvm::ScalarEvolution::getMulExpr ( const SCEV LHS,
const SCEV RHS,
SCEV::NoWrapFlags  Flags = SCEV::FlagAnyWrap,
unsigned  Depth = 0 
)
inline

Definition at line 550 of file ScalarEvolution.h.

References llvm::Depth, and getMulExpr().

◆ getMulExpr() [2/3]

const SCEV* llvm::ScalarEvolution::getMulExpr ( const SCEV Op0,
const SCEV Op1,
const SCEV Op2,
SCEV::NoWrapFlags  Flags = SCEV::FlagAnyWrap,
unsigned  Depth = 0 
)
inline

Definition at line 556 of file ScalarEvolution.h.

References llvm::Depth, and getMulExpr().

◆ getMulExpr() [3/3]

const SCEV * ScalarEvolution::getMulExpr ( SmallVectorImpl< const SCEV * > &  Ops,
SCEV::NoWrapFlags  Flags = SCEV::FlagAnyWrap,
unsigned  Depth = 0 
)

Get a canonical multiply expression, or something simpler if possible.

Definition at line 2971 of file ScalarEvolution.cpp.

References llvm::SmallVectorImpl< T >::append(), assert(), Choose(), containsConstantInAddMulChain(), llvm::Depth, llvm::numbers::e, llvm::SmallVectorImpl< T >::erase(), llvm::SCEV::FlagAnyWrap, llvm::SCEV::FlagNSW, llvm::SCEV::FlagNUW, llvm::SCEV::FlagNW, getAddExpr(), getAddRecExpr(), getConstant(), llvm::SCEVAddRecExpr::getLoop(), llvm::SCEVNAryExpr::getNoWrapFlags(), llvm::SCEVNAryExpr::getNumOperands(), llvm::SCEVNAryExpr::getOperand(), llvm::Intrinsic::getType(), llvm::SCEVAddRecExpr::getType(), getTypeSizeInBits(), getZero(), GroupByComplexity(), hasHugeExpression(), i, isAvailableAtLoopEntry(), llvm::Type::isPointerTy(), maskFlags(), llvm::max(), MaxAddRecSize, MaxArithDepth, llvm::min(), llvm::Mul, MulOpsInlineThreshold, Operands, llvm::SmallVectorImpl< T >::reserve(), S, llvm::scAddRecExpr, llvm::scMulExpr, StrengthenNoWrapFlags(), umul_ov(), x, y, and z.

Referenced by applyLoopGuards(), BinomialCoefficient(), CollectAddOperandsWithScales(), CollectSubexprs(), llvm::IndexedReference::computeRefCost(), DoInitialMatch(), llvm::SCEVAddRecExpr::evaluateAtIteration(), FactorOutConstant(), findArrayDimensionsRec(), getAddExpr(), getExactSDiv(), getGEPExpr(), getLosslessPtrToIntExpr(), getMulExpr(), getNegativeSCEV(), getNumBytes(), WidenIV::getSCEVByOpCode(), getTruncateExpr(), getUDivExactExpr(), getUDivExpr(), getURemExpr(), isSafeDependenceDistance(), removeConstantFactors(), SolveLinEquationWithOverflow(), llvm::SCEVDivision::visitMulExpr(), llvm::SCEVRewriteVisitor< SCEVLoopGuardRewriter >::visitMulExpr(), and willNotOverflow().

◆ getNegativeSCEV()

const SCEV * ScalarEvolution::getNegativeSCEV ( const SCEV V,
SCEV::NoWrapFlags  Flags = SCEV::FlagAnyWrap 
)

◆ getNoopOrAnyExtend()

const SCEV * ScalarEvolution::getNoopOrAnyExtend ( const SCEV V,
Type Ty 
)

Return a SCEV corresponding to a conversion of the input value to the specified type.

If the type must be extended, it is extended with unspecified bits. The conversion must not be narrowing.

Definition at line 4283 of file ScalarEvolution.cpp.

References assert(), getAnyExtendExpr(), llvm::SCEV::getType(), getTypeSizeInBits(), and llvm::Type::isIntOrPtrTy().

Referenced by llvm::IndexedReference::computeRefCost().

◆ getNoopOrSignExtend()

const SCEV * ScalarEvolution::getNoopOrSignExtend ( const SCEV V,
Type Ty 
)

Return a SCEV corresponding to a conversion of the input value to the specified type.

If the type must be extended, it is sign extended. The conversion must not be narrowing.

Definition at line 4271 of file ScalarEvolution.cpp.

References assert(), getSignExtendExpr(), llvm::SCEV::getType(), getTypeSizeInBits(), and llvm::Type::isIntOrPtrTy().

Referenced by getNewAlignment(), isSafeDependenceDistance(), and NoopOrExtend().

◆ getNoopOrZeroExtend()

const SCEV * ScalarEvolution::getNoopOrZeroExtend ( const SCEV V,
Type Ty 
)

Return a SCEV corresponding to a conversion of the input value to the specified type.

If the type must be extended, it is zero extended. The conversion must not be narrowing.

Definition at line 4259 of file ScalarEvolution.cpp.

References assert(), llvm::SCEV::getType(), getTypeSizeInBits(), getZeroExtendExpr(), and llvm::Type::isIntOrPtrTy().

Referenced by llvm::InnerLoopVectorizer::getOrCreateTripCount(), getUMaxFromMismatchedTypes(), getUMinFromMismatchedTypes(), and NoopOrExtend().

◆ getNotSCEV()

const SCEV * ScalarEvolution::getNotSCEV ( const SCEV V)

◆ getOffsetOfExpr()

const SCEV * ScalarEvolution::getOffsetOfExpr ( Type IntTy,
StructType STy,
unsigned  FieldNo 
)

Return an expression for offsetof on the given field with type IntTy.

Definition at line 3874 of file ScalarEvolution.cpp.

References getConstant(), and getDataLayout().

Referenced by getGEPExpr().

◆ getOne()

const SCEV* llvm::ScalarEvolution::getOne ( Type Ty)
inline

◆ getPointerBase()

const SCEV * ScalarEvolution::getPointerBase ( const SCEV V)

Transitively follow the chain of pointer-type operands until reaching a SCEV that does not have a single pointer operand.

This returns a SCEVUnknown pointer for well-formed pointer-type expressions, but corner cases do exist.

Definition at line 4350 of file ScalarEvolution.cpp.

References llvm::SCEV::getType(), and llvm::Type::isPointerTy().

Referenced by llvm::DependenceInfo::depends(), getMinusSCEV(), and isValidRewrite().

◆ getPredicatedBackedgeTakenCount()

const SCEV * ScalarEvolution::getPredicatedBackedgeTakenCount ( const Loop L,
SCEVUnionPredicate Predicates 
)

Similar to getBackedgeTakenCount, except it will add a set of SCEV predicates to Predicates that are required to be true in order for the answer to be correct.

Predicates can be checked with run-time checks and can be used to perform loop versioning.

Definition at line 7267 of file ScalarEvolution.cpp.

Referenced by llvm::PredicatedScalarEvolution::getBackedgeTakenCount(), and PrintLoopInfo().

◆ getPtrToIntExpr()

const SCEV * ScalarEvolution::getPtrToIntExpr ( const SCEV Op,
Type Ty 
)

◆ getSCEV()

const SCEV * ScalarEvolution::getSCEV ( Value V)

Return a SCEV expression for the full generality of the specified expression.

Return an existing SCEV if it exists, otherwise analyze the expression and create a new one.

Definition at line 4048 of file ScalarEvolution.cpp.

References assert(), llvm::Value::getType(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::insert(), isSCEVable(), Offset, S, SCEVCallbackVH, SCEVLostPoisonFlags(), and splitAddExpr().

Referenced by llvm::IVUsers::AddUsersImpl(), llvm::SCEVAAResult::alias(), llvm::analyzeICmp(), applyLoopGuards(), WidenIV::cloneArithmeticIVUser(), countToEliminateCompares(), WidenIV::createWideIV(), DbgGatherSalvagableDVI(), DbgRewriteSalvageableDVIs(), llvm::DependenceInfo::depends(), DoInitialMatch(), llvm::AlignmentFromAssumptionsPass::extractAlignmentInfo(), findIVOperand(), findLoopComponents(), FindLoopCounter(), genLoopLimit(), llvm::PredicatedScalarEvolution::getAsAddRec(), llvm::Loop::LoopBounds::getBounds(), getBoundsCheckCond(), WidenIV::getExtendedOperandRecurrence(), getFalkorUnrollingPreferences(), getGEPExpr(), getIndexExpressionsFromGEP(), getInductionVariable(), GetInductionVariable(), getNewAlignment(), llvm::getPointersDiff(), llvm::IVUsers::getReplacementExpr(), llvm::PredicatedScalarEvolution::getSCEV(), getSCEVAtScope(), llvm::DependenceInfo::getSplitIteration(), getStrengthenedNoWrapFlagsFromBinOp(), llvm::getStrideFromPointer(), WidenIV::getWideRecurrence(), llvm::isDereferenceableAndAlignedInLoop(), isExistingPhi(), isHighCostExpansion(), llvm::InductionDescriptor::isInductionPHI(), isLoopCounter(), isProfitableChain(), isSimpleIVUser(), llvm::LoopAccessInfo::isUniform(), isValidRewrite(), print(), llvm::PredicatedScalarEvolution::print(), llvm::AlignmentFromAssumptionsPass::processAssumption(), WidenIV::pushNarrowIVUsers(), llvm::replaceSymbolicStrideSCEV(), llvm::rewriteLoopExitValues(), llvm::splitLoopBound(), llvm::stripGetElementPtr(), WidenIV::widenIVUse(), and WidenIV::widenWithVariantUse().

◆ getSCEVAtScope() [1/2]

const SCEV * ScalarEvolution::getSCEVAtScope ( const SCEV S,
const Loop L 
)

Return a SCEV expression for the specified value at the specified scope in the program.

The L value specifies a loop nest to evaluate the expression at, where null is the top-level or a specified loop is immediately inside of the loop.

This method can be used to compute the exit value for a variable defined in a loop by querying what the value will hold in the parent loop.

In the case that a relevant loop exit value cannot be computed, the original value V is returned.

Definition at line 8709 of file ScalarEvolution.cpp.

References llvm::AArch64CC::LS, and llvm::reverse().

Referenced by computeUnrollAndJamCount(), getSCEVAtScope(), isInteresting(), optimizeLoopExitWithUnknownExitCount(), print(), and llvm::rewriteLoopExitValues().

◆ getSCEVAtScope() [2/2]

const SCEV * ScalarEvolution::getSCEVAtScope ( Value V,
const Loop L 
)

This is a convenience function which does getSCEVAtScope(getSCEV(V), L).

Definition at line 9077 of file ScalarEvolution.cpp.

References getSCEV(), and getSCEVAtScope().

◆ getSignedRange()

ConstantRange llvm::ScalarEvolution::getSignedRange ( const SCEV S)
inline

Determine the signed range for a particular SCEV.

NOTE: This returns a copy of the reference returned by getRangeRef.

Definition at line 908 of file ScalarEvolution.h.

References S.

Referenced by getSignExtendExpr(), print(), and StrengthenNoWrapFlags().

◆ getSignedRangeMax()

APInt llvm::ScalarEvolution::getSignedRangeMax ( const SCEV S)
inline

Determine the max of the signed range for a particular SCEV.

Definition at line 918 of file ScalarEvolution.h.

References llvm::ConstantRange::getSignedMax(), and S.

Referenced by getSignedOverflowLimitForStep(), isKnownNegative(), isKnownNonPositive(), and SimplifyICmpOperands().

◆ getSignedRangeMin()

APInt llvm::ScalarEvolution::getSignedRangeMin ( const SCEV S)
inline

Determine the min of the signed range for a particular SCEV.

Definition at line 913 of file ScalarEvolution.h.

References llvm::ConstantRange::getSignedMin(), and S.

Referenced by getMinusSCEV(), getSignedOverflowLimitForStep(), isKnownNonNegative(), isKnownPositive(), and SimplifyICmpOperands().

◆ getSignExtendExpr()

const SCEV * ScalarEvolution::getSignExtendExpr ( const SCEV Op,
Type Ty,
unsigned  Depth = 0 
)

◆ getSizeOfExpr()

const SCEV * ScalarEvolution::getSizeOfExpr ( Type IntTy,
Type AllocTy 
)

Return an expression for the alloc size of AllocTy that is type IntTy.

Definition at line 3856 of file ScalarEvolution.cpp.

References getConstant(), getDataLayout(), and getSizeOfScalableVectorExpr().

Referenced by genLoopLimit(), getElementSize(), and getGEPExpr().

◆ getSizeOfScalableVectorExpr()

const SCEV * ScalarEvolution::getSizeOfScalableVectorExpr ( Type IntTy,
ScalableVectorType ScalableTy 
)

Return an expression for sizeof ScalableTy that is type IntTy, where ScalableTy is a scalable vector type.

Definition at line 3845 of file ScalarEvolution.cpp.

References GEP, llvm::ConstantInt::get(), llvm::ConstantExpr::getGetElementPtr(), llvm::Constant::getNullValue(), llvm::Type::getPointerTo(), llvm::ConstantExpr::getPtrToInt(), and getUnknown().

Referenced by getSizeOfExpr(), and getStoreSizeOfExpr().

◆ getSmallConstantMaxTripCount()

unsigned ScalarEvolution::getSmallConstantMaxTripCount ( const Loop L)

Returns the upper bound of the loop trip count as a normal unsigned value.

Returns 0 if the trip count is unknown or not constant.

Definition at line 7183 of file ScalarEvolution.cpp.

References getConstantMaxBackedgeTakenCount(), and getConstantTripCount().

Referenced by llvm::HexagonTTIImpl::getPeelingPreferences(), getSmallBestKnownTC(), llvm::isDereferenceableAndAlignedInLoop(), llvm::LoopVectorizationCostModel::isMoreProfitable(), mayContainUnboundedCycle(), tryToUnrollLoop(), and llvm::UnrollLoop().

◆ getSmallConstantTripCount() [1/2]

unsigned ScalarEvolution::getSmallConstantTripCount ( const Loop L)

Returns the exact trip count of the loop if we can compute it, and the result is a small constant.

'0' is used to represent an unknown or non-constant trip count. Note that a trip count is simply one more than the backedge taken count for the loop.

Definition at line 7167 of file ScalarEvolution.cpp.

References Exact, getBackedgeTakenCount(), and getConstantTripCount().

Referenced by llvm::CacheCost::CacheCost(), llvm::LoopVectorizationCostModel::computeMaxVF(), llvm::HexagonTTIImpl::getPeelingPreferences(), getSmallBestKnownTC(), llvm::PPCTTIImpl::isHardwareLoopProfitable(), tryToUnrollAndJamLoop(), tryToUnrollLoop(), and llvm::UnrollLoop().

◆ getSmallConstantTripCount() [2/2]

unsigned ScalarEvolution::getSmallConstantTripCount ( const Loop L,
const BasicBlock ExitingBlock 
)

Return the exact trip count for this loop if we exit through ExitingBlock.

'0' is used to represent an unknown or non-constant trip count. Note that a trip count is simply one more than the backedge taken count for the same exit. This "trip count" assumes that control exits via ExitingBlock. More precisely, it is the number of times that control will reach ExitingBlock before taking the branch. For loops with multiple exits, it may not be the number times that the loop header executes if the loop exits prematurely via another branch.

Definition at line 7173 of file ScalarEvolution.cpp.

References assert(), getConstantTripCount(), getExitCount(), and llvm::LoopBase< BlockT, LoopT >::isLoopExiting().

◆ getSmallConstantTripMultiple() [1/3]

unsigned ScalarEvolution::getSmallConstantTripMultiple ( const Loop L)

Returns the largest constant divisor of the trip count of the loop.

Will return 1 if no trip count could be computed, or if a divisor could not be found.

Definition at line 7189 of file ScalarEvolution.cpp.

References llvm::LoopBase< BlockT, LoopT >::getExitingBlocks(), getSmallConstantTripMultiple(), llvm::Optional< T >::getValueOr(), llvm::GreatestCommonDivisor64(), and llvm::None.

◆ getSmallConstantTripMultiple() [2/3]

unsigned ScalarEvolution::getSmallConstantTripMultiple ( const Loop L,
const BasicBlock ExitingBlock 
)

Returns the largest constant divisor of the trip count of this loop as a normal unsigned value, if possible.

This means that the actual trip count is always a multiple of the returned value (don't forget the trip count could very well be zero as well!). As explained in the comments for getSmallConstantTripCount, this assumes that control exits the loop via ExitingBlock.

This means that the actual trip count is always a multiple of the returned value (don't forget the trip count could very well be zero as well!).

Returns 1 if the trip count is unknown or not guaranteed to be the multiple of a constant (which is also the case if the trip count is simply constant, use getSmallConstantTripCount for that case), Will also return 1 if the trip count is very large (>= 2^32).

As explained in the comments for getSmallConstantTripCount, this assumes that control exits the loop via ExitingBlock.

Definition at line 7244 of file ScalarEvolution.cpp.

References assert(), getExitCount(), getSmallConstantTripMultiple(), and llvm::LoopBase< BlockT, LoopT >::isLoopExiting().

◆ getSmallConstantTripMultiple() [3/3]

unsigned ScalarEvolution::getSmallConstantTripMultiple ( const Loop L,
const SCEV ExitCount 
)

Returns the largest constant divisor of the trip count as a normal unsigned value, if possible.

This means that the actual trip count is always a multiple of the returned value. Returns 1 if the trip count is unknown or not guaranteed to be the multiple of a constant., Will also return 1 if the trip count is very large (>= 2^32). Note that the argument is an exit count for loop L, NOT a trip count.

Definition at line 7203 of file ScalarEvolution.cpp.

References applyLoopGuards(), getCouldNotCompute(), GetMinTrailingZeros(), getTripCountFromExitCount(), llvm::SCEVConstant::getValue(), and llvm::min().

Referenced by getSmallConstantTripMultiple(), PrintLoopInfo(), tryToUnrollAndJamLoop(), tryToUnrollLoop(), and llvm::UnrollLoop().

◆ getSMaxExpr() [1/2]

const SCEV * ScalarEvolution::getSMaxExpr ( const SCEV LHS,
const SCEV RHS 
)

◆ getSMaxExpr() [2/2]

const SCEV * ScalarEvolution::getSMaxExpr ( SmallVectorImpl< const SCEV * > &  Operands)

Definition at line 3811 of file ScalarEvolution.cpp.

References getMinMaxExpr(), and llvm::scSMaxExpr.

◆ getSMinExpr() [1/2]

const SCEV * ScalarEvolution::getSMinExpr ( const SCEV LHS,
const SCEV RHS 
)

◆ getSMinExpr() [2/2]

const SCEV * ScalarEvolution::getSMinExpr ( SmallVectorImpl< const SCEV * > &  Operands)

Definition at line 3830 of file ScalarEvolution.cpp.

References getMinMaxExpr(), and llvm::scSMinExpr.

◆ getStoreSizeOfExpr()

const SCEV * ScalarEvolution::getStoreSizeOfExpr ( Type IntTy,
Type StoreTy 
)

Return an expression for the store size of StoreTy that is type IntTy.

Definition at line 3865 of file ScalarEvolution.cpp.

References getConstant(), getDataLayout(), and getSizeOfScalableVectorExpr().

Referenced by llvm::RuntimePointerChecking::insert().

◆ getStrengthenedNoWrapFlagsFromBinOp()

std::pair< SCEV::NoWrapFlags, bool > ScalarEvolution::getStrengthenedNoWrapFlagsFromBinOp ( const OverflowingBinaryOperator OBO)

Parse NSW/NUW flags from add/sub/mul IR binary operation Op into SCEV no-wrap flags, and deduce flag[s] that aren't known yet.

Does not mutate the original instruction.

Definition at line 2289 of file ScalarEvolution.cpp.

References llvm::MCID::Add, llvm::SCEV::FlagNSW, llvm::SCEV::FlagNUW, llvm::Operator::getOpcode(), llvm::User::getOperand(), getSCEV(), llvm::OverflowingBinaryOperator::hasNoSignedWrap(), llvm::OverflowingBinaryOperator::hasNoUnsignedWrap(), setFlags(), and willNotOverflow().

◆ getSymbolicMaxBackedgeTakenCount()

const SCEV* llvm::ScalarEvolution::getSymbolicMaxBackedgeTakenCount ( const Loop L)
inline

When successful, this returns a SCEV that is greater than or equal to (i.e.

a "conservative over-approximation") of the value returend by getBackedgeTakenCount. If such a value cannot be computed, it returns the SCEVCouldNotCompute object.

Definition at line 841 of file ScalarEvolution.h.

References getBackedgeTakenCount(), and SymbolicMaximum.

◆ getTripCountFromExitCount()

const SCEV * ScalarEvolution::getTripCountFromExitCount ( const SCEV ExitCount)

Convert from an "exit count" (i.e.

"backedge taken count") to a "trip count". A "trip count" is the number of times the header of the loop will execute if an exit is taken after the specified number of backedges have been taken. (e.g. TripCount = ExitCount + 1) A zero result must be interpreted as a loop having an unknown trip count.

Definition at line 7147 of file ScalarEvolution.cpp.

References getAddExpr(), getOne(), and llvm::SCEV::getType().

Referenced by computeTripCount(), findLoopComponents(), and getSmallConstantTripMultiple().

◆ getTruncateExpr()

const SCEV * ScalarEvolution::getTruncateExpr ( const SCEV Op,
Type Ty,
unsigned  Depth = 0 
)

◆ getTruncateOrNoop()

const SCEV * ScalarEvolution::getTruncateOrNoop ( const SCEV V,
Type Ty 
)

Return a SCEV corresponding to a conversion of the input value to the specified type.

The conversion must not be widening.

Definition at line 4295 of file ScalarEvolution.cpp.

References assert(), getTruncateExpr(), llvm::SCEV::getType(), getTypeSizeInBits(), and llvm::Type::isIntOrPtrTy().

Referenced by canBeCheaplyTransformed(), getAnyExtendExpr(), and llvm::InnerLoopVectorizer::getOrCreateTripCount().

◆ getTruncateOrSignExtend()

const SCEV * ScalarEvolution::getTruncateOrSignExtend ( const SCEV V,
Type Ty,
unsigned  Depth = 0 
)

Return a SCEV corresponding to a conversion of the input value to the specified type.

If the type must be extended, it is sign extended.

Definition at line 4246 of file ScalarEvolution.cpp.

References assert(), llvm::Depth, getSignExtendExpr(), getTruncateExpr(), llvm::SCEV::getType(), getTypeSizeInBits(), and llvm::Type::isIntOrPtrTy().

Referenced by getGEPExpr(), getSignExtendExpr(), and getTruncateExpr().

◆ getTruncateOrZeroExtend()

const SCEV * ScalarEvolution::getTruncateOrZeroExtend ( const SCEV V,
Type Ty,
unsigned  Depth = 0 
)

Return a SCEV corresponding to a conversion of the input value to the specified type.

If the type must be extended, it is zero extended.

Definition at line 4234 of file ScalarEvolution.cpp.

References assert(), llvm::Depth, getTruncateExpr(), llvm::SCEV::getType(), getTypeSizeInBits(), getZeroExtendExpr(), and llvm::Type::isIntOrPtrTy().

Referenced by BinomialCoefficient(), llvm::AlignmentFromAssumptionsPass::extractAlignmentInfo(), genLoopLimit(), getNewAlignment(), getNumBytes(), getPtrToIntExpr(), getTruncateExpr(), and getZeroExtendExpr().

◆ getTypeSizeInBits()

uint64_t ScalarEvolution::getTypeSizeInBits ( Type Ty) const

◆ getUDivCeilSCEV()

const SCEV * ScalarEvolution::getUDivCeilSCEV ( const SCEV N,
const SCEV D 
)

Compute ceil(N / D).

N and D are treated as unsigned values.

Since SCEV doesn't have native ceiling division, this generates a SCEV expression of the following form:

umin(N, 1) + floor((N - umin(N, 1)) / D)

A denominator of zero or poison is handled the same way as getUDivExpr().

Definition at line 11518 of file ScalarEvolution.cpp.

References D, getAddExpr(), getMinusSCEV(), getOne(), getUDivExpr(), getUMinExpr(), and N.

◆ getUDivExactExpr()

const SCEV * ScalarEvolution::getUDivExactExpr ( const SCEV LHS,
const SCEV RHS 
)

Get a canonical unsigned division expression, or something simpler if possible.

There is no representation for an exact udiv in SCEV IR, but we can attempt to remove factors from the LHS and RHS. We can't do this when it's not exact because the udiv may be clearing bits.

Definition at line 3441 of file ScalarEvolution.cpp.

References llvm::drop_begin(), llvm::numbers::e, gcd(), getConstant(), getMulExpr(), getUDivExpr(), i, llvm::APInt::isIntN(), llvm::Mul, and Operands.

Referenced by SolveLinEquationWithOverflow().

◆ getUDivExpr()

const SCEV * ScalarEvolution::getUDivExpr ( const SCEV LHS,
const SCEV RHS 
)

◆ getUMaxExpr() [1/2]

const SCEV * ScalarEvolution::getUMaxExpr ( const SCEV LHS,
const SCEV RHS 
)

◆ getUMaxExpr() [2/2]

const SCEV * ScalarEvolution::getUMaxExpr ( SmallVectorImpl< const SCEV * > &  Operands)

Definition at line 3820 of file ScalarEvolution.cpp.

References getMinMaxExpr(), and llvm::scUMaxExpr.

◆ getUMaxFromMismatchedTypes()

const SCEV * ScalarEvolution::getUMaxFromMismatchedTypes ( const SCEV LHS,
const SCEV RHS 
)

Promote the operands to the wider of the types using zero-extension, and then perform a umax operation with them.

Definition at line 4306 of file ScalarEvolution.cpp.

References getNoopOrZeroExtend(), llvm::SCEV::getType(), getTypeSizeInBits(), getUMaxExpr(), and getZeroExtendExpr().

◆ getUMinExpr() [1/2]

const SCEV * ScalarEvolution::getUMinExpr ( const SCEV LHS,
const SCEV RHS 
)

◆ getUMinExpr() [2/2]

const SCEV * ScalarEvolution::getUMinExpr ( SmallVectorImpl< const SCEV * > &  Operands)

Definition at line 3840 of file ScalarEvolution.cpp.

References getMinMaxExpr(), and llvm::scUMinExpr.

◆ getUMinFromMismatchedTypes() [1/2]

const SCEV * ScalarEvolution::getUMinFromMismatchedTypes ( const SCEV LHS,
const SCEV RHS 
)

Promote the operands to the wider of the types using zero-extension, and then perform a umin operation with them.

Definition at line 4319 of file ScalarEvolution.cpp.

Referenced by getMinAnalyzeableBackedgeTakenCount().

◆ getUMinFromMismatchedTypes() [2/2]

const SCEV * ScalarEvolution::getUMinFromMismatchedTypes ( SmallVectorImpl< const SCEV * > &  Ops)

Promote the operands to the wider of the types using zero-extension, and then perform a umin operation with them.

N-ary function.

Definition at line 4325 of file ScalarEvolution.cpp.

References assert(), getNoopOrZeroExtend(), getUMinExpr(), getWiderType(), and S.

◆ getUnknown()

const SCEV * ScalarEvolution::getUnknown ( Value V)

◆ getUnsignedRange()

ConstantRange llvm::ScalarEvolution::getUnsignedRange ( const SCEV S)
inline

Determine the unsigned range for a particular SCEV.

NOTE: This returns a copy of the reference returned by getRangeRef.

Definition at line 892 of file ScalarEvolution.h.

References S.

Referenced by llvm::SCEVAAResult::alias(), getBoundsCheckCond(), getZeroExtendExpr(), mustBeFiniteCountedLoop(), print(), and StrengthenNoWrapFlags().

◆ getUnsignedRangeMax()

APInt llvm::ScalarEvolution::getUnsignedRangeMax ( const SCEV S)
inline

Determine the max of the unsigned range for a particular SCEV.

Definition at line 902 of file ScalarEvolution.h.

References llvm::ConstantRange::getUnsignedMax(), and S.

Referenced by getUnsignedOverflowLimitForStep(), llvm::ARMTTIImpl::isHardwareLoopProfitable(), and SimplifyICmpOperands().

◆ getUnsignedRangeMin()

APInt llvm::ScalarEvolution::getUnsignedRangeMin ( const SCEV S)
inline

Determine the min of the unsigned range for a particular SCEV.

Definition at line 897 of file ScalarEvolution.h.

References llvm::ConstantRange::getUnsignedMin(), and S.

Referenced by isKnownNonZero(), and SimplifyICmpOperands().

◆ getURemExpr()

const SCEV * ScalarEvolution::getURemExpr ( const SCEV LHS,
const SCEV RHS 
)

◆ getWiderType()

Type * ScalarEvolution::getWiderType ( Type Ty1,
Type Ty2 
) const

◆ getWrapPredicate()

const SCEVPredicate * ScalarEvolution::getWrapPredicate ( const SCEVAddRecExpr AR,
SCEVWrapPredicate::IncrementWrapFlags  AddedFlags 
)

◆ getZero()

const SCEV* llvm::ScalarEvolution::getZero ( Type Ty)
inline

◆ getZeroExtendExpr()

const SCEV * ScalarEvolution::getZeroExtendExpr ( const SCEV Op,
Type Ty,
unsigned  Depth = 0 
)

◆ hasComputableLoopEvolution()

bool ScalarEvolution::hasComputableLoopEvolution ( const SCEV S,
const Loop L 
)

Return true if the given SCEV changes value in a known way in the specified loop.

This property being true implies that the value is variant in the loop AND that we can emit an expression to compute the value of the expression at any particular loop iteration.

Definition at line 13031 of file ScalarEvolution.cpp.

References getLoopDisposition(), LoopComputable, and S.

◆ hasLoopInvariantBackedgeTakenCount()

bool ScalarEvolution::hasLoopInvariantBackedgeTakenCount ( const Loop L)

Return true if the specified loop has an analyzable loop-invariant backedge-taken count.

Definition at line 12759 of file ScalarEvolution.cpp.

References getBackedgeTakenCount().

Referenced by llvm::ARMTTIImpl::isHardwareLoopProfitable(), llvm::IVUsers::print(), and PrintLoopInfo().

◆ hasOperand()

bool ScalarEvolution::hasOperand ( const SCEV S,
const SCEV Op 
) const

Test whether the given SCEV has Op as a direct or indirect operand.

Definition at line 13129 of file ScalarEvolution.cpp.

References S, and llvm::SCEVExprContains().

◆ invalidate()

bool ScalarEvolution::invalidate ( Function F,
const PreservedAnalyses PA,
FunctionAnalysisManager::Invalidator Inv 
)

◆ isAvailableAtLoopEntry()

bool ScalarEvolution::isAvailableAtLoopEntry ( const SCEV S,
const Loop L 
)

Determine if the SCEV can be evaluated at loop's entry.

It is true if it doesn't depend on a SCEVUnknown of an instruction which is dominated by the header of loop L.

Definition at line 2396 of file ScalarEvolution.cpp.

References llvm::LoopBase< BlockT, LoopT >::getHeader(), isLoopInvariant(), properlyDominates(), and S.

Referenced by llvm::cannotBeMaxInLoop(), llvm::cannotBeMinInLoop(), getAddExpr(), getMulExpr(), llvm::hasProcessableCondition(), llvm::isKnownNegativeInLoop(), llvm::isKnownNonNegativeInLoop(), isKnownViaInduction(), and isLoopEntryGuardedByCond().

◆ isBackedgeTakenCountMaxOrZero()

bool ScalarEvolution::isBackedgeTakenCountMaxOrZero ( const Loop L)

Return true if the backedge taken count is either the value returned by getConstantMaxBackedgeTakenCount or zero.

Definition at line 7285 of file ScalarEvolution.cpp.

Referenced by PrintLoopInfo(), tryToUnrollLoop(), and llvm::UnrollLoop().

◆ isBasicBlockEntryGuardedByCond()

bool ScalarEvolution::isBasicBlockEntryGuardedByCond ( const BasicBlock BB,
ICmpInst::Predicate  Pred,
const SCEV LHS,
const SCEV RHS 
)

◆ isKnownNegative()

bool ScalarEvolution::isKnownNegative ( const SCEV S)

Test if the given expression is known to be negative.

Definition at line 9804 of file ScalarEvolution.cpp.

References getSignedRangeMax(), llvm::APInt::isNegative(), and S.

Referenced by llvm::IndexedReference::computeRefCost(), getSignedOverflowLimitForStep(), and WidenIV::widenWithVariantUse().

◆ isKnownNonNegative()

bool ScalarEvolution::isKnownNonNegative ( const SCEV S)

Test if the given expression is known to be non-negative.

Definition at line 9812 of file ScalarEvolution.cpp.

References getSignedRangeMin(), llvm::APInt::isNegative(), and S.

Referenced by getGEPExpr(), getMinusSCEV(), and StrengthenNoWrapFlags().

◆ isKnownNonPositive()

bool ScalarEvolution::isKnownNonPositive ( const SCEV S)

Test if the given expression is known to be non-positive.

Definition at line 9816 of file ScalarEvolution.cpp.

References getSignedRangeMax(), llvm::APInt::isStrictlyPositive(), and S.

◆ isKnownNonZero()

bool ScalarEvolution::isKnownNonZero ( const SCEV S)

Test if the given expression is known to be non-zero.

Definition at line 9820 of file ScalarEvolution.cpp.

References getUnsignedRangeMin(), and S.

Referenced by breakBackedgeIfNotTaken().

◆ isKnownOnEveryIteration()

bool ScalarEvolution::isKnownOnEveryIteration ( ICmpInst::Predicate  Pred,
const SCEVAddRecExpr LHS,
const SCEV RHS 
)

Test if the condition described by Pred, LHS, RHS is known to be true on every iteration of the loop of the recurrency LHS.

Definition at line 9937 of file ScalarEvolution.cpp.

References llvm::SCEVAddRecExpr::getLoop(), llvm::SCEVAddRecExpr::getPostIncExpr(), llvm::SCEVAddRecExpr::getStart(), isLoopBackedgeGuardedByCond(), and isLoopEntryGuardedByCond().

◆ isKnownPositive()

bool ScalarEvolution::isKnownPositive ( const SCEV S)

Test if the given expression is known to be positive.

Definition at line 9808 of file ScalarEvolution.cpp.

References getSignedRangeMin(), llvm::APInt::isStrictlyPositive(), and S.

Referenced by getSignedOverflowLimitForStep(), and isSafeDependenceDistance().

◆ isKnownPredicate()

bool ScalarEvolution::isKnownPredicate ( ICmpInst::Predicate  Pred,
const SCEV LHS,
const SCEV RHS 
)

Test if the given expression is known to satisfy the condition described by Pred, LHS, and RHS.

Definition at line 9887 of file ScalarEvolution.cpp.

References isKnownViaInduction(), and SimplifyICmpOperands().

Referenced by llvm::calculateUpperBound(), countToEliminateCompares(), evaluatePredicate(), isKnownPredicateAt(), IsKnownPredicateViaAddRecStart(), normalizePredicate(), and WidenIV::pushNarrowIVUsers().

◆ isKnownPredicateAt()

bool ScalarEvolution::isKnownPredicateAt ( ICmpInst::Predicate  Pred,
const SCEV LHS,
const SCEV RHS,
const Instruction Context 
)

Test if the given expression is known to satisfy the condition described by Pred, LHS, and RHS in the given Context.

Definition at line 9912 of file ScalarEvolution.cpp.

References Context, isBasicBlockEntryGuardedByCond(), and isKnownPredicate().

Referenced by optimizeLoopExitWithUnknownExitCount(), and WidenIV::widenWithVariantUse().

◆ isKnownViaInduction()

bool ScalarEvolution::isKnownViaInduction ( ICmpInst::Predicate  Pred,
const SCEV LHS,
const SCEV RHS 
)

We'd like to check the predicate on every iteration of the most dominated loop between loops used in LHS and RHS.

To do this we use the following list of steps:

  1. Collect set S all loops on which either LHS or RHS depend.
  2. If S is non-empty a. Let PD be the element of S which is dominated by all other elements. b. Let E(LHS) be value of LHS on entry of PD. To get E(LHS), we should just take LHS and replace all AddRecs that are attached to PD on with their entry values. Define E(RHS) in the same way. c. Let B(LHS) be value of L on backedge of PD. To get B(LHS), we should just take LHS and replace all AddRecs that are attached to PD on with their backedge values. Define B(RHS) in the same way. d. Note that E(LHS) and E(RHS) are automatically available on entry of PD, so we can assert on that. e. Return true if isLoopEntryGuardedByCond(Pred, E(LHS), E(RHS)) && isLoopBackedgeGuardedByCond(Pred, B(LHS), B(RHS))

Definition at line 9836 of file ScalarEvolution.cpp.

References assert(), llvm::DominatorTree::dominates(), llvm::SmallPtrSetImplBase::empty(), getCouldNotCompute(), isAvailableAtLoopEntry(), isLoopBackedgeGuardedByCond(), isLoopEntryGuardedByCond(), L2, and SplitIntoInitAndPostInc().

Referenced by isKnownPredicate().

◆ isLoopBackedgeGuardedByCond()

bool ScalarEvolution::isLoopBackedgeGuardedByCond ( const Loop L,
ICmpInst::Predicate  Pred,
const SCEV LHS,
const SCEV RHS 
)

◆ isLoopEntryGuardedByCond()

bool ScalarEvolution::isLoopEntryGuardedByCond ( const Loop L,
ICmpInst::Predicate  Pred,
const SCEV LHS,
const SCEV RHS 
)

Test whether entry to the loop is protected by a conditional between LHS and RHS.

This is used to help avoid max expressions in loop trip counts, and to eliminate casts.

Definition at line 10504 of file ScalarEvolution.cpp.

References assert(), llvm::LoopBase< BlockT, LoopT >::getHeader(), isAvailableAtLoopEntry(), and isBasicBlockEntryGuardedByCond().

Referenced by llvm::cannotBeMaxInLoop(), llvm::cannotBeMinInLoop(), getNumBytes(), llvm::isKnownNegativeInLoop(), llvm::isKnownNonNegativeInLoop(), isKnownOnEveryIteration(), and isKnownViaInduction().

◆ isLoopInvariant()

bool ScalarEvolution::isLoopInvariant ( const SCEV S,
const Loop L 
)

◆ isSCEVable()

bool ScalarEvolution::isSCEVable ( Type Ty) const

◆ maskFlags()

static LLVM_NODISCARD SCEV::NoWrapFlags llvm::ScalarEvolution::maskFlags ( SCEV::NoWrapFlags  Flags,
int  Mask 
)
inlinestatic

Convenient NoWrapFlags manipulation that hides enum casts and is visible in the ScalarEvolution name space.

Definition at line 463 of file ScalarEvolution.h.

References llvm::BitmaskEnumDetail::Mask().

Referenced by getAddExpr(), getAddRecExpr(), getMinusSCEV(), getMulExpr(), and StrengthenNoWrapFlags().

◆ print()

void ScalarEvolution::print ( raw_ostream OS) const

◆ properlyDominates()

bool ScalarEvolution::properlyDominates ( const SCEV S,
const BasicBlock BB 
)

Return true if elements that makes up the given SCEV properly dominate the specified basic block.

Definition at line 13125 of file ScalarEvolution.cpp.

References BB, getBlockDisposition(), ProperlyDominatesBlock, and S.

Referenced by WidenIV::createWideIV(), DoInitialMatch(), isAvailableAtLoopEntry(), llvm::isSafeToExpandAt(), and SimplifyICmpOperands().

◆ rewriteUsingPredicate()

const SCEV * ScalarEvolution::rewriteUsingPredicate ( const SCEV S,
const Loop L,
SCEVUnionPredicate A 
)

Re-writes the SCEV according to the Predicates in A.

Definition at line 13523 of file ScalarEvolution.cpp.

References rewrite(), and S.

◆ setFlags()

static LLVM_NODISCARD SCEV::NoWrapFlags llvm::ScalarEvolution::setFlags ( SCEV::NoWrapFlags  Flags,
SCEV::NoWrapFlags  OnFlags 
)
inlinestatic

◆ setNoWrapFlags()

void ScalarEvolution::setNoWrapFlags ( SCEVAddRecExpr AddRec,
SCEV::NoWrapFlags  Flags 
)

Update no-wrap flags of an AddRec.

This may drop the cached info about this AddRec (such as range info) in case if new flags may potentially sharpen it.

Definition at line 5853 of file ScalarEvolution.cpp.

References llvm::SCEVNAryExpr::getNoWrapFlags(), and llvm::SCEVAddRecExpr::setNoWrapFlags().

◆ SimplifyICmpOperands()

bool ScalarEvolution::SimplifyICmpOperands ( ICmpInst::Predicate Pred,
const SCEV *&  LHS,
const SCEV *&  RHS,
unsigned  Depth = 0 
)

◆ SplitIntoInitAndPostInc()

std::pair< const SCEV *, const SCEV * > ScalarEvolution::SplitIntoInitAndPostInc ( const Loop L,
const SCEV S 
)

Splits SCEV expression S into two SCEVs.

One of them is obtained from S by substitution of all AddRec sub-expression related to loop L with initial value of that SCEV. The second is obtained from S by substitution of all AddRec sub-expressions related to loop L with post increment of this AddRec in the loop L. In both cases all other AddRec sub-expressions (not related to L) remain the same. If the S contains non-invariant unknown SCEV the function returns CouldNotCompute SCEV in both values of std::pair. For example, for SCEV S={0, +, 1}<L1> + {0, +, 1}<L2> and loop L=L1 the function returns pair: first = {0, +, 1}<L2> second = {1, +, 1}<L1> + {0, +, 1}<L2> We can see that for the first AddRec sub-expression it was replaced with 0 (initial value) for the first element and to {1, +, 1}<L1> (post increment value) for the second one. In both cases AddRec expression related to L2 remains the same.

Definition at line 9825 of file ScalarEvolution.cpp.

Referenced by isKnownViaInduction().

◆ verify()

void ScalarEvolution::verify ( ) const

◆ willNotOverflow()

bool ScalarEvolution::willNotOverflow ( Instruction::BinaryOps  BinOp,
bool  Signed,
const SCEV LHS,
const SCEV RHS 
)

Is operation BinOp between LHS and RHS provably does not have a signed/unsigned overflow (Signed)?

Definition at line 2253 of file ScalarEvolution.cpp.

References llvm::MCID::Add, B, llvm::SCEV::FlagAnyWrap, llvm::IntegerType::get(), getAddExpr(), getMinusSCEV(), getMulExpr(), getSignExtendExpr(), llvm::SCEV::getType(), getZeroExtendExpr(), llvm_unreachable, Operation, ScalarEvolution(), and Signed.

Referenced by getStrengthenedNoWrapFlagsFromBinOp().

Friends And Related Function Documentation

◆ ScalarEvolutionsTest

friend class ScalarEvolutionsTest
friend

Definition at line 444 of file ScalarEvolution.h.

◆ SCEVCallbackVH

friend class SCEVCallbackVH
friend

Definition at line 1250 of file ScalarEvolution.h.

Referenced by getSCEV().

◆ SCEVExpander

friend class SCEVExpander
friend

Definition at line 1251 of file ScalarEvolution.h.

◆ SCEVUnknown

friend class SCEVUnknown
friend

Definition at line 1252 of file ScalarEvolution.h.

Referenced by getUnknown().


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