LLVM 22.0.0git
Public Member Functions | Friends | List of all members
llvm::IndexedReference Class Reference

Represents a memory reference as a base pointer and a set of indexing operations. More...

#include "llvm/Analysis/LoopCacheAnalysis.h"

Public Member Functions

 IndexedReference (Instruction &StoreOrLoadInst, const LoopInfo &LI, ScalarEvolution &SE)
 Construct an indexed reference given a StoreOrLoadInst instruction.
bool isValid () const
const SCEV * getBasePointer () const
size_t getNumSubscripts () const
const SCEV * getSubscript (unsigned SubNum) const
const SCEV * getFirstSubscript () const
const SCEV * getLastSubscript () const
std::optional< bool > hasSpacialReuse (const IndexedReference &Other, unsigned CLS, AAResults &AA) const
 Return true/false if the current object and the indexed reference Other are/aren't in the same cache line of size CLS.
std::optional< bool > hasTemporalReuse (const IndexedReference &Other, unsigned MaxDistance, const Loop &L, DependenceInfo &DI, AAResults &AA) const
 Return true if the current object and the indexed reference Other have distance smaller than MaxDistance in the dimension associated with the given loop L.
CacheCostTy computeRefCost (const Loop &L, unsigned CLS) const
 Compute the cost of the reference w.r.t.

Friends

raw_ostream & operator<< (raw_ostream &OS, const IndexedReference &R)

Detailed Description

Represents a memory reference as a base pointer and a set of indexing operations.

For example given the array reference A[i][2j+1][3k+2] in a 3-dim loop nest: for(i=0;i<n;++i) for(j=0;j<m;++j) for(k=0;k<o;++k) ... A[i][2j+1][3k+2] ... We expect: BasePointer -> A Subscripts -> [{0,+,1}<for.i>][{1,+,2}<for.j>][{2,+,3}<for.k>] Sizes -> [m][o][4]

Definition at line 49 of file LoopCacheAnalysis.h.

Constructor & Destructor Documentation

◆ IndexedReference()

IndexedReference::IndexedReference ( Instruction & StoreOrLoadInst,
const LoopInfo & LI,
ScalarEvolution & SE )

Construct an indexed reference given a StoreOrLoadInst instruction.

Definition at line 147 of file LoopCacheAnalysis.cpp.

References assert(), llvm::dbgs(), llvm::isa(), and LLVM_DEBUG.

Referenced by hasSpacialReuse(), hasTemporalReuse(), and operator<<.

Member Function Documentation

◆ computeRefCost()

CacheCostTy IndexedReference::computeRefCost ( const Loop & L,
unsigned CLS ) const

Compute the cost of the reference w.r.t.

the given loop L when it is considered in the innermost position in the loop nest. The cost is defined as:

  • equal to one if the reference is loop invariant, or
  • equal to '(TripCount * stride) / cache_line_size' if:
    • the reference stride is less than the cache line size, and
    • the coefficient of this loop's index variable used in all other subscripts is zero
  • or otherwise equal to 'TripCount'.

Definition at line 272 of file LoopCacheAnalysis.cpp.

References assert(), CacheLineSize, computeTripCount(), llvm::dbgs(), llvm::dyn_cast(), llvm::Type::getExtendedType(), llvm::InstructionCost::getInvalid(), llvm::SCEVAddRecExpr::getLoop(), getNumSubscripts(), getSubscript(), llvm::SCEV::getType(), I, llvm::raw_ostream::indent(), and LLVM_DEBUG.

◆ getBasePointer()

const SCEV * llvm::IndexedReference::getBasePointer ( ) const
inline

Definition at line 58 of file LoopCacheAnalysis.h.

◆ getFirstSubscript()

const SCEV * llvm::IndexedReference::getFirstSubscript ( ) const
inline

Definition at line 64 of file LoopCacheAnalysis.h.

References assert().

◆ getLastSubscript()

const SCEV * llvm::IndexedReference::getLastSubscript ( ) const
inline

Definition at line 68 of file LoopCacheAnalysis.h.

References assert().

Referenced by hasSpacialReuse().

◆ getNumSubscripts()

size_t llvm::IndexedReference::getNumSubscripts ( ) const
inline

Definition at line 59 of file LoopCacheAnalysis.h.

Referenced by computeRefCost(), getSubscript(), and hasSpacialReuse().

◆ getSubscript()

const SCEV * llvm::IndexedReference::getSubscript ( unsigned SubNum) const
inline

Definition at line 60 of file LoopCacheAnalysis.h.

References assert(), and getNumSubscripts().

Referenced by computeRefCost(), and hasSpacialReuse().

◆ hasSpacialReuse()

std::optional< bool > IndexedReference::hasSpacialReuse ( const IndexedReference & Other,
unsigned CLS,
AAResults & AA ) const

Return true/false if the current object and the indexed reference Other are/aren't in the same cache line of size CLS.

Two references are in the same chace line iff the distance between them in the innermost dimension is less than the cache line size. Return std::nullopt if unsure.

Definition at line 160 of file LoopCacheAnalysis.cpp.

References assert(), llvm::dbgs(), llvm::dyn_cast(), getLastSubscript(), getNumSubscripts(), getSubscript(), llvm::SCEVConstant::getValue(), llvm::raw_ostream::indent(), IndexedReference(), LLVM_DEBUG, llvm::Other, and llvm::seq().

◆ hasTemporalReuse()

std::optional< bool > IndexedReference::hasTemporalReuse ( const IndexedReference & Other,
unsigned MaxDistance,
const Loop & L,
DependenceInfo & DI,
AAResults & AA ) const

Return true if the current object and the indexed reference Other have distance smaller than MaxDistance in the dimension associated with the given loop L.

Return false if the distance is not smaller than MaxDistance and std::nullopt if unsure.

Definition at line 215 of file LoopCacheAnalysis.cpp.

References assert(), D(), llvm::dbgs(), llvm::DependenceInfo::depends(), llvm::dyn_cast_or_null(), llvm::ConstantInt::getSExtValue(), llvm::SCEVConstant::getValue(), IndexedReference(), llvm::ConstantInt::isZero(), LLVM_DEBUG, and llvm::Other.

◆ isValid()

bool llvm::IndexedReference::isValid ( ) const
inline

Definition at line 57 of file LoopCacheAnalysis.h.

◆ operator<<

raw_ostream & operator<< ( raw_ostream & OS,
const IndexedReference & R )
friend

References IndexedReference().

The documentation for this class was generated from the following files:
Generated on for LLVM by doxygen 1.14.0