class DemandedBits

Declaration

class DemandedBits { /* full declaration omitted */ };

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:40

Member Variables

private llvm::Function& F

private llvm::AssumptionCache& AC

private llvm::DominatorTree& DT

private bool Analyzed = false

private SmallPtrSet<llvm::Instruction*, 32> Visited

private DenseMap<llvm::Instruction*, llvm::APInt> AliveBits

private SmallPtrSet<llvm::Use*, 16> DeadUses

Method Overview

• public DemandedBits(llvm::Function & F, llvm::AssumptionCache & AC, llvm::DominatorTree & DT)
• private void determineLiveOperandBits(const llvm::Instruction * UserI, const llvm::Value * Val, unsigned int OperandNo, const llvm::APInt & AOut, llvm::APInt & AB, llvm::KnownBits & Known, llvm::KnownBits & Known2, bool & KnownBitsComputed)
• public static llvm::APInt determineLiveOperandBitsAdd(unsigned int OperandNo, const llvm::APInt & AOut, const llvm::KnownBits & LHS, const llvm::KnownBits & RHS)
• public static llvm::APInt determineLiveOperandBitsSub(unsigned int OperandNo, const llvm::APInt & AOut, const llvm::KnownBits & LHS, const llvm::KnownBits & RHS)
• public llvm::APInt getDemandedBits(llvm::Instruction * I)
• public llvm::APInt getDemandedBits(llvm::Use * U)
• public bool isInstructionDead(llvm::Instruction * I)
• public bool isUseDead(llvm::Use * U)
• private void performAnalysis()
• public void print(llvm::raw_ostream & OS)

Methods

¶DemandedBits(llvm::Function& F,
             llvm::AssumptionCache& AC,
             llvm::DominatorTree& DT)

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:42

Parameters

llvm::Function& F

llvm::AssumptionCache& AC

llvm::DominatorTree& DT

¶void determineLiveOperandBits(
    const llvm::Instruction* UserI,
    const llvm::Value* Val,
    unsigned int OperandNo,
    const llvm::APInt& AOut,
    llvm::APInt& AB,
    llvm::KnownBits& Known,
    llvm::KnownBits& Known2,
    bool& KnownBitsComputed)

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:83

Parameters

const llvm::Instruction* UserI

const llvm::Value* Val

unsigned int OperandNo

const llvm::APInt& AOut

llvm::APInt& AB

llvm::KnownBits& Known

llvm::KnownBits& Known2

bool& KnownBitsComputed

¶static llvm::APInt determineLiveOperandBitsAdd(
    unsigned int OperandNo,
    const llvm::APInt& AOut,
    const llvm::KnownBits& LHS,
    const llvm::KnownBits& RHS)

Description

Compute alive bits of one addition operand from alive output and known operand bits

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:69

Parameters

unsigned int OperandNo

const llvm::APInt& AOut

const llvm::KnownBits& LHS

const llvm::KnownBits& RHS

¶static llvm::APInt determineLiveOperandBitsSub(
    unsigned int OperandNo,
    const llvm::APInt& AOut,
    const llvm::KnownBits& LHS,
    const llvm::KnownBits& RHS)

Description

Compute alive bits of one subtraction operand from alive output and known operand bits

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:76

Parameters

unsigned int OperandNo

const llvm::APInt& AOut

const llvm::KnownBits& LHS

const llvm::KnownBits& RHS

¶llvm::APInt getDemandedBits(llvm::Instruction* I)

Description

Return the bits demanded from instruction I. For vector instructions individual vector elements are not distinguished: A bit is demanded if it is demanded for any of the vector elements. The size of the return value corresponds to the type size in bits of the scalar type. Instructions that do not have integer or vector of integer type are accepted, but will always produce a mask with all bits set.

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:54

Parameters

llvm::Instruction* I

¶llvm::APInt getDemandedBits(llvm::Use* U)

Description

Return the bits demanded from use U.

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:57

Parameters

llvm::Use* U

¶bool isInstructionDead(llvm::Instruction* I)

Description

Return true if, during analysis, I could not be reached.

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:60

Parameters

llvm::Instruction* I

¶bool isUseDead(llvm::Use* U)

Description

Return whether this use is dead by means of not having any demanded bits.

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:63

Parameters

llvm::Use* U

¶void performAnalysis()

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:82

¶void print(llvm::raw_ostream& OS)

Declared at: llvm/include/llvm/Analysis/DemandedBits.h:65

Parameters

llvm::raw_ostream& OS