#include "llvm/Analysis/DemandedBits.h"

Public Member Functions
	DemandedBits (Function &F, AssumptionCache &AC, DominatorTree &DT)

APInt	getDemandedBits (Instruction *I)
	Return the bits demanded from instruction I.

APInt	getDemandedBits (Use *U)
	Return the bits demanded from use U.

bool	isInstructionDead (Instruction *I)
	Return true if, during analysis, I could not be reached.

bool	isUseDead (Use *U)
	Return whether this use is dead by means of not having any demanded bits.

void	print (raw_ostream &OS)

Static Public Member Functions
static APInt	determineLiveOperandBitsAdd (unsigned OperandNo, const APInt &AOut, const KnownBits &LHS, const KnownBits &RHS)
	Compute alive bits of one addition operand from alive output and known operand bits.

static APInt	determineLiveOperandBitsSub (unsigned OperandNo, const APInt &AOut, const KnownBits &LHS, const KnownBits &RHS)
	Compute alive bits of one subtraction operand from alive output and known operand bits.

Detailed Description

Definition at line 40 of file DemandedBits.h.

Constructor & Destructor Documentation

◆ DemandedBits()

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

inline

Definition at line 42 of file DemandedBits.h.

References F.

Member Function Documentation

◆ determineLiveOperandBitsAdd()

APInt DemandedBits::determineLiveOperandBitsAdd	(	unsigned	OperandNo,
		const APInt &	AOut,
		const KnownBits &	LHS,
		const KnownBits &	RHS
	)

static

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

Definition at line 552 of file DemandedBits.cpp.

References determineLiveOperandBitsAddCarry(), LHS, and RHS.

◆ determineLiveOperandBitsSub()

APInt DemandedBits::determineLiveOperandBitsSub	(	unsigned	OperandNo,
		const APInt &	AOut,
		const KnownBits &	LHS,
		const KnownBits &	RHS
	)

static

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

Definition at line 560 of file DemandedBits.cpp.

References determineLiveOperandBitsAddCarry(), LHS, llvm::KnownBits::One, RHS, and llvm::KnownBits::Zero.

◆ getDemandedBits() [1/2]

APInt DemandedBits::getDemandedBits ( Instruction * I )

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.

Definition at line 399 of file DemandedBits.cpp.

References DL, llvm::APInt::getAllOnes(), and I.

Referenced by llvm::slpvectorizer::BoUpSLP::computeMinimumValueSizes(), getDemandedBits(), and print().