Magic data for optimising unsigned division by a constant. More...

#include "llvm/Support/DivisionByConstantInfo.h"

Collaboration diagram for llvm::UnsignedDivisonByConstantInfo:

[legend]

Static Public Member Functions
static UnsignedDivisonByConstantInfo	get (const APInt &D, unsigned LeadingZeros=0)
	Calculate the magic numbers required to implement an unsigned integer division by a constant as a sequence of multiplies, adds and shifts. More...

Public Attributes
APInt	Magic
	magic number More...

bool	IsAdd
	add indicator More...

unsigned	ShiftAmount
	shift amount More...

Detailed Description

Magic data for optimising unsigned division by a constant.

Definition at line 28 of file DivisionByConstantInfo.h.

Member Function Documentation

◆ get()

UnsignedDivisonByConstantInfo UnsignedDivisonByConstantInfo::get	(	const APInt &	D,
		unsigned	LeadingZeros = `0`
	)

static

Calculate the magic numbers required to implement an unsigned integer division by a constant as a sequence of multiplies, adds and shifts.

Requires that the divisor not be 0. Taken from "Hacker's Delight", Henry S. Warren, Jr., chapter 10. LeadingZeros can be used to simplify the calculation if the upper bits of the divided value are known zero.

Definition at line 66 of file DivisionByConstantInfo.cpp.

References D, llvm::APInt::getAllOnes(), llvm::APInt::getSignedMaxValue(), llvm::APInt::getSignedMinValue(), IsAdd, llvm::APInt::lshr(), Magic, NC, P, R2, ShiftAmount, llvm::APInt::udiv(), llvm::APInt::uge(), and llvm::APInt::ult().