llvm/llvm/lib/Support/DivisionByConstantInfo.cpp

//===----- DivisionByConstantInfo.cpp - division by constant -*- C++ -*----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// This file implements support for optimizing divisions by a constant
///
//===----------------------------------------------------------------------===//

#include "llvm/Support/DivisionByConstantInfo.h"

usingnamespacellvm;

/// Calculate the magic numbers required to implement a signed integer division
/// by a constant as a sequence of multiplies, adds and shifts.  Requires that
/// the divisor not be 0, 1, or -1.  Taken from "Hacker's Delight", Henry S.
/// Warren, Jr., Chapter 10.
SignedDivisionByConstantInfo SignedDivisionByConstantInfo::get(const APInt &D) { … }

/// 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.
UnsignedDivisionByConstantInfo
UnsignedDivisionByConstantInfo::get(const APInt &D, unsigned LeadingZeros,
                                    bool AllowEvenDivisorOptimization) { … }