llvm/llvm/include/llvm/IR/ConstantRange.h

//===- ConstantRange.h - Represent a range ----------------------*- 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
//
//===----------------------------------------------------------------------===//
//
// Represent a range of possible values that may occur when the program is run
// for an integral value.  This keeps track of a lower and upper bound for the
// constant, which MAY wrap around the end of the numeric range.  To do this, it
// keeps track of a [lower, upper) bound, which specifies an interval just like
// STL iterators.  When used with boolean values, the following are important
// ranges: :
//
//  [F, F) = {}     = Empty set
//  [T, F) = {T}
//  [F, T) = {F}
//  [T, T) = {F, T} = Full set
//
// The other integral ranges use min/max values for special range values. For
// example, for 8-bit types, it uses:
// [0, 0)     = {}       = Empty set
// [255, 255) = {0..255} = Full Set
//
// Note that ConstantRange can be used to represent either signed or
// unsigned ranges.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_IR_CONSTANTRANGE_H
#define LLVM_IR_CONSTANTRANGE_H

#include "llvm/ADT/APInt.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/Support/Compiler.h"
#include <cstdint>

namespace llvm {

class MDNode;
class raw_ostream;
struct KnownBits;

/// This class represents a range of values.
class [[nodiscard]] ConstantRange { … };

inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) { … }

/// Parse out a conservative ConstantRange from !range metadata.
///
/// E.g. if RangeMD is !{i32 0, i32 10, i32 15, i32 20} then return [0, 20).
ConstantRange getConstantRangeFromMetadata(const MDNode &RangeMD);

} // end namespace llvm

#endif // LLVM_IR_CONSTANTRANGE_H