llvm-6502/include/llvm/Support/ConstantRange.h
2007-04-07 15:41:33 +00:00

190 lines
6.4 KiB
C++

//===-- llvm/Support/ConstantRange.h - Represent a range --------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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 always keeps unsigned values.
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_CONSTANT_RANGE_H
#define LLVM_SUPPORT_CONSTANT_RANGE_H
#include "llvm/ADT/APInt.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/Streams.h"
#include <iosfwd>
namespace llvm {
class ConstantRange {
APInt Lower, Upper;
static ConstantRange intersect1Wrapped(const ConstantRange &LHS,
const ConstantRange &RHS);
public:
/// Initialize a full (the default) or empty set for the specified bit width.
///
ConstantRange(uint32_t BitWidth, bool isFullSet = true);
/// Initialize a range to hold the single specified value.
///
ConstantRange(const APInt &Value);
/// @brief Initialize a range of values explicitly. This will assert out if
/// Lower==Upper and Lower != Min or Max value for its type. It will also
/// assert out if the two APInt's are not the same bit width.
ConstantRange(const APInt& Lower, const APInt& Upper);
/// getLower - Return the lower value for this range...
///
const APInt &getLower() const { return Lower; }
/// getUpper - Return the upper value for this range...
///
const APInt &getUpper() const { return Upper; }
/// getBitWidth - get the bit width of this ConstantRange
///
uint32_t getBitWidth() const { return Lower.getBitWidth(); }
/// isFullSet - Return true if this set contains all of the elements possible
/// for this data-type
///
bool isFullSet() const;
/// isEmptySet - Return true if this set contains no members.
///
bool isEmptySet() const;
/// isWrappedSet - Return true if this set wraps around the top of the range,
/// for example: [100, 8)
///
bool isWrappedSet() const;
/// contains - Return true if the specified value is in the set.
///
bool contains(const APInt &Val) const;
/// getSingleElement - If this set contains a single element, return it,
/// otherwise return null.
///
const APInt *getSingleElement() const {
if (Upper == Lower + 1)
return &Lower;
return 0;
}
/// isSingleElement - Return true if this set contains exactly one member.
///
bool isSingleElement() const { return getSingleElement() != 0; }
/// getSetSize - Return the number of elements in this set.
///
APInt getSetSize() const;
/// getUnsignedMax - Return the largest unsigned value contained in the
/// ConstantRange.
///
APInt getUnsignedMax() const;
/// getUnsignedMin - Return the smallest unsigned value contained in the
/// ConstantRange.
///
APInt getUnsignedMin() const;
/// getSignedMax - Return the largest signed value contained in the
/// ConstantRange.
///
APInt getSignedMax() const;
/// getSignedMin - Return the smallest signed value contained in the
/// ConstantRange.
///
APInt getSignedMin() const;
/// operator== - Return true if this range is equal to another range.
///
bool operator==(const ConstantRange &CR) const {
return Lower == CR.Lower && Upper == CR.Upper;
}
bool operator!=(const ConstantRange &CR) const {
return !operator==(CR);
}
/// subtract - Subtract the specified constant from the endpoints of this
/// constant range.
ConstantRange subtract(const APInt &CI) const;
/// intersectWith - Return the range that results from the intersection of
/// this range with another range. The resultant range is pruned as much as
/// possible, but there may be cases where elements are included that are in
/// one of the sets but not the other. For example: [100, 8) intersect [3,
/// 120) yields [3, 120)
///
ConstantRange intersectWith(const ConstantRange &CR) const;
/// unionWith - Return the range that results from the union of this range
/// with another range. The resultant range is guaranteed to include the
/// elements of both sets, but may contain more. For example, [3, 9) union
/// [12,15) is [3, 15), which includes 9, 10, and 11, which were not included
/// in either set before.
///
ConstantRange unionWith(const ConstantRange &CR) const;
/// zeroExtend - Return a new range in the specified integer type, which must
/// be strictly larger than the current type. The returned range will
/// correspond to the possible range of values if the source range had been
/// zero extended to BitWidth.
ConstantRange zeroExtend(uint32_t BitWidth) const;
/// signExtend - Return a new range in the specified integer type, which must
/// be strictly larger than the current type. The returned range will
/// correspond to the possible range of values if the source range had been
/// sign extended to BitWidth.
ConstantRange signExtend(uint32_t BitWidth) const;
/// truncate - Return a new range in the specified integer type, which must be
/// strictly smaller than the current type. The returned range will
/// correspond to the possible range of values if the source range had been
/// truncated to the specified type.
ConstantRange truncate(uint32_t BitWidth) const;
/// print - Print out the bounds to a stream...
///
void print(std::ostream &OS) const;
void print(std::ostream *OS) const { if (OS) print(*OS); }
/// dump - Allow printing from a debugger easily...
///
void dump() const;
};
inline std::ostream &operator<<(std::ostream &OS, const ConstantRange &CR) {
CR.print(OS);
return OS;
}
} // End llvm namespace
#endif