//===- ConstantRange.h - Represent a range ----------------------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file 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 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/Support/DataTypes.h" namespace llvm { /// This class represents a range of values. /// class ConstantRange { APInt Lower, Upper; // If we have move semantics, pass APInts by value and move them into place. typedef APInt APIntMoveTy; public: /// Initialize a full (the default) or empty set for the specified bit width. /// explicit ConstantRange(uint32_t BitWidth, bool isFullSet = true); /// Initialize a range to hold the single specified value. /// ConstantRange(APIntMoveTy 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(APIntMoveTy Lower, APIntMoveTy Upper); /// Produce the smallest range such that all values that may satisfy the given /// predicate with any value contained within Other is contained in the /// returned range. Formally, this returns a superset of /// 'union over all y in Other . { x : icmp op x y is true }'. If the exact /// answer is not representable as a ConstantRange, the return value will be a /// proper superset of the above. /// /// Example: Pred = ult and Other = i8 [2, 5) returns Result = [0, 4) static ConstantRange makeAllowedICmpRegion(CmpInst::Predicate Pred, const ConstantRange &Other); /// Produce the largest range such that all values in the returned range /// satisfy the given predicate with all values contained within Other. /// Formally, this returns a subset of /// 'intersection over all y in Other . { x : icmp op x y is true }'. If the /// exact answer is not representable as a ConstantRange, the return value /// will be a proper subset of the above. /// /// Example: Pred = ult and Other = i8 [2, 5) returns [0, 2) static ConstantRange makeSatisfyingICmpRegion(CmpInst::Predicate Pred, const ConstantRange &Other); /// Return the largest range containing all X such that "X BinOpC C" does not /// wrap (overflow). /// /// Example: /// typedef OverflowingBinaryOperator OBO; /// makeNoWrapRegion(Add, i8 1, OBO::NoSignedWrap) == [-128, 127) /// makeNoWrapRegion(Add, i8 1, OBO::NoUnsignedWrap) == [0, -1) /// makeNoWrapRegion(Add, i8 0, OBO::NoUnsignedWrap) == Full Set static ConstantRange makeNoWrapRegion(Instruction::BinaryOps BinOp, const APInt &C, unsigned NoWrapKind); /// Return the lower value for this range. /// const APInt &getLower() const { return Lower; } /// Return the upper value for this range. /// const APInt &getUpper() const { return Upper; } /// Get the bit width of this ConstantRange. /// uint32_t getBitWidth() const { return Lower.getBitWidth(); } /// Return true if this set contains all of the elements possible /// for this data-type. /// bool isFullSet() const; /// Return true if this set contains no members. /// bool isEmptySet() const; /// Return true if this set wraps around the top of the range. /// For example: [100, 8). /// bool isWrappedSet() const; /// Return true if this set wraps around the INT_MIN of /// its bitwidth. For example: i8 [120, 140). /// bool isSignWrappedSet() const; /// Return true if the specified value is in the set. /// bool contains(const APInt &Val) const; /// Return true if the other range is a subset of this one. /// bool contains(const ConstantRange &CR) const; /// If this set contains a single element, return it, otherwise return null. /// const APInt *getSingleElement() const { if (Upper == Lower + 1) return &Lower; return nullptr; } /// Return true if this set contains exactly one member. /// bool isSingleElement() const { return getSingleElement() != nullptr; } /// Return the number of elements in this set. /// APInt getSetSize() const; /// Return the largest unsigned value contained in the ConstantRange. /// APInt getUnsignedMax() const; /// Return the smallest unsigned value contained in the ConstantRange. /// APInt getUnsignedMin() const; /// Return the largest signed value contained in the ConstantRange. /// APInt getSignedMax() const; /// Return the smallest signed value contained in the ConstantRange. /// APInt getSignedMin() const; /// 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 the specified constant from the endpoints of this constant range. ConstantRange subtract(const APInt &CI) const; /// \brief Subtract the specified range from this range (aka relative /// complement of the sets). ConstantRange difference(const ConstantRange &CR) const; /// Return the range that results from the intersection of /// this range with another range. The resultant range is guaranteed to /// include all elements contained in both input ranges, and to have the /// smallest possible set size that does so. Because there may be two /// intersections with the same set size, A.intersectWith(B) might not /// be equal to B.intersectWith(A). /// ConstantRange intersectWith(const ConstantRange &CR) const; /// 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; /// 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; /// 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; /// 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; /// Make this range have the bit width given by \p BitWidth. The /// value is zero extended, truncated, or left alone to make it that width. ConstantRange zextOrTrunc(uint32_t BitWidth) const; /// Make this range have the bit width given by \p BitWidth. The /// value is sign extended, truncated, or left alone to make it that width. ConstantRange sextOrTrunc(uint32_t BitWidth) const; /// Return a new range representing the possible values resulting /// from an addition of a value in this range and a value in \p Other. ConstantRange add(const ConstantRange &Other) const; /// Return a new range representing the possible values resulting /// from a subtraction of a value in this range and a value in \p Other. ConstantRange sub(const ConstantRange &Other) const; /// Return a new range representing the possible values resulting /// from a multiplication of a value in this range and a value in \p Other, /// treating both this and \p Other as unsigned ranges. ConstantRange multiply(const ConstantRange &Other) const; /// Return a new range representing the possible values resulting /// from a signed maximum of a value in this range and a value in \p Other. ConstantRange smax(const ConstantRange &Other) const; /// Return a new range representing the possible values resulting /// from an unsigned maximum of a value in this range and a value in \p Other. ConstantRange umax(const ConstantRange &Other) const; /// Return a new range representing the possible values resulting /// from an unsigned division of a value in this range and a value in /// \p Other. ConstantRange udiv(const ConstantRange &Other) const; /// Return a new range representing the possible values resulting /// from a binary-and of a value in this range by a value in \p Other. ConstantRange binaryAnd(const ConstantRange &Other) const; /// Return a new range representing the possible values resulting /// from a binary-or of a value in this range by a value in \p Other. ConstantRange binaryOr(const ConstantRange &Other) const; /// Return a new range representing the possible values resulting /// from a left shift of a value in this range by a value in \p Other. /// TODO: This isn't fully implemented yet. ConstantRange shl(const ConstantRange &Other) const; /// Return a new range representing the possible values resulting from a /// logical right shift of a value in this range and a value in \p Other. ConstantRange lshr(const ConstantRange &Other) const; /// Return a new range that is the logical not of the current set. /// ConstantRange inverse() const; /// Print out the bounds to a stream. /// void print(raw_ostream &OS) const; /// Allow printing from a debugger easily. /// void dump() const; }; inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) { CR.print(OS); return OS; } } // End llvm namespace #endif