| //===- 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/IR/Instruction.h" |
| #include "llvm/Support/Compiler.h" |
| #include <cstdint> |
| |
| namespace llvm { |
| |
| class MDNode; |
| class raw_ostream; |
| |
| /// This class represents a range of values. |
| class LLVM_NODISCARD ConstantRange { |
| APInt Lower, Upper; |
| |
| 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(APInt Value); |
| |
| /// 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(APInt Lower, APInt 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); |
| |
| /// Produce the exact range such that all values in the returned range satisfy |
| /// the given predicate with any value contained within Other. Formally, this |
| /// returns the exact answer when the superset of 'union over all y in Other |
| /// is exactly same as the subset of intersection over all y in Other. |
| /// { x : icmp op x y is true}'. |
| /// |
| /// Example: Pred = ult and Other = i8 3 returns [0, 3) |
| static ConstantRange makeExactICmpRegion(CmpInst::Predicate Pred, |
| const APInt &Other); |
| |
| /// Return the largest range containing all X such that "X BinOpC Y" is |
| /// guaranteed not to wrap (overflow) for all Y in Other. |
| /// |
| /// NB! The returned set does *not* contain **all** possible values of X for |
| /// which "X BinOpC Y" does not wrap -- some viable values of X may be |
| /// missing, so you cannot use this to constrain X's range. E.g. in the |
| /// fourth example, "(-2) + 1" is both nsw and nuw (so the "X" could be -2), |
| /// but (-2) is not in the set returned. |
| /// |
| /// Examples: |
| /// typedef OverflowingBinaryOperator OBO; |
| /// #define MGNR makeGuaranteedNoWrapRegion |
| /// MGNR(Add, [i8 1, 2), OBO::NoSignedWrap) == [-128, 127) |
| /// MGNR(Add, [i8 1, 2), OBO::NoUnsignedWrap) == [0, -1) |
| /// MGNR(Add, [i8 0, 1), OBO::NoUnsignedWrap) == Full Set |
| /// MGNR(Add, [i8 1, 2), OBO::NoUnsignedWrap | OBO::NoSignedWrap) |
| /// == [0,INT_MAX) |
| /// MGNR(Add, [i8 -1, 6), OBO::NoSignedWrap) == [INT_MIN+1, INT_MAX-4) |
| /// MGNR(Sub, [i8 1, 2), OBO::NoSignedWrap) == [-127, 128) |
| /// MGNR(Sub, [i8 1, 2), OBO::NoUnsignedWrap) == [1, 0) |
| /// MGNR(Sub, [i8 1, 2), OBO::NoUnsignedWrap | OBO::NoSignedWrap) |
| /// == [1,INT_MAX) |
| static ConstantRange makeGuaranteedNoWrapRegion(Instruction::BinaryOps BinOp, |
| const ConstantRange &Other, |
| unsigned NoWrapKind); |
| |
| /// Set up \p Pred and \p RHS such that |
| /// ConstantRange::makeExactICmpRegion(Pred, RHS) == *this. Return true if |
| /// successful. |
| bool getEquivalentICmp(CmpInst::Predicate &Pred, APInt &RHS) const; |
| |
| /// 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; |
| } |
| |
| /// If this set contains all but a single element, return it, otherwise return |
| /// null. |
| const APInt *getSingleMissingElement() const { |
| if (Lower == Upper + 1) |
| return &Upper; |
| 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; |
| |
| /// Compare set size of this range with the range CR. |
| bool isSizeStrictlySmallerThan(const ConstantRange &CR) const; |
| |
| // Compare set size of this range with Value. |
| bool isSizeLargerThan(uint64_t MaxSize) 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; |
| |
| /// 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 representing the possible values resulting |
| /// from an application of the specified cast operator to this range. \p |
| /// BitWidth is the target bitwidth of the cast. For casts which don't |
| /// change bitwidth, it must be the same as the source bitwidth. For casts |
| /// which do change bitwidth, the bitwidth must be consistent with the |
| /// requested cast and source bitwidth. |
| ConstantRange castOp(Instruction::CastOps CastOp, |
| 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 |
| /// 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 application of the specified binary operator to an left hand side |
| /// of this range and a right hand side of \p Other. |
| ConstantRange binaryOp(Instruction::BinaryOps BinOp, |
| const ConstantRange &Other) 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 |
| /// known NSW addition of a value in this range and \p Other constant. |
| ConstantRange addWithNoSignedWrap(const APInt &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 a signed minimum of a value in this range and a value in \p Other. |
| ConstantRange smin(const ConstantRange &Other) const; |
| |
| /// Return a new range representing the possible values resulting |
| /// from an unsigned minimum of a value in this range and a value in \p Other. |
| ConstantRange umin(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 representing the possible values resulting from a |
| /// arithmetic right shift of a value in this range and a value in \p Other. |
| ConstantRange ashr(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; |
| } |
| |
| /// 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 |