KnownFPClass.h

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//===- llvm/Support/KnownFPClass.h - Stores known fpclass -------*- 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 contains a class for representing known fpclasses used by
// computeKnownFPClass.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_SUPPORT_KNOWNFPCLASS_H
#define LLVM_SUPPORT_KNOWNFPCLASS_H
 
#include "llvm/ADT/BitmaskEnum.h"
#include "llvm/ADT/FloatingPointMode.h"
#include "llvm/Support/Compiler.h"
#include <optional>
 
namespace llvm {
class APFloat;
class APInt;
struct fltSemantics;
struct KnownBits;
 
enum class FPClassMask : unsigned {
  kfcNone = 0,
 
  kfcNegQNan = 0x0001,
  kfcNegSNan = 0x0002,
  kfcNegInf = 0x0004,
  kfcNegNormal = 0x0008,
  kfcNegSubnormal = 0x0010,
  kfcNegZero = 0x0020,
  kfcPosZero = 0x0040,
  kfcPosSubnormal = 0x0080,
  kfcPosNormal = 0x0100,
  kfcPosInf = 0x0200,
  kfcPosSNan = 0x0400,
  kfcPosQNan = 0x0800,
 
  kfcSNan = kfcPosSNan | kfcNegSNan,
  kfcQNan = kfcPosQNan | kfcNegQNan,
  kfcPosNan = kfcPosSNan | kfcPosQNan,
  kfcNegNan = kfcNegSNan | kfcNegQNan,
  kfcNan = kfcSNan | kfcQNan,
  kfcInf = kfcPosInf | kfcNegInf,
  kfcNormal = kfcPosNormal | kfcNegNormal,
  kfcSubnormal = kfcPosSubnormal | kfcNegSubnormal,
  kfcZero = kfcPosZero | kfcNegZero,
  kfcPosFinite = kfcPosNormal | kfcPosSubnormal | kfcPosZero,
  kfcNegFinite = kfcNegNormal | kfcNegSubnormal | kfcNegZero,
  kfcFinite = kfcPosFinite | kfcNegFinite,
  kfcPositive = kfcPosFinite | kfcPosInf,
  kfcNegative = kfcNegFinite | kfcNegInf,
  kfcPosSignBit = kfcPositive | kfcPosNan,
  kfcNegSignBit = kfcNegative | kfcNegNan,
 
  kfcAllFlags = kfcNan | kfcInf | kfcFinite,
 
  LLVM_MARK_AS_BITMASK_ENUM(/* LargestValue = */ kfcPosQNan)
};
 
class KnownFPClass {
  FPClassMask KnownFPMask = FPClassMask::kfcAllFlags;
 
  static constexpr FPClassMask toFPClassMask(FPClassTest Classes) {
    FPClassMask Mask = FPClassMask::kfcNone;
 
    if (Classes & fcQNan)
      Mask |= FPClassMask::kfcQNan;
    if (Classes & fcSNan)
      Mask |= FPClassMask::kfcSNan;
    if (Classes & fcNegInf)
      Mask |= FPClassMask::kfcNegInf;
    if (Classes & fcNegNormal)
      Mask |= FPClassMask::kfcNegNormal;
    if (Classes & fcNegSubnormal)
      Mask |= FPClassMask::kfcNegSubnormal;
    if (Classes & fcNegZero)
      Mask |= FPClassMask::kfcNegZero;
    if (Classes & fcPosZero)
      Mask |= FPClassMask::kfcPosZero;
    if (Classes & fcPosSubnormal)
      Mask |= FPClassMask::kfcPosSubnormal;
    if (Classes & fcPosNormal)
      Mask |= FPClassMask::kfcPosNormal;
    if (Classes & fcPosInf)
      Mask |= FPClassMask::kfcPosInf;
 
    return Mask;
  }
 
  static constexpr FPClassMask toFPClassMask(FPClassTest Classes,
                                             bool SignBit) {
    FPClassMask Mask = toFPClassMask(Classes);
 
    // This is the only way to generate a NaN with a specific sign from
    // FPClassTest. SignBit must agree with the input classes.
    if (!SignBit) {
      Mask &= ~FPClassMask::kfcNegNan;
      // If the SignBit is false, then we should not have any negative classes.
      if ((Mask & FPClassMask::kfcNegSignBit) == FPClassMask::kfcNone)
        return Mask;
    } else {
      Mask &= ~FPClassMask::kfcPosNan;
      // If the SignBit is true, then we should not have any positive classes.
      if ((Mask & FPClassMask::kfcPosSignBit) == FPClassMask::kfcNone)
        return Mask;
    }
 
    // SignBit is unknown or inconsistent with the input classes. Expand the
    // possible set to its opposite sign pair.
    if (Classes & fcQNan)
      Mask |= FPClassMask::kfcQNan;
    if (Classes & fcSNan)
      Mask |= FPClassMask::kfcSNan;
    if (Classes & fcInf)
      Mask |= FPClassMask::kfcInf;
    if (Classes & fcNormal)
      Mask |= FPClassMask::kfcNormal;
    if (Classes & fcSubnormal)
      Mask |= FPClassMask::kfcSubnormal;
    if (Classes & fcZero)
      Mask |= FPClassMask::kfcZero;
 
    return Mask;
  }
 
  static constexpr FPClassTest toFPClassTest(FPClassMask Mask) {
    FPClassTest Classes = fcNone;
 
    // Sign of qNaN and sNaN are lost in the conversion.
    if ((Mask & FPClassMask::kfcQNan) != FPClassMask::kfcNone)
      Classes |= fcQNan;
    if ((Mask & FPClassMask::kfcSNan) != FPClassMask::kfcNone)
      Classes |= fcSNan;
 
    if ((Mask & FPClassMask::kfcNegInf) != FPClassMask::kfcNone)
      Classes |= fcNegInf;
    if ((Mask & FPClassMask::kfcNegNormal) != FPClassMask::kfcNone)
      Classes |= fcNegNormal;
    if ((Mask & FPClassMask::kfcNegSubnormal) != FPClassMask::kfcNone)
      Classes |= fcNegSubnormal;
    if ((Mask & FPClassMask::kfcNegZero) != FPClassMask::kfcNone)
      Classes |= fcNegZero;
    if ((Mask & FPClassMask::kfcPosZero) != FPClassMask::kfcNone)
      Classes |= fcPosZero;
    if ((Mask & FPClassMask::kfcPosSubnormal) != FPClassMask::kfcNone)
      Classes |= fcPosSubnormal;
    if ((Mask & FPClassMask::kfcPosNormal) != FPClassMask::kfcNone)
      Classes |= fcPosNormal;
    if ((Mask & FPClassMask::kfcPosInf) != FPClassMask::kfcNone)
      Classes |= fcPosInf;
 
    return Classes;
  }
 
public:
  /// Floating-point classes the value could be one of.
  FPClassTest getKnownFPClasses() const { return toFPClassTest(KnownFPMask); }
 
  void setKnownFPClasses(FPClassTest Classes) {
    KnownFPMask = toFPClassMask(Classes);
  }
 
  /// std::nullopt if the sign bit is unknown, true if the sign bit is
  /// definitely set or false if the sign bit is definitely unset.
  /// By convention, returns false for kfcNone/poison.
  std::optional<bool> getSignBit() const {
    if (KnownFPMask == FPClassMask::kfcNone)
      return false;
 
    if ((KnownFPMask & FPClassMask::kfcPosSignBit) == KnownFPMask)
      return false;
    if ((KnownFPMask & FPClassMask::kfcNegSignBit) == KnownFPMask)
      return true;
 
    return std::nullopt;
  }
 
  void setSignBit(std::optional<bool> Sign) {
    if (Sign && !*Sign) {
      KnownFPMask &= FPClassMask::kfcPosSignBit;
      return;
    }
    if (Sign && *Sign) {
      KnownFPMask &= FPClassMask::kfcNegSignBit;
      return;
    }
    // Set sign to unknown.
    if ((KnownFPMask & FPClassMask::kfcQNan) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcQNan;
    if ((KnownFPMask & FPClassMask::kfcSNan) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcSNan;
    if ((KnownFPMask & FPClassMask::kfcInf) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcInf;
    if ((KnownFPMask & FPClassMask::kfcNormal) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcNormal;
    if ((KnownFPMask & FPClassMask::kfcSubnormal) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcSubnormal;
    if ((KnownFPMask & FPClassMask::kfcZero) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcZero;
  }
 
  KnownFPClass(FPClassMask Known = FPClassMask::kfcAllFlags)
      : KnownFPMask(Known) {}
  KnownFPClass(FPClassTest Known) : KnownFPMask(toFPClassMask(Known)) {}
  KnownFPClass(FPClassTest Known, bool Sign)
      : KnownFPMask(toFPClassMask(Known, Sign)) {}
  LLVM_ABI KnownFPClass(const APFloat &C);
 
  static KnownFPClass getEmpty() { return KnownFPClass(FPClassMask::kfcNone); }
 
  bool operator==(KnownFPClass Other) const {
    return KnownFPMask == Other.KnownFPMask;
  }
 
  /// Return true if it's known this can never be one of the mask entries.
  bool isKnownNever(FPClassMask Mask) const {
    return (KnownFPMask & Mask) == FPClassMask::kfcNone;
  }
 
  /// Return true if it's known this can never be one of the mask entries.
  bool isKnownNever(FPClassTest Mask) const {
    return isKnownNever(toFPClassMask(Mask));
  }
 
  bool isKnownAlways(FPClassMask Mask) const { return isKnownNever(~Mask); }
 
  bool isKnownAlways(FPClassTest Mask) const {
    return isKnownAlways(toFPClassMask(Mask));
  }
 
  bool isUnknown() const { return KnownFPMask == FPClassMask::kfcAllFlags; }
 
  /// Return true if it's known this can never be a nan.
  bool isKnownNeverNaN() const { return isKnownNever(fcNan); }
 
  /// Return true if it's known this must always be a nan.
  bool isKnownAlwaysNaN() const { return isKnownAlways(fcNan); }
 
  /// Return true if it's known this can never be an infinity.
  bool isKnownNeverInfinity() const { return isKnownNever(fcInf); }
 
  /// Return true if it's known this can never be an infinity or nan
  bool isKnownNeverInfOrNaN() const { return isKnownNever(fcInf | fcNan); }
 
  /// Return true if it's known this can never be +infinity.
  bool isKnownNeverPosInfinity() const { return isKnownNever(fcPosInf); }
 
  /// Return true if it's known this can never be -infinity.
  bool isKnownNeverNegInfinity() const { return isKnownNever(fcNegInf); }
 
  /// Return true if it's known this can never be a subnormal
  bool isKnownNeverSubnormal() const { return isKnownNever(fcSubnormal); }
 
  /// Return true if it's known this can never be a positive subnormal
  bool isKnownNeverPosSubnormal() const { return isKnownNever(fcPosSubnormal); }
 
  /// Return true if it's known this can never be a negative subnormal
  bool isKnownNeverNegSubnormal() const { return isKnownNever(fcNegSubnormal); }
 
  /// Return true if it's known this can never be interpreted as a zero. This
  /// extends isKnownNever(fcZero) to cover the case where the assumed
  /// floating-point mode for the function interprets denormals as zero.
  LLVM_ABI bool isKnownNeverLogicalZero(DenormalMode Mode) const;
 
  /// Return true if it's known this can never be interpreted as a negative
  /// zero.
  LLVM_ABI bool isKnownNeverLogicalNegZero(DenormalMode Mode) const;
 
  /// Return true if it's known this can never be interpreted as a positive
  /// zero.
  LLVM_ABI bool isKnownNeverLogicalPosZero(DenormalMode Mode) const;
 
  static constexpr FPClassTest OrderedLessThanZeroMask =
      fcNegSubnormal | fcNegNormal | fcNegInf;
  static constexpr FPClassTest OrderedGreaterThanZeroMask =
      fcPosSubnormal | fcPosNormal | fcPosInf;
 
  /// Return true if we can prove that the analyzed floating-point value is
  /// either NaN or never less than -0.0.
  ///
  ///      NaN --> true
  ///       +0 --> true
  ///       -0 --> true
  ///   x > +0 --> true
  ///   x < -0 --> false
  bool cannotBeOrderedLessThanZero() const {
    return isKnownNever(OrderedLessThanZeroMask);
  }
 
  /// Return true if we can prove that the analyzed floating-point value is
  /// either NaN or never greater than -0.0.
  ///      NaN --> true
  ///       +0 --> true
  ///       -0 --> true
  ///   x > +0 --> false
  ///   x < -0 --> true
  bool cannotBeOrderedGreaterThanZero() const {
    return isKnownNever(OrderedGreaterThanZeroMask);
  }
 
  /// Return true if it's known this can never be a positive value or a logical
  /// 0.
  ///
  ///      NaN --> true
  ///  x <= +0 --> false
  ///     psub --> true if mode is ieee, false otherwise.
  ///   x > +0 --> true
  bool cannotBeOrderedLessEqZero(DenormalMode Mode) const {
    return isKnownNever(fcNegative) && isKnownNeverLogicalPosZero(Mode);
  }
 
  /// Return true if it's know this can never be a negative value or a logical
  /// 0.
  ///
  ///      NaN --> true
  ///  x >= -0 --> false
  ///     nsub --> true if mode is ieee, false otherwise.
  ///   x < -0 --> true
  bool cannotBeOrderedGreaterEqZero(DenormalMode Mode) const {
    return isKnownNever(fcPositive) && isKnownNeverLogicalNegZero(Mode);
  }
 
  /// Return the known classes of \p Src after passing through an input that
  /// may flush subnormals to zero according to \p Mode.
  LLVM_ABI static KnownFPClass applyInputDenormalMode(const KnownFPClass &Src,
                                                      DenormalMode Mode);
 
  /// Return the known classes of \p Src after producing an output that may
  /// flush subnormals to zero according to \p Mode.
  LLVM_ABI static KnownFPClass applyOutputDenormalMode(const KnownFPClass &Src,
                                                       DenormalMode Mode);
 
  KnownFPClass intersectWith(const KnownFPClass &RHS) const {
    return KnownFPClass(KnownFPMask | RHS.KnownFPMask);
  }
 
  KnownFPClass unionWith(const KnownFPClass &RHS) const {
    return KnownFPClass(KnownFPMask & RHS.KnownFPMask);
  }
 
  KnownFPClass &operator|=(const KnownFPClass &RHS) {
    KnownFPMask |= RHS.KnownFPMask;
    return *this;
  }
 
  void knownNot(FPClassMask RuleOut) { KnownFPMask &= ~RuleOut; }
 
  void knownNot(FPClassTest RuleOut) { knownNot(toFPClassMask(RuleOut)); }
 
  void fneg() {
    FPClassMask Known = FPClassMask::kfcNone;
 
    if ((KnownFPMask & FPClassMask::kfcNegQNan) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosQNan;
    if ((KnownFPMask & FPClassMask::kfcNegSNan) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosSNan;
    if ((KnownFPMask & FPClassMask::kfcNegInf) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosInf;
    if ((KnownFPMask & FPClassMask::kfcNegNormal) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosNormal;
    if ((KnownFPMask & FPClassMask::kfcNegSubnormal) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosSubnormal;
    if ((KnownFPMask & FPClassMask::kfcNegZero) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosZero;
    if ((KnownFPMask & FPClassMask::kfcPosZero) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcNegZero;
    if ((KnownFPMask & FPClassMask::kfcPosSubnormal) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcNegSubnormal;
    if ((KnownFPMask & FPClassMask::kfcPosNormal) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcNegNormal;
    if ((KnownFPMask & FPClassMask::kfcPosInf) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcNegInf;
    if ((KnownFPMask & FPClassMask::kfcPosSNan) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcNegSNan;
    if ((KnownFPMask & FPClassMask::kfcPosQNan) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcNegQNan;
 
    KnownFPMask = Known;
  }
 
  static KnownFPClass fneg(const KnownFPClass &Src) {
    KnownFPClass Known = Src;
    Known.fneg();
    return Known;
  }
 
  void fabs() {
    FPClassMask Known = FPClassMask::kfcNone;
 
    if ((KnownFPMask & FPClassMask::kfcQNan) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosQNan;
    if ((KnownFPMask & FPClassMask::kfcSNan) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosSNan;
    if ((KnownFPMask & FPClassMask::kfcInf) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosInf;
    if ((KnownFPMask & FPClassMask::kfcNormal) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosNormal;
    if ((KnownFPMask & FPClassMask::kfcSubnormal) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosSubnormal;
    if ((KnownFPMask & FPClassMask::kfcZero) != FPClassMask::kfcNone)
      Known |= FPClassMask::kfcPosZero;
 
    KnownFPMask = Known;
  }
 
  static KnownFPClass fabs(const KnownFPClass &Src) {
    KnownFPClass Known = Src;
    Known.fabs();
    return Known;
  }
 
  // Enum of min/max intrinsics to avoid dependency on IR.
  enum class MinMaxKind {
    minimum,
    maximum,
    minimumnum,
    maximumnum,
    minnum,
    maxnum
  };
 
  LLVM_ABI static KnownFPClass minMaxLike(const KnownFPClass &LHS,
                                          const KnownFPClass &RHS,
                                          MinMaxKind Kind, DenormalMode Mode);
 
  /// Apply the canonicalize intrinsic to this value.
  LLVM_ABI static KnownFPClass canonicalize(const KnownFPClass &Src,
                                            DenormalMode Mode);
 
  /// Report known values for a bitcast into a float with provided semantics.
  LLVM_ABI static KnownFPClass bitcast(const fltSemantics &FltSemantics,
                                       const KnownBits &Bits);
 
  /// Report known bits for a float with provided semantics.
  LLVM_ABI KnownBits toKnownBits(const fltSemantics &FltSemantics) const;
 
  /// Report known values for fadd
  LLVM_ABI static KnownFPClass fadd(const KnownFPClass &LHS,
                                    const KnownFPClass &RHS, DenormalMode Mode);
 
  /// Report known values for fadd x, x
  LLVM_ABI static KnownFPClass fadd_self(const KnownFPClass &Src,
                                         DenormalMode Mode);
 
  /// Report known values for fsub
  LLVM_ABI static KnownFPClass fsub(const KnownFPClass &LHS,
                                    const KnownFPClass &RHS, DenormalMode Mode);
 
  /// Report known values for fmul
  LLVM_ABI static KnownFPClass fmul(const KnownFPClass &LHS,
                                    const KnownFPClass &RHS, DenormalMode Mode);
 
  // Special case of fmul x, x.
  static KnownFPClass square(const KnownFPClass &Src, DenormalMode Mode) {
    KnownFPClass Known = fmul(Src, Src, Mode);
 
    // X * X is always non-negative or a NaN.
    Known.knownNot(fcNegative);
    Known.propagateNonNaN(Src);
    return Known;
  }
 
  LLVM_ABI static KnownFPClass fmul(const KnownFPClass &LHS, const APFloat &RHS,
                                    DenormalMode Mode);
 
  /// Report known values for fdiv
  LLVM_ABI static KnownFPClass fdiv(const KnownFPClass &LHS,
                                    const KnownFPClass &RHS, DenormalMode Mode);
 
  /// Report known values for fdiv x, x
  LLVM_ABI static KnownFPClass fdiv_self(const KnownFPClass &Src,
                                         DenormalMode Mode);
 
  /// Report known values for frem. Valid for all rounding modes, since frem is
  /// always exact.
  LLVM_ABI static KnownFPClass frem(const KnownFPClass &LHS,
                                    const KnownFPClass &RHS, DenormalMode Mode);
 
  /// Report known values for frem x, x. Valid for all rounding modes.
  LLVM_ABI static KnownFPClass frem_self(const KnownFPClass &Src,
                                         DenormalMode Mode);
 
  /// Report known values for fma
  LLVM_ABI static KnownFPClass fma(const KnownFPClass &LHS,
                                   const KnownFPClass &RHS,
                                   const KnownFPClass &Addend,
                                   DenormalMode Mode);
 
  /// Report known values for fmuladd
  LLVM_ABI static KnownFPClass fmuladd(const KnownFPClass &LHS,
                                       const KnownFPClass &RHS,
                                       const KnownFPClass &Addend,
                                       DenormalMode Mode);
 
  /// Report known values for fma squared, squared, addend
  LLVM_ABI static KnownFPClass fma_square(const KnownFPClass &Squared,
                                          const KnownFPClass &Addend,
                                          DenormalMode Mode);
 
  /// Report known values for fmuladd squared, squared, addend
  LLVM_ABI static KnownFPClass fmuladd_square(const KnownFPClass &Squared,
                                              const KnownFPClass &Addend,
                                              DenormalMode Mode);
 
  /// Propagate known class for sqrt
  LLVM_ABI static KnownFPClass
  sqrt(const KnownFPClass &Src, DenormalMode Mode = DenormalMode::getDynamic());
 
  /// Propagate known class for log/log2/log10
  ///
  /// \p IsMultiUnitFPType if this is for a multi-unit floating-point type.
  LLVM_ABI static KnownFPClass log(const KnownFPClass &Src, DenormalMode Mode,
                                   bool IsMultiUnitFPType);
 
  /// Report known values for exp, exp2 and exp10.
  /// This function assumes that exp10(-1.0) = +0.1 and exp10(+1.0) = +10.0 are
  /// both finite normal values, which holds for formats with a corresponding
  /// LLVM IR type (e.g. does not hold for Float4E2M1FN).
  LLVM_ABI static KnownFPClass exp(const KnownFPClass &Src);
 
  /// Report known values for sin
  LLVM_ABI static KnownFPClass sin(const KnownFPClass &Src);
 
  /// Report known values for cos
  LLVM_ABI static KnownFPClass cos(const KnownFPClass &Src);
 
  /// Report known values for tan
  LLVM_ABI static KnownFPClass tan(const KnownFPClass &Src);
 
  /// Report known values for sinh
  LLVM_ABI static KnownFPClass sinh(const KnownFPClass &Src);
 
  /// Report known values for cosh
  LLVM_ABI static KnownFPClass cosh(const KnownFPClass &Src);
 
  /// Report known values for tanh
  LLVM_ABI static KnownFPClass tanh(const KnownFPClass &Src);
 
  /// Report known values for asin
  LLVM_ABI static KnownFPClass asin(const KnownFPClass &Src);
 
  /// Report known values for acos
  LLVM_ABI static KnownFPClass acos(const KnownFPClass &Src);
 
  /// Report known values for atan
  LLVM_ABI static KnownFPClass atan(const KnownFPClass &Src);
 
  /// Report known values for atan2
  LLVM_ABI static KnownFPClass
  atan2(const KnownFPClass &LHS, const KnownFPClass &RHS, DenormalMode Mode);
 
  /// Return true if the sign bit must be 0, ignoring the sign of nans.
  bool signBitIsZeroOrNaN() const { return isKnownNever(fcNegative); }
 
  /// Assume the sign bit is zero.
  void signBitMustBeZero() { KnownFPMask &= FPClassMask::kfcPosSignBit; }
 
  /// Assume the sign bit is one.
  void signBitMustBeOne() { KnownFPMask &= FPClassMask::kfcNegSignBit; }
 
  void copysign(const KnownFPClass &Sign) {
    // Don't know anything about the sign of the source. Expand the possible set
    // to its opposite sign pair.
 
    if ((KnownFPMask & FPClassMask::kfcQNan) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcQNan;
    if ((KnownFPMask & FPClassMask::kfcSNan) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcSNan;
    if ((KnownFPMask & FPClassMask::kfcInf) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcInf;
    if ((KnownFPMask & FPClassMask::kfcNormal) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcNormal;
    if ((KnownFPMask & FPClassMask::kfcSubnormal) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcSubnormal;
    if ((KnownFPMask & FPClassMask::kfcZero) != FPClassMask::kfcNone)
      KnownFPMask |= FPClassMask::kfcZero;
 
    if (Sign.getSignBit() && !*Sign.getSignBit())
      KnownFPMask &= FPClassMask::kfcPosSignBit;
    if (Sign.getSignBit() && *Sign.getSignBit())
      KnownFPMask &= FPClassMask::kfcNegSignBit;
  }
 
  static KnownFPClass copysign(const KnownFPClass &KnownMag,
                               const KnownFPClass &KnownSign) {
    KnownFPClass Known = KnownMag;
    Known.copysign(KnownSign);
    return Known;
  }
 
  // Propagate knowledge that an operation cannot introduce a signaling NaN.
  void propagateNonSNaN(const KnownFPClass &Src) {
    if (Src.isKnownNever(fcSNan))
      knownNot(fcSNan);
  }
 
  // Propagate knowledge that an operation cannot introduce a signaling NaN.
  void propagateNonSNaN(const KnownFPClass &LHS, const KnownFPClass &RHS) {
    if (LHS.isKnownNever(fcSNan) && RHS.isKnownNever(fcSNan))
      knownNot(fcSNan);
  }
 
  // Propagate knowledge that a non-NaN source implies the result can also not
  // be a NaN. For unconstrained operations, signaling nans are not guaranteed
  // to be quieted but cannot be introduced.
  void propagateNonNaN(const KnownFPClass &Src) {
    propagateNonSNaN(Src);
    if (Src.isKnownNever(fcNan))
      knownNot(fcNan);
  }
 
  void propagateNonNaN(const KnownFPClass &LHS, const KnownFPClass &RHS) {
    propagateNonSNaN(LHS, RHS);
    if (LHS.isKnownNeverNaN() && RHS.isKnownNeverNaN())
      knownNot(fcNan);
  }
 
  /// Propagate known class for fpext. \p DstMode and \p SrcMode are the
  /// denormal modes of the destination and source types.
  LLVM_ABI static KnownFPClass
  fpext(const KnownFPClass &KnownSrc, const fltSemantics &DstTy,
        const fltSemantics &SrcTy, DenormalMode DstMode, DenormalMode SrcMode);
 
  /// Propagate known class for fptrunc and fptrunc_round. \p DstMode and
  /// \p SrcMode are the denormal modes of the destination and source types.
  LLVM_ABI static KnownFPClass fptrunc(const KnownFPClass &KnownSrc,
                                       const fltSemantics &DstTy,
                                       const fltSemantics &SrcTy,
                                       DenormalMode DstMode,
                                       DenormalMode SrcMode);
 
  /// Propagate known class for rounding intrinsics (rint, nearbyint, round,
  /// roundeven). \p IsMultiUnitFPType if this is for a multi-unit
  /// floating-point type.
  LLVM_ABI static KnownFPClass roundToIntegral(const KnownFPClass &Src,
                                               bool IsMultiUnitFPType,
                                               DenormalMode Mode);
 
  /// Propagate known class for trunc.
  LLVM_ABI static KnownFPClass trunc(const KnownFPClass &Src,
                                     DenormalMode Mode);
 
  /// Propagate known class for floor. \p IsMultiUnitFPType if this is for a
  /// multi-unit floating-point type.
  LLVM_ABI static KnownFPClass floor(const KnownFPClass &Src,
                                     bool IsMultiUnitFPType, DenormalMode Mode);
 
  /// Propagate known class for ceil. \p IsMultiUnitFPType if this is for a
  /// multi-unit floating-point type.
  LLVM_ABI static KnownFPClass ceil(const KnownFPClass &Src,
                                    bool IsMultiUnitFPType, DenormalMode Mode);
 
  /// Propagate known class for mantissa component of frexp
  LLVM_ABI static KnownFPClass frexp_mant(const KnownFPClass &Src,
                                          DenormalMode Mode);
 
  /// Propagate known class for ldexp, assuming the exponent is known to be
  /// within [\p ConstantRangeMin, \p ConstantRangeMax]
  ///
  // TODO: This really ought to use ConstantRange, but it's in IR not Support.
  LLVM_ABI static KnownFPClass ldexp(const KnownFPClass &Src,
                                     const APInt &ConstantRangeMin,
                                     const APInt &ConstantRangeMax,
                                     const fltSemantics &Flt,
                                     DenormalMode Mode);
  LLVM_ABI static KnownFPClass ldexp(const KnownFPClass &Src,
                                     const KnownBits &ExpBits,
                                     const fltSemantics &Flt,
                                     DenormalMode Mode);
 
  /// Propagate known class for pow
  LLVM_ABI static KnownFPClass pow(const KnownFPClass &LHS,
                                   const KnownFPClass &RHS);
 
  /// Propagate known class for powi
  LLVM_ABI static KnownFPClass powi(const KnownFPClass &Src,
                                    const KnownBits &N);
 
  void resetAll() { *this = KnownFPClass(); }
};
 
inline KnownFPClass operator|(KnownFPClass LHS, const KnownFPClass &RHS) {
  LHS |= RHS;
  return LHS;
}
 
inline KnownFPClass operator|(const KnownFPClass &LHS, KnownFPClass &&RHS) {
  RHS |= LHS;
  return std::move(RHS);
}
 
} // namespace llvm
 
#endif