C++ ConstantRange::isEmptySet方法代码示例

ConstantRange
ConstantRange::lshr(const ConstantRange &Other) const {
  if (isEmptySet() || Other.isEmptySet())
    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
  
  APInt max = getUnsignedMax().lshr(Other.getUnsignedMin());
  APInt min = getUnsignedMin().lshr(Other.getUnsignedMax());
  if (min == max + 1)
    return ConstantRange(getBitWidth(), /*isFullSet=*/true);

  return ConstantRange(min, max + 1);
}

ConstantRange
ConstantRange::umin(const ConstantRange &Other) const {
  // X umin Y is: range(umin(X_umin, Y_umin),
  //                    umin(X_umax, Y_umax))
  if (isEmptySet() || Other.isEmptySet())
    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
  APInt NewL = APIntOps::umin(getUnsignedMin(), Other.getUnsignedMin());
  APInt NewU = APIntOps::umin(getUnsignedMax(), Other.getUnsignedMax()) + 1;
  if (NewU == NewL)
    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
  return ConstantRange(std::move(NewL), std::move(NewU));
}

ConstantRange
ConstantRange::smax(const ConstantRange &Other) const {
  // X smax Y is: range(smax(X_smin, Y_smin),
  //                    smax(X_smax, Y_smax))
  if (isEmptySet() || Other.isEmptySet())
    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
  APInt NewL = APIntOps::smax(getSignedMin(), Other.getSignedMin());
  APInt NewU = APIntOps::smax(getSignedMax(), Other.getSignedMax()) + 1;
  if (NewU == NewL)
    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
  return ConstantRange(NewL, NewU);
}

ConstantRange
ConstantRange::shl(const ConstantRange &Other) const {
  if (isEmptySet() || Other.isEmptySet())
    return ConstantRange(getBitWidth(), /*isFullSet=*/false);

  APInt min = getUnsignedMin().shl(Other.getUnsignedMin());
  APInt max = getUnsignedMax().shl(Other.getUnsignedMax());

  // there's no overflow!
  APInt Zeros(getBitWidth(), getUnsignedMax().countLeadingZeros());
  if (Zeros.ugt(Other.getUnsignedMax()))
    return ConstantRange(min, max + 1);

  // FIXME: implement the other tricky cases
  return ConstantRange(getBitWidth(), /*isFullSet=*/true);
}

ConstantRange
ConstantRange::multiply(const ConstantRange &Other) const {
  if (isEmptySet() || Other.isEmptySet())
    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
  if (isFullSet() || Other.isFullSet())
    return ConstantRange(getBitWidth(), /*isFullSet=*/true);

  APInt this_min = getUnsignedMin().zext(getBitWidth() * 2);
  APInt this_max = getUnsignedMax().zext(getBitWidth() * 2);
  APInt Other_min = Other.getUnsignedMin().zext(getBitWidth() * 2);
  APInt Other_max = Other.getUnsignedMax().zext(getBitWidth() * 2);

  ConstantRange Result_zext = ConstantRange(this_min * Other_min,
                                            this_max * Other_max + 1);
  return Result_zext.truncate(getBitWidth());
}

/// contains - Return true if the argument is a subset of this range.
/// Two equal sets contain each other. The empty set contained by all other
/// sets.
///
bool ConstantRange::contains(const ConstantRange &Other) const {
  if (isFullSet() || Other.isEmptySet()) return true;
  if (isEmptySet() || Other.isFullSet()) return false;

  if (!isWrappedSet()) {
    if (Other.isWrappedSet())
      return false;

    return Lower.ule(Other.getLower()) && Other.getUpper().ule(Upper);
  }

  if (!Other.isWrappedSet())
    return Other.getUpper().ule(Upper) ||
           Lower.ule(Other.getLower());

  return Other.getUpper().ule(Upper) && Lower.ule(Other.getLower());
}

ConstantRange
ConstantRange::sub(const ConstantRange &Other) const {
  if (isEmptySet() || Other.isEmptySet())
    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
  if (isFullSet() || Other.isFullSet())
    return ConstantRange(getBitWidth(), /*isFullSet=*/true);

  APInt NewLower = getLower() - Other.getUpper() + 1;
  APInt NewUpper = getUpper() - Other.getLower();
  if (NewLower == NewUpper)
    return ConstantRange(getBitWidth(), /*isFullSet=*/true);

  ConstantRange X = ConstantRange(std::move(NewLower), std::move(NewUpper));
  if (X.isSizeStrictlySmallerThan(*this) ||
      X.isSizeStrictlySmallerThan(Other))
    // We've wrapped, therefore, full set.
    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
  return X;
}

MyConstantRange binaryAnd(const ConstantRange &Other) const {
  if (isEmptySet() || Other.isEmptySet())
    return MyConstantRange(getBitWidth(), /*isFullSet=*/false);

  if (!isWrappedSet() && !Other.isWrappedSet() && !isFullSet() && !Other.isFullSet()) {
    unsigned width1 = ((getUpper() - 1) ^ getLower()).logBase2() + 1;
    unsigned width2 = ((Other.getUpper() - 1) ^ Other.getLower()).logBase2() + 1;
    APInt res1 = getLower().lshr(width1) << width1;
    APInt res2 = Other.getLower().lshr(width2) << width2;
    APInt res_high1 = getLower();
    APInt res_high2 = Other.getLower();
    res_high1.setLowBits(width1);
    res_high2.setLowBits(width2);
    if ((res1 & res2).isNullValue() && (res_high1 & res_high2).isAllOnesValue()) {
        return MyConstantRange(getBitWidth(), /*isFullSet=*/true);
    }
    return MyConstantRange(res1 & res2, (res_high1 & res_high2) + 1);
  }

  APInt umin = APIntOps::umin(Other.getUnsignedMax(), getUnsignedMax());
  if (umin.isAllOnesValue())
    return MyConstantRange(getBitWidth(), /*isFullSet=*/true);
  return MyConstantRange(APInt::getNullValue(getBitWidth()), std::move(umin) + 1);
}

/// 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 ConstantRange::unionWith(const ConstantRange &CR) const {
  assert(getBitWidth() == CR.getBitWidth() && 
         "ConstantRange types don't agree!");

  if (   isFullSet() || CR.isEmptySet()) return *this;
  if (CR.isFullSet() ||    isEmptySet()) return CR;

  if (!isWrappedSet() && CR.isWrappedSet()) return CR.unionWith(*this);

  APInt L = Lower, U = Upper;

  if (!isWrappedSet() && !CR.isWrappedSet()) {
    if (CR.Lower.ult(L))
      L = CR.Lower;

    if (CR.Upper.ugt(U))
      U = CR.Upper;
  }

  if (isWrappedSet() && !CR.isWrappedSet()) {
    if ((CR.Lower.ult(Upper) && CR.Upper.ult(Upper)) ||
        (CR.Lower.ugt(Lower) && CR.Upper.ugt(Lower))) {
      return *this;
    }

    if (CR.Lower.ule(Upper) && Lower.ule(CR.Upper)) {
      return ConstantRange(getBitWidth());
    }

    if (CR.Lower.ule(Upper) && CR.Upper.ule(Lower)) {
      APInt d1 = CR.Upper - Upper, d2 = Lower - CR.Upper;
      if (d1.ult(d2)) {
        U = CR.Upper;
      } else {
        L = CR.Upper;
      }
    }

    if (Upper.ult(CR.Lower) && CR.Upper.ult(Lower)) {
      APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
      if (d1.ult(d2)) {
        U = CR.Lower + 1;
      } else {
        L = CR.Upper - 1;
      }
    }

    if (Upper.ult(CR.Lower) && Lower.ult(CR.Upper)) {
      APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Lower;

      if (d1.ult(d2)) {
        U = CR.Lower + 1;
      } else {
        L = CR.Lower;
      }
    }
  }

  if (isWrappedSet() && CR.isWrappedSet()) {
    if (Lower.ult(CR.Upper) || CR.Lower.ult(Upper))
      return ConstantRange(getBitWidth());

    if (CR.Upper.ugt(U)) {
      U = CR.Upper;
    }

    if (CR.Lower.ult(L)) {
      L = CR.Lower;
    }

    if (L == U) return ConstantRange(getBitWidth());
  }

  return ConstantRange(L, U);
}

ConstantRange ConstantRange::makeAllowedICmpRegion(CmpInst::Predicate Pred,
                                                   const ConstantRange &CR) {
  if (CR.isEmptySet())
    return CR;

  uint32_t W = CR.getBitWidth();
  switch (Pred) {
  default:
    llvm_unreachable("Invalid ICmp predicate to makeAllowedICmpRegion()");
    case CmpInst::ICMP_EQ:
      return CR;
    case CmpInst::ICMP_NE:
      if (CR.isSingleElement())
        return ConstantRange(CR.getUpper(), CR.getLower());
      return ConstantRange(W);
    case CmpInst::ICMP_ULT: {
      APInt UMax(CR.getUnsignedMax());
      if (UMax.isMinValue())
        return ConstantRange(W, /* empty */ false);
      return ConstantRange(APInt::getMinValue(W), UMax);
    }
    case CmpInst::ICMP_SLT: {
      APInt SMax(CR.getSignedMax());
      if (SMax.isMinSignedValue())
        return ConstantRange(W, /* empty */ false);
      return ConstantRange(APInt::getSignedMinValue(W), SMax);
    }
    case CmpInst::ICMP_ULE: {
      APInt UMax(CR.getUnsignedMax());
      if (UMax.isMaxValue())
        return ConstantRange(W);
      return ConstantRange(APInt::getMinValue(W), UMax + 1);
    }
    case CmpInst::ICMP_SLE: {
      APInt SMax(CR.getSignedMax());
      if (SMax.isMaxSignedValue())
        return ConstantRange(W);
      return ConstantRange(APInt::getSignedMinValue(W), SMax + 1);
    }
    case CmpInst::ICMP_UGT: {
      APInt UMin(CR.getUnsignedMin());
      if (UMin.isMaxValue())
        return ConstantRange(W, /* empty */ false);
      return ConstantRange(UMin + 1, APInt::getNullValue(W));
    }
    case CmpInst::ICMP_SGT: {
      APInt SMin(CR.getSignedMin());
      if (SMin.isMaxSignedValue())
        return ConstantRange(W, /* empty */ false);
      return ConstantRange(SMin + 1, APInt::getSignedMinValue(W));
    }
    case CmpInst::ICMP_UGE: {
      APInt UMin(CR.getUnsignedMin());
      if (UMin.isMinValue())
        return ConstantRange(W);
      return ConstantRange(UMin, APInt::getNullValue(W));
    }
    case CmpInst::ICMP_SGE: {
      APInt SMin(CR.getSignedMin());
      if (SMin.isMinSignedValue())
        return ConstantRange(W);
      return ConstantRange(SMin, APInt::getSignedMinValue(W));
    }
  }
}

/// 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 ConstantRange::unionWith(const ConstantRange &CR) const {
  assert(getBitWidth() == CR.getBitWidth() && 
         "ConstantRange types don't agree!");

  if (   isFullSet() || CR.isEmptySet()) return *this;
  if (CR.isFullSet() ||    isEmptySet()) return CR;

  if (!isWrappedSet() && CR.isWrappedSet()) return CR.unionWith(*this);

  if (!isWrappedSet() && !CR.isWrappedSet()) {
    if (CR.Upper.ult(Lower) || Upper.ult(CR.Lower)) {
      // If the two ranges are disjoint, find the smaller gap and bridge it.
      APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
      if (d1.ult(d2))
        return ConstantRange(Lower, CR.Upper);
      return ConstantRange(CR.Lower, Upper);
    }

    APInt L = Lower, U = Upper;
    if (CR.Lower.ult(L))
      L = CR.Lower;
    if ((CR.Upper - 1).ugt(U - 1))
      U = CR.Upper;

    if (L == 0 && U == 0)
      return ConstantRange(getBitWidth());

    return ConstantRange(L, U);
  }

  if (!CR.isWrappedSet()) {
    // ------U   L-----  and  ------U   L----- : this
    //   L--U                            L--U  : CR
    if (CR.Upper.ule(Upper) || CR.Lower.uge(Lower))
      return *this;

    // ------U   L----- : this
    //    L---------U   : CR
    if (CR.Lower.ule(Upper) && Lower.ule(CR.Upper))
      return ConstantRange(getBitWidth());

    // ----U       L---- : this
    //       L---U       : CR
    //    <d1>  <d2>
    if (Upper.ule(CR.Lower) && CR.Upper.ule(Lower)) {
      APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
      if (d1.ult(d2))
        return ConstantRange(Lower, CR.Upper);
      return ConstantRange(CR.Lower, Upper);
    }

    // ----U     L----- : this
    //        L----U    : CR
    if (Upper.ult(CR.Lower) && Lower.ult(CR.Upper))
      return ConstantRange(CR.Lower, Upper);

    // ------U    L---- : this
    //    L-----U       : CR
    assert(CR.Lower.ult(Upper) && CR.Upper.ult(Lower) &&
           "ConstantRange::unionWith missed a case with one range wrapped");
    return ConstantRange(Lower, CR.Upper);
  }

  // ------U    L----  and  ------U    L---- : this
  // -U  L-----------  and  ------------U  L : CR
  if (CR.Lower.ule(Upper) || Lower.ule(CR.Upper))
    return ConstantRange(getBitWidth());

  APInt L = Lower, U = Upper;
  if (CR.Upper.ugt(U))
    U = CR.Upper;
  if (CR.Lower.ult(L))
    L = CR.Lower;

  return ConstantRange(L, U);
}

/// intersectWith - 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 ConstantRange::intersectWith(const ConstantRange &CR) const {
  assert(getBitWidth() == CR.getBitWidth() && 
         "ConstantRange types don't agree!");

  // Handle common cases.
  if (   isEmptySet() || CR.isFullSet()) return *this;
  if (CR.isEmptySet() ||    isFullSet()) return CR;

  if (!isWrappedSet() && CR.isWrappedSet())
    return CR.intersectWith(*this);

  if (!isWrappedSet() && !CR.isWrappedSet()) {
    if (Lower.ult(CR.Lower)) {
      if (Upper.ule(CR.Lower))
        return ConstantRange(getBitWidth(), false);

      if (Upper.ult(CR.Upper))
        return ConstantRange(CR.Lower, Upper);

      return CR;
    }
    if (Upper.ult(CR.Upper))
      return *this;

    if (Lower.ult(CR.Upper))
      return ConstantRange(Lower, CR.Upper);

    return ConstantRange(getBitWidth(), false);
  }

  if (isWrappedSet() && !CR.isWrappedSet()) {
    if (CR.Lower.ult(Upper)) {
      if (CR.Upper.ult(Upper))
        return CR;

      if (CR.Upper.ule(Lower))
        return ConstantRange(CR.Lower, Upper);

      if (getSetSize().ult(CR.getSetSize()))
        return *this;
      return CR;
    }
    if (CR.Lower.ult(Lower)) {
      if (CR.Upper.ule(Lower))
        return ConstantRange(getBitWidth(), false);

      return ConstantRange(Lower, CR.Upper);
    }
    return CR;
  }

  if (CR.Upper.ult(Upper)) {
    if (CR.Lower.ult(Upper)) {
      if (getSetSize().ult(CR.getSetSize()))
        return *this;
      return CR;
    }

    if (CR.Lower.ult(Lower))
      return ConstantRange(Lower, CR.Upper);

    return CR;
  }
  if (CR.Upper.ule(Lower)) {
    if (CR.Lower.ult(Lower))
      return *this;

    return ConstantRange(CR.Lower, Upper);
  }
  if (getSetSize().ult(CR.getSetSize()))
    return *this;
  return CR;
}