C++ ConstantRange::getBitWidth方法代码示例

// intersect1Wrapped - This helper function is used to intersect two ranges when
// it is known that LHS is wrapped and RHS isn't.
//
ConstantRange 
ConstantRange::intersect1Wrapped(const ConstantRange &LHS,
                                 const ConstantRange &RHS) {
  assert(LHS.isWrappedSet() && !RHS.isWrappedSet());

  // Check to see if we overlap on the Left side of RHS...
  //
  if (RHS.Lower.ult(LHS.Upper)) {
    // We do overlap on the left side of RHS, see if we overlap on the right of
    // RHS...
    if (RHS.Upper.ugt(LHS.Lower)) {
      // Ok, the result overlaps on both the left and right sides.  See if the
      // resultant interval will be smaller if we wrap or not...
      //
      if (LHS.getSetSize().ult(RHS.getSetSize()))
        return LHS;
      else
        return RHS;

    } else {
      // No overlap on the right, just on the left.
      return ConstantRange(RHS.Lower, LHS.Upper);
    }
  } else {
    // We don't overlap on the left side of RHS, see if we overlap on the right
    // of RHS...
    if (RHS.Upper.ugt(LHS.Lower)) {
      // Simple overlap...
      return ConstantRange(LHS.Lower, RHS.Upper);
    } else {
      // No overlap...
      return ConstantRange(LHS.getBitWidth(), false);
    }
  }
}

/// intersectWith - Return the range that results from the intersection of this
/// range with another range.
///
ConstantRange ConstantRange::intersectWith(const ConstantRange &CR) const {
  assert(getBitWidth() == CR.getBitWidth() && 
         "ConstantRange types don't agree!");
  // Handle common special cases
  if (isEmptySet() || CR.isFullSet())  
    return *this;
  if (isFullSet()  || CR.isEmptySet()) 
    return CR;

  if (!isWrappedSet()) {
    if (!CR.isWrappedSet()) {
      using namespace APIntOps;
      APInt L = umax(Lower, CR.Lower);
      APInt U = umin(Upper, CR.Upper);

      if (L.ult(U)) // If range isn't empty...
        return ConstantRange(L, U);
      else
        return ConstantRange(getBitWidth(), false);// Otherwise, empty set
    } else
      return intersect1Wrapped(CR, *this);
  } else {   // We know "this" is wrapped...
    if (!CR.isWrappedSet())
      return intersect1Wrapped(*this, CR);
    else {
      // Both ranges are wrapped...
      using namespace APIntOps;
      APInt L = umax(Lower, CR.Lower);
      APInt U = umin(Upper, CR.Upper);
      return ConstantRange(L, U);
    }
  }
  return *this;
}

ConstantRange
ConstantRange::makeGuaranteedNoWrapRegion(Instruction::BinaryOps BinOp,
                                          const ConstantRange &Other,
                                          unsigned NoWrapKind) {
  typedef OverflowingBinaryOperator OBO;

  // Computes the intersection of CR0 and CR1.  It is different from
  // intersectWith in that the ConstantRange returned will only contain elements
  // in both CR0 and CR1 (i.e. SubsetIntersect(X, Y) is a *subset*, proper or
  // not, of both X and Y).
  auto SubsetIntersect =
      [](const ConstantRange &CR0, const ConstantRange &CR1) {
    return CR0.inverse().unionWith(CR1.inverse()).inverse();
  };

  assert(BinOp >= Instruction::BinaryOpsBegin &&
         BinOp < Instruction::BinaryOpsEnd && "Binary operators only!");

  assert((NoWrapKind == OBO::NoSignedWrap ||
          NoWrapKind == OBO::NoUnsignedWrap ||
          NoWrapKind == (OBO::NoUnsignedWrap | OBO::NoSignedWrap)) &&
         "NoWrapKind invalid!");

  unsigned BitWidth = Other.getBitWidth();
  if (BinOp != Instruction::Add)
    // Conservative answer: empty set
    return ConstantRange(BitWidth, false);

  if (auto *C = Other.getSingleElement())
    if (C->isMinValue())
      // Full set: nothing signed / unsigned wraps when added to 0.
      return ConstantRange(BitWidth);

  ConstantRange Result(BitWidth);

  if (NoWrapKind & OBO::NoUnsignedWrap)
    Result =
        SubsetIntersect(Result, ConstantRange(APInt::getNullValue(BitWidth),
                                              -Other.getUnsignedMax()));

  if (NoWrapKind & OBO::NoSignedWrap) {
    APInt SignedMin = Other.getSignedMin();
    APInt SignedMax = Other.getSignedMax();

    if (SignedMax.isStrictlyPositive())
      Result = SubsetIntersect(
          Result,
          ConstantRange(APInt::getSignedMinValue(BitWidth),
                        APInt::getSignedMinValue(BitWidth) - SignedMax));

    if (SignedMin.isNegative())
      Result = SubsetIntersect(
          Result, ConstantRange(APInt::getSignedMinValue(BitWidth) - SignedMin,
                                APInt::getSignedMinValue(BitWidth)));
  }

  return Result;
}

bool
ConstantRange::isSizeStrictlySmallerThan(const ConstantRange &Other) const {
  assert(getBitWidth() == Other.getBitWidth());
  if (isFullSet())
    return false;
  if (Other.isFullSet())
    return true;
  return (Upper - Lower).ult(Other.Upper - Other.Lower);
}

ConstantRange ConstantRange::makeICmpRegion(unsigned Pred,
                                            const ConstantRange &CR) {
  uint32_t W = CR.getBitWidth();
  switch (Pred) {
    default: assert(!"Invalid ICmp predicate to makeICmpRegion()");
    case ICmpInst::ICMP_EQ:
      return CR;
    case ICmpInst::ICMP_NE:
      if (CR.isSingleElement())
        return ConstantRange(CR.getUpper(), CR.getLower());
      return ConstantRange(W);
    case ICmpInst::ICMP_ULT:
      return ConstantRange(APInt::getMinValue(W), CR.getUnsignedMax());
    case ICmpInst::ICMP_SLT:
      return ConstantRange(APInt::getSignedMinValue(W), CR.getSignedMax());
    case ICmpInst::ICMP_ULE: {
      APInt UMax(CR.getUnsignedMax());
      if (UMax.isMaxValue())
        return ConstantRange(W);
      return ConstantRange(APInt::getMinValue(W), UMax + 1);
    }
    case ICmpInst::ICMP_SLE: {
      APInt SMax(CR.getSignedMax());
      if (SMax.isMaxSignedValue() || (SMax+1).isMaxSignedValue())
        return ConstantRange(W);
      return ConstantRange(APInt::getSignedMinValue(W), SMax + 1);
    }
    case ICmpInst::ICMP_UGT:
      return ConstantRange(CR.getUnsignedMin() + 1, APInt::getNullValue(W));
    case ICmpInst::ICMP_SGT:
      return ConstantRange(CR.getSignedMin() + 1,
                           APInt::getSignedMinValue(W));
    case ICmpInst::ICMP_UGE: {
      APInt UMin(CR.getUnsignedMin());
      if (UMin.isMinValue())
        return ConstantRange(W);
      return ConstantRange(UMin, APInt::getNullValue(W));
    }
    case ICmpInst::ICMP_SGE: {
      APInt SMin(CR.getSignedMin());
      if (SMin.isMinSignedValue())
        return ConstantRange(W);
      return ConstantRange(SMin, APInt::getSignedMinValue(W));
    }
  }
}

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;
}

/// 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 Float2IntPass::validateRange(ConstantRange R) {
  if (R.getBitWidth() > MaxIntegerBW + 1)
    return badRange();
  return R;
}