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Diffstat (limited to 'contrib/llvm/lib/Support/ConstantRange.cpp')
| -rw-r--r-- | contrib/llvm/lib/Support/ConstantRange.cpp | 652 | 
1 files changed, 652 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Support/ConstantRange.cpp b/contrib/llvm/lib/Support/ConstantRange.cpp new file mode 100644 index 000000000000..8ef3785f5331 --- /dev/null +++ b/contrib/llvm/lib/Support/ConstantRange.cpp @@ -0,0 +1,652 @@ +//===-- ConstantRange.cpp - ConstantRange implementation ------------------===// +// +//                     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 (other integral ranges use min/max values for special range values): +// +//  [F, F) = {}     = Empty set +//  [T, F) = {T} +//  [F, T) = {F} +//  [T, T) = {F, T} = Full set +// +//===----------------------------------------------------------------------===// + +#include "llvm/Constants.h" +#include "llvm/Support/ConstantRange.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Instructions.h" +using namespace llvm; + +/// Initialize a full (the default) or empty set for the specified type. +/// +ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) { +  if (Full) +    Lower = Upper = APInt::getMaxValue(BitWidth); +  else +    Lower = Upper = APInt::getMinValue(BitWidth); +} + +/// Initialize a range to hold the single specified value. +/// +ConstantRange::ConstantRange(const APInt &V) : Lower(V), Upper(V + 1) {} + +ConstantRange::ConstantRange(const APInt &L, const APInt &U) : +  Lower(L), Upper(U) { +  assert(L.getBitWidth() == U.getBitWidth() && +         "ConstantRange with unequal bit widths"); +  assert((L != U || (L.isMaxValue() || L.isMinValue())) && +         "Lower == Upper, but they aren't min or max value!"); +} + +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)); +    } +  } +} + +/// isFullSet - Return true if this set contains all of the elements possible +/// for this data-type +bool ConstantRange::isFullSet() const { +  return Lower == Upper && Lower.isMaxValue(); +} + +/// isEmptySet - Return true if this set contains no members. +/// +bool ConstantRange::isEmptySet() const { +  return Lower == Upper && Lower.isMinValue(); +} + +/// isWrappedSet - Return true if this set wraps around the top of the range, +/// for example: [100, 8) +/// +bool ConstantRange::isWrappedSet() const { +  return Lower.ugt(Upper); +} + +/// getSetSize - Return the number of elements in this set. +/// +APInt ConstantRange::getSetSize() const { +  if (isEmptySet())  +    return APInt(getBitWidth(), 0); +  if (getBitWidth() == 1) { +    if (Lower != Upper)  // One of T or F in the set... +      return APInt(2, 1); +    return APInt(2, 2);      // Must be full set... +  } + +  // Simply subtract the bounds... +  return Upper - Lower; +} + +/// getUnsignedMax - Return the largest unsigned value contained in the +/// ConstantRange. +/// +APInt ConstantRange::getUnsignedMax() const { +  if (isFullSet() || isWrappedSet()) +    return APInt::getMaxValue(getBitWidth()); +  else +    return getUpper() - 1; +} + +/// getUnsignedMin - Return the smallest unsigned value contained in the +/// ConstantRange. +/// +APInt ConstantRange::getUnsignedMin() const { +  if (isFullSet() || (isWrappedSet() && getUpper() != 0)) +    return APInt::getMinValue(getBitWidth()); +  else +    return getLower(); +} + +/// getSignedMax - Return the largest signed value contained in the +/// ConstantRange. +/// +APInt ConstantRange::getSignedMax() const { +  APInt SignedMax(APInt::getSignedMaxValue(getBitWidth())); +  if (!isWrappedSet()) { +    if (getLower().sle(getUpper() - 1)) +      return getUpper() - 1; +    else +      return SignedMax; +  } else { +    if (getLower().isNegative() == getUpper().isNegative()) +      return SignedMax; +    else +      return getUpper() - 1; +  } +} + +/// getSignedMin - Return the smallest signed value contained in the +/// ConstantRange. +/// +APInt ConstantRange::getSignedMin() const { +  APInt SignedMin(APInt::getSignedMinValue(getBitWidth())); +  if (!isWrappedSet()) { +    if (getLower().sle(getUpper() - 1)) +      return getLower(); +    else +      return SignedMin; +  } else { +    if ((getUpper() - 1).slt(getLower())) { +      if (getUpper() != SignedMin) +        return SignedMin; +      else +        return getLower(); +    } else { +      return getLower(); +    } +  } +} + +/// contains - Return true if the specified value is in the set. +/// +bool ConstantRange::contains(const APInt &V) const { +  if (Lower == Upper) +    return isFullSet(); + +  if (!isWrappedSet()) +    return Lower.ule(V) && V.ult(Upper); +  else +    return Lower.ule(V) || V.ult(Upper); +} + +/// 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()); +} + +/// subtract - Subtract the specified constant from the endpoints of this +/// constant range. +ConstantRange ConstantRange::subtract(const APInt &Val) const { +  assert(Val.getBitWidth() == getBitWidth() && "Wrong bit width"); +  // If the set is empty or full, don't modify the endpoints. +  if (Lower == Upper)  +    return *this; +  return ConstantRange(Lower - Val, Upper - Val); +} + +/// 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; +    } else { +      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.ult(Lower)) +        return ConstantRange(CR.Lower, Upper); + +      if (getSetSize().ult(CR.getSetSize())) +        return *this; +      else +        return CR; +    } else 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; +      else +        return CR; +    } + +    if (CR.Lower.ult(Lower)) +      return ConstantRange(Lower, CR.Upper); + +    return CR; +  } else if (CR.Upper.ult(Lower)) { +    if (CR.Lower.ult(Lower)) +      return *this; + +    return ConstantRange(CR.Lower, Upper); +  } +  if (getSetSize().ult(CR.getSetSize())) +    return *this; +  else +    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); + +  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); +      else +        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); +      else +        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 +    if (CR.Lower.ult(Upper) && CR.Upper.ult(Lower)) +      return ConstantRange(Lower, CR.Upper); +  } + +  assert(isWrappedSet() && CR.isWrappedSet() && +         "ConstantRange::unionWith missed wrapped union unwrapped case"); + +  // ------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); +} + +/// zeroExtend - 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 as if the source range had been +/// zero extended. +ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const { +  unsigned SrcTySize = getBitWidth(); +  assert(SrcTySize < DstTySize && "Not a value extension"); +  if (isFullSet()) +    // Change a source full set into [0, 1 << 8*numbytes) +    return ConstantRange(APInt(DstTySize,0), APInt(DstTySize,1).shl(SrcTySize)); + +  APInt L = Lower; L.zext(DstTySize); +  APInt U = Upper; U.zext(DstTySize); +  return ConstantRange(L, U); +} + +/// signExtend - 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 as if the source range had been +/// sign extended. +ConstantRange ConstantRange::signExtend(uint32_t DstTySize) const { +  unsigned SrcTySize = getBitWidth(); +  assert(SrcTySize < DstTySize && "Not a value extension"); +  if (isFullSet()) { +    return ConstantRange(APInt::getHighBitsSet(DstTySize,DstTySize-SrcTySize+1), +                         APInt::getLowBitsSet(DstTySize, SrcTySize-1) + 1); +  } + +  APInt L = Lower; L.sext(DstTySize); +  APInt U = Upper; U.sext(DstTySize); +  return ConstantRange(L, U); +} + +/// truncate - 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 as if the source range had been +/// truncated to the specified type. +ConstantRange ConstantRange::truncate(uint32_t DstTySize) const { +  unsigned SrcTySize = getBitWidth(); +  assert(SrcTySize > DstTySize && "Not a value truncation"); +  APInt Size(APInt::getLowBitsSet(SrcTySize, DstTySize)); +  if (isFullSet() || getSetSize().ugt(Size)) +    return ConstantRange(DstTySize, /*isFullSet=*/true); + +  APInt L = Lower; L.trunc(DstTySize); +  APInt U = Upper; U.trunc(DstTySize); +  return ConstantRange(L, U); +} + +/// zextOrTrunc - make this range have the bit width given by \p DstTySize. The +/// value is zero extended, truncated, or left alone to make it that width. +ConstantRange ConstantRange::zextOrTrunc(uint32_t DstTySize) const { +  unsigned SrcTySize = getBitWidth(); +  if (SrcTySize > DstTySize) +    return truncate(DstTySize); +  else if (SrcTySize < DstTySize) +    return zeroExtend(DstTySize); +  else +    return *this; +} + +/// sextOrTrunc - make this range have the bit width given by \p DstTySize. The +/// value is sign extended, truncated, or left alone to make it that width. +ConstantRange ConstantRange::sextOrTrunc(uint32_t DstTySize) const { +  unsigned SrcTySize = getBitWidth(); +  if (SrcTySize > DstTySize) +    return truncate(DstTySize); +  else if (SrcTySize < DstTySize) +    return signExtend(DstTySize); +  else +    return *this; +} + +ConstantRange +ConstantRange::add(const ConstantRange &Other) const { +  if (isEmptySet() || Other.isEmptySet()) +    return ConstantRange(getBitWidth(), /*isFullSet=*/false); +  if (isFullSet() || Other.isFullSet()) +    return ConstantRange(getBitWidth(), /*isFullSet=*/true); + +  APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize(); +  APInt NewLower = getLower() + Other.getLower(); +  APInt NewUpper = getUpper() + Other.getUpper() - 1; +  if (NewLower == NewUpper) +    return ConstantRange(getBitWidth(), /*isFullSet=*/true); + +  ConstantRange X = ConstantRange(NewLower, NewUpper); +  if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y)) +    // We've wrapped, therefore, full set. +    return ConstantRange(getBitWidth(), /*isFullSet=*/true); + +  return X; +} + +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 Spread_X = getSetSize(), Spread_Y = Other.getSetSize(); +  APInt NewLower = getLower() - Other.getLower(); +  APInt NewUpper = getUpper() - Other.getUpper() + 1; +  if (NewLower == NewUpper) +    return ConstantRange(getBitWidth(), /*isFullSet=*/true); + +  ConstantRange X = ConstantRange(NewLower, NewUpper); +  if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y)) +    // We've wrapped, therefore, full set. +    return ConstantRange(getBitWidth(), /*isFullSet=*/true); + +  return X; +} + +ConstantRange +ConstantRange::multiply(const ConstantRange &Other) const { +  // TODO: If either operand is a single element and the multiply is known to +  // be non-wrapping, round the result min and max value to the appropriate +  // multiple of that element. If wrapping is possible, at least adjust the +  // range according to the greatest power-of-two factor of the single element. + +  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()); +} + +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::umax(const ConstantRange &Other) const { +  // X umax Y is: range(umax(X_umin, Y_umin), +  //                    umax(X_umax, Y_umax)) +  if (isEmptySet() || Other.isEmptySet()) +    return ConstantRange(getBitWidth(), /*isFullSet=*/false); +  APInt NewL = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin()); +  APInt NewU = APIntOps::umax(getUnsignedMax(), Other.getUnsignedMax()) + 1; +  if (NewU == NewL) +    return ConstantRange(getBitWidth(), /*isFullSet=*/true); +  return ConstantRange(NewL, NewU); +} + +ConstantRange +ConstantRange::udiv(const ConstantRange &RHS) const { +  if (isEmptySet() || RHS.isEmptySet() || RHS.getUnsignedMax() == 0) +    return ConstantRange(getBitWidth(), /*isFullSet=*/false); +  if (RHS.isFullSet()) +    return ConstantRange(getBitWidth(), /*isFullSet=*/true); + +  APInt Lower = getUnsignedMin().udiv(RHS.getUnsignedMax()); + +  APInt RHS_umin = RHS.getUnsignedMin(); +  if (RHS_umin == 0) { +    // We want the lowest value in RHS excluding zero. Usually that would be 1 +    // except for a range in the form of [X, 1) in which case it would be X. +    if (RHS.getUpper() == 1) +      RHS_umin = RHS.getLower(); +    else +      RHS_umin = APInt(getBitWidth(), 1); +  } + +  APInt Upper = getUnsignedMax().udiv(RHS_umin) + 1; + +  // If the LHS is Full and the RHS is a wrapped interval containing 1 then +  // this could occur. +  if (Lower == Upper) +    return ConstantRange(getBitWidth(), /*isFullSet=*/true); + +  return ConstantRange(Lower, Upper); +} + +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::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::inverse() const { +  if (isFullSet()) { +    return ConstantRange(getBitWidth(), /*isFullSet=*/false); +  } else if (isEmptySet()) { +    return ConstantRange(getBitWidth(), /*isFullSet=*/true); +  } +  return ConstantRange(Upper, Lower); +} + +/// print - Print out the bounds to a stream... +/// +void ConstantRange::print(raw_ostream &OS) const { +  if (isFullSet()) +    OS << "full-set"; +  else if (isEmptySet()) +    OS << "empty-set"; +  else +    OS << "[" << Lower << "," << Upper << ")"; +} + +/// dump - Allow printing from a debugger easily... +/// +void ConstantRange::dump() const { +  print(dbgs()); +}  | 
