X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FConstantRange.cpp;h=b6f823465266caf50089eac58e70041e3c017f1c;hb=559c277aa9242dd5b32d2f2ccc353d938f886ee9;hp=bb458d4c6b07b57e56df4cc45bf0ba7cce595e03;hpb=a3755d8d366fdd7a2415b93ac0253f8e677c9dfd;p=oota-llvm.git

diff --git a/lib/Support/ConstantRange.cpp b/lib/Support/ConstantRange.cpp
index bb458d4c6b0..b6f82346526 100644
--- a/lib/Support/ConstantRange.cpp
+++ b/lib/Support/ConstantRange.cpp
@@ -21,44 +21,15 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/InstrTypes.h"
 #include "llvm/Support/ConstantRange.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
-/// Initialize a range to hold the single specified value.
-///
-ConstantRangeBase::ConstantRangeBase(const APInt & V)
-  : Lower(V), Upper(V + 1) {}
-
-ConstantRangeBase::ConstantRangeBase(const APInt &L, const APInt &U)
-  : Lower(L), Upper(U) {
-  assert(L.getBitWidth() == U.getBitWidth() &&
-         "ConstantRange with unequal bit widths");
-}
-
-/// print - Print out the bounds to a stream...
-///
-void ConstantRangeBase::print(raw_ostream &OS) const {
-  OS << "[" << Lower << "," << Upper << ")";
-}
-
-/// dump - Allow printing from a debugger easily...
-///
-void ConstantRangeBase::dump() const {
-  print(errs());
-}
-
-std::ostream &llvm::operator<<(std::ostream &o,
-                               const ConstantRangeBase &CR) {
-  raw_os_ostream OS(o);
-  OS << CR;
-  return o;
-}
-
 /// Initialize a full (the default) or empty set for the specified type.
 ///
-ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) :
-  ConstantRangeBase(APInt(BitWidth, 0), APInt(BitWidth, 0)) {
+ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) {
   if (Full)
     Lower = Upper = APInt::getMaxValue(BitWidth);
   else
@@ -67,14 +38,81 @@ ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) :
 
 /// Initialize a range to hold the single specified value.
 ///
-ConstantRange::ConstantRange(const APInt & V) : ConstantRangeBase(V) {}
+ConstantRange::ConstantRange(const APInt &V) : Lower(V), Upper(V + 1) {}
 
-ConstantRange::ConstantRange(const APInt &L, const APInt &U)
-  : ConstantRangeBase(L, U) {
+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) {
+  if (CR.isEmptySet())
+    return CR;
+
+  uint32_t W = CR.getBitWidth();
+  switch (Pred) {
+    default: assert(!"Invalid ICmp predicate to makeICmpRegion()");
+    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));
+    }
+  }
+}
+
 /// isFullSet - Return true if this set contains all of the elements possible
 /// for this data-type
 bool ConstantRange::isFullSet() const {
@@ -94,6 +132,14 @@ bool ConstantRange::isWrappedSet() const {
   return Lower.ugt(Upper);
 }
 
+/// isSignWrappedSet - Return true if this set wraps around the INT_MIN of
+/// its bitwidth, for example: i8 [120, 140).
+///
+bool ConstantRange::isSignWrappedSet() const {
+  return contains(APInt::getSignedMaxValue(getBitWidth())) &&
+         contains(APInt::getSignedMinValue(getBitWidth()));
+}
+
 /// getSetSize - Return the number of elements in this set.
 ///
 APInt ConstantRange::getSetSize() const {
@@ -140,14 +186,10 @@ APInt ConstantRange::getSignedMax() const {
     else
       return SignedMax;
   } else {
-    if ((getUpper() - 1).slt(getLower())) {
-      if (getLower() != SignedMax)
-        return SignedMax;
-      else
-        return getUpper() - 1;
-    } else {
+    if (getLower().isNegative() == getUpper().isNegative())
+      return SignedMax;
+    else
       return getUpper() - 1;
-    }
   }
 }
 
@@ -185,6 +227,28 @@ bool ConstantRange::contains(const APInt &V) const {
     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 {
@@ -195,90 +259,12 @@ ConstantRange ConstantRange::subtract(const APInt &Val) const {
   return ConstantRange(Lower - Val, Upper - Val);
 }
 
-
-// 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.
-///
+/// 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 special cases
-  if (isEmptySet() || CR.isFullSet())  
-    return *this;
-  if (isFullSet()  || CR.isEmptySet()) 
-    return CR;
-
-  if (!isWrappedSet()) {
-    if (!CR.isWrappedSet()) {
-      APInt L = APIntOps::umax(Lower, CR.Lower);
-      APInt U = APIntOps::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...
-      APInt L = APIntOps::umax(Lower, CR.Lower);
-      APInt U = APIntOps::umin(Upper, CR.Upper);
-      return ConstantRange(L, U);
-    }
-  }
-  return *this;
-}
-
-/// maximalIntersectWith - 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.maximalIntersectWith(B) might not
-/// be equal to B.maximalIntersect(A).
-ConstantRange
-ConstantRange::maximalIntersectWith(const ConstantRange &CR) const {
   assert(getBitWidth() == CR.getBitWidth() && 
          "ConstantRange types don't agree!");
 
@@ -287,7 +273,7 @@ ConstantRange::maximalIntersectWith(const ConstantRange &CR) const {
   if (CR.isEmptySet() ||    isFullSet()) return CR;
 
   if (!isWrappedSet() && CR.isWrappedSet())
-    return CR.maximalIntersectWith(*this);
+    return CR.intersectWith(*this);
 
   if (!isWrappedSet() && !CR.isWrappedSet()) {
     if (Lower.ult(CR.Lower)) {
@@ -370,69 +356,74 @@ ConstantRange ConstantRange::unionWith(const ConstantRange &CR) const {
 
   if (!isWrappedSet() && CR.isWrappedSet()) return CR.unionWith(*this);
 
-  APInt L = Lower, U = Upper;
-
   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.ugt(U))
+    if ((CR.Upper - 1).ugt(U - 1))
       U = CR.Upper;
+
+    if (L == 0 && U == 0)
+      return ConstantRange(getBitWidth());
+
+    return ConstantRange(L, U);
   }
 
-  if (isWrappedSet() && !CR.isWrappedSet()) {
-    if ((CR.Lower.ult(Upper) && CR.Upper.ult(Upper)) ||
-        (CR.Lower.ugt(Lower) && CR.Upper.ugt(Lower))) {
+  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;
-    }
 
-    if (CR.Lower.ule(Upper) && Lower.ule(CR.Upper)) {
+    // ------U   L----- : this
+    //    L---------U   : CR
+    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)) {
+    // ----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)) {
-        U = CR.Lower + 1;
-      } else {
-        L = CR.Upper - 1;
-      }
+      if (d1.ult(d2))
+        return ConstantRange(Lower, CR.Upper);
+      else
+        return ConstantRange(CR.Lower, Upper);
     }
 
-    if (Upper.ult(CR.Lower) && Lower.ult(CR.Upper)) {
-      APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Lower;
+    // ----U     L----- : this
+    //        L----U    : CR
+    if (Upper.ult(CR.Lower) && Lower.ult(CR.Upper))
+      return ConstantRange(CR.Lower, Upper);
 
-      if (d1.ult(d2)) {
-        U = CR.Lower + 1;
-      } else {
-        L = CR.Lower;
-      }
-    }
+    // ------U    L---- : this
+    //    L-----U       : CR
+    if (CR.Lower.ult(Upper) && CR.Upper.ult(Lower))
+      return ConstantRange(Lower, CR.Upper);
   }
 
-  if (isWrappedSet() && CR.isWrappedSet()) {
-    if (Lower.ult(CR.Upper) || CR.Lower.ult(Upper))
-      return ConstantRange(getBitWidth());
-
-    if (CR.Upper.ugt(U)) {
-      U = CR.Upper;
-    }
+  assert(isWrappedSet() && CR.isWrappedSet() &&
+         "ConstantRange::unionWith missed wrapped union unwrapped case");
 
-    if (CR.Lower.ult(L)) {
-      L = CR.Lower;
-    }
+  // ------U    L----  and  ------U    L---- : this
+  // -U  L-----------  and  ------------U  L : CR
+  if (CR.Lower.ule(Upper) || Lower.ule(CR.Upper))
+    return ConstantRange(getBitWidth());
 
-    if (L == U) 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);
 }
@@ -442,15 +433,15 @@ ConstantRange ConstantRange::unionWith(const ConstantRange &CR) const {
 /// correspond to the possible range of values as if the source range had been
 /// zero extended.
 ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const {
+  if (isEmptySet()) return ConstantRange(DstTySize, /*isFullSet=*/false);
+
   unsigned SrcTySize = getBitWidth();
   assert(SrcTySize < DstTySize && "Not a value extension");
-  if (isFullSet())
-    // Change a source full set into [0, 1 << 8*numbytes)
+  if (isFullSet() || isWrappedSet())
+    // Change into [0, 1 << src bit width)
     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);
+  return ConstantRange(Lower.zext(DstTySize), Upper.zext(DstTySize));
 }
 
 /// signExtend - Return a new range in the specified integer type, which must
@@ -458,16 +449,16 @@ ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const {
 /// correspond to the possible range of values as if the source range had been
 /// sign extended.
 ConstantRange ConstantRange::signExtend(uint32_t DstTySize) const {
+  if (isEmptySet()) return ConstantRange(DstTySize, /*isFullSet=*/false);
+
   unsigned SrcTySize = getBitWidth();
   assert(SrcTySize < DstTySize && "Not a value extension");
-  if (isFullSet()) {
+  if (isFullSet() || isSignWrappedSet()) {
     return ConstantRange(APInt::getHighBitsSet(DstTySize,DstTySize-SrcTySize+1),
-                         APInt::getLowBitsSet(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);
+  return ConstantRange(Lower.sext(DstTySize), Upper.sext(DstTySize));
 }
 
 /// truncate - Return a new range in the specified integer type, which must be
@@ -479,17 +470,41 @@ ConstantRange ConstantRange::truncate(uint32_t DstTySize) const {
   assert(SrcTySize > DstTySize && "Not a value truncation");
   APInt Size(APInt::getLowBitsSet(SrcTySize, DstTySize));
   if (isFullSet() || getSetSize().ugt(Size))
-    return ConstantRange(DstTySize);
+    return ConstantRange(DstTySize, /*isFullSet=*/true);
 
-  APInt L = Lower; L.trunc(DstTySize);
-  APInt U = Upper; U.trunc(DstTySize);
-  return ConstantRange(L, U);
+  return ConstantRange(Lower.trunc(DstTySize), Upper.trunc(DstTySize));
+}
+
+/// 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();
@@ -505,18 +520,60 @@ ConstantRange::add(const ConstantRange &Other) const {
   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.getUpper() + 1;
+  APInt NewUpper = getUpper() - Other.getLower();
+  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: Implement multiply.
-  return ConstantRange(getBitWidth(),
-                       !(isEmptySet() || Other.isEmptySet()));
+  // 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 {
-  // TODO: Implement smax.
-  return ConstantRange(getBitWidth(),
-                       !(isEmptySet() || Other.isEmptySet()));
+  // 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
@@ -525,8 +582,6 @@ ConstantRange::umax(const ConstantRange &Other) const {
   //                    umax(X_umax, Y_umax))
   if (isEmptySet() || Other.isEmptySet())
     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
-  if (isFullSet() || Other.isFullSet())
-    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
   APInt NewL = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
   APInt NewU = APIntOps::umax(getUnsignedMax(), Other.getUnsignedMax()) + 1;
   if (NewU == NewL)
@@ -535,491 +590,112 @@ ConstantRange::umax(const ConstantRange &Other) const {
 }
 
 ConstantRange
-ConstantRange::udiv(const ConstantRange &Other) const {
-  // TODO: Implement udiv.
-  return ConstantRange(getBitWidth(),
-                       !(isEmptySet() || Other.isEmptySet()));
-}
-
-/// Initialize a full (the default) or empty set for the specified type.
-///
-ConstantSignedRange::ConstantSignedRange(uint32_t BitWidth, bool Full) :
-  ConstantRangeBase(APInt(BitWidth, 0), APInt(BitWidth, 0)) {
-  if (Full)
-    Lower = Upper = APInt::getSignedMaxValue(BitWidth);
-  else
-    Lower = Upper = APInt::getSignedMinValue(BitWidth);
-}
-
-/// Initialize a range to hold the single specified value.
-///
-ConstantSignedRange::ConstantSignedRange(const APInt & V)
-  : ConstantRangeBase(V) {}
-
-ConstantSignedRange::ConstantSignedRange(const APInt &L, const APInt &U)
-  : ConstantRangeBase(L, U) {
-  assert((L != U || (L.isMaxSignedValue() || L.isMinSignedValue())) &&
-         "Lower == Upper, but they aren't min or max value!");
-}
-
-/// isFullSet - Return true if this set contains all of the elements possible
-/// for this data-type
-bool ConstantSignedRange::isFullSet() const {
-  return Lower == Upper && Lower.isMaxSignedValue();
-}
-
-/// isEmptySet - Return true if this set contains no members.
-///
-bool ConstantSignedRange::isEmptySet() const {
-  return Lower == Upper && Lower.isMinSignedValue();
-}
-
-/// isWrappedSet - Return true if this set wraps around the top of the range,
-/// for example: [100, 8)
-///
-bool ConstantSignedRange::isWrappedSet() const {
-  return Lower.sgt(Upper);
-}
-
-/// getSetSize - Return the number of elements in this set.
-///
-APInt ConstantSignedRange::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;
-}
-
-/// getSignedMax - Return the largest signed value contained in the
-/// ConstantSignedRange.
-///
-APInt ConstantSignedRange::getSignedMax() const {
-  if (isFullSet() || isWrappedSet())
-    return APInt::getSignedMaxValue(getBitWidth());
-  else
-    return getUpper() - 1;
-}
+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);
 
-/// getSignedMin - Return the smallest signed value contained in the
-/// ConstantSignedRange.
-///
-APInt ConstantSignedRange::getSignedMin() const {
-  if (isFullSet() || (isWrappedSet() &&
-                      getUpper() != APInt::getSignedMinValue(getBitWidth())))
-    return APInt::getSignedMinValue(getBitWidth());
-  else
-    return getLower();
-}
+  APInt Lower = getUnsignedMin().udiv(RHS.getUnsignedMax());
 
-/// getUnsignedMax - Return the largest unsigned value contained in the
-/// ConstantSignedRange.
-///
-APInt ConstantSignedRange::getUnsignedMax() const {
-  APInt UnsignedMax(APInt::getMaxValue(getBitWidth()));
-  if (!isWrappedSet()) {
-    if (getLower().ule(getUpper() - 1))
-      return getUpper() - 1;
+  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
-      return UnsignedMax;
-  } else {
-    if ((getUpper() - 1).ult(getLower())) {
-      if (getLower() != UnsignedMax)
-        return UnsignedMax;
-      else
-        return getUpper() - 1;
-    } else {
-      return getUpper() - 1;
-    }
+      RHS_umin = APInt(getBitWidth(), 1);
   }
-}
 
-/// getUnsignedMin - Return the smallest unsigned value contained in the
-/// ConstantSignedRange.
-///
-APInt ConstantSignedRange::getUnsignedMin() const {
-  APInt UnsignedMin(APInt::getMinValue(getBitWidth()));
-  if (!isWrappedSet()) {
-    if (getLower().ule(getUpper() - 1))
-      return getLower();
-    else
-      return UnsignedMin;
-  } else {
-    if ((getUpper() - 1).ult(getLower())) {
-      if (getUpper() != UnsignedMin)
-        return UnsignedMin;
-      else
-        return getLower();
-    } else {
-      return getLower();
-    }
-  }
-}
+  APInt Upper = getUnsignedMax().udiv(RHS_umin) + 1;
 
-/// contains - Return true if the specified value is in the set.
-///
-bool ConstantSignedRange::contains(const APInt &V) const {
+  // If the LHS is Full and the RHS is a wrapped interval containing 1 then
+  // this could occur.
   if (Lower == Upper)
-    return isFullSet();
-
-  if (!isWrappedSet())
-    return Lower.sle(V) && V.slt(Upper);
-  else
-    return Lower.sle(V) || V.slt(Upper);
-}
+    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 
-/// subtract - Subtract the specified constant from the endpoints of this
-/// constant range.
-ConstantSignedRange ConstantSignedRange::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 ConstantSignedRange(Lower - Val, Upper - Val);
+  return ConstantRange(Lower, Upper);
 }
 
+ConstantRange
+ConstantRange::binaryAnd(const ConstantRange &Other) const {
+  if (isEmptySet() || Other.isEmptySet())
+    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 
-// intersect1Wrapped - This helper function is used to intersect two ranges when
-// it is known that LHS is wrapped and RHS isn't.
-//
-ConstantSignedRange
-ConstantSignedRange::intersect1Wrapped(const ConstantSignedRange &LHS,
-                                 const ConstantSignedRange &RHS) {
-  assert(LHS.isWrappedSet() && !RHS.isWrappedSet());
-
-  // Check to see if we overlap on the Left side of RHS...
-  //
-  if (RHS.Lower.slt(LHS.Upper)) {
-    // We do overlap on the left side of RHS, see if we overlap on the right of
-    // RHS...
-    if (RHS.Upper.sgt(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;
+  // TODO: replace this with something less conservative
 
-    } else {
-      // No overlap on the right, just on the left.
-      return ConstantSignedRange(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.sgt(LHS.Lower)) {
-      // Simple overlap...
-      return ConstantSignedRange(LHS.Lower, RHS.Upper);
-    } else {
-      // No overlap...
-      return ConstantSignedRange(LHS.getBitWidth(), false);
-    }
-  }
+  APInt umin = APIntOps::umin(Other.getUnsignedMax(), getUnsignedMax());
+  if (umin.isAllOnesValue())
+    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
+  return ConstantRange(APInt::getNullValue(getBitWidth()), umin + 1);
 }
 
-/// intersectWith - Return the range that results from the intersection of this
-/// range with another range.
-///
-ConstantSignedRange
-ConstantSignedRange::intersectWith(const ConstantSignedRange &CR) const {
-  assert(getBitWidth() == CR.getBitWidth() &&
-         "ConstantSignedRange types don't agree!");
-  // Handle common special cases
-  if (isEmptySet() || CR.isFullSet())
-    return *this;
-  if (isFullSet()  || CR.isEmptySet())
-    return CR;
+ConstantRange
+ConstantRange::binaryOr(const ConstantRange &Other) const {
+  if (isEmptySet() || Other.isEmptySet())
+    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 
-  if (!isWrappedSet()) {
-    if (!CR.isWrappedSet()) {
-      APInt L = APIntOps::smax(Lower, CR.Lower);
-      APInt U = APIntOps::smin(Upper, CR.Upper);
+  // TODO: replace this with something less conservative
 
-      if (L.slt(U)) // If range isn't empty...
-        return ConstantSignedRange(L, U);
-      else
-        return ConstantSignedRange(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...
-      APInt L = APIntOps::smax(Lower, CR.Lower);
-      APInt U = APIntOps::smin(Upper, CR.Upper);
-      return ConstantSignedRange(L, U);
-    }
-  }
-  return *this;
+  APInt umax = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
+  if (umax.isMinValue())
+    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
+  return ConstantRange(umax, APInt::getNullValue(getBitWidth()));
 }
 
-/// maximalIntersectWith - 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.maximalIntersectWith(B) might not
-/// be equal to B.maximalIntersect(A).
-ConstantSignedRange
-ConstantSignedRange::maximalIntersectWith(const ConstantSignedRange &CR) const {
-  assert(getBitWidth() == CR.getBitWidth() &&
-         "ConstantSignedRange 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.maximalIntersectWith(*this);
-
-  if (!isWrappedSet() && !CR.isWrappedSet()) {
-    if (Lower.slt(CR.Lower)) {
-      if (Upper.sle(CR.Lower))
-        return ConstantSignedRange(getBitWidth(), false);
-
-      if (Upper.slt(CR.Upper))
-        return ConstantSignedRange(CR.Lower, Upper);
-
-      return CR;
-    } else {
-      if (Upper.slt(CR.Upper))
-        return *this;
-
-      if (Lower.slt(CR.Upper))
-        return ConstantSignedRange(Lower, CR.Upper);
-
-      return ConstantSignedRange(getBitWidth(), false);
-    }
-  }
-
-  if (isWrappedSet() && !CR.isWrappedSet()) {
-    if (CR.Lower.slt(Upper)) {
-      if (CR.Upper.slt(Upper))
-        return CR;
-
-      if (CR.Upper.slt(Lower))
-        return ConstantSignedRange(CR.Lower, Upper);
-
-      if (getSetSize().ult(CR.getSetSize()))
-        return *this;
-      else
-        return CR;
-    } else if (CR.Lower.slt(Lower)) {
-      if (CR.Upper.sle(Lower))
-        return ConstantSignedRange(getBitWidth(), false);
-
-      return ConstantSignedRange(Lower, CR.Upper);
-    }
-    return CR;
-  }
-
-  if (CR.Upper.slt(Upper)) {
-    if (CR.Lower.slt(Upper)) {
-      if (getSetSize().ult(CR.getSetSize()))
-        return *this;
-      else
-        return CR;
-    }
+ConstantRange
+ConstantRange::shl(const ConstantRange &Other) const {
+  if (isEmptySet() || Other.isEmptySet())
+    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
 
-    if (CR.Lower.slt(Lower))
-      return ConstantSignedRange(Lower, CR.Upper);
+  APInt min = getUnsignedMin().shl(Other.getUnsignedMin());
+  APInt max = getUnsignedMax().shl(Other.getUnsignedMax());
 
-    return CR;
-  } else if (CR.Upper.slt(Lower)) {
-    if (CR.Lower.slt(Lower))
-      return *this;
+  // there's no overflow!
+  APInt Zeros(getBitWidth(), getUnsignedMax().countLeadingZeros());
+  if (Zeros.ugt(Other.getUnsignedMax()))
+    return ConstantRange(min, max + 1);
 
-    return ConstantSignedRange(CR.Lower, Upper);
-  }
-  if (getSetSize().ult(CR.getSetSize()))
-    return *this;
-  else
-    return CR;
+  // 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);
 
-/// 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.
-///
-ConstantSignedRange
-ConstantSignedRange::unionWith(const ConstantSignedRange &CR) const {
-  assert(getBitWidth() == CR.getBitWidth() &&
-         "ConstantSignedRange 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.slt(L))
-      L = CR.Lower;
-
-    if (CR.Upper.sgt(U))
-      U = CR.Upper;
-  }
-
-  if (isWrappedSet() && !CR.isWrappedSet()) {
-    if ((CR.Lower.slt(Upper) && CR.Upper.slt(Upper)) ||
-        (CR.Lower.sgt(Lower) && CR.Upper.sgt(Lower))) {
-      return *this;
-    }
-
-    if (CR.Lower.sle(Upper) && Lower.sle(CR.Upper)) {
-      return ConstantSignedRange(getBitWidth());
-    }
-
-    if (CR.Lower.sle(Upper) && CR.Upper.sle(Lower)) {
-      APInt d1 = CR.Upper - Upper, d2 = Lower - CR.Upper;
-      if (d1.slt(d2)) {
-        U = CR.Upper;
-      } else {
-        L = CR.Upper;
-      }
-    }
-
-    if (Upper.slt(CR.Lower) && CR.Upper.slt(Lower)) {
-      APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
-      if (d1.slt(d2)) {
-        U = CR.Lower + 1;
-      } else {
-        L = CR.Upper - 1;
-      }
-    }
-
-    if (Upper.slt(CR.Lower) && Lower.slt(CR.Upper)) {
-      APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Lower;
-
-      if (d1.slt(d2)) {
-        U = CR.Lower + 1;
-      } else {
-        L = CR.Lower;
-      }
-    }
-  }
-
-  if (isWrappedSet() && CR.isWrappedSet()) {
-    if (Lower.slt(CR.Upper) || CR.Lower.slt(Upper))
-      return ConstantSignedRange(getBitWidth());
-
-    if (CR.Upper.sgt(U)) {
-      U = CR.Upper;
-    }
-
-    if (CR.Lower.slt(L)) {
-      L = CR.Lower;
-    }
-
-    if (L == U) return ConstantSignedRange(getBitWidth());
-  }
-
-  return ConstantSignedRange(L, U);
+  return ConstantRange(min, max + 1);
 }
 
-/// 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.
-ConstantSignedRange ConstantSignedRange::zeroExtend(uint32_t DstTySize) const {
-  unsigned SrcTySize = getBitWidth();
-  assert(SrcTySize < DstTySize && "Not a value extension");
-  if (isEmptySet())
-    return ConstantSignedRange(SrcTySize, /*isFullSet=*/false);
-  if (isFullSet())
-    // Change a source full set into [0, 1 << 8*numbytes)
-    return ConstantSignedRange(APInt(DstTySize,0),
-                               APInt(DstTySize,1).shl(SrcTySize));
-
-  APInt L, U;
-  if (Lower.isNegative() && !Upper.isNegative()) {
-    L = APInt(SrcTySize, 0);
-    U = APInt::getSignedMinValue(SrcTySize);
-  } else {
-    L = Lower;
-    U = Upper;
+ConstantRange ConstantRange::inverse() const {
+  if (isFullSet()) {
+    return ConstantRange(getBitWidth(), /*isFullSet=*/false);
+  } else if (isEmptySet()) {
+    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
   }
-  L.zext(DstTySize);
-  U.zext(DstTySize);
-  return ConstantSignedRange(L, U);
+  return ConstantRange(Upper, Lower);
 }
 
-/// 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.
-ConstantSignedRange ConstantSignedRange::signExtend(uint32_t DstTySize) const {
-  unsigned SrcTySize = getBitWidth();
-  assert(SrcTySize < DstTySize && "Not a value extension");
-  if (isEmptySet())
-    return ConstantSignedRange(SrcTySize, /*isFullSet=*/false);
+/// print - Print out the bounds to a stream...
+///
+void ConstantRange::print(raw_ostream &OS) const {
   if (isFullSet())
-    return ConstantSignedRange(APInt(getSignedMin()).sext(DstTySize),
-                               APInt(getSignedMax()).sext(DstTySize)+1);
-
-  APInt L = Lower; L.sext(DstTySize);
-  APInt U = Upper; U.sext(DstTySize);
-  return ConstantSignedRange(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.
-ConstantSignedRange ConstantSignedRange::truncate(uint32_t DstTySize) const {
-  // TODO: Implement truncate.
-  return ConstantSignedRange(DstTySize, !isEmptySet());
-}
-
-ConstantSignedRange
-ConstantSignedRange::add(const ConstantSignedRange &Other) const {
-  // TODO: Implement add.
-  return ConstantSignedRange(getBitWidth(),
-                             !(isEmptySet() || Other.isEmptySet()));
-}
-
-ConstantSignedRange
-ConstantSignedRange::multiply(const ConstantSignedRange &Other) const {
-  // TODO: Implement multiply.
-  return ConstantSignedRange(getBitWidth(),
-                             !(isEmptySet() || Other.isEmptySet()));
-}
-
-ConstantSignedRange
-ConstantSignedRange::smax(const ConstantSignedRange &Other) const {
-  // X smax Y is: range(smax(X_smin, Y_smin),
-  //                    smax(X_smax, Y_smax))
-  if (isEmptySet() || Other.isEmptySet())
-    return ConstantSignedRange(getBitWidth(), /*isFullSet=*/false);
-  if (isFullSet() || Other.isFullSet())
-    return ConstantSignedRange(getBitWidth(), /*isFullSet=*/true);
-  APInt NewL = APIntOps::smax(getSignedMin(), Other.getSignedMin());
-  APInt NewU = APIntOps::smax(getSignedMax(), Other.getSignedMax()) + 1;
-  if (NewU == NewL)
-    return ConstantSignedRange(getBitWidth(), /*isFullSet=*/true);
-  return ConstantSignedRange(NewL, NewU);
-}
-
-ConstantSignedRange
-ConstantSignedRange::umax(const ConstantSignedRange &Other) const {
-  // TODO: Implement umax.
-  return ConstantSignedRange(getBitWidth(),
-                             !(isEmptySet() || Other.isEmptySet()));
+    OS << "full-set";
+  else if (isEmptySet())
+    OS << "empty-set";
+  else
+    OS << "[" << Lower << "," << Upper << ")";
 }
 
-ConstantSignedRange
-ConstantSignedRange::udiv(const ConstantSignedRange &Other) const {
-  // TODO: Implement udiv.
-  return ConstantSignedRange(getBitWidth(),
-                             !(isEmptySet() || Other.isEmptySet()));
+/// dump - Allow printing from a debugger easily...
+///
+void ConstantRange::dump() const {
+  print(dbgs());
 }