diff --git a/lib/Checker/RangeConstraintManager.cpp b/lib/Checker/RangeConstraintManager.cpp
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+//== RangeConstraintManager.cpp - Manage range constraints.------*- C++ -*--==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines RangeConstraintManager, a class that tracks simple
+//  equality and inequality constraints on symbolic values of GRState.
+//
+//===----------------------------------------------------------------------===//
+
+#include "SimpleConstraintManager.h"
+#include "clang/Checker/PathSensitive/GRState.h"
+#include "clang/Checker/PathSensitive/GRStateTrait.h"
+#include "clang/Checker/PathSensitive/GRTransferFuncs.h"
+#include "clang/Checker/ManagerRegistry.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/ImmutableSet.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+
+namespace { class ConstraintRange {}; }
+static int ConstraintRangeIndex = 0;
+
+/// A Range represents the closed range [from, to].  The caller must
+/// guarantee that from <= to.  Note that Range is immutable, so as not
+/// to subvert RangeSet's immutability.
+namespace {
+class Range : public std::pair<const llvm::APSInt*,
+                                                const llvm::APSInt*> {
+public:
+  Range(const llvm::APSInt &from, const llvm::APSInt &to)
+    : std::pair<const llvm::APSInt*, const llvm::APSInt*>(&from, &to) {
+    assert(from <= to);
+  }
+  bool Includes(const llvm::APSInt &v) const {
+    return *first <= v && v <= *second;
+  }
+  const llvm::APSInt &From() const {
+    return *first;
+  }
+  const llvm::APSInt &To() const {
+    return *second;
+  }
+  const llvm::APSInt *getConcreteValue() const {
+    return &From() == &To() ? &From() : NULL;
+  }
+
+  void Profile(llvm::FoldingSetNodeID &ID) const {
+    ID.AddPointer(&From());
+    ID.AddPointer(&To());
+  }
+};
+
+
+class RangeTrait : public llvm::ImutContainerInfo<Range> {
+public:
+  // When comparing if one Range is less than another, we should compare
+  // the actual APSInt values instead of their pointers.  This keeps the order
+  // consistent (instead of comparing by pointer values) and can potentially
+  // be used to speed up some of the operations in RangeSet.
+  static inline bool isLess(key_type_ref lhs, key_type_ref rhs) {
+    return *lhs.first < *rhs.first || (!(*rhs.first < *lhs.first) &&
+                                       *lhs.second < *rhs.second);
+  }
+};
+
+/// RangeSet contains a set of ranges. If the set is empty, then
+///  there the value of a symbol is overly constrained and there are no
+///  possible values for that symbol.
+class RangeSet {
+  typedef llvm::ImmutableSet<Range, RangeTrait> PrimRangeSet;
+  PrimRangeSet ranges; // no need to make const, since it is an
+                       // ImmutableSet - this allows default operator=
+                       // to work.
+public:
+  typedef PrimRangeSet::Factory Factory;
+  typedef PrimRangeSet::iterator iterator;
+
+  RangeSet(PrimRangeSet RS) : ranges(RS) {}
+  RangeSet(Factory& F) : ranges(F.GetEmptySet()) {}
+
+  iterator begin() const { return ranges.begin(); }
+  iterator end() const { return ranges.end(); }
+
+  bool isEmpty() const { return ranges.isEmpty(); }
+
+  /// Construct a new RangeSet representing '{ [from, to] }'.
+  RangeSet(Factory &F, const llvm::APSInt &from, const llvm::APSInt &to)
+    : ranges(F.Add(F.GetEmptySet(), Range(from, to))) {}
+
+  /// Profile - Generates a hash profile of this RangeSet for use
+  ///  by FoldingSet.
+  void Profile(llvm::FoldingSetNodeID &ID) const { ranges.Profile(ID); }
+
+  /// getConcreteValue - If a symbol is contrained to equal a specific integer
+  ///  constant then this method returns that value.  Otherwise, it returns
+  ///  NULL.
+  const llvm::APSInt* getConcreteValue() const {
+    return ranges.isSingleton() ? ranges.begin()->getConcreteValue() : 0;
+  }
+
+  /// AddEQ - Create a new RangeSet with the additional constraint that the
+  ///  value be equal to V.
+  RangeSet AddEQ(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+    // Search for a range that includes 'V'.  If so, return a new RangeSet
+    // representing { [V, V] }.
+    for (PrimRangeSet::iterator i = begin(), e = end(); i!=e; ++i)
+      if (i->Includes(V))
+        return RangeSet(F, V, V);
+
+    return RangeSet(F);
+  }
+
+  /// AddNE - Create a new RangeSet with the additional constraint that the
+  ///  value be not be equal to V.
+  RangeSet AddNE(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+    PrimRangeSet newRanges = ranges;
+
+    // FIXME: We can perhaps enhance ImmutableSet to do this search for us
+    // in log(N) time using the sorted property of the internal AVL tree.
+    for (iterator i = begin(), e = end(); i != e; ++i) {
+      if (i->Includes(V)) {
+        // Remove the old range.
+        newRanges = F.Remove(newRanges, *i);
+        // Split the old range into possibly one or two ranges.
+        if (V != i->From())
+          newRanges = F.Add(newRanges, Range(i->From(), BV.Sub1(V)));
+        if (V != i->To())
+          newRanges = F.Add(newRanges, Range(BV.Add1(V), i->To()));
+        // All of the ranges are non-overlapping, so we can stop.
+        break;
+      }
+    }
+
+    return newRanges;
+  }
+
+  /// AddNE - Create a new RangeSet with the additional constraint that the
+  ///  value be less than V.
+  RangeSet AddLT(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+    PrimRangeSet newRanges = F.GetEmptySet();
+
+    for (iterator i = begin(), e = end() ; i != e ; ++i) {
+      if (i->Includes(V) && i->From() < V)
+        newRanges = F.Add(newRanges, Range(i->From(), BV.Sub1(V)));
+      else if (i->To() < V)
+        newRanges = F.Add(newRanges, *i);
+    }
+
+    return newRanges;
+  }
+
+  RangeSet AddLE(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+    PrimRangeSet newRanges = F.GetEmptySet();
+
+    for (iterator i = begin(), e = end(); i != e; ++i) {
+      // Strictly we should test for includes *V + 1, but no harm is
+      // done by this formulation
+      if (i->Includes(V))
+        newRanges = F.Add(newRanges, Range(i->From(), V));
+      else if (i->To() <= V)
+        newRanges = F.Add(newRanges, *i);
+    }
+
+    return newRanges;
+  }
+
+  RangeSet AddGT(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+    PrimRangeSet newRanges = F.GetEmptySet();
+
+    for (PrimRangeSet::iterator i = begin(), e = end(); i != e; ++i) {
+      if (i->Includes(V) && i->To() > V)
+        newRanges = F.Add(newRanges, Range(BV.Add1(V), i->To()));
+      else if (i->From() > V)
+        newRanges = F.Add(newRanges, *i);
+    }
+
+    return newRanges;
+  }
+
+  RangeSet AddGE(BasicValueFactory &BV, Factory &F, const llvm::APSInt &V) {
+    PrimRangeSet newRanges = F.GetEmptySet();
+
+    for (PrimRangeSet::iterator i = begin(), e = end(); i != e; ++i) {
+      // Strictly we should test for includes *V - 1, but no harm is
+      // done by this formulation
+      if (i->Includes(V))
+        newRanges = F.Add(newRanges, Range(V, i->To()));
+      else if (i->From() >= V)
+        newRanges = F.Add(newRanges, *i);
+    }
+
+    return newRanges;
+  }
+
+  void print(llvm::raw_ostream &os) const {
+    bool isFirst = true;
+    os << "{ ";
+    for (iterator i = begin(), e = end(); i != e; ++i) {
+      if (isFirst)
+        isFirst = false;
+      else
+        os << ", ";
+
+      os << '[' << i->From().toString(10) << ", " << i->To().toString(10)
+         << ']';
+    }
+    os << " }";
+  }
+
+  bool operator==(const RangeSet &other) const {
+    return ranges == other.ranges;
+  }
+};
+} // end anonymous namespace
+
+typedef llvm::ImmutableMap<SymbolRef,RangeSet> ConstraintRangeTy;
+
+namespace clang {
+template<>
+struct GRStateTrait<ConstraintRange>
+  : public GRStatePartialTrait<ConstraintRangeTy> {
+  static inline void* GDMIndex() { return &ConstraintRangeIndex; }
+};
+}
+
+namespace {
+class RangeConstraintManager : public SimpleConstraintManager{
+  RangeSet GetRange(const GRState *state, SymbolRef sym);
+public:
+  RangeConstraintManager(GRSubEngine &subengine)
+    : SimpleConstraintManager(subengine) {}
+
+  const GRState* AssumeSymNE(const GRState* St, SymbolRef sym,
+                             const llvm::APSInt& V);
+
+  const GRState* AssumeSymEQ(const GRState* St, SymbolRef sym,
+                             const llvm::APSInt& V);
+
+  const GRState* AssumeSymLT(const GRState* St, SymbolRef sym,
+                             const llvm::APSInt& V);
+
+  const GRState* AssumeSymGT(const GRState* St, SymbolRef sym,
+                             const llvm::APSInt& V);
+
+  const GRState* AssumeSymGE(const GRState* St, SymbolRef sym,
+                             const llvm::APSInt& V);
+
+  const GRState* AssumeSymLE(const GRState* St, SymbolRef sym,
+                             const llvm::APSInt& V);
+
+  const llvm::APSInt* getSymVal(const GRState* St, SymbolRef sym) const;
+
+  // FIXME: Refactor into SimpleConstraintManager?
+  bool isEqual(const GRState* St, SymbolRef sym, const llvm::APSInt& V) const {
+    const llvm::APSInt *i = getSymVal(St, sym);
+    return i ? *i == V : false;
+  }
+
+  const GRState* RemoveDeadBindings(const GRState* St, SymbolReaper& SymReaper);
+
+  void print(const GRState* St, llvm::raw_ostream& Out,
+             const char* nl, const char *sep);
+
+private:
+  RangeSet::Factory F;
+};
+
+} // end anonymous namespace
+
+ConstraintManager* clang::CreateRangeConstraintManager(GRStateManager&,
+                                                       GRSubEngine &subeng) {
+  return new RangeConstraintManager(subeng);
+}
+
+const llvm::APSInt* RangeConstraintManager::getSymVal(const GRState* St,
+                                                      SymbolRef sym) const {
+  const ConstraintRangeTy::data_type *T = St->get<ConstraintRange>(sym);
+  return T ? T->getConcreteValue() : NULL;
+}
+
+/// Scan all symbols referenced by the constraints. If the symbol is not alive
+/// as marked in LSymbols, mark it as dead in DSymbols.
+const GRState*
+RangeConstraintManager::RemoveDeadBindings(const GRState* state,
+                                           SymbolReaper& SymReaper) {
+
+  ConstraintRangeTy CR = state->get<ConstraintRange>();
+  ConstraintRangeTy::Factory& CRFactory = state->get_context<ConstraintRange>();
+
+  for (ConstraintRangeTy::iterator I = CR.begin(), E = CR.end(); I != E; ++I) {
+    SymbolRef sym = I.getKey();
+    if (SymReaper.maybeDead(sym))
+      CR = CRFactory.Remove(CR, sym);
+  }
+
+  return state->set<ConstraintRange>(CR);
+}
+
+//===------------------------------------------------------------------------===
+// AssumeSymX methods: public interface for RangeConstraintManager.
+//===------------------------------------------------------------------------===/
+
+RangeSet
+RangeConstraintManager::GetRange(const GRState *state, SymbolRef sym) {
+  if (ConstraintRangeTy::data_type* V = state->get<ConstraintRange>(sym))
+    return *V;
+
+  // Lazily generate a new RangeSet representing all possible values for the
+  // given symbol type.
+  QualType T = state->getSymbolManager().getType(sym);
+  BasicValueFactory& BV = state->getBasicVals();
+  return RangeSet(F, BV.getMinValue(T), BV.getMaxValue(T));
+}
+
+//===------------------------------------------------------------------------===
+// AssumeSymX methods: public interface for RangeConstraintManager.
+//===------------------------------------------------------------------------===/
+
+#define AssumeX(OP)\
+const GRState*\
+RangeConstraintManager::AssumeSym ## OP(const GRState* state, SymbolRef sym,\
+  const llvm::APSInt& V){\
+  const RangeSet& R = GetRange(state, sym).Add##OP(state->getBasicVals(), F, V);\
+  return !R.isEmpty() ? state->set<ConstraintRange>(sym, R) : NULL;\
+}
+
+AssumeX(EQ)
+AssumeX(NE)
+AssumeX(LT)
+AssumeX(GT)
+AssumeX(LE)
+AssumeX(GE)
+
+//===------------------------------------------------------------------------===
+// Pretty-printing.
+//===------------------------------------------------------------------------===/
+
+void RangeConstraintManager::print(const GRState* St, llvm::raw_ostream& Out,
+                                   const char* nl, const char *sep) {
+
+  ConstraintRangeTy Ranges = St->get<ConstraintRange>();
+
+  if (Ranges.isEmpty())
+    return;
+
+  Out << nl << sep << "ranges of symbol values:";
+
+  for (ConstraintRangeTy::iterator I=Ranges.begin(), E=Ranges.end(); I!=E; ++I){
+    Out << nl << ' ' << I.getKey() << " : ";
+    I.getData().print(Out);
+  }
+}