diff --git a/include/llvm/Instructions.h b/include/llvm/Instructions.h
index 3f67e26..89a5a30 100644
--- a/include/llvm/Instructions.h
+++ b/include/llvm/Instructions.h
@@ -20,8 +20,8 @@
 #include "llvm/DerivedTypes.h"
 #include "llvm/Attributes.h"
 #include "llvm/CallingConv.h"
-#include "llvm/Support/ConstantRangesSet.h"
-#include "llvm/Support/CRSBuilder.h"
+#include "llvm/Support/IntegersSubset.h"
+#include "llvm/Support/IntegersSubsetMapping.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -2589,7 +2589,7 @@
   /// Note:
   /// This action invalidates case_end(). Old case_end() iterator will
   /// point to the added case.
-  void addCase(ConstantRangesSet& OnVal, BasicBlock *Dest);
+  void addCase(IntegersSubset& OnVal, BasicBlock *Dest);
 
   /// removeCase - This method removes the specified case and its successor
   /// from the switch instruction. Note that this operation may reorder the
@@ -2654,9 +2654,9 @@
     /// @Deprecated
     ConstantIntTy *getCaseValue() {
       assert(Index < SI->getNumCases() && "Index out the number of cases.");
-      ConstantRangesSet CRS =
+      IntegersSubset CaseRanges =
           reinterpret_cast<Constant*>(SI->getOperand(2 + Index*2));
-      ConstantRangesSet::Range R = CRS.getItem(0);
+      IntegersSubset::Range R = CaseRanges.getItem(0);
       
       // FIXME: Currently we work with ConstantInt based cases.
       // So return CaseValue as ConstantInt.
@@ -2664,7 +2664,7 @@
     }
 
     /// Resolves case value for current case.
-    ConstantRangesSet getCaseValueEx() {
+    IntegersSubset getCaseValueEx() {
       assert(Index < SI->getNumCases() && "Index out the number of cases.");
       return reinterpret_cast<Constant*>(SI->getOperand(2 + Index*2));
     }
@@ -2736,16 +2736,16 @@
     /// @Deprecated.
     void setValue(ConstantInt *V) {
       assert(Index < SI->getNumCases() && "Index out the number of cases.");
-      CRSBuilder CB;
+      IntegersSubsetToBB Mapping;
       // FIXME: Currently we work with ConstantInt based cases.
       // So inititalize IntItem container directly from ConstantInt.
-      CB.add(IntItem::fromConstantInt(V));
+      Mapping.add(IntItem::fromConstantInt(V));
       SI->setOperand(2 + Index*2,
-          reinterpret_cast<Value*>((Constant*)CB.getCase()));
+          reinterpret_cast<Value*>((Constant*)Mapping.getCase()));
     }
     
     /// Sets the new value for current case.
-    void setValueEx(ConstantRangesSet& V) {
+    void setValueEx(IntegersSubset& V) {
       assert(Index < SI->getNumCases() && "Index out the number of cases.");
       SI->setOperand(2 + Index*2, reinterpret_cast<Value*>((Constant*)V));      
     }
diff --git a/include/llvm/Support/ConstantRangesSet.h b/include/llvm/Support/IntegersSubset.h
similarity index 98%
rename from include/llvm/Support/ConstantRangesSet.h
rename to include/llvm/Support/IntegersSubset.h
index 109bd5b..894b104 100644
--- a/include/llvm/Support/ConstantRangesSet.h
+++ b/include/llvm/Support/IntegersSubset.h
@@ -223,14 +223,14 @@
 /// Note: It is assumed that "holder" is inherited from Constant object.
 ///       ConstantRangesSet may be converted to and from Constant* pointer.
 ///
-class ConstantRangesSet {
+class IntegersSubset {
   Constant *Array;
 public:
   
   bool IsWide;
   
   // implicit
-  ConstantRangesSet(Constant *V) : Array(V) {
+  IntegersSubset(Constant *V) : Array(V) {
     ArrayType *ArrTy = cast<ArrayType>(Array->getType());
     VectorType *VecTy = cast<VectorType>(ArrTy->getElementType());
     IntegerType *IntTy = cast<IntegerType>(VecTy->getElementType());
diff --git a/include/llvm/Support/CRSBuilder.h b/include/llvm/Support/IntegersSubsetMapping.h
similarity index 88%
rename from include/llvm/Support/CRSBuilder.h
rename to include/llvm/Support/IntegersSubsetMapping.h
index c5dfa9f..eaa2f5b 100644
--- a/include/llvm/Support/CRSBuilder.h
+++ b/include/llvm/Support/IntegersSubsetMapping.h
@@ -19,7 +19,7 @@
 #ifndef CRSBUILDER_H_
 #define CRSBUILDER_H_
 
-#include "llvm/Support/ConstantRangesSet.h"
+#include "llvm/Support/IntegersSubset.h"
 #include <list>
 #include <map>
 #include <vector>
@@ -27,13 +27,13 @@
 namespace llvm {
 
 template <class SuccessorClass>
-class CRSBuilderBase {
+class IntegersSubsetMapping {
 public:
   
-  typedef ConstantRangesSet::Range RangeTy;
+  typedef IntegersSubset::Range RangeTy;
   
   struct RangeEx : public RangeTy {
-    typedef ConstantRangesSet::Range RangeTy;
+    typedef IntegersSubset::Range RangeTy;
     RangeEx() : Weight(1) {}
     RangeEx(const RangeTy &R) : RangeTy(R.Low, R.High), Weight(1) {}
     RangeEx(const IntItem &C) : RangeTy(C), Weight(1) {}
@@ -50,6 +50,12 @@
   typedef std::vector<Cluster> CaseItems;
   typedef typename CaseItems::iterator CaseItemIt;
   typedef typename CaseItems::const_iterator CaseItemConstIt;
+  
+  typedef std::list<RangeTy> RangesCollection;
+  typedef typename RangesCollection::iterator RangesCollectionIt;
+  
+  typedef std::map<SuccessorClass*, RangesCollection > CRSMap;
+  typedef typename CRSMap::iterator CRSMapIt;
 
   struct ClustersCmp {
     bool operator()(const Cluster &C1, const Cluster &C2) {
@@ -82,6 +88,31 @@
       Sorted = true;
     }
   }
+
+  IntegersSubset getCase(RangesCollection& Src) {
+    std::vector<Constant*> Elts;
+    Elts.reserve(Src.size());
+    for (RangesCollectionIt i = Src.begin(), e = Src.end(); i != e; ++i) {
+      RangeTy &R = *i;
+      std::vector<Constant*> r;
+      if (R.isSingleNumber()) {
+        r.reserve(2);
+        // FIXME: Since currently we have ConstantInt based numbers
+        // use hack-conversion of IntItem to ConstantInt
+        r.push_back(R.Low.toConstantInt());
+        r.push_back(R.High.toConstantInt());
+      } else {
+        r.reserve(1);
+        r.push_back(R.Low.toConstantInt());
+      }
+      Constant *CV = ConstantVector::get(r);
+      Elts.push_back(CV);    
+    }
+    ArrayType *ArrTy =
+        ArrayType::get(Elts.front()->getType(), (uint64_t)Elts.size());
+    Constant *Array = ConstantArray::get(ArrTy, Elts);
+    return IntegersSubset(Array);     
+  }  
   
 public:
   
@@ -91,7 +122,10 @@
   // factory.
   typedef CaseItemIt RangeIterator;
   
-  CRSBuilderBase() {
+  typedef std::pair<SuccessorClass*, IntegersSubset> Case;
+  typedef std::list<Case> Cases;
+  
+  IntegersSubsetMapping() {
     Items.reserve(32);
     Sorted = false;
   }
@@ -164,7 +198,7 @@
   
   /// Adds all ranges and values from given ranges set to the current
   /// CRSBuilder object.
-  void add(const ConstantRangesSet &CRS, SuccessorClass *S = 0) {
+  void add(const IntegersSubset &CRS, SuccessorClass *S = 0) {
     for (unsigned i = 0, e = CRS.getNumItems(); i < e; ++i) {
       RangeTy R = CRS.getItem(i);
       add(R, S);
@@ -174,59 +208,6 @@
   /// Removes items from set.
   void removeItem(RangeIterator i) { Items.erase(i); }
   
-  /// Returns true if there is no ranges and values inside.
-  bool empty() const { return Items.empty(); }
-  
-  RangeIterator begin() { return Items.begin(); }
-  RangeIterator end() { return Items.end(); }
-};
-
-template <class SuccessorClass>
-class CRSBuilderT : public CRSBuilderBase<SuccessorClass> {
-public:
-  
-  typedef typename CRSBuilderBase<SuccessorClass>::RangeTy RangeTy;
-  typedef typename CRSBuilderBase<SuccessorClass>::RangeIterator
-      RangeIterator;
-  
-private:
-  
-  typedef std::list<RangeTy> RangesCollection;
-  typedef typename RangesCollection::iterator RangesCollectionIt;
-  
-  typedef std::map<SuccessorClass*, RangesCollection > CRSMap;
-  typedef typename CRSMap::iterator CRSMapIt;
-  
-  ConstantRangesSet getCase(RangesCollection& Src) {
-    std::vector<Constant*> Elts;
-    Elts.reserve(Src.size());
-    for (RangesCollectionIt i = Src.begin(), e = Src.end(); i != e; ++i) {
-      RangeTy &R = *i;
-      std::vector<Constant*> r;
-      if (R.isSingleNumber()) {
-        r.reserve(2);
-        // FIXME: Since currently we have ConstantInt based numbers
-        // use hack-conversion of IntItem to ConstantInt
-        r.push_back(R.Low.toConstantInt());
-        r.push_back(R.High.toConstantInt());
-      } else {
-        r.reserve(1);
-        r.push_back(R.Low.toConstantInt());
-      }
-      Constant *CV = ConstantVector::get(r);
-      Elts.push_back(CV);    
-    }
-    ArrayType *ArrTy =
-        ArrayType::get(Elts.front()->getType(), (uint64_t)Elts.size());
-    Constant *Array = ConstantArray::get(ArrTy, Elts);
-    return ConstantRangesSet(Array);     
-  }
-
-public:
-  
-  typedef std::pair<SuccessorClass*, ConstantRangesSet> Case;
-  typedef std::list<Case> Cases;
-  
   /// Builds the finalized case objects.
   void getCases(Cases& TheCases) {
     CRSMap TheCRSMap;
@@ -238,17 +219,22 @@
   
   /// Builds the finalized case objects ignoring successor values, as though
   /// all ranges belongs to the same successor.
-  ConstantRangesSet getCase() {
+  IntegersSubset getCase() {
     RangesCollection Ranges;
     for (RangeIterator i = this->begin(); i != this->end(); ++i)
       Ranges.push_back(i->first);
     return getCase(Ranges);
-  }
+  }  
+  
+  /// Returns true if there is no ranges and values inside.
+  bool empty() const { return Items.empty(); }
+  
+  RangeIterator begin() { return Items.begin(); }
+  RangeIterator end() { return Items.end(); }
 };
 
 class BasicBlock;
-typedef CRSBuilderT<BasicBlock> CRSBuilder;
-typedef CRSBuilderBase<BasicBlock> CRSBuilderConst;  
+typedef IntegersSubsetMapping<BasicBlock> IntegersSubsetToBB;
 
 }
 
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index e58af0e..83756da 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -2234,7 +2234,7 @@
         
         unsigned CurIdx = 5;
         for (unsigned i = 0; i != NumCases; ++i) {
-          CRSBuilder CaseBuilder;
+          IntegersSubsetToBB CaseBuilder;
           unsigned NumItems = Record[CurIdx++];
           for (unsigned ci = 0; ci != NumItems; ++ci) {
             bool isSingleNumber = Record[CurIdx++];
@@ -2262,7 +2262,7 @@
               CaseBuilder.add(IntItem::fromType(OpTy, Low));
           }
           BasicBlock *DestBB = getBasicBlock(Record[CurIdx++]);
-          ConstantRangesSet Case = CaseBuilder.getCase(); 
+          IntegersSubset Case = CaseBuilder.getCase(); 
           SI->addCase(Case, DestBB);
         }
         uint16_t Hash = SI->hash();
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index d454964..7dd18c8 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1157,12 +1157,12 @@
       Vals64.push_back(SI.getNumCases());
       for (SwitchInst::CaseIt i = SI.case_begin(), e = SI.case_end();
            i != e; ++i) {
-        ConstantRangesSet CRS = i.getCaseValueEx();
-        Vals64.push_back(CRS.getNumItems());
-        for (unsigned ri = 0, rn = CRS.getNumItems(); ri != rn; ++ri) {
-          ConstantRangesSet::Range r = CRS.getItem(ri);
+        IntegersSubset CaseRanges = i.getCaseValueEx();
+        Vals64.push_back(CaseRanges.getNumItems());
+        for (unsigned ri = 0, rn = CaseRanges.getNumItems(); ri != rn; ++ri) {
+          IntegersSubset::Range r = CaseRanges.getItem(ri);
 
-          Vals64.push_back(CRS.isSingleNumber(ri));
+          Vals64.push_back(CaseRanges.isSingleNumber(ri));
 
           const APInt &Low = r.Low;
           const APInt &High = r.High;
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index b7a6ec2..15c4258 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -51,7 +51,7 @@
 #include "llvm/Target/TargetLowering.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Support/CommandLine.h"
-#include "llvm/Support/CRSBuilder.h"
+#include "llvm/Support/IntegersSubsetMapping.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
@@ -2427,7 +2427,7 @@
   
   /// Use a shorter form of declaration, and also
   /// show the we want to use CRSBuilder as Clusterifier.
-  typedef CRSBuilderBase<MachineBasicBlock> Clusterifier;
+  typedef IntegersSubsetMapping<MachineBasicBlock> Clusterifier;
   
   Clusterifier TheClusterifier;
 
diff --git a/lib/ExecutionEngine/Interpreter/Execution.cpp b/lib/ExecutionEngine/Interpreter/Execution.cpp
index 46ed6fd..d540101 100644
--- a/lib/ExecutionEngine/Interpreter/Execution.cpp
+++ b/lib/ExecutionEngine/Interpreter/Execution.cpp
@@ -651,9 +651,9 @@
   // Check to see if any of the cases match...
   BasicBlock *Dest = 0;
   for (SwitchInst::CaseIt i = I.case_begin(), e = I.case_end(); i != e; ++i) {
-    ConstantRangesSet Case = i.getCaseValueEx();
+    IntegersSubset Case = i.getCaseValueEx();
     for (unsigned n = 0, en = Case.getNumItems(); n != en; ++n) {
-      ConstantRangesSet::Range r = Case.getItem(n);
+      IntegersSubset::Range r = Case.getItem(n);
       // FIXME: Currently work with ConstantInt based numbers.
       const ConstantInt *LowCI = r.Low.getImplementation();
       const ConstantInt *HighCI = r.High.getImplementation();
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index 9f95455..2ac9fe7 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -1105,7 +1105,7 @@
     nl(Out);
     for (SwitchInst::ConstCaseIt i = SI->case_begin(), e = SI->case_end();
          i != e; ++i) {
-      const ConstantRangesSet CaseVal = i.getCaseValueEx();
+      const IntegersSubset CaseVal = i.getCaseValueEx();
       const BasicBlock *BB = i.getCaseSuccessor();
       Out << iName << "->addCase("
           << getOpName(CaseVal) << ", "
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index 130b876..a4ddfa5 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -169,11 +169,11 @@
       // Otherwise, we can fold this switch into a conditional branch
       // instruction if it has only one non-default destination.
       SwitchInst::CaseIt FirstCase = SI->case_begin();
-      ConstantRangesSet CRS = FirstCase.getCaseValueEx();
-      if (CRS.getNumItems() == 1 && CRS.isSingleNumber(0)) {
+      IntegersSubset CaseRanges = FirstCase.getCaseValueEx();
+      if (CaseRanges.getNumItems() == 1 && CaseRanges.isSingleNumber(0)) {
         // FIXME: Currently work with ConstantInt based numbers.
         Value *Cond = Builder.CreateICmpEQ(SI->getCondition(),
-            CRS.getItem(0).Low.toConstantInt(),
+            CaseRanges.getItem(0).Low.toConstantInt(),
             "cond");
 
         // Insert the new branch.
diff --git a/lib/Transforms/Utils/LowerSwitch.cpp b/lib/Transforms/Utils/LowerSwitch.cpp
index 2362037..a4cf773 100644
--- a/lib/Transforms/Utils/LowerSwitch.cpp
+++ b/lib/Transforms/Utils/LowerSwitch.cpp
@@ -223,22 +223,22 @@
 // Clusterify - Transform simple list of Cases into list of CaseRange's
 unsigned LowerSwitch::Clusterify(CaseVector& Cases, SwitchInst *SI) {
 
-  CRSBuilder TheClusterifier;
+  IntegersSubsetToBB TheClusterifier;
 
   // Start with "simple" cases
   for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end();
        i != e; ++i) {
     BasicBlock *SuccBB = i.getCaseSuccessor();
-    ConstantRangesSet CRS = i.getCaseValueEx();
-    TheClusterifier.add(CRS, SuccBB);
+    IntegersSubset CaseRanges = i.getCaseValueEx();
+    TheClusterifier.add(CaseRanges, SuccBB);
   }
   
   TheClusterifier.optimize();
   
   size_t numCmps = 0;
-  for (CRSBuilder::RangeIterator i = TheClusterifier.begin(),
+  for (IntegersSubsetToBB::RangeIterator i = TheClusterifier.begin(),
        e = TheClusterifier.end(); i != e; ++i, ++numCmps) {
-    CRSBuilder::Cluster &C = *i;
+    IntegersSubsetToBB::Cluster &C = *i;
     
     // FIXME: Currently work with ConstantInt based numbers.
     // Changing it to APInt based is a pretty heavy for this commit.
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index 42a92d9..26cc632 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -3169,16 +3169,16 @@
 /// addCase - Add an entry to the switch instruction...
 ///
 void SwitchInst::addCase(ConstantInt *OnVal, BasicBlock *Dest) {
-  CRSBuilder CB;
+  IntegersSubsetToBB Mapping;
   
   // FIXME: Currently we work with ConstantInt based cases.
   // So inititalize IntItem container directly from ConstantInt.
-  CB.add(IntItem::fromConstantInt(OnVal));
-  ConstantRangesSet CRS = CB.getCase();
-  addCase(CRS, Dest);
+  Mapping.add(IntItem::fromConstantInt(OnVal));
+  IntegersSubset CaseRanges = Mapping.getCase();
+  addCase(CaseRanges, Dest);
 }
 
-void SwitchInst::addCase(ConstantRangesSet& OnVal, BasicBlock *Dest) {
+void SwitchInst::addCase(IntegersSubset& OnVal, BasicBlock *Dest) {
   unsigned NewCaseIdx = getNumCases(); 
   unsigned OpNo = NumOperands;
   if (OpNo+2 > ReservedSpace)
diff --git a/lib/VMCore/Verifier.cpp b/lib/VMCore/Verifier.cpp
index c546e41..cae3bc8 100644
--- a/lib/VMCore/Verifier.cpp
+++ b/lib/VMCore/Verifier.cpp
@@ -806,23 +806,23 @@
   // have the same type as the switched-on value.
   Type *SwitchTy = SI.getCondition()->getType();
   IntegerType *IntTy = cast<IntegerType>(SwitchTy);
-  CRSBuilder Builder;
-  std::map<ConstantRangesSet::Range, unsigned> RangeSetMap;
+  IntegersSubsetToBB Mapping;
+  std::map<IntegersSubset::Range, unsigned> RangeSetMap;
   for (SwitchInst::CaseIt i = SI.case_begin(), e = SI.case_end(); i != e; ++i) {
-    ConstantRangesSet RS = i.getCaseValueEx();
-    for (unsigned ri = 0, rie = RS.getNumItems(); ri < rie; ++ri) {
-      ConstantRangesSet::Range r = RS.getItem(ri);
+    IntegersSubset CaseRanges = i.getCaseValueEx();
+    for (unsigned ri = 0, rie = CaseRanges.getNumItems(); ri < rie; ++ri) {
+      IntegersSubset::Range r = CaseRanges.getItem(ri);
       Assert1(r.Low->getBitWidth() == IntTy->getBitWidth(),
               "Switch constants must all be same type as switch value!", &SI);
       Assert1(r.High->getBitWidth() == IntTy->getBitWidth(),
               "Switch constants must all be same type as switch value!", &SI);
-      Builder.add(r);
+      Mapping.add(r);
       RangeSetMap[r] = i.getCaseIndex();
     }
   }
   
-  CRSBuilder::RangeIterator errItem;
-  if (!Builder.verify(errItem)) {
+  IntegersSubsetToBB::RangeIterator errItem;
+  if (!Mapping.verify(errItem)) {
     unsigned CaseIndex = RangeSetMap[errItem->first];
     SwitchInst::CaseIt i(&SI, CaseIndex);
     Assert2(false, "Duplicate integer as switch case", &SI, i.getCaseValueEx());
diff --git a/tools/llvm-diff/DifferenceEngine.cpp b/tools/llvm-diff/DifferenceEngine.cpp
index 0e7815b..0c1e30c 100644
--- a/tools/llvm-diff/DifferenceEngine.cpp
+++ b/tools/llvm-diff/DifferenceEngine.cpp
@@ -326,7 +326,7 @@
         
       for (SwitchInst::CaseIt I = RI->case_begin(), E = RI->case_end();
            I != E; ++I) {
-        ConstantRangesSet CaseValue = I.getCaseValueEx();
+        IntegersSubset CaseValue = I.getCaseValueEx();
         BasicBlock *LCase = LCases[CaseValue];
         if (LCase) {
           if (TryUnify) tryUnify(LCase, I.getCaseSuccessor());