diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index a06a6f0..e399040 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -28,10 +28,6 @@
 #include "llvm/OperandTraits.h"
 using namespace llvm;
 
-enum {
-  SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
-};
-
 void BitcodeReader::materializeForwardReferencedFunctions() {
   while (!BlockAddrFwdRefs.empty()) {
     Function *F = BlockAddrFwdRefs.begin()->first;
@@ -981,17 +977,6 @@
   return false;
 }
 
-template <typename intty>
-APInt ReadWideAPInt(const intty *Vals, unsigned ActiveWords,
-                    unsigned TypeBits) {
-  SmallVector<uint64_t, 8> Words;
-  Words.resize(ActiveWords);
-  for (unsigned i = 0; i != ActiveWords; ++i)
-    Words[i] = DecodeSignRotatedValue(Vals[i]);
-  
-  return APInt(TypeBits, Words);
-}
-
 bool BitcodeReader::ParseConstants() {
   if (Stream.EnterSubBlock(bitc::CONSTANTS_BLOCK_ID))
     return Error("Malformed block record");
@@ -1048,11 +1033,13 @@
         return Error("Invalid WIDE_INTEGER record");
 
       unsigned NumWords = Record.size();
-      
-      APInt VInt = ReadWideAPInt(&Record[0], NumWords,
-          cast<IntegerType>(CurTy)->getBitWidth());
-      V = ConstantInt::get(Context, VInt);
-      
+      SmallVector<uint64_t, 8> Words;
+      Words.resize(NumWords);
+      for (unsigned i = 0; i != NumWords; ++i)
+        Words[i] = DecodeSignRotatedValue(Record[i]);
+      V = ConstantInt::get(Context,
+                           APInt(cast<IntegerType>(CurTy)->getBitWidth(),
+                                 Words));
       break;
     }
     case bitc::CST_CODE_FLOAT: {    // FLOAT: [fpval]
@@ -2284,61 +2271,6 @@
       break;
     }
     case bitc::FUNC_CODE_INST_SWITCH: { // SWITCH: [opty, op0, op1, ...]
-      // Check magic 
-      if ((Record[0] >> 16) == SWITCH_INST_MAGIC) {
-        // New SwitchInst format with case ranges.
-        
-        Type *OpTy = getTypeByID(Record[1]);
-        unsigned ValueBitWidth = cast<IntegerType>(OpTy)->getBitWidth();
-
-        Value *Cond = getFnValueByID(Record[2], OpTy);
-        BasicBlock *Default = getBasicBlock(Record[3]);
-        if (OpTy == 0 || Cond == 0 || Default == 0)
-          return Error("Invalid SWITCH record");
-
-        unsigned NumCases = Record[4];
-        
-        SwitchInst *SI = SwitchInst::Create(Cond, Default, NumCases);
-        
-        unsigned CurIdx = 5;
-        for (unsigned i = 0; i != NumCases; ++i) {
-          CRSBuilder CaseBuilder;
-          unsigned NumItems = Record[CurIdx++];
-          for (unsigned ci = 0; ci != NumItems; ++ci) {
-            bool isSingleNumber = Record[CurIdx++];
-            
-            APInt Low;
-            unsigned ActiveWords = 1;
-            if (ValueBitWidth > 64)
-              ActiveWords = Record[CurIdx++];
-            Low = ReadWideAPInt(&Record[CurIdx], ActiveWords, ValueBitWidth);
-            CurIdx += ActiveWords;
-            
-            if (!isSingleNumber) {
-              ActiveWords = 1;
-              if (ValueBitWidth > 64)
-                ActiveWords = Record[CurIdx++];
-              APInt High =
-                  ReadWideAPInt(&Record[CurIdx], ActiveWords, ValueBitWidth);
-              CaseBuilder.add(cast<ConstantInt>(ConstantInt::get(OpTy, Low)),
-                              cast<ConstantInt>(ConstantInt::get(OpTy, High)));
-              CurIdx += ActiveWords;
-            } else
-              CaseBuilder.add(cast<ConstantInt>(ConstantInt::get(OpTy, Low)));
-          }
-          BasicBlock *DestBB = getBasicBlock(Record[CurIdx++]);
-          ConstantRangesSet Case = CaseBuilder.getCase(); 
-          SI->addCase(Case, DestBB);
-        }
-        uint16_t Hash = SI->Hash();
-        if (Hash != (Record[0] & 0xFFFF))
-          return Error("Invalid SWITCH record");
-        I = SI;
-        break;
-      }
-      
-      // Old SwitchInst format without case ranges.
-      
       if (Record.size() < 3 || (Record.size() & 1) == 0)
         return Error("Invalid SWITCH record");
       Type *OpTy = getTypeByID(Record[0]);
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index f8065e3..b25d2e9 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -62,10 +62,7 @@
   FUNCTION_INST_CAST_ABBREV,
   FUNCTION_INST_RET_VOID_ABBREV,
   FUNCTION_INST_RET_VAL_ABBREV,
-  FUNCTION_INST_UNREACHABLE_ABBREV,
-  
-  // SwitchInst Magic
-  SWITCH_INST_MAGIC = 0x4B5 // May 2012 => 1205 => Hex
+  FUNCTION_INST_UNREACHABLE_ABBREV
 };
 
 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
@@ -722,42 +719,6 @@
   Stream.ExitBlock();
 }
 
-template <typename intty>
-static void EmitAPInt(SmallVectorImpl<intty> &Vals,
-                      unsigned &Code, unsigned &AbbrevToUse, const APInt &Val,
-                      bool EmitSizeForWideNumbers = false
-                      ) {
-  if (Val.getBitWidth() <= 64) {
-    uint64_t V = Val.getSExtValue();
-    if ((int64_t)V >= 0)
-      Vals.push_back(V << 1);
-    else
-      Vals.push_back((-V << 1) | 1);
-    Code = bitc::CST_CODE_INTEGER;
-    AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
-  } else {
-    // Wide integers, > 64 bits in size.
-    // We have an arbitrary precision integer value to write whose
-    // bit width is > 64. However, in canonical unsigned integer
-    // format it is likely that the high bits are going to be zero.
-    // So, we only write the number of active words.
-    unsigned NWords = Val.getActiveWords();
-    
-    if (EmitSizeForWideNumbers)
-      Vals.push_back(NWords);
-    
-    const uint64_t *RawWords = Val.getRawData();
-    for (unsigned i = 0; i != NWords; ++i) {
-      int64_t V = RawWords[i];
-      if (V >= 0)
-        Vals.push_back(V << 1);
-      else
-        Vals.push_back((-V << 1) | 1);
-    }
-    Code = bitc::CST_CODE_WIDE_INTEGER;
-  }
-}
-
 static void WriteConstants(unsigned FirstVal, unsigned LastVal,
                            const ValueEnumerator &VE,
                            BitstreamWriter &Stream, bool isGlobal) {
@@ -840,7 +801,30 @@
     } else if (isa<UndefValue>(C)) {
       Code = bitc::CST_CODE_UNDEF;
     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
-      EmitAPInt(Record, Code, AbbrevToUse, IV->getValue());
+      if (IV->getBitWidth() <= 64) {
+        uint64_t V = IV->getSExtValue();
+        if ((int64_t)V >= 0)
+          Record.push_back(V << 1);
+        else
+          Record.push_back((-V << 1) | 1);
+        Code = bitc::CST_CODE_INTEGER;
+        AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
+      } else {                             // Wide integers, > 64 bits in size.
+        // We have an arbitrary precision integer value to write whose
+        // bit width is > 64. However, in canonical unsigned integer
+        // format it is likely that the high bits are going to be zero.
+        // So, we only write the number of active words.
+        unsigned NWords = IV->getValue().getActiveWords();
+        const uint64_t *RawWords = IV->getValue().getRawData();
+        for (unsigned i = 0; i != NWords; ++i) {
+          int64_t V = RawWords[i];
+          if (V >= 0)
+            Record.push_back(V << 1);
+          else
+            Record.push_back((-V << 1) | 1);
+        }
+        Code = bitc::CST_CODE_WIDE_INTEGER;
+      }
     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
       Code = bitc::CST_CODE_FLOAT;
       Type *Ty = CFP->getType();
@@ -1155,31 +1139,12 @@
     {
       Code = bitc::FUNC_CODE_INST_SWITCH;
       SwitchInst &SI = cast<SwitchInst>(I);
-      
-      uint32_t SwitchRecordHeader = SI.Hash() | (SWITCH_INST_MAGIC << 16); 
-      Vals.push_back(SwitchRecordHeader);      
-      
       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
       Vals.push_back(VE.getValueID(SI.getCondition()));
       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
-      Vals.push_back(SI.getNumCases());
       for (SwitchInst::CaseIt i = SI.case_begin(), e = SI.case_end();
            i != e; ++i) {
-        ConstantRangesSet CRS = i.getCaseValueEx();
-        Vals.push_back(CRS.getNumItems());
-        for (unsigned ri = 0, rn = CRS.getNumItems(); ri != rn; ++ri) {
-          ConstantRangesSet::Range r = CRS.getItem(ri);
-
-          Vals.push_back(CRS.isSingleNumber(ri));
-
-          const APInt &Low = r.Low->getValue();
-          const APInt &High = r.High->getValue();
-          unsigned Code, Abbrev; // will unused.
-          
-          EmitAPInt(Vals, Code, Abbrev, Low, true);
-          if (r.Low != r.High)
-            EmitAPInt(Vals, Code, Abbrev, High, true);
-        }
+        Vals.push_back(VE.getValueID(i.getCaseValue()));
         Vals.push_back(VE.getValueID(i.getCaseSuccessor()));
       }
     }