diff --git a/include/llvm/Analysis/ScalarEvolutionExpressions.h b/include/llvm/Analysis/ScalarEvolutionExpressions.h
index e87d063..fc03e9f 100644
--- a/include/llvm/Analysis/ScalarEvolutionExpressions.h
+++ b/include/llvm/Analysis/ScalarEvolutionExpressions.h
@@ -15,6 +15,7 @@
 #define LLVM_ANALYSIS_SCALAREVOLUTION_EXPRESSIONS_H
 
 #include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Support/ErrorHandling.h"
 
 namespace llvm {
   class ConstantInt;
@@ -584,14 +585,12 @@
       case scCouldNotCompute:
         return ((SC*)this)->visitCouldNotCompute((const SCEVCouldNotCompute*)S);
       default:
-        assert(0 && "Unknown SCEV type!");
-        abort();
+        LLVM_UNREACHABLE("Unknown SCEV type!");
       }
     }
 
     RetVal visitCouldNotCompute(const SCEVCouldNotCompute *S) {
-      assert(0 && "Invalid use of SCEVCouldNotCompute!");
-      abort();
+      LLVM_UNREACHABLE("Invalid use of SCEVCouldNotCompute!");
       return RetVal();
     }
   };
diff --git a/include/llvm/MDNode.h b/include/llvm/MDNode.h
index d632e4e..dcda5d0 100644
--- a/include/llvm/MDNode.h
+++ b/include/llvm/MDNode.h
@@ -25,6 +25,7 @@
 #include "llvm/Type.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ValueHandle.h"
 
 namespace llvm {
@@ -119,8 +120,7 @@
 
   virtual void destroyConstant();
   virtual void replaceUsesOfWithOnConstant(Value *From, Value *To, Use *U) {
-    assert(0 && "This should never be called because MDNodes have no ops");
-    abort();
+    LLVM_UNREACHABLE("This should never be called because MDNodes have no ops");
   }
 
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
diff --git a/include/llvm/Support/ErrorHandling.h b/include/llvm/Support/ErrorHandling.h
index c7e4297..1a401eb 100644
--- a/include/llvm/Support/ErrorHandling.h
+++ b/include/llvm/Support/ErrorHandling.h
@@ -46,11 +46,11 @@
   /// This function calls abort().
   /// Call this after assert(0), so that compiler knows the path is not
   /// reachable.
-  void llvm_unreachable(void) NORETURN;
+  void llvm_unreachable(const char *msg=0) NORETURN;
 }
 
 #ifndef NDEBUG
-#define LLVM_UNREACHABLE(msg) do {cerr<<msg<<"\n";llvm_unreachable();}while(0)
+#define LLVM_UNREACHABLE(msg) llvm_unreachable(msg)
 #else
 #define LLVM_UNREACHABLE(msg) llvm_unreachable()
 #endif
diff --git a/include/llvm/Support/InstVisitor.h b/include/llvm/Support/InstVisitor.h
index 768f487..2fa8c47 100644
--- a/include/llvm/Support/InstVisitor.h
+++ b/include/llvm/Support/InstVisitor.h
@@ -14,6 +14,7 @@
 #include "llvm/Function.h"
 #include "llvm/Instructions.h"
 #include "llvm/Module.h"
+#include "llvm/Support/ErrorHandling.h"
 
 namespace llvm {
 
@@ -113,8 +114,7 @@
   //
   RetTy visit(Instruction &I) {
     switch (I.getOpcode()) {
-    default: assert(0 && "Unknown instruction type encountered!");
-             abort();
+    default: LLVM_UNREACHABLE("Unknown instruction type encountered!");
       // Build the switch statement using the Instruction.def file...
 #define HANDLE_INST(NUM, OPCODE, CLASS) \
     case Instruction::OPCODE: return \
diff --git a/include/llvm/Support/PassNameParser.h b/include/llvm/Support/PassNameParser.h
index e489e0a..12c1240 100644
--- a/include/llvm/Support/PassNameParser.h
+++ b/include/llvm/Support/PassNameParser.h
@@ -24,6 +24,7 @@
 #define LLVM_SUPPORT_PASS_NAME_PARSER_H
 
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Pass.h"
 #include <algorithm>
 #include <cstring>
@@ -67,7 +68,7 @@
     if (findOption(P->getPassArgument()) != getNumOptions()) {
       cerr << "Two passes with the same argument (-"
            << P->getPassArgument() << ") attempted to be registered!\n";
-      abort();
+      llvm_unreachable();
     }
     addLiteralOption(P->getPassArgument(), P, P->getPassName());
   }
diff --git a/include/llvm/Target/TargetData.h b/include/llvm/Target/TargetData.h
index 82abfc7..c06165c 100644
--- a/include/llvm/Target/TargetData.h
+++ b/include/llvm/Target/TargetData.h
@@ -22,6 +22,7 @@
 
 #include "llvm/Pass.h"
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/ADT/SmallVector.h"
 #include <string>
 
@@ -111,9 +112,8 @@
   /// @note This has to exist, because this is a pass, but it should never be
   /// used.
   TargetData() : ImmutablePass(&ID) {
-    assert(0 && "ERROR: Bad TargetData ctor used.  "
-           "Tool did not specify a TargetData to use?");
-    abort();
+    llvm_report_error("ERROR: Bad TargetData ctor used.  "
+                      "Tool did not specify a TargetData to use?");
   }
 
   /// Constructs a TargetData from a specification string. See init().
diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index 0635c23..242bbdc 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -14,6 +14,7 @@
 #ifndef LLVM_TARGET_TARGETINSTRINFO_H
 #define LLVM_TARGET_TARGETINSTRINFO_H
 
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetInstrDesc.h"
 #include "llvm/CodeGen/MachineFunction.h"
 
@@ -428,8 +429,7 @@
   /// point.
   virtual void insertNoop(MachineBasicBlock &MBB, 
                           MachineBasicBlock::iterator MI) const {
-    assert(0 && "Target didn't implement insertNoop!");
-    abort();
+    LLVM_UNREACHABLE("Target didn't implement insertNoop!");
   }
 
   /// isPredicated - Returns true if the instruction is already predicated.
diff --git a/lib/Analysis/AliasAnalysisCounter.cpp b/lib/Analysis/AliasAnalysisCounter.cpp
index 4362d7d..2ed11ac 100644
--- a/lib/Analysis/AliasAnalysisCounter.cpp
+++ b/lib/Analysis/AliasAnalysisCounter.cpp
@@ -18,6 +18,7 @@
 #include "llvm/Assembly/Writer.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Streams.h"
 using namespace llvm;
 
@@ -131,7 +132,7 @@
 
   const char *AliasString;
   switch (R) {
-  default: assert(0 && "Unknown alias type!");
+  default: LLVM_UNREACHABLE("Unknown alias type!");
   case NoAlias:   No++;   AliasString = "No alias"; break;
   case MayAlias:  May++;  AliasString = "May alias"; break;
   case MustAlias: Must++; AliasString = "Must alias"; break;
@@ -156,7 +157,7 @@
 
   const char *MRString;
   switch (R) {
-  default:       assert(0 && "Unknown mod/ref type!");
+  default:       LLVM_UNREACHABLE("Unknown mod/ref type!");
   case NoModRef: NoMR++;     MRString = "NoModRef"; break;
   case Ref:      JustRef++;  MRString = "JustRef"; break;
   case Mod:      JustMod++;  MRString = "JustMod"; break;
diff --git a/lib/Analysis/AliasSetTracker.cpp b/lib/Analysis/AliasSetTracker.cpp
index 18c2b66..7ba98dd 100644
--- a/lib/Analysis/AliasSetTracker.cpp
+++ b/lib/Analysis/AliasSetTracker.cpp
@@ -20,6 +20,7 @@
 #include "llvm/Target/TargetData.h"
 #include "llvm/Assembly/Writer.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/InstIterator.h"
 #include "llvm/Support/Streams.h"
 using namespace llvm;
@@ -539,7 +540,7 @@
   case Refs    : OS << "Ref       "; break;
   case Mods    : OS << "Mod       "; break;
   case ModRef  : OS << "Mod/Ref   "; break;
-  default: assert(0 && "Bad value for AccessTy!");
+  default: LLVM_UNREACHABLE("Bad value for AccessTy!");
   }
   if (isVolatile()) OS << "[volatile] ";
   if (Forward)
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index c474fe7..daa3c9a 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -28,6 +28,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/GetElementPtrTypeIterator.h"
 #include <algorithm>
 using namespace llvm;
@@ -157,7 +158,7 @@
 
     virtual void getArgumentAccesses(Function *F, CallSite CS,
                                      std::vector<PointerAccessInfo> &Info) {
-      assert(0 && "This method may not be called on this function!");
+      LLVM_UNREACHABLE("This method may not be called on this function!");
     }
 
     virtual void getMustAliases(Value *P, std::vector<Value*> &RetVals) { }
diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index ffdc52c..7e6b877 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -23,6 +23,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/Target/TargetData.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Support/MathExtras.h"
 #include <cerrno>
@@ -365,7 +366,7 @@
     return 0;
   case Instruction::ICmp:
   case Instruction::FCmp:
-    assert(0 &&"This function is invalid for compares: no predicate specified");
+    LLVM_UNREACHABLE("This function is invalid for compares: no predicate specified");
   case Instruction::PtrToInt:
     // If the input is a inttoptr, eliminate the pair.  This requires knowing
     // the width of a pointer, so it can't be done in ConstantExpr::getCast.
@@ -690,7 +691,7 @@
     return Context->getConstantFP(APFloat((float)V));
   if (Ty == Type::DoubleTy)
     return Context->getConstantFP(APFloat(V));
-  assert(0 && "Can only constant fold float/double");
+  LLVM_UNREACHABLE("Can only constant fold float/double");
   return 0; // dummy return to suppress warning
 }
 
@@ -709,7 +710,7 @@
     return Context->getConstantFP(APFloat((float)V));
   if (Ty == Type::DoubleTy)
     return Context->getConstantFP(APFloat(V));
-  assert(0 && "Can only constant fold float/double");
+  LLVM_UNREACHABLE("Can only constant fold float/double");
   return 0; // dummy return to suppress warning
 }
 
diff --git a/lib/Analysis/IPA/Andersens.cpp b/lib/Analysis/IPA/Andersens.cpp
index f453a6f..3f1dcb7 100644
--- a/lib/Analysis/IPA/Andersens.cpp
+++ b/lib/Analysis/IPA/Andersens.cpp
@@ -508,7 +508,7 @@
 #ifndef NDEBUG
         V->dump();
 #endif
-        assert(0 && "Value does not have a node in the points-to graph!");
+        LLVM_UNREACHABLE("Value does not have a node in the points-to graph!");
       }
       return I->second;
     }
@@ -827,10 +827,10 @@
       return getNodeForConstantPointer(CE->getOperand(0));
     default:
       cerr << "Constant Expr not yet handled: " << *CE << "\n";
-      assert(0);
+      llvm_unreachable();
     }
   } else {
-    assert(0 && "Unknown constant pointer!");
+    LLVM_UNREACHABLE("Unknown constant pointer!");
   }
   return 0;
 }
@@ -854,10 +854,10 @@
       return getNodeForConstantPointerTarget(CE->getOperand(0));
     default:
       cerr << "Constant Expr not yet handled: " << *CE << "\n";
-      assert(0);
+      llvm_unreachable();
     }
   } else {
-    assert(0 && "Unknown constant pointer!");
+    LLVM_UNREACHABLE("Unknown constant pointer!");
   }
   return 0;
 }
@@ -1244,7 +1244,7 @@
 }
 
 void Andersens::visitVAArg(VAArgInst &I) {
-  assert(0 && "vaarg not handled yet!");
+  LLVM_UNREACHABLE("vaarg not handled yet!");
 }
 
 /// AddConstraintsForCall - Add constraints for a call with actual arguments
diff --git a/lib/Analysis/LoopDependenceAnalysis.cpp b/lib/Analysis/LoopDependenceAnalysis.cpp
index f605783..79f92a6 100644
--- a/lib/Analysis/LoopDependenceAnalysis.cpp
+++ b/lib/Analysis/LoopDependenceAnalysis.cpp
@@ -24,6 +24,7 @@
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Instructions.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetData.h"
 using namespace llvm;
 
@@ -63,7 +64,7 @@
     return i->getPointerOperand();
   if (StoreInst *i = dyn_cast<StoreInst>(I))
     return i->getPointerOperand();
-  assert(0 && "Value is no load or store instruction!");
+  LLVM_UNREACHABLE("Value is no load or store instruction!");
   // Never reached.
   return 0;
 }
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index a9528cf..86a7613 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -75,6 +75,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/ConstantRange.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Support/InstIterator.h"
 #include "llvm/Support/MathExtras.h"
@@ -147,21 +148,21 @@
   SCEV(scCouldNotCompute) {}
 
 void SCEVCouldNotCompute::Profile(FoldingSetNodeID &ID) const {
-  assert(0 && "Attempt to use a SCEVCouldNotCompute object!");
+  LLVM_UNREACHABLE("Attempt to use a SCEVCouldNotCompute object!");
 }
 
 bool SCEVCouldNotCompute::isLoopInvariant(const Loop *L) const {
-  assert(0 && "Attempt to use a SCEVCouldNotCompute object!");
+  LLVM_UNREACHABLE("Attempt to use a SCEVCouldNotCompute object!");
   return false;
 }
 
 const Type *SCEVCouldNotCompute::getType() const {
-  assert(0 && "Attempt to use a SCEVCouldNotCompute object!");
+  LLVM_UNREACHABLE("Attempt to use a SCEVCouldNotCompute object!");
   return 0;
 }
 
 bool SCEVCouldNotCompute::hasComputableLoopEvolution(const Loop *L) const {
-  assert(0 && "Attempt to use a SCEVCouldNotCompute object!");
+  LLVM_UNREACHABLE("Attempt to use a SCEVCouldNotCompute object!");
   return false;
 }
 
@@ -296,7 +297,7 @@
       else if (isa<SCEVUMaxExpr>(this))
         return SE.getUMaxExpr(NewOps);
       else
-        assert(0 && "Unknown commutative expr!");
+        LLVM_UNREACHABLE("Unknown commutative expr!");
     }
   }
   return this;
@@ -543,7 +544,7 @@
         return operator()(LC->getOperand(), RC->getOperand());
       }
 
-      assert(0 && "Unknown SCEV kind!");
+      LLVM_UNREACHABLE("Unknown SCEV kind!");
       return false;
     }
   };
@@ -3488,7 +3489,7 @@
         if (Idx >= ATy->getNumElements()) return 0;  // Bogus program
         Init = Constant::getNullValue(ATy->getElementType());
       } else {
-        assert(0 && "Unknown constant aggregate type!");
+        LLVM_UNREACHABLE("Unknown constant aggregate type!");
       }
       return 0;
     } else {
@@ -3898,7 +3899,7 @@
           return getSMaxExpr(NewOps);
         if (isa<SCEVUMaxExpr>(Comm))
           return getUMaxExpr(NewOps);
-        assert(0 && "Unknown commutative SCEV type!");
+        LLVM_UNREACHABLE("Unknown commutative SCEV type!");
       }
     }
     // If we got here, all operands are loop invariant.
@@ -3949,7 +3950,7 @@
     return getTruncateExpr(Op, Cast->getType());
   }
 
-  assert(0 && "Unknown SCEV type!");
+  LLVM_UNREACHABLE("Unknown SCEV type!");
   return 0;
 }
 
@@ -4260,7 +4261,7 @@
 
   switch (Pred) {
   default:
-    assert(0 && "Unexpected ICmpInst::Predicate value!");
+    LLVM_UNREACHABLE("Unexpected ICmpInst::Predicate value!");
     break;
   case ICmpInst::ICMP_SGT:
     Pred = ICmpInst::ICMP_SLT;
diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index 10e5a60..c854031 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -15,6 +15,7 @@
 #include "llvm/DerivedTypes.h"
 #include "llvm/Instruction.h"
 #include "llvm/LLVMContext.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/SourceMgr.h"
@@ -699,7 +700,7 @@
 
   uint64_t Pair[2];
   switch (Kind) {
-  default: assert(0 && "Unknown kind!");
+  default: LLVM_UNREACHABLE("Unknown kind!");
   case 'K':
     // F80HexFPConstant - x87 long double in hexadecimal format (10 bytes)
     FP80HexToIntPair(TokStart+3, CurPtr, Pair);
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 64212f6..fca2460 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -24,6 +24,7 @@
 #include "llvm/ValueSymbolTable.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
@@ -2040,7 +2041,7 @@
     return Error(ID.Loc, "functions are not values, refer to them as pointers");
   
   switch (ID.Kind) {
-  default: assert(0 && "Unknown ValID!");
+  default: LLVM_UNREACHABLE("Unknown ValID!");
   case ValID::t_LocalID:
   case ValID::t_LocalName:
     return Error(ID.Loc, "invalid use of function-local name");
@@ -2835,7 +2836,7 @@
 
   bool Valid;
   switch (OperandType) {
-  default: assert(0 && "Unknown operand type!");
+  default: LLVM_UNREACHABLE("Unknown operand type!");
   case 0: // int or FP.
     Valid = LHS->getType()->isIntOrIntVector() ||
             LHS->getType()->isFPOrFPVector();
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 1f3fd55..18f3262 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -23,6 +23,7 @@
 #include "llvm/Module.h"
 #include "llvm/TypeSymbolTable.h"
 #include "llvm/ValueSymbolTable.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Streams.h"
 #include "llvm/Support/raw_ostream.h"
@@ -58,7 +59,7 @@
 
 static unsigned GetEncodedCastOpcode(unsigned Opcode) {
   switch (Opcode) {
-  default: assert(0 && "Unknown cast instruction!");
+  default: LLVM_UNREACHABLE("Unknown cast instruction!");
   case Instruction::Trunc   : return bitc::CAST_TRUNC;
   case Instruction::ZExt    : return bitc::CAST_ZEXT;
   case Instruction::SExt    : return bitc::CAST_SEXT;
@@ -76,7 +77,7 @@
 
 static unsigned GetEncodedBinaryOpcode(unsigned Opcode) {
   switch (Opcode) {
-  default: assert(0 && "Unknown binary instruction!");
+  default: LLVM_UNREACHABLE("Unknown binary instruction!");
   case Instruction::Add:
   case Instruction::FAdd: return bitc::BINOP_ADD;
   case Instruction::Sub:
@@ -200,7 +201,7 @@
     unsigned Code = 0;
     
     switch (T->getTypeID()) {
-    default: assert(0 && "Unknown type!");
+    default: LLVM_UNREACHABLE("Unknown type!");
     case Type::VoidTyID:   Code = bitc::TYPE_CODE_VOID;   break;
     case Type::FloatTyID:  Code = bitc::TYPE_CODE_FLOAT;  break;
     case Type::DoubleTyID: Code = bitc::TYPE_CODE_DOUBLE; break;
@@ -278,7 +279,7 @@
 
 static unsigned getEncodedLinkage(const GlobalValue *GV) {
   switch (GV->getLinkage()) {
-  default: assert(0 && "Invalid linkage!");
+  default: LLVM_UNREACHABLE("Invalid linkage!");
   case GlobalValue::GhostLinkage:  // Map ghost linkage onto external.
   case GlobalValue::ExternalLinkage:     return 0;
   case GlobalValue::WeakAnyLinkage:      return 1;
@@ -298,7 +299,7 @@
 
 static unsigned getEncodedVisibility(const GlobalValue *GV) {
   switch (GV->getVisibility()) {
-  default: assert(0 && "Invalid visibility!");
+  default: LLVM_UNREACHABLE("Invalid visibility!");
   case GlobalValue::DefaultVisibility:   return 0;
   case GlobalValue::HiddenVisibility:    return 1;
   case GlobalValue::ProtectedVisibility: return 2;
@@ -712,7 +713,7 @@
         }
       }
     } else {
-      assert(0 && "Unknown constant!");
+      LLVM_UNREACHABLE("Unknown constant!");
     }
     Stream.EmitRecord(Code, Record, AbbrevToUse);
     Record.clear();
@@ -1126,7 +1127,7 @@
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, 
                                    Abbv) != VST_ENTRY_8_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   
   { // 7-bit fixed width VST_ENTRY strings.
@@ -1137,7 +1138,7 @@
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
                                    Abbv) != VST_ENTRY_7_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   { // 6-bit char6 VST_ENTRY strings.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
@@ -1147,7 +1148,7 @@
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
                                    Abbv) != VST_ENTRY_6_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   { // 6-bit char6 VST_BBENTRY strings.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
@@ -1157,7 +1158,7 @@
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID,
                                    Abbv) != VST_BBENTRY_6_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   
   
@@ -1169,7 +1170,7 @@
                               Log2_32_Ceil(VE.getTypes().size()+1)));
     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
                                    Abbv) != CONSTANTS_SETTYPE_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   
   { // INTEGER abbrev for CONSTANTS_BLOCK.
@@ -1178,7 +1179,7 @@
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
                                    Abbv) != CONSTANTS_INTEGER_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   
   { // CE_CAST abbrev for CONSTANTS_BLOCK.
@@ -1191,14 +1192,14 @@
 
     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
                                    Abbv) != CONSTANTS_CE_CAST_Abbrev)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   { // NULL abbrev for CONSTANTS_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID,
                                    Abbv) != CONSTANTS_NULL_Abbrev)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   
   // FIXME: This should only use space for first class types!
@@ -1211,7 +1212,7 @@
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_LOAD_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   { // INST_BINOP abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
@@ -1221,7 +1222,7 @@
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_BINOP_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   { // INST_CAST abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
@@ -1232,7 +1233,7 @@
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_CAST_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   
   { // INST_RET abbrev for FUNCTION_BLOCK.
@@ -1240,7 +1241,7 @@
     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_RET_VOID_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   { // INST_RET abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
@@ -1248,14 +1249,14 @@
     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_RET_VAL_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID,
                                    Abbv) != FUNCTION_INST_UNREACHABLE_ABBREV)
-      assert(0 && "Unexpected abbrev ordering!");
+      LLVM_UNREACHABLE("Unexpected abbrev ordering!");
   }
   
   Stream.ExitBlock();
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index daa4a70..ea27490 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -237,7 +237,7 @@
       else if (I->hasWeakLinkage())
         O << TAI->getWeakRefDirective() << Name << '\n';
       else if (!I->hasLocalLinkage())
-        assert(0 && "Invalid alias linkage");
+        LLVM_UNREACHABLE("Invalid alias linkage");
 
       printVisibility(Name, I->getVisibility());
 
@@ -901,7 +901,7 @@
     case Instruction::SIToFP:
     case Instruction::FPToUI:
     case Instruction::FPToSI:
-      assert(0 && "FIXME: Don't yet support this kind of constant cast expr");
+      LLVM_UNREACHABLE("FIXME: Don't yet support this kind of constant cast expr");
       break;
     case Instruction::BitCast:
       return EmitConstantValueOnly(CE->getOperand(0));
@@ -967,10 +967,10 @@
       O << ')';
       break;
     default:
-      assert(0 && "Unsupported operator!");
+      LLVM_UNREACHABLE("Unsupported operator!");
     }
   } else {
-    assert(0 && "Unknown constant value!");
+    LLVM_UNREACHABLE("Unknown constant value!");
   }
 }
 
@@ -1209,7 +1209,7 @@
       O << '\n';
     }
     return;
-  } else assert(0 && "Floating point constant type not handled");
+  } else LLVM_UNREACHABLE("Floating point constant type not handled");
 }
 
 void AsmPrinter::EmitGlobalConstantLargeInt(const ConstantInt *CI,
@@ -1660,7 +1660,7 @@
              "Target cannot handle 64-bit constant exprs!");
       O << TAI->getData64bitsDirective(AddrSpace);
     } else {
-      assert(0 && "Target cannot handle given data directive width!");
+      LLVM_UNREACHABLE("Target cannot handle given data directive width!");
     }
     break;
   }
diff --git a/lib/CodeGen/AsmPrinter/DIE.cpp b/lib/CodeGen/AsmPrinter/DIE.cpp
index 01c431c..dd61ca3 100644
--- a/lib/CodeGen/AsmPrinter/DIE.cpp
+++ b/lib/CodeGen/AsmPrinter/DIE.cpp
@@ -16,6 +16,7 @@
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/Target/TargetAsmInfo.h"
 #include "llvm/Target/TargetData.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <ostream>
 using namespace llvm;
 
@@ -206,7 +207,7 @@
   case dwarf::DW_FORM_data8: Asm->EmitInt64(Integer);        break;
   case dwarf::DW_FORM_udata: Asm->EmitULEB128Bytes(Integer); break;
   case dwarf::DW_FORM_sdata: Asm->EmitSLEB128Bytes(Integer); break;
-  default: assert(0 && "DIE Value form not supported yet");  break;
+  default: LLVM_UNREACHABLE("DIE Value form not supported yet");
   }
 }
 
@@ -225,7 +226,7 @@
   case dwarf::DW_FORM_data8: return sizeof(int64_t);
   case dwarf::DW_FORM_udata: return TargetAsmInfo::getULEB128Size(Integer);
   case dwarf::DW_FORM_sdata: return TargetAsmInfo::getSLEB128Size(Integer);
-  default: assert(0 && "DIE Value form not supported yet"); break;
+  default: LLVM_UNREACHABLE("DIE Value form not supported yet"); break;
   }
   return 0;
 }
@@ -481,7 +482,7 @@
   case dwarf::DW_FORM_block2: Asm->EmitInt16(Size);        break;
   case dwarf::DW_FORM_block4: Asm->EmitInt32(Size);        break;
   case dwarf::DW_FORM_block:  Asm->EmitULEB128Bytes(Size); break;
-  default: assert(0 && "Improper form for block");         break;
+  default: LLVM_UNREACHABLE("Improper form for block");         break;
   }
 
   const SmallVector<DIEAbbrevData, 8> &AbbrevData = Abbrev.getData();
@@ -499,7 +500,7 @@
   case dwarf::DW_FORM_block2: return Size + sizeof(int16_t);
   case dwarf::DW_FORM_block4: return Size + sizeof(int32_t);
   case dwarf::DW_FORM_block: return Size + TargetAsmInfo::getULEB128Size(Size);
-  default: assert(0 && "Improper form for block"); break;
+  default: LLVM_UNREACHABLE("Improper form for block"); break;
   }
   return 0;
 }
diff --git a/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp b/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp
index a1b97df..be274ca 100644
--- a/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp
@@ -17,6 +17,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/Support/Dwarf.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetAsmInfo.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetFrameInfo.h"
@@ -190,7 +191,7 @@
         Asm->EmitULEB128Bytes(Offset);
         Asm->EOL("Offset");
       } else {
-        assert(0 && "Machine move not supported yet.");
+        LLVM_UNREACHABLE("Machine move not supported yet.");
       }
     } else if (Src.isReg() &&
                Src.getReg() == MachineLocation::VirtualFP) {
@@ -200,7 +201,7 @@
         Asm->EmitULEB128Bytes(RI->getDwarfRegNum(Dst.getReg(), isEH));
         Asm->EOL("Register");
       } else {
-        assert(0 && "Machine move not supported yet.");
+        LLVM_UNREACHABLE("Machine move not supported yet.");
       }
     } else {
       unsigned Reg = RI->getDwarfRegNum(Src.getReg(), isEH);
diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index 2635303..c839b3e 100644
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/STLExtras.h"
@@ -461,7 +462,7 @@
       // _GLIBCXX_DEBUG checks strict weak ordering, which involves comparing
       // an object with itself.
 #ifndef _GLIBCXX_DEBUG
-      assert(0 && "Predecessor appears twice");
+      LLVM_UNREACHABLE("Predecessor appears twice");
 #endif
       return false;
     }
diff --git a/lib/CodeGen/ELFCodeEmitter.cpp b/lib/CodeGen/ELFCodeEmitter.cpp
index 78f0dae..07aa1cb 100644
--- a/lib/CodeGen/ELFCodeEmitter.cpp
+++ b/lib/CodeGen/ELFCodeEmitter.cpp
@@ -23,6 +23,7 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetAsmInfo.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 
 //===----------------------------------------------------------------------===//
 //                       ELFCodeEmitter Implementation
@@ -107,7 +108,7 @@
       MR.setResultPointer((void*)Addr);
       MR.setConstantVal(JumpTableSectionIdx);
     } else {
-      assert(0 && "Unhandled relocation type");
+      LLVM_UNREACHABLE("Unhandled relocation type");
     }
     ES->addRelocation(MR);
   }
diff --git a/lib/CodeGen/ELFWriter.cpp b/lib/CodeGen/ELFWriter.cpp
index ddc3670..1318017 100644
--- a/lib/CodeGen/ELFWriter.cpp
+++ b/lib/CodeGen/ELFWriter.cpp
@@ -51,6 +51,7 @@
 #include "llvm/Support/Streams.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 
 using namespace llvm;
 
@@ -147,7 +148,7 @@
 unsigned ELFWriter::getGlobalELFVisibility(const GlobalValue *GV) {
   switch (GV->getVisibility()) {
   default:
-    assert(0 && "unknown visibility type");
+    LLVM_UNREACHABLE("unknown visibility type");
   case GlobalValue::DefaultVisibility:
     return ELFSym::STV_DEFAULT;
   case GlobalValue::HiddenVisibility:
@@ -339,9 +340,9 @@
     else if (CFP->getType() == Type::FloatTy)
       GblS.emitWord32(Val);
     else if (CFP->getType() == Type::X86_FP80Ty) {
-      assert(0 && "X86_FP80Ty global emission not implemented");
+      LLVM_UNREACHABLE("X86_FP80Ty global emission not implemented");
     } else if (CFP->getType() == Type::PPC_FP128Ty)
-      assert(0 && "PPC_FP128Ty global emission not implemented");
+      LLVM_UNREACHABLE("PPC_FP128Ty global emission not implemented");
     return;
   } else if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
     if (Size == 4)
@@ -349,7 +350,7 @@
     else if (Size == 8)
       GblS.emitWord64(CI->getZExtValue());
     else
-      assert(0 && "LargeInt global emission not implemented");
+      LLVM_UNREACHABLE("LargeInt global emission not implemented");
     return;
   } else if (const ConstantVector *CP = dyn_cast<ConstantVector>(CV)) {
     const VectorType *PTy = CP->getType();
@@ -357,7 +358,7 @@
       EmitGlobalConstant(CP->getOperand(I), GblS);
     return;
   }
-  assert(0 && "unknown global constant");
+  LLVM_UNREACHABLE("unknown global constant");
 }
 
 
diff --git a/lib/CodeGen/GCMetadata.cpp b/lib/CodeGen/GCMetadata.cpp
index 14177da..f711157 100644
--- a/lib/CodeGen/GCMetadata.cpp
+++ b/lib/CodeGen/GCMetadata.cpp
@@ -144,7 +144,7 @@
 
 static const char *DescKind(GC::PointKind Kind) {
   switch (Kind) {
-    default: assert(0 && "Unknown GC point kind");
+    default: LLVM_UNREACHABLE("Unknown GC point kind");
     case GC::Loop:     return "loop";
     case GC::Return:   return "return";
     case GC::PreCall:  return "pre-call";
diff --git a/lib/CodeGen/IntrinsicLowering.cpp b/lib/CodeGen/IntrinsicLowering.cpp
index 9eacdfe..2c28660 100644
--- a/lib/CodeGen/IntrinsicLowering.cpp
+++ b/lib/CodeGen/IntrinsicLowering.cpp
@@ -157,7 +157,7 @@
   IRBuilder<> Builder(IP->getParent(), IP);
 
   switch(BitSize) {
-  default: assert(0 && "Unhandled type size of value to byteswap!");
+  default: LLVM_UNREACHABLE("Unhandled type size of value to byteswap!");
   case 16: {
     Value *Tmp1 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
                                     "bswap.2");
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 6abe465..ed23bef 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -1102,7 +1102,7 @@
   unsigned SrcReg, DstReg, SrcSubReg, DstSubReg;
   if (tii_->isMoveInstr(*VNI->copy, SrcReg, DstReg, SrcSubReg, DstSubReg))
     return SrcReg;
-  assert(0 && "Unrecognized copy instruction!");
+  LLVM_UNREACHABLE("Unrecognized copy instruction!");
   return 0;
 }
 
diff --git a/lib/CodeGen/MachOCodeEmitter.cpp b/lib/CodeGen/MachOCodeEmitter.cpp
index fccbf65..a076a3c 100644
--- a/lib/CodeGen/MachOCodeEmitter.cpp
+++ b/lib/CodeGen/MachOCodeEmitter.cpp
@@ -19,6 +19,7 @@
 #include "llvm/Target/TargetAsmInfo.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetMachine.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Mangler.h"
 #include "llvm/Support/OutputBuffer.h"
 #include <vector>
@@ -104,7 +105,7 @@
       // FIXME: This should be a set or something that uniques
       MOW.PendingGlobals.push_back(MR.getGlobalValue());
     } else {
-      assert(0 && "Unhandled relocation type");
+      LLVM_UNREACHABLE("Unhandled relocation type");
     }
     MOS->addRelocation(MR);
   }
diff --git a/lib/CodeGen/MachOWriter.cpp b/lib/CodeGen/MachOWriter.cpp
index 12f5cec..7542d9e 100644
--- a/lib/CodeGen/MachOWriter.cpp
+++ b/lib/CodeGen/MachOWriter.cpp
@@ -669,7 +669,7 @@
           ptr[6] = val >> 48;
           ptr[7] = val >> 56;
         } else {
-          assert(0 && "Not implemented: bit widths > 64");
+          LLVM_UNREACHABLE("Not implemented: bit widths > 64");
         }
         break;
       }
@@ -733,7 +733,7 @@
                                  PA+SL->getElementOffset(i)));
     } else {
       cerr << "Bad Type: " << *PC->getType() << "\n";
-      assert(0 && "Unknown constant type to initialize memory with!");
+      LLVM_UNREACHABLE("Unknown constant type to initialize memory with!");
     }
   }
 }
@@ -749,7 +749,7 @@
 
   switch (GV->getLinkage()) {
   default:
-    assert(0 && "Unexpected linkage type!");
+    LLVM_UNREACHABLE("Unexpected linkage type!");
     break;
   case GlobalValue::WeakAnyLinkage:
   case GlobalValue::WeakODRLinkage:
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index d44305f..2435855 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -23,6 +23,7 @@
 #include "llvm/Target/TargetInstrDesc.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Analysis/DebugInfo.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/LeakDetector.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/Streams.h"
@@ -156,7 +157,7 @@
     return false;
   
   switch (getType()) {
-  default: assert(0 && "Unrecognized operand type");
+  default: LLVM_UNREACHABLE("Unrecognized operand type");
   case MachineOperand::MO_Register:
     return getReg() == Other.getReg() && isDef() == Other.isDef() &&
            getSubReg() == Other.getSubReg();
@@ -274,7 +275,7 @@
     OS << '>';
     break;
   default:
-    assert(0 && "Unrecognized operand type");
+    LLVM_UNREACHABLE("Unrecognized operand type");
   }
   
   if (unsigned TF = getTargetFlags())
diff --git a/lib/CodeGen/MachineModuleInfo.cpp b/lib/CodeGen/MachineModuleInfo.cpp
index 1d8109e..798492b 100644
--- a/lib/CodeGen/MachineModuleInfo.cpp
+++ b/lib/CodeGen/MachineModuleInfo.cpp
@@ -23,6 +23,7 @@
 #include "llvm/Instructions.h"
 #include "llvm/Module.h"
 #include "llvm/Support/Dwarf.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Streams.h"
 using namespace llvm;
 using namespace llvm::dwarf;
@@ -290,7 +291,7 @@
   }
 
   // This should never happen
-  assert(0 && "Personality function should be set!");
+  LLVM_UNREACHABLE("Personality function should be set!");
   return 0;
 }
 
diff --git a/lib/CodeGen/PostRASchedulerList.cpp b/lib/CodeGen/PostRASchedulerList.cpp
index de77468..77cbf29 100644
--- a/lib/CodeGen/PostRASchedulerList.cpp
+++ b/lib/CodeGen/PostRASchedulerList.cpp
@@ -34,6 +34,7 @@
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/ADT/Statistic.h"
 #include <map>
 using namespace llvm;
@@ -793,7 +794,7 @@
     cerr << "*** Scheduling failed! ***\n";
     SuccSU->dump(this);
     cerr << " has been released too many times!\n";
-    assert(0);
+    llvm_unreachable();
   }
 #endif
   
diff --git a/lib/CodeGen/PseudoSourceValue.cpp b/lib/CodeGen/PseudoSourceValue.cpp
index b4c20e6..55a6cf5 100644
--- a/lib/CodeGen/PseudoSourceValue.cpp
+++ b/lib/CodeGen/PseudoSourceValue.cpp
@@ -15,6 +15,7 @@
 #include "llvm/CodeGen/PseudoSourceValue.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/raw_ostream.h"
 #include <map>
@@ -83,7 +84,7 @@
       this == getConstantPool() ||
       this == getJumpTable())
     return true;
-  assert(0 && "Unknown PseudoSourceValue!");
+  LLVM_UNREACHABLE("Unknown PseudoSourceValue!");
   return false;
 }
 
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index eb9dccb..7f233b2 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -393,7 +393,7 @@
 
   assert(Depth <= 6 && "GetNegatedExpression doesn't match isNegatibleForFree");
   switch (Op.getOpcode()) {
-  default: assert(0 && "Unknown code");
+  default: LLVM_UNREACHABLE("Unknown code");
   case ISD::ConstantFP: {
     APFloat V = cast<ConstantFPSDNode>(Op)->getValueAPF();
     V.changeSign();
@@ -5063,7 +5063,7 @@
     if (Value.getOpcode() != ISD::TargetConstantFP) {
       SDValue Tmp;
       switch (CFP->getValueType(0).getSimpleVT()) {
-      default: assert(0 && "Unknown FP type");
+      default: LLVM_UNREACHABLE("Unknown FP type");
       case MVT::f80:    // We don't do this for these yet.
       case MVT::f128:
       case MVT::ppcf128:
@@ -6107,7 +6107,7 @@
     SrcValue = ST->getSrcValue();
     SrcValueOffset = ST->getSrcValueOffset();
   } else {
-    assert(0 && "FindAliasInfo expected a memory operand");
+    LLVM_UNREACHABLE("FindAliasInfo expected a memory operand");
   }
 
   return false;
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index a4fff89..5cd3182 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -983,7 +983,7 @@
     return Tmp2;
   case ISD::BUILD_VECTOR:
     switch (TLI.getOperationAction(ISD::BUILD_VECTOR, Node->getValueType(0))) {
-    default: assert(0 && "This action is not supported yet!");
+    default: LLVM_UNREACHABLE("This action is not supported yet!");
     case TargetLowering::Custom:
       Tmp3 = TLI.LowerOperation(Result, DAG);
       if (Tmp3.getNode()) {
@@ -1100,7 +1100,7 @@
       Tmp4 = Result.getValue(1);
 
       switch (TLI.getOperationAction(Node->getOpcode(), VT)) {
-      default: assert(0 && "This action is not supported yet!");
+      default: LLVM_UNREACHABLE("This action is not supported yet!");
       case TargetLowering::Legal:
         // If this is an unaligned load and the target doesn't support it,
         // expand it.
@@ -1270,7 +1270,7 @@
         Tmp2 = LegalizeOp(Ch);
       } else {
         switch (TLI.getLoadExtAction(ExtType, SrcVT)) {
-        default: assert(0 && "This action is not supported yet!");
+        default: LLVM_UNREACHABLE("This action is not supported yet!");
         case TargetLowering::Custom:
           isCustom = true;
           // FALLTHROUGH
@@ -1363,7 +1363,7 @@
 
         MVT VT = Tmp3.getValueType();
         switch (TLI.getOperationAction(ISD::STORE, VT)) {
-        default: assert(0 && "This action is not supported yet!");
+        default: LLVM_UNREACHABLE("This action is not supported yet!");
         case TargetLowering::Legal:
           // If this is an unaligned store and the target doesn't support it,
           // expand it.
@@ -1463,7 +1463,7 @@
                                           ST->getOffset());
 
         switch (TLI.getTruncStoreAction(ST->getValue().getValueType(), StVT)) {
-        default: assert(0 && "This action is not supported yet!");
+        default: LLVM_UNREACHABLE("This action is not supported yet!");
         case TargetLowering::Legal:
           // If this is an unaligned store and the target doesn't support it,
           // expand it.
@@ -1691,7 +1691,7 @@
   MVT OpVT = LHS.getValueType();
   ISD::CondCode CCCode = cast<CondCodeSDNode>(CC)->get();
   switch (TLI.getCondCodeAction(CCCode, OpVT)) {
-  default: assert(0 && "Unknown condition code action!");
+  default: LLVM_UNREACHABLE("Unknown condition code action!");
   case TargetLowering::Legal:
     // Nothing to do.
     break;
@@ -1926,7 +1926,7 @@
                                               RTLIB::Libcall Call_PPCF128) {
   RTLIB::Libcall LC;
   switch (Node->getValueType(0).getSimpleVT()) {
-  default: assert(0 && "Unexpected request for libcall!");
+  default: LLVM_UNREACHABLE("Unexpected request for libcall!");
   case MVT::f32: LC = Call_F32; break;
   case MVT::f64: LC = Call_F64; break;
   case MVT::f80: LC = Call_F80; break;
@@ -1942,7 +1942,7 @@
                                                RTLIB::Libcall Call_I128) {
   RTLIB::Libcall LC;
   switch (Node->getValueType(0).getSimpleVT()) {
-  default: assert(0 && "Unexpected request for libcall!");
+  default: LLVM_UNREACHABLE("Unexpected request for libcall!");
   case MVT::i16: LC = Call_I16; break;
   case MVT::i32: LC = Call_I32; break;
   case MVT::i64: LC = Call_I64; break;
@@ -2028,7 +2028,7 @@
   // offset depending on the data type.
   uint64_t FF;
   switch (Op0.getValueType().getSimpleVT()) {
-  default: assert(0 && "Unsupported integer type!");
+  default: LLVM_UNREACHABLE("Unsupported integer type!");
   case MVT::i8 : FF = 0x43800000ULL; break;  // 2^8  (as a float)
   case MVT::i16: FF = 0x47800000ULL; break;  // 2^16 (as a float)
   case MVT::i32: FF = 0x4F800000ULL; break;  // 2^32 (as a float)
@@ -2192,7 +2192,7 @@
 SDValue SelectionDAGLegalize::ExpandBitCount(unsigned Opc, SDValue Op,
                                              DebugLoc dl) {
   switch (Opc) {
-  default: assert(0 && "Cannot expand this yet!");
+  default: LLVM_UNREACHABLE("Cannot expand this yet!");
   case ISD::CTPOP: {
     static const uint64_t mask[6] = {
       0x5555555555555555ULL, 0x3333333333333333ULL,
@@ -2306,7 +2306,7 @@
     else if (VT.isFloatingPoint())
       Results.push_back(DAG.getConstantFP(0, VT));
     else
-      assert(0 && "Unknown value type!");
+      LLVM_UNREACHABLE("Unknown value type!");
     break;
   }
   case ISD::TRAP: {
@@ -2810,7 +2810,7 @@
       // type in some cases cases.
       // Also, we can fall back to a division in some cases, but that's a big
       // performance hit in the general case.
-      assert(0 && "Don't know how to expand this operation yet!");
+      LLVM_UNREACHABLE("Don't know how to expand this operation yet!");
     }
     if (isSigned) {
       Tmp1 = DAG.getConstant(VT.getSizeInBits() - 1, TLI.getShiftAmountTy());
@@ -3091,7 +3091,7 @@
         break;
     }
     if (NewInTy.isInteger())
-      assert(0 && "Cannot promote Legal Integer SETCC yet");
+      LLVM_UNREACHABLE("Cannot promote Legal Integer SETCC yet");
     else {
       Tmp1 = DAG.getNode(ISD::FP_EXTEND, dl, NewInTy, Tmp1);
       Tmp2 = DAG.getNode(ISD::FP_EXTEND, dl, NewInTy, Tmp2);
diff --git a/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index 730619c..63ddbed 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -491,7 +491,7 @@
   SDValue Res;
 
   switch (getTypeAction(N->getOperand(0).getValueType())) {
-  default: assert(0 && "Unknown type action!");
+  default: LLVM_UNREACHABLE("Unknown type action!");
   case Legal:
   case ExpandInteger:
     Res = N->getOperand(0);
@@ -666,7 +666,7 @@
   // insert sign extends for ALL conditions, but zero extend is cheaper on
   // many machines (an AND instead of two shifts), so prefer it.
   switch (CCCode) {
-  default: assert(0 && "Unknown integer comparison!");
+  default: LLVM_UNREACHABLE("Unknown integer comparison!");
   case ISD::SETEQ:
   case ISD::SETNE:
   case ISD::SETUGE:
@@ -1104,7 +1104,7 @@
                       DAG.getConstant(~HighBitMask, ShTy));
 
     switch (N->getOpcode()) {
-    default: assert(0 && "Unknown shift");
+    default: LLVM_UNREACHABLE("Unknown shift");
     case ISD::SHL:
       Lo = DAG.getConstant(0, NVT);              // Low part is zero.
       Hi = DAG.getNode(ISD::SHL, dl, NVT, InL, Amt); // High part from Lo part.
@@ -1132,7 +1132,7 @@
                                  Amt);
     unsigned Op1, Op2;
     switch (N->getOpcode()) {
-    default: assert(0 && "Unknown shift");
+    default: LLVM_UNREACHABLE("Unknown shift");
     case ISD::SHL:  Op1 = ISD::SHL; Op2 = ISD::SRL; break;
     case ISD::SRL:
     case ISD::SRA:  Op1 = ISD::SRL; Op2 = ISD::SHL; break;
@@ -1172,7 +1172,7 @@
 
   SDValue Lo1, Hi1, Lo2, Hi2;
   switch (N->getOpcode()) {
-  default: assert(0 && "Unknown shift");
+  default: LLVM_UNREACHABLE("Unknown shift");
   case ISD::SHL:
     // ShAmt < NVTBits
     Lo1 = DAG.getConstant(0, NVT);                  // Low part is zero.
@@ -1792,7 +1792,7 @@
   }
 
   if (!ExpandShiftWithUnknownAmountBit(N, Lo, Hi))
-    assert(0 && "Unsupported shift!");
+    LLVM_UNREACHABLE("Unsupported shift!");
 }
 
 void DAGTypeLegalizer::ExpandIntRes_SIGN_EXTEND(SDNode *N,
@@ -2050,7 +2050,7 @@
   // FIXME: This generated code sucks.
   ISD::CondCode LowCC;
   switch (CCCode) {
-  default: assert(0 && "Unknown integer setcc!");
+  default: LLVM_UNREACHABLE("Unknown integer setcc!");
   case ISD::SETLT:
   case ISD::SETULT: LowCC = ISD::SETULT; break;
   case ISD::SETGT:
diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index d4e886d..013b18b 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -278,7 +278,7 @@
       cerr << "ScalarizeVectorOperand Op #" << OpNo << ": ";
       N->dump(&DAG); cerr << "\n";
 #endif
-      assert(0 && "Do not know how to scalarize this operator's operand!");
+      LLVM_UNREACHABLE("Do not know how to scalarize this operator's operand!");
     case ISD::BIT_CONVERT:
       Res = ScalarizeVecOp_BIT_CONVERT(N);
       break;
@@ -576,7 +576,7 @@
   SDValue VLo, VHi;
   MVT InVT = N->getOperand(0).getValueType();
   switch (getTypeAction(InVT)) {
-  default: assert(0 && "Unexpected type action!");
+  default: LLVM_UNREACHABLE("Unexpected type action!");
   case Legal: {
     MVT InNVT = MVT::getVectorVT(InVT.getVectorElementType(),
                                  LoVT.getVectorNumElements());
@@ -768,7 +768,7 @@
   // Split the input.
   MVT InVT = N->getOperand(0).getValueType();
   switch (getTypeAction(InVT)) {
-  default: assert(0 && "Unexpected type action!");
+  default: LLVM_UNREACHABLE("Unexpected type action!");
   case Legal: {
     MVT InNVT = MVT::getVectorVT(InVT.getVectorElementType(),
                                  LoVT.getVectorNumElements());
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
index 4f6e59c..52626db 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGFast.cpp
@@ -140,7 +140,7 @@
     cerr << "*** Scheduling failed! ***\n";
     PredSU->dump(this);
     cerr << " has been released too many times!\n";
-    assert(0);
+    llvm_unreachable();
   }
 #endif
   
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp
index c432534..afce348 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGList.cpp
@@ -29,6 +29,7 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/ADT/PriorityQueue.h"
 #include "llvm/ADT/Statistic.h"
 #include <climits>
@@ -113,7 +114,7 @@
     cerr << "*** Scheduling failed! ***\n";
     SuccSU->dump(this);
     cerr << " has been released too many times!\n";
-    assert(0);
+    llvm_unreachable();
   }
 #endif
   
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
index c97e2a8..85794b9 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
@@ -25,6 +25,7 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/ADT/PriorityQueue.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/Statistic.h"
@@ -202,7 +203,7 @@
     cerr << "*** Scheduling failed! ***\n";
     PredSU->dump(this);
     cerr << " has been released too many times!\n";
-    assert(0);
+    llvm_unreachable();
   }
 #endif
   
@@ -829,7 +830,7 @@
     cerr << "*** Scheduling failed! ***\n";
     SuccSU->dump(this);
     cerr << " has been released too many times!\n";
-    assert(0);
+    llvm_unreachable();
   }
 #endif
   
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodesEmit.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodesEmit.cpp
index f9bfe00..80a8ae9 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodesEmit.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodesEmit.cpp
@@ -25,6 +25,7 @@
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 using namespace llvm;
 
@@ -430,7 +431,7 @@
     MI->addOperand(MachineOperand::CreateImm(SubIdx));
     BB->insert(InsertPos, MI);
   } else
-    assert(0 && "Node is not insert_subreg, extract_subreg, or subreg_to_reg");
+    LLVM_UNREACHABLE("Node is not insert_subreg, extract_subreg, or subreg_to_reg");
      
   SDValue Op(Node, 0);
   bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second;
@@ -551,10 +552,10 @@
 #ifndef NDEBUG
     Node->dump(DAG);
 #endif
-    assert(0 && "This target-independent node should have been selected!");
+    LLVM_UNREACHABLE("This target-independent node should have been selected!");
     break;
   case ISD::EntryToken:
-    assert(0 && "EntryToken should have been excluded from the schedule!");
+    LLVM_UNREACHABLE("EntryToken should have been excluded from the schedule!");
     break;
   case ISD::TokenFactor: // fall thru
     break;
@@ -618,7 +619,7 @@
       ++i;  // Skip the ID value.
         
       switch (Flags & 7) {
-      default: assert(0 && "Bad flags!");
+      default: LLVM_UNREACHABLE("Bad flags!");
       case 2:   // Def of register.
         for (; NumVals; --NumVals, ++i) {
           unsigned Reg = cast<RegisterSDNode>(Node->getOperand(i))->getReg();
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 29f0cb2..98841f8 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -31,6 +31,7 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"
@@ -53,7 +54,7 @@
 
 static const fltSemantics *MVTToAPFloatSemantics(MVT VT) {
   switch (VT.getSimpleVT()) {
-  default: assert(0 && "Unknown FP format");
+  default: LLVM_UNREACHABLE("Unknown FP format");
   case MVT::f32:     return &APFloat::IEEEsingle;
   case MVT::f64:     return &APFloat::IEEEdouble;
   case MVT::f80:     return &APFloat::x87DoubleExtended;
@@ -243,7 +244,7 @@
 /// if the operation does not depend on the sign of the input (setne and seteq).
 static int isSignedOp(ISD::CondCode Opcode) {
   switch (Opcode) {
-  default: assert(0 && "Illegal integer setcc operation!");
+  default: LLVM_UNREACHABLE("Illegal integer setcc operation!");
   case ISD::SETEQ:
   case ISD::SETNE: return 0;
   case ISD::SETLT:
@@ -363,7 +364,7 @@
   switch (N->getOpcode()) {
   case ISD::TargetExternalSymbol:
   case ISD::ExternalSymbol:
-    assert(0 && "Should only be used on nodes with operands");
+    LLVM_UNREACHABLE("Should only be used on nodes with operands");
   default: break;  // Normal nodes don't need extra info.
   case ISD::ARG_FLAGS:
     ID.AddInteger(cast<ARG_FLAGSSDNode>(N)->getArgFlags().getRawBits());
@@ -626,7 +627,7 @@
   bool Erased = false;
   switch (N->getOpcode()) {
   case ISD::EntryToken:
-    assert(0 && "EntryToken should not be in CSEMaps!");
+    LLVM_UNREACHABLE("EntryToken should not be in CSEMaps!");
     return false;
   case ISD::HANDLENODE: return false;  // noop.
   case ISD::CONDCODE:
@@ -668,7 +669,7 @@
       !N->isMachineOpcode() && !doNotCSE(N)) {
     N->dump(this);
     cerr << "\n";
-    assert(0 && "Node is not in map!");
+    LLVM_UNREACHABLE("Node is not in map!");
   }
 #endif
   return Erased;
@@ -1442,7 +1443,7 @@
       const APInt &C1 = N1C->getAPIntValue();
 
       switch (Cond) {
-      default: assert(0 && "Unknown integer setcc!");
+      default: LLVM_UNREACHABLE("Unknown integer setcc!");
       case ISD::SETEQ:  return getConstant(C1 == C2, VT);
       case ISD::SETNE:  return getConstant(C1 != C2, VT);
       case ISD::SETULT: return getConstant(C1.ult(C2), VT);
@@ -2371,7 +2372,7 @@
   case ISD::MERGE_VALUES:
   case ISD::CONCAT_VECTORS:
     return Operand;         // Factor, merge or concat of one node?  No need.
-  case ISD::FP_ROUND: assert(0 && "Invalid method to make FP_ROUND node");
+  case ISD::FP_ROUND: LLVM_UNREACHABLE("Invalid method to make FP_ROUND node");
   case ISD::FP_EXTEND:
     assert(VT.isFloatingPoint() &&
            Operand.getValueType().isFloatingPoint() && "Invalid FP cast!");
@@ -2946,7 +2947,7 @@
     }
     break;
   case ISD::VECTOR_SHUFFLE:
-    assert(0 && "should use getVectorShuffle constructor!");
+    LLVM_UNREACHABLE("should use getVectorShuffle constructor!");
     break;
   case ISD::BIT_CONVERT:
     // Fold bit_convert nodes from a type to themselves.
@@ -4060,7 +4061,7 @@
 
 SDVTList SelectionDAG::getVTList(const MVT *VTs, unsigned NumVTs) {
   switch (NumVTs) {
-    case 0: assert(0 && "Cannot have nodes without results!");
+    case 0: LLVM_UNREACHABLE("Cannot have nodes without results!");
     case 1: return getVTList(VTs[0]);
     case 2: return getVTList(VTs[0], VTs[1]);
     case 3: return getVTList(VTs[0], VTs[1], VTs[2]);
@@ -5341,7 +5342,7 @@
 
   case ISD::CONVERT_RNDSAT: {
     switch (cast<CvtRndSatSDNode>(this)->getCvtCode()) {
-    default: assert(0 && "Unknown cvt code!");
+    default: LLVM_UNREACHABLE("Unknown cvt code!");
     case ISD::CVT_FF:  return "cvt_ff";
     case ISD::CVT_FS:  return "cvt_fs";
     case ISD::CVT_FU:  return "cvt_fu";
@@ -5393,7 +5394,7 @@
 
   case ISD::CONDCODE:
     switch (cast<CondCodeSDNode>(this)->get()) {
-    default: assert(0 && "Unknown setcc condition!");
+    default: LLVM_UNREACHABLE("Unknown setcc condition!");
     case ISD::SETOEQ:  return "setoeq";
     case ISD::SETOGT:  return "setogt";
     case ISD::SETOGE:  return "setoge";
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
index 1e31b8f..3882abd 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
@@ -556,7 +556,7 @@
   if (PartVT.getSizeInBits() == ValueVT.getSizeInBits())
     return DAG.getNode(ISD::BIT_CONVERT, dl, ValueVT, Val);
 
-  assert(0 && "Unknown mismatch!");
+  LLVM_UNREACHABLE("Unknown mismatch!");
   return SDValue();
 }
 
@@ -592,7 +592,7 @@
         ValueVT = MVT::getIntegerVT(NumParts * PartBits);
         Val = DAG.getNode(ExtendKind, dl, ValueVT, Val);
       } else {
-        assert(0 && "Unknown mismatch!");
+        LLVM_UNREACHABLE("Unknown mismatch!");
       }
     } else if (PartBits == ValueVT.getSizeInBits()) {
       // Different types of the same size.
@@ -604,7 +604,7 @@
         ValueVT = MVT::getIntegerVT(NumParts * PartBits);
         Val = DAG.getNode(ISD::TRUNCATE, dl, ValueVT, Val);
       } else {
-        assert(0 && "Unknown mismatch!");
+        LLVM_UNREACHABLE("Unknown mismatch!");
       }
     }
 
@@ -1073,7 +1073,7 @@
   case FCmpInst::FCMP_UNE:   FOC = ISD::SETNE; FPC = ISD::SETUNE; break;
   case FCmpInst::FCMP_TRUE:  FOC = FPC = ISD::SETTRUE; break;
   default:
-    assert(0 && "Invalid FCmp predicate opcode!");
+    LLVM_UNREACHABLE("Invalid FCmp predicate opcode!");
     FOC = FPC = ISD::SETFALSE;
     break;
   }
@@ -1099,7 +1099,7 @@
   case ICmpInst::ICMP_SGT: return ISD::SETGT;
   case ICmpInst::ICMP_UGT: return ISD::SETUGT;
   default:
-    assert(0 && "Invalid ICmp predicate opcode!");
+    LLVM_UNREACHABLE("Invalid ICmp predicate opcode!");
     return ISD::SETNE;
   }
 }
@@ -1131,7 +1131,7 @@
         Condition = getFCmpCondCode(FC->getPredicate());
       } else {
         Condition = ISD::SETEQ; // silence warning.
-        assert(0 && "Unknown compare instruction");
+        LLVM_UNREACHABLE("Unknown compare instruction");
       }
 
       CaseBlock CB(Condition, BOp->getOperand(0),
@@ -4263,7 +4263,7 @@
 
   case Intrinsic::gcread:
   case Intrinsic::gcwrite:
-    assert(0 && "GC failed to lower gcread/gcwrite intrinsics!");
+    LLVM_UNREACHABLE("GC failed to lower gcread/gcwrite intrinsics!");
     return 0;
 
   case Intrinsic::flt_rounds: {
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
index b5c3d4d..6039ef5 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
@@ -23,6 +23,7 @@
 #include "llvm/CodeGen/SelectionDAGNodes.h"
 #include "llvm/CodeGen/ValueTypes.h"
 #include "llvm/Support/CallSite.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetMachine.h"
 #include <vector>
 #include <set>
@@ -535,12 +536,10 @@
   void visitVACopy(CallInst &I);
 
   void visitUserOp1(Instruction &I) {
-    assert(0 && "UserOp1 should not exist at instruction selection time!");
-    abort();
+    LLVM_UNREACHABLE("UserOp1 should not exist at instruction selection time!");
   }
   void visitUserOp2(Instruction &I) {
-    assert(0 && "UserOp2 should not exist at instruction selection time!");
-    abort();
+    LLVM_UNREACHABLE("UserOp2 should not exist at instruction selection time!");
   }
   
   const char *implVisitBinaryAtomic(CallInst& I, ISD::NodeType Op);
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index cadf854..b084ab7 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -832,7 +832,7 @@
               BI->dump();
             }
             if (EnableFastISelAbort)
-              assert(0 && "FastISel didn't handle a PHI in a successor");
+              LLVM_UNREACHABLE("FastISel didn't handle a PHI in a successor");
             break;
           }
 
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index b9b518a..cddb516 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -23,6 +23,7 @@
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 using namespace llvm;
 
@@ -1840,7 +1841,7 @@
     if (CFP->getValueAPF().isNaN()) {
       // If an operand is known to be a nan, we can fold it.
       switch (ISD::getUnorderedFlavor(Cond)) {
-      default: assert(0 && "Unknown flavor!");
+      default: LLVM_UNREACHABLE("Unknown flavor!");
       case 0:  // Known false.
         return DAG.getConstant(0, VT);
       case 1:  // Known true.
@@ -2000,7 +2001,7 @@
   SDValue Temp;
   if (N0.getValueType() == MVT::i1 && foldBooleans) {
     switch (Cond) {
-    default: assert(0 && "Unknown integer setcc!");
+    default: LLVM_UNREACHABLE("Unknown integer setcc!");
     case ISD::SETEQ:  // X == Y  -> ~(X^Y)
       Temp = DAG.getNode(ISD::XOR, dl, MVT::i1, N0, N1);
       N0 = DAG.getNOT(dl, Temp, MVT::i1);
@@ -2310,7 +2311,7 @@
 /// is.
 static unsigned getConstraintGenerality(TargetLowering::ConstraintType CT) {
   switch (CT) {
-  default: assert(0 && "Unknown constraint type!");
+  default: LLVM_UNREACHABLE("Unknown constraint type!");
   case TargetLowering::C_Other:
   case TargetLowering::C_Unknown:
     return 0;
diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index d1523f8..7dcd4cc 100644
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -28,6 +28,7 @@
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/STLExtras.h"
@@ -1333,8 +1334,7 @@
     DstSubIdx = CopyMI->getOperand(3).getImm();
     SrcReg    = CopyMI->getOperand(2).getReg();
   } else if (!tii_->isMoveInstr(*CopyMI, SrcReg, DstReg, SrcSubIdx, DstSubIdx)){
-    assert(0 && "Unrecognized copy instruction!");
-    return false;
+    LLVM_UNREACHABLE("Unrecognized copy instruction!");
   }
 
   // If they are already joined we continue.
@@ -2051,7 +2051,7 @@
         *tri_->getSuperRegisters(LHS.reg))
       // Imprecise sub-register information. Can't handle it.
       return false;
-    assert(0 && "No copies from the RHS?");
+    LLVM_UNREACHABLE("No copies from the RHS?");
   } else {
     LHSValNo = EliminatedLHSVals[0];
   }
diff --git a/lib/CodeGen/VirtRegRewriter.cpp b/lib/CodeGen/VirtRegRewriter.cpp
index 48558fe..7a8b39a 100644
--- a/lib/CodeGen/VirtRegRewriter.cpp
+++ b/lib/CodeGen/VirtRegRewriter.cpp
@@ -10,6 +10,7 @@
 #define DEBUG_TYPE "virtregrewriter"
 #include "VirtRegRewriter.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/STLExtras.h"
@@ -999,7 +1000,7 @@
     // Unfold current MI.
     SmallVector<MachineInstr*, 4> NewMIs;
     if (!TII->unfoldMemoryOperand(MF, &MI, VirtReg, false, false, NewMIs))
-      assert(0 && "Unable unfold the load / store folding instruction!");
+      LLVM_UNREACHABLE("Unable unfold the load / store folding instruction!");
     assert(NewMIs.size() == 1);
     AssignPhysToVirtReg(NewMIs[0], VirtReg, PhysReg);
     VRM.transferRestorePts(&MI, NewMIs[0]);
@@ -1015,7 +1016,7 @@
       NextMII = next(NextMII);
       NewMIs.clear();
       if (!TII->unfoldMemoryOperand(MF, &NextMI, VirtReg, false, false, NewMIs))
-        assert(0 && "Unable unfold the load / store folding instruction!");
+        LLVM_UNREACHABLE("Unable unfold the load / store folding instruction!");
       assert(NewMIs.size() == 1);
       AssignPhysToVirtReg(NewMIs[0], VirtReg, PhysReg);
       VRM.transferRestorePts(&NextMI, NewMIs[0]);
@@ -1451,7 +1452,7 @@
           assert(RC && "Unable to determine register class!");
           int SS = VRM.getEmergencySpillSlot(RC);
           if (UsedSS.count(SS))
-            assert(0 && "Need to spill more than one physical registers!");
+            LLVM_UNREACHABLE("Need to spill more than one physical registers!");
           UsedSS.insert(SS);
           TII->storeRegToStackSlot(MBB, MII, PhysReg, true, SS, RC);
           MachineInstr *StoreMI = prior(MII);
@@ -2176,7 +2177,7 @@
 
 llvm::VirtRegRewriter* llvm::createVirtRegRewriter() {
   switch (RewriterOpt) {
-  default: assert(0 && "Unreachable!");
+  default: LLVM_UNREACHABLE("Unreachable!");
   case local:
     return new LocalRewriter();
   case trivial:
diff --git a/lib/ExecutionEngine/ExecutionEngine.cpp b/lib/ExecutionEngine/ExecutionEngine.cpp
index 7c74565..226cd4f 100644
--- a/lib/ExecutionEngine/ExecutionEngine.cpp
+++ b/lib/ExecutionEngine/ExecutionEngine.cpp
@@ -421,7 +421,7 @@
           const_cast<GlobalVariable *>(dyn_cast<GlobalVariable>(GV)))
     EmitGlobalVariable(GVar);
   else
-    assert(0 && "Global hasn't had an address allocated yet!");
+    LLVM_UNREACHABLE("Global hasn't had an address allocated yet!");
   return state.getGlobalAddressMap(locked)[GV];
 }
 
@@ -548,7 +548,7 @@
       GenericValue GV = getConstantValue(Op0);
       const Type* DestTy = CE->getType();
       switch (Op0->getType()->getTypeID()) {
-        default: assert(0 && "Invalid bitcast operand");
+        default: LLVM_UNREACHABLE("Invalid bitcast operand");
         case Type::IntegerTyID:
           assert(DestTy->isFloatingPoint() && "invalid bitcast");
           if (DestTy == Type::FloatTy)
@@ -590,7 +590,7 @@
       default: LLVM_UNREACHABLE("Bad add type!");
       case Type::IntegerTyID:
         switch (CE->getOpcode()) {
-          default: assert(0 && "Invalid integer opcode");
+          default: LLVM_UNREACHABLE("Invalid integer opcode");
           case Instruction::Add: GV.IntVal = LHS.IntVal + RHS.IntVal; break;
           case Instruction::Sub: GV.IntVal = LHS.IntVal - RHS.IntVal; break;
           case Instruction::Mul: GV.IntVal = LHS.IntVal * RHS.IntVal; break;
@@ -638,7 +638,7 @@
       case Type::FP128TyID: {
         APFloat apfLHS = APFloat(LHS.IntVal);
         switch (CE->getOpcode()) {
-          default: assert(0 && "Invalid long double opcode");llvm_unreachable();
+          default: LLVM_UNREACHABLE("Invalid long double opcode");llvm_unreachable();
           case Instruction::FAdd:
             apfLHS.add(APFloat(RHS.IntVal), APFloat::rmNearestTiesToEven);
             GV.IntVal = apfLHS.bitcastToAPInt();
@@ -698,7 +698,7 @@
     else if (const GlobalVariable* GV = dyn_cast<GlobalVariable>(C))
       Result = PTOGV(getOrEmitGlobalVariable(const_cast<GlobalVariable*>(GV)));
     else
-      assert(0 && "Unknown constant pointer type!");
+      LLVM_UNREACHABLE("Unknown constant pointer type!");
     break;
   default:
     std::string msg;
@@ -881,7 +881,7 @@
   }
 
   cerr << "Bad Type: " << *Init->getType() << "\n";
-  assert(0 && "Unknown constant type to initialize memory with!");
+  LLVM_UNREACHABLE("Unknown constant type to initialize memory with!");
 }
 
 /// EmitGlobals - Emit all of the global variables to memory, storing their
diff --git a/lib/ExecutionEngine/ExecutionEngineBindings.cpp b/lib/ExecutionEngine/ExecutionEngineBindings.cpp
index 401a226..43389e0 100644
--- a/lib/ExecutionEngine/ExecutionEngineBindings.cpp
+++ b/lib/ExecutionEngine/ExecutionEngineBindings.cpp
@@ -15,6 +15,7 @@
 #include "llvm-c/ExecutionEngine.h"
 #include "llvm/ExecutionEngine/GenericValue.h"
 #include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <cstring>
 
 using namespace llvm;
@@ -45,8 +46,7 @@
     GenVal->DoubleVal = N;
     break;
   default:
-    assert(0 && "LLVMGenericValueToFloat supports only float and double.");
-    break;
+    LLVM_UNREACHABLE("LLVMGenericValueToFloat supports only float and double.");
   }
   return wrap(GenVal);
 }
@@ -75,7 +75,7 @@
   case Type::DoubleTyID:
     return unwrap(GenVal)->DoubleVal;
   default:
-    assert(0 && "LLVMGenericValueToFloat supports only float and double.");
+    LLVM_UNREACHABLE("LLVMGenericValueToFloat supports only float and double.");
     break;
   }
   return 0; // Not reached
diff --git a/lib/ExecutionEngine/Interpreter/Execution.cpp b/lib/ExecutionEngine/Interpreter/Execution.cpp
index 872bfeb..4a6cafe 100644
--- a/lib/ExecutionEngine/Interpreter/Execution.cpp
+++ b/lib/ExecutionEngine/Interpreter/Execution.cpp
@@ -1079,7 +1079,7 @@
     } else if (SrcTy->isInteger()) {
       Dest.IntVal = Src.IntVal;
     } else 
-      assert(0 && "Invalid BitCast");
+      LLVM_UNREACHABLE("Invalid BitCast");
   } else if (DstTy == Type::FloatTy) {
     if (SrcTy->isInteger())
       Dest.FloatVal = Src.IntVal.bitsToFloat();
@@ -1091,7 +1091,7 @@
     else
       Dest.DoubleVal = Src.DoubleVal;
   } else
-    assert(0 && "Invalid Bitcast");
+    LLVM_UNREACHABLE("Invalid Bitcast");
 
   return Dest;
 }
@@ -1345,7 +1345,7 @@
       DOUT << "  --> ";
       const GenericValue &Val = SF.Values[&I];
       switch (I.getType()->getTypeID()) {
-      default: assert(0 && "Invalid GenericValue Type");
+      default: LLVM_UNREACHABLE("Invalid GenericValue Type");
       case Type::VoidTyID:    DOUT << "void"; break;
       case Type::FloatTyID:   DOUT << "float " << Val.FloatVal; break;
       case Type::DoubleTyID:  DOUT << "double " << Val.DoubleVal; break;
diff --git a/lib/ExecutionEngine/Interpreter/Interpreter.h b/lib/ExecutionEngine/Interpreter/Interpreter.h
index d56161f..f9d4770 100644
--- a/lib/ExecutionEngine/Interpreter/Interpreter.h
+++ b/lib/ExecutionEngine/Interpreter/Interpreter.h
@@ -21,6 +21,7 @@
 #include "llvm/Support/CallSite.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/ErrorHandling.h"
 
 namespace llvm {
 
@@ -145,7 +146,9 @@
   void visitLoadInst(LoadInst &I);
   void visitStoreInst(StoreInst &I);
   void visitGetElementPtrInst(GetElementPtrInst &I);
-  void visitPHINode(PHINode &PN) { assert(0 && "PHI nodes already handled!"); }
+  void visitPHINode(PHINode &PN) { 
+    LLVM_UNREACHABLE("PHI nodes already handled!"); 
+  }
   void visitTruncInst(TruncInst &I);
   void visitZExtInst(ZExtInst &I);
   void visitSExtInst(SExtInst &I);
@@ -174,7 +177,7 @@
   void visitVAArgInst(VAArgInst &I);
   void visitInstruction(Instruction &I) {
     cerr << I;
-    assert(0 && "Instruction not interpretable yet!");
+    LLVM_UNREACHABLE("Instruction not interpretable yet!");
   }
 
   GenericValue callExternalFunction(Function *F,
diff --git a/lib/ExecutionEngine/JIT/JIT.cpp b/lib/ExecutionEngine/JIT/JIT.cpp
index f8f3f20..3edea73 100644
--- a/lib/ExecutionEngine/JIT/JIT.cpp
+++ b/lib/ExecutionEngine/JIT/JIT.cpp
@@ -410,7 +410,7 @@
   if (ArgValues.empty()) {
     GenericValue rv;
     switch (RetTy->getTypeID()) {
-    default: assert(0 && "Unknown return type for function call!");
+    default: LLVM_UNREACHABLE("Unknown return type for function call!");
     case Type::IntegerTyID: {
       unsigned BitWidth = cast<IntegerType>(RetTy)->getBitWidth();
       if (BitWidth == 1)
@@ -424,7 +424,7 @@
       else if (BitWidth <= 64)
         rv.IntVal = APInt(BitWidth, ((int64_t(*)())(intptr_t)FPtr)());
       else 
-        assert(0 && "Integer types > 64 bits not supported");
+        LLVM_UNREACHABLE("Integer types > 64 bits not supported");
       return rv;
     }
     case Type::VoidTyID:
@@ -439,7 +439,7 @@
     case Type::X86_FP80TyID:
     case Type::FP128TyID:
     case Type::PPC_FP128TyID:
-      assert(0 && "long double not supported yet");
+      LLVM_UNREACHABLE("long double not supported yet");
       return rv;
     case Type::PointerTyID:
       return PTOGV(((void*(*)())(intptr_t)FPtr)());
@@ -467,7 +467,7 @@
     const Type *ArgTy = FTy->getParamType(i);
     const GenericValue &AV = ArgValues[i];
     switch (ArgTy->getTypeID()) {
-    default: assert(0 && "Unknown argument type for function call!");
+    default: LLVM_UNREACHABLE("Unknown argument type for function call!");
     case Type::IntegerTyID:
         C = ConstantInt::get(AV.IntVal);
         break;
diff --git a/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp b/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp
index e101ef3..86218f7 100644
--- a/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp
+++ b/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp
@@ -21,6 +21,7 @@
 #include "llvm/CodeGen/MachineLocation.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/ExecutionEngine/JITMemoryManager.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetAsmInfo.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetInstrInfo.h"
@@ -110,7 +111,7 @@
         
         JCE->emitULEB128Bytes(Offset);
       } else {
-        assert(0 && "Machine move no supported yet.");
+        LLVM_UNREACHABLE("Machine move no supported yet.");
       }
     } else if (Src.isReg() &&
       Src.getReg() == MachineLocation::VirtualFP) {
@@ -118,7 +119,7 @@
         JCE->emitByte(dwarf::DW_CFA_def_cfa_register);
         JCE->emitULEB128Bytes(RI->getDwarfRegNum(Dst.getReg(), true));
       } else {
-        assert(0 && "Machine move no supported yet.");
+        LLVM_UNREACHABLE("Machine move no supported yet.");
       }
     } else {
       unsigned Reg = RI->getDwarfRegNum(Src.getReg(), true);
@@ -761,7 +762,7 @@
         
         FinalSize += TargetAsmInfo::getULEB128Size(Offset);
       } else {
-        assert(0 && "Machine move no supported yet.");
+        LLVM_UNREACHABLE("Machine move no supported yet.");
       }
     } else if (Src.isReg() &&
       Src.getReg() == MachineLocation::VirtualFP) {
@@ -770,7 +771,7 @@
         unsigned RegNum = RI->getDwarfRegNum(Dst.getReg(), true);
         FinalSize += TargetAsmInfo::getULEB128Size(RegNum);
       } else {
-        assert(0 && "Machine move no supported yet.");
+        LLVM_UNREACHABLE("Machine move no supported yet.");
       }
     } else {
       unsigned Reg = RI->getDwarfRegNum(Src.getReg(), true);
diff --git a/lib/Linker/LinkItems.cpp b/lib/Linker/LinkItems.cpp
index dc0f7c1..a4e7db5 100644
--- a/lib/Linker/LinkItems.cpp
+++ b/lib/Linker/LinkItems.cpp
@@ -14,6 +14,7 @@
 
 #include "llvm/Linker.h"
 #include "llvm/Module.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Bitcode/ReaderWriter.h"
 
@@ -80,7 +81,7 @@
   std::string Magic;
   Pathname.getMagicNumber(Magic, 64);
   switch (sys::IdentifyFileType(Magic.c_str(), 64)) {
-    default: assert(0 && "Bad file type identification");
+    default: LLVM_UNREACHABLE("Bad file type identification");
     case sys::Unknown_FileType:
       return warning("Supposed library '" + Lib + "' isn't a library.");
 
@@ -178,7 +179,7 @@
   std::string Magic;
   File.getMagicNumber(Magic, 64);
   switch (sys::IdentifyFileType(Magic.c_str(), 64)) {
-    default: assert(0 && "Bad file type identification");
+    default: LLVM_UNREACHABLE("Bad file type identification");
     case sys::Unknown_FileType:
       return warning("Ignoring file '" + File.toString() + 
                    "' because does not contain bitcode.");
diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index a69f724..3b1fceb 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Instructions.h"
 #include "llvm/Assembly/Writer.h"
 #include "llvm/Support/Streams.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/System/Path.h"
 #include "llvm/ADT/DenseMap.h"
 #include <sstream>
@@ -392,7 +393,7 @@
       Result = CE->getWithOperands(Ops);
     } else {
       assert(!isa<GlobalValue>(CPV) && "Unmapped global?");
-      assert(0 && "Unknown type of derived type constant value!");
+      LLVM_UNREACHABLE("Unknown type of derived type constant value!");
     }
   } else if (isa<InlineAsm>(In)) {
     Result = const_cast<Value*>(In);
@@ -409,7 +410,7 @@
   PrintMap(ValueMap);
 
   cerr << "Couldn't remap value: " << (void*)In << " " << *In << "\n";
-  assert(0 && "Couldn't remap value!");
+  LLVM_UNREACHABLE("Couldn't remap value!");
 #endif
   return 0;
 }
@@ -899,9 +900,9 @@
             // Nothing is required, mapped values will take the new global
             // automatically.
           } else if (DGVar->hasAppendingLinkage()) {
-            assert(0 && "Appending linkage unimplemented!");
+            LLVM_UNREACHABLE("Appending linkage unimplemented!");
           } else {
-            assert(0 && "Unknown linkage!");
+            LLVM_UNREACHABLE("Unknown linkage!");
           }
         } else {
           // Copy the initializer over now...
diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 9640fd9..172ae9e 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -14,7 +14,9 @@
 #include "llvm/MC/MCSection.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/MCValue.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
+
 using namespace llvm;
 
 namespace {
@@ -186,7 +188,7 @@
   // Need target hooks to know how to print this.
   switch (Size) {
   default:
-    assert(0 && "Invalid size for machine code value!");
+    LLVM_UNREACHABLE("Invalid size for machine code value!");
   case 1: OS << ".byte"; break;
   case 2: OS << ".short"; break;
   case 4: OS << ".long"; break;
@@ -207,9 +209,9 @@
 
   switch (ValueSize) {
   default:
-    assert(0 && "Invalid size for machine code value!");
+    LLVM_UNREACHABLE("Invalid size for machine code value!");
   case 8:
-    assert(0 && "Unsupported alignment size!");
+    LLVM_UNREACHABLE("Unsupported alignment size!");
   case 1: OS << (IsPow2 ? ".p2align" : ".balign"); break;
   case 2: OS << (IsPow2 ? ".p2alignw" : ".balignw"); break;
   case 4: OS << (IsPow2 ? ".p2alignl" : ".balignl"); break;
diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index 3b03c54..29bf0b4 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -14,6 +14,7 @@
 
 #include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/FoldingSet.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include <cstring>
 
@@ -1068,7 +1069,7 @@
 
   switch (rounding_mode) {
   default:
-    assert(0);
+    llvm_unreachable();
 
   case rmNearestTiesToAway:
     return lost_fraction == lfExactlyHalf || lost_fraction == lfMoreThanHalf;
@@ -1207,7 +1208,7 @@
 {
   switch (convolve(category, rhs.category)) {
   default:
-    assert(0);
+    llvm_unreachable();
 
   case convolve(fcNaN, fcZero):
   case convolve(fcNaN, fcNormal):
@@ -1331,7 +1332,7 @@
 {
   switch (convolve(category, rhs.category)) {
   default:
-    assert(0);
+    llvm_unreachable();
 
   case convolve(fcNaN, fcZero):
   case convolve(fcNaN, fcNormal):
@@ -1373,7 +1374,7 @@
 {
   switch (convolve(category, rhs.category)) {
   default:
-    assert(0);
+    llvm_unreachable();
 
   case convolve(fcNaN, fcZero):
   case convolve(fcNaN, fcNormal):
@@ -1415,7 +1416,7 @@
 {
   switch (convolve(category, rhs.category)) {
   default:
-    assert(0);
+    llvm_unreachable();
 
   case convolve(fcNaN, fcZero):
   case convolve(fcNaN, fcNormal):
@@ -1692,7 +1693,7 @@
 
   switch (convolve(category, rhs.category)) {
   default:
-    assert(0);
+    llvm_unreachable();
 
   case convolve(fcNaN, fcZero):
   case convolve(fcNaN, fcNormal):
@@ -2929,7 +2930,7 @@
   else if (api.getBitWidth()==128 && !isIEEE)
     return initFromPPCDoubleDoubleAPInt(api);
   else
-    assert(0);
+    llvm_unreachable();
 }
 
 APFloat::APFloat(const APInt& api, bool isIEEE)
diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp
index 30dc352..bd5abec 100644
--- a/lib/Support/APInt.cpp
+++ b/lib/Support/APInt.cpp
@@ -17,6 +17,7 @@
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cmath>
@@ -1386,7 +1387,7 @@
     else
       return x_old + 1;
   } else
-    assert(0 && "Error in APInt::sqrt computation");
+    LLVM_UNREACHABLE("Error in APInt::sqrt computation");
   return x_old + 1;
 }
 
@@ -2032,7 +2033,7 @@
     char cdigit = str[i];
     if (radix == 16) {
       if (!isxdigit(cdigit))
-        assert(0 && "Invalid hex digit in string");
+        LLVM_UNREACHABLE("Invalid hex digit in string");
       if (isdigit(cdigit))
         digit = cdigit - '0';
       else if (cdigit >= 'a')
@@ -2040,7 +2041,7 @@
       else if (cdigit >= 'A')
         digit = cdigit - 'A' + 10;
       else
-        assert(0 && "huh? we shouldn't get here");
+        LLVM_UNREACHABLE("huh? we shouldn't get here");
     } else if (isdigit(cdigit)) {
       digit = cdigit - '0';
       assert((radix == 10 ||
@@ -2048,7 +2049,7 @@
               (radix == 2 && (digit == 0 || digit == 1))) &&
              "Invalid digit in string for given radix");
     } else {
-      assert(0 && "Invalid character in digit string");
+      LLVM_UNREACHABLE("Invalid character in digit string");
     }
 
     // Shift or multiply the value by the radix
diff --git a/lib/Support/CommandLine.cpp b/lib/Support/CommandLine.cpp
index 0fe949c..400241f 100644
--- a/lib/Support/CommandLine.cpp
+++ b/lib/Support/CommandLine.cpp
@@ -693,7 +693,7 @@
           ValNo++;
           break;
         default:
-          assert(0 && "Internal error, unexpected NumOccurrences flag in "
+          LLVM_UNREACHABLE("Internal error, unexpected NumOccurrences flag in "
                  "positional argument processing!");
         }
       }
diff --git a/lib/Support/Dwarf.cpp b/lib/Support/Dwarf.cpp
index fa99035..c2ce680 100644
--- a/lib/Support/Dwarf.cpp
+++ b/lib/Support/Dwarf.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/Dwarf.h"
+#include "llvm/Support/ErrorHandling.h"
 
 #include <cassert>
 
@@ -83,7 +84,7 @@
     case DW_TAG_lo_user:                   return "DW_TAG_lo_user";
     case DW_TAG_hi_user:                   return "DW_TAG_hi_user";
   }
-  assert(0 && "Unknown Dwarf Tag");
+  LLVM_UNREACHABLE("Unknown Dwarf Tag");
   return "";
 }
 
@@ -94,7 +95,7 @@
     case DW_CHILDREN_no:                   return "CHILDREN_no";
     case DW_CHILDREN_yes:                  return "CHILDREN_yes";
   }
-  assert(0 && "Unknown Dwarf ChildrenFlag");
+  LLVM_UNREACHABLE("Unknown Dwarf ChildrenFlag");
   return "";
 }
 
@@ -205,7 +206,7 @@
     case DW_AT_APPLE_major_runtime_vers:   return "DW_AT_APPLE_major_runtime_vers";
     case DW_AT_APPLE_runtime_class:        return "DW_AT_APPLE_runtime_class";
   }
-  assert(0 && "Unknown Dwarf Attribute");
+  LLVM_UNREACHABLE("Unknown Dwarf Attribute");
   return "";
 }
 
@@ -235,7 +236,7 @@
     case DW_FORM_ref_udata:                return "FORM_ref_udata";
     case DW_FORM_indirect:                 return "FORM_indirect";
   }
-  assert(0 && "Unknown Dwarf Form Encoding");
+  LLVM_UNREACHABLE("Unknown Dwarf Form Encoding");
   return "";
 }
 
@@ -310,7 +311,7 @@
     case DW_OP_lo_user:                    return "OP_lo_user";
     case DW_OP_hi_user:                    return "OP_hi_user";
   }
-  assert(0 && "Unknown Dwarf Operation Encoding");
+  LLVM_UNREACHABLE("Unknown Dwarf Operation Encoding");
   return "";
 }
 
@@ -336,7 +337,7 @@
     case DW_ATE_lo_user:                   return "ATE_lo_user";
     case DW_ATE_hi_user:                   return "ATE_hi_user";
   }
-  assert(0 && "Unknown Dwarf Attribute Encoding");
+  LLVM_UNREACHABLE("Unknown Dwarf Attribute Encoding");
   return "";
 }
 
@@ -350,7 +351,7 @@
     case DW_DS_leading_separate:           return "DS_leading_separate";
     case DW_DS_trailing_separate:          return "DS_trailing_separate";
   }
-  assert(0 && "Unknown Dwarf Decimal Sign Attribute");
+  LLVM_UNREACHABLE("Unknown Dwarf Decimal Sign Attribute");
   return "";
 }
 
@@ -364,7 +365,7 @@
     case DW_END_lo_user:                   return "END_lo_user";
     case DW_END_hi_user:                   return "END_hi_user";
   }
-  assert(0 && "Unknown Dwarf Endianity");
+  LLVM_UNREACHABLE("Unknown Dwarf Endianity");
   return "";
 }
 
@@ -377,7 +378,7 @@
     case DW_ACCESS_protected:              return "ACCESS_protected";
     case DW_ACCESS_private:                return "ACCESS_private";
   }
-  assert(0 && "Unknown Dwarf Accessibility");
+  LLVM_UNREACHABLE("Unknown Dwarf Accessibility");
   return "";
 }
 
@@ -389,7 +390,7 @@
     case DW_VIS_exported:                  return "VIS_exported";
     case DW_VIS_qualified:                 return "VIS_qualified";
   }
-  assert(0 && "Unknown Dwarf Visibility");
+  LLVM_UNREACHABLE("Unknown Dwarf Visibility");
   return "";
 }
 
@@ -401,7 +402,7 @@
     case DW_VIRTUALITY_virtual:            return "VIRTUALITY_virtual";
     case DW_VIRTUALITY_pure_virtual:       return "VIRTUALITY_pure_virtual";
   }
-  assert(0 && "Unknown Dwarf Virtuality");
+  LLVM_UNREACHABLE("Unknown Dwarf Virtuality");
   return "";
 }
 
@@ -431,7 +432,7 @@
     case DW_LANG_lo_user:                  return "LANG_lo_user";
     case DW_LANG_hi_user:                  return "LANG_hi_user";
   }
-  assert(0 && "Unknown Dwarf Language");
+  LLVM_UNREACHABLE("Unknown Dwarf Language");
   return "";
 }
 
@@ -444,7 +445,7 @@
     case DW_ID_down_case:                  return "ID_down_case";
     case DW_ID_case_insensitive:           return "ID_case_insensitive";
   }
-  assert(0 && "Unknown Dwarf Identifier Case");
+  LLVM_UNREACHABLE("Unknown Dwarf Identifier Case");
   return "";
 }
 
@@ -458,7 +459,7 @@
     case DW_CC_lo_user:                    return "CC_lo_user";
     case DW_CC_hi_user:                    return "CC_hi_user";
   }
-  assert(0 && "Unknown Dwarf Calling Convention");
+  LLVM_UNREACHABLE("Unknown Dwarf Calling Convention");
   return "";
 }
 
@@ -471,7 +472,7 @@
     case DW_INL_declared_not_inlined:      return "INL_declared_not_inlined";
     case DW_INL_declared_inlined:          return "INL_declared_inlined";
   }
-  assert(0 && "Unknown Dwarf Inline Code");
+  LLVM_UNREACHABLE("Unknown Dwarf Inline Code");
   return "";
 }
 
@@ -482,7 +483,7 @@
     case DW_ORD_row_major:                 return "ORD_row_major";
     case DW_ORD_col_major:                 return "ORD_col_major";
   }
-  assert(0 && "Unknown Dwarf Array Order");
+  LLVM_UNREACHABLE("Unknown Dwarf Array Order");
   return "";
 }
 
@@ -493,7 +494,7 @@
     case DW_DSC_label:                     return "DSC_label";
     case DW_DSC_range:                     return "DSC_range";
   }
-  assert(0 && "Unknown Dwarf Discriminant Descriptor");
+  LLVM_UNREACHABLE("Unknown Dwarf Discriminant Descriptor");
   return "";
 }
 
@@ -514,7 +515,7 @@
     case DW_LNS_set_epilogue_begin:        return "LNS_set_epilogue_begin";
     case DW_LNS_set_isa:                   return "LNS_set_isa";
   }
-  assert(0 && "Unknown Dwarf Line Number Standard");
+  LLVM_UNREACHABLE("Unknown Dwarf Line Number Standard");
   return "";
 }
 
@@ -529,7 +530,7 @@
     case DW_LNE_lo_user:                   return "LNE_lo_user";
     case DW_LNE_hi_user:                   return "LNE_hi_user";
   }
-  assert(0 && "Unknown Dwarf Line Number Extended Opcode Encoding");
+  LLVM_UNREACHABLE("Unknown Dwarf Line Number Extended Opcode Encoding");
   return "";
 }
 
@@ -544,7 +545,7 @@
     case DW_MACINFO_end_file:              return "MACINFO_end_file";
     case DW_MACINFO_vendor_ext:            return "MACINFO_vendor_ext";
   }
-  assert(0 && "Unknown Dwarf Macinfo Type Encodings");
+  LLVM_UNREACHABLE("Unknown Dwarf Macinfo Type Encodings");
   return "";
 }
 
@@ -580,7 +581,7 @@
     case DW_CFA_lo_user:                   return "CFA_lo_user";
     case DW_CFA_hi_user:                   return "CFA_hi_user";
   }
-  assert(0 && "Unknown Dwarf Call Frame Instruction Encodings");
+  LLVM_UNREACHABLE("Unknown Dwarf Call Frame Instruction Encodings");
   return "";
 }
 
diff --git a/lib/Support/ErrorHandling.cpp b/lib/Support/ErrorHandling.cpp
index 2a5d906..f2e247c 100644
--- a/lib/Support/ErrorHandling.cpp
+++ b/lib/Support/ErrorHandling.cpp
@@ -44,7 +44,9 @@
   exit(1);
 }
 
-void llvm_unreachable(void) {
+void llvm_unreachable(const char *msg) {
+  if (msg)
+    errs() << msg << "\n";
   abort();
 }
 }
diff --git a/lib/Support/FoldingSet.cpp b/lib/Support/FoldingSet.cpp
index 41c730e..0f61067 100644
--- a/lib/Support/FoldingSet.cpp
+++ b/lib/Support/FoldingSet.cpp
@@ -15,6 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/FoldingSet.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include <cassert>
 #include <cstring>
@@ -50,7 +51,7 @@
   else if (sizeof(long) == sizeof(long long)) {
     AddInteger((unsigned long long)I);
   } else {
-    assert(0 && "unexpected sizeof(long)");
+    LLVM_UNREACHABLE("unexpected sizeof(long)");
   }
 }
 void FoldingSetNodeID::AddInteger(long long I) {
diff --git a/lib/Target/ARM/ARM.h b/lib/Target/ARM/ARM.h
index 0e654d8..471c212 100644
--- a/lib/Target/ARM/ARM.h
+++ b/lib/Target/ARM/ARM.h
@@ -15,6 +15,7 @@
 #ifndef TARGET_ARM_H
 #define TARGET_ARM_H
 
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetMachine.h"
 #include <cassert>
 
@@ -51,7 +52,7 @@
 
   inline static CondCodes getOppositeCondition(CondCodes CC){
     switch (CC) {
-    default: assert(0 && "Unknown condition code");
+    default: LLVM_UNREACHABLE("Unknown condition code");
     case EQ: return NE;
     case NE: return EQ;
     case HS: return LO;
@@ -72,7 +73,7 @@
 
 inline static const char *ARMCondCodeToString(ARMCC::CondCodes CC) {
   switch (CC) {
-  default: assert(0 && "Unknown condition code");
+  default: LLVM_UNREACHABLE("Unknown condition code");
   case ARMCC::EQ:  return "eq";
   case ARMCC::NE:  return "ne";
   case ARMCC::HS:  return "hs";
diff --git a/lib/Target/ARM/ARMAddressingModes.h b/lib/Target/ARM/ARMAddressingModes.h
index 6b90b73..40e3e86 100644
--- a/lib/Target/ARM/ARMAddressingModes.h
+++ b/lib/Target/ARM/ARMAddressingModes.h
@@ -15,6 +15,7 @@
 #define LLVM_TARGET_ARM_ARMADDRESSINGMODES_H
 
 #include "llvm/CodeGen/SelectionDAGNodes.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include <cassert>
 
@@ -37,7 +38,7 @@
   
   static inline const char *getShiftOpcStr(ShiftOpc Op) {
     switch (Op) {
-    default: assert(0 && "Unknown shift opc!");
+    default: LLVM_UNREACHABLE("Unknown shift opc!");
     case ARM_AM::asr: return "asr";
     case ARM_AM::lsl: return "lsl";
     case ARM_AM::lsr: return "lsr";
@@ -70,7 +71,7 @@
 
   static inline const char *getAMSubModeStr(AMSubMode Mode) {
     switch (Mode) {
-    default: assert(0 && "Unknown addressing sub-mode!");
+    default: LLVM_UNREACHABLE("Unknown addressing sub-mode!");
     case ARM_AM::ia: return "ia";
     case ARM_AM::ib: return "ib";
     case ARM_AM::da: return "da";
@@ -80,7 +81,7 @@
 
   static inline const char *getAMSubModeAltStr(AMSubMode Mode, bool isLD) {
     switch (Mode) {
-    default: assert(0 && "Unknown addressing sub-mode!");
+    default: LLVM_UNREACHABLE("Unknown addressing sub-mode!");
     case ARM_AM::ia: return isLD ? "fd" : "ea";
     case ARM_AM::ib: return isLD ? "ed" : "fa";
     case ARM_AM::da: return isLD ? "fa" : "ed";
diff --git a/lib/Target/ARM/ARMBaseInstrInfo.cpp b/lib/Target/ARM/ARMBaseInstrInfo.cpp
index d7ba73c..9bca6a7 100644
--- a/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -23,6 +23,7 @@
 #include "llvm/CodeGen/MachineJumpTableInfo.h"
 #include "llvm/Target/TargetAsmInfo.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
 static cl::opt<bool>
@@ -433,8 +434,7 @@
       return 0;
     switch (MI->getOpcode()) {
     default:
-      assert(0 && "Unknown or unset size field for instr!");
-      break;
+      LLVM_UNREACHABLE("Unknown or unset size field for instr!");
     case TargetInstrInfo::IMPLICIT_DEF:
     case TargetInstrInfo::DECLARE:
     case TargetInstrInfo::DBG_LABEL:
diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index 377de19..c93473d 100644
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -707,12 +707,12 @@
 }
 
 unsigned ARMBaseRegisterInfo::getEHExceptionRegister() const {
-  assert(0 && "What is the exception register");
+  LLVM_UNREACHABLE("What is the exception register");
   return 0;
 }
 
 unsigned ARMBaseRegisterInfo::getEHHandlerRegister() const {
-  assert(0 && "What is the exception handler register");
+  LLVM_UNREACHABLE("What is the exception handler register");
   return 0;
 }
 
diff --git a/lib/Target/ARM/ARMConstantIslandPass.cpp b/lib/Target/ARM/ARMConstantIslandPass.cpp
index 34c9d70..1f2376e 100644
--- a/lib/Target/ARM/ARMConstantIslandPass.cpp
+++ b/lib/Target/ARM/ARMConstantIslandPass.cpp
@@ -24,6 +24,7 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/Statistic.h"
@@ -448,7 +449,7 @@
               Bits = 8;  // Taking the address of a CP entry.
               break;
             }
-            assert(0 && "Unknown addressing mode for CP reference!");
+            LLVM_UNREACHABLE("Unknown addressing mode for CP reference!");
           case ARMII::AddrMode1: // AM1: 8 bits << 2
             Bits = 8;
             Scale = 4;  // Taking the address of a CP entry.
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 5c604a9..dec7a72 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -470,7 +470,7 @@
 /// IntCCToARMCC - Convert a DAG integer condition code to an ARM CC
 static ARMCC::CondCodes IntCCToARMCC(ISD::CondCode CC) {
   switch (CC) {
-  default: assert(0 && "Unknown condition code!");
+  default: LLVM_UNREACHABLE("Unknown condition code!");
   case ISD::SETNE:  return ARMCC::NE;
   case ISD::SETEQ:  return ARMCC::EQ;
   case ISD::SETGT:  return ARMCC::GT;
@@ -492,7 +492,7 @@
   bool Invert = false;
   CondCode2 = ARMCC::AL;
   switch (CC) {
-  default: assert(0 && "Unknown FP condition!");
+  default: LLVM_UNREACHABLE("Unknown FP condition!");
   case ISD::SETEQ:
   case ISD::SETOEQ: CondCode = ARMCC::EQ; break;
   case ISD::SETGT:
@@ -661,7 +661,7 @@
                                                  bool Return) const {
   switch (CC) {
   default:
-   assert(0 && "Unsupported calling convention");
+   LLVM_UNREACHABLE("Unsupported calling convention");
   case CallingConv::C:
   case CallingConv::Fast:
    // Use target triple & subtarget features to do actual dispatch.
@@ -745,7 +745,7 @@
     }
 
     switch (VA.getLocInfo()) {
-    default: assert(0 && "Unknown loc info!");
+    default: LLVM_UNREACHABLE("Unknown loc info!");
     case CCValAssign::Full: break;
     case CCValAssign::BCvt:
       Val = DAG.getNode(ISD::BIT_CONVERT, dl, VA.getValVT(), Val);
@@ -858,7 +858,7 @@
 
     // Promote the value if needed.
     switch (VA.getLocInfo()) {
-    default: assert(0 && "Unknown loc info!");
+    default: LLVM_UNREACHABLE("Unknown loc info!");
     case CCValAssign::Full: break;
     case CCValAssign::SExt:
       Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
@@ -1060,7 +1060,7 @@
     SDValue Arg = Op.getOperand(realRVLocIdx*2+1);
 
     switch (VA.getLocInfo()) {
-    default: assert(0 && "Unknown loc info!");
+    default: LLVM_UNREACHABLE("Unknown loc info!");
     case CCValAssign::Full: break;
     case CCValAssign::BCvt:
       Arg = DAG.getNode(ISD::BIT_CONVERT, dl, VA.getLocVT(), Arg);
@@ -1442,7 +1442,7 @@
       // to 32 bits.  Insert an assert[sz]ext to capture this, then
       // truncate to the right size.
       switch (VA.getLocInfo()) {
-      default: assert(0 && "Unknown loc info!");
+      default: LLVM_UNREACHABLE("Unknown loc info!");
       case CCValAssign::Full: break;
       case CCValAssign::BCvt:
         ArgValue = DAG.getNode(ISD::BIT_CONVERT, dl, VA.getValVT(), ArgValue);
@@ -2006,7 +2006,7 @@
 
   if (Op.getOperand(1).getValueType().isFloatingPoint()) {
     switch (SetCCOpcode) {
-    default: assert(0 && "Illegal FP comparison"); break;
+    default: LLVM_UNREACHABLE("Illegal FP comparison"); break;
     case ISD::SETUNE:
     case ISD::SETNE:  Invert = true; // Fallthrough
     case ISD::SETOEQ:
@@ -2045,7 +2045,7 @@
   } else {
     // Integer comparisons.
     switch (SetCCOpcode) {
-    default: assert(0 && "Illegal integer comparison"); break;
+    default: LLVM_UNREACHABLE("Illegal integer comparison"); break;
     case ISD::SETNE:  Invert = true;
     case ISD::SETEQ:  Opc = ARMISD::VCEQ; break;
     case ISD::SETLT:  Swap = true;
@@ -2149,7 +2149,7 @@
   }
 
   default:
-    assert(0 && "unexpected size for isVMOVSplat");
+    LLVM_UNREACHABLE("unexpected size for isVMOVSplat");
     break;
   }
 
@@ -2191,7 +2191,7 @@
     case 16: CanonicalVT = MVT::v4i16; break;
     case 32: CanonicalVT = MVT::v2i32; break;
     case 64: CanonicalVT = MVT::v1i64; break;
-    default: assert(0 && "unexpected splat element type"); break;
+    default: LLVM_UNREACHABLE("unexpected splat element type"); break;
     }
   } else {
     assert(VT.is128BitVector() && "unknown splat vector size");
@@ -2200,7 +2200,7 @@
     case 16: CanonicalVT = MVT::v8i16; break;
     case 32: CanonicalVT = MVT::v4i32; break;
     case 64: CanonicalVT = MVT::v2i64; break;
-    default: assert(0 && "unexpected splat element type"); break;
+    default: LLVM_UNREACHABLE("unexpected splat element type"); break;
     }
   }
 
@@ -2303,7 +2303,7 @@
                                            SelectionDAG &DAG) {
   switch (N->getOpcode()) {
   default:
-    assert(0 && "Don't know how to custom expand this!");
+    LLVM_UNREACHABLE("Don't know how to custom expand this!");
     return;
   case ISD::BIT_CONVERT:
     Results.push_back(ExpandBIT_CONVERT(N, DAG));
@@ -2628,7 +2628,7 @@
       LLVM_UNREACHABLE("invalid shift count for narrowing vector shift intrinsic");
 
     default:
-      assert(0 && "unhandled vector shift");
+      LLVM_UNREACHABLE("unhandled vector shift");
     }
 
     switch (IntNo) {
@@ -2720,7 +2720,7 @@
   int64_t Cnt;
 
   switch (N->getOpcode()) {
-  default: assert(0 && "unexpected shift opcode");
+  default: LLVM_UNREACHABLE("unexpected shift opcode");
 
   case ISD::SHL:
     if (isVShiftLImm(N->getOperand(1), VT, false, Cnt))
@@ -2763,7 +2763,7 @@
 
       unsigned Opc = 0;
       switch (N->getOpcode()) {
-      default: assert(0 && "unexpected opcode");
+      default: LLVM_UNREACHABLE("unexpected opcode");
       case ISD::SIGN_EXTEND:
         Opc = ARMISD::VGETLANEs;
         break;
diff --git a/lib/Target/Alpha/AlphaISelDAGToDAG.cpp b/lib/Target/Alpha/AlphaISelDAGToDAG.cpp
index 6fa05fc..977e621 100644
--- a/lib/Target/Alpha/AlphaISelDAGToDAG.cpp
+++ b/lib/Target/Alpha/AlphaISelDAGToDAG.cpp
@@ -338,7 +338,7 @@
       bool rev = false;
       bool inv = false;
       switch(CC) {
-      default: DEBUG(N->dump(CurDAG)); assert(0 && "Unknown FP comparison!");
+      default: DEBUG(N->dump(CurDAG)); LLVM_UNREACHABLE("Unknown FP comparison!");
       case ISD::SETEQ: case ISD::SETOEQ: case ISD::SETUEQ:
         Opc = Alpha::CMPTEQ; break;
       case ISD::SETLT: case ISD::SETOLT: case ISD::SETULT: 
@@ -472,7 +472,7 @@
      } else if (TypeOperands[i] == MVT::f64) {
        Opc = Alpha::STT;
      } else
-       assert(0 && "Unknown operand"); 
+       LLVM_UNREACHABLE("Unknown operand"); 
 
      SDValue Ops[] = { CallOperands[i],  getI64Imm((i - 6) * 8), 
                        CurDAG->getCopyFromReg(Chain, dl, Alpha::R30, MVT::i64),
@@ -489,7 +489,7 @@
                                     CallOperands[i], InFlag);
        InFlag = Chain.getValue(1);
      } else
-       assert(0 && "Unknown operand"); 
+       LLVM_UNREACHABLE("Unknown operand"); 
    }
 
    // Finally, once everything is in registers to pass to the call, emit the
@@ -512,7 +512,7 @@
    std::vector<SDValue> CallResults;
   
    switch (N->getValueType(0).getSimpleVT()) {
-   default: assert(0 && "Unexpected ret value!");
+   default: LLVM_UNREACHABLE("Unexpected ret value!");
      case MVT::Other: break;
    case MVT::i64:
      Chain = CurDAG->getCopyFromReg(Chain, dl, 
diff --git a/lib/Target/Alpha/AlphaISelLowering.cpp b/lib/Target/Alpha/AlphaISelLowering.cpp
index 49fb262..2893536 100644
--- a/lib/Target/Alpha/AlphaISelLowering.cpp
+++ b/lib/Target/Alpha/AlphaISelLowering.cpp
@@ -380,7 +380,7 @@
   for (unsigned i = 0, e = Args.size(); i != e; ++i)
   {
     switch (getValueType(Args[i].Ty).getSimpleVT()) {
-    default: assert(0 && "Unexpected ValueType for argument!");
+    default: LLVM_UNREACHABLE("Unexpected ValueType for argument!");
     case MVT::i1:
     case MVT::i8:
     case MVT::i16:
@@ -476,7 +476,7 @@
 SDValue AlphaTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) {
   DebugLoc dl = Op.getDebugLoc();
   switch (Op.getOpcode()) {
-  default: assert(0 && "Wasn't expecting to be able to lower this!");
+  default: LLVM_UNREACHABLE("Wasn't expecting to be able to lower this!");
   case ISD::FORMAL_ARGUMENTS: return LowerFORMAL_ARGUMENTS(Op, DAG, 
                                                            VarArgsBase,
                                                            VarArgsOffset);
@@ -527,7 +527,7 @@
     return Lo;
   }
   case ISD::GlobalTLSAddress:
-    assert(0 && "TLS not implemented for Alpha.");
+    LLVM_UNREACHABLE("TLS not implemented for Alpha.");
   case ISD::GlobalAddress: {
     GlobalAddressSDNode *GSDN = cast<GlobalAddressSDNode>(Op);
     GlobalValue *GV = GSDN->getGlobal();
diff --git a/lib/Target/Alpha/AlphaInstrInfo.cpp b/lib/Target/Alpha/AlphaInstrInfo.cpp
index 62b5d4c..139a4db 100644
--- a/lib/Target/Alpha/AlphaInstrInfo.cpp
+++ b/lib/Target/Alpha/AlphaInstrInfo.cpp
@@ -332,7 +332,7 @@
   case Alpha::FBLE: return Alpha::FBGT;
   case Alpha::FBLT: return Alpha::FBGE;
   default:
-    assert(0 && "Unknown opcode");
+    LLVM_UNREACHABLE("Unknown opcode");
   }
   return 0; // Not reached
 }
diff --git a/lib/Target/Alpha/AlphaJITInfo.cpp b/lib/Target/Alpha/AlphaJITInfo.cpp
index c62ab75..8919dc0 100644
--- a/lib/Target/Alpha/AlphaJITInfo.cpp
+++ b/lib/Target/Alpha/AlphaJITInfo.cpp
@@ -72,7 +72,7 @@
 
 void AlphaJITInfo::replaceMachineCodeForFunction(void *Old, void *New) {
   //FIXME
-  assert(0);
+  llvm_unreachable();
 }
 
 static TargetJITInfo::JITCompilerFn JITCompilerFunction;
@@ -241,7 +241,7 @@
     long idx = 0;
     bool doCommon = true;
     switch ((Alpha::RelocationType)MR->getRelocationType()) {
-    default: assert(0 && "Unknown relocation type!");
+    default: LLVM_UNREACHABLE("Unknown relocation type!");
     case Alpha::reloc_literal:
       //This is a LDQl
       idx = MR->getGOTIndex();
@@ -281,7 +281,7 @@
         DOUT << "LDA: " << idx << "\n";
         break;
       default:
-        assert(0 && "Cannot handle gpdist yet");
+        LLVM_UNREACHABLE("Cannot handle gpdist yet");
       }
       break;
     case Alpha::reloc_bsr: {
diff --git a/lib/Target/Alpha/AlphaRegisterInfo.cpp b/lib/Target/Alpha/AlphaRegisterInfo.cpp
index 1194a0f..f1e651c 100644
--- a/lib/Target/Alpha/AlphaRegisterInfo.cpp
+++ b/lib/Target/Alpha/AlphaRegisterInfo.cpp
@@ -307,7 +307,7 @@
 }
 
 unsigned AlphaRegisterInfo::getRARegister() const {
-  assert(0 && "What is the return address register");
+  LLVM_UNREACHABLE("What is the return address register");
   return 0;
 }
 
@@ -316,17 +316,17 @@
 }
 
 unsigned AlphaRegisterInfo::getEHExceptionRegister() const {
-  assert(0 && "What is the exception register");
+  LLVM_UNREACHABLE("What is the exception register");
   return 0;
 }
 
 unsigned AlphaRegisterInfo::getEHHandlerRegister() const {
-  assert(0 && "What is the exception handler register");
+  LLVM_UNREACHABLE("What is the exception handler register");
   return 0;
 }
 
 int AlphaRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
-  assert(0 && "What is the dwarf register number");
+  LLVM_UNREACHABLE("What is the dwarf register number");
   return -1;
 }
 
diff --git a/lib/Target/Alpha/AsmPrinter/AlphaAsmPrinter.cpp b/lib/Target/Alpha/AsmPrinter/AlphaAsmPrinter.cpp
index 11f177d..cc278b7 100644
--- a/lib/Target/Alpha/AsmPrinter/AlphaAsmPrinter.cpp
+++ b/lib/Target/Alpha/AsmPrinter/AlphaAsmPrinter.cpp
@@ -155,7 +155,7 @@
 
   EmitAlignment(MF.getAlignment(), F);
   switch (F->getLinkage()) {
-  default: assert(0 && "Unknown linkage type!");
+  default: LLVM_UNREACHABLE( "Unknown linkage type!");
   case Function::InternalLinkage:  // Symbols default to internal.
   case Function::PrivateLinkage:
     break;
diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index 70495d0..f922146 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -287,11 +287,11 @@
     void visitBranchInst(BranchInst &I);
     void visitSwitchInst(SwitchInst &I);
     void visitInvokeInst(InvokeInst &I) {
-      assert(0 && "Lowerinvoke pass didn't work!");
+      LLVM_UNREACHABLE("Lowerinvoke pass didn't work!");
     }
 
     void visitUnwindInst(UnwindInst &I) {
-      assert(0 && "Lowerinvoke pass didn't work!");
+      LLVM_UNREACHABLE("Lowerinvoke pass didn't work!");
     }
     void visitUnreachableInst(UnreachableInst &I);
 
@@ -921,7 +921,7 @@
       Out << ')';
       break;
     default:
-      assert(0 && "Invalid cast opcode");
+      LLVM_UNREACHABLE("Invalid cast opcode");
   }
 
   // Print the source type cast
@@ -951,7 +951,7 @@
     case Instruction::FPToUI:
       break; // These don't need a source cast.
     default:
-      assert(0 && "Invalid cast opcode");
+      LLVM_UNREACHABLE("Invalid cast opcode");
       break;
   }
 }
@@ -1060,10 +1060,10 @@
           case ICmpInst::ICMP_UGT: Out << " > "; break;
           case ICmpInst::ICMP_SGE:
           case ICmpInst::ICMP_UGE: Out << " >= "; break;
-          default: assert(0 && "Illegal ICmp predicate");
+          default: LLVM_UNREACHABLE("Illegal ICmp predicate");
         }
         break;
-      default: assert(0 && "Illegal opcode here!");
+      default: LLVM_UNREACHABLE("Illegal opcode here!");
       }
       printConstantWithCast(CE->getOperand(1), CE->getOpcode());
       if (NeedsClosingParens)
@@ -1081,7 +1081,7 @@
       else {
         const char* op = 0;
         switch (CE->getPredicate()) {
-        default: assert(0 && "Illegal FCmp predicate");
+        default: LLVM_UNREACHABLE("Illegal FCmp predicate");
         case FCmpInst::FCMP_ORD: op = "ord"; break;
         case FCmpInst::FCMP_UNO: op = "uno"; break;
         case FCmpInst::FCMP_UEQ: op = "ueq"; break;
@@ -2123,7 +2123,7 @@
     << "}; /* Long double constant */\n";
     
   } else {
-    assert(0 && "Unknown float type!");
+    LLVM_UNREACHABLE("Unknown float type!");
   }
 }
 
@@ -2740,7 +2740,7 @@
 
   const char* op = 0;
   switch (I.getPredicate()) {
-  default: assert(0 && "Illegal FCmp predicate");
+  default: LLVM_UNREACHABLE("Illegal FCmp predicate");
   case FCmpInst::FCMP_ORD: op = "ord"; break;
   case FCmpInst::FCMP_UNO: op = "uno"; break;
   case FCmpInst::FCMP_UEQ: op = "ueq"; break;
@@ -2768,7 +2768,7 @@
 
 static const char * getFloatBitCastField(const Type *Ty) {
   switch (Ty->getTypeID()) {
-    default: assert(0 && "Invalid Type");
+    default: LLVM_UNREACHABLE("Invalid Type");
     case Type::FloatTyID:  return "Float";
     case Type::DoubleTyID: return "Double";
     case Type::IntegerTyID: {
@@ -3131,7 +3131,7 @@
     Out << ')';  
     // Multiple GCC builtins multiplex onto this intrinsic.
     switch (cast<ConstantInt>(I.getOperand(3))->getZExtValue()) {
-    default: assert(0 && "Invalid llvm.x86.sse.cmp!");
+    default: LLVM_UNREACHABLE("Invalid llvm.x86.sse.cmp!");
     case 0: Out << "__builtin_ia32_cmpeq"; break;
     case 1: Out << "__builtin_ia32_cmplt"; break;
     case 2: Out << "__builtin_ia32_cmple"; break;
@@ -3343,7 +3343,7 @@
 }
 
 void CWriter::visitMallocInst(MallocInst &I) {
-  assert(0 && "lowerallocations pass didn't work!");
+  LLVM_UNREACHABLE("lowerallocations pass didn't work!");
 }
 
 void CWriter::visitAllocaInst(AllocaInst &I) {
@@ -3360,7 +3360,7 @@
 }
 
 void CWriter::visitFreeInst(FreeInst &I) {
-  assert(0 && "lowerallocations pass didn't work!");
+  LLVM_UNREACHABLE("lowerallocations pass didn't work!");
 }
 
 void CWriter::printGEPExpression(Value *Ptr, gep_type_iterator I,
diff --git a/lib/Target/CellSPU/AsmPrinter/SPUAsmPrinter.cpp b/lib/Target/CellSPU/AsmPrinter/SPUAsmPrinter.cpp
index 4d51643..cc2965f 100644
--- a/lib/Target/CellSPU/AsmPrinter/SPUAsmPrinter.cpp
+++ b/lib/Target/CellSPU/AsmPrinter/SPUAsmPrinter.cpp
@@ -265,7 +265,7 @@
                && "Invalid negated immediate rotate 7-bit argument");
         O << -value;
       } else {
-        assert(0 &&"Invalid/non-immediate rotate amount in printRotateNeg7Imm");
+        LLVM_UNREACHABLE("Invalid/non-immediate rotate amount in printRotateNeg7Imm");
       }
     }
 
@@ -276,7 +276,7 @@
                && "Invalid negated immediate rotate 7-bit argument");
         O << -value;
       } else {
-        assert(0 &&"Invalid/non-immediate rotate amount in printRotateNeg7Imm");
+        LLVM_UNREACHABLE("Invalid/non-immediate rotate amount in printRotateNeg7Imm");
       }
     }
 
@@ -434,7 +434,7 @@
   EmitAlignment(MF.getAlignment(), F);
 
   switch (F->getLinkage()) {
-  default: assert(0 && "Unknown linkage type!");
+  default: LLVM_UNREACHABLE( "Unknown linkage type!");
   case Function::PrivateLinkage:
   case Function::InternalLinkage:  // Symbols default to internal.
     break;
diff --git a/lib/Target/CellSPU/SPUISelDAGToDAG.cpp b/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
index f9801d5..ddb9a36 100644
--- a/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
+++ b/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
@@ -378,7 +378,7 @@
         break;
       case 'v':   // not offsetable
 #if 1
-        assert(0 && "InlineAsmMemoryOperand 'v' constraint not handled.");
+        LLVM_UNREACHABLE("InlineAsmMemoryOperand 'v' constraint not handled.");
 #else
         SelectAddrIdxOnly(Op, Op, Op0, Op1);
 #endif
diff --git a/lib/Target/CellSPU/SPUISelLowering.cpp b/lib/Target/CellSPU/SPUISelLowering.cpp
index fe28b63..58a9b3a 100644
--- a/lib/Target/CellSPU/SPUISelLowering.cpp
+++ b/lib/Target/CellSPU/SPUISelLowering.cpp
@@ -875,7 +875,7 @@
     }
   }
 
-  assert(0 &&
+  LLVM_UNREACHABLE(
          "LowerConstantPool: Relocation model other than static"
          " not supported.");
   return SDValue();
@@ -907,7 +907,7 @@
     }
   }
 
-  assert(0 &&
+  LLVM_UNREACHABLE(
          "LowerJumpTable: Relocation model other than static not supported.");
   return SDValue();
 }
@@ -1139,7 +1139,7 @@
     PtrOff = DAG.getNode(ISD::ADD, dl, PtrVT, StackPtr, PtrOff);
 
     switch (Arg.getValueType().getSimpleVT()) {
-    default: assert(0 && "Unexpected ValueType for argument!");
+    default: LLVM_UNREACHABLE("Unexpected ValueType for argument!");
     case MVT::i8:
     case MVT::i16:
     case MVT::i32:
@@ -1271,7 +1271,7 @@
 
   // If the call has results, copy the values out of the ret val registers.
   switch (TheCall->getValueType(0).getSimpleVT()) {
-  default: assert(0 && "Unexpected ret value!");
+  default: LLVM_UNREACHABLE("Unexpected ret value!");
   case MVT::Other: break;
   case MVT::i32:
     if (TheCall->getValueType(1) == MVT::i32) {
@@ -1739,7 +1739,7 @@
   } else if (EltVT == MVT::i64 || EltVT == MVT::f64) {
     V2EltIdx0 = 2;
   } else
-    assert(0 && "Unhandled vector type in LowerVECTOR_SHUFFLE");
+    LLVM_UNREACHABLE("Unhandled vector type in LowerVECTOR_SHUFFLE");
 
   for (unsigned i = 0; i != MaxElts; ++i) {
     if (SVN->getMaskElt(i) < 0)
@@ -1835,7 +1835,7 @@
 
     // Create a constant vector:
     switch (Op.getValueType().getSimpleVT()) {
-    default: assert(0 && "Unexpected constant value type in "
+    default: LLVM_UNREACHABLE("Unexpected constant value type in "
                          "LowerSCALAR_TO_VECTOR");
     case MVT::v16i8: n_copies = 16; VT = MVT::i8; break;
     case MVT::v8i16: n_copies = 8; VT = MVT::i16; break;
@@ -1854,7 +1854,7 @@
   } else {
     // Otherwise, copy the value from one register to another:
     switch (Op0.getValueType().getSimpleVT()) {
-    default: assert(0 && "Unexpected value type in LowerSCALAR_TO_VECTOR");
+    default: LLVM_UNREACHABLE("Unexpected value type in LowerSCALAR_TO_VECTOR");
     case MVT::i8:
     case MVT::i16:
     case MVT::i32:
@@ -1881,13 +1881,13 @@
 
     // sanity checks:
     if (VT == MVT::i8 && EltNo >= 16)
-      assert(0 && "SPU LowerEXTRACT_VECTOR_ELT: i8 extraction slot > 15");
+      LLVM_UNREACHABLE("SPU LowerEXTRACT_VECTOR_ELT: i8 extraction slot > 15");
     else if (VT == MVT::i16 && EltNo >= 8)
-      assert(0 && "SPU LowerEXTRACT_VECTOR_ELT: i16 extraction slot > 7");
+      LLVM_UNREACHABLE("SPU LowerEXTRACT_VECTOR_ELT: i16 extraction slot > 7");
     else if (VT == MVT::i32 && EltNo >= 4)
-      assert(0 && "SPU LowerEXTRACT_VECTOR_ELT: i32 extraction slot > 4");
+      LLVM_UNREACHABLE("SPU LowerEXTRACT_VECTOR_ELT: i32 extraction slot > 4");
     else if (VT == MVT::i64 && EltNo >= 2)
-      assert(0 && "SPU LowerEXTRACT_VECTOR_ELT: i64 extraction slot > 2");
+      LLVM_UNREACHABLE("SPU LowerEXTRACT_VECTOR_ELT: i64 extraction slot > 2");
 
     if (EltNo == 0 && (VT == MVT::i32 || VT == MVT::i64)) {
       // i32 and i64: Element 0 is the preferred slot
@@ -2066,7 +2066,7 @@
   assert(Op.getValueType() == MVT::i8);
   switch (Opc) {
   default:
-    assert(0 && "Unhandled i8 math operator");
+    LLVM_UNREACHABLE("Unhandled i8 math operator");
     /*NOTREACHED*/
     break;
   case ISD::ADD: {
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index 06eb575..162e9fd 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -325,7 +325,7 @@
 
   void CppWriter::printVisibilityType(GlobalValue::VisibilityTypes VisType) {
     switch (VisType) {
-    default: assert(0 && "Unknown GVar visibility");
+    default: LLVM_UNREACHABLE("Unknown GVar visibility");
     case GlobalValue::DefaultVisibility:
       Out << "GlobalValue::DefaultVisibility";
       break;
@@ -844,7 +844,7 @@
         printConstant(CE->getOperand(0));
         Out << "Constant* " << constName << " = ConstantExpr::getCast(";
         switch (CE->getOpcode()) {
-        default: assert(0 && "Invalid cast opcode");
+        default: LLVM_UNREACHABLE("Invalid cast opcode");
         case Instruction::Trunc: Out << "Instruction::Trunc"; break;
         case Instruction::ZExt:  Out << "Instruction::ZExt"; break;
         case Instruction::SExt:  Out << "Instruction::SExt"; break;
diff --git a/lib/Target/DarwinTargetAsmInfo.cpp b/lib/Target/DarwinTargetAsmInfo.cpp
index d7d675a..6094976 100644
--- a/lib/Target/DarwinTargetAsmInfo.cpp
+++ b/lib/Target/DarwinTargetAsmInfo.cpp
@@ -17,6 +17,7 @@
 #include "llvm/Function.h"
 #include "llvm/GlobalVariable.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Mangler.h"
 #include "llvm/Target/DarwinTargetAsmInfo.h"
 #include "llvm/Target/TargetMachine.h"
@@ -151,7 +152,7 @@
             ConstDataCoalSection:
             MergeableConstSection(cast<GlobalVariable>(GV)));
    default:
-    assert(0 && "Unsuported section kind for global");
+    LLVM_UNREACHABLE("Unsuported section kind for global");
   }
 
   // FIXME: Do we have any extra special weird cases?
@@ -211,6 +212,6 @@
 std::string
 DarwinTargetAsmInfo::UniqueSectionForGlobal(const GlobalValue* GV,
                                                SectionKind::Kind kind) const {
-  assert(0 && "Darwin does not use unique sections");
+  LLVM_UNREACHABLE("Darwin does not use unique sections");
   return "";
 }
diff --git a/lib/Target/ELFTargetAsmInfo.cpp b/lib/Target/ELFTargetAsmInfo.cpp
index 8f6e96e..b513a60 100644
--- a/lib/Target/ELFTargetAsmInfo.cpp
+++ b/lib/Target/ELFTargetAsmInfo.cpp
@@ -18,6 +18,7 @@
 #include "llvm/GlobalVariable.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/ELFTargetAsmInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetData.h"
@@ -74,7 +75,7 @@
 
   if (const Function *F = dyn_cast<Function>(GV)) {
     switch (F->getLinkage()) {
-     default: assert(0 && "Unknown linkage type!");
+     default: LLVM_UNREACHABLE("Unknown linkage type!");
      case Function::PrivateLinkage:
      case Function::InternalLinkage:
      case Function::DLLExportLinkage:
@@ -123,11 +124,11 @@
        case SectionKind::ThreadBSS:
         return TLSBSSSection;
        default:
-        assert(0 && "Unsuported section kind for global");
+        LLVM_UNREACHABLE("Unsuported section kind for global");
       }
     }
   } else
-    assert(0 && "Unsupported global");
+    LLVM_UNREACHABLE("Unsupported global");
 
   return NULL;
 }
diff --git a/lib/Target/IA64/IA64ISelDAGToDAG.cpp b/lib/Target/IA64/IA64ISelDAGToDAG.cpp
index 739ae31..adb4c4b 100644
--- a/lib/Target/IA64/IA64ISelDAGToDAG.cpp
+++ b/lib/Target/IA64/IA64ISelDAGToDAG.cpp
@@ -215,7 +215,7 @@
     
     if(isFP) { // if this is an FP divide, we finish up here and exit early
       if(isModulus)
-        assert(0 && "Sorry, try another FORTRAN compiler.");
+        LLVM_UNREACHABLE("Sorry, try another FORTRAN compiler.");
  
       SDValue TmpE2, TmpY3, TmpQ0, TmpR0;
 
@@ -406,7 +406,7 @@
                                   APFloat(+1.0f) : APFloat(+1.0))) {
       V = CurDAG->getCopyFromReg(Chain, dl, IA64::F1, MVT::f64);
     } else
-      assert(0 && "Unexpected FP constant!");
+      LLVM_UNREACHABLE("Unexpected FP constant!");
     
     ReplaceUses(SDValue(N, 0), V);
     return 0;
@@ -468,7 +468,7 @@
 #ifndef NDEBUG
       N->dump(CurDAG);
 #endif
-      assert(0 && "Cannot load this type!");
+      LLVM_UNREACHABLE("Cannot load this type!");
     case MVT::i1: { // this is a bool
       Opc = IA64::LD1; // first we load a byte, then compare for != 0
       if(N->getValueType(0) == MVT::i1) { // XXX: early exit!
@@ -504,7 +504,7 @@
     unsigned Opc;
     if (ISD::isNON_TRUNCStore(N)) {
       switch (N->getOperand(1).getValueType().getSimpleVT()) {
-      default: assert(0 && "unknown type in store");
+      default: LLVM_UNREACHABLE("unknown type in store");
       case MVT::i1: { // this is a bool
         Opc = IA64::ST1; // we store either 0 or 1 as a byte 
         // first load zero!
@@ -524,7 +524,7 @@
       }
     } else { // Truncating store
       switch(ST->getMemoryVT().getSimpleVT()) {
-      default: assert(0 && "unknown type in truncstore");
+      default: LLVM_UNREACHABLE("unknown type in truncstore");
       case MVT::i8:  Opc = IA64::ST1;  break;
       case MVT::i16: Opc = IA64::ST2;  break;
       case MVT::i32: Opc = IA64::ST4;  break;
diff --git a/lib/Target/IA64/IA64ISelLowering.cpp b/lib/Target/IA64/IA64ISelLowering.cpp
index 1b661eb..094f8c2 100644
--- a/lib/Target/IA64/IA64ISelLowering.cpp
+++ b/lib/Target/IA64/IA64ISelLowering.cpp
@@ -194,7 +194,7 @@
 
         switch (getValueType(I->getType()).getSimpleVT()) {
           default:
-            assert(0 && "ERROR in LowerArgs: can't lower this type of arg.\n"); 
+            LLVM_UNREACHABLE("ERROR in LowerArgs: can't lower this type of arg.\n"); 
           case MVT::f32:
             // fixme? (well, will need to for weird FP structy stuff,
             // see intel ABI docs)
@@ -298,7 +298,7 @@
   // Finally, inform the code generator which regs we return values in.
   // (see the ISD::RET: case in the instruction selector)
   switch (getValueType(F.getReturnType()).getSimpleVT()) {
-  default: assert(0 && "i have no idea where to return this type!");
+  default: LLVM_UNREACHABLE("i have no idea where to return this type!");
   case MVT::isVoid: break;
   case MVT::i1:
   case MVT::i8:
@@ -362,7 +362,7 @@
       SDValue ValToStore(0, 0), ValToConvert(0, 0);
       unsigned ObjSize=8;
       switch (ObjectVT.getSimpleVT()) {
-      default: assert(0 && "unexpected argument type!");
+      default: LLVM_UNREACHABLE("unexpected argument type!");
       case MVT::i1:
       case MVT::i8:
       case MVT::i16:
@@ -493,7 +493,7 @@
   if (InFlag.getNode())
     CallOperands.push_back(InFlag);
   else
-    assert(0 && "this should never happen!\n");
+    LLVM_UNREACHABLE("this should never happen!\n");
 
   // to make way for a hack:
   Chain = DAG.getNode(IA64ISD::BRCALL, dl, NodeTys,
@@ -516,7 +516,7 @@
   SDValue RetVal;
   if (RetTyVT != MVT::isVoid) {
     switch (RetTyVT.getSimpleVT()) {
-    default: assert(0 && "Unknown value type to return!");
+    default: LLVM_UNREACHABLE("Unknown value type to return!");
     case MVT::i1: { // bools are just like other integers (returned in r8)
       // we *could* fall through to the truncate below, but this saves a
       // few redundant predicate ops
@@ -573,9 +573,9 @@
 LowerOperation(SDValue Op, SelectionDAG &DAG) {
   DebugLoc dl = Op.getDebugLoc();
   switch (Op.getOpcode()) {
-  default: assert(0 && "Should not custom lower this!");
+  default: LLVM_UNREACHABLE("Should not custom lower this!");
   case ISD::GlobalTLSAddress:
-    assert(0 && "TLS not implemented for IA64.");
+    LLVM_UNREACHABLE("TLS not implemented for IA64.");
   case ISD::RET: {
     SDValue AR_PFSVal, Copy;
     
diff --git a/lib/Target/IA64/IA64InstrInfo.cpp b/lib/Target/IA64/IA64InstrInfo.cpp
index 5f89d4f..0537c3e 100644
--- a/lib/Target/IA64/IA64InstrInfo.cpp
+++ b/lib/Target/IA64/IA64InstrInfo.cpp
@@ -16,6 +16,7 @@
 #include "IA64InstrBuilder.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "IA64GenInstrInfo.inc"
 using namespace llvm;
 
@@ -111,8 +112,8 @@
     BuildMI(MBB, MI, DL, get(IA64::ST8))
       .addFrameIndex(FrameIdx)
       .addReg(IA64::r2);
-  } else assert(0 &&
-      "sorry, I don't know how to store this sort of reg in the stack\n");
+  } else 
+    LLVM_UNREACHABLE("sorry, I don't know how to store this sort of reg in the stack");
 }
 
 void IA64InstrInfo::storeRegToAddr(MachineFunction &MF, unsigned SrcReg,
@@ -128,7 +129,7 @@
   } else if (RC == IA64::PRRegisterClass) {
     Opc = IA64::ST1;
   } else {
-    assert(0 &&
+    LLVM_UNREACHABLE(
       "sorry, I don't know how to store this sort of reg\n");
   }
 
@@ -163,7 +164,7 @@
       .addReg(IA64::r2)
       .addReg(IA64::r0);
   } else {
-    assert(0 &&
+    LLVM_UNREACHABLE(
            "sorry, I don't know how to load this sort of reg from the stack\n");
   }
 }
@@ -180,7 +181,7 @@
   } else if (RC == IA64::PRRegisterClass) {
     Opc = IA64::LD1;
   } else {
-    assert(0 &&
+    LLVM_UNREACHABLE(
       "sorry, I don't know how to load this sort of reg\n");
   }
 
diff --git a/lib/Target/IA64/IA64RegisterInfo.cpp b/lib/Target/IA64/IA64RegisterInfo.cpp
index 7ad6f51..a1a7574 100644
--- a/lib/Target/IA64/IA64RegisterInfo.cpp
+++ b/lib/Target/IA64/IA64RegisterInfo.cpp
@@ -25,6 +25,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineLocation.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetFrameInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
@@ -292,7 +293,7 @@
 }
 
 unsigned IA64RegisterInfo::getRARegister() const {
-  assert(0 && "What is the return address register");
+  LLVM_UNREACHABLE("What is the return address register");
   return 0;
 }
 
@@ -301,17 +302,17 @@
 }
 
 unsigned IA64RegisterInfo::getEHExceptionRegister() const {
-  assert(0 && "What is the exception register");
+  LLVM_UNREACHABLE("What is the exception register");
   return 0;
 }
 
 unsigned IA64RegisterInfo::getEHHandlerRegister() const {
-  assert(0 && "What is the exception handler register");
+  LLVM_UNREACHABLE("What is the exception handler register");
   return 0;
 }
 
 int IA64RegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
-  assert(0 && "What is the dwarf register number");
+  LLVM_UNREACHABLE("What is the dwarf register number");
   return -1;
 }
 
diff --git a/lib/Target/MSIL/MSILWriter.cpp b/lib/Target/MSIL/MSILWriter.cpp
index ee73c38..8429c27 100644
--- a/lib/Target/MSIL/MSILWriter.cpp
+++ b/lib/Target/MSIL/MSILWriter.cpp
@@ -19,6 +19,7 @@
 #include "llvm/TypeSymbolTable.h"
 #include "llvm/Analysis/ConstantsScanner.h"
 #include "llvm/Support/CallSite.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/InstVisitor.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Transforms/Scalar.h"
@@ -273,7 +274,7 @@
     return "modopt([mscorlib]System.Runtime.CompilerServices.CallConvStdcall) ";
   default:
     cerr << "CallingConvID = " << CallingConvID << '\n';
-    assert(0 && "Unsupported calling convention");
+    LLVM_UNREACHABLE("Unsupported calling convention");
   }
   return ""; // Not reached
 }
@@ -319,7 +320,7 @@
     return "float64 "; 
   default:
     cerr << "Type = " << *Ty << '\n';
-    assert(0 && "Invalid primitive type");
+    LLVM_UNREACHABLE("Invalid primitive type");
   }
   return ""; // Not reached
 }
@@ -347,7 +348,7 @@
     return "valuetype '"+getArrayTypeName(Ty->getTypeID(),Ty)+"' ";
   default:
     cerr << "Type = " << *Ty << '\n';
-    assert(0 && "Invalid type in getTypeName()");
+    LLVM_UNREACHABLE("Invalid type in getTypeName()");
   }
   return ""; // Not reached
 }
@@ -391,7 +392,7 @@
     return "i"+utostr(TD->getTypeAllocSize(Ty));
   default:
     cerr << "TypeID = " << Ty->getTypeID() << '\n';
-    assert(0 && "Invalid type in TypeToPostfix()");
+    LLVM_UNREACHABLE("Invalid type in TypeToPostfix()");
   }
   return ""; // Not reached
 }
@@ -406,7 +407,7 @@
     printSimpleInstruction("conv.u8");
     break;
   default:
-    assert(0 && "Module use not supporting pointer size");
+    LLVM_UNREACHABLE("Module use not supporting pointer size");
   }
 }
 
@@ -418,14 +419,14 @@
     // FIXME: Need overflow test?
     if (!isUInt32(N)) {
       cerr << "Value = " << utostr(N) << '\n';
-      assert(0 && "32-bit pointer overflowed");
+      LLVM_UNREACHABLE("32-bit pointer overflowed");
     }
     break;
   case Module::Pointer64:
     printSimpleInstruction("ldc.i8",utostr(N).c_str());
     break;
   default:
-    assert(0 && "Module use not supporting pointer size");
+    LLVM_UNREACHABLE("Module use not supporting pointer size");
   }
 }
 
@@ -461,7 +462,7 @@
     printPtrLoad(0);
   } else {
     cerr << "Constant = " << *C << '\n';
-    assert(0 && "Invalid constant value");
+    LLVM_UNREACHABLE("Invalid constant value");
   }
   Out << '\n';
 }
@@ -510,7 +511,7 @@
     break;
   default:
     cerr << "Value = " << *V << '\n';
-    assert(0 && "Invalid value location");
+    LLVM_UNREACHABLE("Invalid value location");
   }
 }
 
@@ -525,7 +526,7 @@
     break;
   default:
     cerr << "Value  = " << *V << '\n';
-    assert(0 && "Invalid value location");
+    LLVM_UNREACHABLE("Invalid value location");
   }
 }
 
@@ -680,7 +681,7 @@
     break;
   default:
     cerr << "Opcode = " << Op << '\n';
-    assert(0 && "Invalid conversion instruction");
+    LLVM_UNREACHABLE("Invalid conversion instruction");
   }
 }
 
@@ -771,7 +772,7 @@
     Name = getConvModopt(Invoke->getCallingConv());
   else {
     cerr << "Instruction = " << Inst->getName() << '\n';
-    assert(0 && "Need \"Invoke\" or \"Call\" instruction only");
+    LLVM_UNREACHABLE("Need \"Invoke\" or \"Call\" instruction only");
   }
   if (const Function* F = dyn_cast<Function>(FnVal)) {
     // Direct call.
@@ -819,7 +820,7 @@
     break;        
   default:
     cerr << "Intrinsic ID = " << Inst->getIntrinsicID() << '\n';
-    assert(0 && "Invalid intrinsic function");
+    LLVM_UNREACHABLE("Invalid intrinsic function");
   }
 }
 
@@ -882,7 +883,7 @@
     break;
   default:
     cerr << "Predicate = " << Predicate << '\n';
-    assert(0 && "Invalid icmp predicate");
+    LLVM_UNREACHABLE("Invalid icmp predicate");
   }
 }
 
@@ -976,7 +977,7 @@
     printSimpleInstruction("or");
     break;
   default:
-    assert(0 && "Illegal FCmp predicate");
+    LLVM_UNREACHABLE("Illegal FCmp predicate");
   }
 }
 
@@ -1169,10 +1170,10 @@
     printAllocaInstruction(cast<AllocaInst>(Inst));
     break;
   case Instruction::Malloc:
-    assert(0 && "LowerAllocationsPass used");
+    LLVM_UNREACHABLE("LowerAllocationsPass used");
     break;
   case Instruction::Free:
-    assert(0 && "LowerAllocationsPass used");
+    LLVM_UNREACHABLE("LowerAllocationsPass used");
     break;
   case Instruction::Unreachable:
     printSimpleInstruction("ldstr", "\"Unreachable instruction\"");
@@ -1185,7 +1186,7 @@
     break;
   default:
     cerr << "Instruction = " << Inst->getName() << '\n';
-    assert(0 && "Unsupported instruction");
+    LLVM_UNREACHABLE("Unsupported instruction");
   }
 }
 
@@ -1373,7 +1374,7 @@
     break;
   default:
     cerr << "Expression = " << *CE << "\n";
-    assert(0 && "Invalid constant expression");
+    LLVM_UNREACHABLE("Invalid constant expression");
   }
 }
 
@@ -1407,7 +1408,7 @@
         printSimpleInstruction(postfix.c_str());
       } else {
         cerr << "Constant = " << *I->constant << '\n';
-        assert(0 && "Invalid static initializer");
+        LLVM_UNREACHABLE("Invalid static initializer");
       }
     }
   }
@@ -1471,7 +1472,7 @@
     return N;
   default:
     cerr << "Bits = " << N << '\n';
-    assert(0 && "Unsupported integer width");
+    LLVM_UNREACHABLE("Unsupported integer width");
   }
   return 0; // Not reached
 }
@@ -1528,12 +1529,12 @@
       // Null pointer initialization
       if (TySize==4) Out << "int32 (0)";
       else if (TySize==8) Out << "int64 (0)";
-      else assert(0 && "Invalid pointer size");
+      else LLVM_UNREACHABLE("Invalid pointer size");
     }
     break;
   default:
     cerr << "TypeID = " << Ty->getTypeID() << '\n';
-    assert(0 && "Invalid type in printStaticConstant()");
+    LLVM_UNREACHABLE("Invalid type in printStaticConstant()");
   }
   // Increase offset.
   Offset += TySize;
@@ -1556,7 +1557,7 @@
     break;
   default:
     cerr << "Type = " << *C << "\n";
-    assert(0 && "Invalid constant type");
+    LLVM_UNREACHABLE("Invalid constant type");
   }
   // Print initializer
   std::string label = Name;
diff --git a/lib/Target/MSP430/MSP430AsmPrinter.cpp b/lib/Target/MSP430/MSP430AsmPrinter.cpp
index b1fa3f0..0f711ab 100644
--- a/lib/Target/MSP430/MSP430AsmPrinter.cpp
+++ b/lib/Target/MSP430/MSP430AsmPrinter.cpp
@@ -31,6 +31,7 @@
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Mangler.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/ErrorHandling.h"
 
 using namespace llvm;
 
@@ -99,7 +100,7 @@
   EmitAlignment(FnAlign, F);
 
   switch (F->getLinkage()) {
-  default: assert(0 && "Unknown linkage type!");
+  default: LLVM_UNREACHABLE("Unknown linkage type!");
   case Function::InternalLinkage:  // Symbols default to internal.
   case Function::PrivateLinkage:
     break;
@@ -161,7 +162,7 @@
   if (printInstruction(MI))
     return;
 
-  assert(0 && "Should not happen");
+  LLVM_UNREACHABLE("Should not happen");
 }
 
 void MSP430AsmPrinter::printOperand(const MachineInstr *MI, int OpNum,
@@ -206,7 +207,7 @@
     return;
   }
   default:
-    assert(0 && "Not implemented yet!");
+    LLVM_UNREACHABLE("Not implemented yet!");
   }
 }
 
@@ -230,7 +231,7 @@
       printOperand(MI, OpNum);
     }
   } else
-    assert(0 && "Unsupported memory operand");
+    LLVM_UNREACHABLE("Unsupported memory operand");
 }
 
 void MSP430AsmPrinter::printCCOperand(const MachineInstr *MI, int OpNum) {
@@ -238,7 +239,7 @@
 
   switch (CC) {
   default:
-   assert(0 && "Unsupported CC code");
+   LLVM_UNREACHABLE("Unsupported CC code");
    break;
   case MSP430::COND_E:
    O << "eq";
diff --git a/lib/Target/MSP430/MSP430ISelLowering.cpp b/lib/Target/MSP430/MSP430ISelLowering.cpp
index 1522e50..69d9cae 100644
--- a/lib/Target/MSP430/MSP430ISelLowering.cpp
+++ b/lib/Target/MSP430/MSP430ISelLowering.cpp
@@ -123,7 +123,7 @@
   case ISD::SELECT_CC:        return LowerSELECT_CC(Op, DAG);
   case ISD::SIGN_EXTEND:      return LowerSIGN_EXTEND(Op, DAG);
   default:
-    assert(0 && "unimplemented operand");
+    LLVM_UNREACHABLE("unimplemented operand");
     return SDValue();
   }
 }
@@ -144,7 +144,7 @@
   unsigned CC = cast<ConstantSDNode>(Op.getOperand(1))->getZExtValue();
   switch (CC) {
   default:
-    assert(0 && "Unsupported calling convention");
+    LLVM_UNREACHABLE("Unsupported calling convention");
   case CallingConv::C:
   case CallingConv::Fast:
     return LowerCCCArguments(Op, DAG);
@@ -156,7 +156,7 @@
   unsigned CallingConv = TheCall->getCallingConv();
   switch (CallingConv) {
   default:
-    assert(0 && "Unsupported calling convention");
+    LLVM_UNREACHABLE("Unsupported calling convention");
   case CallingConv::Fast:
   case CallingConv::C:
     return LowerCCCCallTo(Op, DAG, CallingConv);
@@ -331,7 +331,7 @@
 
     // Promote the value if needed.
     switch (VA.getLocInfo()) {
-      default: assert(0 && "Unknown loc info!");
+      default: LLVM_UNREACHABLE("Unknown loc info!");
       case CCValAssign::Full: break;
       case CCValAssign::SExt:
         Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
@@ -516,7 +516,7 @@
   // FIXME: Handle jump negative someday
   TargetCC = MSP430::COND_INVALID;
   switch (CC) {
-  default: assert(0 && "Invalid integer condition!");
+  default: LLVM_UNREACHABLE("Invalid integer condition!");
   case ISD::SETEQ:
     TargetCC = MSP430::COND_E;  // aka COND_Z
     break;
diff --git a/lib/Target/MSP430/MSP430InstrInfo.cpp b/lib/Target/MSP430/MSP430InstrInfo.cpp
index 91112c3..8dc71df 100644
--- a/lib/Target/MSP430/MSP430InstrInfo.cpp
+++ b/lib/Target/MSP430/MSP430InstrInfo.cpp
@@ -21,6 +21,7 @@
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/PseudoSourceValue.h"
+#include "llvm/Support/ErrorHandling.h"
 
 using namespace llvm;
 
@@ -44,7 +45,7 @@
       .addFrameIndex(FrameIdx).addImm(0)
       .addReg(SrcReg, getKillRegState(isKill));
   else
-    assert(0 && "Cannot store this register to stack slot!");
+    LLVM_UNREACHABLE("Cannot store this register to stack slot!");
 }
 
 void MSP430InstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
@@ -61,7 +62,7 @@
     BuildMI(MBB, MI, DL, get(MSP430::MOV8rm))
       .addReg(DestReg).addFrameIndex(FrameIdx).addImm(0);
   else
-    assert(0 && "Cannot store this register to stack slot!");
+    LLVM_UNREACHABLE("Cannot store this register to stack slot!");
 }
 
 bool MSP430InstrInfo::copyRegToReg(MachineBasicBlock &MBB,
@@ -171,7 +172,7 @@
 
   // Conditional branch.
   unsigned Count = 0;
-  assert(0 && "Implement conditional branches!");
+  LLVM_UNREACHABLE("Implement conditional branches!");
 
   return Count;
 }
diff --git a/lib/Target/MSP430/MSP430RegisterInfo.cpp b/lib/Target/MSP430/MSP430RegisterInfo.cpp
index d40bac7..2c96f85 100644
--- a/lib/Target/MSP430/MSP430RegisterInfo.cpp
+++ b/lib/Target/MSP430/MSP430RegisterInfo.cpp
@@ -23,6 +23,7 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/ADT/BitVector.h"
+#include "llvm/Support/ErrorHandling.h"
 
 using namespace llvm;
 
@@ -291,7 +292,7 @@
   switch (RetOpcode) {
   case MSP430::RET: break;  // These are ok
   default:
-    assert(0 && "Can only insert epilog into returning blocks");
+    LLVM_UNREACHABLE("Can only insert epilog into returning blocks");
   }
 
   // Get the number of bytes to allocate from the FrameInfo
@@ -327,7 +328,7 @@
   //  mergeSPUpdatesUp(MBB, MBBI, StackPtr, &NumBytes);
 
   if (MFI->hasVarSizedObjects()) {
-    assert(0 && "Not implemented yet!");
+    LLVM_UNREACHABLE("Not implemented yet!");
   } else {
     // adjust stack pointer back: SPW += numbytes
     if (NumBytes) {
@@ -349,7 +350,7 @@
 }
 
 int MSP430RegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
-  assert(0 && "Not implemented yet!");
+  LLVM_UNREACHABLE("Not implemented yet!");
   return 0;
 }
 
diff --git a/lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp b/lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp
index 837e389..17c7640 100644
--- a/lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp
+++ b/lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp
@@ -216,7 +216,7 @@
     default: break;
   }
 
-  assert(0 && "Unknown Mips ABI");
+  LLVM_UNREACHABLE( "Unknown Mips ABI");
   return NULL;
 }  
 
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index f132d2d..f3fa179 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -31,6 +31,7 @@
 #include "llvm/CodeGen/SelectionDAGISel.h"
 #include "llvm/CodeGen/ValueTypes.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
 const char *MipsTargetLowering::
@@ -247,7 +248,7 @@
 static unsigned FPBranchCodeToOpc(Mips::FPBranchCode BC) {
   switch(BC) {
     default:
-      assert(0 && "Unknown branch code");
+      LLVM_UNREACHABLE("Unknown branch code");
     case Mips::BRANCH_T  : return Mips::BC1T;
     case Mips::BRANCH_F  : return Mips::BC1F;
     case Mips::BRANCH_TL : return Mips::BC1TL;
@@ -257,7 +258,7 @@
 
 static Mips::CondCode FPCondCCodeToFCC(ISD::CondCode CC) {
   switch (CC) {
-  default: assert(0 && "Unknown fp condition code!");
+  default: LLVM_UNREACHABLE("Unknown fp condition code!");
   case ISD::SETEQ:  
   case ISD::SETOEQ: return Mips::FCOND_EQ;
   case ISD::SETUNE: return Mips::FCOND_OGL;
@@ -541,14 +542,14 @@
     return DAG.getNode(ISD::ADD, dl, MVT::i32, ResNode, Lo);
   }
 
-  assert(0 && "Dont know how to handle GlobalAddress");
+  LLVM_UNREACHABLE("Dont know how to handle GlobalAddress");
   return SDValue(0,0);
 }
 
 SDValue MipsTargetLowering::
 LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG)
 {
-  assert(0 && "TLS not implemented for MIPS.");
+  LLVM_UNREACHABLE("TLS not implemented for MIPS.");
   return SDValue(); // Not reached
 }
 
@@ -752,7 +753,7 @@
 
     // Promote the value if needed.
     switch (VA.getLocInfo()) {
-    default: assert(0 && "Unknown loc info!");
+    default: LLVM_UNREACHABLE("Unknown loc info!");
     case CCValAssign::Full: 
       if (Subtarget->isABI_O32() && VA.isRegLoc()) {
         if (VA.getValVT() == MVT::f32 && VA.getLocVT() == MVT::i32)
@@ -977,7 +978,7 @@
         if (!Subtarget->isSingleFloat()) 
           RC = Mips::AFGR64RegisterClass;
       } else  
-        assert(0 && "RegVT not supported by FORMAL_ARGUMENTS Lowering");
+        LLVM_UNREACHABLE("RegVT not supported by FORMAL_ARGUMENTS Lowering");
 
       // Transform the arguments stored on 
       // physical registers into virtual ones
@@ -1139,7 +1140,7 @@
     unsigned Reg = MipsFI->getSRetReturnReg();
 
     if (!Reg) 
-      assert(0 && "sret virtual register not created in the entry block");
+      LLVM_UNREACHABLE("sret virtual register not created in the entry block");
     SDValue Val = DAG.getCopyFromReg(Chain, dl, Reg, getPointerTy());
 
     Chain = DAG.getCopyToReg(Chain, dl, Mips::V0, Val, Flag);
diff --git a/lib/Target/Mips/MipsInstrInfo.cpp b/lib/Target/Mips/MipsInstrInfo.cpp
index e16fd8e..1150765 100644
--- a/lib/Target/Mips/MipsInstrInfo.cpp
+++ b/lib/Target/Mips/MipsInstrInfo.cpp
@@ -17,6 +17,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "MipsGenInstrInfo.inc"
 
 using namespace llvm;
@@ -372,7 +373,7 @@
 unsigned Mips::GetCondBranchFromCond(Mips::CondCode CC) 
 {
   switch (CC) {
-  default: assert(0 && "Illegal condition code!");
+  default: LLVM_UNREACHABLE("Illegal condition code!");
   case Mips::COND_E   : return Mips::BEQ;
   case Mips::COND_NE  : return Mips::BNE;
   case Mips::COND_GZ  : return Mips::BGTZ;
@@ -421,7 +422,7 @@
 Mips::CondCode Mips::GetOppositeBranchCondition(Mips::CondCode CC) 
 {
   switch (CC) {
-  default: assert(0 && "Illegal condition code!");
+  default: LLVM_UNREACHABLE("Illegal condition code!");
   case Mips::COND_E   : return Mips::COND_NE;
   case Mips::COND_NE  : return Mips::COND_E;
   case Mips::COND_GZ  : return Mips::COND_LEZ;
diff --git a/lib/Target/Mips/MipsInstrInfo.h b/lib/Target/Mips/MipsInstrInfo.h
index 6655c67..9c47d8e 100644
--- a/lib/Target/Mips/MipsInstrInfo.h
+++ b/lib/Target/Mips/MipsInstrInfo.h
@@ -15,6 +15,7 @@
 #define MIPSINSTRUCTIONINFO_H
 
 #include "Mips.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "MipsRegisterInfo.h"
 
@@ -92,7 +93,7 @@
   inline static const char *MipsFCCToString(Mips::CondCode CC) 
   {
     switch (CC) {
-      default: assert(0 && "Unknown condition code");
+      default: LLVM_UNREACHABLE("Unknown condition code");
       case FCOND_F:
       case FCOND_T:   return "f";
       case FCOND_UN:
diff --git a/lib/Target/Mips/MipsRegisterInfo.cpp b/lib/Target/Mips/MipsRegisterInfo.cpp
index 579d4db..816d7c7 100644
--- a/lib/Target/Mips/MipsRegisterInfo.cpp
+++ b/lib/Target/Mips/MipsRegisterInfo.cpp
@@ -31,6 +31,7 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/STLExtras.h"
 
@@ -79,7 +80,7 @@
     case Mips::SP   : case Mips::F29: return 29;
     case Mips::FP   : case Mips::F30: case Mips::D15: return 30;
     case Mips::RA   : case Mips::F31: return 31;
-    default: assert(0 && "Unknown register number!");
+    default: LLVM_UNREACHABLE("Unknown register number!");
   }    
   return 0; // Not reached
 }
@@ -515,19 +516,19 @@
 
 unsigned MipsRegisterInfo::
 getEHExceptionRegister() const {
-  assert(0 && "What is the exception register");
+  LLVM_UNREACHABLE("What is the exception register");
   return 0;
 }
 
 unsigned MipsRegisterInfo::
 getEHHandlerRegister() const {
-  assert(0 && "What is the exception handler register");
+  LLVM_UNREACHABLE("What is the exception handler register");
   return 0;
 }
 
 int MipsRegisterInfo::
 getDwarfRegNum(unsigned RegNum, bool isEH) const {
-  assert(0 && "What is the dwarf register number");
+  LLVM_UNREACHABLE("What is the dwarf register number");
   return -1;
 }
 
diff --git a/lib/Target/PIC16/PIC16.h b/lib/Target/PIC16/PIC16.h
index 0a71b13..6af4664 100644
--- a/lib/Target/PIC16/PIC16.h
+++ b/lib/Target/PIC16/PIC16.h
@@ -15,6 +15,7 @@
 #ifndef LLVM_TARGET_PIC16_H
 #define LLVM_TARGET_PIC16_H
 
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetMachine.h"
 #include <iosfwd>
 #include <cassert>
@@ -307,7 +308,7 @@
 
   inline static const char *PIC16CondCodeToString(PIC16CC::CondCodes CC) {
     switch (CC) {
-    default: assert(0 && "Unknown condition code");
+    default: LLVM_UNREACHABLE("Unknown condition code");
     case PIC16CC::NE:  return "ne";
     case PIC16CC::EQ:   return "eq";
     case PIC16CC::LT:   return "lt";
@@ -323,7 +324,7 @@
 
   inline static bool isSignedComparison(PIC16CC::CondCodes CC) {
     switch (CC) {
-    default: assert(0 && "Unknown condition code");
+    default: LLVM_UNREACHABLE("Unknown condition code");
     case PIC16CC::NE:  
     case PIC16CC::EQ: 
     case PIC16CC::LT:
diff --git a/lib/Target/PIC16/PIC16AsmPrinter.cpp b/lib/Target/PIC16/PIC16AsmPrinter.cpp
index 6466ad6..d80476c 100644
--- a/lib/Target/PIC16/PIC16AsmPrinter.cpp
+++ b/lib/Target/PIC16/PIC16AsmPrinter.cpp
@@ -21,6 +21,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/Mangler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/CodeGen/DwarfWriter.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 
@@ -127,8 +128,8 @@
       if (TargetRegisterInfo::isPhysicalRegister(MO.getReg()))
         O << TM.getRegisterInfo()->get(MO.getReg()).AsmName;
       else
-        assert(0 && "not implemented");
-        return;
+        LLVM_UNREACHABLE("not implemented");
+      return;
 
     case MachineOperand::MO_Immediate:
       O << (int)MO.getImm();
@@ -154,7 +155,7 @@
       return;
 
     default:
-      assert(0 && " Operand type not supported.");
+      LLVM_UNREACHABLE(" Operand type not supported.");
   }
 }
 
diff --git a/lib/Target/PIC16/PIC16ISelLowering.cpp b/lib/Target/PIC16/PIC16ISelLowering.cpp
index 02547b5..c8c353f 100644
--- a/lib/Target/PIC16/PIC16ISelLowering.cpp
+++ b/lib/Target/PIC16/PIC16ISelLowering.cpp
@@ -1697,7 +1697,7 @@
 
 static PIC16CC::CondCodes IntCCToPIC16CC(ISD::CondCode CC) {
   switch (CC) {
-  default: assert(0 && "Unknown condition code!");
+  default: LLVM_UNREACHABLE("Unknown condition code!");
   case ISD::SETNE:  return PIC16CC::NE;
   case ISD::SETEQ:  return PIC16CC::EQ;
   case ISD::SETGT:  return PIC16CC::GT;
diff --git a/lib/Target/PIC16/PIC16InstrInfo.cpp b/lib/Target/PIC16/PIC16InstrInfo.cpp
index 8418423..dad0266 100644
--- a/lib/Target/PIC16/PIC16InstrInfo.cpp
+++ b/lib/Target/PIC16/PIC16InstrInfo.cpp
@@ -20,6 +20,7 @@
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <cstdio>
 
 
@@ -104,7 +105,7 @@
       .addImm(1); // Emit banksel for it.
   }
   else
-    assert(0 && "Can't store this register to stack slot");
+    LLVM_UNREACHABLE("Can't store this register to stack slot");
 }
 
 void PIC16InstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB, 
@@ -144,7 +145,7 @@
       .addImm(1); // Emit banksel for it.
   }
   else
-    assert(0 && "Can't load this register from stack slot");
+    LLVM_UNREACHABLE("Can't load this register from stack slot");
 }
 
 bool PIC16InstrInfo::copyRegToReg (MachineBasicBlock &MBB,
diff --git a/lib/Target/PIC16/PIC16RegisterInfo.cpp b/lib/Target/PIC16/PIC16RegisterInfo.cpp
index eb758d8..bb4f278 100644
--- a/lib/Target/PIC16/PIC16RegisterInfo.cpp
+++ b/lib/Target/PIC16/PIC16RegisterInfo.cpp
@@ -16,7 +16,7 @@
 #include "PIC16.h"
 #include "PIC16RegisterInfo.h"
 #include "llvm/ADT/BitVector.h"
-
+#include "llvm/Support/ErrorHandling.h"
 
 using namespace llvm;
 
@@ -65,17 +65,17 @@
 
 int PIC16RegisterInfo::
 getDwarfRegNum(unsigned RegNum, bool isEH) const {
-  assert(0 && "Not keeping track of debug information yet!!");
+  LLVM_UNREACHABLE("Not keeping track of debug information yet!!");
   return -1;
 }
 
 unsigned PIC16RegisterInfo::getFrameRegister(MachineFunction &MF) const {
-  assert(0 && "PIC16 Does not have any frame register");
+  LLVM_UNREACHABLE("PIC16 Does not have any frame register");
   return 0;
 }
 
 unsigned PIC16RegisterInfo::getRARegister() const {
-  assert(0 && "PIC16 Does not have any return address register");
+  LLVM_UNREACHABLE("PIC16 Does not have any return address register");
   return 0;
 }
 
diff --git a/lib/Target/PowerPC/AsmPrinter/PPCAsmPrinter.cpp b/lib/Target/PowerPC/AsmPrinter/PPCAsmPrinter.cpp
index 373a2ef..fd7cbff 100644
--- a/lib/Target/PowerPC/AsmPrinter/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/AsmPrinter/PPCAsmPrinter.cpp
@@ -571,7 +571,7 @@
   SwitchToSection(TAI->SectionForGlobal(F));
 
   switch (F->getLinkage()) {
-  default: assert(0 && "Unknown linkage type!");
+  default: LLVM_UNREACHABLE( "Unknown linkage type!");
   case Function::PrivateLinkage:
   case Function::InternalLinkage:  // Symbols default to internal.
     break;
@@ -748,7 +748,7 @@
   SwitchToSection(TAI->SectionForGlobal(F));
 
   switch (F->getLinkage()) {
-  default: assert(0 && "Unknown linkage type!");
+  default: LLVM_UNREACHABLE( "Unknown linkage type!");
   case Function::PrivateLinkage:
   case Function::InternalLinkage:  // Symbols default to internal.
     break;
diff --git a/lib/Target/PowerPC/PPCCodeEmitter.cpp b/lib/Target/PowerPC/PPCCodeEmitter.cpp
index c191f65..4943e5c 100644
--- a/lib/Target/PowerPC/PPCCodeEmitter.cpp
+++ b/lib/Target/PowerPC/PPCCodeEmitter.cpp
@@ -181,7 +181,7 @@
         assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
       }
       switch (MI.getOpcode()) {
-      default: MI.dump(); assert(0 && "Unknown instruction for relocation!");
+      default: MI.dump(); LLVM_UNREACHABLE("Unknown instruction for relocation!");
       case PPC::LIS:
       case PPC::LIS8:
       case PPC::ADDIS:
diff --git a/lib/Target/PowerPC/PPCHazardRecognizers.cpp b/lib/Target/PowerPC/PPCHazardRecognizers.cpp
index ec3e757..244d395 100644
--- a/lib/Target/PowerPC/PPCHazardRecognizers.cpp
+++ b/lib/Target/PowerPC/PPCHazardRecognizers.cpp
@@ -17,6 +17,7 @@
 #include "PPCInstrInfo.h"
 #include "llvm/CodeGen/ScheduleDAG.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
 //===----------------------------------------------------------------------===//
@@ -141,7 +142,7 @@
     return Hazard;
       
   switch (InstrType) {
-  default: assert(0 && "Unknown instruction type!");
+  default: LLVM_UNREACHABLE("Unknown instruction type!");
   case PPCII::PPC970_FXU:
   case PPCII::PPC970_LSU:
   case PPCII::PPC970_FPU:
@@ -167,7 +168,7 @@
   if (isLoad && NumStores) {
     unsigned LoadSize;
     switch (Opcode) {
-    default: assert(0 && "Unknown load!");
+    default: LLVM_UNREACHABLE("Unknown load!");
     case PPC::LBZ:   case PPC::LBZU:
     case PPC::LBZX:
     case PPC::LBZ8:  case PPC::LBZU8:
@@ -235,7 +236,7 @@
   if (isStore) {
     unsigned ThisStoreSize;
     switch (Opcode) {
-    default: assert(0 && "Unknown store instruction!");
+    default: LLVM_UNREACHABLE("Unknown store instruction!");
     case PPC::STB:    case PPC::STB8:
     case PPC::STBU:   case PPC::STBU8:
     case PPC::STBX:   case PPC::STBX8:
diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 398a1fe..b17e54d 100644
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -653,7 +653,7 @@
   case ISD::SETOGE: 
   case ISD::SETOLE: 
   case ISD::SETONE:
-    assert(0 && "Invalid branch code: should be expanded by legalize");
+    LLVM_UNREACHABLE("Invalid branch code: should be expanded by legalize");
   // These are invalid for floating point.  Assume integer.
   case ISD::SETULT: return 0;
   case ISD::SETUGT: return 1;
@@ -941,7 +941,7 @@
         // Handle PPC32 integer and normal FP loads.
         assert((!isSExt || LoadedVT == MVT::i16) && "Invalid sext update load");
         switch (LoadedVT.getSimpleVT()) {
-          default: assert(0 && "Invalid PPC load type!");
+          default: LLVM_UNREACHABLE("Invalid PPC load type!");
           case MVT::f64: Opcode = PPC::LFDU; break;
           case MVT::f32: Opcode = PPC::LFSU; break;
           case MVT::i32: Opcode = PPC::LWZU; break;
@@ -953,7 +953,7 @@
         assert(LD->getValueType(0) == MVT::i64 && "Unknown load result type!");
         assert((!isSExt || LoadedVT == MVT::i16) && "Invalid sext update load");
         switch (LoadedVT.getSimpleVT()) {
-          default: assert(0 && "Invalid PPC load type!");
+          default: LLVM_UNREACHABLE("Invalid PPC load type!");
           case MVT::i64: Opcode = PPC::LDU; break;
           case MVT::i32: Opcode = PPC::LWZU8; break;
           case MVT::i16: Opcode = isSExt ? PPC::LHAU8 : PPC::LHZU8; break;
@@ -970,7 +970,7 @@
                                    PPCLowering.getPointerTy(),
                                    MVT::Other, Ops, 3);
     } else {
-      assert(0 && "R+R preindex loads not supported yet!");
+      LLVM_UNREACHABLE("R+R preindex loads not supported yet!");
     }
   }
     
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index abd428c..842361f 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -1156,7 +1156,7 @@
 
 SDValue PPCTargetLowering::LowerGlobalTLSAddress(SDValue Op,
                                                    SelectionDAG &DAG) {
-  assert(0 && "TLS not implemented for PPC.");
+  LLVM_UNREACHABLE("TLS not implemented for PPC.");
   return SDValue(); // Not reached
 }
 
@@ -1251,7 +1251,7 @@
                               unsigned VarArgsNumFPR,
                               const PPCSubtarget &Subtarget) {
 
-  assert(0 && "VAARG not yet implemented for the SVR4 ABI!");
+  LLVM_UNREACHABLE("VAARG not yet implemented for the SVR4 ABI!");
   return SDValue(); // Not reached
 }
 
@@ -1544,7 +1544,7 @@
       
       switch (ValVT.getSimpleVT()) {
         default:
-          assert(0 && "ValVT not supported by FORMAL_ARGUMENTS Lowering");
+          LLVM_UNREACHABLE("ValVT not supported by FORMAL_ARGUMENTS Lowering");
         case MVT::i32:
           RC = PPC::GPRCRegisterClass;
           break;
@@ -1785,7 +1785,7 @@
       }
 
       switch(ObjectVT.getSimpleVT()) {
-      default: assert(0 && "Unhandled argument type!");
+      default: LLVM_UNREACHABLE("Unhandled argument type!");
       case MVT::i32:
       case MVT::f32:
         VecArgOffset += isPPC64 ? 8 : 4;
@@ -1892,7 +1892,7 @@
     }
 
     switch (ObjectVT.getSimpleVT()) {
-    default: assert(0 && "Unhandled argument type!");
+    default: LLVM_UNREACHABLE("Unhandled argument type!");
     case MVT::i32:
       if (!isPPC64) {
         if (GPR_idx != Num_GPR_Regs) {
@@ -2902,7 +2902,7 @@
     }
 
     switch (Arg.getValueType().getSimpleVT()) {
-    default: assert(0 && "Unexpected ValueType for argument!");
+    default: LLVM_UNREACHABLE("Unexpected ValueType for argument!");
     case MVT::i32:
     case MVT::i64:
       if (GPR_idx != NumGPRs) {
@@ -3309,7 +3309,7 @@
 
   SDValue Tmp;
   switch (Op.getValueType().getSimpleVT()) {
-  default: assert(0 && "Unhandled FP_TO_INT type in custom expander!");
+  default: LLVM_UNREACHABLE("Unhandled FP_TO_INT type in custom expander!");
   case MVT::i32:
     Tmp = DAG.getNode(Op.getOpcode()==ISD::FP_TO_SINT ? PPCISD::FCTIWZ :
                                                          PPCISD::FCTIDZ, 
@@ -3795,7 +3795,7 @@
 
   int ShufIdxs[16];
   switch (OpNum) {
-  default: assert(0 && "Unknown i32 permute!");
+  default: LLVM_UNREACHABLE("Unknown i32 permute!");
   case OP_VMRGHW:
     ShufIdxs[ 0] =  0; ShufIdxs[ 1] =  1; ShufIdxs[ 2] =  2; ShufIdxs[ 3] =  3;
     ShufIdxs[ 4] = 16; ShufIdxs[ 5] = 17; ShufIdxs[ 6] = 18; ShufIdxs[ 7] = 19;
@@ -4155,7 +4155,7 @@
 ///
 SDValue PPCTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) {
   switch (Op.getOpcode()) {
-  default: assert(0 && "Wasn't expecting to be able to lower this!");
+  default: LLVM_UNREACHABLE("Wasn't expecting to be able to lower this!");
   case ISD::ConstantPool:       return LowerConstantPool(Op, DAG);
   case ISD::GlobalAddress:      return LowerGlobalAddress(Op, DAG);
   case ISD::GlobalTLSAddress:   return LowerGlobalTLSAddress(Op, DAG);
@@ -4817,7 +4817,7 @@
     BB = exitMBB;
     BuildMI(BB, dl, TII->get(PPC::SRW),dest).addReg(TmpReg).addReg(ShiftReg);
   } else {
-    assert(0 && "Unexpected instr type to insert");
+    LLVM_UNREACHABLE("Unexpected instr type to insert");
   }
 
   F->DeleteMachineInstr(MI);   // The pseudo instruction is gone now.
@@ -5192,7 +5192,7 @@
     if (!CST) return; // Must be an immediate to match.
     unsigned Value = CST->getZExtValue();
     switch (Letter) {
-    default: assert(0 && "Unknown constraint letter!");
+    default: LLVM_UNREACHABLE("Unknown constraint letter!");
     case 'I':  // "I" is a signed 16-bit constant.
       if ((short)Value == (int)Value)
         Result = DAG.getTargetConstant(Value, Op.getValueType());
diff --git a/lib/Target/PowerPC/PPCJITInfo.cpp b/lib/Target/PowerPC/PPCJITInfo.cpp
index 25f3785..91deca1 100644
--- a/lib/Target/PowerPC/PPCJITInfo.cpp
+++ b/lib/Target/PowerPC/PPCJITInfo.cpp
@@ -383,7 +383,7 @@
     unsigned *RelocPos = (unsigned*)Function + MR->getMachineCodeOffset()/4;
     intptr_t ResultPtr = (intptr_t)MR->getResultPointer();
     switch ((PPC::RelocationType)MR->getRelocationType()) {
-    default: assert(0 && "Unknown relocation type!");
+    default: LLVM_UNREACHABLE("Unknown relocation type!");
     case PPC::reloc_pcrel_bx:
       // PC-relative relocation for b and bl instructions.
       ResultPtr = (ResultPtr-(intptr_t)RelocPos) >> 2;
diff --git a/lib/Target/PowerPC/PPCMachOWriterInfo.cpp b/lib/Target/PowerPC/PPCMachOWriterInfo.cpp
index 3bfa6d7..9e57bd9 100644
--- a/lib/Target/PowerPC/PPCMachOWriterInfo.cpp
+++ b/lib/Target/PowerPC/PPCMachOWriterInfo.cpp
@@ -16,6 +16,7 @@
 #include "PPCTargetMachine.h"
 #include "llvm/CodeGen/MachORelocation.h"
 #include "llvm/Support/OutputBuffer.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <cstdio>
 using namespace llvm;
 
@@ -46,9 +47,9 @@
     Addr = (uintptr_t)MR.getResultPointer() + ToAddr;
 
   switch ((PPC::RelocationType)MR.getRelocationType()) {
-  default: assert(0 && "Unknown PPC relocation type!");
+  default: LLVM_UNREACHABLE("Unknown PPC relocation type!");
   case PPC::reloc_absolute_low_ix:
-    assert(0 && "Unhandled PPC relocation type!");
+    LLVM_UNREACHABLE("Unhandled PPC relocation type!");
     break;
   case PPC::reloc_vanilla:
     {
diff --git a/lib/Target/PowerPC/PPCPredicates.cpp b/lib/Target/PowerPC/PPCPredicates.cpp
index 08a2812..bb9e166 100644
--- a/lib/Target/PowerPC/PPCPredicates.cpp
+++ b/lib/Target/PowerPC/PPCPredicates.cpp
@@ -12,12 +12,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "PPCPredicates.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <cassert>
 using namespace llvm;
 
 PPC::Predicate PPC::InvertPredicate(PPC::Predicate Opcode) {
   switch (Opcode) {
-  default: assert(0 && "Unknown PPC branch opcode!");
+  default: LLVM_UNREACHABLE("Unknown PPC branch opcode!");
   case PPC::PRED_EQ: return PPC::PRED_NE;
   case PPC::PRED_NE: return PPC::PRED_EQ;
   case PPC::PRED_LT: return PPC::PRED_GE;
diff --git a/lib/Target/PowerPC/PPCRegisterInfo.cpp b/lib/Target/PowerPC/PPCRegisterInfo.cpp
index 26d08d0..6f807fe 100644
--- a/lib/Target/PowerPC/PPCRegisterInfo.cpp
+++ b/lib/Target/PowerPC/PPCRegisterInfo.cpp
@@ -1065,7 +1065,7 @@
         MinVR = Reg;
       }
     } else {
-      assert(0 && "Unknown RegisterClass!");
+      LLVM_UNREACHABLE("Unknown RegisterClass!");
     }
   }
 
diff --git a/lib/Target/Sparc/FPMover.cpp b/lib/Target/Sparc/FPMover.cpp
index f72a4c4..0f251de 100644
--- a/lib/Target/Sparc/FPMover.cpp
+++ b/lib/Target/Sparc/FPMover.cpp
@@ -20,6 +20,7 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
 STATISTIC(NumFpDs , "Number of instructions translated");
@@ -75,7 +76,7 @@
       OddReg = OddHalvesOfPairs[i];
       return;
     }
-  assert(0 && "Can't find reg");
+  LLVM_UNREACHABLE("Can't find reg");
 }
 
 /// runOnMachineBasicBlock - Fixup FpMOVD instructions in this MBB.
@@ -108,7 +109,7 @@
       else if (MI->getOpcode() == SP::FpABSD)
         MI->setDesc(TII->get(SP::FABSS));
       else
-        assert(0 && "Unknown opcode!");
+        LLVM_UNREACHABLE("Unknown opcode!");
         
       MI->getOperand(0).setReg(EvenDestReg);
       MI->getOperand(1).setReg(EvenSrcReg);
diff --git a/lib/Target/Sparc/Sparc.h b/lib/Target/Sparc/Sparc.h
index c7d0ca8..539e50a 100644
--- a/lib/Target/Sparc/Sparc.h
+++ b/lib/Target/Sparc/Sparc.h
@@ -15,6 +15,7 @@
 #ifndef TARGET_SPARC_H
 #define TARGET_SPARC_H
 
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetMachine.h"
 #include <cassert>
 
@@ -83,7 +84,7 @@
   
   inline static const char *SPARCCondCodeToString(SPCC::CondCodes CC) {
     switch (CC) {
-    default: assert(0 && "Unknown condition code");
+    default: LLVM_UNREACHABLE("Unknown condition code");
     case SPCC::ICC_NE:  return "ne";
     case SPCC::ICC_E:   return "e";
     case SPCC::ICC_G:   return "g";
diff --git a/lib/Target/Sparc/SparcISelLowering.cpp b/lib/Target/Sparc/SparcISelLowering.cpp
index 850d8e3..4f5060e 100644
--- a/lib/Target/Sparc/SparcISelLowering.cpp
+++ b/lib/Target/Sparc/SparcISelLowering.cpp
@@ -22,6 +22,7 @@
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/ADT/VectorExtras.h"
+#include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
 
@@ -98,7 +99,7 @@
     MVT ObjectVT = getValueType(I->getType());
 
     switch (ObjectVT.getSimpleVT()) {
-    default: assert(0 && "Unhandled argument type!");
+    default: LLVM_UNREACHABLE("Unhandled argument type!");
     case MVT::i1:
     case MVT::i8:
     case MVT::i16:
@@ -251,7 +252,7 @@
   unsigned ArgsSize = 0;
   for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; ++i) {
     switch (TheCall->getArg(i).getValueType().getSimpleVT()) {
-      default: assert(0 && "Unknown value type!");
+      default: LLVM_UNREACHABLE("Unknown value type!");
       case MVT::i1:
       case MVT::i8:
       case MVT::i16:
@@ -289,7 +290,7 @@
 
     // Promote the value if needed.
     switch (VA.getLocInfo()) {
-    default: assert(0 && "Unknown loc info!");
+    default: LLVM_UNREACHABLE("Unknown loc info!");
     case CCValAssign::Full: break;
     case CCValAssign::SExt:
       Arg = DAG.getNode(ISD::SIGN_EXTEND, VA.getLocVT(), Arg);
@@ -331,7 +332,7 @@
     SDValue ValToStore(0, 0);
     unsigned ObjSize;
     switch (ObjectVT.getSimpleVT()) {
-    default: assert(0 && "Unhandled argument type!");
+    default: LLVM_UNREACHABLE("Unhandled argument type!");
     case MVT::i32:
       ObjSize = 4;
 
@@ -497,7 +498,7 @@
 /// condition.
 static SPCC::CondCodes IntCondCCodeToICC(ISD::CondCode CC) {
   switch (CC) {
-  default: assert(0 && "Unknown integer condition code!");
+  default: LLVM_UNREACHABLE("Unknown integer condition code!");
   case ISD::SETEQ:  return SPCC::ICC_E;
   case ISD::SETNE:  return SPCC::ICC_NE;
   case ISD::SETLT:  return SPCC::ICC_L;
@@ -515,7 +516,7 @@
 /// FCC condition.
 static SPCC::CondCodes FPCondCCodeToFCC(ISD::CondCode CC) {
   switch (CC) {
-  default: assert(0 && "Unknown fp condition code!");
+  default: LLVM_UNREACHABLE("Unknown fp condition code!");
   case ISD::SETEQ:
   case ISD::SETOEQ: return SPCC::FCC_E;
   case ISD::SETNE:
@@ -901,12 +902,12 @@
 SDValue SparcTargetLowering::
 LowerOperation(SDValue Op, SelectionDAG &DAG) {
   switch (Op.getOpcode()) {
-  default: assert(0 && "Should not custom lower this!");
+  default: LLVM_UNREACHABLE("Should not custom lower this!");
   // Frame & Return address.  Currently unimplemented
   case ISD::RETURNADDR: return SDValue();
   case ISD::FRAMEADDR:  return SDValue();
   case ISD::GlobalTLSAddress:
-    assert(0 && "TLS not implemented for Sparc.");
+    LLVM_UNREACHABLE("TLS not implemented for Sparc.");
   case ISD::GlobalAddress:      return LowerGLOBALADDRESS(Op, DAG);
   case ISD::ConstantPool:       return LowerCONSTANTPOOL(Op, DAG);
   case ISD::FP_TO_SINT:         return LowerFP_TO_SINT(Op, DAG);
@@ -930,7 +931,7 @@
   DebugLoc dl = MI->getDebugLoc();
   // Figure out the conditional branch opcode to use for this select_cc.
   switch (MI->getOpcode()) {
-  default: assert(0 && "Unknown SELECT_CC!");
+  default: LLVM_UNREACHABLE("Unknown SELECT_CC!");
   case SP::SELECT_CC_Int_ICC:
   case SP::SELECT_CC_FP_ICC:
   case SP::SELECT_CC_DFP_ICC:
diff --git a/lib/Target/Sparc/SparcInstrInfo.cpp b/lib/Target/Sparc/SparcInstrInfo.cpp
index 12c286a..451c458 100644
--- a/lib/Target/Sparc/SparcInstrInfo.cpp
+++ b/lib/Target/Sparc/SparcInstrInfo.cpp
@@ -17,6 +17,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "SparcGenInstrInfo.inc"
 using namespace llvm;
 
@@ -160,7 +161,7 @@
     BuildMI(MBB, I, DL, get(SP::STDFri)).addFrameIndex(FI).addImm(0)
       .addReg(SrcReg,  getKillRegState(isKill));
   else
-    assert(0 && "Can't store this register to stack slot");
+    LLVM_UNREACHABLE("Can't store this register to stack slot");
 }
 
 void SparcInstrInfo::storeRegToAddr(MachineFunction &MF, unsigned SrcReg,
@@ -177,7 +178,7 @@
   else if (RC == SP::DFPRegsRegisterClass)
     Opc = SP::STDFri;
   else
-    assert(0 && "Can't load this register");
+    LLVM_UNREACHABLE("Can't load this register");
   MachineInstrBuilder MIB = BuildMI(MF, DL, get(Opc));
   for (unsigned i = 0, e = Addr.size(); i != e; ++i)
     MIB.addOperand(Addr[i]);
@@ -200,7 +201,7 @@
   else if (RC == SP::DFPRegsRegisterClass)
     BuildMI(MBB, I, DL, get(SP::LDDFri), DestReg).addFrameIndex(FI).addImm(0);
   else
-    assert(0 && "Can't load this register from stack slot");
+    LLVM_UNREACHABLE("Can't load this register from stack slot");
 }
 
 void SparcInstrInfo::loadRegFromAddr(MachineFunction &MF, unsigned DestReg,
@@ -215,7 +216,7 @@
   else if (RC == SP::DFPRegsRegisterClass)
     Opc = SP::LDDFri;
   else
-    assert(0 && "Can't load this register");
+    LLVM_UNREACHABLE("Can't load this register");
   DebugLoc DL = DebugLoc::getUnknownLoc();
   MachineInstrBuilder MIB = BuildMI(MF, DL, get(Opc), DestReg);
   for (unsigned i = 0, e = Addr.size(); i != e; ++i)
diff --git a/lib/Target/Sparc/SparcRegisterInfo.cpp b/lib/Target/Sparc/SparcRegisterInfo.cpp
index 59efb19..ab3c25e 100644
--- a/lib/Target/Sparc/SparcRegisterInfo.cpp
+++ b/lib/Target/Sparc/SparcRegisterInfo.cpp
@@ -18,6 +18,7 @@
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineLocation.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Type.h"
 #include "llvm/ADT/BitVector.h"
@@ -168,27 +169,27 @@
 }
 
 unsigned SparcRegisterInfo::getRARegister() const {
-  assert(0 && "What is the return address register");
+  LLVM_UNREACHABLE("What is the return address register");
   return 0;
 }
 
 unsigned SparcRegisterInfo::getFrameRegister(MachineFunction &MF) const {
-  assert(0 && "What is the frame register");
+  LLVM_UNREACHABLE("What is the frame register");
   return SP::G1;
 }
 
 unsigned SparcRegisterInfo::getEHExceptionRegister() const {
-  assert(0 && "What is the exception register");
+  LLVM_UNREACHABLE("What is the exception register");
   return 0;
 }
 
 unsigned SparcRegisterInfo::getEHHandlerRegister() const {
-  assert(0 && "What is the exception handler register");
+  LLVM_UNREACHABLE("What is the exception handler register");
   return 0;
 }
 
 int SparcRegisterInfo::getDwarfRegNum(unsigned RegNum, bool isEH) const {
-  assert(0 && "What is the dwarf register number");
+  LLVM_UNREACHABLE("What is the dwarf register number");
   return -1;
 }
 
diff --git a/lib/Target/TargetAsmInfo.cpp b/lib/Target/TargetAsmInfo.cpp
index 3f5f1bd..782e7b4 100644
--- a/lib/Target/TargetAsmInfo.cpp
+++ b/lib/Target/TargetAsmInfo.cpp
@@ -22,6 +22,7 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Support/Dwarf.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <cctype>
 #include <cstring>
 using namespace llvm;
@@ -276,7 +277,7 @@
       Flags |= SectionFlags::Small;
       break;
      default:
-      assert(0 && "Unexpected section kind!");
+      LLVM_UNREACHABLE("Unexpected section kind!");
     }
 
     if (GV->isWeakForLinker())
@@ -386,7 +387,7 @@
    case SectionKind::ThreadBSS:
     return ".gnu.linkonce.tb." + GV->getName();
    default:
-    assert(0 && "Unknown section kind");
+    LLVM_UNREACHABLE("Unknown section kind");
   }
   return NULL;
 }
diff --git a/lib/Target/TargetData.cpp b/lib/Target/TargetData.cpp
index 7dfa057..b3f2e98 100644
--- a/lib/Target/TargetData.cpp
+++ b/lib/Target/TargetData.cpp
@@ -23,6 +23,7 @@
 #include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/System/Mutex.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/StringExtras.h"
@@ -453,7 +454,7 @@
   case Type::VectorTyID:
     return cast<VectorType>(Ty)->getBitWidth();
   default:
-    assert(0 && "TargetData::getTypeSizeInBits(): Unsupported type");
+    LLVM_UNREACHABLE("TargetData::getTypeSizeInBits(): Unsupported type");
     break;
   }
   return 0;
@@ -508,7 +509,7 @@
     AlignType = VECTOR_ALIGN;
     break;
   default:
-    assert(0 && "Bad type for getAlignment!!!");
+    LLVM_UNREACHABLE("Bad type for getAlignment!!!");
     break;
   }
 
diff --git a/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp b/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp
index 4cd332b..b9f1dbd 100644
--- a/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp
+++ b/lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.cpp
@@ -33,6 +33,7 @@
 #include "llvm/CodeGen/DwarfWriter.h"
 #include "llvm/CodeGen/MachineJumpTableInfo.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Mangler.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetAsmInfo.h"
@@ -54,7 +55,7 @@
   else if (Subtarget->isTargetELF())
     O << ".Lllvm$" << getFunctionNumber() << ".$piclabel";
   else
-    assert(0 && "Don't know how to print PIC label!\n");
+    LLVM_UNREACHABLE( "Don't know how to print PIC label!\n");
 }
 
 /// PrintUnmangledNameSafely - Print out the printable characters in the name.
@@ -154,7 +155,7 @@
     }
     break;
   default:
-    assert(0 && "Unsupported DecorationStyle");
+    LLVM_UNREACHABLE( "Unsupported DecorationStyle");
   }
 }
 
@@ -166,7 +167,7 @@
 
   SwitchToSection(TAI->SectionForGlobal(F));
   switch (F->getLinkage()) {
-  default: assert(0 && "Unknown linkage type!");
+  default: LLVM_UNREACHABLE( "Unknown linkage type!");
   case Function::InternalLinkage:  // Symbols default to internal.
   case Function::PrivateLinkage:
     EmitAlignment(FnAlign, F);
@@ -292,7 +293,7 @@
 void X86ATTAsmPrinter::print_pcrel_imm(const MachineInstr *MI, unsigned OpNo) {
   const MachineOperand &MO = MI->getOperand(OpNo);
   switch (MO.getType()) {
-  default: assert(0 && "Unknown pcrel immediate operand");
+  default: LLVM_UNREACHABLE( "Unknown pcrel immediate operand");
   case MachineOperand::MO_Immediate:
     O << MO.getImm();
     return;
@@ -375,7 +376,7 @@
                                     const char *Modifier) {
   const MachineOperand &MO = MI->getOperand(OpNo);
   switch (MO.getType()) {
-  default: assert(0 && "unknown operand type!");
+  default: LLVM_UNREACHABLE( "unknown operand type!");
   case MachineOperand::MO_Register: {
     assert(TargetRegisterInfo::isPhysicalRegister(MO.getReg()) &&
            "Virtual registers should not make it this far!");
@@ -472,7 +473,7 @@
   
   switch (MO.getTargetFlags()) {
   default:
-    assert(0 && "Unknown target flag on GV operand");
+    LLVM_UNREACHABLE( "Unknown target flag on GV operand");
   case X86II::MO_NO_FLAG:    // No flag.
     break;
   case X86II::MO_DARWIN_NONLAZY:
@@ -775,7 +776,7 @@
       } else if (MO.isMBB()) {
         MCOp.MakeMBBLabel(getFunctionNumber(), MO.getMBB()->getNumber());
       } else {
-        assert(0 && "Unimp");
+        LLVM_UNREACHABLE( "Unimp");
       }
       
       TmpInst.addOperand(MCOp);
@@ -927,7 +928,7 @@
   case GlobalValue::InternalLinkage:
      break;
   default:
-    assert(0 && "Unknown linkage type!");
+    LLVM_UNREACHABLE( "Unknown linkage type!");
   }
 
   EmitAlignment(Align, GVar);
diff --git a/lib/Target/X86/AsmPrinter/X86ATTInstPrinter.cpp b/lib/Target/X86/AsmPrinter/X86ATTInstPrinter.cpp
index 5b10c7b..6b9167f 100644
--- a/lib/Target/X86/AsmPrinter/X86ATTInstPrinter.cpp
+++ b/lib/Target/X86/AsmPrinter/X86ATTInstPrinter.cpp
@@ -28,7 +28,7 @@
 
 void X86ATTAsmPrinter::printSSECC(const MCInst *MI, unsigned Op) {
   switch (MI->getOperand(Op).getImm()) {
-  default: assert(0 && "Invalid ssecc argument!");
+  default: LLVM_UNREACHABLE( "Invalid ssecc argument!");
   case 0: O << "eq"; break;
   case 1: O << "lt"; break;
   case 2: O << "le"; break;
@@ -42,7 +42,7 @@
 
 
 void X86ATTAsmPrinter::printPICLabel(const MCInst *MI, unsigned Op) {
-  assert(0 &&
+  LLVM_UNREACHABLE(
          "This is only used for MOVPC32r, should lower before asm printing!");
 }
 
@@ -61,7 +61,7 @@
     O << TAI->getPrivateGlobalPrefix() << "BB" << Op.getMBBLabelFunction()
       << '_' << Op.getMBBLabelBlock();
   else
-    assert(0 && "Unknown pcrel immediate operand");
+    LLVM_UNREACHABLE( "Unknown pcrel immediate operand");
 }
 
 
diff --git a/lib/Target/X86/AsmPrinter/X86IntelAsmPrinter.cpp b/lib/Target/X86/AsmPrinter/X86IntelAsmPrinter.cpp
index ad8d6ad..31b2654 100644
--- a/lib/Target/X86/AsmPrinter/X86IntelAsmPrinter.cpp
+++ b/lib/Target/X86/AsmPrinter/X86IntelAsmPrinter.cpp
@@ -26,6 +26,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Assembly/Writer.h"
 #include "llvm/CodeGen/DwarfWriter.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Mangler.h"
 #include "llvm/Target/TargetAsmInfo.h"
 #include "llvm/Target/TargetOptions.h"
@@ -114,7 +115,7 @@
 
     break;
   default:
-    assert(0 && "Unsupported DecorationStyle");
+    LLVM_UNREACHABLE( "Unsupported DecorationStyle");
   }
 }
 
@@ -143,7 +144,7 @@
 
   SwitchToTextSection("_text", F);
   switch (F->getLinkage()) {
-  default: assert(0 && "Unsupported linkage type!");
+  default: LLVM_UNREACHABLE( "Unsupported linkage type!");
   case Function::PrivateLinkage:
   case Function::InternalLinkage:
     EmitAlignment(FnAlign);
@@ -267,7 +268,7 @@
 void X86IntelAsmPrinter::print_pcrel_imm(const MachineInstr *MI, unsigned OpNo){
   const MachineOperand &MO = MI->getOperand(OpNo);
   switch (MO.getType()) {
-  default: assert(0 && "Unknown pcrel immediate operand");
+  default: LLVM_UNREACHABLE( "Unknown pcrel immediate operand");
   case MachineOperand::MO_Immediate:
     O << MO.getImm();
     return;
@@ -519,7 +520,7 @@
       SwitchToSection(TAI->getDataSection());
       break;
     default:
-      assert(0 && "Unknown linkage type!");
+      LLVM_UNREACHABLE( "Unknown linkage type!");
     }
 
     if (!bCustomSegment)
diff --git a/lib/Target/X86/X86CodeEmitter.cpp b/lib/Target/X86/X86CodeEmitter.cpp
index e3161e5..acaeea3 100644
--- a/lib/Target/X86/X86CodeEmitter.cpp
+++ b/lib/Target/X86/X86CodeEmitter.cpp
@@ -335,7 +335,7 @@
     unsigned rt = Is64BitMode ? X86::reloc_pcrel_word : X86::reloc_picrel_word;
     emitJumpTableAddress(RelocOp->getIndex(), rt, PCAdj);
   } else {
-    assert(0 && "Unknown value to relocate!");
+    LLVM_UNREACHABLE("Unknown value to relocate!");
   }
 }
 
@@ -478,7 +478,7 @@
   case X86II::GS:
     MCE.emitByte(0x65);
     break;
-  default: assert(0 && "Invalid segment!");
+  default: LLVM_UNREACHABLE("Invalid segment!");
   case 0: break;  // No segment override!
   }
 
@@ -513,7 +513,7 @@
                  (((Desc->TSFlags & X86II::Op0Mask)-X86II::D8)
                                    >> X86II::Op0Shift));
     break; // Two-byte opcode prefix
-  default: assert(0 && "Invalid prefix!");
+  default: LLVM_UNREACHABLE("Invalid prefix!");
   case 0: break;  // No prefix!
   }
 
@@ -548,13 +548,13 @@
 
   unsigned char BaseOpcode = II->getBaseOpcodeFor(Desc);
   switch (Desc->TSFlags & X86II::FormMask) {
-  default: assert(0 && "Unknown FormMask value in X86 MachineCodeEmitter!");
+  default: LLVM_UNREACHABLE("Unknown FormMask value in X86 MachineCodeEmitter!");
   case X86II::Pseudo:
     // Remember the current PC offset, this is the PIC relocation
     // base address.
     switch (Opcode) {
     default: 
-      assert(0 && "psuedo instructions should be removed before code emission");
+      LLVM_UNREACHABLE("psuedo instructions should be removed before code emission");
       break;
     case TargetInstrInfo::INLINEASM: {
       // We allow inline assembler nodes with empty bodies - they can
@@ -620,7 +620,7 @@
         } else
           emitConstant(MO.getImm(), X86InstrInfo::sizeOfImm(Desc));
       } else {
-        assert(0 && "Unknown RawFrm operand!");
+        LLVM_UNREACHABLE("Unknown RawFrm operand!");
       }
     }
     break;
diff --git a/lib/Target/X86/X86ELFWriterInfo.cpp b/lib/Target/X86/X86ELFWriterInfo.cpp
index 912ab0e..9be7021 100644
--- a/lib/Target/X86/X86ELFWriterInfo.cpp
+++ b/lib/Target/X86/X86ELFWriterInfo.cpp
@@ -14,6 +14,7 @@
 #include "X86ELFWriterInfo.h"
 #include "X86Relocations.h"
 #include "llvm/Function.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetMachine.h"
 
@@ -42,7 +43,7 @@
       return R_X86_64_64;
     case X86::reloc_picrel_word:
     default:
-      assert(0 && "unknown relocation type");
+      LLVM_UNREACHABLE("unknown relocation type");
     }
   } else {
     switch(MachineRelTy) {
@@ -53,7 +54,7 @@
     case X86::reloc_absolute_dword:
     case X86::reloc_picrel_word:
     default:
-      assert(0 && "unknown relocation type");
+      LLVM_UNREACHABLE("unknown relocation type");
     }
   }
   return 0;
@@ -65,7 +66,7 @@
     case R_X86_64_PC32: return -4;
       break;
     default:
-      assert(0 && "unknown x86 relocation type");
+      LLVM_UNREACHABLE("unknown x86 relocation type");
     }
   }
   return 0;
diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index f589220..feb3d4c 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -29,6 +29,7 @@
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/Support/CallSite.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Target/TargetOptions.h"
 using namespace llvm;
@@ -1318,7 +1319,7 @@
   
     // Promote the value if needed.
     switch (VA.getLocInfo()) {
-    default: assert(0 && "Unknown loc info!");
+    default: LLVM_UNREACHABLE("Unknown loc info!");
     case CCValAssign::Full: break;
     case CCValAssign::SExt: {
       bool Emitted = X86FastEmitExtend(ISD::SIGN_EXTEND, VA.getLocVT(),
diff --git a/lib/Target/X86/X86FloatingPoint.cpp b/lib/Target/X86/X86FloatingPoint.cpp
index 37027ee..c15e348 100644
--- a/lib/Target/X86/X86FloatingPoint.cpp
+++ b/lib/Target/X86/X86FloatingPoint.cpp
@@ -38,6 +38,7 @@
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/SmallPtrSet.h"
@@ -255,7 +256,7 @@
     case X86II::CompareFP:  handleCompareFP(I); break;
     case X86II::CondMovFP:  handleCondMovFP(I); break;
     case X86II::SpecialFP:  handleSpecialFP(I); break;
-    default: assert(0 && "Unknown FP Type!");
+    default: LLVM_UNREACHABLE("Unknown FP Type!");
     }
 
     // Check to see if any of the values defined by this instruction are dead
@@ -945,7 +946,7 @@
   MachineInstr *MI = I;
   DebugLoc dl = MI->getDebugLoc();
   switch (MI->getOpcode()) {
-  default: assert(0 && "Unknown SpecialFP instruction!");
+  default: LLVM_UNREACHABLE("Unknown SpecialFP instruction!");
   case X86::FpGET_ST0_32:// Appears immediately after a call returning FP type!
   case X86::FpGET_ST0_64:// Appears immediately after a call returning FP type!
   case X86::FpGET_ST0_80:// Appears immediately after a call returning FP type!
diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index b8cbbfa..5e2ff3f 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -1461,7 +1461,7 @@
       bool isSigned = Opcode == ISD::SMUL_LOHI;
       if (!isSigned)
         switch (NVT.getSimpleVT()) {
-        default: assert(0 && "Unsupported VT!");
+        default: LLVM_UNREACHABLE("Unsupported VT!");
         case MVT::i8:  Opc = X86::MUL8r;  MOpc = X86::MUL8m;  break;
         case MVT::i16: Opc = X86::MUL16r; MOpc = X86::MUL16m; break;
         case MVT::i32: Opc = X86::MUL32r; MOpc = X86::MUL32m; break;
@@ -1469,7 +1469,7 @@
         }
       else
         switch (NVT.getSimpleVT()) {
-        default: assert(0 && "Unsupported VT!");
+        default: LLVM_UNREACHABLE("Unsupported VT!");
         case MVT::i8:  Opc = X86::IMUL8r;  MOpc = X86::IMUL8m;  break;
         case MVT::i16: Opc = X86::IMUL16r; MOpc = X86::IMUL16m; break;
         case MVT::i32: Opc = X86::IMUL32r; MOpc = X86::IMUL32m; break;
@@ -1478,7 +1478,7 @@
 
       unsigned LoReg, HiReg;
       switch (NVT.getSimpleVT()) {
-      default: assert(0 && "Unsupported VT!");
+      default: LLVM_UNREACHABLE("Unsupported VT!");
       case MVT::i8:  LoReg = X86::AL;  HiReg = X86::AH;  break;
       case MVT::i16: LoReg = X86::AX;  HiReg = X86::DX;  break;
       case MVT::i32: LoReg = X86::EAX; HiReg = X86::EDX; break;
@@ -1567,7 +1567,7 @@
       bool isSigned = Opcode == ISD::SDIVREM;
       if (!isSigned)
         switch (NVT.getSimpleVT()) {
-        default: assert(0 && "Unsupported VT!");
+        default: LLVM_UNREACHABLE("Unsupported VT!");
         case MVT::i8:  Opc = X86::DIV8r;  MOpc = X86::DIV8m;  break;
         case MVT::i16: Opc = X86::DIV16r; MOpc = X86::DIV16m; break;
         case MVT::i32: Opc = X86::DIV32r; MOpc = X86::DIV32m; break;
@@ -1575,7 +1575,7 @@
         }
       else
         switch (NVT.getSimpleVT()) {
-        default: assert(0 && "Unsupported VT!");
+        default: LLVM_UNREACHABLE("Unsupported VT!");
         case MVT::i8:  Opc = X86::IDIV8r;  MOpc = X86::IDIV8m;  break;
         case MVT::i16: Opc = X86::IDIV16r; MOpc = X86::IDIV16m; break;
         case MVT::i32: Opc = X86::IDIV32r; MOpc = X86::IDIV32m; break;
@@ -1585,7 +1585,7 @@
       unsigned LoReg, HiReg;
       unsigned ClrOpcode, SExtOpcode;
       switch (NVT.getSimpleVT()) {
-      default: assert(0 && "Unsupported VT!");
+      default: LLVM_UNREACHABLE("Unsupported VT!");
       case MVT::i8:
         LoReg = X86::AL;  HiReg = X86::AH;
         ClrOpcode  = 0;
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 2c6a727..d14b1aa 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1426,7 +1426,7 @@
           }
         }
       } else {
-        assert(0 && "Unknown argument type!");
+        LLVM_UNREACHABLE("Unknown argument type!");
       }
 
       unsigned Reg = DAG.getMachineFunction().addLiveIn(VA.getLocReg(), RC);
@@ -1721,7 +1721,7 @@
 
     // Promote the value if needed.
     switch (VA.getLocInfo()) {
-    default: assert(0 && "Unknown loc info!");
+    default: LLVM_UNREACHABLE("Unknown loc info!");
     case CCValAssign::Full: break;
     case CCValAssign::SExt:
       Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
@@ -2167,7 +2167,7 @@
     }
 
     switch (SetCCOpcode) {
-    default: assert(0 && "Invalid integer condition!");
+    default: LLVM_UNREACHABLE("Invalid integer condition!");
     case ISD::SETEQ:  return X86::COND_E;
     case ISD::SETGT:  return X86::COND_G;
     case ISD::SETGE:  return X86::COND_GE;
@@ -2207,7 +2207,7 @@
   //  1 | 0 | 0 | X == Y
   //  1 | 1 | 1 | unordered
   switch (SetCCOpcode) {
-  default: assert(0 && "Condcode should be pre-legalized away");
+  default: LLVM_UNREACHABLE("Condcode should be pre-legalized away");
   case ISD::SETUEQ:
   case ISD::SETEQ:   return X86::COND_E;
   case ISD::SETOLT:              // flipped
@@ -4715,7 +4715,7 @@
                                Subtarget->is64Bit());
   }
   
-  assert(0 && "Unreachable");
+  LLVM_UNREACHABLE("Unreachable");
   return SDValue();
 }
 
@@ -5038,7 +5038,7 @@
   
   unsigned Opc;
   switch (DstTy.getSimpleVT()) {
-  default: assert(0 && "Invalid FP_TO_SINT to lower!");
+  default: LLVM_UNREACHABLE("Invalid FP_TO_SINT to lower!");
   case MVT::i16: Opc = X86ISD::FP_TO_INT16_IN_MEM; break;
   case MVT::i32: Opc = X86ISD::FP_TO_INT32_IN_MEM; break;
   case MVT::i64: Opc = X86ISD::FP_TO_INT64_IN_MEM; break;
@@ -5461,7 +5461,7 @@
         NEQ = DAG.getNode(Opc, dl, VT, Op0, Op1, DAG.getConstant(4, MVT::i8));
         return DAG.getNode(ISD::AND, dl, VT, ORD, NEQ);
       }
-      assert(0 && "Illegal FP comparison");
+      LLVM_UNREACHABLE("Illegal FP comparison");
     }
     // Handle all other FP comparisons here.
     return DAG.getNode(Opc, dl, VT, Op0, Op1, DAG.getConstant(SSECC, MVT::i8));
@@ -6397,7 +6397,7 @@
 
     switch (CC) {
     default:
-      assert(0 && "Unsupported calling convention");
+      LLVM_UNREACHABLE("Unsupported calling convention");
     case CallingConv::C:
     case CallingConv::X86_StdCall: {
       // Pass 'nest' parameter in ECX.
@@ -6646,7 +6646,7 @@
   DebugLoc dl = Op.getDebugLoc();
 
   switch (Op.getOpcode()) {
-  default: assert(0 && "Unknown ovf instruction!");
+  default: LLVM_UNREACHABLE("Unknown ovf instruction!");
   case ISD::SADDO:
     // A subtract of one will be selected as a INC. Note that INC doesn't
     // set CF, so we can't do this for UADDO.
@@ -6768,7 +6768,7 @@
 ///
 SDValue X86TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) {
   switch (Op.getOpcode()) {
-  default: assert(0 && "Should not custom lower this!");
+  default: LLVM_UNREACHABLE("Should not custom lower this!");
   case ISD::ATOMIC_CMP_SWAP:    return LowerCMP_SWAP(Op,DAG);
   case ISD::ATOMIC_LOAD_SUB:    return LowerLOAD_SUB(Op,DAG);
   case ISD::BUILD_VECTOR:       return LowerBUILD_VECTOR(Op, DAG);
@@ -7616,7 +7616,7 @@
     // Get the X86 opcode to use.
     unsigned Opc;
     switch (MI->getOpcode()) {
-    default: assert(0 && "illegal opcode!");
+    default: LLVM_UNREACHABLE("illegal opcode!");
     case X86::FP32_TO_INT16_IN_MEM: Opc = X86::IST_Fp16m32; break;
     case X86::FP32_TO_INT32_IN_MEM: Opc = X86::IST_Fp32m32; break;
     case X86::FP32_TO_INT64_IN_MEM: Opc = X86::IST_Fp64m32; break;
@@ -8355,7 +8355,7 @@
   SDValue  ValOp = N->getOperand(0);
   switch (N->getOpcode()) {
   default:
-    assert(0 && "Unknown shift opcode!");
+    LLVM_UNREACHABLE("Unknown shift opcode!");
     break;
   case ISD::SHL:
     if (VT == MVT::v2i64)
diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index 8bb9642..572b71d 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -1299,7 +1299,7 @@
     unsigned Opc;
     unsigned Size;
     switch (MI->getOpcode()) {
-    default: assert(0 && "Unreachable!");
+    default: LLVM_UNREACHABLE("Unreachable!");
     case X86::SHRD16rri8: Size = 16; Opc = X86::SHLD16rri8; break;
     case X86::SHLD16rri8: Size = 16; Opc = X86::SHRD16rri8; break;
     case X86::SHRD32rri8: Size = 32; Opc = X86::SHLD32rri8; break;
@@ -1454,7 +1454,7 @@
 
 unsigned X86::GetCondBranchFromCond(X86::CondCode CC) {
   switch (CC) {
-  default: assert(0 && "Illegal condition code!");
+  default: LLVM_UNREACHABLE("Illegal condition code!");
   case X86::COND_E:  return X86::JE;
   case X86::COND_NE: return X86::JNE;
   case X86::COND_L:  return X86::JL;
@@ -1478,7 +1478,7 @@
 /// e.g. turning COND_E to COND_NE.
 X86::CondCode X86::GetOppositeBranchCondition(X86::CondCode CC) {
   switch (CC) {
-  default: assert(0 && "Illegal condition code!");
+  default: LLVM_UNREACHABLE("Illegal condition code!");
   case X86::COND_E:  return X86::COND_NE;
   case X86::COND_NE: return X86::COND_E;
   case X86::COND_L:  return X86::COND_GE;
@@ -2644,7 +2644,7 @@
   case X86II::Imm16:  return 2;
   case X86II::Imm32:  return 4;
   case X86II::Imm64:  return 8;
-  default: assert(0 && "Immediate size not set!");
+  default: LLVM_UNREACHABLE("Immediate size not set!");
     return 0;
   }
 }
@@ -2829,7 +2829,7 @@
   } else if (RelocOp->isJTI()) {
     FinalSize += sizeJumpTableAddress(false);
   } else {
-    assert(0 && "Unknown value to relocate!");
+    LLVM_UNREACHABLE("Unknown value to relocate!");
   }
   return FinalSize;
 }
@@ -2926,7 +2926,7 @@
   case X86II::GS:
    ++FinalSize;
    break;
-  default: assert(0 && "Invalid segment!");
+  default: LLVM_UNREACHABLE("Invalid segment!");
   case 0: break;  // No segment override!
   }
 
@@ -2959,7 +2959,7 @@
   case X86II::DC: case X86II::DD: case X86II::DE: case X86II::DF:
     ++FinalSize;
     break; // Two-byte opcode prefix
-  default: assert(0 && "Invalid prefix!");
+  default: LLVM_UNREACHABLE("Invalid prefix!");
   case 0: break;  // No prefix!
   }
 
@@ -2993,7 +2993,7 @@
     --NumOps;
 
   switch (Desc->TSFlags & X86II::FormMask) {
-  default: assert(0 && "Unknown FormMask value in X86 MachineCodeEmitter!");
+  default: LLVM_UNREACHABLE("Unknown FormMask value in X86 MachineCodeEmitter!");
   case X86II::Pseudo:
     // Remember the current PC offset, this is the PIC relocation
     // base address.
@@ -3038,7 +3038,7 @@
       } else if (MO.isImm()) {
         FinalSize += sizeConstant(X86InstrInfo::sizeOfImm(Desc));
       } else {
-        assert(0 && "Unknown RawFrm operand!");
+        LLVM_UNREACHABLE("Unknown RawFrm operand!");
       }
     }
     break;
diff --git a/lib/Target/X86/X86JITInfo.cpp b/lib/Target/X86/X86JITInfo.cpp
index eb09def..5b44e4f 100644
--- a/lib/Target/X86/X86JITInfo.cpp
+++ b/lib/Target/X86/X86JITInfo.cpp
@@ -554,7 +554,7 @@
   TLSOffset -= size;
   return TLSOffset;
 #else
-  assert(0 && "Cannot allocate thread local storage on this arch!\n");
+  LLVM_UNREACHABLE("Cannot allocate thread local storage on this arch!\n");
   return 0;
 #endif
 }
diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index c9d3950..6bb05c5 100644
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -38,6 +38,7 @@
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
 X86RegisterInfo::X86RegisterInfo(X86TargetMachine &tm,
@@ -146,7 +147,7 @@
 
   default:
     assert(isVirtualRegister(RegNo) && "Unknown physical register!");
-    assert(0 && "Register allocator hasn't allocated reg correctly yet!");
+    LLVM_UNREACHABLE("Register allocator hasn't allocated reg correctly yet!");
     return 0;
   }
 }
@@ -973,7 +974,7 @@
   case X86::TAILJMPr:
   case X86::TAILJMPm: break;  // These are ok
   default:
-    assert(0 && "Can only insert epilog into returning blocks");
+    LLVM_UNREACHABLE("Can only insert epilog into returning blocks");
   }
 
   // Get the number of bytes to allocate from the FrameInfo
@@ -1126,12 +1127,12 @@
 }
 
 unsigned X86RegisterInfo::getEHExceptionRegister() const {
-  assert(0 && "What is the exception register");
+  LLVM_UNREACHABLE("What is the exception register");
   return 0;
 }
 
 unsigned X86RegisterInfo::getEHHandlerRegister() const {
-  assert(0 && "What is the exception handler register");
+  LLVM_UNREACHABLE("What is the exception handler register");
   return 0;
 }
 
diff --git a/lib/Target/X86/X86TargetAsmInfo.cpp b/lib/Target/X86/X86TargetAsmInfo.cpp
index f49ca15..4b24ccc 100644
--- a/lib/Target/X86/X86TargetAsmInfo.cpp
+++ b/lib/Target/X86/X86TargetAsmInfo.cpp
@@ -21,6 +21,7 @@
 #include "llvm/Module.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/Dwarf.h"
+#include "llvm/Support/ErrorHandling.h"
 
 using namespace llvm;
 using namespace llvm::dwarf;
@@ -280,7 +281,7 @@
    case SectionKind::RODataMergeStr:
     return ".rdata$linkonce" + GV->getName();
    default:
-    assert(0 && "Unknown section kind");
+    LLVM_UNREACHABLE("Unknown section kind");
   }
   return NULL;
 }
diff --git a/lib/Target/XCore/XCoreAsmPrinter.cpp b/lib/Target/XCore/XCoreAsmPrinter.cpp
index 6f2af77..5234a9b 100644
--- a/lib/Target/XCore/XCoreAsmPrinter.cpp
+++ b/lib/Target/XCore/XCoreAsmPrinter.cpp
@@ -255,7 +255,7 @@
   O << "\t.cc_top " << CurrentFnName << ".function," << CurrentFnName << "\n";
 
   switch (F->getLinkage()) {
-  default: assert(0 && "Unknown linkage type!");
+  default: LLVM_UNREACHABLE("Unknown linkage type!");
   case Function::InternalLinkage:  // Symbols default to internal.
   case Function::PrivateLinkage:
     break;
@@ -358,7 +358,7 @@
     if (TargetRegisterInfo::isPhysicalRegister(MO.getReg()))
       O << TM.getRegisterInfo()->get(MO.getReg()).AsmName;
     else
-      assert(0 && "not implemented");
+      LLVM_UNREACHABLE("not implemented");
     break;
   case MachineOperand::MO_Immediate:
     O << MO.getImm();
@@ -381,7 +381,7 @@
       << '_' << MO.getIndex();
     break;
   default:
-    assert(0 && "not implemented");
+    LLVM_UNREACHABLE("not implemented");
   }
 }
 
@@ -410,7 +410,7 @@
   if (printInstruction(MI)) {
     return;
   }
-  assert(0 && "Unhandled instruction in asm writer!");
+  LLVM_UNREACHABLE("Unhandled instruction in asm writer!");
 }
 
 bool XCoreAsmPrinter::doInitialization(Module &M) {
diff --git a/lib/Target/XCore/XCoreISelLowering.cpp b/lib/Target/XCore/XCoreISelLowering.cpp
index df5006b..c2cc09c 100644
--- a/lib/Target/XCore/XCoreISelLowering.cpp
+++ b/lib/Target/XCore/XCoreISelLowering.cpp
@@ -167,7 +167,7 @@
   case ISD::SUB:              return ExpandADDSUB(Op.getNode(), DAG);
   case ISD::FRAMEADDR:        return LowerFRAMEADDR(Op, DAG);
   default:
-    assert(0 && "unimplemented operand");
+    LLVM_UNREACHABLE("unimplemented operand");
     return SDValue();
   }
 }
@@ -179,7 +179,7 @@
                                              SelectionDAG &DAG) {
   switch (N->getOpcode()) {
   default:
-    assert(0 && "Don't know how to custom expand this!");
+    LLVM_UNREACHABLE("Don't know how to custom expand this!");
     return;
   case ISD::ADD:
   case ISD::SUB:
@@ -266,7 +266,7 @@
       GVar = dyn_cast_or_null<GlobalVariable>(GA->resolveAliasedGlobal());
   }
   if (! GVar) {
-    assert(0 && "Thread local object not a GlobalVariable?");
+    LLVM_UNREACHABLE("Thread local object not a GlobalVariable?");
     return SDValue();
   }
   const Type *Ty = cast<PointerType>(GV->getType())->getElementType();
@@ -292,7 +292,7 @@
   // FIXME there isn't really debug info here
   DebugLoc dl = CP->getDebugLoc();
   if (Subtarget.isXS1A()) {
-    assert(0 && "Lowering of constant pool unimplemented");
+    LLVM_UNREACHABLE("Lowering of constant pool unimplemented");
     return SDValue();
   } else {
     MVT PtrVT = Op.getValueType();
@@ -356,7 +356,7 @@
 SDValue XCoreTargetLowering::
 LowerVAARG(SDValue Op, SelectionDAG &DAG)
 {
-  assert(0 && "unimplemented");
+  LLVM_UNREACHABLE("unimplemented");
   // FIX Arguments passed by reference need a extra dereference.
   SDNode *Node = Op.getNode();
   DebugLoc dl = Node->getDebugLoc();
@@ -426,7 +426,7 @@
   switch (CallingConv) 
   {
     default:
-      assert(0 && "Unsupported calling convention");
+      LLVM_UNREACHABLE("Unsupported calling convention");
     case CallingConv::Fast:
     case CallingConv::C:
       return LowerCCCCallTo(Op, DAG, CallingConv);
@@ -474,7 +474,7 @@
 
     // Promote the value if needed.
     switch (VA.getLocInfo()) {
-      default: assert(0 && "Unknown loc info!");
+      default: LLVM_UNREACHABLE("Unknown loc info!");
       case CCValAssign::Full: break;
       case CCValAssign::SExt:
         Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, VA.getLocVT(), Arg);
@@ -607,7 +607,7 @@
   switch(CC) 
   {
     default:
-      assert(0 && "Unsupported calling convention");
+      LLVM_UNREACHABLE("Unsupported calling convention");
     case CallingConv::C:
     case CallingConv::Fast:
       return LowerCCCArguments(Op, DAG);
diff --git a/lib/Target/XCore/XCoreInstrInfo.cpp b/lib/Target/XCore/XCoreInstrInfo.cpp
index 504d202..147d29d 100644
--- a/lib/Target/XCore/XCoreInstrInfo.cpp
+++ b/lib/Target/XCore/XCoreInstrInfo.cpp
@@ -21,6 +21,7 @@
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "XCoreGenInstrInfo.inc"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 
 namespace llvm {
 namespace XCore {
@@ -186,7 +187,7 @@
 static inline unsigned GetCondBranchFromCond(XCore::CondCode CC) 
 {
   switch (CC) {
-  default: assert(0 && "Illegal condition code!");
+  default: LLVM_UNREACHABLE("Illegal condition code!");
   case XCore::COND_TRUE   : return XCore::BRFT_lru6;
   case XCore::COND_FALSE  : return XCore::BRFF_lru6;
   }
@@ -197,7 +198,7 @@
 static inline XCore::CondCode GetOppositeBranchCondition(XCore::CondCode CC)
 {
   switch (CC) {
-  default: assert(0 && "Illegal condition code!");
+  default: LLVM_UNREACHABLE("Illegal condition code!");
   case XCore::COND_TRUE   : return XCore::COND_FALSE;
   case XCore::COND_FALSE  : return XCore::COND_TRUE;
   }
@@ -407,7 +408,7 @@
                             const TargetRegisterClass *RC,
                             SmallVectorImpl<MachineInstr*> &NewMIs) const
 {
-  assert(0 && "unimplemented\n");
+  LLVM_UNREACHABLE("unimplemented\n");
 }
 
 void XCoreInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
@@ -427,7 +428,7 @@
                               const TargetRegisterClass *RC,
                               SmallVectorImpl<MachineInstr*> &NewMIs) const
 {
-  assert(0 && "unimplemented\n");
+  LLVM_UNREACHABLE("unimplemented\n");
 }
 
 bool XCoreInstrInfo::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
diff --git a/lib/Target/XCore/XCoreRegisterInfo.cpp b/lib/Target/XCore/XCoreRegisterInfo.cpp
index 9bf99ac..f0ff246 100644
--- a/lib/Target/XCore/XCoreRegisterInfo.cpp
+++ b/lib/Target/XCore/XCoreRegisterInfo.cpp
@@ -257,7 +257,7 @@
               .addReg(ScratchReg, RegState::Kill);
         break;
       default:
-        assert(0 && "Unexpected Opcode\n");
+        LLVM_UNREACHABLE("Unexpected Opcode\n");
       }
     } else {
       switch (MI.getOpcode()) {
@@ -278,7 +278,7 @@
               .addImm(Offset);
         break;
       default:
-        assert(0 && "Unexpected Opcode\n");
+        LLVM_UNREACHABLE("Unexpected Opcode\n");
       }
     }
   } else {
@@ -309,7 +309,7 @@
             .addImm(Offset);
       break;
     default:
-      assert(0 && "Unexpected Opcode\n");
+      LLVM_UNREACHABLE("Unexpected Opcode\n");
     }
   }
   // Erase old instruction.
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 366005b..57a8d28 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -28,6 +28,7 @@
 #include "llvm/Support/CallSite.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/ADT/DenseMap.h"
@@ -882,7 +883,7 @@
           Value *LV = new LoadInst(InitBool, InitBool->getName()+".val", CI);
           InitBoolUsed = true;
           switch (CI->getPredicate()) {
-          default: assert(0 && "Unknown ICmp Predicate!");
+          default: LLVM_UNREACHABLE("Unknown ICmp Predicate!");
           case ICmpInst::ICMP_ULT:
           case ICmpInst::ICMP_SLT:
             LV = Context->getConstantIntFalse();   // X < null -> always false
@@ -1163,7 +1164,7 @@
                             PN->getName()+".f"+utostr(FieldNo), PN);
     PHIsToRewrite.push_back(std::make_pair(PN, FieldNo));
   } else {
-    assert(0 && "Unknown usable value");
+    LLVM_UNREACHABLE("Unknown usable value");
     Result = 0;
   }
   
@@ -2056,7 +2057,7 @@
       for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
         Elts.push_back(Context->getUndef(STy->getElementType(i)));
     } else {
-      assert(0 && "This code is out of sync with "
+      LLVM_UNREACHABLE("This code is out of sync with "
              " ConstantFoldLoadThroughGEPConstantExpr");
     }
     
@@ -2084,7 +2085,7 @@
       Constant *Elt = Context->getUndef(ATy->getElementType());
       Elts.assign(ATy->getNumElements(), Elt);
     } else {
-      assert(0 && "This code is out of sync with "
+      LLVM_UNREACHABLE("This code is out of sync with "
              " ConstantFoldLoadThroughGEPConstantExpr");
     }
     
diff --git a/lib/Transforms/IPO/MergeFunctions.cpp b/lib/Transforms/IPO/MergeFunctions.cpp
index 9d87403..31e36d8 100644
--- a/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/lib/Transforms/IPO/MergeFunctions.cpp
@@ -53,6 +53,7 @@
 #include "llvm/Support/CallSite.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <map>
 #include <vector>
 using namespace llvm;
@@ -128,7 +129,7 @@
     return false;
 
   default:
-    assert(0 && "Unknown type!");
+    LLVM_UNREACHABLE("Unknown type!");
     return false;
 
   case Type::PointerTyID: {
@@ -469,7 +470,7 @@
     return ExternalStrong;
   }
 
-  assert(0 && "Unknown LinkageType.");
+  LLVM_UNREACHABLE("Unknown LinkageType.");
   return ExternalWeak;
 }
 
@@ -575,7 +576,7 @@
     case Internal:
       switch (catG) {
         case ExternalStrong:
-          assert(0);
+          llvm_unreachable();
           // fall-through
         case ExternalWeak:
 	  if (F->hasAddressTaken())
diff --git a/lib/Transforms/Instrumentation/RSProfiling.cpp b/lib/Transforms/Instrumentation/RSProfiling.cpp
index c1f29fe..51a0bae 100644
--- a/lib/Transforms/Instrumentation/RSProfiling.cpp
+++ b/lib/Transforms/Instrumentation/RSProfiling.cpp
@@ -44,6 +44,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Transforms/Instrumentation.h"
 #include "RSProfiling.h"
 #include <set>
@@ -407,7 +408,7 @@
     TransCache[v] = v;
     return v;
   }
-  assert(0 && "Value not handled");
+  LLVM_UNREACHABLE("Value not handled");
   return 0;
 }
 
diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index b2fdd24..f0d131c 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -37,6 +37,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/Local.h"
 #include <cstdio>
@@ -201,7 +202,7 @@
 Expression::ExpressionOpcode ValueTable::getOpcode(BinaryOperator* BO) {
   switch(BO->getOpcode()) {
   default: // THIS SHOULD NEVER HAPPEN
-    assert(0 && "Binary operator with unknown opcode?");
+    LLVM_UNREACHABLE("Binary operator with unknown opcode?");
   case Instruction::Add:  return Expression::ADD;
   case Instruction::FAdd: return Expression::FADD;
   case Instruction::Sub:  return Expression::SUB;
@@ -227,7 +228,7 @@
   if (isa<ICmpInst>(C)) {
     switch (C->getPredicate()) {
     default:  // THIS SHOULD NEVER HAPPEN
-      assert(0 && "Comparison with unknown predicate?");
+      LLVM_UNREACHABLE("Comparison with unknown predicate?");
     case ICmpInst::ICMP_EQ:  return Expression::ICMPEQ;
     case ICmpInst::ICMP_NE:  return Expression::ICMPNE;
     case ICmpInst::ICMP_UGT: return Expression::ICMPUGT;
@@ -242,7 +243,7 @@
   } else {
     switch (C->getPredicate()) {
     default: // THIS SHOULD NEVER HAPPEN
-      assert(0 && "Comparison with unknown predicate?");
+      LLVM_UNREACHABLE("Comparison with unknown predicate?");
     case FCmpInst::FCMP_OEQ: return Expression::FCMPOEQ;
     case FCmpInst::FCMP_OGT: return Expression::FCMPOGT;
     case FCmpInst::FCMP_OGE: return Expression::FCMPOGE;
@@ -264,7 +265,7 @@
 Expression::ExpressionOpcode ValueTable::getOpcode(CastInst* C) {
   switch(C->getOpcode()) {
   default: // THIS SHOULD NEVER HAPPEN
-    assert(0 && "Cast operator with unknown opcode?");
+    LLVM_UNREACHABLE("Cast operator with unknown opcode?");
   case Instruction::Trunc:    return Expression::TRUNC;
   case Instruction::ZExt:     return Expression::ZEXT;
   case Instruction::SExt:     return Expression::SEXT;
diff --git a/lib/Transforms/Scalar/GVNPRE.cpp b/lib/Transforms/Scalar/GVNPRE.cpp
index af7e039..d5098f2 100644
--- a/lib/Transforms/Scalar/GVNPRE.cpp
+++ b/lib/Transforms/Scalar/GVNPRE.cpp
@@ -39,6 +39,7 @@
 #include "llvm/Support/CFG.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <algorithm>
 #include <deque>
 #include <map>
@@ -240,7 +241,7 @@
     
     // THIS SHOULD NEVER HAPPEN
     default:
-      assert(0 && "Binary operator with unknown opcode?");
+      LLVM_UNREACHABLE("Binary operator with unknown opcode?");
       return Expression::ADD;
   }
 }
@@ -271,7 +272,7 @@
       
       // THIS SHOULD NEVER HAPPEN
       default:
-        assert(0 && "Comparison with unknown predicate?");
+        LLVM_UNREACHABLE("Comparison with unknown predicate?");
         return Expression::ICMPEQ;
     }
   } else {
@@ -307,7 +308,7 @@
       
       // THIS SHOULD NEVER HAPPEN
       default:
-        assert(0 && "Comparison with unknown predicate?");
+        LLVM_UNREACHABLE("Comparison with unknown predicate?");
         return Expression::FCMPOEQ;
     }
   }
@@ -343,7 +344,7 @@
     
     // THIS SHOULD NEVER HAPPEN
     default:
-      assert(0 && "Cast operator with unknown opcode?");
+      LLVM_UNREACHABLE("Cast operator with unknown opcode?");
       return Expression::BITCAST;
   }
 }
@@ -577,7 +578,7 @@
   if (VI != valueNumbering.end())
     return VI->second;
   else
-    assert(0 && "Value not numbered?");
+    LLVM_UNREACHABLE("Value not numbered?");
   
   return 0;
 }
@@ -767,7 +768,7 @@
     if (v == VN.lookup(*I))
       return *I;
   
-  assert(0 && "No leader found, but present bit is set?");
+  LLVM_UNREACHABLE("No leader found, but present bit is set?");
   return 0;
 }
 
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 89881f7..6aa6530 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -1679,7 +1679,7 @@
     
     UndefElts = UndefElts2;
     if (VWidth > InVWidth) {
-      assert(0 && "Unimp");
+      LLVM_UNREACHABLE("Unimp");
       // If there are more elements in the result than there are in the source,
       // then an output element is undef if the corresponding input element is
       // undef.
@@ -1687,7 +1687,7 @@
         if (UndefElts2[OutIdx/Ratio])
           UndefElts.set(OutIdx);
     } else if (VWidth < InVWidth) {
-      assert(0 && "Unimp");
+      LLVM_UNREACHABLE("Unimp");
       // If there are more elements in the source than there are in the result,
       // then a result element is undef if all of the corresponding input
       // elements are undef.
@@ -1757,7 +1757,7 @@
           RHS = InsertNewInstBefore(new ExtractElementInst(RHS, 0U,"tmp"), *II);
           
           switch (II->getIntrinsicID()) {
-          default: assert(0 && "Case stmts out of sync!");
+          default: LLVM_UNREACHABLE("Case stmts out of sync!");
           case Intrinsic::x86_sse_sub_ss:
           case Intrinsic::x86_sse2_sub_sd:
             TmpV = InsertNewInstBefore(BinaryOperator::CreateFSub(LHS, RHS,
@@ -2019,7 +2019,7 @@
                                 PN->getIncomingValue(i), C, "phitmp",
                                 NonConstBB->getTerminator());
         else
-          assert(0 && "Unknown binop!");
+          LLVM_UNREACHABLE("Unknown binop!");
         
         AddToWorkList(cast<Instruction>(InV));
       }
@@ -3355,7 +3355,7 @@
   case ICmpInst::ICMP_SLE: return 6;  // 110
     // True -> 7
   default:
-    assert(0 && "Invalid ICmp predicate!");
+    LLVM_UNREACHABLE("Invalid ICmp predicate!");
     return 0;
   }
 }
@@ -3383,7 +3383,7 @@
     // True -> 7
   default:
     // Not expecting FCMP_FALSE and FCMP_TRUE;
-    assert(0 && "Unexpected FCmp predicate!");
+    LLVM_UNREACHABLE("Unexpected FCmp predicate!");
     return 0;
   }
 }
@@ -3395,7 +3395,7 @@
 static Value *getICmpValue(bool sign, unsigned code, Value *LHS, Value *RHS,
                            LLVMContext *Context) {
   switch (code) {
-  default: assert(0 && "Illegal ICmp code!");
+  default: LLVM_UNREACHABLE("Illegal ICmp code!");
   case  0: return Context->getConstantIntFalse();
   case  1: 
     if (sign)
@@ -3429,7 +3429,7 @@
 static Value *getFCmpValue(bool isordered, unsigned code,
                            Value *LHS, Value *RHS, LLVMContext *Context) {
   switch (code) {
-  default: assert(0 && "Illegal FCmp code!");
+  default: LLVM_UNREACHABLE("Illegal FCmp code!");
   case  0:
     if (isordered)
       return new FCmpInst(*Context, FCmpInst::FCMP_ORD, LHS, RHS);
@@ -3508,7 +3508,7 @@
     case Instruction::And: Code = LHSCode & RHSCode; break;
     case Instruction::Or:  Code = LHSCode | RHSCode; break;
     case Instruction::Xor: Code = LHSCode ^ RHSCode; break;
-    default: assert(0 && "Illegal logical opcode!"); return 0;
+    default: LLVM_UNREACHABLE("Illegal logical opcode!"); return 0;
     }
 
     bool isSigned = ICmpInst::isSignedPredicate(RHSICI->getPredicate()) || 
@@ -3843,10 +3843,10 @@
   assert(LHSCst != RHSCst && "Compares not folded above?");
 
   switch (LHSCC) {
-  default: assert(0 && "Unknown integer condition code!");
+  default: LLVM_UNREACHABLE("Unknown integer condition code!");
   case ICmpInst::ICMP_EQ:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:         // (X == 13 & X == 15) -> false
     case ICmpInst::ICMP_UGT:        // (X == 13 & X >  15) -> false
     case ICmpInst::ICMP_SGT:        // (X == 13 & X >  15) -> false
@@ -3858,7 +3858,7 @@
     }
   case ICmpInst::ICMP_NE:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_ULT:
       if (LHSCst == SubOne(RHSCst, Context)) // (X != 13 & X u< 14) -> X < 13
         return new ICmpInst(*Context, ICmpInst::ICMP_ULT, Val, LHSCst);
@@ -3885,7 +3885,7 @@
     break;
   case ICmpInst::ICMP_ULT:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:         // (X u< 13 & X == 15) -> false
     case ICmpInst::ICMP_UGT:        // (X u< 13 & X u> 15) -> false
       return ReplaceInstUsesWith(I, Context->getConstantIntFalse());
@@ -3900,7 +3900,7 @@
     break;
   case ICmpInst::ICMP_SLT:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:         // (X s< 13 & X == 15) -> false
     case ICmpInst::ICMP_SGT:        // (X s< 13 & X s> 15) -> false
       return ReplaceInstUsesWith(I, Context->getConstantIntFalse());
@@ -3915,7 +3915,7 @@
     break;
   case ICmpInst::ICMP_UGT:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:         // (X u> 13 & X == 15) -> X == 15
     case ICmpInst::ICMP_UGT:        // (X u> 13 & X u> 15) -> X u> 15
       return ReplaceInstUsesWith(I, RHS);
@@ -3934,7 +3934,7 @@
     break;
   case ICmpInst::ICMP_SGT:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:         // (X s> 13 & X == 15) -> X == 15
     case ICmpInst::ICMP_SGT:        // (X s> 13 & X s> 15) -> X s> 15
       return ReplaceInstUsesWith(I, RHS);
@@ -4532,10 +4532,10 @@
   assert(LHSCst != RHSCst && "Compares not folded above?");
 
   switch (LHSCC) {
-  default: assert(0 && "Unknown integer condition code!");
+  default: LLVM_UNREACHABLE("Unknown integer condition code!");
   case ICmpInst::ICMP_EQ:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:
       if (LHSCst == SubOne(RHSCst, Context)) {
         // (X == 13 | X == 14) -> X-13 <u 2
@@ -4558,7 +4558,7 @@
     break;
   case ICmpInst::ICMP_NE:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:          // (X != 13 | X == 15) -> X != 13
     case ICmpInst::ICMP_UGT:         // (X != 13 | X u> 15) -> X != 13
     case ICmpInst::ICMP_SGT:         // (X != 13 | X s> 15) -> X != 13
@@ -4571,7 +4571,7 @@
     break;
   case ICmpInst::ICMP_ULT:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:         // (X u< 13 | X == 14) -> no change
       break;
     case ICmpInst::ICMP_UGT:        // (X u< 13 | X u> 15) -> (X-13) u> 2
@@ -4592,7 +4592,7 @@
     break;
   case ICmpInst::ICMP_SLT:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:         // (X s< 13 | X == 14) -> no change
       break;
     case ICmpInst::ICMP_SGT:        // (X s< 13 | X s> 15) -> (X-13) s> 2
@@ -4613,7 +4613,7 @@
     break;
   case ICmpInst::ICMP_UGT:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:         // (X u> 13 | X == 15) -> X u> 13
     case ICmpInst::ICMP_UGT:        // (X u> 13 | X u> 15) -> X u> 13
       return ReplaceInstUsesWith(I, LHS);
@@ -4628,7 +4628,7 @@
     break;
   case ICmpInst::ICMP_SGT:
     switch (RHSCC) {
-    default: assert(0 && "Unknown integer condition code!");
+    default: LLVM_UNREACHABLE("Unknown integer condition code!");
     case ICmpInst::ICMP_EQ:         // (X s> 13 | X == 15) -> X > 13
     case ICmpInst::ICMP_SGT:        // (X s> 13 | X s> 15) -> X > 13
       return ReplaceInstUsesWith(I, LHS);
@@ -5704,7 +5704,7 @@
   
   ICmpInst::Predicate Pred;
   switch (I.getPredicate()) {
-  default: assert(0 && "Unexpected predicate!");
+  default: LLVM_UNREACHABLE("Unexpected predicate!");
   case FCmpInst::FCMP_UEQ:
   case FCmpInst::FCMP_OEQ:
     Pred = ICmpInst::ICMP_EQ;
@@ -5798,7 +5798,7 @@
       // the compare predicate and sometimes the value.  RHSC is rounded towards
       // zero at this point.
       switch (Pred) {
-      default: assert(0 && "Unexpected integer comparison!");
+      default: LLVM_UNREACHABLE("Unexpected integer comparison!");
       case ICmpInst::ICMP_NE:  // (float)int != 4.4   --> true
         return ReplaceInstUsesWith(I, Context->getConstantIntTrue());
       case ICmpInst::ICMP_EQ:  // (float)int == 4.4   --> false
@@ -5875,7 +5875,7 @@
   // Simplify 'fcmp pred X, X'
   if (Op0 == Op1) {
     switch (I.getPredicate()) {
-    default: assert(0 && "Unknown predicate!");
+    default: LLVM_UNREACHABLE("Unknown predicate!");
     case FCmpInst::FCMP_UEQ:    // True if unordered or equal
     case FCmpInst::FCMP_UGE:    // True if unordered, greater than, or equal
     case FCmpInst::FCMP_ULE:    // True if unordered, less than, or equal
@@ -5994,7 +5994,7 @@
   // icmp's with boolean values can always be turned into bitwise operations
   if (Ty == Type::Int1Ty) {
     switch (I.getPredicate()) {
-    default: assert(0 && "Invalid icmp instruction!");
+    default: LLVM_UNREACHABLE("Invalid icmp instruction!");
     case ICmpInst::ICMP_EQ: {               // icmp eq i1 A, B -> ~(A^B)
       Instruction *Xor = BinaryOperator::CreateXor(Op0, Op1, I.getName()+"tmp");
       InsertNewInstBefore(Xor, I);
@@ -6136,7 +6136,7 @@
     // Based on the range information we know about the LHS, see if we can
     // simplify this comparison.  For example, (x&4) < 8  is always true.
     switch (I.getPredicate()) {
-    default: assert(0 && "Unknown icmp opcode!");
+    default: LLVM_UNREACHABLE("Unknown icmp opcode!");
     case ICmpInst::ICMP_EQ:
       if (Op0Max.ult(Op1Min) || Op0Min.ugt(Op1Max))
         return ReplaceInstUsesWith(I, Context->getConstantIntFalse());
@@ -6645,7 +6645,7 @@
 
   Value *X = DivI->getOperand(0);
   switch (Pred) {
-  default: assert(0 && "Unhandled icmp opcode!");
+  default: LLVM_UNREACHABLE("Unhandled icmp opcode!");
   case ICmpInst::ICMP_EQ:
     if (LoOverflow && HiOverflow)
       return ReplaceInstUsesWith(ICI, Context->getConstantIntFalse());
@@ -8081,7 +8081,7 @@
   }
   default: 
     // TODO: Can handle more cases here.
-    assert(0 && "Unreachable!");
+    LLVM_UNREACHABLE("Unreachable!");
     break;
   }
   
@@ -8296,7 +8296,7 @@
     default:
       // All the others use floating point so we shouldn't actually 
       // get here because of the check above.
-      assert(0 && "Unknown cast type");
+      LLVM_UNREACHABLE("Unknown cast type");
     case Instruction::Trunc:
       DoXForm = true;
       break;
@@ -8352,7 +8352,7 @@
 
       assert(Res->getType() == DestTy);
       switch (CI.getOpcode()) {
-      default: assert(0 && "Unknown cast type!");
+      default: LLVM_UNREACHABLE("Unknown cast type!");
       case Instruction::Trunc:
       case Instruction::BitCast:
         // Just replace this cast with the result.
@@ -9196,7 +9196,7 @@
     else
       return BinaryOperator::Create(BO->getOpcode(), NewSI, MatchOp);
   }
-  assert(0 && "Shouldn't get here");
+  LLVM_UNREACHABLE("Shouldn't get here");
   return 0;
 }
 
@@ -9238,7 +9238,7 @@
             NewSel->takeName(TVI);
             if (BinaryOperator *BO = dyn_cast<BinaryOperator>(TVI))
               return BinaryOperator::Create(BO->getOpcode(), FalseVal, NewSel);
-            assert(0 && "Unknown instruction!!");
+            LLVM_UNREACHABLE("Unknown instruction!!");
           }
         }
       }
@@ -9267,7 +9267,7 @@
             NewSel->takeName(FVI);
             if (BinaryOperator *BO = dyn_cast<BinaryOperator>(FVI))
               return BinaryOperator::Create(BO->getOpcode(), TrueVal, NewSel);
-            assert(0 && "Unknown instruction!!");
+            LLVM_UNREACHABLE("Unknown instruction!!");
           }
         }
       }
diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index 2de64c1..e521be2 100644
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -456,7 +456,7 @@
     } else if (SCValue.isConstant())
       Succs[SI->findCaseValue(cast<ConstantInt>(SCValue.getConstant()))] = true;
   } else {
-    assert(0 && "SCCP: Don't know how to handle this terminator!");
+    LLVM_UNREACHABLE("SCCP: Don't know how to handle this terminator!");
   }
 }
 
@@ -1806,7 +1806,7 @@
           } else if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
             assert(isa<UndefValue>(SI->getCondition()) && "Switch should fold");
           } else {
-            assert(0 && "Didn't fold away reference to block!");
+            LLVM_UNREACHABLE("Didn't fold away reference to block!");
           }
 #endif
           
diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index da2c375..2c97e57 100644
--- a/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -267,7 +267,7 @@
       // Check that all of the users of the allocation are capable of being
       // transformed.
       switch (isSafeAllocaToScalarRepl(AI)) {
-      default: assert(0 && "Unexpected value!");
+      default: LLVM_UNREACHABLE("Unexpected value!");
       case 0:  // Not safe to scalar replace.
         break;
       case 1:  // Safe, but requires cleanup/canonicalizations first
diff --git a/lib/Transforms/Utils/BreakCriticalEdges.cpp b/lib/Transforms/Utils/BreakCriticalEdges.cpp
index c4fd1ea..f45f24c 100644
--- a/lib/Transforms/Utils/BreakCriticalEdges.cpp
+++ b/lib/Transforms/Utils/BreakCriticalEdges.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Type.h"
 #include "llvm/Support/CFG.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 using namespace llvm;
@@ -222,8 +223,8 @@
     // If NewBBDominatesDestBB hasn't been computed yet, do so with DF.
     if (!OtherPreds.empty()) {
       // FIXME: IMPLEMENT THIS!
-      assert(0 && "Requiring domfrontiers but not idom/domtree/domset."
-             " not implemented yet!");
+      LLVM_UNREACHABLE("Requiring domfrontiers but not idom/domtree/domset."
+                       " not implemented yet!");
     }
     
     // Since the new block is dominated by its only predecessor TIBB,
diff --git a/lib/Transforms/Utils/ValueMapper.cpp b/lib/Transforms/Utils/ValueMapper.cpp
index 21b3a22..951d24f 100644
--- a/lib/Transforms/Utils/ValueMapper.cpp
+++ b/lib/Transforms/Utils/ValueMapper.cpp
@@ -20,6 +20,7 @@
 #include "llvm/LLVMContext.h"
 #include "llvm/MDNode.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
 Value *llvm::MapValue(const Value *V, ValueMapTy &VM, LLVMContext *Context) {
@@ -126,7 +127,7 @@
       return VM[V] = C;
 
     } else {
-      assert(0 && "Unknown type of constant!");
+      LLVM_UNREACHABLE("Unknown type of constant!");
     }
   }
 
diff --git a/lib/VMCore/AsmWriter.cpp b/lib/VMCore/AsmWriter.cpp
index face5a1..959da81 100644
--- a/lib/VMCore/AsmWriter.cpp
+++ b/lib/VMCore/AsmWriter.cpp
@@ -97,7 +97,7 @@
                           unsigned NameLen, PrefixType Prefix) {
   assert(NameStr && "Cannot get empty name!");
   switch (Prefix) {
-  default: assert(0 && "Bad prefix!");
+  default: LLVM_UNREACHABLE("Bad prefix!");
   case NoPrefix: break;
   case GlobalPrefix: OS << '@'; break;
   case LabelPrefix:  break;
@@ -937,7 +937,7 @@
     else if (&CFP->getValueAPF().getSemantics() == &APFloat::PPCDoubleDouble)
       Out << 'M';
     else
-      assert(0 && "Unsupported floating point type");
+      LLVM_UNREACHABLE("Unsupported floating point type");
     // api needed to prevent premature destruction
     APInt api = CFP->getValueAPF().bitcastToAPInt();
     const uint64_t* p = api.getRawData();
@@ -1210,7 +1210,7 @@
     else if (const Function *F = dyn_cast<Function>(G))
       printFunction(F);
     else
-      assert(0 && "Unknown global");
+      LLVM_UNREACHABLE("Unknown global");
   }
   
   void write(const BasicBlock *BB)    { printBasicBlock(BB);  }
@@ -1358,7 +1358,7 @@
 static void PrintVisibility(GlobalValue::VisibilityTypes Vis,
                             raw_ostream &Out) {
   switch (Vis) {
-  default: assert(0 && "Invalid visibility style!");
+  default: LLVM_UNREACHABLE("Invalid visibility style!");
   case GlobalValue::DefaultVisibility: break;
   case GlobalValue::HiddenVisibility:    Out << "hidden "; break;
   case GlobalValue::ProtectedVisibility: Out << "protected "; break;
@@ -1969,7 +1969,7 @@
   } else if (isa<InlineAsm>(this)) {
     WriteAsOperand(OS, this, true, 0);
   } else {
-    assert(0 && "Unknown value to print out!");
+    LLVM_UNREACHABLE("Unknown value to print out!");
   }
 }
 
diff --git a/lib/VMCore/AutoUpgrade.cpp b/lib/VMCore/AutoUpgrade.cpp
index 378df83..f3aa742 100644
--- a/lib/VMCore/AutoUpgrade.cpp
+++ b/lib/VMCore/AutoUpgrade.cpp
@@ -19,6 +19,7 @@
 #include "llvm/Instructions.h"
 #include "llvm/Intrinsics.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <cstring>
 using namespace llvm;
 
@@ -333,13 +334,13 @@
       //  Clean up the old call now that it has been completely upgraded.
       CI->eraseFromParent();
     } else {
-      assert(0 && "Unknown function for CallInst upgrade.");
+      LLVM_UNREACHABLE("Unknown function for CallInst upgrade.");
     }
     return;
   }
 
   switch (NewFn->getIntrinsicID()) {
-  default:  assert(0 && "Unknown function for CallInst upgrade.");
+  default:  LLVM_UNREACHABLE("Unknown function for CallInst upgrade.");
   case Intrinsic::x86_mmx_psll_d:
   case Intrinsic::x86_mmx_psll_q:
   case Intrinsic::x86_mmx_psll_w:
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index e019e6c..3919643 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -26,6 +26,7 @@
 #include "llvm/GlobalAlias.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/GetElementPtrTypeIterator.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MathExtras.h"
@@ -306,7 +307,7 @@
     break;
   }
 
-  assert(0 && "Failed to cast constant expression");
+  LLVM_UNREACHABLE("Failed to cast constant expression");
   return 0;
 }
 
@@ -1304,7 +1305,7 @@
     APInt V1 = cast<ConstantInt>(C1)->getValue();
     APInt V2 = cast<ConstantInt>(C2)->getValue();
     switch (pred) {
-    default: assert(0 && "Invalid ICmp Predicate"); return 0;
+    default: LLVM_UNREACHABLE("Invalid ICmp Predicate"); return 0;
     case ICmpInst::ICMP_EQ: return ConstantInt::get(Type::Int1Ty, V1 == V2);
     case ICmpInst::ICMP_NE: return ConstantInt::get(Type::Int1Ty, V1 != V2);
     case ICmpInst::ICMP_SLT:return ConstantInt::get(Type::Int1Ty, V1.slt(V2));
@@ -1321,7 +1322,7 @@
     APFloat C2V = cast<ConstantFP>(C2)->getValueAPF();
     APFloat::cmpResult R = C1V.compare(C2V);
     switch (pred) {
-    default: assert(0 && "Invalid FCmp Predicate"); return 0;
+    default: LLVM_UNREACHABLE("Invalid FCmp Predicate"); return 0;
     case FCmpInst::FCMP_FALSE: return ConstantInt::getFalse();
     case FCmpInst::FCMP_TRUE:  return ConstantInt::getTrue();
     case FCmpInst::FCMP_UNO:
@@ -1377,7 +1378,7 @@
   if (C1->getType()->isFloatingPoint()) {
     int Result = -1;  // -1 = unknown, 0 = known false, 1 = known true.
     switch (evaluateFCmpRelation(C1, C2)) {
-    default: assert(0 && "Unknown relation!");
+    default: LLVM_UNREACHABLE("Unknown relation!");
     case FCmpInst::FCMP_UNO:
     case FCmpInst::FCMP_ORD:
     case FCmpInst::FCMP_UEQ:
@@ -1436,7 +1437,7 @@
     // Evaluate the relation between the two constants, per the predicate.
     int Result = -1;  // -1 = unknown, 0 = known false, 1 = known true.
     switch (evaluateICmpRelation(C1, C2, CmpInst::isSigned(pred))) {
-    default: assert(0 && "Unknown relational!");
+    default: LLVM_UNREACHABLE("Unknown relational!");
     case ICmpInst::BAD_ICMP_PREDICATE:
       break;  // Couldn't determine anything about these constants.
     case ICmpInst::ICMP_EQ:   // We know the constants are equal!
diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 78ef3a8..0f3239b 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -1939,7 +1939,7 @@
       if (V.opcode == Instruction::FCmp) 
         return new CompareConstantExpr(Ty, Instruction::FCmp, V.predicate, 
                                        V.operands[0], V.operands[1]);
-      assert(0 && "Invalid ConstantExpr!");
+      LLVM_UNREACHABLE("Invalid ConstantExpr!");
       return 0;
     }
   };
@@ -2030,7 +2030,7 @@
 
   switch (opc) {
     default:
-      assert(0 && "Invalid cast opcode");
+      LLVM_UNREACHABLE("Invalid cast opcode");
       break;
     case Instruction::Trunc:    return getTrunc(C, Ty);
     case Instruction::ZExt:     return getZExt(C, Ty);
@@ -2287,7 +2287,7 @@
 Constant *ConstantExpr::getCompareTy(unsigned short predicate,
                                      Constant *C1, Constant *C2) {
   switch (predicate) {
-    default: assert(0 && "Invalid CmpInst predicate");
+    default: LLVM_UNREACHABLE("Invalid CmpInst predicate");
     case CmpInst::FCMP_FALSE: case CmpInst::FCMP_OEQ: case CmpInst::FCMP_OGT:
     case CmpInst::FCMP_OGE:   case CmpInst::FCMP_OLT: case CmpInst::FCMP_OLE:
     case CmpInst::FCMP_ONE:   case CmpInst::FCMP_ORD: case CmpInst::FCMP_UNO:
@@ -2894,7 +2894,7 @@
     if (C2 == From) C2 = To;
     Replacement = ConstantExpr::get(getOpcode(), C1, C2);
   } else {
-    assert(0 && "Unknown ConstantExpr type!");
+    LLVM_UNREACHABLE("Unknown ConstantExpr type!");
     return;
   }
   
diff --git a/lib/VMCore/Core.cpp b/lib/VMCore/Core.cpp
index 0e3d7e8..068735e 100644
--- a/lib/VMCore/Core.cpp
+++ b/lib/VMCore/Core.cpp
@@ -25,6 +25,7 @@
 #include "llvm/IntrinsicInst.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/CallSite.h"
+#include "llvm/Support/ErrorHandling.h"
 #include <cassert>
 #include <cstdlib>
 #include <cstring>
@@ -1062,7 +1063,7 @@
     return CI->getCallingConv();
   else if (InvokeInst *II = dyn_cast<InvokeInst>(V))
     return II->getCallingConv();
-  assert(0 && "LLVMGetInstructionCallConv applies only to call and invoke!");
+  LLVM_UNREACHABLE("LLVMGetInstructionCallConv applies only to call and invoke!");
   return 0;
 }
 
@@ -1072,7 +1073,7 @@
     return CI->setCallingConv(CC);
   else if (InvokeInst *II = dyn_cast<InvokeInst>(V))
     return II->setCallingConv(CC);
-  assert(0 && "LLVMSetInstructionCallConv applies only to call and invoke!");
+  LLVM_UNREACHABLE("LLVMSetInstructionCallConv applies only to call and invoke!");
 }
 
 void LLVMAddInstrAttribute(LLVMValueRef Instr, unsigned index, 
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index b56168a..475d8cd 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -2705,7 +2705,7 @@
   APInt Upper(C);
   uint32_t BitWidth = C.getBitWidth();
   switch (pred) {
-  default: assert(0 && "Invalid ICmp opcode to ConstantRange ctor!");
+  default: LLVM_UNREACHABLE("Invalid ICmp opcode to ConstantRange ctor!");
   case ICmpInst::ICMP_EQ: Upper++; break;
   case ICmpInst::ICMP_NE: Lower++; break;
   case ICmpInst::ICMP_ULT: Lower = APInt::getMinValue(BitWidth); break;
diff --git a/lib/VMCore/PassManager.cpp b/lib/VMCore/PassManager.cpp
index 0878694..a454b56 100644
--- a/lib/VMCore/PassManager.cpp
+++ b/lib/VMCore/PassManager.cpp
@@ -724,7 +724,7 @@
     OtherDT.dump();
     cerr << "----- Invalid -----\n";
     DT->dump();
-    assert(0 && "Invalid dominator info");
+    LLVM_UNREACHABLE("Invalid dominator info");
   }
 
   DominanceFrontier *DF = P.getAnalysisIfAvailable<DominanceFrontier>();
@@ -741,7 +741,7 @@
     OtherDF.dump();
     cerr << "----- Invalid -----\n";
     DF->dump();
-    assert(0 && "Invalid dominator info");
+    LLVM_UNREACHABLE("Invalid dominator info");
   }
 }
 
@@ -883,7 +883,7 @@
       // Keep track of higher level analysis used by this manager.
       HigherLevelAnalysis.push_back(PRequired);
     } else 
-      assert(0 && "Unable to accomodate Required Pass");
+      LLVM_UNREACHABLE("Unable to accomodate Required Pass");
   }
 
   // Set P as P's last user until someone starts using P.
@@ -1106,7 +1106,7 @@
   cerr << "Unable to schedule '" << RequiredPass->getPassName();
   cerr << "' required by '" << P->getPassName() << "'\n";
 #endif
-  assert(0 && "Unable to schedule pass");
+  LLVM_UNREACHABLE("Unable to schedule pass");
 }
 
 // Destructor
diff --git a/lib/VMCore/Type.cpp b/lib/VMCore/Type.cpp
index 8daaf91..c94e911 100644
--- a/lib/VMCore/Type.cpp
+++ b/lib/VMCore/Type.cpp
@@ -634,7 +634,7 @@
     }
     return true;
   } else {
-    assert(0 && "Unknown derived type!");
+    LLVM_UNREACHABLE("Unknown derived type!");
     return false;
   }
 }
diff --git a/lib/VMCore/ValueTypes.cpp b/lib/VMCore/ValueTypes.cpp
index 3c3a293..4a51208 100644
--- a/lib/VMCore/ValueTypes.cpp
+++ b/lib/VMCore/ValueTypes.cpp
@@ -16,6 +16,7 @@
 #include "llvm/LLVMContext.h"
 #include "llvm/Type.h"
 #include "llvm/DerivedTypes.h"
+#include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
 MVT MVT::getExtendedIntegerVT(unsigned BitWidth) {
@@ -90,7 +91,7 @@
              getVectorElementType().getMVTString();
     if (isInteger())
       return "i" + utostr(getSizeInBits());
-    assert(0 && "Invalid MVT!");
+    LLVM_UNREACHABLE("Invalid MVT!");
     return "?";
   case MVT::i1:      return "i1";
   case MVT::i8:      return "i8";
@@ -213,7 +214,7 @@
   switch (Ty->getTypeID()) {
   default:
     if (HandleUnknown) return MVT::Other;
-    assert(0 && "Unknown type!");
+    LLVM_UNREACHABLE("Unknown type!");
     return MVT::isVoid;
   case Type::VoidTyID:
     return MVT::isVoid;
diff --git a/lib/VMCore/Verifier.cpp b/lib/VMCore/Verifier.cpp
index 5d800af..1f43569 100644
--- a/lib/VMCore/Verifier.cpp
+++ b/lib/VMCore/Verifier.cpp
@@ -208,7 +208,7 @@
       if (!Broken) return false;
       msgs << "Broken module found, ";
       switch (action) {
-      default: assert(0 && "Unknown action");
+      default: LLVM_UNREACHABLE("Unknown action");
       case AbortProcessAction:
         msgs << "compilation aborted!\n";
         cerr << msgs.str();
@@ -1117,7 +1117,7 @@
             "Shift return type must be same as operands!", &B);
     break;
   default:
-    assert(0 && "Unknown BinaryOperator opcode!");
+    LLVM_UNREACHABLE("Unknown BinaryOperator opcode!");
   }
 
   visitInstruction(B);