diff --git a/include/clang/Analysis/CFG.h b/include/clang/Analysis/CFG.h
index d6dc453..611348f 100644
--- a/include/clang/Analysis/CFG.h
+++ b/include/clang/Analysis/CFG.h
@@ -49,7 +49,6 @@
 public:
   enum Kind {
     // main kind
-    Invalid,
     Statement,
     Initializer,
     // dtor kind
@@ -70,8 +69,8 @@
     : Data1(const_cast<void*>(Ptr1), ((unsigned) kind) & 0x3),
       Data2(const_cast<void*>(Ptr2), (((unsigned) kind) >> 2) & 0x3) {}
 
-public:
   CFGElement() {}
+public:
 
   /// \brief Convert to the specified CFGElement type, asserting that this
   /// CFGElement is of the desired type.
@@ -84,12 +83,12 @@
     return t;
   }
 
-  /// \brief Convert to the specified CFGElement type, returning an invalid
-  /// CFGElement if this CFGElement is not of the desired type.
+  /// \brief Convert to the specified CFGElement type, returning None if this
+  /// CFGElement is not of the desired type.
   template<typename T>
-  T getAs() const {
+  Optional<T> getAs() const {
     if (!T::isKind(*this))
-      return T();
+      return None;
     T t;
     CFGElement& e = t;
     e = *this;
@@ -102,10 +101,6 @@
     x |= Data1.getInt();
     return (Kind) x;
   }
-
-  bool isValid() const { return getKind() != Invalid; }
-
-  operator bool() const { return isValid(); }
 };
 
 class CFGStmt : public CFGElement {
@@ -574,7 +569,7 @@
   // the elements beginning at the last position in prepared space.
   iterator beginAutomaticObjDtorsInsert(iterator I, size_t Cnt,
       BumpVectorContext &C) {
-    return iterator(Elements.insert(I.base(), Cnt, CFGElement(), C));
+    return iterator(Elements.insert(I.base(), Cnt, CFGAutomaticObjDtor(0, 0), C));
   }
   iterator insertAutomaticObjDtor(iterator I, VarDecl *VD, Stmt *S) {
     *I = CFGAutomaticObjDtor(VD, S);
@@ -757,8 +752,8 @@
     for (const_iterator I=begin(), E=end(); I != E; ++I)
       for (CFGBlock::const_iterator BI=(*I)->begin(), BE=(*I)->end();
            BI != BE; ++BI) {
-        if (CFGStmt stmt = BI->getAs<CFGStmt>())
-          O(const_cast<Stmt*>(stmt.getStmt()));
+        if (Optional<CFGStmt> stmt = BI->getAs<CFGStmt>())
+          O(const_cast<Stmt*>(stmt->getStmt()));
       }
   }
 
diff --git a/include/clang/Analysis/ProgramPoint.h b/include/clang/Analysis/ProgramPoint.h
index 3fbe8e1..11b79a1 100644
--- a/include/clang/Analysis/ProgramPoint.h
+++ b/include/clang/Analysis/ProgramPoint.h
@@ -202,9 +202,9 @@
     return reinterpret_cast<const CFGBlock*>(getData1());
   }
 
-  const CFGElement getFirstElement() const {
+  Optional<CFGElement> getFirstElement() const {
     const CFGBlock *B = getBlock();
-    return B->empty() ? CFGElement() : B->front();
+    return B->empty() ? Optional<CFGElement>() : B->front();
   }
   
 private:
diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index 8754fe8..4d20467 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -3332,7 +3332,6 @@
 const CXXDestructorDecl *
 CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const {
   switch (getKind()) {
-    case CFGElement::Invalid:
     case CFGElement::Statement:
     case CFGElement::Initializer:
       llvm_unreachable("getDestructorDecl should only be used with "
@@ -3406,8 +3405,8 @@
 
   for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I)
     for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI)
-      if (CFGStmt S = BI->getAs<CFGStmt>())
-        FindSubExprAssignments(S.getStmt(), SubExprAssignments);
+      if (Optional<CFGStmt> S = BI->getAs<CFGStmt>())
+        FindSubExprAssignments(S->getStmt(), SubExprAssignments);
 
   for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) {
 
@@ -3415,10 +3414,10 @@
     // block-level that are block-level expressions.
 
     for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) {
-      CFGStmt CS = BI->getAs<CFGStmt>();
+      Optional<CFGStmt> CS = BI->getAs<CFGStmt>();
       if (!CS)
         continue;
-      if (const Expr *Exp = dyn_cast<Expr>(CS.getStmt())) {
+      if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) {
         assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps");
 
         if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) {
@@ -3531,8 +3530,8 @@
       unsigned j = 1;
       for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ;
            BI != BEnd; ++BI, ++j ) {        
-        if (CFGStmt SE = BI->getAs<CFGStmt>()) {
-          const Stmt *stmt= SE.getStmt();
+        if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) {
+          const Stmt *stmt= SE->getStmt();
           std::pair<unsigned, unsigned> P((*I)->getBlockID(), j);
           StmtMap[stmt] = P;
 
@@ -3721,8 +3720,8 @@
 
 static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper,
                        const CFGElement &E) {
-  if (CFGStmt CS = E.getAs<CFGStmt>()) {
-    const Stmt *S = CS.getStmt();
+  if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) {
+    const Stmt *S = CS->getStmt();
     
     if (Helper) {
 
@@ -3769,8 +3768,8 @@
     if (isa<Expr>(S))
       OS << '\n';
 
-  } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) {
-    const CXXCtorInitializer *I = IE.getInitializer();
+  } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) {
+    const CXXCtorInitializer *I = IE->getInitializer();
     if (I->isBaseInitializer())
       OS << I->getBaseClass()->getAsCXXRecordDecl()->getName();
     else OS << I->getAnyMember()->getName();
@@ -3784,8 +3783,9 @@
       OS << " (Base initializer)\n";
     else OS << " (Member initializer)\n";
 
-  } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){
-    const VarDecl *VD = DE.getVarDecl();
+  } else if (Optional<CFGAutomaticObjDtor> DE =
+                 E.getAs<CFGAutomaticObjDtor>()) {
+    const VarDecl *VD = DE->getVarDecl();
     Helper->handleDecl(VD, OS);
 
     const Type* T = VD->getType().getTypePtr();
@@ -3796,20 +3796,20 @@
     OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()";
     OS << " (Implicit destructor)\n";
 
-  } else if (CFGBaseDtor BE = E.getAs<CFGBaseDtor>()) {
-    const CXXBaseSpecifier *BS = BE.getBaseSpecifier();
+  } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) {
+    const CXXBaseSpecifier *BS = BE->getBaseSpecifier();
     OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()";
     OS << " (Base object destructor)\n";
 
-  } else if (CFGMemberDtor ME = E.getAs<CFGMemberDtor>()) {
-    const FieldDecl *FD = ME.getFieldDecl();
+  } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) {
+    const FieldDecl *FD = ME->getFieldDecl();
     const Type *T = FD->getType()->getBaseElementTypeUnsafe();
     OS << "this->" << FD->getName();
     OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()";
     OS << " (Member object destructor)\n";
 
-  } else if (CFGTemporaryDtor TE = E.getAs<CFGTemporaryDtor>()) {
-    const CXXBindTemporaryExpr *BT = TE.getBindTemporaryExpr();
+  } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) {
+    const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr();
     OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()";
     OS << " (Temporary object destructor)\n";
   }
diff --git a/lib/Analysis/CFGStmtMap.cpp b/lib/Analysis/CFGStmtMap.cpp
index 7daeef9..87c2f5b 100644
--- a/lib/Analysis/CFGStmtMap.cpp
+++ b/lib/Analysis/CFGStmtMap.cpp
@@ -50,11 +50,11 @@
   // First walk the block-level expressions.
   for (CFGBlock::iterator I = B->begin(), E = B->end(); I != E; ++I) {
     const CFGElement &CE = *I;
-    CFGStmt CS = CE.getAs<CFGStmt>();
+    Optional<CFGStmt> CS = CE.getAs<CFGStmt>();
     if (!CS)
       continue;
     
-    CFGBlock *&Entry = SM[CS.getStmt()];
+    CFGBlock *&Entry = SM[CS->getStmt()];
     // If 'Entry' is already initialized (e.g., a terminator was already),
     // skip.
     if (Entry)
diff --git a/lib/Analysis/LiveVariables.cpp b/lib/Analysis/LiveVariables.cpp
index 519d528..b43892a 100644
--- a/lib/Analysis/LiveVariables.cpp
+++ b/lib/Analysis/LiveVariables.cpp
@@ -474,8 +474,9 @@
        ei = block->rend(); it != ei; ++it) {
     const CFGElement &elem = *it;
 
-    if (CFGAutomaticObjDtor Dtor = elem.getAs<CFGAutomaticObjDtor>()){
-      val.liveDecls = DSetFact.add(val.liveDecls, Dtor.getVarDecl());
+    if (Optional<CFGAutomaticObjDtor> Dtor =
+            elem.getAs<CFGAutomaticObjDtor>()) {
+      val.liveDecls = DSetFact.add(val.liveDecls, Dtor->getVarDecl());
       continue;
     }
 
@@ -534,8 +535,9 @@
     if (killAtAssign)
       for (CFGBlock::const_iterator bi = block->begin(), be = block->end();
            bi != be; ++bi) {
-        if (CFGStmt cs = bi->getAs<CFGStmt>()) {
-          if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(cs.getStmt())) {
+        if (Optional<CFGStmt> cs = bi->getAs<CFGStmt>()) {
+          if (const BinaryOperator *BO =
+                  dyn_cast<BinaryOperator>(cs->getStmt())) {
             if (BO->getOpcode() == BO_Assign) {
               if (const DeclRefExpr *DR =
                     dyn_cast<DeclRefExpr>(BO->getLHS()->IgnoreParens())) {
diff --git a/lib/Analysis/ReachableCode.cpp b/lib/Analysis/ReachableCode.cpp
index f85e2de..a90aebb 100644
--- a/lib/Analysis/ReachableCode.cpp
+++ b/lib/Analysis/ReachableCode.cpp
@@ -95,8 +95,8 @@
 
 const Stmt *DeadCodeScan::findDeadCode(const clang::CFGBlock *Block) {
   for (CFGBlock::const_iterator I = Block->begin(), E = Block->end(); I!=E; ++I)
-    if (CFGStmt CS = I->getAs<CFGStmt>()) {
-      const Stmt *S = CS.getStmt();
+    if (Optional<CFGStmt> CS = I->getAs<CFGStmt>()) {
+      const Stmt *S = CS->getStmt();
       if (isValidDeadStmt(S))
         return S;
     }
diff --git a/lib/Analysis/ThreadSafety.cpp b/lib/Analysis/ThreadSafety.cpp
index 2e3abc0..7bb54d6 100644
--- a/lib/Analysis/ThreadSafety.cpp
+++ b/lib/Analysis/ThreadSafety.cpp
@@ -1397,8 +1397,8 @@
       for (CFGBlock::const_reverse_iterator BI = CurrBlock->rbegin(),
            BE = CurrBlock->rend(); BI != BE; ++BI) {
         // FIXME: Handle other CFGElement kinds.
-        if (CFGStmt CS = BI->getAs<CFGStmt>()) {
-          CurrBlockInfo->ExitLoc = CS.getStmt()->getLocStart();
+        if (Optional<CFGStmt> CS = BI->getAs<CFGStmt>()) {
+          CurrBlockInfo->ExitLoc = CS->getStmt()->getLocStart();
           break;
         }
       }
@@ -1410,8 +1410,8 @@
       for (CFGBlock::const_iterator BI = CurrBlock->begin(),
            BE = CurrBlock->end(); BI != BE; ++BI) {
         // FIXME: Handle other CFGElement kinds.
-        if (CFGStmt CS = BI->getAs<CFGStmt>()) {
-          CurrBlockInfo->EntryLoc = CS.getStmt()->getLocStart();
+        if (Optional<CFGStmt> CS = BI->getAs<CFGStmt>()) {
+          CurrBlockInfo->EntryLoc = CS->getStmt()->getLocStart();
           break;
         }
       }
@@ -2234,8 +2234,8 @@
     return false;
 
   CFGElement Last = B->back();
-  if (CFGStmt S = Last.getAs<CFGStmt>()) {
-    if (isa<CXXThrowExpr>(S.getStmt()))
+  if (Optional<CFGStmt> S = Last.getAs<CFGStmt>()) {
+    if (isa<CXXThrowExpr>(S->getStmt()))
       return true;
   }
   return false;
diff --git a/lib/Analysis/UninitializedValues.cpp b/lib/Analysis/UninitializedValues.cpp
index 022bb7d..730aa6b 100644
--- a/lib/Analysis/UninitializedValues.cpp
+++ b/lib/Analysis/UninitializedValues.cpp
@@ -746,9 +746,8 @@
   TransferFunctions tf(vals, cfg, block, ac, classification, handler);
   for (CFGBlock::const_iterator I = block->begin(), E = block->end(); 
        I != E; ++I) {
-    if (CFGStmt cs = I->getAs<CFGStmt>()) {
-      tf.Visit(const_cast<Stmt*>(cs.getStmt()));
-    }
+    if (Optional<CFGStmt> cs = I->getAs<CFGStmt>())
+      tf.Visit(const_cast<Stmt*>(cs->getStmt()));
   }
   return vals.updateValueVectorWithScratch(block);
 }
diff --git a/lib/Sema/AnalysisBasedWarnings.cpp b/lib/Sema/AnalysisBasedWarnings.cpp
index 9a67d49..50feef8 100644
--- a/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/lib/Sema/AnalysisBasedWarnings.cpp
@@ -762,8 +762,8 @@
           for (CFGBlock::const_reverse_iterator ElemIt = P->rbegin(),
                                                 ElemEnd = P->rend();
                ElemIt != ElemEnd; ++ElemIt) {
-            if (CFGStmt CS = ElemIt->getAs<CFGStmt>()) {
-              if (const AttributedStmt *AS = asFallThroughAttr(CS.getStmt())) {
+            if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>()) {
+              if (const AttributedStmt *AS = asFallThroughAttr(CS->getStmt())) {
                 S.Diag(AS->getLocStart(),
                        diag::warn_fallthrough_attr_unreachable);
                 markFallthroughVisited(AS);
@@ -833,8 +833,8 @@
       for (CFGBlock::const_reverse_iterator ElemIt = B.rbegin(),
                                             ElemEnd = B.rend();
                                             ElemIt != ElemEnd; ++ElemIt) {
-        if (CFGStmt CS = ElemIt->getAs<CFGStmt>())
-          return CS.getStmt();
+        if (Optional<CFGStmt> CS = ElemIt->getAs<CFGStmt>())
+          return CS->getStmt();
       }
       // Workaround to detect a statement thrown out by CFGBuilder:
       //   case X: {} case Y:
diff --git a/lib/StaticAnalyzer/Checkers/AnalyzerStatsChecker.cpp b/lib/StaticAnalyzer/Checkers/AnalyzerStatsChecker.cpp
index 217d467..9af0a5a 100644
--- a/lib/StaticAnalyzer/Checkers/AnalyzerStatsChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/AnalyzerStatsChecker.cpp
@@ -123,14 +123,14 @@
     const BlockEdge &BE =  I->first;
     const CFGBlock *Exit = BE.getDst();
     const CFGElement &CE = Exit->front();
-    if (CFGStmt CS = CE.getAs<CFGStmt>()) {
+    if (Optional<CFGStmt> CS = CE.getAs<CFGStmt>()) {
       SmallString<128> bufI;
       llvm::raw_svector_ostream outputI(bufI);
       outputI << "(" << NameOfRootFunction << ")" <<
                  ": The analyzer generated a sink at this point";
-      B.EmitBasicReport(D, "Sink Point", "Internal Statistics", outputI.str(),
-                        PathDiagnosticLocation::createBegin(CS.getStmt(),
-                                                            SM, LC));
+      B.EmitBasicReport(
+          D, "Sink Point", "Internal Statistics", outputI.str(),
+          PathDiagnosticLocation::createBegin(CS->getStmt(), SM, LC));
     }
   }
 }
diff --git a/lib/StaticAnalyzer/Checkers/MallocOverflowSecurityChecker.cpp b/lib/StaticAnalyzer/Checkers/MallocOverflowSecurityChecker.cpp
index 7b63d67..34425e3 100644
--- a/lib/StaticAnalyzer/Checkers/MallocOverflowSecurityChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/MallocOverflowSecurityChecker.cpp
@@ -236,8 +236,8 @@
     CFGBlock *block = *it;
     for (CFGBlock::iterator bi = block->begin(), be = block->end();
          bi != be; ++bi) {
-      if (CFGStmt CS = bi->getAs<CFGStmt>()) {
-        if (const CallExpr *TheCall = dyn_cast<CallExpr>(CS.getStmt())) {
+      if (Optional<CFGStmt> CS = bi->getAs<CFGStmt>()) {
+        if (const CallExpr *TheCall = dyn_cast<CallExpr>(CS->getStmt())) {
           // Get the callee.
           const FunctionDecl *FD = TheCall->getDirectCallee();
 
diff --git a/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp b/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
index 3b4aa23..91c2ffb 100644
--- a/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
@@ -131,8 +131,8 @@
       bool foundUnreachable = false;
       for (CFGBlock::const_iterator ci = CB->begin(), ce = CB->end();
            ci != ce; ++ci) {
-        if (CFGStmt S = (*ci).getAs<CFGStmt>())
-          if (const CallExpr *CE = dyn_cast<CallExpr>(S.getStmt())) {
+        if (Optional<CFGStmt> S = (*ci).getAs<CFGStmt>())
+          if (const CallExpr *CE = dyn_cast<CallExpr>(S->getStmt())) {
             if (CE->isBuiltinCall() == Builtin::BI__builtin_unreachable) {
               foundUnreachable = true;
               break;
@@ -189,8 +189,8 @@
 // Find the Stmt* in a CFGBlock for reporting a warning
 const Stmt *UnreachableCodeChecker::getUnreachableStmt(const CFGBlock *CB) {
   for (CFGBlock::const_iterator I = CB->begin(), E = CB->end(); I != E; ++I) {
-    if (CFGStmt S = I->getAs<CFGStmt>())
-      return S.getStmt();
+    if (Optional<CFGStmt> S = I->getAs<CFGStmt>())
+      return S->getStmt();
   }
   if (const Stmt *S = CB->getTerminator())
     return S;
diff --git a/lib/StaticAnalyzer/Core/BugReporter.cpp b/lib/StaticAnalyzer/Core/BugReporter.cpp
index 9191fde..0729b5e 100644
--- a/lib/StaticAnalyzer/Core/BugReporter.cpp
+++ b/lib/StaticAnalyzer/Core/BugReporter.cpp
@@ -1523,9 +1523,9 @@
       }
 
       if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) {
-        CFGElement First = BE->getFirstElement();
-        if (CFGStmt S = First.getAs<CFGStmt>()) {
-          const Stmt *stmt = S.getStmt();
+        Optional<CFGElement> First = BE->getFirstElement();
+        if (Optional<CFGStmt> S = First ? First->getAs<CFGStmt>() : None) {
+          const Stmt *stmt = S->getStmt();
           if (IsControlFlowExpr(stmt)) {
             // Add the proper context for '&&', '||', and '?'.
             EB.addContext(stmt);
diff --git a/lib/StaticAnalyzer/Core/CallEvent.cpp b/lib/StaticAnalyzer/Core/CallEvent.cpp
index 3293515..933df48 100644
--- a/lib/StaticAnalyzer/Core/CallEvent.cpp
+++ b/lib/StaticAnalyzer/Core/CallEvent.cpp
@@ -971,11 +971,12 @@
   SVal ThisVal = State->getSVal(ThisPtr);
 
   const Stmt *Trigger;
-  if (CFGAutomaticObjDtor AutoDtor = E.getAs<CFGAutomaticObjDtor>())
-    Trigger = AutoDtor.getTriggerStmt();
+  if (Optional<CFGAutomaticObjDtor> AutoDtor = E.getAs<CFGAutomaticObjDtor>())
+    Trigger = AutoDtor->getTriggerStmt();
   else
     Trigger = Dtor->getBody();
 
   return getCXXDestructorCall(Dtor, Trigger, ThisVal.getAsRegion(),
-                              E.getAs<CFGBaseDtor>(), State, CallerCtx);
+                              E.getAs<CFGBaseDtor>().hasValue(), State,
+                              CallerCtx);
 }
diff --git a/lib/StaticAnalyzer/Core/CoreEngine.cpp b/lib/StaticAnalyzer/Core/CoreEngine.cpp
index 894365c..c61bcf7 100644
--- a/lib/StaticAnalyzer/Core/CoreEngine.cpp
+++ b/lib/StaticAnalyzer/Core/CoreEngine.cpp
@@ -331,9 +331,9 @@
   WList->setBlockCounter(Counter);
 
   // Process the entrance of the block.
-  if (CFGElement E = L.getFirstElement()) {
+  if (Optional<CFGElement> E = L.getFirstElement()) {
     NodeBuilderContext Ctx(*this, L.getBlock(), Pred);
-    SubEng.processCFGElement(E, Pred, 0, &Ctx);
+    SubEng.processCFGElement(*E, Pred, 0, &Ctx);
   }
   else
     HandleBlockExit(L.getBlock(), Pred);
diff --git a/lib/StaticAnalyzer/Core/ExprEngine.cpp b/lib/StaticAnalyzer/Core/ExprEngine.cpp
index 5d5b9b7..eb83e20 100644
--- a/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -248,8 +248,6 @@
   currBldrCtx = Ctx;
 
   switch (E.getKind()) {
-    case CFGElement::Invalid:
-      llvm_unreachable("Unexpected CFGElement kind.");
     case CFGElement::Statement:
       ProcessStmt(const_cast<Stmt*>(E.castAs<CFGStmt>().getStmt()), Pred);
       return;
@@ -1226,10 +1224,10 @@
   CFGBlock::const_reverse_iterator I = B->rbegin(), E = B->rend();
   for (; I != E; ++I) {
     CFGElement Elem = *I;
-    CFGStmt CS = Elem.getAs<CFGStmt>();
+    Optional<CFGStmt> CS = Elem.getAs<CFGStmt>();
     if (!CS)
       continue;
-    if (CS.getStmt() != Condition)
+    if (CS->getStmt() != Condition)
       break;
     return Condition;
   }
diff --git a/lib/StaticAnalyzer/Core/ExprEngineC.cpp b/lib/StaticAnalyzer/Core/ExprEngineC.cpp
index b392c43..9bc8908 100644
--- a/lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -657,8 +657,8 @@
   for (CFGBlock::const_reverse_iterator I = SrcBlock->rbegin(),
                                         E = SrcBlock->rend(); I != E; ++I) {
     CFGElement CE = *I;
-    if (CFGStmt CS = CE.getAs<CFGStmt>()) {
-      const Expr *ValEx = cast<Expr>(CS.getStmt());
+    if (Optional<CFGStmt> CS = CE.getAs<CFGStmt>()) {
+      const Expr *ValEx = cast<Expr>(CS->getStmt());
       hasValue = true;
       V = state->getSVal(ValEx, LCtx);
       break;
diff --git a/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp b/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
index 5d04340..e7d59eb 100644
--- a/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngineCXX.cpp
@@ -90,8 +90,8 @@
       CFGElement Next = (*B)[currStmtIdx+1];
 
       // Is this a constructor for a local variable?
-      if (CFGStmt StmtElem = Next.getAs<CFGStmt>()) {
-        if (const DeclStmt *DS = dyn_cast<DeclStmt>(StmtElem.getStmt())) {
+      if (Optional<CFGStmt> StmtElem = Next.getAs<CFGStmt>()) {
+        if (const DeclStmt *DS = dyn_cast<DeclStmt>(StmtElem->getStmt())) {
           if (const VarDecl *Var = dyn_cast<VarDecl>(DS->getSingleDecl())) {
             if (Var->getInit()->IgnoreImplicit() == CE) {
               QualType Ty = Var->getType();
@@ -113,8 +113,8 @@
       }
       
       // Is this a constructor for a member?
-      if (CFGInitializer InitElem = Next.getAs<CFGInitializer>()) {
-        const CXXCtorInitializer *Init = InitElem.getInitializer();
+      if (Optional<CFGInitializer> InitElem = Next.getAs<CFGInitializer>()) {
+        const CXXCtorInitializer *Init = InitElem->getInitializer();
         assert(Init->isAnyMemberInitializer());
 
         const CXXMethodDecl *CurCtor = cast<CXXMethodDecl>(LCtx->getDecl());
diff --git a/lib/StaticAnalyzer/Core/PathDiagnostic.cpp b/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
index 8c6eaec..686540b 100644
--- a/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
+++ b/lib/StaticAnalyzer/Core/PathDiagnostic.cpp
@@ -476,8 +476,6 @@
   CFGElement Source = Block[SFC->getIndex()];
 
   switch (Source.getKind()) {
-  case CFGElement::Invalid:
-    llvm_unreachable("Invalid CFGElement");
   case CFGElement::Statement:
     return PathDiagnosticLocation(Source.castAs<CFGStmt>().getStmt(),
                                   SM, CallerCtx);