diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index e5aca24..3def572 100644
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -2391,6 +2391,53 @@
   virtual child_iterator child_end(); 
 };
 
+
+class ParenListExpr : public Expr {
+  Stmt **Exprs;
+  unsigned NumExprs;
+  SourceLocation LParenLoc, RParenLoc;
+
+protected: 
+  virtual void DoDestroy(ASTContext& C);
+  
+public:
+  ParenListExpr(ASTContext& C, SourceLocation lparenloc, Expr **exprs, 
+                unsigned numexprs, SourceLocation rparenloc);
+
+  ~ParenListExpr() {}
+
+  /// \brief Build an empty paren list.
+  //explicit ParenListExpr(EmptyShell Empty) : Expr(ParenListExprClass, Empty) { }
+  
+  unsigned getNumExprs() const { return NumExprs; }
+  
+  const Expr* getExpr(unsigned Init) const { 
+    assert(Init < getNumExprs() && "Initializer access out of range!");
+    return cast_or_null<Expr>(Exprs[Init]);
+  }
+  
+  Expr* getExpr(unsigned Init) { 
+    assert(Init < getNumExprs() && "Initializer access out of range!");
+    return cast_or_null<Expr>(Exprs[Init]);
+  }
+
+  SourceLocation getLParenLoc() const { return LParenLoc; }
+  SourceLocation getRParenLoc() const { return RParenLoc; }
+
+  virtual SourceRange getSourceRange() const {
+    return SourceRange(LParenLoc, RParenLoc);
+  } 
+  static bool classof(const Stmt *T) {
+    return T->getStmtClass() == ParenListExprClass; 
+  }
+  static bool classof(const ParenListExpr *) { return true; }
+  
+  // Iterators
+  virtual child_iterator child_begin();
+  virtual child_iterator child_end();
+};
+
+  
 //===----------------------------------------------------------------------===//
 // Clang Extensions
 //===----------------------------------------------------------------------===//
diff --git a/include/clang/AST/StmtNodes.def b/include/clang/AST/StmtNodes.def
index 914ea27..924ad39 100644
--- a/include/clang/AST/StmtNodes.def
+++ b/include/clang/AST/StmtNodes.def
@@ -91,6 +91,7 @@
 EXPR(InitListExpr          , Expr)
 EXPR(DesignatedInitExpr    , Expr)
 EXPR(ImplicitValueInitExpr , Expr)
+EXPR(ParenListExpr         , Expr)
 EXPR(VAArgExpr             , Expr)
 
 // GNU Extensions.
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 969f23e..e723a4e 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2019,6 +2019,9 @@
   "index for __builtin_shufflevector must be less than the total number "
   "of vector elements">;
 
+def err_vector_incorrect_num_initializers : Error<
+  "%select{too many|too few}0 elements in vector initialization (expected %1 elements, have %2)">;
+def err_altivec_empty_initializer : Error<"expected initializer">;
 
 def err_stack_const_level : Error<
   "level argument for a stack address builtin must be constant">;
diff --git a/include/clang/Parse/Action.h b/include/clang/Parse/Action.h
index b2be36e..777f75e 100644
--- a/include/clang/Parse/Action.h
+++ b/include/clang/Parse/Action.h
@@ -825,6 +825,12 @@
     return move(Val);  // Default impl returns operand.
   }
 
+  virtual OwningExprResult ActOnParenListExpr(SourceLocation L, 
+                                              SourceLocation R, 
+                                              MultiExprArg Val) {
+    return ExprEmpty();
+  }
+  
   // Postfix Expressions.
   virtual OwningExprResult ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
                                                tok::TokenKind Kind,
@@ -901,11 +907,12 @@
     return ExprEmpty();
   }
 
-  virtual OwningExprResult ActOnCastExpr(SourceLocation LParenLoc, TypeTy *Ty,
-                                         SourceLocation RParenLoc, ExprArg Op) {
+  virtual OwningExprResult ActOnCastExpr(Scope *S, SourceLocation LParenLoc,
+                                         TypeTy *Ty, SourceLocation RParenLoc, 
+                                         ExprArg Op) {
     return ExprEmpty();
   }
-
+    
   virtual OwningExprResult ActOnBinOp(Scope *S, SourceLocation TokLoc,
                                       tok::TokenKind Kind,
                                       ExprArg LHS, ExprArg RHS) {
diff --git a/include/clang/Parse/Parser.h b/include/clang/Parse/Parser.h
index f2faa1c..9e785a6 100644
--- a/include/clang/Parse/Parser.h
+++ b/include/clang/Parse/Parser.h
@@ -705,9 +705,11 @@
                                               unsigned MinPrec);
   OwningExprResult ParseCastExpression(bool isUnaryExpression,
                                        bool isAddressOfOperand,
-                                       bool &NotCastExpr);
+                                       bool &NotCastExpr,
+                                       bool parseParenAsExprList);
   OwningExprResult ParseCastExpression(bool isUnaryExpression,
-                                       bool isAddressOfOperand = false);
+                                       bool isAddressOfOperand = false,
+                                       bool parseParenAsExprList = false);
   OwningExprResult ParsePostfixExpressionSuffix(OwningExprResult LHS);
   OwningExprResult ParseSizeofAlignofExpression();
   OwningExprResult ParseBuiltinPrimaryExpression();
@@ -733,6 +735,7 @@
   };
   OwningExprResult ParseParenExpression(ParenParseOption &ExprType,
                                         bool stopIfCastExpr,
+                                        bool parseAsExprList,
                                         TypeTy *&CastTy,
                                         SourceLocation &RParenLoc);
   
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 2c07de6..ce8bb51 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -1784,6 +1784,26 @@
   Expr::DoDestroy(C);
 }
 
+ParenListExpr::ParenListExpr(ASTContext& C, SourceLocation lparenloc, 
+                             Expr **exprs, unsigned nexprs,
+                             SourceLocation rparenloc)
+: Expr(ParenListExprClass, QualType(),
+       hasAnyTypeDependentArguments(exprs, nexprs),
+       hasAnyValueDependentArguments(exprs, nexprs)), 
+  NumExprs(nexprs), LParenLoc(lparenloc), RParenLoc(rparenloc) {
+  
+  Exprs = new (C) Stmt*[nexprs];
+  for (unsigned i = 0; i != nexprs; ++i)
+    Exprs[i] = exprs[i];
+}
+
+void ParenListExpr::DoDestroy(ASTContext& C) {
+  DestroyChildren(C);
+  if (Exprs) C.Deallocate(Exprs);
+  this->~ParenListExpr();
+  C.Deallocate(this);
+}
+
 //===----------------------------------------------------------------------===//
 //  ExprIterator.
 //===----------------------------------------------------------------------===//
@@ -1988,6 +2008,14 @@
   return child_iterator(); 
 }
 
+// ParenListExpr
+Stmt::child_iterator ParenListExpr::child_begin() {
+  return &Exprs[0];
+}
+Stmt::child_iterator ParenListExpr::child_end() {
+  return &Exprs[0]+NumExprs;
+}
+
 // ObjCStringLiteral
 Stmt::child_iterator ObjCStringLiteral::child_begin() { 
   return &String;
diff --git a/lib/AST/StmtPrinter.cpp b/lib/AST/StmtPrinter.cpp
index a5b0df8..a2c0497 100644
--- a/lib/AST/StmtPrinter.cpp
+++ b/lib/AST/StmtPrinter.cpp
@@ -850,6 +850,15 @@
   OS << " }";
 }
 
+void StmtPrinter::VisitParenListExpr(ParenListExpr* Node) {
+  OS << "( ";
+  for (unsigned i = 0, e = Node->getNumExprs(); i != e; ++i) {
+    if (i) OS << ", ";
+    PrintExpr(Node->getExpr(i));
+  }
+  OS << " )";
+}
+
 void StmtPrinter::VisitDesignatedInitExpr(DesignatedInitExpr *Node) {
   for (DesignatedInitExpr::designators_iterator D = Node->designators_begin(),
                       DEnd = Node->designators_end();
diff --git a/lib/AST/StmtProfile.cpp b/lib/AST/StmtProfile.cpp
index d0f02ae..5d9b8bc 100644
--- a/lib/AST/StmtProfile.cpp
+++ b/lib/AST/StmtProfile.cpp
@@ -245,6 +245,10 @@
   VisitExpr(S);
 }
 
+void StmtProfiler::VisitParenListExpr(ParenListExpr *S) {
+  VisitExpr(S);
+}
+
 void StmtProfiler::VisitUnaryOperator(UnaryOperator *S) {
   VisitExpr(S);
   ID.AddInteger(S->getOpcode());
diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index 0eb21c9..e761e9f 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -475,7 +475,7 @@
   }
   
   // A scalar can be splatted to an extended vector of the same element type
-  if (DstType->isExtVectorType() && !isa<VectorType>(SrcType)) {
+  if (DstType->isExtVectorType() && !SrcType->isVectorType()) {
     // Cast the scalar to element type
     QualType EltTy = DstType->getAsExtVectorType()->getElementType();
     llvm::Value *Elt = EmitScalarConversion(Src, SrcType, EltTy);
diff --git a/lib/Frontend/PrintParserCallbacks.cpp b/lib/Frontend/PrintParserCallbacks.cpp
index c933a2f..2101a85 100644
--- a/lib/Frontend/PrintParserCallbacks.cpp
+++ b/lib/Frontend/PrintParserCallbacks.cpp
@@ -574,8 +574,9 @@
       Out << __FUNCTION__ << "\n";
       return ExprEmpty();
     }
-    virtual OwningExprResult ActOnCastExpr(SourceLocation LParenLoc, TypeTy *Ty,
-                                           SourceLocation RParenLoc,ExprArg Op){
+    virtual OwningExprResult ActOnCastExpr(Scope *S, SourceLocation LParenLoc, 
+                                           TypeTy *Ty, SourceLocation RParenLoc,
+                                           ExprArg Op) {
       Out << __FUNCTION__ << "\n";
       return ExprEmpty();
     }
diff --git a/lib/Parse/ParseExpr.cpp b/lib/Parse/ParseExpr.cpp
index 62bd9ae..6e7deef 100644
--- a/lib/Parse/ParseExpr.cpp
+++ b/lib/Parse/ParseExpr.cpp
@@ -407,11 +407,13 @@
 /// due to member pointers.
 ///
 Parser::OwningExprResult Parser::ParseCastExpression(bool isUnaryExpression,
-                                                     bool isAddressOfOperand) {
+                                                     bool isAddressOfOperand,
+                                                     bool parseParenAsExprList){
   bool NotCastExpr;
   OwningExprResult Res = ParseCastExpression(isUnaryExpression,
                                              isAddressOfOperand,
-                                             NotCastExpr);
+                                             NotCastExpr,
+                                             parseParenAsExprList);
   if (NotCastExpr)
     Diag(Tok, diag::err_expected_expression);
   return move(Res);
@@ -530,7 +532,8 @@
 ///
 Parser::OwningExprResult Parser::ParseCastExpression(bool isUnaryExpression,
                                                      bool isAddressOfOperand,
-                                                     bool &NotCastExpr) {
+                                                     bool &NotCastExpr,
+                                                     bool parseParenAsExprList){
   OwningExprResult Res(Actions);
   tok::TokenKind SavedKind = Tok.getKind();
   NotCastExpr = false;
@@ -555,7 +558,7 @@
     SourceLocation LParenLoc = Tok.getLocation();
     SourceLocation RParenLoc;
     Res = ParseParenExpression(ParenExprType, false/*stopIfCastExr*/,
-                               CastTy, RParenLoc);
+                               parseParenAsExprList, CastTy, RParenLoc);
     if (Res.isInvalid()) return move(Res);
     
     switch (ParenExprType) {
@@ -1021,7 +1024,7 @@
     // operands.
     EnterExpressionEvaluationContext Unevaluated(Actions,
                                                  Action::Unevaluated);
-    Operand = ParseParenExpression(ExprType, true/*stopIfCastExpr*/,
+    Operand = ParseParenExpression(ExprType, true/*stopIfCastExpr*/, false,
                                    CastTy, RParenLoc);
     CastRange = SourceRange(LParenLoc, RParenLoc);
 
@@ -1278,7 +1281,8 @@
 ///
 Parser::OwningExprResult
 Parser::ParseParenExpression(ParenParseOption &ExprType, bool stopIfCastExpr,
-                             TypeTy *&CastTy, SourceLocation &RParenLoc) {
+                             bool parseAsExprList, TypeTy *&CastTy, 
+                             SourceLocation &RParenLoc) {
   assert(Tok.is(tok::l_paren) && "Not a paren expr!");
   GreaterThanIsOperatorScope G(GreaterThanIsOperator, true);
   SourceLocation OpenLoc = ConsumeParen();
@@ -1338,14 +1342,25 @@
 
       // Parse the cast-expression that follows it next.
       // TODO: For cast expression with CastTy.
-      Result = ParseCastExpression(false);
+      Result = ParseCastExpression(false, false, true);
       if (!Result.isInvalid())
-        Result = Actions.ActOnCastExpr(OpenLoc, CastTy, RParenLoc,move(Result));
+        Result = Actions.ActOnCastExpr(CurScope, OpenLoc, CastTy, RParenLoc,
+                                       move(Result));
       return move(Result);
     }
 
     Diag(Tok, diag::err_expected_lbrace_in_compound_literal);
     return ExprError();
+  } else if (parseAsExprList) {
+    // Parse the expression-list.
+    ExprVector ArgExprs(Actions);
+    CommaLocsTy CommaLocs;
+
+    if (!ParseExpressionList(ArgExprs, CommaLocs)) {
+      ExprType = SimpleExpr;
+      Result = Actions.ActOnParenListExpr(OpenLoc, Tok.getLocation(), 
+                                          move_arg(ArgExprs));
+    }
   } else {
     Result = ParseExpression();
     ExprType = SimpleExpr;
diff --git a/lib/Parse/ParseExprCXX.cpp b/lib/Parse/ParseExprCXX.cpp
index 91b4d4d..46526e4 100644
--- a/lib/Parse/ParseExprCXX.cpp
+++ b/lib/Parse/ParseExprCXX.cpp
@@ -1154,7 +1154,7 @@
       // will be consumed.
       Result = ParseCastExpression(false/*isUnaryExpression*/,
                                    false/*isAddressofOperand*/,
-                                   NotCastExpr);
+                                   NotCastExpr, false);
     }
 
     // If we parsed a cast-expression, it's really a type-id, otherwise it's
@@ -1196,7 +1196,8 @@
 
     // Result is what ParseCastExpression returned earlier.
     if (!Result.isInvalid())
-      Result = Actions.ActOnCastExpr(LParenLoc, CastTy, RParenLoc,move(Result));
+      Result = Actions.ActOnCastExpr(CurScope, LParenLoc, CastTy, RParenLoc, 
+                                     move(Result));
     return move(Result);
   }
   
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index b237ac3..b35fe67 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -50,6 +50,7 @@
   class Stmt;
   class Expr;
   class InitListExpr;
+  class ParenListExpr;
   class DesignatedInitExpr;
   class CallExpr;
   class DeclRefExpr;
@@ -1484,7 +1485,10 @@
   virtual OwningExprResult ActOnCharacterConstant(const Token &);
   virtual OwningExprResult ActOnParenExpr(SourceLocation L, SourceLocation R,
                                           ExprArg Val);
-
+  virtual OwningExprResult ActOnParenListExpr(SourceLocation L,
+                                              SourceLocation R,
+                                              MultiExprArg Val);
+  
   /// ActOnStringLiteral - The specified tokens were lexed as pasted string
   /// fragments (e.g. "foo" "bar" L"baz").
   virtual OwningExprResult ActOnStringLiteral(const Token *Toks,
@@ -1545,8 +1549,14 @@
                                          SourceLocation *CommaLocs,
                                          SourceLocation RParenLoc);
 
-  virtual OwningExprResult ActOnCastExpr(SourceLocation LParenLoc, TypeTy *Ty,
-                                         SourceLocation RParenLoc, ExprArg Op);
+  virtual OwningExprResult ActOnCastExpr(Scope *S, SourceLocation LParenLoc,
+                                         TypeTy *Ty, SourceLocation RParenLoc,
+                                         ExprArg Op);
+  
+  OwningExprResult MaybeConvertParenListExprToParenExpr(Scope *S, ExprArg ME);
+  OwningExprResult ActOnCastOfParenListExpr(Scope *S, SourceLocation LParenLoc,
+                                            SourceLocation RParenLoc, ExprArg E,
+                                            QualType Ty);
 
   virtual OwningExprResult ActOnCompoundLiteral(SourceLocation LParenLoc,
                                                 TypeTy *Ty,
diff --git a/lib/Sema/SemaCXXScopeSpec.cpp b/lib/Sema/SemaCXXScopeSpec.cpp
index e1cba36..977aa0f 100644
--- a/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/lib/Sema/SemaCXXScopeSpec.cpp
@@ -341,6 +341,9 @@
 Action::OwningExprResult
 Sema::ActOnCXXEnterMemberScope(Scope *S, CXXScopeSpec &SS, ExprArg Base,
                                tok::TokenKind OpKind) {
+  // Since this might be a postfix expression, get rid of ParenListExprs.
+  Base = MaybeConvertParenListExprToParenExpr(S, move(Base));
+
   Expr *BaseExpr = (Expr*)Base.get();
   assert(BaseExpr && "no record expansion");
 
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index f00ab54..e9b1dd4 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -1620,6 +1620,8 @@
 Action::OwningExprResult
 Sema::ActOnPostfixUnaryOp(Scope *S, SourceLocation OpLoc,
                           tok::TokenKind Kind, ExprArg Input) {
+  // Since this might be a postfix expression, get rid of ParenListExprs.
+  Input = MaybeConvertParenListExprToParenExpr(S, move(Input));
   Expr *Arg = (Expr *)Input.get();
 
   UnaryOperator::Opcode Opc;
@@ -1738,9 +1740,12 @@
 Action::OwningExprResult
 Sema::ActOnArraySubscriptExpr(Scope *S, ExprArg Base, SourceLocation LLoc,
                               ExprArg Idx, SourceLocation RLoc) {
+  // Since this might be a postfix expression, get rid of ParenListExprs.
+  Base = MaybeConvertParenListExprToParenExpr(S, move(Base));
+
   Expr *LHSExp = static_cast<Expr*>(Base.get()),
        *RHSExp = static_cast<Expr*>(Idx.get());
-
+  
   if (getLangOptions().CPlusPlus &&
       (LHSExp->isTypeDependent() || RHSExp->isTypeDependent())) {
     Base.release();
@@ -1918,7 +1923,8 @@
        << LHSExp->getSourceRange() << RHSExp->getSourceRange());
   }
   // C99 6.5.2.1p1
-  if (!IndexExpr->getType()->isIntegerType() && !IndexExpr->isTypeDependent())
+  if (!(IndexExpr->getType()->isIntegerType() &&
+        IndexExpr->getType()->isScalarType()) && !IndexExpr->isTypeDependent())
     return ExprError(Diag(LLoc, diag::err_typecheck_subscript_not_integer)
                      << IndexExpr->getSourceRange());
 
@@ -2111,9 +2117,12 @@
   if (SS && SS->isInvalid())
     return ExprError();
 
+  // Since this might be a postfix expression, get rid of ParenListExprs.
+  Base = MaybeConvertParenListExprToParenExpr(S, move(Base));
+
   Expr *BaseExpr = Base.takeAs<Expr>();
   assert(BaseExpr && "no record expression");
-
+  
   // Perform default conversions.
   DefaultFunctionArrayConversion(BaseExpr);
 
@@ -2683,13 +2692,17 @@
                     MultiExprArg args,
                     SourceLocation *CommaLocs, SourceLocation RParenLoc) {
   unsigned NumArgs = args.size();
+
+  // Since this might be a postfix expression, get rid of ParenListExprs.
+  fn = MaybeConvertParenListExprToParenExpr(S, move(fn));
+  
   Expr *Fn = fn.takeAs<Expr>();
   Expr **Args = reinterpret_cast<Expr**>(args.release());
   assert(Fn && "no function call expression");
   FunctionDecl *FDecl = NULL;
   NamedDecl *NDecl = NULL;
   DeclarationName UnqualifiedName;
-
+  
   if (getLangOptions().CPlusPlus) {
     // Determine whether this is a dependent call inside a C++ template,
     // in which case we won't do any semantic analysis now.
@@ -3090,24 +3103,92 @@
 }
 
 Action::OwningExprResult
-Sema::ActOnCastExpr(SourceLocation LParenLoc, TypeTy *Ty,
+Sema::ActOnCastExpr(Scope *S, SourceLocation LParenLoc, TypeTy *Ty,
                     SourceLocation RParenLoc, ExprArg Op) {
   CastExpr::CastKind Kind = CastExpr::CK_Unknown;
   
   assert((Ty != 0) && (Op.get() != 0) &&
          "ActOnCastExpr(): missing type or expr");
 
-  Expr *castExpr = Op.takeAs<Expr>();
+  Expr *castExpr = (Expr *)Op.get();
   QualType castType = QualType::getFromOpaquePtr(Ty);
+  
+  // If the Expr being casted is a ParenListExpr, handle it specially.
+  if (isa<ParenListExpr>(castExpr))
+    return ActOnCastOfParenListExpr(S, LParenLoc, RParenLoc, move(Op),castType);
 
   if (CheckCastTypes(SourceRange(LParenLoc, RParenLoc), castType, castExpr, 
                      Kind))
     return ExprError();
+  
+  Op.release();
   return Owned(new (Context) CStyleCastExpr(castType.getNonReferenceType(),
                                             Kind, castExpr, castType, 
                                             LParenLoc, RParenLoc));
 }
 
+/// This is not an AltiVec-style cast, so turn the ParenListExpr into a sequence
+/// of comma binary operators.
+Action::OwningExprResult
+Sema::MaybeConvertParenListExprToParenExpr(Scope *S, ExprArg EA) {
+  Expr *expr = EA.takeAs<Expr>();
+  ParenListExpr *E = dyn_cast<ParenListExpr>(expr);
+  if (!E)
+    return Owned(expr);
+  
+  OwningExprResult Result(*this, E->getExpr(0));
+  
+  for (unsigned i = 1, e = E->getNumExprs(); i != e && !Result.isInvalid(); ++i)
+    Result = ActOnBinOp(S, E->getExprLoc(), tok::comma, move(Result),
+                        Owned(E->getExpr(i)));
+  
+  return ActOnParenExpr(E->getLParenLoc(), E->getRParenLoc(), move(Result));
+}
+
+Action::OwningExprResult
+Sema::ActOnCastOfParenListExpr(Scope *S, SourceLocation LParenLoc,
+                               SourceLocation RParenLoc, ExprArg Op,
+                               QualType Ty) {
+  ParenListExpr *PE = (ParenListExpr *)Op.get();
+  
+  // If this is an altivec initializer, '(' type ')' '(' init, ..., init ')' 
+  // then handle it as such.
+  if (getLangOptions().AltiVec && Ty->isVectorType()) {
+    if (PE->getNumExprs() == 0) {
+      Diag(PE->getExprLoc(), diag::err_altivec_empty_initializer);
+      return ExprError();
+    }
+
+    llvm::SmallVector<Expr *, 8> initExprs;
+    for (unsigned i = 0, e = PE->getNumExprs(); i != e; ++i)
+      initExprs.push_back(PE->getExpr(i));
+
+    // FIXME: This means that pretty-printing the final AST will produce curly
+    // braces instead of the original commas.
+    Op.release();
+    InitListExpr *E = new (Context) InitListExpr(LParenLoc, &initExprs[0], 
+                                                 initExprs.size(), RParenLoc);
+    E->setType(Ty);
+    return ActOnCompoundLiteral(LParenLoc, Ty.getAsOpaquePtr(), RParenLoc, 
+                                Owned(E));
+  } else {
+    // This is not an AltiVec-style cast, so turn the ParenListExpr into a 
+    // sequence of BinOp comma operators.
+    Op = MaybeConvertParenListExprToParenExpr(S, move(Op));
+    return ActOnCastExpr(S, LParenLoc, Ty.getAsOpaquePtr(), RParenLoc,move(Op));
+  }
+}
+
+Action::OwningExprResult Sema::ActOnParenListExpr(SourceLocation L,
+                                                  SourceLocation R,
+                                                  MultiExprArg Val) {
+  unsigned nexprs = Val.size();
+  Expr **exprs = reinterpret_cast<Expr**>(Val.release());
+  assert((exprs != 0) && "ActOnParenListExpr() missing expr list");
+  Expr *expr = new (Context) ParenListExpr(Context, L, exprs, nexprs, R);
+  return Owned(expr);
+}
+
 /// Note that lhs is not null here, even if this is the gnu "x ?: y" extension.
 /// In that case, lhs = cond.
 /// C99 6.5.15
@@ -3132,6 +3213,8 @@
   }
 
   // Now check the two expressions.
+  if (LHSTy->isVectorType() || RHSTy->isVectorType())
+    return CheckVectorOperands(QuestionLoc, LHS, RHS);
 
   // If both operands have arithmetic type, do the usual arithmetic conversions
   // to find a common type: C99 6.5.15p3,5.
diff --git a/lib/Sema/SemaInit.cpp b/lib/Sema/SemaInit.cpp
index 2911382..1e564ce 100644
--- a/lib/Sema/SemaInit.cpp
+++ b/lib/Sema/SemaInit.cpp
@@ -805,16 +805,47 @@
                                       unsigned &StructuredIndex) {
   if (Index < IList->getNumInits()) {
     const VectorType *VT = DeclType->getAsVectorType();
-    int maxElements = VT->getNumElements();
+    unsigned maxElements = VT->getNumElements();
+    unsigned numEltsInit = 0;
     QualType elementType = VT->getElementType();
     
-    for (int i = 0; i < maxElements; ++i) {
-      // Don't attempt to go past the end of the init list
-      if (Index >= IList->getNumInits())
-        break;
-      CheckSubElementType(IList, elementType, Index,
-                          StructuredList, StructuredIndex);
+    if (!SemaRef.getLangOptions().OpenCL) {
+      for (unsigned i = 0; i < maxElements; ++i, ++numEltsInit) {
+        // Don't attempt to go past the end of the init list
+        if (Index >= IList->getNumInits())
+          break;
+        CheckSubElementType(IList, elementType, Index,
+                            StructuredList, StructuredIndex);
+      }
+    } else {
+      // OpenCL initializers allows vectors to be constructed from vectors.
+      for (unsigned i = 0; i < maxElements; ++i) {
+        // Don't attempt to go past the end of the init list
+        if (Index >= IList->getNumInits())
+          break;
+        QualType IType = IList->getInit(Index)->getType();
+        if (!IType->isVectorType()) {
+          CheckSubElementType(IList, elementType, Index,
+                              StructuredList, StructuredIndex);
+          ++numEltsInit;
+        } else {
+          const VectorType *IVT = IType->getAsVectorType();
+          unsigned numIElts = IVT->getNumElements();
+          QualType VecType = SemaRef.Context.getExtVectorType(elementType,
+                                                              numIElts);
+          CheckSubElementType(IList, VecType, Index,
+                              StructuredList, StructuredIndex);
+          numEltsInit += numIElts;
+        }
+      }
     }
+    
+    // OpenCL & AltiVec require all elements to be initialized.
+    if (numEltsInit != maxElements)
+      if (SemaRef.getLangOptions().OpenCL || SemaRef.getLangOptions().AltiVec)
+        SemaRef.Diag(IList->getSourceRange().getBegin(),
+                     diag::err_vector_incorrect_num_initializers)
+          << (numEltsInit < maxElements) << maxElements << numEltsInit;
   }
 }
 
diff --git a/lib/Sema/SemaTemplateInstantiateExpr.cpp b/lib/Sema/SemaTemplateInstantiateExpr.cpp
index 186c98c..7a09210 100644
--- a/lib/Sema/SemaTemplateInstantiateExpr.cpp
+++ b/lib/Sema/SemaTemplateInstantiateExpr.cpp
@@ -639,6 +639,20 @@
 }
 
 Sema::OwningExprResult 
+TemplateExprInstantiator::VisitParenListExpr(ParenListExpr *E) {
+  ASTOwningVector<&ActionBase::DeleteExpr, 4> Inits(SemaRef);
+  for (unsigned I = 0, N = E->getNumExprs(); I != N; ++I) {
+    OwningExprResult Init = Visit(E->getExpr(I));
+    if (Init.isInvalid())
+      return SemaRef.ExprError();
+    Inits.push_back(Init.takeAs<Expr>());
+  }
+
+  return SemaRef.ActOnParenListExpr(E->getLParenLoc(), E->getRParenLoc(),
+                                    move_arg(Inits));
+}
+
+Sema::OwningExprResult 
 TemplateExprInstantiator::VisitDesignatedInitExpr(DesignatedInitExpr *E) {
   Designation Desig;
 
@@ -886,7 +900,7 @@
   if (SubExpr.isInvalid())
     return SemaRef.ExprError();
   
-  return SemaRef.ActOnCastExpr(E->getLParenLoc(), 
+  return SemaRef.ActOnCastExpr(/*Scope=*/0, E->getLParenLoc(), 
                                ExplicitTy.getAsOpaquePtr(),
                                E->getRParenLoc(),
                                move(SubExpr));
diff --git a/test/Sema/altivec-init.c b/test/Sema/altivec-init.c
new file mode 100644
index 0000000..6185186
--- /dev/null
+++ b/test/Sema/altivec-init.c
@@ -0,0 +1,16 @@
+// RUN: clang-cc %s -faltivec -verify -pedantic -fsyntax-only -fblocks=0
+
+typedef int v4 __attribute((vector_size(16)));
+typedef short v8 __attribute((vector_size(16)));
+
+v8 foo(void) { 
+  v8 a;
+  v4 b;
+  a = (v8){4, 2}; // expected-error {{too few elements in vector initialization (expected 8 elements, have 2)}}
+  b = (v4)(5, 6, 7, 8, 9); // expected-warning {{excess elements in vector initializer}}
+  b = (v4)(5, 6, 8, 8.0f);
+  return (v8){0, 1, 2, 3, 1, 2, 3, 4};
+
+  // FIXME: test that (type)(fn)(args) still works with -faltivec
+  // FIXME: test that c++ overloaded commas still work -faltivec
+}
diff --git a/tools/clang-cc/clang-cc.cpp b/tools/clang-cc/clang-cc.cpp
index e16a91d..1e4dc81 100644
--- a/tools/clang-cc/clang-cc.cpp
+++ b/tools/clang-cc/clang-cc.cpp
@@ -387,6 +387,10 @@
                  llvm::cl::init(false));
 
 static llvm::cl::opt<bool>
+AltiVec("faltivec", llvm::cl::desc("Enable AltiVec vector initializer syntax"),
+                    llvm::cl::init(false));
+
+static llvm::cl::opt<bool>
 ObjCSenderDispatch("fobjc-sender-dependent-dispatch",
 				 llvm::cl::desc("Enable sender-dependent dispatch for"
 					 "Objective-C messages"), llvm::cl::init(false));
@@ -502,6 +506,9 @@
   if (ObjCEnableGCBitmapPrint)
     Options.ObjCGCBitmapPrint = 1;
   
+  if (AltiVec)
+    Options.AltiVec = 1;
+  
   Options.setVisibilityMode(SymbolVisibility);
   Options.OverflowChecking = OverflowChecking;
 }