diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index d23df6c..e08c5fc 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3940,16 +3940,17 @@
   "%1 %select{||||||which is not trivially copyable}0">;
 
 // Expressions.
-def ext_sizeof_function_type : Extension<
-  "invalid application of 'sizeof' to a function type">, InGroup<PointerArith>;
-def ext_sizeof_void_type : Extension<
-  "invalid application of '%select{sizeof|__alignof|vec_step}0' to a void "
+def ext_sizeof_alignof_function_type : Extension<
+  "invalid application of '%select{sizeof|alignof|vec_step}0' to a "
+  "function type">, InGroup<PointerArith>;
+def ext_sizeof_alignof_void_type : Extension<
+  "invalid application of '%select{sizeof|alignof|vec_step}0' to a void "
   "type">, InGroup<PointerArith>;
 def err_sizeof_alignof_incomplete_type : Error<
-  "invalid application of '%select{sizeof|__alignof|vec_step}0' to an "
+  "invalid application of '%select{sizeof|alignof|vec_step}0' to an "
   "incomplete type %1">;
 def err_sizeof_alignof_bitfield : Error<
-  "invalid application of '%select{sizeof|__alignof}0' to bit-field">;
+  "invalid application of '%select{sizeof|alignof}0' to bit-field">;
 def err_vecstep_non_scalar_vector_type : Error<
   "'vec_step' requires built-in scalar or vector type, %0 invalid">;
 def err_offsetof_incomplete_type : Error<
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index f52621a..bf4632c 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -3012,16 +3012,17 @@
                                            SourceRange ArgRange,
                                            UnaryExprOrTypeTrait TraitKind) {
   // C99 6.5.3.4p1:
-  if (T->isFunctionType()) {
-    // alignof(function) is allowed as an extension.
-    if (TraitKind == UETT_SizeOf)
-      S.Diag(Loc, diag::ext_sizeof_function_type) << ArgRange;
+  if (T->isFunctionType() &&
+      (TraitKind == UETT_SizeOf || TraitKind == UETT_AlignOf)) {
+    // sizeof(function)/alignof(function) is allowed as an extension.
+    S.Diag(Loc, diag::ext_sizeof_alignof_function_type)
+      << TraitKind << ArgRange;
     return false;
   }
 
   // Allow sizeof(void)/alignof(void) as an extension.
   if (T->isVoidType()) {
-    S.Diag(Loc, diag::ext_sizeof_void_type) << TraitKind << ArgRange;
+    S.Diag(Loc, diag::ext_sizeof_alignof_void_type) << TraitKind << ArgRange;
     return false;
   }
 
diff --git a/test/Sema/exprs.c b/test/Sema/exprs.c
index df3e258..2fb17e4 100644
--- a/test/Sema/exprs.c
+++ b/test/Sema/exprs.c
@@ -94,7 +94,7 @@
 struct f { int x : 4;  float y[]; };
 int test9(struct f *P) {
   int R;
-  R = __alignof(P->x);  // expected-error {{invalid application of '__alignof' to bit-field}}
+  R = __alignof(P->x);  // expected-error {{invalid application of 'alignof' to bit-field}}
   R = __alignof(P->y);   // ok.
   R = sizeof(P->x); // expected-error {{invalid application of 'sizeof' to bit-field}}
   return R;
diff --git a/test/SemaCXX/attr-cxx0x.cpp b/test/SemaCXX/attr-cxx0x.cpp
index 002800e..e9276cd 100644
--- a/test/SemaCXX/attr-cxx0x.cpp
+++ b/test/SemaCXX/attr-cxx0x.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -fcxx-exceptions -verify -std=c++11 %s
+// RUN: %clang_cc1 -fsyntax-only -fcxx-exceptions -verify -pedantic -std=c++11 %s
 
 int align_illegal alignas(3); //expected-error {{requested alignment is not a power of 2}}
 char align_big alignas(int);
@@ -43,3 +43,5 @@
 static_assert(alignof(align_class_temp_pack_type<short, int, long>) == alignof(long), "template's alignment is wrong");
 static_assert(alignof(align_class_temp_pack_expr<8, 16, 32>) == 32, "template's alignment is wrong");
 static_assert(alignof(outer<int,char>::inner<double,short>) == alignof(int) * alignof(double), "template's alignment is wrong");
+
+static_assert(alignof(int(int)) >= 1, "alignof(function) not positive"); // expected-warning{{invalid application of 'alignof' to a function type}}