Index: cfe/trunk/include/clang/AST/Decl.h
===================================================================
--- cfe/trunk/include/clang/AST/Decl.h
+++ cfe/trunk/include/clang/AST/Decl.h
@@ -1954,6 +1954,7 @@
   unsigned getMinRequiredArguments() const;
 
   QualType getReturnType() const {
+    assert(getType()->getAs<FunctionType>() && "Expected a FunctionType!");
     return getType()->getAs<FunctionType>()->getReturnType();
   }
 
@@ -1964,6 +1965,7 @@
 
   /// \brief Determine the type of an expression that calls this function.
   QualType getCallResultType() const {
+    assert(getType()->getAs<FunctionType>() && "Expected a FunctionType!");
     return getType()->getAs<FunctionType>()->getCallResultType(getASTContext());
   }
 
Index: cfe/trunk/include/clang/Basic/Attr.td
===================================================================
--- cfe/trunk/include/clang/Basic/Attr.td
+++ cfe/trunk/include/clang/Basic/Attr.td
@@ -879,6 +879,8 @@
 
 def Mode : Attr {
   let Spellings = [GCC<"mode">];
+  let Subjects = SubjectList<[Var, TypedefName], ErrorDiag,
+                             "ExpectedVariableOrTypedef">;
   let Args = [IdentifierArgument<"Mode">];
   let Documentation = [Undocumented];
 }
Index: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2851,8 +2851,6 @@
   InGroup<DeprecatedAttributes>;
 def err_complex_mode_vector_type : Error<
   "type of machine mode does not support base vector types">;
-def err_attr_wrong_decl : Error<
-  "%0 attribute invalid on this declaration, requires typedef or value">;
 def warn_attribute_nonnull_no_pointers : Warning<
   "'nonnull' attribute applied to function with no pointer arguments">,
   InGroup<IgnoredAttributes>;
Index: cfe/trunk/lib/Sema/SemaDeclAttr.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaDeclAttr.cpp
+++ cfe/trunk/lib/Sema/SemaDeclAttr.cpp
@@ -3391,13 +3391,8 @@
   QualType OldTy;
   if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D))
     OldTy = TD->getUnderlyingType();
-  else if (ValueDecl *VD = dyn_cast<ValueDecl>(D))
-    OldTy = VD->getType();
-  else {
-    S.Diag(D->getLocation(), diag::err_attr_wrong_decl)
-      << Attr.getName() << Attr.getRange();
-    return;
-  }
+  else
+    OldTy = cast<VarDecl>(D)->getType();
 
   // Base type can also be a vector type (see PR17453).
   // Distinguish between base type and base element type.
@@ -3470,7 +3465,7 @@
   if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(D))
     TD->setModedTypeSourceInfo(TD->getTypeSourceInfo(), NewTy);
   else
-    cast<ValueDecl>(D)->setType(NewTy);
+    cast<VarDecl>(D)->setType(NewTy);
 
   D->addAttr(::new (S.Context)
              ModeAttr(Attr.getRange(), S.Context, Name,
Index: cfe/trunk/test/Sema/attr-mode.c
===================================================================
--- cfe/trunk/test/Sema/attr-mode.c
+++ cfe/trunk/test/Sema/attr-mode.c
@@ -24,6 +24,9 @@
 
 int **__attribute((mode(QI)))* i32;  // expected-error{{mode attribute}}
 
+__attribute__((mode(QI))) int invalid_func() { return 1; } // expected-error{{'mode' attribute only applies to variables and typedefs}}
+enum invalid_enum { A1 __attribute__((mode(QI))) }; // expected-error{{'mode' attribute only applies to variables and typedefs}}
+
 typedef _Complex double c32 __attribute((mode(SC)));
 int c32_test[sizeof(c32) == 8 ? 1 : -1];
 typedef _Complex float c64 __attribute((mode(DC)));