diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index c5119f79583b..a55f41647425 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1815,14 +1815,11 @@ def err_attribute_unsupported : Error<
 def err_aligned_attribute_argument_not_int : Error<
   "'aligned' attribute requires integer constant">;
 def err_alignas_attribute_wrong_decl_type : Error<
-  "'%select{alignas|_Alignas}0' attribute cannot be applied to a %select{"
-  "function parameter|variable with 'register' storage class|"
-  "'catch' variable|bit-field}1">;
+  "%0 attribute cannot be applied to a %select{function parameter|"
+  "variable with 'register' storage class|'catch' variable|bit-field}1">;
 def err_alignas_missing_on_definition : Error<
-  "'%select{alignas|_Alignas}0' must be specified on definition if it is "
-  "specified on any declaration">;
-def note_alignas_on_declaration : Note<
-  "declared with '%select{alignas|_Alignas}0' attribute here">;
+  "%0 must be specified on definition if it is specified on any declaration">;
+def note_alignas_on_declaration : Note<"declared with %0 attribute here">;
 def err_alignas_mismatch : Error<
   "redeclaration has different alignment requirement (%1 vs %0)">;
 def err_alignas_underaligned : Error<
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 493b9be11670..b89ccce832de 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -1937,9 +1937,9 @@ static bool mergeAlignedAttrs(Sema &S, NamedDecl *New, Decl *Old) {
     //   specifier, any other declaration of that object shall also
     //   have no alignment specifier.
     S.Diag(New->getLocation(), diag::err_alignas_missing_on_definition)
-      << OldAlignasAttr->isC11();
+      << OldAlignasAttr;
     S.Diag(OldAlignasAttr->getLocation(), diag::note_alignas_on_declaration)
-      << OldAlignasAttr->isC11();
+      << OldAlignasAttr;
   }
 
   bool AnyAdded = false;
@@ -2095,9 +2095,9 @@ static void checkNewAttributesAfterDef(Sema &S, Decl *New, const Decl *Old) {
         //   specifier, any other declaration of that object shall also
         //   have no alignment specifier.
         S.Diag(Def->getLocation(), diag::err_alignas_missing_on_definition)
-          << AA->isC11();
+          << AA;
         S.Diag(NewAttribute->getLocation(), diag::note_alignas_on_declaration)
-          << AA->isC11();
+          << AA;
         NewAttributes.erase(NewAttributes.begin() + I);
         --E;
         continue;
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index ff9134624025..dbbd4a16248d 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -2793,15 +2793,14 @@ void Sema::AddAlignedAttr(SourceRange AttrRange, Decl *D, Expr *E,
       if (FD->isBitField())
         DiagKind = 3;
     } else if (!isa<TagDecl>(D)) {
-      Diag(AttrLoc, diag::err_attribute_wrong_decl_type)
-        << (TmpAttr.isC11() ? "'_Alignas'" : "'alignas'")
+      Diag(AttrLoc, diag::err_attribute_wrong_decl_type) << &TmpAttr
         << (TmpAttr.isC11() ? ExpectedVariableOrField
                             : ExpectedVariableFieldOrTag);
       return;
     }
     if (DiagKind != -1) {
       Diag(AttrLoc, diag::err_alignas_attribute_wrong_decl_type)
-        << TmpAttr.isC11() << DiagKind;
+        << &TmpAttr << DiagKind;
       return;
     }
   }