diff --git a/clang/lib/Basic/Diagnostic.cpp b/clang/lib/Basic/Diagnostic.cpp
index 7a54d27ef9d8ee2d407109606c644feca7b9cdf9..76273b032d4c4512f1e390868772cada3d92bae1 100644
--- a/clang/lib/Basic/Diagnostic.cpp
+++ b/clang/lib/Basic/Diagnostic.cpp
@@ -355,13 +355,22 @@ void DiagnosticsEngine::setSeverity(diag::kind Diag, diag::Severity Map,
                                     SourceLocation L) {
   assert(Diag < diag::DIAG_UPPER_LIMIT &&
          "Can only map builtin diagnostics");
+#ifdef BUILD_FOR_OPENEULER
+  if (!(DiagOpts->GccCompatible)) {
+#endif
   assert((Diags->isBuiltinWarningOrExtension(Diag) ||
           (Map == diag::Severity::Fatal || Map == diag::Severity::Error)) &&
          "Cannot map errors into warnings!");
+#ifdef BUILD_FOR_OPENEULER
+  }
+#endif
   assert((L.isInvalid() || SourceMgr) && "No SourceMgr for valid location");
 
   // Don't allow a mapping to a warning override an error/fatal mapping.
   bool WasUpgradedFromWarning = false;
+#ifdef BUILD_FOR_OPENEULER
+  if (!(DiagOpts->GccCompatible)) {
+#endif
   if (Map == diag::Severity::Warning) {
     DiagnosticMapping &Info = GetCurDiagState()->getOrAddMapping(Diag);
     if (Info.getSeverity() == diag::Severity::Error ||
@@ -370,6 +379,9 @@ void DiagnosticsEngine::setSeverity(diag::kind Diag, diag::Severity Map,
       WasUpgradedFromWarning = true;
     }
   }
+#ifdef BUILD_FOR_OPENEULER
+  }
+#endif
   DiagnosticMapping Mapping = makeUserMapping(Map, L);
   Mapping.setUpgradedFromWarning(WasUpgradedFromWarning);
 
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index 0bd4b01ff79dbbf475697609b688144577f54456..6f684dc3c019046fee702c41c21f1c1608d6d6e5 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -31,6 +31,7 @@
 #include "clang/Parse/ParseAST.h"
 #include "clang/Sema/HLSLExternalSemaSource.h"
 #include "clang/Sema/MultiplexExternalSemaSource.h"
+#include "clang/Sema/SemaDiagnostic.h"
 #include "clang/Serialization/ASTDeserializationListener.h"
 #include "clang/Serialization/ASTReader.h"
 #include "clang/Serialization/GlobalModuleIndex.h"
@@ -1169,7 +1170,13 @@ void ASTFrontendAction::ExecuteAction() {
 
   if (!CI.hasSema())
     CI.createSema(getTranslationUnitKind(), CompletionConsumer);
-
+#ifdef BUILD_FOR_OPENEULER
+  if (CI.getLangOpts().GccCompatible) {
+    // error: ISO C++11 does not allow access declarations
+    CI.getSema().Diags.setSeverity(diag::err_access_decl,
+		                   diag::Severity::Warning, {});
+  }
+#endif
   ParseAST(CI.getSema(), CI.getFrontendOpts().ShowStats,
            CI.getFrontendOpts().SkipFunctionBodies);
 }