diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td
index 060f96118364d5cee84c08bbf9f98e53fca149bc..2bc75bd7538a9f533f0a37e3d1fecc783682c139 100644
--- a/clang/include/clang/Basic/DiagnosticDriverKinds.td
+++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -387,6 +387,11 @@ def err_drv_print_header_env_var_combination_cc1 : Error<
 def warn_O4_is_O3 : Warning<"-O4 is equivalent to -O3">, InGroup<Deprecated>;
 def warn_drv_optimization_value : Warning<"optimization level '%0' is not supported; using '%1%2' instead">,
   InGroup<InvalidCommandLineArgument>;
+def warn_ignored_gnu_functionality : Warning<"GNU functionality flag '%0' is not supported "
+  "Since -fgcc-compatible is enabled, the compiler will ignore it automatically">,
+  InGroup<IgnoredOptimizationArgument>;
+def error_ignored_gnu_functionality : Error<"GNU functionality flag '%0' is not supported, "
+  "Try -fgcc-compatible to ignore it.">;
 def warn_ignored_gcc_optimization : Warning<"optimization flag '%0' is not supported">,
   InGroup<IgnoredOptimizationArgument>;
 def warn_ignored_clang_option : Warning<"the flag '%0' has been deprecated and will be ignored">,
diff --git a/clang/include/clang/Driver/Driver.h b/clang/include/clang/Driver/Driver.h
index dcecb473b516f1f151966f46d928c27ecd721b1c..7c65d820288122c55bb31106fdcc4acde57f090e 100644
--- a/clang/include/clang/Driver/Driver.h
+++ b/clang/include/clang/Driver/Driver.h
@@ -218,7 +218,9 @@ public:
 
   std::string AutoTuneOptions;
 #endif
-
+#ifdef BUILD_FOR_OPENEULER
+  bool EnableGccCompatible = false;
+#endif
   /// The file to log CC_PRINT_PROC_STAT_FILE output to, if enabled.
   std::string CCPrintStatReportFilename;
 
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 296f9d47636a1701dc4d5adc085993d456a4833b..c6cdeecf28fe3c7ba664ac5ed368b874d1362f1e 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -274,7 +274,11 @@ def enable_trivial_var_init_zero : Flag<["-"], "enable-trivial-auto-var-init-zer
 // Group that ignores all gcc optimizations that won't be implemented
 def clang_ignored_gcc_optimization_f_Group : OptionGroup<
   "<clang_ignored_gcc_optimization_f_Group>">, Group<f_Group>, Flags<[Ignored]>;
+#ifdef BUILD_FOR_OPENEULER
+def clang_ignored_gnu_functionality_Group : OptionGroup<
+  "<clang_ignored_gnu_functionality_Group>">, Flags<[Ignored]>;
 
+#endif
 class DiagnosticOpts<string base>
   : KeyPathAndMacro<"DiagnosticOpts->", base, "DIAG_"> {}
 class LangOpts<string base>
@@ -7698,3 +7702,7 @@ def dxc_validator_path_EQ : Joined<["--"], "dxv-path=">, Group<dxc_Group>,
   HelpText<"DXIL validator installation path">;
 def dxc_disable_validation : DXCFlag<"Vd">,
   HelpText<"Disable validation">;
+#ifdef BUILD_FOR_OPENEULER
+defm canonical_system_headers_option : BooleanFFlag<"canonical-system-headers">,
+  Group<clang_ignored_gnu_functionality_Group>;
+#endif
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/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 4e5f689498d69b35aba7e843b73405bf4fab71ee..4b8c5ab8971120d65459d26923368d056b803587 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -6096,6 +6096,17 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     D.Diag(diag::warn_ignored_gcc_optimization) << A->getAsString(Args);
     A->claim();
   }
+#ifdef BUILD_FOR_OPENEULER
+  // Warn about ignored GNU functionality
+  for (const Arg &A :
+       Args.filtered(options::OPT_clang_ignored_gnu_functionality_Group)) {
+    if (Args.hasArg(options::OPT_fgcc_compatible))
+      D.Diag(diag::warn_ignored_gnu_functionality) << A->getAsString(Args);
+    else
+      D.Diag(diag::error_ignored_gnu_functionality) << A->getAsString(Args);
+    A->claim();
+  }
+#endif
 
   for (const Arg *A :
        Args.filtered(options::OPT_clang_ignored_legacy_options_Group)) {
diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index 0bd4b01ff79dbbf475697609b688144577f54456..726b605785fa7452cf536834e31e542a30be1f40 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 +1170,7 @@ void ASTFrontendAction::ExecuteAction() {
 
   if (!CI.hasSema())
     CI.createSema(getTranslationUnitKind(), CompletionConsumer);
-
+  
   ParseAST(CI.getSema(), CI.getFrontendOpts().ShowStats,
            CI.getFrontendOpts().SkipFunctionBodies);
 }