diff --git a/clang/include/clang/Basic/DiagnosticOptions.def b/clang/include/clang/Basic/DiagnosticOptions.def
index 7be81f6b6a9541546896ab5abccea553a721e3b3..4ad691188a69e892f3dfbd19692c53d3cc184b72 100644
--- a/clang/include/clang/Basic/DiagnosticOptions.def
+++ b/clang/include/clang/Basic/DiagnosticOptions.def
@@ -95,6 +95,8 @@ VALUE_DIAGOPT(TabStop, 32, DefaultTabStop) /// The distance between tab stops.
 /// Column limit for formatting message diagnostics, or 0 if unused.
 VALUE_DIAGOPT(MessageLength, 32, 0)
 
+DIAGOPT(GccCompatible, 1, 0) /// -fgcc_compatible
+
 #undef DIAGOPT
 #undef ENUM_DIAGOPT
 #undef VALUE_DIAGOPT
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index ad366821f3cbff1153654f2bcad21381fa14313c..ee547b38130f1c2ef82264dc0d67cecf61411fc9 100644
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -449,6 +449,8 @@ ENUM_LANGOPT(ExtendIntArgs, ExtendArgsKind, 1, ExtendArgsKind::ExtendTo32,
 
 VALUE_LANGOPT(FuchsiaAPILevel, 32, 0, "Fuchsia API level")
 
+LANGOPT(GccCompatible, 1, 0, "Enable gcc compatibility.")
+
 // This option will be removed in the future once the backend
 // supports all operations (like division or float-to-integer conversion)
 // on large _BitInts.
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 3cab37b21aaf3f4bee4daecb21bd90d3cb5cf069..cffa38d83d0e3b55740a1050cd18d49506ac634b 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -522,6 +522,12 @@ defvar std = !strconcat("LangStandard::getLangStandardForKind(", lang_std.KeyPat
 
 // Developer Driver Options
 
+def fgcc_compatible : Flag<["-"], "fgcc-compatible">, Group<f_Group>,
+  MarshallingInfoFlag<DiagnosticOpts<"GccCompatible">>, Flags<[CC1Option, NoArgumentUnused]>,
+  HelpText<"Enable gcc compatibility.">;
+def fno_gcc_compatible : Flag<["-"], "fno-gcc-compatible">, Group<f_Group>,
+  Flags<[CC1Option, NoArgumentUnused]>;
+
 def internal_Group : OptionGroup<"<clang internal options>">, Flags<[HelpHidden]>;
 def internal_driver_Group : OptionGroup<"<clang driver internal options>">,
   Group<internal_Group>, HelpText<"DRIVER OPTIONS">;
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 3704ed8586682677882acb8e1b82bfc14b1d07a5..5929f19b27593d81313e52981d060046f6d0f8a9 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4542,6 +4542,14 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   CmdArgs.push_back("-triple");
   CmdArgs.push_back(Args.MakeArgString(TripleStr));
 
+  if (Args.hasFlag(options::OPT_fgcc_compatible,
+                   options::OPT_fno_gcc_compatible, false)) {
+    CmdArgs.push_back("-Wno-error=unknown-warning-option");
+    CmdArgs.push_back("-Wno-error=unused-command-line-argument");
+    Args.AddLastArg(CmdArgs, options::OPT_fgcc_compatible,
+                    options::OPT_fno_gcc_compatible);
+  }
+
   if (const Arg *MJ = Args.getLastArg(options::OPT_MJ)) {
     DumpCompilationDatabase(C, MJ->getValue(), TripleStr, Output, Input, Args);
     Args.ClaimAllArgs(options::OPT_MJ);