diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -5208,11 +5208,9 @@
   NormalizedValues<["DCC_CDecl", "DCC_FastCall", "DCC_StdCall", "DCC_VectorCall", "DCC_RegCall"]>,
   MarshallingInfoString<LangOpts<"DefaultCallingConv">, "DCC_None">, AutoNormalizeEnum;
 def finclude_default_header : Flag<["-"], "finclude-default-header">,
-  HelpText<"Include default header file for OpenCL">,
-  MarshallingInfoFlag<LangOpts<"IncludeDefaultHeader">>;
+  HelpText<"Include default header file for OpenCL">;
 def fdeclare_opencl_builtins : Flag<["-"], "fdeclare-opencl-builtins">,
-  HelpText<"Add OpenCL builtin function declarations (experimental)">,
-  MarshallingInfoFlag<LangOpts<"DeclareOpenCLBuiltins">>;
+  HelpText<"Add OpenCL builtin function declarations (experimental)">;
 def fpreserve_vec3_type : Flag<["-"], "fpreserve-vec3-type">,
   HelpText<"Preserve 3-component vector type">,
   MarshallingInfoFlag<CodeGenOpts<"PreserveVec3Type">>;
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2137,6 +2137,20 @@
   llvm_unreachable("unknown input language");
 }
 
+static std::string GetOptName(llvm::opt::OptSpecifier OptSpecifier) {
+  static const OptTable &OptTable = getDriverOptTable();
+  return OptTable.getOption(OptSpecifier).getPrefixedName();
+}
+
+static void GenerateLangArgs(const LangOptions &Opts,
+                             SmallVectorImpl<const char *> &Args,
+                             CompilerInvocation::StringAllocator SA) {
+  if (Opts.IncludeDefaultHeader)
+    Args.push_back(SA(GetOptName(OPT_finclude_default_header)));
+  if (Opts.DeclareOpenCLBuiltins)
+    Args.push_back(SA(GetOptName(OPT_fdeclare_opencl_builtins)));
+}
+
 static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
                           const llvm::Triple &T,
                           std::vector<std::string> &Includes,
@@ -2212,6 +2226,10 @@
 
   Opts.SYCLIsDevice = Opts.SYCL && Args.hasArg(options::OPT_fsycl_is_device);
 
+  // These need to be parsed now. They are used to set OpenCL defaults.
+  Opts.IncludeDefaultHeader = Args.hasArg(OPT_finclude_default_header);
+  Opts.DeclareOpenCLBuiltins = Args.hasArg(OPT_fdeclare_opencl_builtins);
+
   CompilerInvocation::setLangDefaults(Opts, IK, T, Includes, LangStd);
 
   // -cl-strict-aliasing needs to emit diagnostic in the case where CL > 1.0.
@@ -3163,6 +3181,8 @@
 #undef DIAG_OPTION_WITH_MARSHALLING
 #undef OPTION_WITH_MARSHALLING
 #undef GENERATE_OPTION_WITH_MARSHALLING
+
+  GenerateLangArgs(*LangOpts, Args, SA);
 }
 
 IntrusiveRefCntPtr<llvm::vfs::FileSystem>