Index: clang/include/clang/Basic/LangOptions.def
===================================================================
--- clang/include/clang/Basic/LangOptions.def
+++ clang/include/clang/Basic/LangOptions.def
@@ -255,6 +255,7 @@
 LANGOPT(FakeAddressSpaceMap , 1, 0, "OpenCL fake address space map")
 ENUM_LANGOPT(AddressSpaceMapMangling , AddrSpaceMapMangling, 2, ASMM_Target, "OpenCL address space map mangling mode")
 LANGOPT(IncludeDefaultHeader, 1, 0, "Include default header file for OpenCL")
+LANGOPT(GenerateOpenCLBuiltin, 1, 0, "Generate OpenCL Builtin functions using Tablegen")
 BENIGN_LANGOPT(DelayedTemplateParsing , 1, 0, "delayed template parsing")
 LANGOPT(BlocksRuntimeOptional , 1, 0, "optional blocks runtime")
 LANGOPT(
Index: clang/include/clang/Driver/CC1Options.td
===================================================================
--- clang/include/clang/Driver/CC1Options.td
+++ clang/include/clang/Driver/CC1Options.td
@@ -752,6 +752,8 @@
   HelpText<"Set default calling convention">, Values<"cdecl,fastcall,stdcall,vectorcall,regcall">;
 def finclude_default_header : Flag<["-"], "finclude-default-header">,
   HelpText<"Include the default header file for OpenCL">;
+def fgenerate_opencl_builtin: Flag<["-"], "fgenerate-opencl-builtin">,
+  HelpText<"Generate OpenCL builtin functions using Tablegen">;
 def fpreserve_vec3_type : Flag<["-"], "fpreserve-vec3-type">,
   HelpText<"Preserve 3-component vector type">;
 def fwchar_type_EQ : Joined<["-"], "fwchar-type=">,
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -2152,7 +2152,7 @@
     Opts.NativeHalfArgsAndReturns = 1;
     Opts.OpenCLCPlusPlus = Opts.CPlusPlus;
     // Include default header file for OpenCL.
-    if (Opts.IncludeDefaultHeader) {
+    if (Opts.IncludeDefaultHeader && !Opts.GenerateOpenCLBuiltin) {
       PPOpts.Includes.push_back("opencl-c.h");
     }
   }
@@ -2355,6 +2355,7 @@
   }
 
   Opts.IncludeDefaultHeader = Args.hasArg(OPT_finclude_default_header);
+  Opts.GenerateOpenCLBuiltin = Args.hasArg(OPT_fgenerate_opencl_builtin);
 
   llvm::Triple T(TargetOpts.Triple);
   CompilerInvocation::setLangDefaults(Opts, IK, T, PPOpts, LangStd);
Index: clang/lib/Sema/SemaLookup.cpp
===================================================================
--- clang/lib/Sema/SemaLookup.cpp
+++ clang/lib/Sema/SemaLookup.cpp
@@ -820,7 +820,7 @@
       }
 
       // Check if this is an OpenCL Builtin, and if so, insert the declarations.
-      if (S.getLangOpts().OpenCL) {
+      if (S.getLangOpts().OpenCL && S.getLangOpts().GenerateOpenCLBuiltin) {
         auto Index = isOpenCLBuiltin(II->getName());
         if (Index.first) {
           InsertBuiltinDeclarations(S, R, II, Index.first, Index.second);