Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -4312,6 +4312,8 @@
   HelpText<"Set default calling convention">, Values<"cdecl,fastcall,stdcall,vectorcall,regcall">;
 def finclude_default_header : Flag<["-"], "finclude-default-header">,
   HelpText<"Include default header file for OpenCL">;
+def fno_include_default_header : Flag<["-"], "fno-include-default-header">,
+  HelpText<"Do not include default header file for OpenCL">;
 def fdeclare_opencl_builtins : Flag<["-"], "fdeclare-opencl-builtins">,
   HelpText<"Add OpenCL builtin function declarations (experimental)">;
 def fpreserve_vec3_type : Flag<["-"], "fpreserve-vec3-type">,
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -4954,6 +4954,7 @@
   if (Args.hasArg(options::OPT_nostdinc)) {
     CmdArgs.push_back("-nostdsysteminc");
     CmdArgs.push_back("-nobuiltininc");
+    CmdArgs.push_back("-fno-include-default-header");
   } else {
     if (Args.hasArg(options::OPT_nostdlibinc))
       CmdArgs.push_back("-nostdsysteminc");
Index: clang/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- clang/lib/Frontend/CompilerInvocation.cpp
+++ clang/lib/Frontend/CompilerInvocation.cpp
@@ -2594,7 +2594,7 @@
     }
   }
 
-  Opts.IncludeDefaultHeader = Args.hasArg(OPT_finclude_default_header);
+  Opts.IncludeDefaultHeader = !Args.hasArg(OPT_fno_include_default_header);
   Opts.DeclareOpenCLBuiltins = Args.hasArg(OPT_fdeclare_opencl_builtins);
 
   llvm::Triple T(TargetOpts.Triple);
Index: clang/test/CodeGenOpenCL/amdgpu-enqueue-kernel.cl
===================================================================
--- clang/test/CodeGenOpenCL/amdgpu-enqueue-kernel.cl
+++ clang/test/CodeGenOpenCL/amdgpu-enqueue-kernel.cl
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -O0 -emit-llvm -o - -triple amdgcn | FileCheck %s --check-prefix=CHECK
+// RUN: %clang_cc1 %s -cl-std=CL2.0 -O0 -emit-llvm -fno-include-default-header -o - -triple amdgcn | FileCheck %s --check-prefix=CHECK
 
 typedef struct {int a;} ndrange_t;
 
Index: clang/test/CodeGenOpenCL/atomic-ops-libcall.cl
===================================================================
--- clang/test/CodeGenOpenCL/atomic-ops-libcall.cl
+++ clang/test/CodeGenOpenCL/atomic-ops-libcall.cl
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 < %s -cl-std=CL2.0 -triple spir64 -emit-llvm | FileCheck -check-prefix=SPIR %s
-// RUN: %clang_cc1 < %s -cl-std=CL2.0 -triple armv5e-none-linux-gnueabi -emit-llvm | FileCheck -check-prefix=ARM %s
+// RUN: %clang_cc1 < %s -cl-std=CL2.0 -triple spir64 -emit-llvm -fno-include-default-header | FileCheck -check-prefix=SPIR %s
+// RUN: %clang_cc1 < %s -cl-std=CL2.0 -triple armv5e-none-linux-gnueabi -emit-llvm -fno-include-default-header | FileCheck -check-prefix=ARM %s
 typedef enum memory_order {
   memory_order_relaxed = __ATOMIC_RELAXED,
   memory_order_acquire = __ATOMIC_ACQUIRE,
Index: clang/test/CodeGenOpenCL/atomic-ops.cl
===================================================================
--- clang/test/CodeGenOpenCL/atomic-ops.cl
+++ clang/test/CodeGenOpenCL/atomic-ops.cl
@@ -1,8 +1,8 @@
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -emit-llvm -O0 -o - -triple=amdgcn-amd-amdhsa-amdgizcl | opt -instnamer -S | FileCheck %s
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -emit-llvm -O0 -o - -triple=amdgcn-amd-amdhsa | opt -instnamer -S | FileCheck %s
 
 // Also test serialization of atomic operations here, to avoid duplicating the test.
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -emit-pch -O0 -o %t -triple=amdgcn-amd-amdhsa-amdgizcl
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -include-pch %t -O0 -triple=amdgcn-amd-amdhsa-amdgizcl -emit-llvm -o - | opt -instnamer -S | FileCheck %s
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -emit-pch -O0 -o %t -triple=amdgcn-amd-amdhsa
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -include-pch %t -O0 -triple=amdgcn-amd-amdhsa -emit-llvm -o - | opt -instnamer -S | FileCheck %s
 
 #ifndef ALREADY_INCLUDED
 #define ALREADY_INCLUDED
Index: clang/test/CodeGenOpenCL/bool_cast.cl
===================================================================
--- clang/test/CodeGenOpenCL/bool_cast.cl
+++ clang/test/CodeGenOpenCL/bool_cast.cl
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -emit-llvm -o - -O0 | FileCheck %s
+// RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -fno-include-default-header -emit-llvm -o - -O0 | FileCheck %s
 
 typedef unsigned char uchar4 __attribute((ext_vector_type(4)));
 typedef unsigned int int4 __attribute((ext_vector_type(4)));
Index: clang/test/CodeGenOpenCL/cl20-device-side-enqueue.cl
===================================================================
--- clang/test/CodeGenOpenCL/cl20-device-side-enqueue.cl
+++ clang/test/CodeGenOpenCL/cl20-device-side-enqueue.cl
@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -ffake-address-space-map -O0 -emit-llvm -o - -triple "spir-unknown-unknown" | FileCheck %s --check-prefix=COMMON --check-prefix=B32
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -ffake-address-space-map -O0 -emit-llvm -o - -triple "spir64-unknown-unknown" | FileCheck %s --check-prefix=COMMON --check-prefix=B64
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -ffake-address-space-map -O1 -emit-llvm -o - -triple "spir64-unknown-unknown" | FileCheck %s --check-prefix=CHECK-LIFETIMES
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -ffake-address-space-map -O0 -emit-llvm -o - -triple "spir-unknown-unknown" | FileCheck %s --check-prefix=COMMON --check-prefix=B32
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -ffake-address-space-map -O0 -emit-llvm -o - -triple "spir64-unknown-unknown" | FileCheck %s --check-prefix=COMMON --check-prefix=B64
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -ffake-address-space-map -O1 -emit-llvm -o - -triple "spir64-unknown-unknown" | FileCheck %s --check-prefix=CHECK-LIFETIMES
 
 #pragma OPENCL EXTENSION cl_khr_subgroups : enable
 
Index: clang/test/CodeGenOpenCL/enqueue-kernel-non-entry-block.cl
===================================================================
--- clang/test/CodeGenOpenCL/enqueue-kernel-non-entry-block.cl
+++ clang/test/CodeGenOpenCL/enqueue-kernel-non-entry-block.cl
@@ -1,7 +1,7 @@
-// RUN: %clang_cc1 -cl-std=CL2.0 -O0 -emit-llvm -o - -triple amdgcn < %s | FileCheck %s --check-prefixes=COMMON,AMDGPU
-// RUN: %clang_cc1 -cl-std=CL2.0 -O0 -emit-llvm -o - -triple "spir-unknown-unknown" < %s | FileCheck %s --check-prefixes=COMMON,SPIR32
-// RUN: %clang_cc1 -cl-std=CL2.0 -O0 -emit-llvm -o - -triple "spir64-unknown-unknown" < %s | FileCheck %s --check-prefixes=COMMON,SPIR64
-// RUN: %clang_cc1 -cl-std=CL2.0 -O0 -debug-info-kind=limited -gno-column-info -emit-llvm -o - -triple amdgcn < %s | FileCheck %s --check-prefixes=CHECK-DEBUG
+// RUN: %clang_cc1 -fno-include-default-header -cl-std=CL2.0 -O0 -emit-llvm -o - -triple amdgcn < %s | FileCheck %s --check-prefixes=COMMON,AMDGPU
+// RUN: %clang_cc1 -fno-include-default-header -cl-std=CL2.0 -O0 -emit-llvm -o - -triple "spir-unknown-unknown" < %s | FileCheck %s --check-prefixes=COMMON,SPIR32
+// RUN: %clang_cc1 -fno-include-default-header -cl-std=CL2.0 -O0 -emit-llvm -o - -triple "spir64-unknown-unknown" < %s | FileCheck %s --check-prefixes=COMMON,SPIR64
+// RUN: %clang_cc1 -fno-include-default-header -cl-std=CL2.0 -O0 -debug-info-kind=limited -gno-column-info -emit-llvm -o - -triple amdgcn < %s | FileCheck %s --check-prefixes=CHECK-DEBUG
 
 // Check that the enqueue_kernel array temporary is in the entry block to avoid
 // a dynamic alloca
Index: clang/test/CodeGenOpenCL/ext-int-shift.cl
===================================================================
--- clang/test/CodeGenOpenCL/ext-int-shift.cl
+++ clang/test/CodeGenOpenCL/ext-int-shift.cl
@@ -1,4 +1,4 @@
-// RUN: %clang -cc1 -triple x86_64-linux-pc -O3 -disable-llvm-passes %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang -cc1 -fno-include-default-header -triple x86_64-linux-pc -O3 -disable-llvm-passes %s -emit-llvm -o - | FileCheck %s
 
 void Shifts(_ExtInt(12) E, int i) {
   E << 99;
Index: clang/test/CodeGenOpenCL/fpmath.cl
===================================================================
--- clang/test/CodeGenOpenCL/fpmath.cl
+++ clang/test/CodeGenOpenCL/fpmath.cl
@@ -1,7 +1,7 @@
-// RUN: %clang_cc1 %s -emit-llvm -o - -triple spir-unknown-unknown | FileCheck --check-prefix=CHECK --check-prefix=NODIVOPT %s
-// RUN: %clang_cc1 %s -emit-llvm -o - -triple spir-unknown-unknown -cl-fp32-correctly-rounded-divide-sqrt | FileCheck --check-prefix=CHECK --check-prefix=DIVOPT %s
-// RUN: %clang_cc1 %s -emit-llvm -o - -DNOFP64 -cl-std=CL1.2 -triple r600-unknown-unknown -target-cpu r600 -pedantic | FileCheck --check-prefix=CHECK-FLT %s
-// RUN: %clang_cc1 %s -emit-llvm -o - -DFP64 -cl-std=CL1.2 -triple spir-unknown-unknown -pedantic | FileCheck --check-prefix=CHECK-DBL %s
+// RUN: %clang_cc1 %s -fno-include-default-header -emit-llvm -o - -triple spir-unknown-unknown | FileCheck --check-prefix=CHECK --check-prefix=NODIVOPT %s
+// RUN: %clang_cc1 %s -fno-include-default-header -emit-llvm -o - -triple spir-unknown-unknown -cl-fp32-correctly-rounded-divide-sqrt | FileCheck --check-prefix=CHECK --check-prefix=DIVOPT %s
+// RUN: %clang_cc1 %s -fno-include-default-header -emit-llvm -o - -DNOFP64 -cl-std=CL1.2 -triple r600-unknown-unknown -target-cpu r600 -pedantic | FileCheck --check-prefix=CHECK-FLT %s
+// RUN: %clang_cc1 %s -fno-include-default-header -emit-llvm -o - -DFP64 -cl-std=CL1.2 -triple spir-unknown-unknown -pedantic | FileCheck --check-prefix=CHECK-DBL %s
 
 typedef __attribute__(( ext_vector_type(4) )) float float4;
 
Index: clang/test/CodeGenOpenCL/half.cl
===================================================================
--- clang/test/CodeGenOpenCL/half.cl
+++ clang/test/CodeGenOpenCL/half.cl
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 %s -emit-llvm -o - -triple spir-unknown-unknown | FileCheck %s
-// RUN: %clang_cc1 %s -emit-llvm -o - -triple x86_64-pc-win32 | FileCheck %s
+// RUN: %clang_cc1 %s -fno-include-default-header -emit-llvm -o - -triple spir-unknown-unknown | FileCheck %s
+// RUN: %clang_cc1 %s -fno-include-default-header -emit-llvm -o - -triple x86_64-pc-win32 | FileCheck %s
 
 #pragma OPENCL EXTENSION cl_khr_fp16 : enable
 
Index: clang/test/CodeGenOpenCL/null_queue.cl
===================================================================
--- clang/test/CodeGenOpenCL/null_queue.cl
+++ clang/test/CodeGenOpenCL/null_queue.cl
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -O0 -cl-std=CL2.0  -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -fno-include-default-header -O0 -cl-std=CL2.0  -emit-llvm %s -o - | FileCheck %s
 extern queue_t get_default_queue();
 
 bool compare() {
Index: clang/test/CodeGenOpenCL/overload.cl
===================================================================
--- clang/test/CodeGenOpenCL/overload.cl
+++ clang/test/CodeGenOpenCL/overload.cl
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -cl-std=CL2.0 -emit-llvm -o - -triple spir-unknown-unknown %s | FileCheck %s
+// RUN: %clang_cc1 -fno-include-default-header -cl-std=CL2.0 -emit-llvm -o - -triple spir-unknown-unknown %s | FileCheck %s
 
 typedef short short4 __attribute__((ext_vector_type(4)));
 
Index: clang/test/Driver/nostdinc.cl
===================================================================
--- /dev/null
+++ clang/test/Driver/nostdinc.cl
@@ -0,0 +1,7 @@
+// RUN: %clang -S -### %s 2>&1 | FileCheck -check-prefix=DEFAULT %s
+// RUN: %clang -nostdinc -S -### %s 2>&1 | FileCheck -check-prefix=NOSTDINC %s
+
+// DEFAULT-NOT: include-default-header
+// NOSTDINC: "-fno-include-default-header"
+
+kernel void func(void);
Index: clang/test/Parser/opencl-atomics-cl20.cl
===================================================================
--- clang/test/Parser/opencl-atomics-cl20.cl
+++ clang/test/Parser/opencl-atomics-cl20.cl
@@ -1,7 +1,7 @@
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -fsyntax-only -cl-std=CL2.0 -DCL20
-// RUN: %clang_cc1 %s -triple spir64-unknown-unknown -verify -fsyntax-only -cl-std=CL2.0 -DCL20
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -fsyntax-only -cl-std=CL2.0 -DCL20 -DEXT -Wpedantic-core-features
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -pedantic -fsyntax-only
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -fsyntax-only -cl-std=CL2.0 -DCL20
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir64-unknown-unknown -verify -fsyntax-only -cl-std=CL2.0 -DCL20
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -fsyntax-only -cl-std=CL2.0 -DCL20 -DEXT -Wpedantic-core-features
 
 #ifdef EXT
 #pragma OPENCL EXTENSION cl_khr_int64_base_atomics:enable
Index: clang/test/SemaOpenCL/atomic-ops.cl
===================================================================
--- clang/test/SemaOpenCL/atomic-ops.cl
+++ clang/test/SemaOpenCL/atomic-ops.cl
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -verify -fsyntax-only -triple=spir64
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -verify -fsyntax-only -triple=amdgcn-amdhsa-amd-opencl
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -verify -fsyntax-only -triple=spir64
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -verify -fsyntax-only -triple=amdgcn-amdhsa-amd-opencl
 
 // Basic parsing/Sema tests for __opencl_atomic_*
 
Index: clang/test/SemaOpenCL/cl20-device-side-enqueue.cl
===================================================================
--- clang/test/SemaOpenCL/cl20-device-side-enqueue.cl
+++ clang/test/SemaOpenCL/cl20-device-side-enqueue.cl
@@ -1,7 +1,7 @@
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -triple "spir-unknown-unknown" -verify -pedantic -fsyntax-only -DB32 -DQUALS=
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -triple "spir-unknown-unknown" -verify -pedantic -fsyntax-only -DB32 -DQUALS="const volatile"
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -triple "spir64-unknown-unknown" -verify -pedantic -fsyntax-only -Wconversion -DWCONV -DQUALS=
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -triple "spir64-unknown-unknown" -verify -pedantic -fsyntax-only -Wconversion -DWCONV -DQUALS="const volatile"
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -triple "spir-unknown-unknown" -verify -pedantic -fsyntax-only -DB32 -DQUALS=
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -triple "spir-unknown-unknown" -verify -pedantic -fsyntax-only -DB32 -DQUALS="const volatile"
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -triple "spir64-unknown-unknown" -verify -pedantic -fsyntax-only -Wconversion -DWCONV -DQUALS=
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -triple "spir64-unknown-unknown" -verify -pedantic -fsyntax-only -Wconversion -DWCONV -DQUALS="const volatile"
 
 typedef struct {int a;} ndrange_t;
 // Diagnostic tests for different overloads of enqueue_kernel from Table 6.13.17.1 of OpenCL 2.0 Spec.
Index: clang/test/SemaOpenCL/extensions.cl
===================================================================
--- clang/test/SemaOpenCL/extensions.cl
+++ clang/test/SemaOpenCL/extensions.cl
@@ -1,33 +1,33 @@
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-std=CL1.1
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-std=CL1.2 -DFP64
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -pedantic -fsyntax-only
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-std=CL1.1
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-std=CL1.2 -DFP64
 
 // Test with a target not supporting fp64.
-// RUN: %clang_cc1 %s -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -DNOFP64 -DNOFP16
+// RUN: %clang_cc1 %s -fno-include-default-header -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -DNOFP64 -DNOFP16
 
 // Test with some extensions enabled or disabled by cmd-line args
 //
 // Target does not support fp64 and fp16 - override it
-// RUN: %clang_cc1 %s -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -cl-ext=+cl_khr_fp64,+cl_khr_fp16
+// RUN: %clang_cc1 %s -fno-include-default-header -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -cl-ext=+cl_khr_fp64,+cl_khr_fp16
 //
 // Disable or enable all extensions
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-ext=-all -DNOFP64 -DNOFP16
-// RUN: %clang_cc1 %s -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -cl-ext=+all
-// RUN: %clang_cc1 %s -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -cl-ext=+all,-cl_khr_fp64 -DNOFP64
-// RUN: %clang_cc1 %s -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -cl-ext=-all,+cl_khr_fp64 -DNOFP16
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-ext=-all -DNOFP64 -DNOFP16
+// RUN: %clang_cc1 %s -fno-include-default-header -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -cl-ext=+all
+// RUN: %clang_cc1 %s -fno-include-default-header -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -cl-ext=+all,-cl_khr_fp64 -DNOFP64
+// RUN: %clang_cc1 %s -fno-include-default-header -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -cl-ext=-all,+cl_khr_fp64 -DNOFP16
 //
 // Concatenating
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-ext=-cl_khr_fp64 -cl-ext=+cl_khr_fp64
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-ext=-cl_khr_fp64,+cl_khr_fp64
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-ext=-all -cl-ext=+cl_khr_fp64 -cl-ext=+cl_khr_fp16 -cl-ext=-cl_khr_fp64 -DNOFP64
-// RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-ext=-all -cl-ext=+cl_khr_fp64,-cl_khr_fp64,+cl_khr_fp16 -DNOFP64
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-ext=-cl_khr_fp64 -cl-ext=+cl_khr_fp64
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-ext=-cl_khr_fp64,+cl_khr_fp64
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-ext=-all -cl-ext=+cl_khr_fp64 -cl-ext=+cl_khr_fp16 -cl-ext=-cl_khr_fp64 -DNOFP64
+// RUN: %clang_cc1 %s -fno-include-default-header -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-ext=-all -cl-ext=+cl_khr_fp64,-cl_khr_fp64,+cl_khr_fp16 -DNOFP64
 
 // Test with -finclude-default-header, which includes opencl-c.h. opencl-c.h
 // disables all extensions by default, but supported core extensions for a
 // particular OpenCL version must be re-enabled (for example, cl_khr_fp64 is
 // enabled by default with -cl-std=CL2.0).
 //
-// RUN: %clang_cc1 %s -triple amdgcn-unknown-unknown -verify -pedantic -fsyntax-only -cl-std=CL2.0 -finclude-default-header
+// RUN: %clang_cc1 %s -triple amdgcn-unknown-unknown -verify -pedantic -fsyntax-only -cl-std=CL2.0
 // RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-std=clc++
 
 #ifdef _OPENCL_H_
Index: clang/test/SemaOpenCL/half.cl
===================================================================
--- clang/test/SemaOpenCL/half.cl
+++ clang/test/SemaOpenCL/half.cl
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only -Wno-unused-value -triple spir-unknown-unknown
+// RUN: %clang_cc1 %s -fno-include-default-header -verify -pedantic -fsyntax-only -Wno-unused-value -triple spir-unknown-unknown
 
 #pragma OPENCL EXTENSION cl_khr_fp16 : disable
 constant float f = 1.0h; // expected-error{{half precision constant requires cl_khr_fp16}}
Index: clang/test/SemaOpenCL/null_queue.cl
===================================================================
--- clang/test/SemaOpenCL/null_queue.cl
+++ clang/test/SemaOpenCL/null_queue.cl
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -verify -pedantic -fsyntax-only
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -verify -pedantic -fsyntax-only
 extern queue_t get_default_queue();
 
 void queue_arg(queue_t); // expected-note {{passing argument to parameter here}}
Index: clang/test/SemaOpenCL/sampler_t.cl
===================================================================
--- clang/test/SemaOpenCL/sampler_t.cl
+++ clang/test/SemaOpenCL/sampler_t.cl
@@ -1,9 +1,9 @@
-// RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only
-// RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only -DCHECK_SAMPLER_VALUE -Wspir-compat -triple amdgcn--amdhsa
-// RUN: %clang_cc1 %s -verify -pedantic -fsyntax-only -DCHECK_SAMPLER_VALUE -triple spir-unknown-unknown
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -verify -pedantic -fsyntax-only
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -verify -pedantic -fsyntax-only -DCHECK_SAMPLER_VALUE -Wspir-compat -triple amdgcn--amdhsa
-// RUN: %clang_cc1 %s -cl-std=CL2.0 -verify -pedantic -fsyntax-only -DCHECK_SAMPLER_VALUE -triple spir-unknown-unknown
+// RUN: %clang_cc1 %s -fno-include-default-header -verify -pedantic -fsyntax-only
+// RUN: %clang_cc1 %s -fno-include-default-header -verify -pedantic -fsyntax-only -DCHECK_SAMPLER_VALUE -Wspir-compat -triple amdgcn--amdhsa
+// RUN: %clang_cc1 %s -fno-include-default-header -verify -pedantic -fsyntax-only -DCHECK_SAMPLER_VALUE -triple spir-unknown-unknown
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -verify -pedantic -fsyntax-only
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -verify -pedantic -fsyntax-only -DCHECK_SAMPLER_VALUE -Wspir-compat -triple amdgcn--amdhsa
+// RUN: %clang_cc1 %s -fno-include-default-header -cl-std=CL2.0 -verify -pedantic -fsyntax-only -DCHECK_SAMPLER_VALUE -triple spir-unknown-unknown
 
 #define CLK_ADDRESS_CLAMP_TO_EDGE       2
 #define CLK_NORMALIZED_COORDS_TRUE      1
Index: clang/unittests/AST/MatchVerifier.h
===================================================================
--- clang/unittests/AST/MatchVerifier.h
+++ clang/unittests/AST/MatchVerifier.h
@@ -117,6 +117,7 @@
     FileName = "input.cc";
     break;
   case Lang_OpenCL:
+    Args.push_back("-nostdinc");
     FileName = "input.cl";
     break;
   case Lang_OBJCXX: