diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10023,6 +10023,9 @@
   "invalid prototype, variadic arguments are not allowed in OpenCL">;
 def err_opencl_requires_extension : Error<
   "use of %select{type|declaration}0 %1 requires %2 support">;
+def ext_opencl_double_without_pragma : Extension<
+  "Clang permits use of type 'double' regardless pragma if 'cl_khr_fp64' is"
+  " supported">;
 def warn_opencl_generic_address_space_arg : Warning<
   "passing non-generic address space pointer to %0"
   " may cause dynamic conversion affecting performance">,
diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -366,7 +366,6 @@
             "cl_khr_int64_base_atomics cl_khr_int64_extended_atomics");
     }
 
-    setOpenCLExtensionForType(Context.DoubleTy, "cl_khr_fp64");
 
 #define EXT_OPAQUE_TYPE(ExtType, Id, Ext)                                      \
   if (getOpenCLOptions().isSupported(#Ext, getLangOpts())) {                   \
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -1524,6 +1524,13 @@
     break;
   case DeclSpec::TST_float:   Result = Context.FloatTy; break;
   case DeclSpec::TST_double:
+    if (S.getLangOpts().OpenCL) {
+      if (!S.getOpenCLOptions().isSupported("cl_khr_fp64", S.getLangOpts()))
+        S.Diag(DS.getTypeSpecTypeLoc(), diag::err_opencl_requires_extension)
+          << 0 << Context.DoubleTy << "cl_khr_fp64";
+      else if (!S.getOpenCLOptions().isAvailableOption("cl_khr_fp64", S.getLangOpts()))
+        S.Diag(DS.getTypeSpecTypeLoc(), diag::ext_opencl_double_without_pragma);
+    }
     if (DS.getTypeSpecWidth() == TypeSpecifierWidth::Long)
       Result = Context.LongDoubleTy;
     else
diff --git a/clang/test/Misc/warning-flags.c b/clang/test/Misc/warning-flags.c
--- a/clang/test/Misc/warning-flags.c
+++ b/clang/test/Misc/warning-flags.c
@@ -91,4 +91,4 @@
 
 The list of warnings in -Wpedantic should NEVER grow.
 
-CHECK: Number in -Wpedantic (not covered by other -W flags): 26
+CHECK: Number in -Wpedantic (not covered by other -W flags): 27
diff --git a/clang/test/SemaOpenCL/extensions.cl b/clang/test/SemaOpenCL/extensions.cl
--- a/clang/test/SemaOpenCL/extensions.cl
+++ b/clang/test/SemaOpenCL/extensions.cl
@@ -1,5 +1,6 @@
 // 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 -fsyntax-only -cl-std=CL1.1 -DNOPEDANTIC
 // RUN: %clang_cc1 %s -triple spir-unknown-unknown -verify -pedantic -fsyntax-only -cl-std=CL1.2 -DFP64
 
 // Test with a target not supporting fp64.
@@ -43,8 +44,20 @@
 #endif
 
 #if (defined(__OPENCL_C_VERSION__) && __OPENCL_C_VERSION__ < 120)
-void f1(double da) { // expected-error {{type 'double' requires cl_khr_fp64 support}}
-  double d; // expected-error {{type 'double' requires cl_khr_fp64 support}}
+void f1(double da) {
+#ifdef NOFP64
+// expected-error@-2 {{type 'double' requires cl_khr_fp64 support}}
+#elif !defined(NOPEDANTIC)
+// expected-warning@-4{{Clang permits use of type 'double' regardless pragma if 'cl_khr_fp64' is supported}}
+#endif
+  double d;
+#ifdef NOFP64
+// expected-error@-2 {{type 'double' requires cl_khr_fp64 support}}
+#elif !defined(NOPEDANTIC)
+// expected-warning@-4{{Clang permits use of type 'double' regardless pragma if 'cl_khr_fp64' is supported}}
+#endif
+  // FIXME: this diagnostic depends on the extension pragma in the earlier versions.
+  // There is no indication that this behavior is expected.
   (void) 1.0; // expected-warning {{double precision constant requires cl_khr_fp64}}
 }
 #endif
@@ -79,13 +92,11 @@
   double4 d4 = {0.0f, 2.0f, 3.0f, 1.0f};
 #ifdef NOFP64
 // expected-error@-3 {{use of type 'double' requires cl_khr_fp64 support}}
-// expected-error@-3 {{use of type 'double4' (vector of 4 'double' values) requires cl_khr_fp64 support}}
 #endif
 
   (void) 1.0;
-
 #ifdef NOFP64
-// expected-warning@-3{{double precision constant requires cl_khr_fp64, casting to single precision}}
+// expected-warning@-2{{double precision constant requires cl_khr_fp64, casting to single precision}}
 #endif
 }
 
@@ -96,6 +107,11 @@
 
 #if (defined(__OPENCL_C_VERSION__) && __OPENCL_C_VERSION__ < 120)
 void f3(void) {
-  double d; // expected-error {{type 'double' requires cl_khr_fp64 support}}
+  double d;
+#ifdef NOFP64
+// expected-error@-2 {{type 'double' requires cl_khr_fp64 support}}
+#elif !defined(NOPEDANTIC)
+// expected-warning@-4 {{Clang permits use of type 'double' regardless pragma if 'cl_khr_fp64' is supported}}
+#endif
 }
 #endif