Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -3406,8 +3406,14 @@
       if (getLangOpts().SinglePrecisionConstants) {
         Res = ImpCastExprToType(Res, Context.FloatTy, CK_FloatingCast).get();
       } else if (getLangOpts().OpenCL &&
-                 !((getLangOpts().OpenCLVersion >= 120) ||
+                 !((getLangOpts().OpenCLVersion >= 120 &&
+                    Context.getTargetInfo()
+                        .getSupportedOpenCLOpts()
+                        .cl_khr_fp64) ||
                    getOpenCLOptions().cl_khr_fp64)) {
+        // Impose single-precision float type when:
+        //  - in CL 1.2 or above and cl_khr_fp64 is not supported, or
+        //  - in CL 1.1 or below and cl_khr_fp64 is not enabled.
         Diag(Tok.getLocation(), diag::warn_double_const_requires_fp64);
         Res = ImpCastExprToType(Res, Context.FloatTy, CK_FloatingCast).get();
       }
Index: lib/Sema/SemaType.cpp
===================================================================
--- lib/Sema/SemaType.cpp
+++ lib/Sema/SemaType.cpp
@@ -1413,7 +1413,8 @@
       Result = Context.DoubleTy;
 
     if (S.getLangOpts().OpenCL &&
-        !((S.getLangOpts().OpenCLVersion >= 120) ||
+        !((S.getLangOpts().OpenCLVersion >= 120 
+           && S.Context.getTargetInfo().getSupportedOpenCLOpts().cl_khr_fp64) ||
           S.getOpenCLOptions().cl_khr_fp64)) {
       S.Diag(DS.getTypeSpecTypeLoc(), diag::err_type_requires_extension)
           << Result << "cl_khr_fp64";
Index: test/SemaOpenCL/extensions.cl
===================================================================
--- test/SemaOpenCL/extensions.cl
+++ test/SemaOpenCL/extensions.cl
@@ -1,13 +1,16 @@
 // 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
 
 // Test with a target not supporting fp64.
 // RUN: %clang_cc1 %s -triple r600-unknown-unknown -target-cpu r600 -verify -pedantic -fsyntax-only -DNOFP64
 
+#if __OPENCL_C_VERSION__ < 120
 void f1(double da) { // expected-error {{type 'double' requires cl_khr_fp64 extension}}
   double d; // expected-error {{type 'double' requires cl_khr_fp64 extension}}
   (void) 1.0; // expected-warning {{double precision constant requires cl_khr_fp64}}
 }
+#endif
 
 #pragma OPENCL EXTENSION cl_khr_fp64 : enable
 #ifdef NOFP64
@@ -21,8 +24,12 @@
 #endif
 
   (void) 1.0;
+#ifdef FP64
+// expected-no-diagnostics
+#endif
+
 #ifdef NOFP64
-// expected-warning@-2{{double precision constant requires cl_khr_fp64, casting to single precision}}
+// expected-warning@-6{{double precision constant requires cl_khr_fp64, casting to single precision}}
 #endif
 }
 
@@ -31,6 +38,8 @@
 // expected-warning@-2{{unsupported OpenCL extension 'cl_khr_fp64' - ignoring}}
 #endif
 
+#if __OPENCL_C_VERSION__ < 120
 void f3(void) {
   double d; // expected-error {{type 'double' requires cl_khr_fp64 extension}}
 }
+#endif