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
@@ -830,8 +830,8 @@
 def err_opencl_cast_to_half : Error<"casting to type %0 is not allowed">;
 def err_opencl_half_declaration : Error<
   "declaring variable of type %0 is not allowed">;
-def err_opencl_half_param : Error<
-  "declaring function parameter of type %0 is not allowed; did you forget * ?">;
+def err_opencl_invalid_param : Error<
+  "declaring function parameter of type %0 is not allowed%select{; did you forget * ?|}1">;
 def err_opencl_invalid_return : Error<
   "declaring function return value of type %0 is not allowed %select{; did you forget * ?|}1">;
 def warn_enum_value_overflow : Warning<"overflow in enumeration value">;
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
@@ -5139,8 +5139,8 @@
             // FIXME: This really should be in BuildFunctionType.
             if (S.getLangOpts().OpenCL) {
               if (!S.getOpenCLOptions().isEnabled("cl_khr_fp16")) {
-                S.Diag(Param->getLocation(),
-                  diag::err_opencl_half_param) << ParamTy;
+                S.Diag(Param->getLocation(), diag::err_opencl_invalid_param)
+                    << ParamTy << 0;
                 D.setInvalidType();
                 Param->setInvalidDecl();
               }
@@ -5159,6 +5159,11 @@
                 Param->setKNRPromoted(true);
               }
             }
+          } else if (S.getLangOpts().OpenCL && ParamTy->isBlockPointerType()) {
+            // OpenCL 2.0 s6.12.5: A block cannot be a parameter of a function.
+            S.Diag(Param->getLocation(), diag::err_opencl_invalid_param)
+                << ParamTy << 1 /*hint off*/;
+            D.setInvalidType();
           }
 
           if (LangOpts.ObjCAutoRefCount && Param->hasAttr<NSConsumedAttr>()) {
diff --git a/clang/test/CodeGenOpenCL/blocks.cl b/clang/test/CodeGenOpenCL/blocks.cl
--- a/clang/test/CodeGenOpenCL/blocks.cl
+++ b/clang/test/CodeGenOpenCL/blocks.cl
@@ -70,26 +70,6 @@
 
 // COMMON-NOT: define{{.*}}@__foo_block_invoke_kernel
 
-// Test that we support block arguments.
-// COMMON-LABEL: define {{.*}} @blockArgFunc
-int blockArgFunc(int (^ bl)(void)) {
-  return bl();
-}
-
-// COMMON-LABEL: define {{.*}} @get21
-// COMMON: define {{.*}} @__get21_block_invoke
-// COMMON: ret i32 21
-int get21() {
-  return blockArgFunc(^{return 21;});
-}
-
-// COMMON-LABEL: define {{.*}} @get42
-// COMMON: define {{.*}} @__get42_block_invoke
-// COMMON: ret i32 42
-int get42() {
-  return blockArgFunc(^{return 42;});
-}
-
 // COMMON-LABEL: define {{.*}}@call_block
 // call {{.*}}@__call_block_block_invoke
 int call_block() {
diff --git a/clang/test/Frontend/opencl.cl b/clang/test/Frontend/opencl.cl
--- a/clang/test/Frontend/opencl.cl
+++ b/clang/test/Frontend/opencl.cl
@@ -21,7 +21,7 @@
 #endif
 #endif
 
-void f(void (^g)(void)) {
+typedef int (^bl_t)(void);
 #if defined(__OPENCL_C_VERSION__) || defined(__OPENCL_CPP_VERSION__)
 #if !defined(BLOCKS) && (defined(__OPENCL_CPP_VERSION__)  || __OPENCL_C_VERSION__ != CL_VERSION_2_0)
   // expected-error@-3{{blocks support disabled - compile with -fblocks or for OpenCL 2.0}}
@@ -29,7 +29,6 @@
 #else
   // expected-error@-6{{blocks support disabled - compile with -fblocks or pick a deployment target that supports them}}
 #endif
-}
 
 // CHECK-INVALID-OPENCL-VERSION11: warning: OpenCL version 1.1 does not support the option '-cl-strict-aliasing'
 // CHECK-INVALID-OPENCL-VERSION12: warning: OpenCL version 1.2 does not support the option '-cl-strict-aliasing'
diff --git a/clang/test/SemaOpenCL/invalid-block.cl b/clang/test/SemaOpenCL/invalid-block.cl
--- a/clang/test/SemaOpenCL/invalid-block.cl
+++ b/clang/test/SemaOpenCL/invalid-block.cl
@@ -1,7 +1,7 @@
 // RUN: %clang_cc1 -verify -fblocks -cl-std=CL2.0 %s
 
 // OpenCL v2.0 s6.12.5
-void f0(int (^const bl)());
+void f0(int (^const bl)()); // expected-error{{declaring function parameter of type 'int (__generic ^const __private)(void)' is not allowed}}
 // All blocks declarations must be const qualified and initialized.
 void f1() {
   int (^bl1)(void) = ^() {
@@ -26,9 +26,18 @@
   };
 }
 
-// A block cannot be the return value of a function.
+// A block cannot be the return value or parameter of a function.
 typedef int (^bl_t)(void);
-bl_t f3(bl_t bl); // expected-error{{declaring function return value of type 'bl_t' (aka 'int (__generic ^const)(void)') is not allowed}}
+bl_t f3a(int);     // expected-error{{declaring function return value of type 'bl_t' (aka 'int (__generic ^const)(void)') is not allowed}}
+bl_t f3b(bl_t bl);
+// expected-error@-1{{declaring function return value of type 'bl_t' (aka 'int (__generic ^const)(void)') is not allowed}}
+// expected-error@-2{{declaring function parameter of type '__private bl_t' (aka 'int (__generic ^const __private)(void)') is not allowed}}
+void f3c() {
+  // Block with a block argument.
+  int (^const bl2)(bl_t block_arg) = ^() { // expected-error{{declaring function parameter of type '__private bl_t' (aka 'int (__generic ^const __private)(void)') is not allowed}}
+    return block_arg(); // expected-error{{implicit declaration of function 'block_arg' is invalid in OpenCL}}
+  };
+}
 
 struct bl_s {
   int (^bl)(void); // expected-error {{the 'int (__generic ^const)(void)' type cannot be used to declare a structure or union field}}