[OpenCL] Implement as_type operator as alias of __builtin_astype.

Reviewers: Anastasia

Reviewed By: Anastasia

Subscribers: cfe-commits, yaxunl, bader

Differential Revision: https://reviews.llvm.org/D28136

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@297947 91177308-0d34-0410-b5e6-96231b3b80d8

test/SemaOpenCL/as_type.cl

-// RUN: %clang_cc1 %s -emit-llvm -triple spir-unknown-unknown -o - -verify -fsyntax-only
-
-typedef __attribute__(( ext_vector_type(3) )) char char3;
-typedef __attribute__(( ext_vector_type(16) )) char char16;
+// RUN: %clang_cc1 %s -emit-llvm -triple spir-unknown-unknown -finclude-default-header -o - -verify -fsyntax-only
 
 char3 f1(char16 x) {
   return  __builtin_astype(x, char3); // expected-error{{invalid reinterpretation: sizes of 'char3' (vector of 3 'char' values) and 'char16' (vector of 16 'char' values) must match}}
@@ -11,3 +8,7 @@ char16 f3(int x) {
   return __builtin_astype(x, char16); // expected-error{{invalid reinterpretation: sizes of 'char16' (vector of 16 'char' values) and 'int' must match}}
 }
 
+void foo() {
+    char src = 1;
+    int dst = as_int(src); // expected-error{{invalid reinterpretation: sizes of 'int' and 'char' must match}}
+}