Do not violate the opencl casting rules. This test case still illustrates the problem. In the future, we should throw an error when doing invalid casting.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134570 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGenOpenCL/2011-04-15-vec-init-from-vec.cl

@@ -1,12 +1,11 @@
 // RUN: %clang_cc1 %s -emit-llvm -o %t
 
 typedef __attribute__((ext_vector_type(4)))  unsigned char uchar4;
-typedef __attribute__((ext_vector_type(4)))  unsigned int int4;
 typedef __attribute__((ext_vector_type(8))) unsigned char uchar8;
 
 // OpenCL allows vectors to be initialized by vectors Handle bug in
 // VisitInitListExpr for this case below.
-void foo( int4 v )
+void foo( uchar8 x )
 {
-  uchar4 val[4] = {{(uchar4){((uchar8)(v.lo)).lo}}};
-}
+  uchar4 val[4] = {{(uchar4){x.lo}}};
+}