correct the comment on potentical fixes to this bug
#include <omp.h>
// This smoke test has shows two problems.
-// The first is compile fail when the subtype has a smaller size than
-// the actual type.
+// The first is compile fail when the subtype has a smaller size than 4 bytes
+// That is both char and short fail. We need to generate compile fail
+// for amdgcn when atomic type is char or short OR use a temp 4 byte
+// value, which may not be atomic.
//
// The 2nd problem is a runtime fail. num_threads(64) has no control over
// actual number of threads when the default thread limit is 256.
