For example; a vector double splat looks like this: Another example: Note in the example above the cast to __v2df for the operation. Both __m128d and __v2df are vector double, but __v2df does no have the __may_alias__ attribute. And one more example: Note this requires a cast for the compiler to generate the correct code for the intended operation. The parameters and result are the generic interface type __m128i, which is a vector long long with the __may_alias__ attribute. But operation is a vector multiply low on unsigned short elements. So not only do we use the cast to drop the __may_alias__ attribute but we also need to cast to the correct type (__v8hu or vector unsigned short) for the specified operation. I have successfully copied these (and similar) source snippets over to the PPC64LE implementation unchanged. This of course assumes the associated types are defined and with compatible attributes.