RFC: PR14880 vec_duplicate or vec_select?

[Aldy Hernandez]

> how about something like -
> 
> (vec_duplicate:V4SI
>    (vec_select:SI (reg:V4SI v1)
>                   (parallel [(const_int 3)]))
>    (const_int 4))

I don't care either way, but all you folks dealing with vectorization
need to come up with canonical ways of representing all this.  Then we
need to document it so every port does the same thing.

I'll wait for anyone else to comment on this by Monday, then I'll
implement the above (or anything y'all agree on).

> > BTW2, perhaps I'm not looking hard enough, but I don't see anywhere in
> > GCC where we're using vec_select or vec_duplicate.  Mind you, we must
> > get away from the unspec's eventually...
> 
> I found a couple occurrences of VEC_SELECT/VEC_DUPLICATE in simplify-rtx.c,
> combine.c.

Sweet!  Thanks.

Aldy