On Sat, Oct 13, 2012 at 10:52 AM, Marc Glisse <marc.gli...@inria.fr> wrote: > Hello, > > this patch provides an alternate pattern to let combine recognize scalar > operations that preserve the high part of a vector. If the strategy is all > right, I could do the same for more operations (mul, div, ...). Something > similar is also possible for V4SF (different pattern though), but probably > not as useful.
But, we _do_ have vec_merge pattern that describes the operation. Adding another one to each operation just to satisfy combine is IMO not correct approach. I'd rather see generic RTX simplification that simplifies your proposed pattern to vec_merge pattern. Also, as you mention in PR54855, Comment #5, the approach is too fragile... Uros.
