On Mon, 9 Dec 2024 13:47:10 GMT, Emanuel Peter <epe...@openjdk.org> wrote:
>> Quan Anh Mai has updated the pull request incrementally with one additional >> commit since the last revision: >> >> address reviews > > Ok, looks better. > > I've thought about this a little. And I am wondering if we cannot make the > use of Rearrange generally easier. > > What if we want to use the `VectorRearrangeNode` elsewhere? > One would assume that one could just check > `arch_supports_vector(Op_VectorRearrange, ...elem_bt)` > And then one could emit a `VectorRearrangeNode` for the given `elem_bt`. But > that is not the case, the user would have to also check for > `Matcher::vector_rearrange_requires_load_shuffle(shuffle_bt, num_elem)`, and > possibly add a `VectorLoadShuffleNode`. > I don't like this - it makes the use quite cumbersome. > > I have an idea for an alternative: > You add a `VectorRearrangeNode::Ideal`, which then transforms itself if we > have `Matcher::vector_rearrange_requires_load_shuffle`. > > I have not thought this through to the end, but it just seems it would be > easier to use Rearrange in the future this way. But maybe we know that we > will never use Rearrange in any other way, then I'm fine with this > implementation. What do you think @PaulSandoz ? @eme64 Yes I have thought about that. My idea is that once phase lowering is ready we will move the expansion there (#21599) . This removes the need to have a standalone method that checks if `LoadShuffleNode` is needed. The current situation is that `VectorRearrangeNode` is expected to come with `VectorLoadShuffleNode` so you cannot easily work with `VectorRearrangeNode`, either. ------------- PR Comment: https://git.openjdk.org/jdk/pull/21042#issuecomment-2528023981
