On Mon, 9 Dec 2024 13:55:46 GMT, Quan Anh Mai <qa...@openjdk.org> wrote:
>> 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. @merykitty Ok. Is there a chance we could wait for that additional phase to arrive then, and only do this refactor here afterward? I'd also be ok with a follow up RFE - it would just have to be filed and be clear who will take care of it ;) ------------- PR Comment: https://git.openjdk.org/jdk/pull/21042#issuecomment-2528038627
