On Fri, 17 Nov 2023 06:06:16 GMT, Jatin Bhateja <jbhat...@openjdk.org> wrote:
> > BTW, I have two questions: > > > > 1. An intrinsic which should accept the vector as index like non-subword > > gather is more benefical in real applications. See: [8287289: > > Gather/Scatter with Index Vector > > panama-vector#201](https://github.com/openjdk/panama-vector/pull/201) > > please. > > 2. Do you have the plan for adding such optimization for subword scatter in > > future? > > > > Thanks, Xiaohong > > I agree, proposal looks reasonable to me, but given that x86 ISA does not > have direct sub-word gather instruction hence we will always need to pass > index array to inline expander. Existing interface provisions passing both > index array and vector. So in the x86 backend implementation, are the indexs finally stored into a vector register? Per my understand, it looks that way. If so, maybe an alternative is 1) just making the intrinsics accept an index vector like non-subword types, and 2) calling several times such load-gather intrinsics in java implementation of the subword gather (e.g. 4 load-gather for byte gather with int indexes). That means we can move the complex operations to java side, and compiler should only cover a single load-gather operation. This may make the subword unify with non-subword gathers in compiler/intrinsics side. ------------- PR Comment: https://git.openjdk.org/jdk/pull/16354#issuecomment-1818077141
