Draft JEP: Vector API

Ningsheng Jian ningsheng.jian at linaro.org
Thu Apr 12 02:50:22 UTC 2018

Hi Paul,

On 12 April 2018 at 08:31, Paul Sandoz <paul.sandoz at oracle.com> wrote:
> Hi,
> Expanding a little further on shapes.
> After some more thought i have my doubts that an explicit preferred shape is required. Vector computations can be written generic to shape and there is no need to expose a public type for a preferred shape (however, for optimal code generation the generic computations need to get inlined). Hiding the preferred shape behind a wildcard gives more flexibility since an existing public shape could be reused (as is the case right now), or something private, which might be the case for ARM SVE.

Yes, I agree. That will make the application code more portable.

> Speculating for ARM SVE i could imagine a single concrete implementation associated with a private preferred platform shape (the bit size and length methods would need to be made intrinsic so as to return constant values). It's probably not optimal to pre-generate given the bit size is platform specific (IIRC it can vary from 128 to 2048 bits in powers of 2).

It's 128 to 2048, multiply of 128 :-)
Thanks for thinking about SVE.


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