On Thu, 2 Oct 2025 09:23:20 GMT, Bhavana Kilambi <[email protected]> wrote:
>> src/hotspot/cpu/aarch64/aarch64_vector.ad line 272:
>>
>>> 270: if (length_in_bytes > 16 || !is_feat_fp16_supported()) {
>>> 271: return false;
>>> 272: }
>>
>> Reductions with `length_in_bytes < 8` should also be skipped. Because such
>> operations are not supported now, while the IRs with 32-bit vector size
>> might exist, right?
>
> Hi @XiaohongGong, yes `length_in_bytes < 8` is also not supported and
> currently we support only for vector lengths of 8B and 16B.
> IRs with 32-bit vector size might exist but we do not have an optimized
> implementation for 32B vector lengths and thus I have disabled it. Instead of
> that, it generates the 16B scalarized Neon instruction sequence for a 32B
> vector length. Is this what you were asking?
I mean do we need to check the length_in_bytes < 8, such as:
Suggestion:
if (length_in_bytes < 8 || length_in_bytes > 16 ||
!is_feat_fp16_supported()) {
return false;
}
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/27526#discussion_r2409091499
