On Mon, 8 Dec 2025 05:56:16 GMT, Eric Fang <[email protected]> wrote:
>> No, the starting value is `-1`, this test depends on the fact that we choose
>> the correct identity value for this particular operation as the starting
>> value, which this issue is about. As a result, it would be better to write
>> the test so that we do not depend on the identity value.
>>
>> byte res = a[idx];
>> for (int i = idx + 1; i < (idx + SPECIES.length()); i++) {
>> res = (byte) VectorMath.minUnsigned(res, a[i]);
>> }
>
> Okay, I got your point. I think this might be to maintain consistency with
> `UMINReduceMasked`; for the masked version, if no element is selected, it
> returns the identity value. I'm okay with both approaches, maybe let’s hear
> what @PaulSandoz thinks.
For masking we need to start with the identity or otherwise use the identify
when no mask bits are set. It would be better to declare as constants and refer
to them e.g., `UMAX_VALUE`, `UMIN_VALUE`. There are also other cases where we
use identity values for reduction and they follow the same pattern of
declaration and use.
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PR Review Comment: https://git.openjdk.org/jdk/pull/28692#discussion_r2600503579
