On Mon, 30 Mar 2026 08:10:42 GMT, Emanuel Peter <[email protected]> wrote:

>> src/jdk.incubator.vector/share/classes/jdk/incubator/vector/AbstractVector.java
>>  line 505:
>> 
>>> 503:         int resSizeLog2 = domSizeLog2 + laneChangeLog2;
>>> 504:         // resSizeLog2 = 0 => 1-lane vector shrinking to 1-byte 
>>> lane-size
>>> 505:         // resSizeLog2 < 0 => small vector shrinking by more than a 
>>> lane-size
>> 
>> Do you mean `resSizeLog2 > 0 ...`?
>
> I did not write this - it was already there before!
> But you are right it is obvious non-sense, given the assert below 
> `assert(resSizeLog2 >= 0);`
> 
> I think I'm going to just delete these two lines. Given all the other 
> comments, they are now not very helpful any more. Let me know if you disagree.

Ah no wait. It is sensible and correct.
But maybe I can reformulate it.
`resSizeLog2 = 0` means the logical result is exactly a single byte.
`resSizeLog2 < 0` would mean we have less than a byte in total for the logial 
result. So a fractional byte. That is obviously non-sense, hence the assert 
below.

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PR Review Comment: https://git.openjdk.org/jdk/pull/30113#discussion_r3008235888

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