RFR: 8310190: C2 SuperWord: AlignVector is broken, generates misaligned packs [v16]

[Emanuel Peter]

On Fri, 24 Nov 2023 08:39:04 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

>> Emanuel Peter has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 67 commits:
>> 
>>  - Merge branch 'master' into JDK-8311586
>>  - TestBufferVectorization.java: Faye reported issue with AlignVector. Made to IR test, removed flagless
>>  - Merge branch 'master' into JDK-8311586
>>  - aarch64 match rule from Faye for VerifyVectorAlignment
>>  - Faye found failure on 256 SVE machine, fixed
>>  - Merge branch 'master' into JDK-8311586
>>  - fix flags register in VerifyAlignVector
>>  - Merge branch 'master' into JDK-8311586
>>  - small fix
>>  - Merge branch 'master' into JDK-8311586
>>  - ... and 57 more: https://git.openjdk.org/jdk/compare/e055fae1...b491fbcb
>
> src/hotspot/share/opto/superword.cpp line 3815:
> 
>> 3813:   //   lim0:     current pre-loop limit
>> 3814:   //   lim:      new pre-loop limit
>> 3815:   //   N:        difference between lim and lim0
> 
> I find it hard to remember which is which when reading the equations below. I suggest to use more explicit names:
> Suggestion:
> 
>   //   old_limit:     current pre-loop limit
>   //   new_limit:      new pre-loop limit
>   //   diff_limits:        difference between lim and lim0

done

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PR Review Comment: https://git.openjdk.org/jdk/pull/14785#discussion_r1417689474