RFR: 8328938: C2 SuperWord: disable vectorization for large stride and scale [v4]

[Emanuel Peter]

On Tue, 2 Apr 2024 19:46:03 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> Emanuel Peter has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:
>> 
>>  - Merge branch 'JDK-8328938-abs-min-int-assert' of https://github.com/eme64/jdk into JDK-8328938-abs-min-int-assert
>>  - Apply suggestions from code review
>>    
>>    Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>
>>  - Merge branch 'master' into JDK-8328938-abs-min-int-assert
>>  - improve comments
>>  - 8328938
>
> src/hotspot/share/opto/vectorization.cpp line 411:
> 
>> 409:       abs(long_stride) >= max_val ||
>> 410:       abs(long_scale * long_stride) >= max_val) {
>> 411:     assert(!valid(), "adr stride*scale is too large");
> 
> Why you need assert?

If you look a few lines up, you can see that all other "bailouts" also check that the VPointer is invalid. I am simply matching the surrounding code. And it also makes it explicit, that the VPointer will be invalid, which is what I want.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/18485#discussion_r1549000771