RFR: 8342692: C2: MemorySegment API slow with short running loops [v5]

[Emanuel Peter]

On Wed, 4 Dec 2024 07:41:24 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Roland Westrelin has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 21 commits:
>> 
>>  - Merge branch 'master' into JDK-8342692
>>  - whitespaces
>>  - more
>>  - merge
>>  - more
>>  - one more test
>>  - Merge branch 'master' into JDK-8342692
>>  - more
>>  - more
>>  - Merge branch 'master' into JDK-8342692
>>  - ... and 11 more: https://git.openjdk.org/jdk/compare/3b21a298...74c38342
>
> src/hotspot/share/opto/loopTransform.cpp line 140:
> 
>> 138:       udiff = uinit_con - ulimit_con;
>> 139:     }
>> 140:     julong utrip_count = udiff / ABS(stride_con);
> 
> Could `stride_con` be `min_int`?

I wonder if we should start converting all these computations to `noOverflowInt`, just to avoid possible overflows etc.

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PR Review Comment: https://git.openjdk.org/jdk/pull/21630#discussion_r1868864818