RFR: 8300257: C2: vectorization fails on some simple Memory Segment loops [v2]

[Roland Westrelin]

On Thu, 16 Mar 2023 08:52:49 GMT, Tobias Hartmann <thartmann 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 three commits:
>> 
>>  - NULL -> nullptr
>>  - Merge branch 'master' into JDK-8300257
>>  - fix & test
>
> src/hotspot/share/opto/superword.cpp line 4318:
> 
>> 4316:   if (opc == Op_AddI) {
>> 4317:     if (n->in(2)->is_Con() && invariant(n->in(1))) {
>> 4318:       maybe_add_to_invar(maybe_negate_invar(negate, n->in(1)));
> 
> It feels like `maybe_negate_invar` should be moved into `maybe_add_to_invar` and be controlled by a `negate` argument.

Thanks for the review. I applied your suggestions and made that change too.

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

PR: https://git.openjdk.org/jdk/pull/12942