RFR: 8255129: [PPC64, s390] Check vector_size_supported and add VectorReinterpret node

[Lutz Schmidt]

On Wed, 21 Oct 2020 13:28:38 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> match_rule_supported_vector on PPC64 and s390 need to check vector_size_supported.
> In addition, an implementation for VectorReinterpret is needed. It can get implemented empty when using src = dst register. Note that these 2 platforms support only one vector size at a time, so there's no need for move between different sizes.
> 
> I'd like to clean up match_rule_supported, too. Cases for which we return true don't need to get checked explicitely because true is default. And we don't need to check SpecialString... flags because they are handled by "disabled_by_jvm_flags". So they can still get disabled (e.g. by jdk/bin/java -XX:-TieredCompilation -XX:-SpecialStringIndexOf -XX:+PrintCompilation -XX:+PrintInlining TestString|grep StringLatin1::indexOf).

Martin,
these changes look good to me. There remains a lot to be implemented, though. :-) And thank you for cleaning up the code!
Best, Lutz

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Marked as reviewed by lucy (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/783