RFR: 8307423: [s390x] Represent Registers as values [v4]

[Lutz Schmidt]

On Sat, 6 May 2023 02:23:24 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

>> The recent Register implementation uses wild pointer (including null pointer) dereferences which exhibit undefined behavior. We should migrate away from pointer-based representation of Register values as it was done for x86 ([JDK-8292153](https://bugs.openjdk.org/browse/JDK-8292153)). Problems exist when trying to build with GCC 11.3.0 ([JDK-8307093](https://bugs.openjdk.org/browse/JDK-8307093)).
>> 
>> Tested `fastdebug, slowdebug, optimized, release build` , `tier1-test` on fastdebug build and build with GCC-9.5.0 as well.
>
> Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   more suggestions from @RealLucy

LGTM
Thank you for fixing, and for taking my requests into consideration.

LGTM
Thank you for fixing, and for taking my requests into consideration.

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Marked as reviewed by lucy (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13805#pullrequestreview-1416248187
PR Review: https://git.openjdk.org/jdk/pull/13805#pullrequestreview-1416248227