Integrated: 8336635: Add IR test for Reference.refersTo intrinsic

[Aleksey Shipilev]

On Wed, 17 Jul 2024 09:52:48 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> As the follow-up for [JDK-8256999](https://bugs.openjdk.org/browse/JDK-8256999), we can directly test for the (absence of) GC barriers in C2 `Reference.refersTo` intrinsic. This would be come less relevant for G1 after Late Barrier expansion lands, but would still be relevant for Shenandoah for a while. It would also be good for backports.
> 
> Additional testing:
>  - [x] Test fails when I deliberately remove `AS_NO_KEEPALIVE` from the C2 intrinsic
>  - [x] Test passes with GC explicitly passed as `TEST_VM_OPTS`

This pull request has now been integrated.

Changeset: c73b3cb5
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/c73b3cb5996723c5a15c833a9da059b79c99cf9c
Stats:     156 lines in 1 file changed: 156 ins; 0 del; 0 mod

8336635: Add IR test for Reference.refersTo intrinsic

Reviewed-by: thartmann, kvn

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PR: https://git.openjdk.org/jdk/pull/20215