[jdk21u] RFR: 8313248: C2: setScopedValueCache intrinsic exposes nullptr pre-values to store barriers

[Aleksey Shipilev]

On Wed, 9 Aug 2023 10:51:18 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Clean backport to fix Loom bug reproducing at least with Shenandoah, but also maybe with G1.
> 
> Additional testing:
>  - [x] macos-aarch64-server-fastdebug, original reproducer fails without the patch, passes with it

Testing is clean. Push approval is here.

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PR Comment: https://git.openjdk.org/jdk21u/pull/50#issuecomment-1673089281