[jdk25u-dev] RFR: 8370405: C2: mismatched store from MergeStores wrongly scalarized in allocation elimination [v3]

[Aleksey Shipilev]

> Fixes JDK 21 -> JDK 25 regression in C2 that can lead to miscompilation. There is a regression test that captures the failure.
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, new regression test fails without the fix, passes with it
>  - [ ] Linux x86_64 server fastdebug, `all`

Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains one commit:

  Backport 09a047f00c88d14505c42a966dedbc87b9be5bdf

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Changes: https://git.openjdk.org/jdk25u-dev/pull/10/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk25u-dev&pr=10&range=02
  Stats: 375 lines in 5 files changed: 375 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk25u-dev/pull/10.diff
  Fetch: git fetch https://git.openjdk.org/jdk25u-dev.git pull/10/head:pull/10

PR: https://git.openjdk.org/jdk25u-dev/pull/10