[jdk25u-dev] RFR: 8370405: C2: mismatched store from MergeStores wrongly scalarized in allocation elimination [v2]

[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 incremental webrev excludes the unrelated changes brought in by the merge/rebase.

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Changes:
  - all: https://git.openjdk.org/jdk25u-dev/pull/10/files
  - new: https://git.openjdk.org/jdk25u-dev/pull/10/files/0b6efa6d..0b6efa6d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk25u-dev&pr=10&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk25u-dev&pr=10&range=00-01

  Stats: 0 lines in 0 files changed: 0 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