8352075: Perf regression accessing fields

[coleenp]

Hi all,

This pull request contains a backport of commit e18277b4 from the openjdk/jdk repository.

The commit being backported was authored by Radim Vansa on 12 Jun 2025 and was reviewed by Coleen Phillimore, Ioi Lam and Johan Sjölen.

This has been running cleanly in CI for a week now.

Thanks!

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8352075: Perf regression accessing fields (Bug - P3)

Reviewing

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$ git fetch https://git.openjdk.org/jdk.git pull/25877/head:pull/25877
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Update a local copy of the PR:
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$ git pull https://git.openjdk.org/jdk.git pull/25877/head

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$ git pr checkout 25877

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https://git.openjdk.org/jdk/pull/25877.diff

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[openjdk]

This backport pull request has now been updated with issue from the original commit.

[openjdk]

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[mlbridge]

Webrevs

• 00: Full (619afae0)

[rvansa]

Thank you for the backport! @shipilev indicated that the backport to 21 should wait a bit, could you clarify when should I file that (e.g. end of July, ...)?

[shipilev]

@shipilev indicated that the backport to 21 should wait a bit, could you clarify when should I file that (e.g. end of July, ...)?

I would say for the fairly big change like this, we want to wait until JDK 25 GA (that would pass the all-tests-run). It would be too late for Oct 2025 release, though. So realistically, this would target January 2026 release. You can pull this patch to your downstream JDK 21 to see if there are any troubles ahead of this path, this will also soothe 21u maintainer concerns, I think.