8373453: C2 SuperWord: must handle load slices that have loads with different memory inputs

[eme64]

Hi all,

This pull request contains a backport of commit da14813a from the openjdk/jdk repository.

The commit being backported was authored by Emanuel Peter on 7 Jan 2026 and was reviewed by Vladimir Kozlov, Tobias Hartmann and Quan Anh Mai.

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-8373453: C2 SuperWord: must handle load slices that have loads with different memory inputs (Bug - P3)

Reviewers

• Tobias Hartmann (@TobiHartmann - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/29123/head:pull/29123
$ git checkout pull/29123

Update a local copy of the PR:
$ git checkout pull/29123
$ git pull https://git.openjdk.org/jdk.git pull/29123/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 29123

View PR using the GUI difftool:
$ git pr show -t 29123

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/29123.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back epeter! A progress list of the required criteria for merging this PR into jdk26 will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@eme64 This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8373453: C2 SuperWord: must handle load slices that have loads with different memory inputs

Reviewed-by: thartmann

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 5 new commits pushed to the jdk26 branch:

• e0f1c3a: 8351889: C2 crash: assertion failed: Base pointers must match (addp 344)
• 9ba5d6f: 8374433: java/util/Locale/PreserveTagCase.java does not run any tests
• 0981794: 8374642: EscapeHash macro fails with GNU make 4.3 and 4.4
• ... and 2 more: https://git.openjdk.org/jdk/compare/5964a12adc186be17cb34ab8032b9d07caae1551...jdk26

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the jdk26 branch, type /integrate in a new comment.

[openjdk]

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

[openjdk]

@eme64 The following label will be automatically applied to this pull request:

• hotspot-compiler

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[TobiHartmann]

Looks good.

[mlbridge]

Webrevs

• 00: Full (37d9e49b)

[eme64]

@TobiHartmann Thanks for the reviews!

/integrate

[openjdk]

Going to push as commit 2d26730.
Since your change was applied there have been 6 commits pushed to the jdk26 branch:

• 10d97c5: 8365570: C2 fails assert(false) failed: Unexpected node in SuperWord truncation: CastII
• e0f1c3a: 8351889: C2 crash: assertion failed: Base pointers must match (addp 344)
• 9ba5d6f: 8374433: java/util/Locale/PreserveTagCase.java does not run any tests
• ... and 3 more: https://git.openjdk.org/jdk/compare/5964a12adc186be17cb34ab8032b9d07caae1551...jdk26

Your commit was automatically rebased without conflicts.

[openjdk]

@eme64 Pushed as commit 2d26730.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.