8323101: C2: assert(n->in(0) == nullptr) failed: divisions with zero check should already have bailed out earlier in split-if

[shipilev]

Clean backport to fix a C2 corner case.

Additional testing:

• MacOS AArch64 server fastdebug: new tests fail without the patch, pass with the patch
• Linux AArch64 server fastdebug, tier{1,2,3,4}

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8323101 needs maintainer approval

Issue

• JDK-8323101: C2: assert(n->in(0) == nullptr) failed: divisions with zero check should already have bailed out earlier in split-if (Bug - P2 - Approved)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk21u-dev.git pull/179/head:pull/179
$ git checkout pull/179

Update a local copy of the PR:
$ git checkout pull/179
$ git pull https://git.openjdk.org/jdk21u-dev.git pull/179/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 179

View PR using the GUI difftool:
$ git pr show -t 179

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk21u-dev/pull/179.diff

Webrev

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[bridgekeeper]

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

[openjdk]

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

[openjdk]

⚠️ @shipilev This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[mlbridge]

Webrevs

• 01: Full - Incremental (4e643e86)
• 00: Full (c8eb23a8)

[shipilev]

/approval request Clean backport to fix a C2 corner case. Applies cleanly. New tests fail without the patch, and pass with it.

[openjdk]

@shipilev
8323101: The approval request has been created successfully.

[openjdk]

@shipilev 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:

8323101: C2: assert(n->in(0) == nullptr) failed: divisions with zero check should already have bailed out earlier in split-if

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 2 new commits pushed to the master branch:

• c971925: 8318157: RISC-V: implement ensureMaterializedForStackWalk intrinsic
• 2518d20: 8323154: C2: assert(cmp != nullptr && cmp->Opcode() == Op_Cmp(bt)) failed: no exit test

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
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 master branch, type /integrate in a new comment.

[shipilev]

/integrate

[openjdk]

Going to push as commit 869df3b.
Since your change was applied there have been 3 commits pushed to the master branch:

• 0466741: 8315611: Open source swing text/html and tree test
• c971925: 8318157: RISC-V: implement ensureMaterializedForStackWalk intrinsic
• 2518d20: 8323154: C2: assert(cmp != nullptr && cmp->Opcode() == Op_Cmp(bt)) failed: no exit test

Your commit was automatically rebased without conflicts.

[openjdk]

@shipilev Pushed as commit 869df3b.

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