8382536: C2: sharpen_type_after_if: assert(val->find_edge(con) > 0) failed: mismatch by iwanowww · Pull Request #31798 · openjdk/jdk

iwanowww · 2026-07-06T23:21:05Z

The shape of instanceof check matched by JDK-8372634 expects a constant to be a Con node. But it turns out it's not always the case: it can be a CastII when a value is provably constant after a runtime check.

The fix enhances the logic to properly match such IR shape.

Testing: hs-tier1 - hs-tier5

I confirm that I make this contribution in accordance with the OpenJDK Interim AI Policy.

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Issue

JDK-8382536: C2: sharpen_type_after_if: assert(val->find_edge(con) > 0) failed: mismatch (Bug - P3)(⚠️ The fixVersion in this issue is [27] but the fixVersion in .jcheck/conf is 28, a new backport will be created when this pr is integrated.)

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Christian Hagedorn (@chhagedorn - Reviewer)
Marc Chevalier (@marc-chevalier - Committer)

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bridgekeeper · 2026-07-06T23:23:09Z

👋 Welcome back vlivanov! 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 · 2026-07-06T23:23:53Z

@iwanowww 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:

8382536: C2: sharpen_type_after_if: assert(val->find_edge(con) > 0) failed: mismatch

Reviewed-by: chagedorn, mchevalier

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 26 new commits pushed to the master branch:

31dede3: 8368180: RISC-V: Remove redundant ext_Zicboz.enable_feature()
333deb2: 8380967: Canceled HttpClient.sendAsync futures throw inconsistent exceptions
05c93a1: 8387411: C2: assert((in_vt->isa_pvectmask() == nullptr) == (vt->isa_pvectmask() == nullptr)) failed: Both BVectMask, or both NVectMask, or both PVectMask
... and 23 more: https://git.openjdk.org/jdk/compare/01a9a4021848aabc4bb68600a89a380a76a33ff1...master

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.

openjdk · 2026-07-06T23:24:42Z

@iwanowww 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.

openjdk · 2026-07-06T23:24:46Z

The total number of required reviews for this PR has been set to 2 based on the presence of this label: hotspot-compiler. This can be overridden with the /reviewers command.

mlbridge · 2026-07-07T17:44:04Z

Webrevs

chhagedorn

Otherwise, the fix looks good to me, thanks!

chhagedorn · 2026-07-08T08:55:51Z

+      if ((btest == BoolTest::eq && tcon == success_tval) ||
+          (btest == BoolTest::ne && tcon->join(success_tval)->empty())) {


Maybe a small comment like this would help here:

// gen_instanceof() emits 1 on success and 0 on failure. // Check whether the current outer comparison selects the success value.

Optionally, we could also assert that the success and failure phi inputs are 1 and 0, respectively.

Done.

Optionally, we could also assert that the success and failure phi inputs are 1 and 0, respectively.

I'm not sure it always holds. It's part of IR shape matching: we know the shape of con/tcon and the check extends it to val (Phi) inputs.

I see, then let's leave it like that.

marc-chevalier

That looks good to me, but I agree with @chhagedorn comments. They helped me when reviewing.

chhagedorn

That looks good to me, thanks for the update!

chhagedorn · 2026-07-09T06:18:53Z

+      if ((btest == BoolTest::eq && tcon == success_tval) ||
+          (btest == BoolTest::ne && tcon->join(success_tval)->empty())) {


I see, then let's leave it like that.

iwanowww · 2026-07-09T16:55:38Z

Thanks for the reviews, Christian and Marc.

/integrate

openjdk · 2026-07-09T16:59:18Z

Going to push as commit 4d3723b.
Since your change was applied there have been 32 commits pushed to the master branch:

7544c91: 8387961: Shenandoah: Rework marked objects loop prefetch
a230a60: 8387795: Remove hard coded set of locales in LocaleData
095cf06: 8387404: Make ClassLoaderData::oops_do inlineable
... and 29 more: https://git.openjdk.org/jdk/compare/01a9a4021848aabc4bb68600a89a380a76a33ff1...master

Your commit was automatically rebased without conflicts.

openjdk · 2026-07-09T16:59:26Z

@iwanowww Pushed as commit 4d3723b.

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

iwanowww · 2026-07-10T22:56:11Z

/backport :jdk27

openjdk · 2026-07-10T22:57:10Z

@iwanowww the backport was successfully created on the branch backport-iwanowww-4d3723b8-jdk27 in my personal fork of openjdk/jdk. To create a pull request with this backport targeting openjdk/jdk:jdk27, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit 4d3723b8 from the openjdk/jdk repository.

The commit being backported was authored by Vladimir Ivanov on 9 Jul 2026 and was reviewed by Christian Hagedorn and Marc Chevalier.

Thanks!

If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk:

$ git fetch https://github.com/openjdk-bots/jdk.git backport-iwanowww-4d3723b8-jdk27:backport-iwanowww-4d3723b8-jdk27
$ git checkout backport-iwanowww-4d3723b8-jdk27
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk.git backport-iwanowww-4d3723b8-jdk27

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fix

38471dd

openjdk Bot added the hotspot-compiler hotspot-compiler-dev@openjdk.org label Jul 6, 2026

iwanowww marked this pull request as ready for review July 7, 2026 17:38

openjdk Bot added the rfr Pull request is ready for review label Jul 7, 2026

chhagedorn reviewed Jul 8, 2026

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marc-chevalier reviewed Jul 8, 2026

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Comment thread test/hotspot/jtreg/compiler/types/TestSubTypeCheckConstantCastII.java Outdated

iwanowww added 2 commits July 8, 2026 10:33

update

63fccc4

update

39e98cb

chhagedorn approved these changes Jul 9, 2026

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marc-chevalier approved these changes Jul 9, 2026

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openjdk Bot added the ready Pull request is ready to be integrated label Jul 9, 2026

openjdk Bot added the integrated Pull request has been integrated label Jul 9, 2026

openjdk Bot closed this Jul 9, 2026

openjdk Bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Jul 9, 2026

		if ((btest == BoolTest::eq && tcon == success_tval) \|\|
		(btest == BoolTest::ne && tcon->join(success_tval)->empty())) {

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