8286177: C2: "failed: non-reduction loop contains reduction nodes" assert failure

[GoeLin]

I backport this for parity with 11.0.17-oracle.

---

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-8286177: C2: "failed: non-reduction loop contains reduction nodes" assert failure

Reviewers

• Martin Doerr (@TheRealMDoerr - Reviewer)
• Paul Hohensee (@phohensee - Reviewer)
• Christoph Langer (@RealCLanger - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk11u-dev pull/1195/head:pull/1195
$ git checkout pull/1195

Update a local copy of the PR:
$ git checkout pull/1195
$ git pull https://git.openjdk.org/jdk11u-dev pull/1195/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 1195

View PR using the GUI difftool:
$ git pr show -t 1195

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk11u-dev/pull/1195.diff

[bridgekeeper]

👋 Welcome back goetz! 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.

[mlbridge]

Webrevs

• 02: Full - Incremental (a2760552)
• 01: Full - Incremental (71bc9cc1)
• 00: Full (71bc9cc1)

[openjdk-notifier]

The dependent pull request has now been integrated, and the target branch of this pull request has been updated. This means that changes from the dependent pull request can start to show up as belonging to this pull request, which may be confusing for reviewers. To remedy this situation, simply merge the latest changes from the new target branch into this pull request by running commands similar to these in the local repository for your personal fork:

git checkout goetz_backport_8286177
git fetch https://git.openjdk.org/jdk11u-dev master
git merge FETCH_HEAD
# if there are conflicts, follow the instructions given by git merge
git commit -m "Merge master"
git push

[openjdk-notifier]

@GoeLin Please do not rebase or force-push to an active PR as it invalidates existing review comments. All changes will be squashed into a single commit automatically when integrating. See OpenJDK Developers’ Guide for more information.

[TheRealMDoerr]

Seems like something went wrong. Original patch is much larger!

[GoeLin]

Hi Martin,
my force-push should have fixed this. I actually had expected this would be clean. Is there still something missing?

[TheRealMDoerr]

Yes, at least the "Files changed" tab doesn't show enough. I suggest to remove the Commit and replace it by a new one.

[GoeLin]

It shows two files. superword.cpp and the new test. What is missing? I don't see more files edited in the original change.

[phohensee]

I also see only two files. Lgtm.

[openjdk]

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

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

8286177: C2: "failed: non-reduction loop contains reduction nodes" assert failure

Reviewed-by: mdoerr, phh, clanger

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 12 new commits pushed to the master branch:

• 75519b1: 8285380: Fix typos in security
• ccd3de5: 8287223: C1: Inlining attempt through MH::invokeBasic() with null receiver
• 9c6fce3: 8290004: [PPC64] JfrGetCallTrace: assert(_pc != nullptr) failed: must have PC
• 3338986: 8289856: [PPC64] SIGSEGV in C2Compiler::init_c2_runtime() after JDK-8289060
• 9d0b5e5: 8290198: Shenandoah: a few Shenandoah tests failure after JDK-8214799 11u backport
• c9a7259: 8278067: Make HttpURLConnection default keep alive timeout configurable
• ab4a3e6: 8254318: Remove .hgtags
• 8b56027: 8193462: Fix Filer handling of package-info initial elements
• a27448e: 8266675: Optimize IntHashTable for encapsulation and ease of use
• bfc5746: 8203277: preflow visitor used during lambda attribution shouldn't visit class definitions inside the lambda body
• ... and 2 more: https://git.openjdk.org/jdk11u-dev/compare/4f1ac634d33131a005d6371ef048a5d1d0350b10...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.

[RealCLanger]

Looks correct to me, nothing missing.

[TheRealMDoerr]

Why does the 17u backport change 6 files openjdk/jdk17u-dev#495 while this one shows 2 files?

[TheRealMDoerr]

I guess it could be recognized as clean when using the hash from https://git.openjdk.java.net/jdk/commit/6458a56e60472fb2fbe8fa60bbc856dc95f50f07. The actual change LGTM, but the 17u question remains.

[GoeLin]

In the PR for 17 you see the files of the dependent pull request. It includes the predecessor change. Please look at the commit to 17u.
It's a bummer GitHub removes important information (that a change was a dependent pull request at some point), but spams this page with useless redundant information (Welcome back goetz).

[GoeLin]

Thanks for all the reviews!
/integrate

[openjdk]

Going to push as commit a10ef71.
Since your change was applied there have been 15 commits pushed to the master branch:

• 39eecbf: 8271078: jdk/incubator/vector/Float128VectorTests.java failed a subtest
• 8486da7: 8255729: com.sun.tools.javac.processing.JavacFiler.FilerOutputStream is inefficient
• a9c27da: 8236490: Compiler bug relating to @nonnull annotation
• 75519b1: 8285380: Fix typos in security
• ccd3de5: 8287223: C1: Inlining attempt through MH::invokeBasic() with null receiver
• 9c6fce3: 8290004: [PPC64] JfrGetCallTrace: assert(_pc != nullptr) failed: must have PC
• 3338986: 8289856: [PPC64] SIGSEGV in C2Compiler::init_c2_runtime() after JDK-8289060
• 9d0b5e5: 8290198: Shenandoah: a few Shenandoah tests failure after JDK-8214799 11u backport
• c9a7259: 8278067: Make HttpURLConnection default keep alive timeout configurable
• ab4a3e6: 8254318: Remove .hgtags
• ... and 5 more: https://git.openjdk.org/jdk11u-dev/compare/4f1ac634d33131a005d6371ef048a5d1d0350b10...master

Your commit was automatically rebased without conflicts.

[openjdk]

@GoeLin Pushed as commit a10ef71.

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