8335220: C2: Missing check for Opaque4 node in EscapeAnalysis #19921

vnkozlov · 2024-06-27T05:33:11Z

While testing Leyden Early Release the problem was found in C2 EscapeAnalysis, in new code which handles allocations merge. ConnectionGraph:: can_reduce_check_users() have incomplete checks which missed case with Opaque4 node between If and Bool nodes. As result we hit assert in ConnectionGraph::specialize_cmp() when trying to access inputs of Cmp node

Node* curr_cmp = curr_ctrl->in(0)->in(1)->in(1); // true/false -> if -> bool -> cmp
con = curr_cmp->in(1)->is_Con() ? curr_cmp->in(1) : curr_cmp->in(2);

This code was introduce for ReduceAllocationMerges optimization JDK-8316991 in JDK-23. There was followup fix JDK-8330853 to add more checks but it missed this case.

I added more strict check in can_reduce_check_users() to catch such cases. And added asserts in specialize_cmp() to verify expected nodes.

Tested tier1-3.hs-stress,hs-xcomp

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-8335220: C2: Missing check for Opaque4 node in EscapeAnalysis (Bug - P3)

Reviewers

Christian Hagedorn (@chhagedorn - Reviewer) ⚠️ Review applies to a0687aee
Cesar Soares Lucas (@JohnTortugo - Author)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/19921/head:pull/19921
$ git checkout pull/19921

Update a local copy of the PR:
$ git checkout pull/19921
$ git pull https://git.openjdk.org/jdk.git pull/19921/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 19921

View PR using the GUI difftool:
$ git pr show -t 19921

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/19921.diff

Webrev

Link to Webrev Comment

bridgekeeper · 2024-06-27T05:33:39Z

👋 Welcome back kvn! 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 · 2024-06-27T05:34:42Z

@vnkozlov 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:

8335220: C2: Missing check for Opaque4 node in EscapeAnalysis

Reviewed-by: chagedorn, cslucas

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 17 new commits pushed to the master branch:

0e6b0cb: 8334886: jdk/jfr/api/recording/time/TestTimeMultiple.java failed with RuntimeException: getStopTime() > afterStop
b6ffb44: 8335135: HttpURLConnection#HttpInputStream does not throw IOException when response is truncated
4ab7e98: 8330842: Support AES CBC with Ciphertext Stealing (CTS) in SunPKCS11
5909d54: 8326820: Metadata artificially kept alive
d5375c7: 8333308: javap --system handling doesn't work on internal class names
6b961ac: 8333786: Serial: Remove SerialHeap::_incremental_collection_failed
50dd962: 8335007: Inline OopMapCache table
79a2301: 8322859: Parallel: Move transform_stack_chunk
37e7698: 8335154: jcmd VM.classes -verbose=false does not set verbose to false
f3b69da: 8335136: Underscore as parameter name in one-parameter functional types fails to compile
... and 7 more: https://git.openjdk.org/jdk/compare/4ebb77120af5a4ccbfde63b24cb50e05a3161f16...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 · 2024-06-27T05:35:22Z

@vnkozlov 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.

mlbridge · 2024-06-27T05:38:18Z

Webrevs

01: Full - Incremental (c06f6ce0)
00: Full (a0687aee)

chhagedorn

Otherwise, looks good! Were you also able to reproduce this in mainline?

chhagedorn · 2024-06-27T07:40:52Z

src/hotspot/share/opto/escape.cpp

            Node* iff_cmp = iff->in(1)->in(1);
            int opc = iff_cmp->Opcode();
-            if ((opc == Op_CmpP || opc == Op_CmpN) && !can_reduce_cmp(n, iff_cmp)) {
+            can_reduce = (opc == Op_CmpP || opc == Op_CmpN) && can_reduce_cmp(n, iff_cmp);


Can you add a comment here that we could have an Opaque4 node for which we want to bail out?

JohnTortugo

LGTM. Thank you for fixing.

vnkozlov · 2024-06-27T16:04:38Z

Thank you, Christian and Cesar, for reviews.

vnkozlov · 2024-06-27T16:04:52Z

/integrate

openjdk · 2024-06-27T16:06:36Z

Going to push as commit 9d986a0.
Since your change was applied there have been 17 commits pushed to the master branch:

0e6b0cb: 8334886: jdk/jfr/api/recording/time/TestTimeMultiple.java failed with RuntimeException: getStopTime() > afterStop
b6ffb44: 8335135: HttpURLConnection#HttpInputStream does not throw IOException when response is truncated
4ab7e98: 8330842: Support AES CBC with Ciphertext Stealing (CTS) in SunPKCS11
5909d54: 8326820: Metadata artificially kept alive
d5375c7: 8333308: javap --system handling doesn't work on internal class names
6b961ac: 8333786: Serial: Remove SerialHeap::_incremental_collection_failed
50dd962: 8335007: Inline OopMapCache table
79a2301: 8322859: Parallel: Move transform_stack_chunk
37e7698: 8335154: jcmd VM.classes -verbose=false does not set verbose to false
f3b69da: 8335136: Underscore as parameter name in one-parameter functional types fails to compile
... and 7 more: https://git.openjdk.org/jdk/compare/4ebb77120af5a4ccbfde63b24cb50e05a3161f16...master

Your commit was automatically rebased without conflicts.

openjdk · 2024-06-27T16:06:43Z

@vnkozlov Pushed as commit 9d986a0.

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

8335220: C2: Missing check for Opaque4 node in EscapeAnalysis

a0687ae

openjdk bot added the rfr Pull request is ready for review label Jun 27, 2024

openjdk bot added the hotspot-compiler hotspot-compiler-dev@openjdk.org label Jun 27, 2024

chhagedorn approved these changes Jun 27, 2024

View reviewed changes

openjdk bot added the ready Pull request is ready to be integrated label Jun 27, 2024

Add comment about Opaque4

c06f6ce

JohnTortugo approved these changes Jun 27, 2024

View reviewed changes

openjdk bot added the integrated Pull request has been integrated label Jun 27, 2024

openjdk bot closed this Jun 27, 2024

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Jun 27, 2024

vnkozlov deleted the 8335220 branch June 27, 2024 16:15

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

8335220: C2: Missing check for Opaque4 node in EscapeAnalysis #19921

8335220: C2: Missing check for Opaque4 node in EscapeAnalysis #19921

Uh oh!

vnkozlov commented Jun 27, 2024 •

edited by openjdk bot

Loading

Uh oh!

bridgekeeper bot commented Jun 27, 2024

Uh oh!

openjdk bot commented Jun 27, 2024 •

edited

Loading

Uh oh!

openjdk bot commented Jun 27, 2024

Uh oh!

mlbridge bot commented Jun 27, 2024 •

edited

Loading

Uh oh!

chhagedorn left a comment

Uh oh!

chhagedorn Jun 27, 2024

Uh oh!

vnkozlov Jun 27, 2024

Uh oh!

JohnTortugo left a comment

Uh oh!

vnkozlov commented Jun 27, 2024

Uh oh!

vnkozlov commented Jun 27, 2024

Uh oh!

openjdk bot commented Jun 27, 2024

Uh oh!

openjdk bot commented Jun 27, 2024

Uh oh!

Reviewers

Assignees

Labels

Milestone

Development

Uh oh!

3 participants

8335220: C2: Missing check for Opaque4 node in EscapeAnalysis #19921

8335220: C2: Missing check for Opaque4 node in EscapeAnalysis #19921

Uh oh!

Conversation

vnkozlov commented Jun 27, 2024 • edited by openjdk bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Progress

Issue

Reviewers

Reviewing

Webrev

Uh oh!

bridgekeeper bot commented Jun 27, 2024

Uh oh!

openjdk bot commented Jun 27, 2024 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

openjdk bot commented Jun 27, 2024

Uh oh!

mlbridge bot commented Jun 27, 2024 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Webrevs

Uh oh!

chhagedorn left a comment

Choose a reason for hiding this comment

Uh oh!

chhagedorn Jun 27, 2024

Choose a reason for hiding this comment

Uh oh!

vnkozlov Jun 27, 2024

Choose a reason for hiding this comment

Uh oh!

JohnTortugo left a comment

Choose a reason for hiding this comment

Uh oh!

vnkozlov commented Jun 27, 2024

Uh oh!

vnkozlov commented Jun 27, 2024

Uh oh!

openjdk bot commented Jun 27, 2024

Uh oh!

openjdk bot commented Jun 27, 2024

Uh oh!

Reviewers

Assignees

Labels

Milestone

Development

Uh oh!

3 participants

vnkozlov commented Jun 27, 2024 •

edited by openjdk bot

Loading

openjdk bot commented Jun 27, 2024 •

edited

Loading

mlbridge bot commented Jun 27, 2024 •

edited

Loading