RFR: 8370519: C2: Hit MemLimit when running with +VerifyLoopOptimizations [v7]

[Manuel Hässig]

On Fri, 30 Jan 2026 13:35:16 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> For this failure memory stats are:
>> 
>> 
>> Total Usage: 1095525816 
>>     --- Arena Usage by Arena Type and compilation phase, at arena usage peak of 1095525816 ---
>>         Phase                         Total        ra      node      comp      type    states   reglive  regsplit   regmask superword     cienv        ha     other
>>         none                        5976032    331560   5402064    197512     33712     10200         0         0       984         0         0         0         0
>>         parse                       2716464     65456   1145480    196408   1112752         0         0         0         0         0    196368         0         0
>>         optimizer                     98184         0     32728         0     65456         0         0         0         0         0         0         0         0
>>         connectionGraph               32728         0         0     32728         0         0         0         0         0         0         0         0         0
>>         iterGVN                       32728         0     32728         0         0         0         0         0         0         0         0         0         0
>>         idealLoop                 918189632         0  38687056 872824784    392776         0         0         0         0         0   6285016         0         0
>>         idealLoopVerify             2228144         0         0   2228144         0         0         0         0         0         0         0         0         0
>>         macroExpand                   32728         0     32728         0         0         0         0         0         0         0         0         0         0
>>         graphReshape                  32728         0     32728         0         0         0         0         0         0         0         0         0         0
>>         matcher                    20135944   3369848   9033208   7536400     65456    131032         0         0         0         0         0         0         0
>>         postselect_cleanup           294872    294872         0         0         0         0         0         0         0         0         0         0         0
>>         scheduler                    752944    196488    556456         0         0         0         0         0         0         0         0         0         0
>>         regalloc                     388736    388736         0         0         0         0         0         0         0         0         0         0         0
>>        ...
>
> Roland Westrelin has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 19 additional commits since the last revision:
> 
>  - new test
>  - Merge branch 'master' into JDK-8370519
>  - Benoit's test case
>  - Merge branch 'master' into JDK-8370519
>  - package declaration
>  - review
>  - Merge branch 'master' into JDK-8370519
>  - Update test/hotspot/jtreg/compiler/c2/TestVerifyLoopOptimizationsHighMemUsage.java
>    
>    Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
>  - Update test/hotspot/jtreg/compiler/c2/TestVerifyLoopOptimizationsHighMemUsage.java
>    
>    Co-authored-by: Benoît Maillard <benoit.maillard at protonmail.com>
>  - Update src/hotspot/share/opto/loopnode.hpp
>    
>    Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
>  - ... and 9 more: https://git.openjdk.org/jdk/compare/78de1ad5...1284ae3c

Well, the CI tells me that the copyright years need updating.

src/hotspot/share/memory/arena.hpp line 2:

> 1: /*
> 2:  * Copyright (c) 2017, 2025, Oracle and/or its affiliates. All rights reserved.

Suggestion:

 * Copyright (c) 2017, 2026, Oracle and/or its affiliates. All rights reserved.

src/hotspot/share/opto/loopnode.cpp line 2:

> 1: /*
> 2:  * Copyright (c) 1998, 2025, Oracle and/or its affiliates. All rights reserved.

Suggestion:

 * Copyright (c) 1998, 2026, Oracle and/or its affiliates. All rights reserved.

src/hotspot/share/opto/loopnode.hpp line 2:

> 1: /*
> 2:  * Copyright (c) 1998, 2025, Oracle and/or its affiliates. All rights reserved.

Suggestion:

 * Copyright (c) 1998, 2026, Oracle and/or its affiliates. All rights reserved.

-------------

Changes requested by mhaessig (Committer).

PR Review: https://git.openjdk.org/jdk/pull/28581#pullrequestreview-3728810358
PR Review Comment: https://git.openjdk.org/jdk/pull/28581#discussion_r2746683181
PR Review Comment: https://git.openjdk.org/jdk/pull/28581#discussion_r2746682501
PR Review Comment: https://git.openjdk.org/jdk/pull/28581#discussion_r2746680565