RFR: 8361140: Missing OptimizePtrCompare check in ConnectionGraph::reduce_phi_on_cmp [v4]

Guanqiang Han duke at openjdk.org
Fri Jul 11 07:39:41 UTC 2025


On Fri, 11 Jul 2025 07:22:23 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

>> Guanqiang Han 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 seven additional commits since the last revision:
>> 
>>  - Remove the unused variable
>>  - Merge remote-tracking branch 'upstream/master' into 8361140
>>  - update regression test
>>  - Merge remote-tracking branch 'upstream/master' into 8361140
>>  - update modification and add regression test
>>  - Merge remote-tracking branch 'upstream/master' into 8361140
>>  - 8361140: Missing OptimizePtrCompare check in ConnectionGraph::reduce_phi_on_cmp
>>    
>>    When running with `-XX:-OptimizePtrCompare` (which disables pointer comparison optimization), the compiler may hit an assertion failure in debug builds because `optimize_ptr_compare` is still being called. This violates the intended usage of the flag and leads to unexpected crashes.
>>    
>>    This patch adds an early return to `reduce_phi_on_cmp` when `OptimizePtrCompare` is false. Since the optimization relies on `optimize_ptr_compare` for static reasoning about comparisons, there's no benefit in proceeding with `reduce_phi_on_cmp` when this support is disabled.
>
> Looks good, thanks! I'll give this a spinning in our testing and report back again.

@chhagedorn @JohnTortugo Thanks again for all your feedback. It’s been very helpful! If possible, could you please run /sponsor?

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PR Comment: https://git.openjdk.org/jdk/pull/26125#issuecomment-3061047171


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