RFR: JDK-8323190: Segfault during deoptimization of C2-compiled code [v3]

[Christian Hagedorn]

On Wed, 10 Jan 2024 18:20:42 GMT, Cesar Soares Lucas <cslucas at openjdk.org> wrote:

>> Currently, if `ReduceAllocationMerges` reduces an allocation merge that is used as a monitor C2 will SIGFAULT in `Process_OopMap_Node` because it's missing code to handle that case.  This patch fixes C2 to properly handle reduced allocation merges that are used as monitors. 
>> 
>> Tested with Linux x86_64 hotspot_all.
>
> Cesar Soares Lucas has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Convert NULL to nullptr. Remove type cast.

Update looks good, thanks.

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Marked as reviewed by chagedorn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17333#pullrequestreview-1814889165