RFR: 8370502: C2: segfault while adding node to IGVN worklist [v2]

[Tobias Hartmann]

On Thu, 20 Nov 2025 16:40:49 GMT, Kerem Kat <krk at openjdk.org> wrote:

>> Do not try to replace `fallthrough_memproj` when it is null, fixes crash.
>> 
>> Test case is simplified from the ticket. Verified that the case crashes without the fix.
>
> Kerem Kat has updated the pull request incrementally with three additional commits since the last revision:
> 
>  - fix test spacing
>  - Update src/hotspot/share/opto/macro.cpp
>    
>    Co-authored-by: Manuel Hässig <manuel at haessig.org>
>  - Update src/hotspot/share/opto/macro.cpp
>    
>    Co-authored-by: Manuel Hässig <manuel at haessig.org>

Also, +1 to Dean's question. We need a better understanding of how we ended up in this situation.

test/hotspot/jtreg/compiler/c2/Test8370502.java line 34:

> 32: package compiler.c2;
> 33: 
> 34: public class Test8370502 {

Drive-by comment: Please rename the test to something more descriptive. We don't use bug numbers for test names anymore.

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PR Comment: https://git.openjdk.org/jdk/pull/28432#issuecomment-3561938940
PR Review Comment: https://git.openjdk.org/jdk/pull/28432#discussion_r2548916456