[jdk25u-dev] RFR: 8370502: C2: segfault while adding node to IGVN worklist

[Goetz Lindenmaier]

On Mon, 23 Feb 2026 16:17:13 GMT, Ozan Çetin <duke at openjdk.org> wrote:

> Backporting JDK-8370502: C2: segfault while adding node to IGVN worklist. 
> 
> This PR backports a fix for a C2 segmentation fault that occurs when expanding an UnlockNode with a null memory projection. The fix adds a necessary null check to ensure fallthrough_memproj is valid before attempting to replace it in the IGVN worklist.
> 
> make run-test TEST=tier1
> make run-test TEST=hotspot_compiler 
> make run-test TEST=test/hotspot/jtreg/compiler/c2/TestUnlockNodeNullMemprof.java 
> 
> Results: 
> [hotspot_compiler_report.html](https://github.com/user-attachments/files/25494824/hotspot_compiler_report.html)
> [TestUnlockNodeNullMemprof_report.html](https://github.com/user-attachments/files/25494831/TestUnlockNodeNullMemprof_report.html)

Hi @0zzy0sbourne 
please backport to 26 first. removing the label in the meantime.

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PR Comment: https://git.openjdk.org/jdk25u-dev/pull/304#issuecomment-3953230489