RFR: 8348562: ZGC: segmentation fault due to missing node type check in barrier elision analysis

[Roberto Castañeda Lozano]

On Mon, 27 Jan 2025 06:59:34 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

> I guess it is pretty unlikely but I'd like to make sure that we don't miss an actual allocation because the pattern is a little bit different on ppc.

Hi Richard, note that  `compiler/gcbarriers/TestG1BarrierGeneration.java` passes on PPC64 after applying [JDK-8346280](https://bugs.openjdk.org/browse/JDK-8346280) ([under review](https://github.com/openjdk/jdk/pull/23235)), implying that `is_allocation` is successful on PPC64 at least for the most common allocation scenarios.
I also tried running the optimization tests in `compiler/gcbarriers/TestZGCBarrierElision.java` (currently only enabled for x64 and aarch64) on PPC64, and test cases that rely on `is_allocation` finding an allocation (such as `testAllocateThenStore`) pass. There are some failures, but I suspect they are due to other factors (e.g. ADL instruction naming mismatches). If you want to study the effectiveness of the barrier elision optimization on PPC64, I suggest to address these failures and enable `compiler/gcbarriers/TestZGCBarrierElision.java` for PPC64 as well.

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PR Comment: https://git.openjdk.org/jdk/pull/23295#issuecomment-2615195440