RFR: 8365570: C2 fails assert(false) failed: Unexpected node in SuperWord truncation: CastII [v2]

[Christian Hagedorn]

On Tue, 6 Jan 2026 23:48:51 GMT, Jasmine Karthikeyan <jkarthikeyan at openjdk.org> wrote:

>> Yep, I can replicate the crash on the old commit with `TestFramework.runWithFlags("-Xcomp", "-XX:CompileCommand=compileonly,*TestSubwordTruncation::*");` instead of `@Warmup(0)`. I think this would also be a good option, as it would let you get coverage with Xcomp on the other tests as well.
>
> I've pushed a commit that changes the Warmup(0) to the second test run.

Given the timeout reported by Tobias, I would rather opt for `@Warmup(0)` with one `run()` only. We will eventually run the test with `-Xcomp` on higher tiers, for example at tier6, so we get `Xcomp` coverage at some point.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26827#discussion_r2668480186