[lworld] RFR: 8367245: [lworld] C2 compilation fails with "Missed optimization opportunity in PhaseIterGVN"

[Marc Chevalier]

On Thu, 6 Nov 2025 11:17:58 GMT, Roland Westrelin <roland at openjdk.org> wrote:

> I think the rationale is that if we're seeing conflicting profile, there's a good chance profile data is inaccurate and we can as well ignore it.

That makes sense. It's more practical than ignoring it everywhere we use it when it's oddly too specific. Indeed, speculative types don't need to be sound (or complete), and they start with a (probably) unsound premise: profiling data. I wonder if we are implicitly expecting too much soundness from the speculative type in the verification process.

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PR Comment: https://git.openjdk.org/valhalla/pull/1717#issuecomment-3501882936