RFR: 8320909: C2 compilation fails with "Missed optimization opportunity in PhaseIterGVN"

[Emanuel Peter]

On Tue, 22 Apr 2025 08:06:48 GMT, Marc Chevalier <mchevalier at openjdk.org> wrote:

> One could imagine an alternate solution that would not update the notification system
but rather the type system. On top of intervals, we could have some modulo information
and know that some value is 0 modulo 2^s, or alternatively, some bitwise information
that would know the lower s bits to be 0 (and the top bits to be unknown).

@marc-chevalier FYI: https://github.com/openjdk/jdk/pull/17508 this could be an alternative solution, at least once we fully follow that road. It tracks the "known bits", which would give you the "modulo information".

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PR Comment: https://git.openjdk.org/jdk/pull/24792#issuecomment-2820648102