RFR: 8351889: C2 crash: assertion failed: Base pointers must match (addp 344) [v2]

[Roland Westrelin]

On Thu, 2 Oct 2025 04:03:58 GMT, Dean Long <dlong at openjdk.org> wrote:

> What if we just relax the assert? I failed to figure out what this assert is protecting us from by looking at the code. So what happens in a product build or when this assert is commented out?

For this particular test case, nothing. The assert is right before the cast nodes are removed, anyway. Once they are removed, the `AddP` in the chain all have the same base input.
The risk, I think, is if some code that transforms a chain of `AddP`s (some time before the assert) wrongly assume they all have the same base.  It's also easier to write such a transformation if it's an invariant that a chain of `AddP`s have the same base (it's one less thing to worry about).

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PR Comment: https://git.openjdk.org/jdk/pull/25386#issuecomment-3360125566