RFR: 8299658: C1 compilation crashes in LinearScan::resolve_exception_edge

[Lutz Schmidt]

On Fri, 18 Aug 2023 20:17:52 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> This is a quick fix for the C1 problem described in the JBS issue.
> When we find an illegal operand (modelled by nullptr) while resolving an exception edge we can propagate this state to the phi function and skip the edge.
> 
> If somebody finds a better way to propagate the "illegal" state to the phi function, I can change or close this PR.
> 
> Please review. A nice regression test would be a good thing, but probably not easy to write.

Looks reasonable.
For sure you can't continue if from_value isn't a valid operand.

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Marked as reviewed by lucy (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15348#pullrequestreview-1597155658