RFR: 8319372: C2 compilation fails with "Bad immediate dominator info" [v2]

[Christian Hagedorn]

On Thu, 30 Nov 2023 08:08:29 GMT, Roland Westrelin <roland at openjdk.org> wrote:

> > Sounds good. I think I will do that and also file a new bug to re-link all of the duplicates of JDK-8275202 to it. Then we could revert it back to an RFE which I think it should be if you agree (it was just a nice side effect that it also fixed the linked bugs).
> 
> Sounds good to me. Thanks.

I filed [JDK-8321097](https://bugs.openjdk.org/browse/JDK-8321097) as an umbrella bug and re-linked all the bugs from JDK-8275202 and turned it back into an RFE. I've walked through all the linked bugs and as suspected, the patch of this PR fixes the remaining (known) failing cases. I therefore closed JDK-8321097 again as "Not an Issue" (anymore). I found three additional test cases that were still failing but are now fixed with this patch. I'm planning to add them as separate test cases with [JDK-8321107](https://bugs.openjdk.org/browse/JDK-8321107).


> > > Additionally, we might want to investigate separately at some point if this patch allows us to relax some of the constraints of `try_sink_out_of_loop()` which we added fix these kind of issues with `CastII` nodes. I'm not sure though how much benefit it will bring.
> > 
> > 
> > This too makes sense to me.
> 
> I will file an additional RFE while at it.

Filed [JDK-8321109](https://bugs.openjdk.org/browse/JDK-8321109) to keep track of that.

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PR Comment: https://git.openjdk.org/jdk/pull/16844#issuecomment-1833798188