[jdk21u-dev] RFR: 8325494: C2: Broken graph after not skipping CastII node anymore for Assertion Predicates after JDK-8309902

[Tobias Hartmann]

On Thu, 20 Jun 2024 10:03:35 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> See: https://bugs.openjdk.org/browse/JDK-8325494?focusedId=14666187&#comment-14666187 :)
>> 
>> (I was just surprised this backport was "clean")
>
>> @shipilev: JDK 21 needs this fix (the included test shows it). The tests are passing when this fix is applied. I suggest to take it with the weakened assertion which is not relevant for fixing the issue. We can reactivate it when [JDK-8305636](https://bugs.openjdk.org/browse/JDK-8305636) gets backported (later release). Or do you have another proposal what to do with it?
> 
> Relaxing assert looks fine to me. It is unfortunate we have to do this, but alas. @TobiHartmann, is that what you folks did too?

@shipilev @TheRealMDoerr We (@chhagedorn) adjusted the assert like this:

`assert(((CastIINode*)init)->carry_dependency() && loop_head->skip_predicates() == init->in(0), "casted iv phi from pre loop expected");`

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PR Comment: https://git.openjdk.org/jdk21u-dev/pull/734#issuecomment-2186193186