RFR: 8343068: C2: CastX2P Ideal transformation not always applied [v2]

[Tobias Hartmann]

On Fri, 25 Oct 2024 15:09:50 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> The transformation:
>> 
>> 
>> (CastX2P (AddL base i)) -> (AddP (CastX2P base) i) 
>> 
>> 
>> when i fits in an int is not always applied: when the type of `i` is
>> narrowed so it fits in an int, the `CastX2P` is not enqueued for
>> igvn. This can get in the way of vectorization as shown by test case
>> `test2`.
>
> Roland Westrelin has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix test

Shouldn't this be caught by `VerifyIterativeGVN` after [JDK-8298952 ](https://bugs.openjdk.org/browse/JDK-8298952)?

-------------

PR Review: https://git.openjdk.org/jdk/pull/21714#pullrequestreview-2398042097