RFR: 8371558: C2: Missing optimization opportunity in AbsNode::Ideal [v2]

[Benoît Maillard]

On Wed, 12 Nov 2025 06:45:45 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

>> Benoît Maillard has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Update test/hotspot/jtreg/compiler/c2/TestMissingOptAbsZeroMinusX.java
>>   
>>   Co-authored-by: Tobias Hartmann <tobias.hartmann at oracle.com>
>
> test/hotspot/jtreg/compiler/c2/TestMissingOptAbsZeroMinusX.java line 30:
> 
>> 28:  *          This test ensures that updates to the Sub node’s inputs propagate as
>> 29:  *          expected and that the optimization is not missed.
>> 30:  * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-TieredCompilation -Xbatch -Xcomp
> 
> Suggestion:
> 
>  * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-TieredCompilation -Xcomp
> 
> 
> `-Xcomp` implies `-Xbatch`

I always forget about this one, thanks for pointing it out. Updated my notes as well.

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

PR Review Comment: https://git.openjdk.org/jdk/pull/28237#discussion_r2517260055