RFR: 8367967: C2: "fatal error: Not monotonic" with Mod nodes [v2]

[Christian Hagedorn]

On Mon, 22 Sep 2025 21:40:47 GMT, Hannes Greule <hgreule at openjdk.org> wrote:

>> Generally, we shouldn't return a wider type (ZERO) if there is a later case that would return a more narrow type (TOP) for the same input types. If the inputs are widened and the first case doesn't match anymore but the later one still does, the result is not monotonic with the previous result.
>> 
>> Please review :)
>
> Hannes Greule has updated the pull request incrementally with one additional commit since the last revision:
> 
>   add a second @run

test/hotspot/jtreg/compiler/c2/TestModValueMonotonic.java line 1:

> 1: /*

Another thing: You could move this test to `compiler/ccp` which fits better than the generic `c2` folder.

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

PR Review Comment: https://git.openjdk.org/jdk/pull/27408#discussion_r2371467349