RFR: 8351568: Improve source code documentation for PhaseCFG::insert_anti_dependences [v2]

[Galder Zamarreño]

On Mon, 5 May 2025 09:02:30 GMT, Daniel Lundén <dlunden at openjdk.org> wrote:

>> Ah, good catch. Let me try to verify that my new asserts also trigger if I revert the fix for [JDK-8260420](https://bugs.openjdk.org/browse/JDK-8260420).
>
> Unfortunately, it was not straightforward to revert the fix for [JDK-8260420](https://bugs.openjdk.org/browse/JDK-8260420) (too many changes since then). If `!LCA_orig->dominates(pred_block) || early->dominates(pred_block)` failed at some point, then the new assert `early->dominates(LCA_orig)` must also fail in that situation (in theory). See the details in my other response above.

Ok, maybe I was not clear enough.

The comment says:

>     // Triggers an assert in PhaseCFG::raise_above_anti_dependences if loop strip mining verification is disabled:

My question is, does the test on top of which the comment is placed (`test4` right?) ever run with loop strip mining verification disabled and if it does, does the assert get triggered? If `test4` does not do this, seems to me it would be nice to have an additional test that verifies just that rather than accept/assume the comment as valid without a test that actually verifies this. Thoughts?

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

PR Review Comment: https://git.openjdk.org/jdk/pull/24926#discussion_r2075102963