RFR: 8333393: PhaseCFG::insert_anti_dependences can fail to raise LCAs and to add necessary anti-dependence edges [v13]

[Roberto Castañeda Lozano]

On Mon, 10 Feb 2025 15:53:22 GMT, Daniel Lundén <dlunden at openjdk.org> wrote:

> It does look like the problematic memory subgraph results due to loop peeling

OK, that sounds promising! Maybe it is indeed possible to make peeling/cloning maintain our invariant right from the start, and hope (and verify) it is not broken by other transformations. Up to you whether to integrate this point fix and continue your investigation separately or wait until you have explored along this line before integration.

> Sounds like a great idea, but I think we need to discuss the details further first. It is not quite clear to me yet what it is we want to assert.

Right, the details are not obvious to me either, it would probably require some exploration before we can formalize what it is exactly that we want to verify, since there is no specification (as far as I know) of what is expected for the memory subgraph in terms of liveness and interference.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22852#discussion_r1950405760