RFR: 8333393: PhaseCFG::insert_anti_dependences can fail to raise LCAs and to add necessary anti-dependence edges [v11]

[Quan Anh Mai]

On Thu, 30 Jan 2025 13:49:39 GMT, Daniel Lundén <dlunden at openjdk.org> wrote:

> initial_mem is always the earliest possible memory definition (m1, in this case).

This is a really bold assumption and I assume you do not have any concrete reason for it. "After" in the sense of CFG can only emerge after scheduling, while:

- We are scheduling.
- The load and its memory input have existed before scheduling, which makes it very hard to imagine that this is a valid assumption.

And "after" in the sense of graph edges seems not to be the case, either. As your example has pointed out.

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

PR Comment: https://git.openjdk.org/jdk/pull/22852#issuecomment-2624589169