RFR: 8333393: PhaseCFG::insert_anti_dependences can fail to raise LCAs and to add necessary anti-dependence edges [v10]

[Quan Anh Mai]

On Mon, 27 Jan 2025 11:33:07 GMT, Daniel Lundén <dlunden at openjdk.org> wrote:

>> Edit: We need to go down when iterating a memory node from below, too.

> I'm lost here as well.

It means for example we have:

     in
      |    \
      |        \
    1 Phi       2 Phi

Suppose `initial_mem` is `2 Phi`, we need to search for kills at `in` (go up, which means we reach `in` from below), then from `in` we go down to `1 Phi` and search for kills at it, too.

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PR Comment: https://git.openjdk.org/jdk/pull/22852#issuecomment-2615578547