RFR: 8325478: Restructure the macro expansion compiler phase to not include macro elimination [v2]

[Daniel Lundén]

On Tue, 17 Jun 2025 14:09:34 GMT, Saranya Natarajan <snatarajan at openjdk.org> wrote:

>> src/hotspot/share/opto/macro.cpp line 2482:
>> 
>>> 2480:     return;
>>> 2481:   }
>>> 2482:   refine_strip_mined_loop_macro_nodes();
>> 
>> This call is later compared to before, right? In the previous version of `expand_macro_nodes`, it ran before the call to `eliminate_macro_nodes`. Is it safe to move it in this way?
>
> This placement of ` refine_strip_mined_loop_macro_nodes()` is ok as it only affects the functionality in the loop of the `eliminate_opaque_looplimit_macro_nodes` method.

Could you elaborate a bit on why this is the case? Just looking briefly at `OuterStripMinedLoopNode::adjust_strip_mined_loop` (called from `refine_strip_mined_loop_macro_nodes`), I'm not convinced there are no other interactions.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25682#discussion_r2155032375