RFR: 8320649: C2: Optimize scoped values [v13]

[Roland Westrelin]

On Thu, 4 Apr 2024 12:57:46 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> src/hotspot/share/opto/callGenerator.cpp line 1218:
>> 
>>> 1216:     // slow_call:
>>> 1217:     // result = slowGet();
>>> 1218:     // goto continue;
>> 
>> Now you have duplication of these comments, see above `remove_first_probe_if_when_it_never_hits`. Would it make sense to put this somewhere more "central"?
>
> And you further repeat the comments below. I fear that if someone would eventually make changes, they would not update all comments, and then the comments diverge.

That one doesn't duplicate the one above `transform_get_subgraph()`. It's supposed to show what change was just made to the graph by `replace_current_exit_of_get_with_halt()`. Same for the one below, it's expected to show an incremental change. It's hard to show what changes without keeping the entire structure of the code I think.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16966#discussion_r1553627734