RFR: 8320128: Clean up Parse constructor for OSR [v2]

[Xin Liu]

On Tue, 21 Nov 2023 06:00:29 GMT, Xin Liu <xliu at openjdk.org> wrote:

>> There's a special case for the constructor of Parse. If current compilation is OSR and it is handling the top-level method(depth() == 1), then
>> 
>> 1. _tf = C->tf();
>> 2. _entry_bci = C->entry_bci();
>> 3. _flow = method()->get_osr_flow_analysis(_entry_bci);
>> 
>> We don't need to assign those member data twice. We can also factor out _flow->failing() for the special case and normal cases. 
>> 
>> It's worth mentioning that we can't save ciTypeFlow computation because
>> get_osr_flow_analysis(_entry_bci) actually needs get_flow_analysis(method()).
>
> Xin Liu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update according to reviewer's feedback.

okay. I see 'find_subtree_from_root(C->ilt(), caller, parse_method))' update C->ilt(). 
but I still have question about 1 and 2.  Because is_osr_parse() is always false, I make it simple.

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PR Comment: https://git.openjdk.org/jdk/pull/16669#issuecomment-1821333601