RFR: 8256438: AArch64: Implement match rules with ROR shift register value [v3]

[Eric Liu]

On Tue, 23 Feb 2021 08:03:20 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> Hi Roland,
>> 
>> Thanks for your feedback.
>> 
>>> Even though existing code in that method seems to assume node's inputs can't be NULL, it's a good practice to protect against unexpected NULLs as that can happen when sub-graphs die during IGVN. So in(1)->in(1), in(1)->in(2), in(2)->in(2) need to be tested for NULL.
>> 
>> Agree
>> 
>>> That logic and the one for AddLNode are almost identical. So it would be good to have it in a shared method. I've been adding helper methods to make that possible but not all of that code is in yet.
>> 
>> As this match rule is trivial enough, how about withdrawing these shared code in this PR for integrating backend first if your helper methods coming soon?  
>> 
>>> Could you file a bug to revisit this issue later and assign it to me?
>> 
>> Okay, it's on my queue now:P
>> 
>> 
>> -- Eric
>
>> As this match rule is trivial enough, how about withdrawing these shared code in this PR for integrating backend first if your helper methods coming soon?
> 
> https://github.com/openjdk/jdk/pull/2045 is the one I'm referring to. No idea when it's going to get in so I would suggest to move forward with the current change and revisit it later.

Got it. The patch has been updated.

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PR: https://git.openjdk.java.net/jdk/pull/1858