RFR: 8277882: New subnode ideal optimization: converting "c0 - (x + c1)" into "(c0 - c1) - x" [v4]

Wed Dec 1 13:57:27 UTC 2021

On Tue, 30 Nov 2021 22:44:59 GMT, Zang, Zhiqiang <duke at openjdk.java.net> wrote:

>> Suggest two new optimizations that can be done in SubINode::Ideal.
>
> Zang, Zhiqiang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   add ok_to_convert to the condition.

I think this could be merged with the transformation on line 216 (the one converts "x - (y+c0)" into "(x-y) - c0")  and doing a branch on the constness of `in1` to determine the appropriate term of `in2` to do the transformation.

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PR: https://git.openjdk.java.net/jdk/pull/6441