RFR: 8265132 : C2 compilation fails with assert "missing precedence edge" [v4]

[Jamsheed Mohammed C M]

On Fri, 18 Jun 2021 22:46:28 GMT, Dean Long <dlong at openjdk.org> wrote:

>> if LCA is above null block(ie. null_check block itself or above it) means it has uses in other places . for null_check block anti dependency will be taken care in implicit null logic. above it doesn't actually matter for our considering case i guess.
>> 
>> i kept dominate logic as it is more broad than equating with LCA (that means even if there are multiple basic blocks in null  path the assert holds good)
>
>> i kept dominate logic as it is more broad than equating with LCA (that means even if there are multiple basic blocks in null  path the assert holds good)
> 
> In that case, could you add a test case with multiple basic blocks in the null path?  It should crash without your dominates improvement.

I didn't say there is a case already. I just said it can even take care of that. problem with using LCA is the new fix has raised LCA, may be i should use LCA_Orig in second case. but do you see problem in using dominate in assert?

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PR: https://git.openjdk.java.net/jdk/pull/4200