RFR: 8254317: C2: Resource consumption of ConvI2LNode::Ideal() grows exponentially [v2]

Thu Oct 22 16:33:33 UTC 2020

On Thu, 22 Oct 2020 09:03:33 GMT, Roberto Castañeda Lozano <rcastanedalo at openjdk.org> wrote:

>> Without -Xcomp, the final code would not the same as expected, lots of branches have been optimized with profiling data which we **do** normally used. 
>> 
>> I wonder whether it's feasible to create such a test case that grows exponentially with profiling data. I think that may decriable the issue more realistic.
>
> Thanks for the feedback! The goal of these test cases is to exercise the logic in `ConvI2LNode::Ideal()` in a way as isolated as possible from the rest of the JVM, for simplicity, reproducibility, and ease of debugging. I will rewrite them to verify the results outside the test method. I will see if I can get rid of `-Xcomp` and `-XX:CompileOnly` without making them too complex. If that does not work, I will try to construct another test case as suggested by @erik1iu .

I have addressed this in the latest update.

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PR: https://git.openjdk.java.net/jdk/pull/727