RFR: 8222029: Optimize Math.floorMod

Joe Darcy joe.darcy at oracle.com
Tue Apr 9 16:02:53 UTC 2019

Basically I'm inquiring about whether the existing tests provide at 
least as good code coverage on the new implementation as the old one. As 
it is a relatively simple method, perhaps it there is full coverage 
before and after. However, at times changing the implementation requires 
updates to the tests to includes different cases to check and I wanted 
to make sure that was looked at here.



On 4/9/2019 5:32 AM, Claes Redestad wrote:
> I think those tests cover all interesting corner cases, so the only way
> I see it can be improved is to make it more exhaustive (say generate a
> large random sample of tests every run). Do you feel that is needed?
> /Claes
> On 2019-04-09 01:35, Joseph D. Darcy wrote:
>> Should any additional cases be added to 
>> test/jdk/java/lang/Math/DivModTests.java to cover the new 
>> implementation?
>> Thanks,
>> -Joe
>> On 4/5/2019 10:21 AM, Claes Redestad wrote:
>>> On 2019-04-05 17:41, Andrew Haley wrote:
>>>> On 4/5/19 2:44 PM, Claes Redestad wrote:
>>>>> Testing: tier1-2, all Math tests run locally, -prof perfasm 
>>>>> verification
>>>>> on the provided microbenchmark.
>>>> Looks good.
>>> Thanks!
>>>> I've kicked the tyres on AArch64, and it looks like a useful 
>>>> optimization. The
>>>> gains when the divisor is constant (a common case) are modest but 
>>>> worthwhile.
>>> Thanks for trying it out and glad to hear it helps on AArch64 as well.
>>> /Claes

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