MH compilation is broken in valhalla(mvt branch) build

David Simms david.simms at oracle.com
Mon Jun 19 08:05:50 UTC 2017


Thanks for reporting this Sergey, I filed a "mvt" labelled bug for tracking:

https://bugs.openjdk.java.net/browse/JDK-8182453

Cheers
/David Simms

On 17/06/17 01:13, Sergey Kuksenko wrote:
> I found that in valhalla build (mvt branch) MH compilation is broken 
> if MH is stored in non-final field. Cost of MH invocation is increased 
> ~100x times.
>
> Benchmark sources and compiled jar file could be found:
> http://cr.openjdk.java.net/~skuksenko/valhalla/mh_issue/
>
> Results:
> * on Java9 & Java8
>
> Benchmark            Mode  Cnt  Score   Error  Units
> XMH.walkFinal        avgt    5  4.500 ± 0.276  ns/op
> XMH.walkNonFinal  avgt    5  4.856 ± 0.011  ns/op
>
> * on MVT
> Benchmark            Mode  Cnt    Score    Error  Units
> XMH.walkFinal        avgt    5    4.406 ±  0.016  ns/op
> XMH.walkNonFinal  avgt    5  457.484 ± 10.550  ns/op
>
> These benchmarks are Java8 compatible and doesn't contain any Q-types.
>
> Besides, Vladimir told me that:
>
> > I briefly looked into the benchmarks and it seems the difference is 
> caused by a compiler bug: there are no compilations happening for 
> stand-alone lambda forms with Q-types.
> > So, when inlining doesn't happen, the Q-typed LF code stays 
> interpreted forever.
>
> Maybe that issues are related. Also I'd like to ask is infinite 
> interpreting of Q-types LF code known behavior? If yes, are there any 
> estimations when Q-types LF will be compiled?




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