> De: "John Rose" <john.r.r...@oracle.com> > À: "Remi Forax" <fo...@univ-mlv.fr> > Cc: "Karen Kinnear" <karen.kinn...@oracle.com>, "valhalla-spec-experts" > <valhalla-spec-experts@openjdk.java.net> > Envoyé: Jeudi 31 Janvier 2019 20:43:33 > Objet: Re: An example of substituability test that is recursive
> On Jan 31, 2019, at 10:41 AM, [ mailto:fo...@univ-mlv.fr | fo...@univ-mlv.fr ] > wrote: >> yes, i creates a DAG that will be too long to traverse :( >> you basically, DDOS yourself if you do a ==. > The complexity is exponential in depth, and > can be more than linear in heap allocation, > because of the risk of repeat traversals. > A worklist algorithm could make use of the > secret implementation identity of heap nodes > to push the complexity back down to heap > allocation size. A portable algorithm could > not. This is one more bit of evidence it should > be a system intrinsic rather than a vanilla library > function. yes, i buy that ! it will be always more expensive in Java, Rémi