20.05.2019, 18:21, "Thiago Macieira" <[email protected]>: > On Monday, 20 May 2019 06:56:56 PDT Lars Knoll wrote: >> I actually think we should consider getting rid of shared_null and instead >> have d == nullptr as the null/default constructed state of the object. Yes, >> that means we need to check for d == nullptr in member functions, but I >> don’t think the overhead is a problem, as d will have to be loaded into a >> register in any case. > > It does introduce a compare-and-branch that wouldn't otherwise be there, but > the cost is minimal compared to what most API would be doing, indeed.
We should wrap d == nullptr in Q_UNLIKELY() to make branch predictor assume non-null path by default. -- Regards, Konstantin _______________________________________________ Development mailing list [email protected] https://lists.qt-project.org/listinfo/development
