I personally have run into exponential compile times with type families. Unfortunately I have not had the time yet to reduce my test case to something tractable.
Janek Dnia sobota, 29 listopada 2014, Dr. ERDI Gergo napisał: > Hi, > > Prompted by this question: > http://stackoverflow.com/questions/26538595/more-efficient-type-level-compu >tations-using-type-families I wrote some code today using closed type > families and datakinds. Also, as a baseline, I typechecked the code using > open type families from > the original question. > > The two files are here: > > https://gist.github.com/gergoerdi/727f028e4c1ed158ac9a > https://gist.github.com/gergoerdi/f96d1a9a58f5e3dccc18 > > On GHC 7.8.3, typechecking took about 45 seconds for each. However, on a > 'perf' build of GHC 7.9 d8c437b3, with ghc-stage2, the first one took 1m3s > and the second one 1m12s. A 40% and 60% increase in typechecking time, > respectively! > > Is this some known regression, something surprising, or is 'perf' simply > not the right build flavour for this kind of comparison? > > Bye, > Gergo > _______________________________________________ > ghc-devs mailing list > [email protected] > http://www.haskell.org/mailman/listinfo/ghc-devs _______________________________________________ ghc-devs mailing list [email protected] http://www.haskell.org/mailman/listinfo/ghc-devs
