This doesn't seem to affect the problem, however.
Yes, I don’t think the problem in this particular case lies with `init`
I am curious if there is a way to manually force whatever's getting
#9345: Data.List.inits is extremely slow -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: Type: bug | Status: new Priority: high | Milestone: 7.8.4 Component: | Version: 7.8.3 libraries/base | Keywords: Resolution: | Architecture: Unknown/Multiple Operating System: | Difficulty: Easy (less than 1 Unknown/Multiple | hour) Type of failure: Runtime | Blocked By: performance bug | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by dfeuer): Replying to [comment:26 nomeata]: per se. I think it’s more like `concat`, but only when part of the recursion (the `c` above) is not inlined. That might also be what you observe. I hope you'll be able to tease this apart; `inits` isn't very important in the grand scheme of things, but `concat` is. the wrong arity to get the right one
Not with list fusion as we have it right now, I think. It should work
with https://github.com/takano-akio/ww-fusion (which I should follow up on again). That looks very interesting, by which I mean I couldn't understand it at all the first time around. I'll have to try again. If it can really solve this class of problem in a fairly thorough fashion, it will certainly be worth the added complexity.
I wonder if maybe the rule for `concat` can be rewritten so that the resulting recursion is nicer, but I don’t see it right now (but I’m too jetlagged to think anyways).
Rest well! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9345#comment:27 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler