#2439: Missed optimisation with dictionaries and loops ---------------------------------+------------------------------------------ Reporter: rl | Owner: simonpj Type: bug | Status: new Priority: lowest | Milestone: 7.6.2 Component: Compiler | Version: 6.9 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: Runtime performance bug Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: | ---------------------------------+------------------------------------------ Comment(by simonpj): The `-fdicts-strict` flag exists but it has had no love for years, and I doubt it works right. One obstacle is that at the moment we implement a ''single-method'' type class with a newtype rather than a data type. We don't want to make that strict, lest we force the method rather than the dictionary. I rather think we sould remove the special case, so that all dictionaries are data types; then we could be uniformly strict. But we should do some bemchmarking to check that nothing slows down. Just awaiting someone with a bit of time and benchmarking bandwidth... Simon -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/2439#comment:17 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler