#14594: 2 modules / 2500LOC takes nearly 3 minutes to build -------------------------------------+------------------------------------- Reporter: schyler | Owner: dfeuer Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by dfeuer): I have not as yet been able to find anything non-linear, but we seem to pay an awful lot ''per instance''. Given {{{#!hs data Foo7 = Foo7 (Int) deriving Data data Foo8 = Foo8 (Int) deriving Data -- plus 25 more like this }}} compiling with `-O` takes 5 seconds. The single most expensive part is codegen, which takes about a second, but otherwise no particular pass stands out as being particularly expensive. I experimentally tried deriving more of the `Data` methods to try to reduce simplification time. Unfortunately, I paid for it in typechecking time. I still want to check if ''some'' of those extra methods are worthwhile, but otherwise I really don't know. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14594#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler