#9557: Deriving instances is slow -------------------------------------+------------------------------------- Reporter: Feuerbach | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: | Architecture: Unknown/Multiple Unknown/Multiple | Difficulty: Unknown Type of failure: | Blocked By: None/Unknown | Related Tickets: #8731 Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- Comment (by simonpj): It undoubtedly is a bit unexpected if simply adding `deriving( Show )` or whatever, which seems such a little thing, generates seriously large amounts of object code. If someone feels able to investigate I would suggest: * Find out if any particular class is to blame. How much of the code is generated by which classes? * Study the generated code to see if it could be abstracted, so that instead of lots of code, there were calls to some suitable shared functions. Obviously there is a performance/code-size issue to worry about, but my guess is that while `Eq` and `Ord` might be performance-critical, `Read` and `Show` are not. But it would require some thoughtful investigation. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9557#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler