#14254: The Binary instance for TypeRep smells a bit expensive -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.2.1 Resolution: | Keywords: Typeable Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3998, Wiki Page: | Phab:D4078, Phab:D4082 -------------------------------------+------------------------------------- Changes (by dfeuer): * differential: Phab:D3998 => Phab:D3998, Phab:D4078, Phab:D4082 Comment: I believe the simplest thing right now that will actually make deserialization linear is Phab:D4082. If at some point GHC allows unlifted types in kinds (which Richard thinks is probably not hard), then it will get even simpler and even cheaper. Phab:D4078 implements Richard's idea of starting off by digging down to the constructor, and as a side effect reduces the number of tags needed to express deeply nested applications. But I very much doubt the complexity/benefit ratio supports that approach, unless we change the structure of `TypeRep` to match. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14254#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler