#13253: Exponential compilation time with RWST & ReaderT stack with `-02` -------------------------------------+------------------------------------- Reporter: phadej | Owner: dfeuer Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.0.1 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 simonpj): Questions * Are those `perf/compiler` improvements happening because (a) GHC is generating less code of (b) GHC's code is running faster? * Is compilation generally faster, or are those two cases exceptional? (The testsuite only reports changes when they break through a threshold.) * Where are the gains in `mate` and the losses in `gameteb`? (Use `-ticky` to see.) I'd like to be sure that the loss in `gameteb` isn't for some silly reason that could readily be fixed. Fundamentally this change looks good, but I don't want to commit it and forget it because I'd like to understand the reasons a bit better. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13253#comment:25 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler