#15164: Slowdown in ghc compile times from GHC 8.0.2 to GHC 8.2.1 when doing Called arity analysis -------------------------------------+------------------------------------- Reporter: flip101 | Owner: (none) Type: bug | Status: new Priority: highest | Milestone: 8.6.1 Component: Compiler | Version: 8.2.1 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by nomeata): Call Arity does a fixed-point iteration for mutual recursive groups; if there is one giant, then I am not surprised to see that it explodes there. We could detect absurdly large groups and do some conservative approximation. But as Sebastian finds, there is *another*, independent regression that inflates the Core and compilation time (and blows it up in a way that completely chokes Call Arity)… -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15164#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler