#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 Simon Peyton Jones <simonpj@…>): In [changeset:"f2ce86c2edc0840f5e731d5286a2a5e484263e3f/ghc" f2ce86c/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="f2ce86c2edc0840f5e731d5286a2a5e484263e3f" Do better sharing in the short-cut solver Trac #15164 showed that it sometimes really matters to share sub-proofs when solving constraints. Without it, we can get exponentialy bad behaviour. Fortunately, it's easily solved. Note [Shortcut try_solve_from_instance] explains. I did some minor assocaited refactoring. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15164#comment:18> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler