#15717: Performance regression in for_ alternatives from GHC 8.2.2 to newer GHCs -------------------------------------+------------------------------------- Reporter: nh2 | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Compiler | Version: 8.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Doubling sounds bad. There are 9 tests in the repro case. 've lost track of what is what. If someone was able to distil out a simple before-and-after on one test, that would be helpful. Better still, get some insight into what is happening. Thanks! -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15717#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler