It would be great if we could have a test for this so we're sure this does not regress again. I looked at the repo and the code to reproduce
#9646: Simplifer non-determinism leading to 8 fold difference in run time performance -------------------------------------+------------------------------------- Reporter: erikd | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.10.1 Component: Compiler | Version: 7.8.3 Resolution: | Keywords: Operating System: Linux | Architecture: x86_64 Type of failure: Runtime | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by thomie): * status: closed => new * resolution: fixed => Comment: Replying to [comment:14 jstolarek]: this is pretty big. I wonder if it could be reduced further to include it in the testsuite. Good idea. Reopening. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9646#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler