#8766: length [Integer] is twice as slow but length [Int] is 10 times faster --------------------------------------------+------------------------------ Reporter: George | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.1-rc1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime performance bug | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: --------------------------------------------+------------------------------ Comment (by nomeata): Ok, with this change (i.e. a special `eftIntegerFB`) I get good results: Run time decreases from 16.3s in 7.6.3 to 11.7s in GHC HEAD. But if I use `-fno-call-arity` (Call arity analysis is not in 7.8), I still get 23s, which is still a regression over 16s, but better than the 30 I got with the unmodified library code. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8766#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler