#11226: Performance regression (involving sum, map, enumFromThenTo) -------------------------------------+------------------------------------- Reporter: j.waldmann | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- This program's performance suffers when compiled with 7.10, compared to 7.8: {{{ main = print $ sum $ map bitcount [0, 4 .. 2^24-1 ] bitcount :: Int -> Int bitcount x = if x > 0 then let (d,m) = divMod x 2 in bitcount d + m else 0 }}} See discussion in this thread: https://mail.haskell.org/pipermail/haskell- cafe/2015-December/122485.html -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11226 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler