#9132: takeWhile&C. still not fusible -------------------------------------+------------------------------------- Reporter: Blaisorblade | Owner: skeuchel Type: bug | Status: patch Priority: normal | Milestone: Component: libraries/base | Version: 7.8.2 Resolution: | Keywords: fusion Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: Runtime | Difficulty: Moderate (less performance bug | than a day) Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------- Comment (by Blaisorblade): Thanks for taking care of this! The performance changes make sense to me, especially to fft2 which does use takeWhile. (I saw them on one OS X desktop, which however seemed to like suspending and had more stable timing; I didn't see them on a Linux machine which was otherwise more stable). On the regression, I agree it seems accidental. I'm confused that s1 and s2 are not joined by CSE. Delite/LMS, for instance, uses hash consing to prevent such programs from being formed in memory (the second definition is in a nested scope, but it seems this should not be a problem here). But I guess CSE in GHC would break programs using IO after the definition of IO is inlined. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9132#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler