#7436: Derived Foldable and Traversable instances become extremely inefficient due to eta-expansion --------------------------------------+------------------------------------- Reporter: shachaf | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.6.1 Resolution: fixed | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: Runtime performance bug | Difficulty: Unknown Testcase: perf/should_runt/T7436 | Blockedby: Blocking: | Related: --------------------------------------+------------------------------------- Changes (by simonpj):
* status: patch => closed * testcase: => perf/should_runt/T7436 * resolution: => fixed Comment: Also: {{{ commit 3d51f271e6819c52508956f2426c4c19dec0b2fb Author: Twan van Laarhoven <twa...@gmail.com> Date: Thu Jan 3 16:24:42 2013 +0100 Added note explaining the lambdas generated by functor deriving code, and how it compares to the old deriving code which used eta expansion. }}} Thanks for the patches! I added a test in `perf/should_run`. Interestingly the massive difference is run-time, not in allocation or residency. Simon -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7436#comment:17> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler _______________________________________________ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs