#6135: Unboxed Booleans ---------------------------------+------------------------------------------ Reporter: benl | Owner: jstolarek Type: feature request | Status: patch Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.4.1 Keywords: | Os: Unknown/Multiple Architecture: Unknown/Multiple | Failure: None/Unknown Difficulty: Unknown | Testcase: Blockedby: | Blocking: Related: #605 | ---------------------------------+------------------------------------------ Comment(by jstolarek): Following Ben's idea I created a proof-of-concept filter function using the new primops: {{{ filterN :: Vector Int -> Vector Int filterN vec = runST $ do let !size = length vec fVec <- unsafeNew size let put i x = do let !(I# v) = x inc = I# (v .>=# 0#) unsafeWrite fVec i x return $ i + inc fSize <- foldM' put 0 vec unsafeFreeze $ unsafeSlice 0 fSize fVec }}} Benchmarking with criterion shows that this function is 60% faster than the filter function based on stream fusion (tested for unboxed vectors containing 10 thousand and 10 million elements). Full code available [http://hackage.haskell.org/trac/ghc/wiki/PrimBool at the wiki page]. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/6135#comment:29 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler