#8885: Add inline versions of clone array primops -------------------------------------+------------------------------------ Reporter: tibbe | Owner: simonmar Type: feature request | Status: patch Priority: normal | Milestone: Component: Compiler | Version: 7.9 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Comment (by tibbe): My intuition to use a pointer based copy loop instead of an index based loop seems to have been wrong. Changing the loop from: {{{ dst_p = dst + SIZEOF_StgMutArrPtrs; src_p = src + SIZEOF_StgMutArrPtrs + WDS(offset); while: if (n != 0) { n = n - 1; W_[dst_p] = W_[src_p]; dst_p = dst_p + WDS(1); src_p = src_p + WDS(1); goto while; } }}} to {{{ dst_p = dst + SIZEOF_StgMutArrPtrs; src_p = src + SIZEOF_StgMutArrPtrs + WDS(offset); i = 0; while: if (i < n) { W_[dst_p + i] = W_[src_p + i]; i = i + 1; goto while; } }}} improves performance on my benchmark (clone array of 17 elements) by 14%. Attached patch with this improvement. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8885#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler