#14727: Unboxed sum performance surprisingly poor -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.2.2 Resolution: | Keywords: UnboxedSums Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by osa1): I'd make sure `lookup` is inlined, in which case allocations should be reduced. OTOH you use one more register to return two values in `lookup#` instead of one as before so that may make some things worse. It'd be helpful to see benchmark code's Cmm for both versions (with `lookup` inlined in the unboxed sums version). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14727#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler