#12354: Word foldl' isn't optimized as well as Int foldl' -------------------------------------+------------------------------------- Reporter: kjslag | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: 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 bgamari):
Well you might hope that you could write `eftInt`, `eftIntFB` once, at type `a` and SPECIALISE them. That would save copying them manually.
Indeed, unfortunately this would require that `eftInt` be runtime- representationally polymorphic since `Word :: RuntimeRep WordRep` and `Int :: RuntimeRep IntRep`. This is a rather unfortunate limitation since we would like to ensure that the polymorphism is resolved at compile-time via inlining. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12354#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler