#13692: Constructors and such should be able to move around seq# sometimes -------------------------------------+------------------------------------- Reporter: dfeuer | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.2.1-rc2 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 simonpj): Good point. Is it a performance-critical point? Or just an observation. `seq#` seems poorly documented in GHC's source code. It should really be called `evaluate#` for a start. I think it's important that it is ''not'' strict because I think the idea is that no earlier code should evaluate its argument. I guess this transformation would be sound {{{ seq (case e of p -> r) s --> seq e s of (# s', v #) -> case v of p -> seq r s' }}} which I think is more or less what you are suggesting. I have no idea if it'd be worth it; but I suppose it could be if it removed allocation from some inner loop. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13692#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler