#12364: Demand analysis for sum types -------------------------------------+------------------------------------- Reporter: nomeata | Owner: Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by nomeata):
Currently if a call site looks like f (Just (p+q)) we'll build a thunk for p+q. But f always evaluates it, so that thunk is useless; we could use call-by-value.
Actually inlining would require strictness analysis, wouldn’t it? Extending that to sums might work, but I was looking into demand analysis right now. There, we would be able to turn the thunk into a non-updateable one. I’m sure I was not confusing it with CPR, but I guess in comment:3 I was thinking about let-up vs. let-down, and that some examples would look better if the analysis would work the other way. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12364#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler