#14865: GHC Defeats Manual Worker Wrapper with Unboxed Sum -------------------------------------+------------------------------------- Reporter: andrewthad | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.5 Resolution: | Keywords: UnboxedSums 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 simonpj): This is a classic difficulty. Given, say {{{ f x = g (...x...) }}} perhaps we could split `f` into two parts {{{ f x = g (f' x) f' x = ...x... }}} and then perhaps we can inline the (now small) `f`, perhaps to good effect. This is what you want to do here: you want {{{ findByte !off !len !w !arr = boxMaybeInt (go off) }}} to be inlined at every call site. It's be simple to arrange, by giving `len`, `w` and `arr` as extra arguments to `go`. But GHC just isn't clever enough to do that, unless you tell it to do so by hand, with an INLINE pragma. I don't really know how to fix this. But it's a good example. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14865#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler