#8472: Primitive string literals prevent optimization -------------------------------------+------------------------------------- Reporter: akio | Owner: gridaphobe Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Resolution: | Keywords: newcomer Operating System: Linux | Architecture: x86_64 Type of failure: Runtime | (amd64) performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by gridaphobe): @akio sorry about the duplicate work! It looks like our patches are very similar, though I introduce a new StgRhs constructor rather than your StgTopBinding type. I think your approach is a bit better, as I end up having to deal with the (im)possibility of let-binding a literal anywhere (it looks like Stg uses `case <lit> of <var> { __DEFAULT -> ... }` to bind literals, which makes sense given that they can't be lazy). Does your patch validate? I just noticed this afternoon that although my patch works for the example and parts of nofib, it causes a linker error when building ghc-stage2, due to undefined symbols. I'm setting the label for the string literal a bit differently from you, so your patch might be fine. My CoreLint patch is at https://github.com/ghc/ghc/compare/master...gridaphobe:T8472#diff- 9ad7456ebf7fad38de8b24ddceb9bb3c. Do you want to submit your patch + my CoreLint pass, that ought to make for a complete patch :) (I also notice that both of our patches could use a nice Note explaining why we want to bind string literals at the top level, especially since the logic is spread across multiple phases of the compiler) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/8472#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler