#14239: Let -fspecialise-aggressively respect NOINLINE (or NOSPECIALISABLE?) -------------------------------------+------------------------------------- Reporter: | Owner: (none) MikolajKonarski | Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 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: -------------------------------------+------------------------------------- First, let me explain the context. By defuault GHC specialises very few functions and the programmer is expected to enumerate additional functions to specialise (e.g., with INLINABLE). This is problematic if the functions are defined in libraries, not in the user code. Also, in some kinds of code it leads to INLINABLE on every functions (because missing even just one breaks the chain). The problems are described in other tickets. With `-fspecialise-aggressively` and `-fexpose-all-unfoldings`, the default is reversed. Everything (even functions from libraries, as long as they have unfoldings available) is specialized and the user only needs to enumerate exceptions. Unfortunately, he can't. I think (in particular from experiments with `-Wall-missed- specialisations`), in the presence of `-fexpose-all-unfoldings`, the `-fspecialise-aggressively` option happily specialises functions marked `NOINLINE` (and so with `Inline:,` in the .hi file). Consequently, the user has no way to be selective wrt specialisation when using the specialize-often default. If we want to gradually disentangle INLINE and SPECIALIZE (e.g., rename INLINABLE to SPECIALISABLE), perhaps the pragma to use should be NOSPECIALISABLE. Perhaps it also makes sense to leave the current functionality, for experimenting with whole modules, but I'd rename it to `-fforce-specialise-aggressively`, because it overrides the obvious user intent. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14239 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler