#8472: Primitive string literals prevent optimization -------------------------------------+------------------------------------- Reporter: akio | Owner: gridaphobe Type: bug | Status: patch 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): Phab:D2554, Wiki Page: | Phab:D2605 -------------------------------------+------------------------------------- Comment (by Ben Gamari <ben@…>): In [changeset:"d49b2bb21691892ca6ac8f2403e31f2a5e53feb3/ghc" d49b2bb/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="d49b2bb21691892ca6ac8f2403e31f2a5e53feb3" Allow top-level string literals in Core (#8472) This commits relaxes the invariants of the Core syntax so that a top-level variable can be bound to a primitive string literal of type Addr#. This commit: * Relaxes the invatiants of the Core, and allows top-level bindings whose type is Addr# as long as their RHS is either a primitive string literal or another variable. * Allows the simplifier and the full-laziness transformer to float out primitive string literals to the top leve. * Introduces the new StgGenTopBinding type to accomodate top-level Addr# bindings. * Introduces a new type of labels in the object code, with the suffix "_bytes", for exported top-level Addr# bindings. * Makes some built-in rules more robust. This was necessary to keep them functional after the above changes. This is a continuation of D2554. Rebasing notes: This had two slightly suspicious performance regressions: * T12425: bytes allocated regressed by roughly 5% * T4029: bytes allocated regressed by a bit over 1% * T13035: bytes allocated regressed by a bit over 5% These deserve additional investigation. Rebased by: bgamari. Test Plan: ./validate --slow Reviewers: goldfire, trofi, simonmar, simonpj, austin, hvr, bgamari Reviewed By: trofi, simonpj, bgamari Subscribers: trofi, simonpj, gridaphobe, thomie Differential Revision: https://phabricator.haskell.org/D2605 GHC Trac Issues: #8472 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8472#comment:20> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler