#13536: Program which terminates instantly in GHC 8.0.2 runs for minutes with 8.2.1 -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: patch Priority: highest | Milestone: 8.2.1 Component: Compiler | Version: 8.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D3437 Wiki Page: | -------------------------------------+------------------------------------- Comment (by Joachim Breitner <mail@…>): In [changeset:"b55f310d06b8d3988d40aaccc0ff13601ee52b84/ghc" b55f310d/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="b55f310d06b8d3988d40aaccc0ff13601ee52b84" StgCse: Do not re-use trivial case scrutinees as they might be marked as one-shot, and suddenly we’d evaluate them multiple times. This came up in #13536 (test cases included). The solution was layed out by SPJ in ticket:13536#comment:12. Differential Revision: https://phabricator.haskell.org/D3437 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13536#comment:19> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler