#11095: -O0 -g slows GHC down on list literals (compared to -O0 without -g) -------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): phab:D3001 Wiki Page: | -------------------------------------+------------------------------------- Comment (by dfeuer): Unfortunately, part of niteria's change was semantically invalid and needed to be reverted. I'm trying to understand a little more of what's going on around it that makes it a hot spot. niteria's observation that we almost always reach the `otherwise` suggests that perhaps we can find a quicker way to get there (rather than checking if each contains the other immediately, first find a way to discover or approximate that they certainly don't). But working out the asymptotic problems will surely be more important than that. Right now I'm struggling a bit to understand what `mkTick` is doing and how. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11095#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler