#12357: Increasing maximum constraint tuple size significantly blows up compiler allocations -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 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): Wiki Page: | -------------------------------------+------------------------------------- Description changed by bgamari: @@ -5,1 +5,1 @@ - `real/fulsom/Shapes.hs` module regresses by 16% in both compiler + `real/fulsom/Shapes.hs` module regresses by around 15% in both compiler New description: In July 2015 (dd3080fe0263082f65bf2570f49189c277b12e28) the maximum constraint tuple size was raised from 16 to 62 to address #10451. It turns out that this change is apparently one of the larger compile-time regressions in recent GHC history. For instance, the nofib `real/fulsom/Shapes.hs` module regresses by around 15% in both compiler allocations and compile time. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12357#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler