#5113: Huge performance regression of 7.0.2, 7.0.3 and HEAD over 7.0.1 and 6.12 (MonoLocalBinds) -------------------------------------+------------------------------------- Reporter: | Owner: daniel.is.fischer | Status: closed Type: bug | Milestone: Priority: normal | Version: 7.0.3 Component: Compiler | Keywords: Resolution: fixed | performance, MonoLocalBinds Operating System: Linux | Architecture: x86 Type of failure: Runtime | Test Case: performance bug | perf/should_run/T5113 Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by bgamari): It seems to me like the fix for #10527 is a bit questionable. I may be missing something but I don't see how arguments could possibly get to the rebuilder (which is responsible for trying rewrite rules) as we now simply perform a bunch of substitutions on them with `substExprS` instead of passing them to`simplExpr`. Surely I'm missing something as one would think this would result in massive a performance regression if it really were the case. Simon, perhaps you can explain how you intended this to work? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/5113#comment:11 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler