#14201: Implement ideas from "Compiling Pattern Matching to Good Decision Trees" -------------------------------------+------------------------------------- Reporter: AndreasK | Owner: AndreasK Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by AndreasK): I added rudimentary support for Records and made it work nicely with -XStrict. After playing around with nofib a lot I have essentially given up using it as a primary benchmarking tool I tried using nofib to benchmark (compile times) for #14524 which was inconclusive even when the performance difference for the function in question was ~10%. Running nofib with my changes didn't really produce results for the same issue of variance drowning out any difference the results would have made. == So my plan for now is: * Ditch nofib for the time being. * Create micro benchmarks and use criterion to check the difference. * Once I feel i have a reasonably sized set of benchmarks: * Look for pattern matching heavy real world examples and benchmark these. Based on the results of the OCaml implementation I don't expect measurable results unless there are not trivial patterns in a inner loop. * Gather feedback if gain/complexity trade off warrants inclusion in GHC. * Depending on the outcome of the above stop working on this or tidy up my code and get it into HEAD. == Micro Benchmarks: I mirror them on [https://github.com/AndreasPK/pattern_benchmarks Github]. Here is a [https://cdn.rawgit.com/AndreasPK/pattern_benchmarks/31dd3321/results/res_noi... result] for two simple patterns. I've uploaded the results also as attachment if GH becomes unavailable. (criterion_log) The two patterns I started with (each once used with enums once with Int) are at worst as fast and at best ~15% faster. (But then 15% of little is still not much). -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14201#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler