#9233: Compiler performance regression ---------------------------------+------------------------------------ Reporter: augustss | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: ---------------------------------+------------------------------------ Comment (by goldfire): I, too, have noticed that GHC has gotten slower to compile between 7.6.3 and 7.8.2. And, I have a nice file that demonstrates the slowness. First, 7.6.3: {{{ rae:10:40:52 ~/temp/th-desugar> ghc --version The Glorious Glasgow Haskell Compilation System, version 7.6.3 rae:10:43:47 ~/temp/th-desugar> time ghc Language/Haskell/TH/Desugar/Core.hs [1 of 2] Compiling Language.Haskell.TH.Desugar.Util ( Language/Haskell/TH/Desugar/Util.hs, Language/Haskell/TH/Desugar/Util.o ) [2 of 2] Compiling Language.Haskell.TH.Desugar.Core ( Language/Haskell/TH/Desugar/Core.hs, Language/Haskell/TH/Desugar/Core.o ) real 0m2.674s user 0m2.512s sys 0m0.131s rae:10:43:53 ~/temp/th-desugar> rm -f `find . -name '*.o' -or -name '*.hi' -or -name '*.dyn*'` rae:10:43:58 ~/temp/th-desugar> time ghc Language/Haskell/TH/Desugar/Core.hs -O2 [1 of 2] Compiling Language.Haskell.TH.Desugar.Util ( Language/Haskell/TH/Desugar/Util.hs, Language/Haskell/TH/Desugar/Util.o ) [2 of 2] Compiling Language.Haskell.TH.Desugar.Core ( Language/Haskell/TH/Desugar/Core.hs, Language/Haskell/TH/Desugar/Core.o ) real 0m9.089s user 0m8.648s sys 0m0.241s rae:10:44:13 ~/temp/th-desugar> rm -f `find . -name '*.o' -or -name '*.hi' -or -name '*.dyn*'` rae:10:44:17 ~/temp/th-desugar> time ghc Language/Haskell/TH/Desugar/Core.hs -O2 -fno-spec-constr [1 of 2] Compiling Language.Haskell.TH.Desugar.Util ( Language/Haskell/TH/Desugar/Util.hs, Language/Haskell/TH/Desugar/Util.o ) [2 of 2] Compiling Language.Haskell.TH.Desugar.Core ( Language/Haskell/TH/Desugar/Core.hs, Language/Haskell/TH/Desugar/Core.o ) real 0m9.351s user 0m8.180s sys 0m0.242s }}} Now, 7.8.2: {{{ rae:10:44:41 ~/temp/th-desugar> ghc --version The Glorious Glasgow Haskell Compilation System, version 7.8.2 rae:10:44:45 ~/temp/th-desugar> rm -f `find . -name '*.o' -or -name '*.hi' -or -name '*.dyn*'` rae:10:44:49 ~/temp/th-desugar> time ghc Language/Haskell/TH/Desugar/Core.hs [1 of 2] Compiling Language.Haskell.TH.Desugar.Util ( Language/Haskell/TH/Desugar/Util.hs, Language/Haskell/TH/Desugar/Util.o ) [2 of 2] Compiling Language.Haskell.TH.Desugar.Core ( Language/Haskell/TH/Desugar/Core.hs, Language/Haskell/TH/Desugar/Core.o ) real 1m5.906s user 0m7.972s sys 0m0.449s rae:10:45:58 ~/temp/th-desugar> rm -f `find . -name '*.o' -or -name '*.hi' -or -name '*.dyn*'` rae:10:46:05 ~/temp/th-desugar> time ghc Language/Haskell/TH/Desugar/Core.hs -O2 [1 of 2] Compiling Language.Haskell.TH.Desugar.Util ( Language/Haskell/TH/Desugar/Util.hs, Language/Haskell/TH/Desugar/Util.o ) [2 of 2] Compiling Language.Haskell.TH.Desugar.Core ( Language/Haskell/TH/Desugar/Core.hs, Language/Haskell/TH/Desugar/Core.o ) real 0m58.498s user 0m18.374s sys 0m0.566s rae:10:47:06 ~/temp/th-desugar> rm -f `find . -name '*.o' -or -name '*.hi' -or -name '*.dyn*'` rae:10:47:14 ~/temp/th-desugar> time ghc Language/Haskell/TH/Desugar/Core.hs -O2 -fno-spec-constr [1 of 2] Compiling Language.Haskell.TH.Desugar.Util ( Language/Haskell/TH/Desugar/Util.hs, Language/Haskell/TH/Desugar/Util.o ) [2 of 2] Compiling Language.Haskell.TH.Desugar.Core ( Language/Haskell/TH/Desugar/Core.hs, Language/Haskell/TH/Desugar/Core.o ) real 1m32.710s user 0m17.552s sys 0m0.637s }}} The relevant files are attached. I don't have data for it, but I've noticed that compiling these files in GHCi is relatively snappy. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9233#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler