#12545: Compilation time/space regression in GHC 8.0/8.1 (search in type-level lists and -O) -------------------------------------+------------------------------------- Reporter: | Owner: (none) mikhail.vorozhtsov | Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Inlining 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: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): A sizable chunk of the regression came from commit 6746549772c5cc0ac66c0fce562f297f4d4b80a2 (Add kind equalities to GHC.) {{{ Commit 6e56ac58a6905197412d58e32792a04a63b94d7e (Fix infix record field fixity (#11167 and #11173).) ----- $ time ghc4/inplace/bin/ghc-stage2 -fforce-recomp -O -c -Rghc-timing TypeList.hs Regression.hs <<ghc: 19608856112 bytes, 2265 GCs, 63045253/234165360 avg/max bytes residency (19 samples), 498M in use, 0.001 INIT (0.001 elapsed), 9.087 MUT (9.117 elapsed), 3.649 GC (3.647 elapsed) :ghc>> real 0m12.829s user 0m12.688s sys 0m0.140s Commit 6746549772c5cc0ac66c0fce562f297f4d4b80a2 (Add kind equalities to GHC.) ----- $ time ghc4/inplace/bin/ghc-stage2 -fforce-recomp -O -c -Rghc-timing TypeList.hs Regression.hs <<ghc: 68214058248 bytes, 5147 GCs, 71712416/267022672 avg/max bytes residency (20 samples), 586M in use, 0.001 INIT (0.001 elapsed), 29.850 MUT (29.871 elapsed), 4.806 GC (4.804 elapsed) :ghc>> real 0m34.744s user 0m34.572s sys 0m0.176s }}} But that's not the full story, since I get a realtime of `1m12.849s` with GHC 8.0.1. I'll try to figure out what other commit(s) are contributing. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12545#comment:8> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler