#15703: Significant compilation time blowup when refactoring singletons-heavy code -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.8.1 Component: Compiler | Version: 8.6.1 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: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): I built this code using a profiled GHC 8.6.1. Here are the highlights: {{{ Wed Oct 3 22:18 2018 Time and Allocation Profiling Report (Final) ghc-stage2 +RTS -p -RTS -B/u/rgscott/Software/ghc4/inplace/lib -O1 -fforce-recomp Lib.hs total time = 276.05 secs (276053 ticks @ 1000 us, 1 processor) total alloc = 403,405,509,720 bytes (excludes profiling overheads) COST CENTRE MODULE SRC %time %alloc simplCast-simplCoercion Simplify compiler/simplCore/Simplify.hs:1248:57-77 75.8 76.8 substTyWith TyCoRep compiler/types/TyCoRep.hs:(2213,23)-(2214,50) 23.8 23.0 }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15703#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler