This is all very puzzling. But when we get to the bottom of it we may speed up a key piece of infrastructure! So I think it's worth
#14880: GHC panic: updateRole -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Type | Version: 8.2.2 checker) | Resolution: | Keywords: TypeInType Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash or panic | Test Case: Blocked By: | Blocking: Related Tickets: #15076 | Differential Rev(s): Phab:D4769 Wiki Page: | -------------------------------------+------------------------------------- Comment (by tdammers): Replying to [comment:59 simonpj]: persevering.
1. Is `poly_merge` still high on the list in `ticky` in the accumulator
version? If so, why? As a matter of fact, no it's not. So it looks like the allocations we're winning from not using `poly_merge` as much just end up being eaten up elsewhere. Top 15 entries for the accumulator version: {{{ Entries Alloc Alloc'd Non-void Arguments STG Name -------------------------------------------------------------------------------- 2539473 107917008 0 3 i.M containers-0.5.11.0:Data.IntMap.Internal.$winsert{v r7O} (fun) 172005 90819296 0 5 EMMMS ghc:TcUnify.promoteTcType2{v r3m} (fun) 2330347 86853624 0 2 >L base:GHC.Base.map{v 01X} (fun) 699656 37268264 0 1 L go4{v sNmj} (ghc:TcMType) (fun) in r1Y 448802 35904160 0 7 E>>>>.M ghc:TcMType.$s$wmapType{v r1Y} (fun) 367181 23499584 0 2 LS ghc:TcRnMonad.traceTc1{v rlu} (fun) 887399 22625616 0 1 M go28{v sNmi} (ghc:TcMType) (fun) in r1Y 283135 21931488 0 4 >SSM ghc:TcHsSyn.$wzonkTyVarOcc{v r1F} (fun) 269137 18194264 0 1 L go13{v sSI0} (ghc:TcHsSyn) (fun) in rN 95951 16510560 0 2 >L base:Data.OldList.sortBy{v rD} (fun) 302653 16395904 0 5 +>LLL ghc:MonadUtils.zipWith3M{v rp} (fun) 194400 15552000 0 7 E>>>>.M ghc:TcHsSyn.$s$wmapType{v rN} (fun) 559499 15509096 0 1 M ghc:TcMType.zonkTcTyVar{v r1l} (fun) 138823 13706576 0 1 S sat_sMLW{v} (ghc:TcMType) (fun) in r6P 440463 11089080 0 1 S sat_sNmS{v} (ghc:TcMType) (fun) in sNmi }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14880#comment:62 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler