PS: you may then be able to get rid of the call to `coreBindsSize` in `SimplCore`. If so, that would be good: faster compilation! Worth
#13426: compile-time memory-usage regression for DynFlags between GHC 8.0 and GHC 8.2 -------------------------------------+------------------------------------- Reporter: hvr | Owner: rwbarton Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 8.1 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 rwbarton): There was actually a third required change which I had guessed at earlier, namely changing {{{#!hs simplExprF1 env (Case scrut bndr _ alts) cont = simplExprF env scrut (Select { sc_dup = NoDup, sc_bndr = bndr }}} to {{{#!hs simplExprF1 env (Case scrut bndr ty alts) cont = seqType ty `seq` simplExprF env scrut (Select { sc_dup = NoDup, sc_bndr = bndr }}} Alternatively, one can insert a `seqType` into `reallyRebuildCase`: {{{#!diff @@ -2222,7 +2223,7 @@ reallyRebuildCase env scrut case_bndr alts cont ; dflags <- getDynFlags ; let alts_ty' = contResultType dup_cont - ; case_expr <- seqType alts_ty' `seq` mkCase dflags scrut' case_bndr' alts_ty' alts' + ; case_expr <- mkCase dflags scrut' case_bndr' alts_ty' alts' }}} I don't understand specifically why these changes make any difference, especially the first one, where we were throwing away the `ty` field anyways. It must share structure with some other part of the program, but I'm not sure what. Replying to [comment:14 simonpj]: trying... it might I suppose show up another leak currently patched by `coreBindsSize`. Yes, I'll try that next as I have a good setup for finding leaks now. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13426#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler