#7258: Compiling DynFlags is jolly slow -------------------------------------+------------------------------------- Reporter: simonpj | Owner: simonpj Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.1 Resolution: | Keywords: deriving-perf 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 alexbiehl): Tobias, I had a quick glimpse over CmmSink and [https://github.com/ghc/ghc/blob/master/compiler/cmm/CmmSink.hs#L409 `skipped`] looks suspicious: For every assignment `l = e` which is not sunk `l` is [https://github.com/ghc/ghc/blob/master/compiler/cmm/CmmSink.hs#L409 consed] to `skipped`. And for each assignment `l = e` is checked a) is it element of sink and b) is there any register in skipped mentioned in `e`: {{{ cannot_inline = skipped `regsUsedIn` rhs -- Note [dependent assignments] || l `elem` skipped || not (okToInline dflags rhs node) }}} Considering the amount of code generated this might be a thing. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/7258#comment:60 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler