What about using a different kind of data structure like a map or similar
Of course that the first thing we should do, once we are convinced
#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): Replying to [comment:66 simonpj]: that's where the time is going! (We only ave suggestive evidence so far.) Small maps should be cheap; that's the business of the containers library. `LocalReg` is `Uniquable` so something like this should work: {{{ type LocalRegSet = UniqSet LocalReg emptyLocalRegSet :: LocalRegSet emptyLocalRegSet = emptyUniqSet nullLocalRegSet :: LocalRegSet -> Bool nullLocalRegSet = isEmptyUniqSet elemLocalRegSet :: LocalReg -> LocalRegSet -> Bool elemLocalRegSet = elementOfUniqSet insertLocalRegSet :: LocalRegSet -> LocalReg -> LocalRegSet insertLocalRegSet = addOneToUniqSet cannot_inline = skipped `regsUsedIn` rhs -- Note [dependent assignments] || l `elemLocalRegSet` skipped || not (okToInline dflags rhs node) regsUsedIn :: LocalRegSet -> CmmExpr -> Bool regsUsedIn ls _ | nullLocalRegSet ls = False regsUsedIn ls e = wrapRecExpf f e False where f (CmmReg (CmmLocal l)) _ | l `elemLocalRegSet` ls = True f (CmmRegOff (CmmLocal l) _) _ | l `elemLocalRegSet` ls = True f _ z = z }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/7258#comment:67 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler