#9279: Local wrapper function remains in final program; result = extra closure allocation -------------------------------------+------------------------------------- Reporter: simonmar | Owner: simonpj Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Resolution: | Keywords: LateLamLift Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by sgraf): Here's a diff that handles all `UnliftedRep`s uniformly: {{{ diff --git a/compiler/basicTypes/Literal.hs b/compiler/basicTypes/Literal.hs index 21f4a92290..0e9f25f51e 100644 --- a/compiler/basicTypes/Literal.hs +++ b/compiler/basicTypes/Literal.hs @@ -62,6 +62,7 @@ import Binary import Constants import DynFlags import Platform +import RepType import UniqFM import Util @@ -614,11 +615,14 @@ literalType (LitNumber _ _ t) = t absentLiteralOf :: TyCon -> Maybe Literal -- Return a literal of the appropriate primitive -- TyCon, to use as a placeholder when it doesn't matter -absentLiteralOf tc = lookupUFM absent_lits (tyConName tc) +absentLiteralOf tc + | tyConPrimRep tc == [UnliftedRep] + = ASSERT (isUnliftedTyCon tc) Just MachNullAddr + | otherwise + = lookupUFM absent_lits (tyConName tc) absent_lits :: UniqFM Literal -absent_lits = listToUFM [ (addrPrimTyConKey, MachNullAddr) - , (charPrimTyConKey, MachChar 'x') +absent_lits = listToUFM [ (charPrimTyConKey, MachChar 'x') , (intPrimTyConKey, mkMachIntUnchecked 0) , (int64PrimTyConKey, mkMachInt64Unchecked 0) , (wordPrimTyConKey, mkMachWordUnchecked 0) }}} But now `MachNullAddr` isn't always a literal of type `Addr#`. In particular, the definition {{{ -- | Find the Haskell 'Type' the literal occupies literalType :: Literal -> Type literalType MachNullAddr = addrPrimTy literalType (MachChar _) = charPrimTy literalType (MachStr _) = addrPrimTy }}} is probably a lie. But then it also lies for `MachStr` and `MachLabel`s, so maybe this isn't such a bad thing? The binding should be immediately eliminated by the simplifier, after all. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9279#comment:15 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler