- ghc-tickets - Haskell.org

Re: [GHC] #3767: SpecConstr for join points
by GHC 31 Mar '17

31 Mar '17

#3767: SpecConstr for join points -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 6.12.1 Resolution: | Keywords: SpecConstr 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: | -------------------------------------+------------------------------------- Changes (by simonpj): * keywords: => SpecConstr -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/3767#comment:14> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #2255: Improve SpecConstr for free variables
by GHC 31 Mar '17

31 Mar '17

#2255: Improve SpecConstr for free variables -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: ⊥ Component: Compiler | Version: 6.8.2 Resolution: | Keywords: SpecConstr 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: | -------------------------------------+------------------------------------- Changes (by simonpj): * keywords: => SpecConstr -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/2255#comment:5> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #4941: SpecConstr generates functions that do not use their arguments
by GHC 31 Mar '17

31 Mar '17

#4941: SpecConstr generates functions that do not use their arguments -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: task | Status: new Priority: normal | Milestone: ⊥ Component: Compiler | Version: 7.0.1 Resolution: | Keywords: SpecConstr 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: | -------------------------------------+------------------------------------- Changes (by mpickering): * keywords: => SpecConstr -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4941#comment:22> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #5059: Pragma to SPECIALISE on value arguments
by GHC 31 Mar '17

31 Mar '17

#5059: Pragma to SPECIALISE on value arguments -------------------------------------+------------------------------------- Reporter: batterseapower | Owner: (none) Type: feature request | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.0.3 Resolution: | Keywords: SpecConstr, | StaticArgumentTransformation 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: | -------------------------------------+------------------------------------- Changes (by mpickering): * keywords: => SpecConstr, StaticArgumentTransformation Comment: In comment:10 Max notes that SAT provides 20-30% wins in nofib, wow! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5059#comment:21> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #855: Improvements to SpecConstr
by GHC 31 Mar '17

31 Mar '17

#855: Improvements to SpecConstr -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: task | Status: new Priority: normal | Milestone: ⊥ Component: Compiler | Version: 6.4.2 Resolution: | Keywords: SpecConstr Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: N/A Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by mpickering): * keywords: => SpecConstr * cc: mpickering (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/855#comment:9> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #888: Implement the static argument transformation
by GHC 31 Mar '17

31 Mar '17

#888: Implement the static argument transformation -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: task | Status: new Priority: normal | Milestone: Component: Compiler | Version: 6.4.2 Resolution: | Keywords: | StaticArgumentTransformation Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: N/A Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by mpickering): * keywords: => StaticArgumentTransformation -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/888#comment:31> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

[GHC] #13502: Static argument transformation should also run after specialisation
by GHC 31 Mar '17

31 Mar '17

#13502: Static argument transformation should also run after specialisation -------------------------------------+------------------------------------- Reporter: mpickering | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Consider the following program where we eventually want `thepayload` to simplify to the same code as `direct`. {{{#!hs {-# LANGUAGE ExistentialQuantification, RankNTypes, DeriveFunctor #-} module Foo where newtype Q a b t = Q { getQ :: forall f . Applicative f => (a -> f b) -> f t } deriving Functor instance Applicative (Q a b) where pure a = Q (\_ -> pure a) (Q ab) <*> (Q a) = (Q (\v -> ab v <*> a v)) singleQ :: a -> Q a b b singleQ a = Q (\f -> f a) data L a = Nil | L a (L a) deriving Show traverseList :: Applicative f => (a -> f b) -> L a -> f (L b) traverseList f Nil = pure Nil traverseList f (L a la) = L <$> f a <*> traverseList f la newtype Identity a = Identity { runIdentity :: a } deriving (Functor, Show) instance Applicative Identity where pure = Identity (Identity f) <*> (Identity x) = Identity (f x) thepayload :: L String -> L String thepayload l = runIdentity $ (getQ $ (traverseList singleQ l)) Identity direct :: L String -> L String direct Nil = Nil direct (L a b) = L a b }}} With `ghc-8.0.2` and `-fstatic-argument-transformation`, the specialiser will specialise the call to `traverseList` and leave us with a definition like, {{{#!hs rec (20) $ssat_worker= λ sg sc l → case l of Nil→ pure sc Nil L a la → <*> sc (fmap ($p1Applicative sc) (L a)) ($ssat_worker sg sc la) (4) thepayload = λl→ $ssat_worker $fApplicativeIdentity l }}} `$ssat_worked` is recursive in `l` but not in the other two arguments so we can also apply SAT here. Notice that `$ssat_worker` is called with a statically known dictionary in `thepayload` and so if we can inline `$ssat_worker` we would get the same code as the naive `direct`, as desired. I verified that inserting another SAT pass later in the compilation pipeline does have the desired effect but am not sure where exactly the right place would be or whether it is in general desirable. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13502> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 4

Re: [GHC] #5539: GHC panic - Simplifier ticks exhausted
by GHC 31 Mar '17

31 Mar '17

#5539: GHC panic - Simplifier ticks exhausted -------------------------------------+------------------------------------- Reporter: hvr | Owner: simonpj Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.3 Resolution: | Keywords: Inlining Operating System: Linux | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash | Test Case: Blocked By: | Blocking: Related Tickets: #8613, #9070, | Differential Rev(s): #8319 | Wiki Page: | -------------------------------------+------------------------------------- Changes (by mpickering): * keywords: => Inlining Comment: This ticket is a bit of a mess but someone should test these examples again and make new tickets if they are still a problem. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5539#comment:64> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #5075: CPR optimisation for sum types if only one constructor is used
by GHC 31 Mar '17

31 Mar '17

#5075: CPR optimisation for sum types if only one constructor is used -------------------------------------+------------------------------------- Reporter: batterseapower | Owner: simonpj Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.0.3 Resolution: | Keywords: SpecConstr 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: | -------------------------------------+------------------------------------- Changes (by mpickering): * keywords: => SpecConstr -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5075#comment:27> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Re: [GHC] #7944: GHC goes into an apparently infinite loop at -O2
by GHC 31 Mar '17

31 Mar '17

#7944: GHC goes into an apparently infinite loop at -O2 -------------------------------------+------------------------------------- Reporter: bos | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Resolution: | Keywords: SpecConstr Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash | Test Case: Blocked By: | Blocking: Related Tickets: #5550 #8852 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by mpickering): * keywords: => SpecConstr -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7944#comment:11> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0