#9038: Foreign calls don't make their arguments look strict
-------------------------------------+------------------------------------
Reporter: tibbe | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 7.8.2
Resolution: | Keywords:
Operating System: Unknown/Multiple | Architecture: Unknown/Multiple
Type of failure: None/Unknown | Difficulty: Unknown
Test Case: | Blocked By:
Blocking: | Related Tickets: 1592
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Comment (by simonpj):
Are you sure? I get this:
{{{
simonpj@cam-05-unx:~/tmp$ ghc -c -O -ddump-simpl T9038.hs
==================== Tidy Core ====================
Result size of Tidy Core = {terms: 20, types: 28, coercions: 5}
T9038.f1
:: GHC.Types.Int
-> GHC.Prim.State# GHC.Prim.RealWorld
-> (# GHC.Prim.State# GHC.Prim.RealWorld, () #)
[GblId,
Arity=2,
Caf=NoCafRefs,
Str=DmdType ,
Unf=Unf{Src=InlineStable, TopLvl=True, Arity=2, Value=True,
ConLike=True, WorkFree=True, Expandable=True,
Guidance=ALWAYS_IF(unsat_ok=True,boring_ok=False)
Tmpl= \ (val_arX [Occ=Once!] :: GHC.Types.Int)
(eta_B1 [Occ=Once] :: GHC.Prim.State# GHC.Prim.RealWorld)
->
case val_arX of _ [Occ=Dead] { GHC.Types.I# ipv_sKN
[Occ=Once] ->
case {__pkg_ccall main function1 GHC.Prim.State#
GHC.Prim.RealWorld
-> (# GHC.Prim.State# GHC.Prim.RealWorld
#)}_dKB
eta_B1
of _ [Occ=Dead] { (# ds_dKz [Occ=Once] #) ->
case {__pkg_ccall main function2 GHC.Prim.Int#
-> GHC.Prim.State# GHC.Prim.RealWorld
-> (# GHC.Prim.State# GHC.Prim.RealWorld
#)}_dKx
ipv_sKN ds_dKz
of _ [Occ=Dead] { (# ds1_dKv [Occ=Once] #) ->
(# ds1_dKv, GHC.Tuple.() #)
}
}
}}]
T9038.f1 =
\ (val_arX :: GHC.Types.Int)
(eta_B1 :: GHC.Prim.State# GHC.Prim.RealWorld) ->
case val_arX of _ [Occ=Dead] { GHC.Types.I# ipv_sKN ->
case {__pkg_ccall main function1 GHC.Prim.State# GHC.Prim.RealWorld
-> (# GHC.Prim.State# GHC.Prim.RealWorld
#)}_dKB
eta_B1
of _ [Occ=Dead] { (# ds_dKz #) ->
case {__pkg_ccall main function2 GHC.Prim.Int#
-> GHC.Prim.State# GHC.Prim.RealWorld
-> (# GHC.Prim.State# GHC.Prim.RealWorld
#)}_dKx
ipv_sKN ds_dKz
of _ [Occ=Dead] { (# ds1_dKv #) ->
(# ds1_dKv, GHC.Tuple.() #)
}
}
}
T9038.f :: GHC.Types.Int -> GHC.Types.IO ()
[GblId,
Arity=2,
Caf=NoCafRefs,
Str=DmdType ,
Unf=Unf{Src=InlineStable, TopLvl=True, Arity=0, Value=True,
ConLike=True, WorkFree=True, Expandable=True,
Guidance=ALWAYS_IF(unsat_ok=True,boring_ok=True)
Tmpl= T9038.f1
`cast` (_R -> Sym (GHC.Types.NTCo:IO[0]
<()>_R)
:: (GHC.Types.Int
-> GHC.Prim.State# GHC.Prim.RealWorld
-> (# GHC.Prim.State# GHC.Prim.RealWorld, ()
#))
~#
(GHC.Types.Int -> GHC.Types.IO ()))}]
T9038.f =
T9038.f1
`cast` (_R -> Sym (GHC.Types.NTCo:IO[0] <()>_R)
:: (GHC.Types.Int
-> GHC.Prim.State# GHC.Prim.RealWorld
-> (# GHC.Prim.State# GHC.Prim.RealWorld, () #))
~#
(GHC.Types.Int -> GHC.Types.IO ()))
simonpj@cam-05-unx:~/tmp$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 7.8.2
simonpj@cam-05-unx:~/tmp$ cat T9038.hs
{-# LANGUAGE BangPatterns #-}
module T9038 ( f ) where
f :: Int -> IO ()
f !val = do
cFunction1
cFunction2 val
foreign import ccall unsafe "function1" cFunction1 :: IO ()
foreign import ccall unsafe "function2" cFunction2 :: Int -> IO ()
}}}
So GHC has decided that the function is small enough to inline bodily
(rather than do w/w). But the inlining is there all right, and the
strictness info. I'm puzzled about why you get different results with GHC
7.8.2.
Simon
--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9038#comment:5
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler
