Very curious. It does indeed look as though the strictness analyser is confused; but it should certainly not be confused by mutual recursion. I'll definitely look into it. But don't hold your breath -- it's a very busy fortnight. Simon | -----Original Message----- | From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell-users-bounces@haskell.org] On | Behalf Of Neil Mitchell | Sent: 09 July 2007 23:14 | To: glasgow-haskell-users@haskell.org | Subject: Unexpected boxing in generated code | | Hi, | | I've got an inner loop that I think I can see is strict in the Int | argument being passed around, but that GHC 6.6.1 isn't unboxing. In | the following example both functions take a GHC.Base.Int, which I | think should be an Int#. | | Rec { | f60_rS5 :: GHC.Prim.State# GHC.Prim.RealWorld -> GHC.Base.Int -> GHC.Base.Int | [GlobalId] | [Arity 2 | NoCafRefs | Str: DmdType LL] | f60_rS5 = | \ (v1_aWH :: GHC.Prim.State# GHC.Prim.RealWorld) (v2_aWI :: GHC.Base.Int) -> | case $wccall_r2kv v1_aWH of wild_X2j { (# ds_d1V4, ds1_d1V3 #) -> | case ds1_d1V3 of wild1_X2L { | __DEFAULT -> f60_rS5 ds_d1V4 v2_aWI; | (-1) -> v2_aWI; | 10 -> f561_r2kx ds_d1V4 v2_aWI | } | } | f561_r2kx :: GHC.Prim.State# GHC.Prim.RealWorld -> GHC.Base.Int -> GHC.Base.Int | [GlobalId] | [Arity 2 | NoCafRefs | Str: DmdType LL] | f561_r2kx = | \ (v1_aWm :: GHC.Prim.State# GHC.Prim.RealWorld) (v2_aWn :: GHC.Base.Int) -> | case $wccall_r2kv v1_aWm of wild_X2j { (# ds_d1V4, ds1_d1V3 #) -> | case ds1_d1V3 of wild1_X2P { | __DEFAULT -> | case v2_aWn of wild2_a2du { GHC.Base.I# x_a2dw -> | case wild1_X2P of wild3_X35 { | __DEFAULT -> f60_rS5 ds_d1V4 (GHC.Base.I# (GHC.Prim.+# x_a2dw 1)); | 10 -> f561_r2kx ds_d1V4 (GHC.Base.I# (GHC.Prim.+# x_a2dw 1)) | } | }; | (-1) -> v2_aWn | } | } | end Rec } | | This code comes from a line counting program, I have attached the | entire source. My character counting program does infer the correct | strictness, although that is based on a single self-recursive | function. The largest obvious difference is that the strictness | depends on the two functions which call each other - does this impeed | GHC's strictness analysis? | | Thanks | | Neil