Simon,
On Thu, 2006-11-30 at 02:13 +0000, Simon Peyton-Jones wrote:
> | A related problem is
> |
> | foo :: Int -> Int -> Int
> | foo 0 n = 0
> | foo m n = foo (m-n) n
> | Here, n isn't getting unboxed although it could be if m is not 0 in the
> first iteration. Perhaps unrolling
> | the loop once could help here.
>
> I'm not sure when I fixed this, but it's working fine now. Try it!
Not quite. For:
------
module Foo where
data a :*: b = !a :*: !b
infixl 7 :*:
foo :: Int -> Int :*: Int -> Int
foo 0 _ = 0
foo i (m :*: n) | even i = foo (i-m) (m :*: n)
| otherwise = foo (i-n) (m :*: n)
------
I get
------
$wfoo :: Int# -> (:*:) Int Int -> Int#
$wfoo =
\ (ww_spE :: Int#) (w_spG :: (:*:) Int Int) ->
case ww_spE of ds_Xi7 {
__DEFAULT ->
case w_spG of wild_Xc { :*: m_a7E n_a7F ->
case remInt# ds_Xi7 2 of wild1_aoo {
__DEFAULT ->
case n_a7F of wild11_aoS { I# y_aoU ->
$wfoo
(-# ds_Xi7 y_aoU)
(case m_a7E of tpl_Xt { I# ipv_sp2 -> wild_Xc })
};
0 ->
case m_a7E of wild11_aoS { I# y_aoU ->
$wfoo
(-# ds_Xi7 y_aoU)
(case n_a7F of tpl_B2 { I# ipv_spb -> wild_Xc })
}
}
};
0 -> 0
}
------
I'm not entirely sure why my original example works now. Anyway, this is
a rather minor problem, at least for me.
Roman
_______________________________________________
Cvs-ghc mailing list
[EMAIL PROTECTED]
http://www.haskell.org/mailman/listinfo/cvs-ghc
