On Wed, Mar 19, 2008 at 05:31:08PM +0000, Ian Lynagh wrote:
On Tue, Mar 18, 2008 at 04:12:35PM -0000, GHC wrote:
(don't worry, this often catches me out too. Perhaps a strict let should be indicated more explicitly in `-ddump-simpl`).
I'd certainly find it useful if it was clearer.
In fact, simpl hides more than I'd realised. With these definitions: f :: Integer -> Integer -> Integer -> Integer f x y z | y == 1 = x * z | otherwise = f (x * x) y (z * z) g :: Integer -> Integer -> Integer -> Integer g x y z | y == 1 = x | otherwise = g (x * x) y (z * z) simpl shows B.f (GHC.Num.timesInteger x_a5B x_a5B) y_a5D (GHC.Num.timesInteger z_a5F z_a5F); and B.g (GHC.Num.timesInteger x_a74 x_a74) y_a76 (GHC.Num.timesInteger z_a78 z_a78); for the recursive calls, although in the STG you can see that the multiplication of z is done strictly in f but not g (which is correct, as g is not strict in z). So perhaps the solution is just that I should look at the STG rather than the simpl when I want to see what's going on. Thanks Ian