Deforesting edtiInt

Ian Lynagh igloo at
Sun Feb 3 12:31:54 EST 2008

Hi Robin,

On Thu, Jan 31, 2008 at 11:05:32PM +0000, Robin Houston wrote:
> Except that it is a lot slower than it needs to be. After digging
> around a bit, I suspected that the reason for this is that the general
> form of enumeration [from, then .. to] does not benefit from the
> deforestation optimisation.
> When I added some deforestation rules to GHC/Enum.lhs and rebuilt the
> library, I found my suspicion confirmed: after the change, my code
> runs roughly twice as fast.

Thanks for the patch! Looks good to me; I've applied it.


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