On 07-Jun-1999, S.D.Mechveliani <[EMAIL PROTECTED]> wrote:
> One more question on the program simplification and `bottom'.
>
> People say, that the transformations like x - x -> 0 :: Integer
> are hardly ever applicable, because x may occur `undefined'.
This issue was already resolved -- someone already mentioned the solution.
But obviously you missed it, so let me restate the answer: instead of
using the transformation
x - x ==> 0
you should use the transformation
x - x ==> x `seq` 0
> Probably, the compiler can prove "defined" very often.
Indeed. It can then simplify things further, using the rule
x `seq` e ==> e if x is not _|_
--
Fergus Henderson <[EMAIL PROTECTED]> | "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh> | of excellence is a lethal habit"
PGP: finger [EMAIL PROTECTED] | -- the last words of T. S. Garp.
