[Haskell-cafe] GHC optimisations

[Neil Mitchell]

Hi

> Its (==) isn't
> reflexive (is it transitive? probably, at least if there aren't too many
> optimizations, but floating-point transitive equality isn't very useful).

It's not even referentially transparent in all cases. a == b may fail
while the double's are in the high precision registers, and then
succeed later on in the program once they are truncated. I think you
have to specify -fexcess-precision with GHC to get this behaviour.

Thanks

Neil