bit sets in IntSet vs. Integer

[Henning Thielemann]

On Sat, 18 Jun 2016, Carter Schonwald wrote:

> Henning: I suggest you read the gmp source and tell us :)

I hoped you have already done so. :-)

Does GHC call GMP for bit operations on Integer?
Aha, yes, it calls integer_gmp_mpn_and_n for (.&.) :
    https://hackage.haskell.org/package/integer-gmp-1.0.0.1/docs/src/GHC.Integer.Type.html#c_mpn_and_n