logint(a,b) incorrect for large b with b > a

[trizen]

There seems to be an issue in logint(a,b) for large enough b, with b > a.

Example:

use 5.014;
use Math::Prime::Util;
use Math::Prime::Util::GMP;
say Math::Prime::Util::logint(54, ~0);        # outputs 1 (incorrect)
say Math::Prime::Util::GMP::logint(54, ~0);   # outputs 0 (correct)