Bug with math.log

[Dio Darkclainer <darkclainer@...>]

Hello all!
Code:

for i=1,20 do
   if math.floor(math.log(2^i,2)) ~= i then
      print(i)
   end
end

will be output
3
6
12
13

if use math.log(2^i)/math.log(2) intstead all work correctly
lua 5.2.3