When we use array(bool) instead of array(byte) in sieve 1899 benchmark we have performance drop.
java -jar millfork.jar --version
millfork version 0.3.18
java -jar $HOME/Programs/Millfork/millfork.jar -Xr -t a8 sieve1899.mfk
less is better
586 jiffies - array(byte)
680 jiffies - array(bool)
Millfork-sieve1899.zip