Perl> $loop = 1; $counter = 0; 
cmpthese -1, { 
    and=>sub{ for(1..$loop){ ++$counter & 1 and 1 } }, 
    mod=>sub{ for(1..$loop){ ++$counter % 2 and 1 } } 
};;
        Rate mod and
mod 517876/s  -- -2%
and 525790/s  2%  --

Perl> $loop = 10; $counter = 0; 
cmpthese -1, { 
    and=>sub{ for(1..$loop){ ++$counter & 1 and 1 } }, 
    mod=>sub{ for(1..$loop){ ++$counter % 2 and 1 } } 
};;
        Rate mod and
mod 229555/s  -- -7%
and 245513/s  7%  --

Perl> $loop = 100; $counter = 0; 
cmpthese -1, { 
    and=>sub{ for(1..$loop){ ++$counter & 1 and 1 } }, 
    mod=>sub{ for(1..$loop){ ++$counter % 2 and 1 } } 
};;
       Rate mod and
mod 35041/s  -- -6%
and 37118/s  6%  --

Perl> $loop = 1000; $counter = 0; 
cmpthese -1, { 
    and=>sub{ for(1..$loop){ ++$counter & 1 and 1 } }, 
    mod=>sub{ for(1..$loop){ ++$counter % 2 and 1 } } 
};;
      Rate mod and
mod 3641/s  -- -7%
and 3931/s  8%  --

Perl> $loop = 1000; $counter = 0; 
cmpthese -1, { 
    and=>sub{ for(1..$loop){ ++$counter & 1 and 1 } }, 
    mod=>sub{ for(1..$loop){ ++$counter % 2 and 1 } } 
};;
      Rate mod and
mod 3725/s  -- -7%
and 3989/s  7%  --