my @elem = map { int rand 1000 } 1..10000;

sub map_s {
   my @mod_sorted = sort { $a <=> $b } map { $_ % 2**6 } @elem;
}

sub for_s {
   my @a;
   for ( @elem )
   {
      push @a, $_ % 2**6;
   }
   my @mod_sorted = sort { $a <=> $b } @a;
}
__END__
      Rate for map
for 15.8/s  -- -4%
map 16.5/s  4%  --