my @codes = qw/ CODE1 CODE2 CODE3 /;
my %hitCounts;
my @regex = map { $hitCounts{$_}=1; qr/$_/i } @codes;

# tune this parameter for optimal performance, balancing better ordering
# of regexen with sort costs...
my $resortFreq=1000;

my $iterCount=0;

while (my $inputline = <FILE>) {
    my $found = 0;
    foreach my $regex(@regex) {
        if ($inputline =~ /$regex/) {
            $hitCounts{$regex}++;
            $found = 1;
            last;
        }
    }
    # re-sort every 1000 lines.  The "1000" is a parameter that prolly should
    # be tuned
    if(++$iterCount%$resortFreq == 0) {
        @regex=sort {$hitCounts{$b}<=>$hitCounts{$a}} @regex;
    }
    next unless $found;
    # logic goes here
}

##</code><code>##

END {
   print "Regexen in sorted order:\n\t";
   print join "\n\t",sort {$hitCounts{$b}<=>$hitCounts{$a}} @regex;
   print "\n";
}