You're not giving us enough information to help you much. (Please take a look at How (Not) To Ask A Question for pointers.)

Can you tell us, specifically, what the criteria are by which you detect whether $compare is "interesting" w.r.t. $element? Depending on the nature of the criteria, certain approaches may be dramatically better than others.

For example, if the criteria form a commutative relation over pairings of elements within @array, you can eliminate half of your tests by testing only the elements at positions i and j for array indices i<j:

    for (my $i = 0; $i < @array; $i++) {
        for (my $j = $i+1; $j < @array; $j++) {
            my ($element, $compare) = @array[$i,$j];
            # test $compare w.r.t. $element
        }
    }
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If your criteria form an ordering over the elements in your array, you might be able to perform all of your tests in linear time.

Cheers,
Tom