Is it possible to move some of your length testing out of the regex? 
while ( /(simple_match)/ ) {
    $count++ if length($1) >= 6;
}

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regexes are hard, my results when I minimize their use have resulted in less maintainance than the times I built big fancy ones. But, sometimes there is no way around it.
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In reply to Re: Implementing variable-width negative lookbehind assertions? by Aighearach
in thread Implementing variable-width negative lookbehind assertions? by ToasterLeavings

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