I'd try a non-greedy quantifier... 
if ( $line =~ /[^a-zA-Z]$sub[^a-zA-Z]*?\(/ ) {

[download]
...and maybe a more generic subroutine finder... 
foreach my $line ( @sub_code ) 
{
    if ($line =~ /[^a-zA-Z]([a-zA-Z_]+[a-zA-Z_0-9]*)[^a-zA-Z]*\(/
        and exists $SUBS{$1}) 
    { push @subs, $key }
}

[download]

In reply to Re: Slow Regex - How to Optimize by Anonymous Monk
in thread Slow Regex - How to Optimize by noslenj123

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