#!/usr/bin/perl

use strict;
use warnings;
use 5.010;

sub doit {
    my ($head, $body) = @_;
    $body =~ s/QUALIFIED// 
      unless $head ~~ /^\w+?clk\[\d\]/;
    $head . $body;
}

local $_ = do { local $/; scalar <DATA> };

s/ ^ \b ( [ \w \s \[ \] ]+ \s+ \( ) $ 
      ( .*? ^\)$ ) /doit $1, $2/gemsx;

print;

__END__

qclk[6] INPUT (
     ! "asdk fd  sasd"
     VALID ( 
       late_lead 3 ar qclk slope 20
       late_lead 3 af qclk slope 04
       early_dn 8 ar qclk slope 6
       early_up 6 af qclk slope 6
     )
     cext %0.00394757
     cmax %0.005504
     QUALIFIED
)
clkout_qclk_61[3] OUTPUT (
)
clkout_qclk_61[2] OUTPUT (
     REQUIRED ( 
       earlyp  0.5 br qclk clm(2)
       latel_up  5 bf qclk clk(2)
     )
     REQUIRED ( 
       early_lead_dn  0.004 bf qclk clkdom(2)
       late_trail_dn  0.005 br qclk clkdom(2)
     )
     cext %0.0647336
     max_ceff_up %0.187
     QUALIFIED
)