一个很急的问题

一个很急的问题
#!/usr/local/bin/perl
# -*- perl -*- Forces EMacs to use perl-mode

use Getopt::Std;

&getopts('s:o:');
if(!$opt_s || !$opt_o) {
  die "
pt_postprocessor.pl -s <input SDF file>
           -o <output SFD file>

$IN_FILE = $opt_s;
$OUT_FILE = $opt_o;

open(INPUT, $IN_FILE) ||
  die printf("Sorry, Could not open file %s\n",$IN_FILE);

open(OUTPUT, ">" . $OUT_FILE) ||
  die printf("Sorry, Could not open file %s\n",$OUT_FILE);

# this list describes the valid IOPATHS for each cell that has conditional
# path delays. All COND IOPATHS are not modified.


while (<INPUT>) {
  chop;
  @var = split;
#
# The following code strips out the unnecessary IOPATHS that are created by
# PrimeTime for cells with conditional path delays
#
  .....
  .....
  .....
#....表示省略的内容

  elsif ( ((@var[0] eq "(SETUP") || (@var[0] eq "(HOLD")) &&
       ((@var[2] eq "(posedge") || (@var[2] eq "(negedge")) ){
     @var[1]=~s/\\\[/\[/g;
     @var[1]=~s/\\\]/\]/g;
     printf OUTPUT "  %s (posedge %s) %s %s %s\n",@var[0],@var[1],@var

[2],@var[3],@var[4];
     printf OUTPUT "  %s (negedge %s) %s %s %s\n",@var[0],@var[1],@var

[2],@var[3],@var[4];
  }
#added by DDC group for transfering DC SDF file successful
#
  elsif(($_ ~= /Qx.x/) || ($_ ~= /Qx..x/) ||
     ($_ ~= /Ax.x/) || ($_ ~= /Ax..x/) ||
     ($_ ~= /Dx.x/) || ($_ ~= /Dx..x/))
  { $_ ~= s/xx/\[\]/g;
   printf OUTPUT "%s ", $_;   
  }
  else{
     $_=~s/\\\[/\[/g;
     $_=~s/\\\]/\]/g;
     printf OUTPUT "%s\n",$_;
  }
}

以上是perl程序的部分代码，而下面是我添加的，想表达的意思是把形如：Qx.x或者Qx..x等形式（如：Qx11x）的字符串变为Q[.]（如：Q[11]），编译报错。
elsif(($_ ~= /Qx.x/) || ($_ ~= /Qx..x/) ||
     ($_ ~= /Ax.x/) || ($_ ~= /Ax..x/) ||
     ($_ ~= /Dx.x/) || ($_ ~= /Dx..x/))
  { $_ ~= s/xx/\[\]/g;
   printf OUTPUT "%s ", $_;   
  }
很急，有没有达人能帮忙看看。