c:\@Work\Perl>perl -wMstrict -MO=Deparse,-p -le
"my $line = qq{xyz\x80\x90\xa0abc};
 print qq{'$line'};
 ;;
 $line !~ s/[^[:ascii:]]//g;
 print qq{'$line'};
"
Useless use of negative pattern binding (!~) in void context at -e line 1.
BEGIN { $^W = 1; }
BEGIN { $/ = "\n"; $\ = "\n"; }
use strict 'refs';
(my $line = "xyz\200\220\240abc");
print("'${line}'");
(not ($line =~ s/[^[:ascii:]]//g));
print("'${line}'");
-e syntax OK