>perl -MEncode -e"print encode 'UTF-8', qq{use utf8; my \$x='a\xE1axBy'; \$x =~ /(.*?)x(A*)y/; }" | perl
Malformed UTF-8 character (unexpected continuation byte 0xa1, with no preceding start byte) in pattern match (m//) at - line 1.

##</code><code>##

61 C3 A1 61 78 42 79

##</code><code>##

(?!)\x{2660}|

##</code><code>##

use utf8;
use open ':std', ':locale';

##</code><code>##

use utf8;
use open ':std', ':encoding(cp852)';