use Devel::Peek;
my $x = "abc";
Dump $x; # here $x is not magic
$x =~ /./g;
Dump $x; # now it is

##</code><code>##

#define tryAMAGICbin_MG(method, flags) STMT_START { \
	if ( ((SvFLAGS(TOPm1s)|SvFLAGS(TOPs)) & (SVf_ROK|SVs_GMG)) \
		&& Perl_try_amagic_bin(aTHX_ method, flags)) \
	    return NORMAL; \
    } STMT_END

##</code><code>##

my $x = 1; my $y = 2; my $z;
for (1..1000) {
    $z = $x + $y;
}