Does it? I'm getting

4 is the biggest odd number
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for the very sample you gave. Maybe the second $z on line 26 should be $y ?

Update: Here's my solution. It first sorts the numbers, then finds the first odd one starting from the greatest one.

sub cmp3 {
    my ($x, $y, $z) = @_;
    ($y, $x) = ($x, $y) if $y < $x;
    ($z, $y) = ($y, $z) if $z < $y;
    ($y, $x) = ($x, $y) if $y < $x;
    if (1 == $z % 2) {
        return "$z is the biggest odd number\n"
    } elsif (1 == $y % 2) {
        return "$y is the biggest odd number\n"
    } elsif (1 == $x % 2) {
        return "$x is the biggest odd number\n"
    } else {
        return "All are even numbers\n"
    }
}
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Tested against yours with

for (1 .. 10000) {
    my ($x, $y, $z) = map int rand 20, 1 .. 3;
    my $orig = orig($x, $y, $z);
    my $cmp3 = cmp3($x, $y, $z);
    say "$x $y $z ($orig) [$cmp3]" if $orig ne $cmp3;
}
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($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
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