Why jump to recursion? I don't see any reason for it in your post. Personally, I'd use a queue for this:

my @queue = (1, 2, 3, 4);
while (@queue) {
  my $current = shift @queue;
  next unless subA($current);
  push @queue, subB($current);
}
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(And don't get in the habit of prefixing your sub calls with &. It's not required in Perl 5+ and has side-effects that you probably don't expect.)