6879921 fix a case where it the superword optimization was attempting to handle arrays of oops which we didn't allow.  A guard was inserted in stmts_can_pack which fixed the original issue.  Testing with bigapps has shown that there are other paths where this problem can manifest.  In particular this pattern:

    public static void init(Object src[], boolean[] dst) {
        // initialize the arrays                                                                                                                      
        for (int i =0; i<src.length; i++) {
            dst[i] = src[i] != null ? false : true;
        }
    }

shows that are_adjacent_refs can be reached through est_savings, skipping the added is_java_primitive guard.  The fix is to move the is_java_primitive into are_adjacent_refs to guard the data_size calls.