private static boolean isTrue(ExprNodeDesc expr) {
    if (expr instanceof ExprNodeConstantDesc) {
      ExprNodeConstantDesc c = (ExprNodeConstantDesc) expr;
      if (Boolean.TRUE.equals(c.getValue())) {
        return true;
      }
    }
    return false;
  }
Checks wether the two expression sets have a common deterministic intersection.
ql/src/java/org/apache/hadoop/hive/ql/plan/ExprNodeDescUtils.java