+/*
+ * Rewrites the expressions 'ep1' and 'ep2' to remove operands common to both.
+ * Example reductions:
+ *
+ * ep1: A && B -> ep1: y
+ * ep2: A && B && C -> ep2: C
+ *
+ * ep1: A || B -> ep1: n
+ * ep2: A || B || C -> ep2: C
+ *
+ * ep1: A && (B && FOO) -> ep1: FOO
+ * ep2: (BAR && B) && A -> ep2: BAR
+ *
+ * ep1: A && (B || C) -> ep1: y
+ * ep2: (C || B) && A -> ep2: y
+ *
+ * Comparisons are done between all operands at the same "level" of && or ||.
+ * For example, in the expression 'e1 && (e2 || e3) && (e4 || e5)', the
+ * following operands will be compared:
+ *
+ * - 'e1', 'e2 || e3', and 'e4 || e5', against each other
+ * - e2 against e3
+ * - e4 against e5
+ *
+ * Parentheses are irrelevant within a single level. 'e1 && (e2 && e3)' and
+ * '(e1 && e2) && e3' are both a single level.
+ *
+ * See __expr_eliminate_eq() as well.
+ */