Function expr_eq

scripts/config/expr.c:252–303

* Returns true if 'e1' and 'e2' are equal, after minor simplification. Two * &&/|| expressions are considered equal if every operand in one expression * equals some operand in the other (operands do not need to appear in the same * order), recursively. */

 * order), recursively.
 */
int expr_eq(struct expr *e1, struct expr *e2)
{
	int res, old_count;

	/*
	 * A NULL expr is taken to be yes, but there's also a different way to
	 * represent yes. expr_is_yes() checks for either representation.
	 */
	if (!e1 || !e2)
		return expr_is_yes(e1) && expr_is_yes(e2);

	if (e1->type != e2->type)
		return 0;
	switch (e1->type) {
	case E_EQUAL:
	case E_GEQ:
	case E_GTH:
	case E_LEQ:
	case E_LTH:
	case E_UNEQUAL:
		return e1->left.sym == e2->left.sym && e1->right.sym == e2->right.sym;
	case E_SYMBOL:
		return e1->left.sym == e2->left.sym;
	case E_NOT:
		return expr_eq(e1->left.expr, e2->left.expr);
	case E_AND:
	case E_OR:
		e1 = expr_copy(e1);
		e2 = expr_copy(e2);
		old_count = trans_count;
		expr_eliminate_eq(&e1, &e2);
		res = (e1->type == E_SYMBOL && e2->type == E_SYMBOL &&
		       e1->left.sym == e2->left.sym);
		expr_free(e1);
		expr_free(e2);
		trans_count = old_count;
		return res;
	case E_LIST:
	case E_RANGE:
	case E_NONE:
		/* panic */;
	}

	if (DEBUG_EXPR) {
		expr_fprint(e1, stdout);
		printf(" = ");
		expr_fprint(e2, stdout);
		printf(" ?\n");
	}

	return 0;
}

/*
 * Recursively performs the following simplifications in-place (as well as the