struct expr *expr_extract_eq_or(struct expr **ep1, struct expr **ep2);
void expr_extract_eq(enum expr_type type, struct expr **ep, struct expr **ep1, struct expr **ep2);
struct expr *expr_trans_compare(struct expr *e, enum expr_type type, struct symbol *sym);
struct expr *expr_extract_eq_or(struct expr **ep1, struct expr **ep2);
void expr_extract_eq(enum expr_type type, struct expr **ep, struct expr **ep1, struct expr **ep2);
struct expr *expr_trans_compare(struct expr *e, enum expr_type type, struct symbol *sym);