* expr.h (jumpifnot_1, jumpif_1, do_jump_1): Declare.
* dojump.c (do_jump_by_parts_greater): Take two operands instead of
full expression.
(do_jump_by_parts_equality, do_compare_and_jump): Ditto.
(jumpifnot_1, jumpif_1): New wrappers for do_jump_1.
(do_jump): Split out code for simple binary comparisons into ...
(do_jump_1): ... this, taking the individual operands and code.
Change callers to helper function above accordingly.
* expr.c (expand_expr_real_1): Use jumpifnot_1 for simple binary
comparisons.