Here is Gries Method example 1. Notice that triples sometimes are not emitted because they involve redundant expressions.

D = D + C * B;

A = D + C * B;

C = D + C * B;

Triple		valnum	c	d	redundant	optimized
(1)	* C B	3	n	y		* C B
(2)	+ D (1)	5	n	y		+ D (1)
(3)	= D (2)					= D (2)
(4)	* C B	3	n	n	(1)
(5)	+ D (4)	6	n	y		+ D (1)
(6)	= A (5)					= A (5)
(7)	* C B	3	n	n	(1)
(8)	+ D (7)	6	n	n	(5)
(9)	= C (8)					= C (5)

op	v1	v2
*	1	2
+	4	3
+	5	3

Avail Computations Table Symbol Table

triple valnum p A - 6

(1) * 1 2 3 B - 2

(2) + 4 3 5 C – 1 replaced by 6

(3) + 5 3 6 D – 4 replaced by 5

At end:

next i = 10

next v = 7

next p = 4