Makes sense to me
First off, they probably realize that they need to retain their top talent to stay in business. So they can't afford to be too shabby with the pay for too long, or that talent will bleed away.
Second, this year-long temporary pay cut has already given them two major benefits - one, it gave them a one-time injection of cash in the form of the pay cuts themselves. Second, this will effectively mean that the employees at AMD will go 2 years without a raise - the year they had a paycut, and the year their paycut was rescinded. This lowers the base pay of every employee at AMD; even in the future, when raises are calculated, they will likely be based on current pay - which will lack those two prior raises.
So, AMD still saved a lot of money with this maneuver, yet by sticking to their word and reversing the paycuts, they come out looking like good guys. All in all, rather slick.