Re: Just tested it
Yeah and then the CPU optimizer kills your loop dead because it just doesn't do anything
So make it do something. Personally I think instead of hardcoding the two values to be added, I'd just call rand a couple of times and shift/xor those values to the total, and then just store the total (which is meaningless) alongside each real seed value.
As long as they're stored outside of this function and accessed somewhere else, the optimiser should leave those values and the code that generates them alone. Tricking optimisers isn't usually that difficult. (The hard part is tricking them into doing what you want them to do.)