> each register's carry bits are independent from the ones that get carries added from the last register
No they're not. Let's say B's non-carry bits are all 1. If you carry anything from C, that will affect B's carry bits.
No they're not. Let's say B's non-carry bits are all 1. If you carry anything from C, that will affect B's carry bits.
It would be an incredibly rare case, so branch prediction will always get it right, and the cost of a branch nearly nill.