Hacker News new | ask | show | jobs
by tinus_hn 1793 days ago
That looks weird, why would you need to test if two values are equal if you’re going to assign them to be equal anyway?
1 comments

That is the trick.

In the happy path you are not assigning(`node=next`).

It is taken care of by `node++`, which removes the loop dependency and the processor can use the full instruction level parallelism.

It looks like a bug. The unhappy path contains both `node++` and `node=node->next`. Note that this is in the code following "Let’s go back to the code we showed for value speculation in C:", which is actually different from the preceding code it's supposed to be a copy of. I guess it's a typo.
The author has fixed this discrepancy now.
It looks as if the difference is in delaying the check for next == NULL.