Comment by ahartmetz

1 hour ago

You want to avoid branches in hot paths. If you branch inside the loop, lots of branches. If you branch outside the loop (into different specialized loops), few branches. Big fucking deal.

2 comments

ahartmetz

gpderetta 44 minutes ago

https://en.wikipedia.org/wiki/Loop_unswitching

econ 29 minutes ago

    bool w;
    int x[1000];
    int y[1000];
    for(int i=0;i<1000;i++){
      x[i] += y[i];
    }
    if(w){
      for(int i=0;i<1000;i++){
        y[i] = 0;
      }
    }

Slower but prettier with the if pushed down.