Ooooh this is like that

  for {
     a[i] = something;
     b[i] = something;
     c[i] = a[i] + b[i]; // can only do a and b at the same time because c depends on them
  }


  // handle a[0],b[0]
  for {
    a[i] = something; 
    b[i] = something;
    c[i-1] = a[i-1] + b[i-1]; // can do all 3 at the same time because no deps.
  }

  // handle c[last]

optimization I saw in a talk about how CPUs can do many instructions at once if they don't depend on each other.

I was unaware of how something like this could play into game engines at the loop level, thanks for the link I'll watch it asap.