CUDA: Why are bitwise operators sometimes faster than logical operators?

Question

When I am down to squeezing the last bit of performance out of a kernel, I usually find that replacing the logical operators (&& and

Answer 1

A && B:

if (!A) {
  return 0;
}
if (!B) {
  return 0;
}
return 1;

A & B:

return A & B;

These are the semantics considering that evaluating A and B can have side effects (they can be functions that alter the state of the system when evaluated).

There are many ways that the compiler can optimize the A && B case, depending on the types of A and B and the context.