That business about uninitialized values being used to seed RNGs threw me for a loop as well. I think it's safe to say that x ^= x is equivalent to x = 0 and o

That business about uninitialized values being used to seed RNGs threw me for a loop as well. I think it's safe to say that x ^= x is equivalent to x = 0 and optimize it that way, just like compilers recognize common idioms for e.g. swapping, counting set bits, etc and emit the correct intrinsic instructions.