Load a 64-bit element into the low bits of the vector and sets all other bits to zero.
This intrinsic is provided for completeness and is equivalent to
u64x2_replace_lane::<0>(u64x2(0, 0), *m) (which doesn’t require
This intrinsic is unsafe because it takes a raw pointer as an argument, and the pointer must be valid to load 8 bytes from. Note that there is no alignment requirement on this pointer since this intrinsic performs a 1-aligned load.