Posted on behalf of the original author. The new PRNG has already been committed in the wyhash GitHub repo.

static inline uint64_t w1rand(uint64_t s) { const uint64_t c = 0xd07ebc63274654c7ull; s += c; __uint128_t t = (__uint128_t)s (*s ^ c); return (t >> 64) ^ t; }