w1rand

[wangyi-fudan]

Hi,
wyrand has been updated to w1rand. faster, smaller:

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;
}

[notgull]

Interesting! I'd accept an MR moving to this, as long as said MR demonstrates that this algorithm is suitably random.

[taiki-e]

According to lemire/testingRNG#28 (comment) and document linked by it, does this seem to slightly reduce the quality?