Function _mm_clmulepi64_si128 

pub fn _mm_clmulepi64_si128(a: __m128i, b: __m128i, const IMM8: i32) -> __m128i

Available on x86-64 and target feature pclmulqdq only.

Performs a carry-less multiplication of two 64-bit polynomials over the finite field GF(2).

The immediate byte is used for determining which halves of a and b should be used. Immediate bits other than 0 and 4 are ignored.

Intel’s documentation