pub unsafe fn _mm_mask_alignr_epi64(
    src: __m128i, 
    k: __mmask8, 
    a: __m128i, 
    b: __m128i, 
    const IMM8: i32
) -> __m128iAvailable on x86 and target feature 
avx512f,avx512vl only.Expand description
Concatenate a and b into a 32-byte immediate result, shift the result right by imm8 64-bit elements, and store the low 16 bytes (2 elements) in dst using writemask k (elements are copied from src when the corresponding mask bit is not set).