Add _mm_loadu_si64 (#870)
Add _mm_loadu_si64 (#870)

Co-authored-by: Amanieu d'Antras <92db609b8007e8ad5e633f1530d9df21d90665f4@gmail.com>
rust-lang/stdarch,rust-lang/stdarch,rust-lang/stdarch,rust-lang/stdarch,rust-lang/stdarch