Function core::arch::x86::_mm_cvtepi8_epi64

pub unsafe fn _mm_cvtepi8_epi64(a: __m128i) -> __m128i

This is supported on (non-crate feature miri-test-libstd or test or doctest) and x86 and target feature sse4.1 only.

Sign extend packed 8-bit integers in the low 8 bytes of a to packed 64-bit integers

Intel’s documentation