pub unsafe fn _mm512_castpd256_pd512(a: __m256d) -> __m512d
🔬 This is a nightly-only experimental API. (stdsimd #48556)
Available on x86 and target feature avx512f only.
Expand description

Cast vector of type __m256d to type __m512d; the upper 256 bits of the result are undefined. This intrinsic is only used for compilation and does not generate any instructions, thus it has zero latency.

Intel’s documentation