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## _mm512_castpd128_pd512

# Function _mm512_castpd128_pd512

1.89.0 (const: unstable) · Source

    pub fn _mm512_castpd128_pd512(a: __m128d) -> __m512d

Available on x86-64 and target feature `avx512f` and (x86 or x86-64) only.
Expand description

Cast vector of type __m128d to type __m512d; the upper 384 bits of the result are indeterminate.

In the Intel documentation, the upper bits are declared to be “undefined”. This is not equivalent to `mem::MaybeUninit`; instead, these bits are non-deterministically set to some valid value. In practice, this is typically equivalent to `mem::zeroed`.

This intrinsic is only used for compilation and does not generate any instructions, thus it has zero latency.

Intel’s documentation