Function core::arch::x86::_mm256_insertf128_ps

pub unsafe fn _mm256_insertf128_ps<const IMM1: i32>(
    a: __m256, 
    b: __m128
) -> __m256

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

Copies a to result, then inserts 128 bits (composed of 4 packed single-precision (32-bit) floating-point elements) from b into result at the location specified by imm8.

Intel’s documentation