Function core::arch::x86_64::_mm256_insertf128_ps

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

Available on (x86 or x86-64) and target feature avx and x86-64 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