Function _mm256_dp_ps 

pub fn _mm256_dp_ps(a: __m256, b: __m256, const IMM8: i32) -> __m256

Available on x86-64 and target feature avx only.

Conditionally multiplies the packed single-precision (32-bit) floating-point elements in a and b using the high 4 bits in imm8, sum the four products, and conditionally return the sum using the low 4 bits of imm8.

Intel’s documentation