Function pmaddwd 

fn pmaddwd<'tcx>(
    ecx: &mut MiriInterpCx<'tcx>,
    left: &OpTy<'tcx>,
    right: &OpTy<'tcx>,
    dest: &MPlaceTy<'tcx>,
) -> InterpResult<'tcx, ()>

Multiply packed signed 16-bit integers in left and right, producing intermediate signed 32-bit integers. Horizontally add adjacent pairs of intermediate 32-bit integers, and pack the results in dest.

https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm_madd_epi16 https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm256_madd_epi16 https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm512_madd_epi16