Vector.slice is a method at the top-level class of the Vector API that concatenates the 2 inputs into an intermediate composite and extracts a window equal to the size of the inputs into the result. It is used in vector conversion methods where the part number is not 0 to slice the parts to the correct positions. Slicing is also used in text processing such as utf8 and utf16 validation. x86 starting from SSSE3 has palignr which does vector slicing very efficiently. As a result, I think it is beneficial to add a C2 node for this operation as well as intrinsify Vector.slice method.