This adds new intrinsics "hadd_*" for horizontal or reduction sum operation to facilitate efficient code generation for "sum of absolute differences" operation.
The patch also contains the introduction of corresponding SDNodes and basic legalization support.Sanity of the generated code is tested on X86.
This is 2nd of the three patches.The 1st patch can be referred here, http://reviews.llvm.org/D10867
Nothing is being loaded here. You can just say that, "The argument is a vector of any integer or floating-point type."