add some signed/unsigned arithmetic operation functions into APInt.h to
handle the signed/unsigned issue. These functions will be defined inside a
namespace "APIntOps" which is inside llvm namespace.
llvm-svn: 34053
It is a functional replacement for common case integer type like "unsigned",
"uint64_t", but also allows non-byte-width integer type and large integer
value types such as 3-bits, 15-bits, or more than 64-bits of precision. For
more details, see pr1043.
llvm-svn: 33951
