(1) Added code to generate loops for replication of a node

Next step is to add support for new bind intrinsic.
(2) Minor bug fixes
M    llvm/include/llvm/IR/DFGraph.h
M    llvm/lib/Transforms/BuildDFG/BuildDFG.cpp
M    llvm/lib/Transforms/DFG2LLVM_X86/DFG2LLVM_X86.cpp