Further refactoring of CodeGen_LLVM's Div visitor.
Further refactoring of CodeGen_LLVM's Div visitor.

kgnk/Halide,kgnk/Halide,ronen/Halide,tdenniston/Halide,psuriana/Halide,jiawen/Halide,tdenniston/Halide,ronen/Halide,psuriana/Halide,psuriana/Halide,psuriana/Halide,ronen/Halide,kgnk/Halide,jiawen/Halide,tdenniston/Halide,jiawen/Halide,jiawen/Halide,kgnk/Halide,tdenniston/Halide,psuriana/Halide,kgnk/Halide,jiawen/Halide,tdenniston/Halide,kgnk/Halide,tdenniston/Halide,psuriana/Halide,psuriana/Halide,ronen/Halide,ronen/Halide,jiawen/Halide,ronen/Halide,kgnk/Halide,kgnk/Halide,ronen/Halide,ronen/Halide,tdenniston/Halide,tdenniston/Halide,jiawen/Halide