endian issue of llvm-gcc and llvm backend

Hello, Sam

I used non-arm backend, and I used a target which likes mips has both big and little endianness. And I have ported llvm-gcc to this platform along with llvm backend.
The issue is about IR endianness and how backend deal with the data and instructions in different endian, since I discovered 2 different IR generates the same asm code by llc for different endian target.