Thanks Renato, Yes, i wanted to cross-compile from x86_64 to ARM. More specifically, I needed to do it for the cortex m0 processor.
My eventual goal would be to tweak a certain part of the instruction scheduler specific to the project I am working on. So I am thinking if it is possible using LLVM. I was going thru the documentation of LLVM-backend and thought as a first step, try to generate a cross compiler for ARM and then tweak the code once the cross compiler is ready. I saw that there is support for cortex-a9 onwards, but am not sure, if there is any support for cortex m series. In that case, I would have implement a backend which would support this particular board. This seems to be a long shot, but would you provide your opinion if this is possible at all? If not, then what would be the proper approach?