AMD should concentrate on making LLVM and GCC work great on AMD processors, by contributing the needed code. They are already making some contributions but could be doing more, and they could be funding experts to work on that and giving those experts the information they need.
It says they might as well stop dividing their effort and focus on the upstream LLVM (or alternatively treat their own version as just a development branch that they can push upstream from). While they have expertise on the details of their processor they may benefit more by cooperating with all the compiler experts outside their company.
To fix this problem AMD would have to work on making LLVM and GCC work great on Intel processors. That would be the only way to make people not use the Intel compiler for extra performance and ending up with binaries that are crippled for AMD. Clearly that's not a solution for this problem.
