Porting to clang/llvm sounds like it was a good idea. How many C toolchains can now produce a working Linux? I think tcc could compile some Linux kernels? I

Porting to clang/llvm sounds like it was a good idea. How many C toolchains can now produce a working Linux? I think tcc could compile some Linux kernels? I imagine intel, Microsoft, and IBM closed-source C compilers might be able to do so as well?