LLVM Begins Gaining Ground On Windows
Phoronix: LLVM Begins Gaining Ground On Windows
While the LLVM compiler infrastructure is supported to some extent on Microsoft Windows, the main focus of LLVM development has been -- and continues to be -- around Linux and OS X support. However, with a recent push, the LLVM toolchain is beginning to make more serious progress on Windows...
I think that LLVM on Windows was working for around one year, but not upstream. C++ Builder is using it for 64 bit version for an year for now