With the recent release of LLVM 9.0 the RISC-V back-end was promoted from an experimental CPU back-end to being made “official” for this royalty-free CPU ISA. Work though isn’t over on the LLVM RISC-V support with new features continuing to land, like link-time optimizations (LTO) most recently being enabled within the Clang 10 code.
article: https://www.phoronix.com/scan.php?page=news_item&px=RISC-V-LLVM-Clang-LTO