While LLVM 6.0 is available as the latest and greatest stable Mesa release, LLVM 5.0.2 is in the works for releasing in the days ahead. Besides normal bug fixes, LLVM 5.0.2 also carries the compiler-side Retpoline patches for Spectre…

Source: Phoronix – LLVM 5.0.2-RC1 Released With Spectre Patches