This has been in progress for a while now. XL 16.1 integrated in the Clang front-end (as xlclang/xlclang++) and was available to play with around the beginning

This has been in progress for a while now. XL 16.1 integrated in the Clang front-end (as xlclang/xlclang++) and was available to play with around the beginning of 2019. In early 2019 IBM had already started working on building out the support for writing XCOFF binaries in LLVM as ground work to move the back-end over. I got the front-end working on AIX in ~2016 so that libclang could be used for tooling, but the upstream patch lingered until IBM picked up the work in Feb 2019 and started really building it out. Tangentially, Oracle did something similar but instead adopted GCC’s front-end for their compiler. What’s unclear for both is how they will modify the compiler release cycles to accommodate the upstream LLVM (& GCC) release cycles so they don’t linger too long on old code. IIRC XL 16.1 xlclang was based around a snapshot of Clang 4.x , which is not great when we’re now on the eve of Clang 10.