Contributions to the GNU Compiler Collection (GCC) require a copyright assignment to the Free Software Foundation for this GPLv3-licensed compiler. It turns out the University of California Berkeley lawyers are taking issue with this, temporarily holding up the compiler back-end from merging.
Palmer Dabbelt, a student of UC Berkeley who has been working on the "Hurricane" multi-core RISC-V implementation, wrote on a RISC-V mailing list: "Yes [of plans to merge the code to trunk], but right now it's blocked on UC Berkeley's lawyers who won't let us assign copyright to the FSF, which is required for upstreaming any of the toolchain. This is also super frustrating for me (and I assume everyone else involved), so you're not alone here."
With RISC-V being a promising open-source, royalty-free instruction set born at UC Berkeley and making a lot of progress, it's a pity to see the compiler support being held up by lawyers at this educational institution having issue with copyright assignment to FSF.