It's 2020 And GCC Has Finally Converted From SVN To Git
On Saturday, the transition of GCC's repository to Git was completed using Eric S Raymond's Reposurgeon utility.
Git conversion ... complete. Verification in progress. #GCC pic.twitter.com/bm6GaUYsTA
— GCC - GNU Toolchain (@gnutools) January 11, 2020
Though they quite aren't back open for business yet but still going through verifications. The hope is to have the tree open again on Monday should all verifications pass and nothing too major come up. At the moment it does look like there may be one issue with slow performance for trivially commits but no further word on that yet.
So moving forward they'll be using a Git workflow for developing GCC, similar to LLVM's transition from SVN to Git that finally wrapped up a few months ago.