Alright, making it more non-compliant, then. Still creates problems for everyone and also necessitates a larger jump in the GCC version to support (unless you're going to back port the new extensions to every version that the kernel currently works with). Currently you can compile the Linux kernel with GCC 5.1. If you changed the compiler to support this one feature (or any other) you'd either need to back port it several versions (potentially back to 5) or abandon all of them. Which is probably a no-go with a project that's overall as conservative as the Linux kernel project.