No, the point was for today's compilers they could have something that compiles quickly and does everything they want.
Elaborate? Why?
I am saying they could have either implemented this in the past (and thus had it land by now) or implement it now (and have it land in e.g. GCC in the near future). Neither appears to be the case. I was not suggesting they have a time machine. I can't understand what you're finding so difficult about this.
This really isn't rocket science. They need something that works in the kernel on today's compilers. The end.
I have no idea how you make this stuff up, but Linux and GCC have thousands of developers working on them from all across the world, and Linux heavily takes advantage of GCC built-ins. There even exist active maintainers who understand and contribute to both... not that that is in any shape or form a requirement for putting out a request from one project to the other. The idea that they would've been unable to find a single person with sufficient interest & understanding of compilers to implement min/max in it is downright absurd. If they wanted to do this someone would have implemented it a long time ago. And yes, the end.
If a new compiler extension was proposed and implemented and released in both llvm and gcc, some years after that they could drop support. But there would be no real imperative to drop support early since they will already have developed some code that works okay on those toolchains.