But is the result stable ? I remember bulding it with some patches a year or two ago, and while it compile fine, it crashed horribly when booting.

Not with any released version of clang, but yes, it works with snapshots of git master...

Again, false! This is highly dependent on:

1. What arch are you targeting.

2. What version of Linux are you trying to build? Mainline, stable, next?

3. What configs are you trying.

4. What version of clang are you using.

For example, pixel 2 kernel is arm64, 4.4 stable kernel, limited configs, and clang-4.

Things for the most part are pretty green with released versions of clang. There are some long tail configs or combos of the above, but it's pretty minimal and we have a good handle on them.

I'm mainly working off our experience in OpenMandriva, so at least for your standard general-purpose Linux distribution, it doesn't work yet.