[Bug c/106800] Expose more vector extensions in C

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106800

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 58699
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58699&action=edit
patches in progress

I've come up with this sofar, it's a bit difficult to navigate the current
behavior wrt. truthvalue conversion and I am not too happy with the required
"hacks".

A C FE expert might provide guidance.