llvm 3.7 for rawhide and then f23

[Adam Jackson]

On Sun, 2015-09-20 at 21:00 +0800, Christopher Meng wrote:
> On 9/20/15, David Airlie <airlied at redhat.com> wrote:
> > It's llvm, there is never a good time to upgrade it and no llvm release is
> > backwards compatible.
> 
> Yes, so unless someone is pretty familiar with LLVM upstream, keep
> reading every changeset, no body can guarantee what will happen.

That's not really a fair assessment.  By far the most important thing
in Fedora that needs llvm is Mesa.  The llvm build system has a fairly
comprehensive test suite (which, btw, fails on at least arm with 3.6.1,
but passes on all arches with 3.7), and Mesa has another test suite in
the form of piglit that we can use to ensure that changing llvm doesn't
regress llvmpipe or r600 or radeonsi.

So we can in fact be pretty confident that llvm upgrades won't break
the things we actually use llvm for in Fedora.

- ajax