CPUTYPEs includig avx are suspicious with clang in stable/10

[John Baldwin]

On Friday, December 19, 2014 11:06:32 am Harry Schmalzbauer wrote:
>  I'm seeing sporadic problems (core dumps) with binaries compiled with
> CPUTYPE=core-i-avx.
> They run fine on IvyBridge, but fail on Haswells.
> Stripping avx from MACHINE_CPU (by defining CPUTYPE=corei7 instead of
> core-i-avx) solved all crashes on the haswell system.
> 
> I have no idea if applications like pkg(8) make use of AVX, I'd bet they
> don't do. So I guess it's something wrong with clang.
> Unfortuantely I currently don't have a development installation on any
> haswell system to provide some useful backtraces, but perhaps somebody
> with compiler knowledge can have a look at this problem?

If you are getting SIGILL (signal 4), all you really need is to get a core 
(even from a non-debug binary), then use gdb on the core and run 'x/i $rip' at 
the gdb prompt to see the instruction that triggered the fault.

-- 
John Baldwin