CPUTYPEs includig avx are suspicious with clang in stable/10

[Dimitry Andric]

On 19 Dec 2014, at 17:06, Harry Schmalzbauer <freebsd at omnilan.de> 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.

Can you provide a concrete test case?  E.g. binaries with both
optimizations, of which one exhibits the crash?



> I have no idea if applications like pkg(8) make use of AVX, I'd bet they
> don't do.

If you put CPUTYPE?=core-i-avx in /etc/make.conf, and recompile ports
with that configuration, they can certainly use AVX, if there are parts
in the code that can be vectorized (e.g. certain loops).


> 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?

It is hard to say anything without more concrete information. :)

-Dimitry

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