I think, this is an upstream bug -- and I reported it there:
But meanwhile something needs to be done about it -- the port was miscompiled here and crashing (from SIGILL) because it tried to use the SSE-instructions, which my CPU does not have.
My workaround was to run `make configure' and then edit the generated files to remove the bogus flag from CFLAGS. But I'm not sure, what other unasked-for values are added -- it may not be just the penryn...
Auto-assigned to maintainer kwm@FreeBSD.org
Do you have the SIMD option enabled by chance? If so can you try to disable that as a work around for now?
(In reply to Koop Mast from comment #2)
> Do you have the SIMD option enabled by chance? If so can you try to disable
> that as a work around for now?
Yes, indeed. Turning this option off fixes the problem. The description of the autofoo macro impementing the --with-gcc-arch feature says:
>> The main emphasis here is on recent CPUs, on the principle that doing high-performance computing on old hardware is uncommon.
I'd recommend removing the SIMD-option from the port entirely -- FreeBSD already allows one to specify the CPUTYPE (in /etc/make.conf) and that, at least, will come with no surprises...
A commit references this bug:
Date: Tue Dec 30 21:48:39 UTC 2014
New revision: 375859
Update ImageMagick to 6.9.0-2.
Disable SIMD option, the --with-gcc-arch only takes recent cpus into account.
And doesn't propperly check the host cpu for the flags. 
PR: 196188 
Submitted by: mi@ALDAN.algebra.com
Keeping this open as a reminder for myself that I would like a proper SIMD option..