On Fri, May 22, 2015 at 12:38 PM, Ian Hinder <ian.hinder@aei.mpg.de> wrote:

On 22 May 2015, at 18:34, Ian Hinder <ian.hinder@aei.mpg.de> wrote:


On 22 May 2015, at 16:10, Roberto De Pietri <roberto.depietri@unipr.it> wrote:

Hi Ian:


Thanks for the answer. I followed exactly your procedure and I was very surprised of having
a failing compilation. Than I starting tracing back the problem.
* All the thorns except one were compiling correctly.
* The failing thorn was CarpetIOHDF5 and of the 5 source files present only 3 failed
* The error was very strange because the only real problem was related to
 a system include “/opt/local/lib/gcc49/gcc/x86_64-apple-darwin14/4.9.2/include/mmintrin.h”
 and was related to conversion using AVX intel intrinsic. The error were of the type:

 error: can’t convert between vector values of different size
    return (__m64) __builtin_ia32_vec_init_v2si (__i, 0);

There is a stackoverflow post (http://stackoverflow.com/questions/19043109/gcc-4-8-1-combining-c-code-with-c11-code ) which describes a similar problem, which I haven't studied in depth, but they seem to suggest that it's a bug in gcc, and that setting --std=gnu++11 instead of --std=c++11 in CXXFLAGS will work around the problem.
Yes, it seems that this describes the problem we're having. GCC uses __attribute__ to provide certain language extensions, e.g. for vectorization. These are not optional declarations -- these modify function definition and can't just be omitted.

And HDF5 does just that: it #defines __attribute__ to be empty (file H5api_adpt.h, near the beginning) if the file is included from C++. I have no idea why they would think this is legal, or why they would think this is even a good idea. We use __attribute__ in Cactus (after checking via autoconf whether it is supported) for a variety of optimizations and security checks.

I would try adding the line

#undef __attribute__

right after (below) any line that says

#include <hdf5.h>

to undo (part of) the damage that HDF5 does. We should also complain to the HDF5 authors.

-erik
 
 We currently have

CXXFLAGS = -g -std=c++14

so I'm guessing that changing this to

CXXFLAGS = -g -std=gnu++14

might have the same effect.

What I don't understand is why we didn't pick this up in testing.  I successfully compiled the whole ET using exactly that set of MacPorts packages and the optionlist before the release, and the gcc49 macports package hasn't been updated since 4 weeks ago.

I should add that I tested it on 10.9.5, since I haven't been brave enough to update to 10.10 yet.  I think Erik was testing on 10.10, but he can confirm that.



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Erik Schnetter <schnetter@cct.lsu.edu>
http://www.perimeterinstitute.ca/personal/eschnetter/