Optimised code not building on suse 12.1 / gcc 4.6.2

[osae]

The same goes for other modules using cmake/Modules/UseOnlyNeeded.cmake
and simply leaving this out circumvents the problem.

Seems to be related to the following issue

// gcc -flto -Wl,--as-needed math.c -lm -o math
// removing either -flto or --as-needed makes it work
// also, if the argument is known at compile time the call disappears so it works

include <math.h>

int main(int argc, char **argv)
{
sqrt(argc);
}

[rolk]

Thank you for the bugreport!

I discussed this with Ove at the symposium, and I think the issue here is that the test in cmake/Modules/FindSuiteSparse.cmake (around line 215) isn't quite robust enough. It seems to only affect users on OpenSuSE, and we think it has something to do with the packaging of libraries on this platform. (It certainly works on Ubuntu).

We'll get it fixed, but it may take a while to setup the testing. In the meantime you can use the work-around Ove mentions here (commenting out include (UseOnlyNeeded) on line 112 or thereabout in CMakeLists.txt)

[bska]

Is there any progress on this issue?

[rolk]

Current state of this issue is: The problem is not reproducable on OpenSuSE 12.3; I am working on a test setup for OpenSuSE 12.1.

[bska]

Thanks a lot for the update!

[rolk]

I cannot reproduce this error on a minimal OpenSuSE 12.1 system because... compilation of opm-core aborts with an internal compiler error! (zypper info gcc says that I have version 4.6-15.1.3)

However, based on the test program you (@osae) provided, I have created a patch in the 256_linkplug branch of rolk/opmcore. Apply this (in opm-porsol) with:

wget -O - http://github.com/rolk/opm-core/commit/cdf8bf516f433c2a48fabedd33605577de96b267.patch | git am -

and see if this solves the problem. (It should report Performing Test HAVE_LINKER_PLUGIN_WITH_ASNEEDED - Failed somewhere near the end of the configure phase)

[rolk]

Sorry for the screw-up (forgot to refresh the browser window); the correct URL to test the fix should be:

wget -O - http://github.com/rolk/opm-core/commit/e2a18931990baf1e431ac946b3f4628940b34f6f.patch | git am -

[bska]

I'll close this as no longer pertinent since the LTO-by-default setting was reversed in OPM/opm-core@bfeac75.