The following issue has been SUBMITTED. ====================================================================== http://public.kitware.com/Bug/view.php?id=14567 ====================================================================== Reported By: Daniel Landau Assigned To: ====================================================================== Project: CMake Issue ID: 14567 Category: Modules Reproducibility: always Severity: tweak Priority: low Status: new ====================================================================== Date Submitted: 2013-11-13 12:48 EST Last Modified: 2013-11-13 12:48 EST ====================================================================== Summary: FindOpenMP is incorrect for compilers that accept OpenMP with no flags Description: The CMake FindOpenMP.cmake module tries several flags in order to find out which one is supported by the compiler. The way it does it is seems to be by testing whether a compilation returns a successful exit status. The overall effect is that since "-openmp" is tested for before " ", the former gets chosen as the flag for OpenMP when the compiler doesn't require any.
The practical problem here is that the compiler that accepts "-openmp" without intending for it to signify OpenMP interpretes that as "-o penmp". This is not as big a problem as it first sounds, because CMake usually includes another -o flag later in the command line. In fact, I couldn't produce a small test case where this would lead to problems. It does lead to problems in the real word case of molecular dynamics software Gromacs (http://www.gromacs.org/), where some linking steps get generated with the order of first the intended -o flag and later -openmp. A simple fix is to simply swap the order of testing for no flag (" ") and "-openmp". Steps to Reproduce: Any simple CMakeLists.txt with OpenMP and a compiler that accepts OpenMP without flags (I used the Cray compiler) will produce compilation commands with -openmp, but I couldn't generate a small test case where that leads to explicit problems. ====================================================================== Issue History Date Modified Username Field Change ====================================================================== 2013-11-13 12:48 Daniel Landau New Issue ====================================================================== -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://public.kitware.com/cgi-bin/mailman/listinfo/cmake-developers
