https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63561
Bug ID: 63561 Summary: gfortran runtime hang on function print-stmt Product: gcc Version: 4.9.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libgomp Assignee: unassigned at gcc dot gnu.org Reporter: sidio47 at hotmail dot com CC: jakub at gcc dot gnu.org Created attachment 33735 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33735&action=edit Source code demonstrating runtime hang. Attached is a Fortran program that attempts to print the output of a function from a module. From my tests, when certain compile libraries are used, the program will wait indefinitely using all versions of GCC (gfortran) that I have access to (4.9.1, 4.8.3, 4.7.1) on three different systems: 1.) Linux 3.16.3-200.fc20.x86_64 #1 SMP Wed Sep 17 22:34:21 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux 2.) Linux 2.6.32-431.17.1.el6.x86_64 #1 SMP Wed May 7 23:32:49 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux 3.) Linux 2.6.32-358.23.2.el6.x86_64 #1 SMP Wed Oct 16 18:37:12 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux The code has no openmp or mpi calls. I believe the module to be irrelevant; i.e. the hang still occurs with an external function. 1.) Plain old vanilla gfortran works as intended. 2.) Adding the -fopenmp flag will cause it to hang. 3.) Adding the mpif90 wrapper from MVAPICH2 will cause it to hang. i.e: 1.) gfortran silly.F90 -o silly && ./silly <--- Works 2.) gfortran silly.F90 -o silly -fopenmp && ./silly <--- Hangs 3.) mpif90 silly.F90 -o silly && ./silly <--- Hangs