https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81416
Bug ID: 81416 Summary: OpenMP craches if large arrays passed Product: gcc Version: 5.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: bz0815 at tirol dot com Target Milestone: --- gfortran crashes if OpenMP is activated and large arrays are passed: $ cat mod.f08 MODULE Mod USE OMP_LIB IMPLICIT NONE CONTAINS SUBROUTINE Print_Info(b) DOUBLE PRECISION,DIMENSION(:),INTENT(out) :: b b = 0.0 !$OMP PARALLEL PRINT *,'Hello' PRINT *,omp_get_num_threads() !$OMP END PARALLEL END SUBROUTINE Print_Info END MODULE Mod $ cat prog.f08 PROGRAM Prog USE Mod USE OMP_LIB IMPLICIT NONE INTEGER :: nthreads INTEGER,PARAMETER :: n = 131072 ! INTEGER,PARAMETER :: n = 262144 DOUBLE PRECISION,DIMENSION(n) :: b nthreads = 4 CALL OMP_SET_NUM_THREADS(nthreads) PRINT *,omp_get_num_procs() PRINT *,omp_get_max_threads() PRINT *,omp_get_num_threads() CALL Print_Info(b) END PROGRAM Prog If n is 131072 the program compiles and shows the expeced result: gfortran -Wall -O2 -std=f2008 -fcheck=all -fopenmp -c mod.f08 -o mod.o gfortran -Wall -O2 -std=f2008 -fcheck=all -fopenmp -o prog mod.o prog.f08 -lgomp $ ./prog 8 4 1 Hello 4 Hello 4 Hello 4 Hello 4 If n is 262144 the program compiles but craches: $ ./prog Segmentation fault (core dumped) The program runs if OpenMP is removed: gfortran -Wall -O2 -std=f2008 -fcheck=all -c mod.f08 -o mod.o gfortran -Wall -O2 -std=f2008 -fcheck=all -o prog mod.o prog.f08 -lgomp Wolfgang@DESKTOP ~/projects/test/openmp $ ./prog 8 4 1 Hello 1 The system used is: $ uname -a CYGWIN_NT-10.0 DESKTOP 2.8.1(0.312/5/3) 2017-07-03 14:11 x86_64 Cygwin The compiler used is: $ gfortran --version GNU Fortran (GCC) 5.4.0 Copyright (C) 2015 Free Software Foundation, Inc. GNU Fortran comes with NO WARRANTY, to the extent permitted by law. You may redistribute copies of GNU Fortran under the terms of the GNU General Public License. For more information about these matters, see the file named COPYING I experienced the same behavior also on other systems and other compler versions.