https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81350
Bug ID: 81350 Summary: gfortran OpenMP taskloop segfaults or incorrect Product: gcc Version: 7.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: jeff.science at gmail dot com Target Milestone: --- Created attachment 41697 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41697&action=edit source code associated with bug Code is correct with Intel 18 but generates erroneous results or segfaults with GCC 7.1. jrhammon-mac01:FORTRAN jrhammon$ ifort -std08 -fpp -g -O3 -xHOST -DRADIUS=2 -DSTAR -qopenmp stencil-taskloop-openmp.f90 -o stencil-taskloop-openmp-ifort jrhammon-mac01:FORTRAN jrhammon$ gfortran-7 -std=f2008 -cpp -g -O3 -mtune=native -DRADIUS=2 -DSTAR -fopenmp stencil-taskloop-openmp.f90 -o stencil-taskloop-openmp-gfortran jrhammon-mac01:FORTRAN jrhammon$ ./stencil-taskloop-openmp-ifort 10 1000 Parallel Research Kernels Fortran OpenMP TASKLOOP Stencil execution on 2D grid Number of threads = 4 Grid size = 1000 Radius of stencil = 2 Type of stencil = star Data type = double precision Compact representation of stencil loop body Untiled Number of iterations = 10 Solution validates Rate (MFlops/s): 7787.263159 Avg time (s): 0.002420 jrhammon-mac01:FORTRAN jrhammon$ ./stencil-taskloop-openmp-gfortran 10 1000 Parallel Research Kernels Fortran OpenMP TASKLOOP Stencil execution on 2D grid Number of threads = 4 Grid size = 1000 Radius of stencil = 2 Type of stencil = star Data type = double precision Compact representation of stencil loop body Untiled Number of iterations = 10 Segmentation fault: 11 jrhammon-mac01:FORTRAN jrhammon$ ./stencil-taskloop-openmp-ifort 10 100 Parallel Research Kernels Fortran OpenMP TASKLOOP Stencil execution on 2D grid Number of threads = 4 Grid size = 100 Radius of stencil = 2 Type of stencil = star Data type = double precision Compact representation of stencil loop body Untiled Number of iterations = 10 Solution validates Rate (MFlops/s): 411.036158 Avg time (s): 0.000426 jrhammon-mac01:FORTRAN jrhammon$ ./stencil-taskloop-openmp-gfortran 10 100 Parallel Research Kernels Fortran OpenMP TASKLOOP Stencil execution on 2D grid Number of threads = 4 Grid size = 100 Radius of stencil = 2 Type of stencil = star Data type = double precision Compact representation of stencil loop body Untiled Number of iterations = 10 ERROR: L1 norm = 0.000000 Reference L1 norm = 22.000000 Rate (MFlops/s): 814.866756 Avg time (s): 0.000215 $ gfortran-7 -v Using built-in specs. COLLECT_GCC=gfortran-7 COLLECT_LTO_WRAPPER=/usr/local/Cellar/gcc/7.1.0/libexec/gcc/x86_64-apple-darwin16.6.0/7.1.0/lto-wrapper Target: x86_64-apple-darwin16.6.0 Configured with: ../configure --build=x86_64-apple-darwin16.6.0 --prefix=/usr/local/Cellar/gcc/7.1.0 --libdir=/usr/local/Cellar/gcc/7.1.0/lib/gcc/7 --enable-languages=c,c++,objc,obj-c++,fortran --program-suffix=-7 --with-gmp=/usr/local/opt/gmp --with-mpfr=/usr/local/opt/mpfr --with-mpc=/usr/local/opt/libmpc --with-isl=/usr/local/opt/isl --with-system-zlib --enable-checking=release --with-pkgversion='Homebrew GCC 7.1.0' --with-bugurl=https://github.com/Homebrew/homebrew-core/issues --disable-nls --with-native-system-header-dir=/usr/include --with-sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.12.sdk Thread model: posix gcc version 7.1.0 (Homebrew GCC 7.1.0)