https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91646
Bug ID: 91646 Summary: gfortran takes long time and consumes a lot of memory Product: gcc Version: 9.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: luomo1138 at yahoo dot com Target Milestone: --- Created attachment 46806 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46806&action=edit source file demonstrating issue Hello, I have an issue with gfortran taking a very long time and consuming a lot of memory to compile a file. The attached file compiles in about one second when using either gfortran 4.9.2 or the Intel Fortran compiler (ifort). However, when I use gfortran 9.1.0, that file takes a very long time to compile. When I compile the file with this command: ``` gfortran -Wall -c -pass-exit-codes -ffree-line-length-0 -g LVT_statsDataMod.F90 ``` it takes 10 minutes to compile and uses approximately 20GB of memory. Similarly for "-O0". When I use either "-O1" or "-O2", it takes over an hour to compile and uses at least 35GB of memory. (I do not know exactly how long because I killed it after one hour.) I have seen similar behaviour with gfortran 7.3 and 8.1 as well. I also compiled with "-Wextra" and "-fno-strict-aliasing -fwrapv -fno-aggressive-loop-optimizations", but nothing was reported. Do you have any suggestions? * Exact version, system type, and GCC build options: ``` $ gfortran -v Using built-in specs. COLLECT_GCC=gfortran COLLECT_LTO_WRAPPER=/gpfsm/dulocal/sles11/other/SLES11.3/gcc/9.1/libexec/gcc/x86_64-pc-linux-gnu/9.1.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: /gpfsm/dnbsrc/other/GCC/SLES11/9.1/gcc-9.1.0/configure --prefix=/gpfsm/dulocal/sles11/other/SLES11.3/gcc/9.1 --enable-languages=all --enable-bootstrap Thread model: posix gcc version 9.1.0 (GCC) ``` * complete command line: ``` gfortran -Wall -c -pass-exit-codes -ffree-line-length-0 -g LVT_statsDataMod.F90 ``` * compiler output: None * preprocessed file: Attached file does not require any preprocessing. Here is the version of gfortran that performs as I expect: ``` $ gfortran -v Using built-in specs. COLLECT_GCC=gfortran COLLECT_LTO_WRAPPER=/gpfsm/dulocal/sles11/other/SLES11.3/gcc/4.9.2/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.9.2/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: /gpfsm/dnbsrc/other/GCC/SLES11/4.9.2/gcc-4.9.2/configure --prefix=/usr/local/other/SLES11.3/gcc/4.9.2 --enable-languages=all --enable-bootstrap Thread model: posix gcc version 4.9.2 (GCC) ``` Thanks, Jim