http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59811
Bug ID: 59811 Summary: Huge increase in memory usage and compile time with gfortran 4.8 Product: gcc Version: 4.8.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: bastian.feigl at kit dot edu Created attachment 31833 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31833&action=edit Example fortran source code file with problems with gfortran 4.8 When switching from gfortran 4.7 to gfortran 4.8 the memory usage and compile time vastly increases for some files in our project, e.g. for the attached example file. gfortran 4.8.2 needs 50s to compile, using up to 1.7 GB of RAM, while gfortran 4.7 compiles it in 7s with a memory usage of 136 MB. The command line of the gfortran-call for the attached example is /opt/gcc/4.8.2/bin/gfortran -fno-automatic -ffixed-line-length-none -O2 -c FermionBoxEventempCoupling_Div.F -o output.o The problem seems to be partly linked to the option -fno-automatic, since omitting it inhibits the memory increase, but the compile time is still 14s with gfortran 4.8, compared to 6s with gfortran 4.7. The problem arises with optimizations -O2 and -O1 lead to a similar discrepancy, with -O0 the problem does not exist. The gfortran 4.8 which shows the problematic behaviour is built with: Target: x86_64-unknown-linux-gnu Configured with: ../gcc-4.8.2/configure --prefix=/opt/gcc/4.8.2 --enable-languages=c,c++,fortran gcc version 4.8.2 (GCC) The gfortran 4.7 is the built-in from openSUSE 12.2: Target: x86_64-suse-linux Configured with: ../configure --prefix=/usr --infodir=/usr/share/info --mandir=/usr/share/man --libdir=/usr/lib64 --libexecdir=/usr/lib64 --enable-languages=c,c++,objc,fortran,obj-c++,java,ada --enable-checking=release --with-gxx-include-dir=/usr/include/c++/4.7 --enable-ssp --disable-libssp --disable-libitm --disable-plugin --with-bugurl=http://bugs.opensuse.org/ --with-pkgversion='SUSE Linux' --disable-libgcj --disable-libmudflap --with-slibdir=/lib64 --with-system-zlib --enable-__cxa_atexit --enable-libstdcxx-allocator=new --disable-libstdcxx-pch --enable-version-specific-runtime-libs --enable-linker-build-id --program-suffix=-4.7 --enable-linux-futex --without-system-libunwind --with-arch-32=i586 --with-tune=generic --build=x86_64-suse-linux gcc version 4.7.1 20120723 [gcc-4_7-branch revision 189773] (SUSE Linux)