https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91512
--- Comment #15 from rguenther at suse dot de <rguenther at suse dot de> --- On Thu, 22 Aug 2019, skpgkp2 at gmail dot com wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91512 > > --- Comment #14 from Sunil Pandey <skpgkp2 at gmail dot com> --- > (In reply to Richard Biener from comment #7) > > (In reply to Sunil Pandey from comment #4) > > > Actually it is spec cpu 2017 521.wrf benchmark getting this problem while > > > compiling. Compilation taking forever, you can see while compiling file > > > module_first_rk_step_part1.fppized.f90 as a representative. > > > > Note this file contains a single function which (besides USEing quite a > > number > > of modules...) has only function calls involving a lot of parameters > > effectively forwarding parameters from the function. Thus > > > > SUBROUTINE foo (psim, ..., ims, ime, jms, jme) > > REAL ,DIMENSION(ims:ime,jms:jme), INTENT(INOUT) :: psim > > call sub1 (PSIM=psim, ...) > > call sub2 (PSIM=psim, ...) > > END SUBROUTINE > > > > with a _lot_ of arrays being passed through. A simple testcase like > > > > SUBROUTINE sub1 (psim, ims, ime, jms, jme) > > REAL ,DIMENSION(ims:ime,jms:jme), INTENT(INOUT) :: psim > > END SUBROUTINE > > SUBROUTINE foo (psim, ims, ime, jms, jme) > > REAL ,DIMENSION(ims:ime,jms:jme), INTENT(INOUT) :: psim > > call sub1 (psim, ims, ime, jms, jme) > > END SUBROUTINE > > > > doesn't show any extra loops generated though, so I'm not sure what to > > look after. > > It seems very hard to create a small test case which reproduce the long > compile > time problem. Unfortunately, I'm not allowed to upload spec source file. Also > it's very big with lots of module dependency. Assuming you have spec 2017 > sources, > > Here is unmodified command line, which show compile time problem. > > Spec build dir: > =============== > > /local/skpandey/gccwork/specx5/cpu2017/benchspec/CPU/521.wrf_r/build/build_base_gcc-10.0.0-x86-64.0000 > > Before the commit in question: > ============================== > > Take 41 second to compile unmodified file with -O2 -march=skylake > > $ time > /local/skpandey/gccwork/gcc_trunk/tools-build/gcc-debug/release.a4ba5c3ec624008e899a8bcb687359db25140c23/usr/gcc-10.0.0-x86-64/bin/gfortran > -m64 -c -o module_first_rk_step_part1.fppized.o -I. -I./netcdf/include > -I./inc > -fno-unsafe-math-optimizations -mfpmath=sse -O2 -march=skylake -funroll-loops > -fconvert=big-endian module_first_rk_step_part1.fppized.f90 > > real 0m41.295s > user 0m41.031s > sys 0m0.204s > > After the commit in question: > ============================= > > It take about 12 minute with -O2 -march=skylake > > $ time > /local/skpandey/gccwork/gcc_trunk/tools-build/gcc-debug/release/usr/gcc-10.0.0-x86-64/bin/gfortran > -m64 -c -o module_first_rk_step_part1.fppized.o -I. -I./netcdf/include > -I./inc > -fno-unsafe-math-optimizations -mfpmath=sse -O2 -march=skylake -funroll-loops > -fconvert=big-endian module_first_rk_step_part1.fppized.f90 > > real 11m59.498s > user 11m53.304s > sys 0m4.835s > > > With higher optimization like -O3 or -Ofast, it take even longer and I have to > kill it. Does it help to omit -funroll-loops?
