https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91512
--- Comment #18 from Sunil Pandey <skpgkp2 at gmail dot com> ---
(In reply to Thomas Koenig from comment #17)
> Simply passing on a huge number of arguments is not enough to trigger this.
>
> Here's a perl script to generate test cases:
>
> while ($n=shift)
> {
> open FOO, ">foo-$n.f90";
>
> print FOO <<EOF;
> module foo
> implicit none
> contains
> EOF
>
> print FOO "subroutine foo_proc";
> for ($i=0; $i<$n; $i++)
> {
> push (@var, "a" . sprintf("%3.3d", $i));
> }
>
> @call = ();
> push (@call, "(");
>
> for ($i=0; $i<$n-1; $i++)
> {
> push (@call, "&\n ") if ($i%10 == 0);
> push (@call, $var[$i] . ", ");
> }
> push (@call, $var[$n-1],")\n");
> print FOO @call;
>
> for ($i=0; $i<$n; $i++)
> {
> print FOO " real, dimension(:,:) :: $var[$i]\n";
> }
>
> print FOO " call bar";
> print FOO @call;
> print FOO " end subroutine\n";
> print FOO "end module\n";
> }
>
> Running this script with
>
> for a in 50 100 200 500 1000; do perl gener.pl $a; echo -n "$a ";
> /usr/bin/time -f "%e %M" gfortran -c -O2 foo-$a.f90; done
>
> gave me
>
> 50 3.21 272668
> 100 8.44 581860
> 200 20.15 1046780
> 500 52.32 1208684
> 1000 167.43 3493456
>
> so the CPU time does not come close to what is reported here.
> Memory use is quite high, though.
>
> What is the memory footprint of the compilation? Is your machine possibly
> starting to swap?
My system has plenty of memory. I don't think it's swapping issue. Here is
memory profile for before and after commit.
Before commit:
==============
$ /usr/bin/time -f "%e %M"
/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 -O3 -march=skylake -funroll-loops
-fconvert=big-endian module_first_rk_step_part1.fppized.f90
41.88 214612
$ /usr/bin/time -f "%e %M"
/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 -O3 -march=skylake
-fconvert=big-endian module_first_rk_step_part1.fppized.f90
40.88 214716
$ /usr/bin/time -f "%e %M"
/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
-fconvert=big-endian module_first_rk_step_part1.fppized.f90
40.38 214652
After commit:
=============
$ /usr/bin/time -f "%e %M"
/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 -O3 -march=skylake -funroll-loops
-fconvert=big-endian module_first_rk_step_part1.fppized.f90
1548.42 10111860
$ /usr/bin/time -f "%e %M"
/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 -O3 -march=skylake
-fconvert=big-endian module_first_rk_step_part1.fppized.f90
1088.74 2924072
$ /usr/bin/time -f "%e %M"
/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
-fconvert=big-endian module_first_rk_step_part1.fppized.f90
544.56 3129568
