Bug#974073: gcc-10: arm64 internal compiler error: canonical types differ for identical types

[Wookey <wookey@debian.org>]

Package: gcc-10
Followup-For: Bug #974073

I tried to build SparseMatrix-2.ii using the sample command on an Ampere emag (64GB RAM). It built successfully in an unstable chroot, taking about 5 minutes, consuming about 3.5GB resident memory to do so, confirming what you found.

However building polymake under sbuild still fails, just as in #974058.
So does building polymake in the above (unclean) chroot, or compiling
SparseMatrix.cc alone. Max RAM usage in the polymake build got to
about 20G using 16 cores, but fell back to about 4.7G and only 4 cores
when the sparseMatrix compile dies. 

Building the one file alone:
g++ -c -o /home/wookey/debian/polymake-4.1/build/Opt/apps/common/cpperl/SparseMatrix-2.o -MMD -MT /home/wookey/debian/polymake-4.1/build/Opt/apps/common/cpperl/SparseMatrix-2.o -MF /home/wookey/debian/polymake-4.1/build/Opt/apps/common/cpperl/SparseMatrix-2.o.d -fPIC -pipe -g -O2 -fdebug-prefix-map=/home/wookey/debian/polymake-4.1=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -std=c++14 -ftemplate-depth-200 -fno-strict-aliasing -fopenmp -Wshadow -Wlogical-op -Wconversion -Wzero-as-null-pointer-constant -Wno-parentheses -Wno-error=unused-function -Wno-stringop-overflow -Wno-array-bounds -DPOLYMAKE_WITH_FLINT  -DPOLYMAKE_DEBUG=0 -DNDEBUG -O2 -DPOLYMAKE_APPNAME=common -I/home/wookey/debian/polymake-4.1/include/app-wrappers -I/home/wookey/debian/polymake-4.1/include/apps -I/home/wookey/debian/polymake-4.1/include/external/permlib -I/home/wookey/debian/polymake-4.1/include/external/TOSimplex -I/home/wookey/debian/polymake-4.1/include/core-wrappers -I/home/wookey/debian/polymake-4.1/include/core /home/wookey/debian/polymake-4.1/apps/common/cpperl/generated/SparseMatrix-2.cc && : 'COMPILER_USED=10.2.0'

fails quickly with the same /home/wookey/debian/polymake-4.1/include/core/polymake/GenericVector.h:304:11: internal compiler error: canonical types differ for identical types error.
This only gets to about 500MB RAM usage before dying.

So, no this doesn't seem to be an OOM-killer issue. Not sure what _is_ going on with all that hardcore C++ typing. I'll ask internally if anyone has a clue.

--
Wookey