https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101241
--- Comment #8 from Raymond Langer <r.langer at itv dot rwth-aachen.de> --- I didn't configure gcc myself. I run gcc in a Clean Linux docker container: docker run -it clearlinux /bin/bash In the docker container, I run: swupd bundle-add c-basic gcc --version gcc (Clear Linux OS for Intel Architecture) 11.1.1 20210617 releases/gcc-11.1.0-303-ge86ad5ad01 Copyright (C) 2021 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. The uploaded file does not compile with: g++ -c a-eigen_bug.ii -Ofast