https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99460
--- Comment #2 from mexon <gcc.mexon at spamgourmet dot com> --- For completeness, output from change a18ebd6c439: vagrant@ubuntu-groovy:~$ g++ -v -save-temps -Wall --std=c++2a builder_simplified.cpp Using built-in specs. COLLECT_GCC=g++ COLLECT_LTO_WRAPPER=/home/vagrant/install-gcc/libexec/gcc/x86_64-pc-linux-gnu/11.0.1/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-git/configure --prefix=/home/vagrant/install-gcc --disable-nls --enable-languages=c,c++ --disable-multilib Thread model: posix Supported LTO compression algorithms: zlib gcc version 11.0.1 20210307 (experimental) (GCC) COLLECT_GCC_OPTIONS='-v' '-save-temps' '-Wall' '-std=c++20' '-shared-libgcc' '-mtune=generic' '-march=x86-64' '-dumpdir' 'a-' /home/vagrant/install-gcc/libexec/gcc/x86_64-pc-linux-gnu/11.0.1/cc1plus -E -quiet -v -imultiarch x86_64-linux-gnu -D_GNU_SOURCE builder_simplified.cpp -mtune=generic -march=x86-64 -std=c++20 -Wall -fpch-preprocess -o a-builder_simplified.ii ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu" ignoring nonexistent directory "/home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/../../../../x86_64-pc-linux-gnu/include" #include "..." search starts here: #include <...> search starts here: /home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/../../../../include/c++/11.0.1 /home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/../../../../include/c++/11.0.1/x86_64-pc-linux-gnu /home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/../../../../include/c++/11.0.1/backward /home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/include /usr/local/include /home/vagrant/install-gcc/include /home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/include-fixed /usr/include/x86_64-linux-gnu /usr/include End of search list. COLLECT_GCC_OPTIONS='-v' '-save-temps' '-Wall' '-std=c++20' '-shared-libgcc' '-mtune=generic' '-march=x86-64' '-dumpdir' 'a-' /home/vagrant/install-gcc/libexec/gcc/x86_64-pc-linux-gnu/11.0.1/cc1plus -fpreprocessed a-builder_simplified.ii -quiet -dumpdir a- -dumpbase builder_simplified.cpp -dumpbase-ext .cpp -mtune=generic -march=x86-64 -Wall -std=c++20 -version -o a-builder_simplified.s GNU C++20 (GCC) version 11.0.1 20210307 (experimental) (x86_64-pc-linux-gnu) compiled by GNU C version 11.0.1 20210307 (experimental), GMP version 6.1.0, MPFR version 3.1.4, MPC version 1.0.3, isl version isl-0.18-GMP GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096 GNU C++20 (GCC) version 11.0.1 20210307 (experimental) (x86_64-pc-linux-gnu) compiled by GNU C version 11.0.1 20210307 (experimental), GMP version 6.1.0, MPFR version 3.1.4, MPC version 1.0.3, isl version isl-0.18-GMP GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096 Compiler executable checksum: 95262a810cbe258ee31ada9b2568b963 COLLECT_GCC_OPTIONS='-v' '-save-temps' '-Wall' '-std=c++20' '-shared-libgcc' '-mtune=generic' '-march=x86-64' '-dumpdir' 'a-' as -v --64 -o a-builder_simplified.o a-builder_simplified.s GNU assembler version 2.35.1 (x86_64-linux-gnu) using BFD version (GNU Binutils for Ubuntu) 2.35.1 COMPILER_PATH=/home/vagrant/install-gcc/libexec/gcc/x86_64-pc-linux-gnu/11.0.1/:/home/vagrant/install-gcc/libexec/gcc/x86_64-pc-linux-gnu/11.0.1/:/home/vagrant/install-gcc/libexec/gcc/x86_64-pc-linux-gnu/:/home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/:/home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/ LIBRARY_PATH=/home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/:/home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/../../../../lib64/:/lib/x86_64-linux-gnu/:/lib/../lib64/:/usr/lib/x86_64-linux-gnu/:/usr/lib/../lib64/:/home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/../../../:/lib/:/usr/lib/ COLLECT_GCC_OPTIONS='-v' '-save-temps' '-Wall' '-std=c++20' '-shared-libgcc' '-mtune=generic' '-march=x86-64' '-dumpdir' 'a.' /home/vagrant/install-gcc/libexec/gcc/x86_64-pc-linux-gnu/11.0.1/collect2 -plugin /home/vagrant/install-gcc/libexec/gcc/x86_64-pc-linux-gnu/11.0.1/liblto_plugin.so -plugin-opt=/home/vagrant/install-gcc/libexec/gcc/x86_64-pc-linux-gnu/11.0.1/lto-wrapper -plugin-opt=-fresolution=a.res -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lc -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 /lib/x86_64-linux-gnu/crt1.o /lib/x86_64-linux-gnu/crti.o /home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/crtbegin.o -L/home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1 -L/home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/../../../../lib64 -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu -L/usr/lib/../lib64 -L/home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/../../.. a-builder_simplified.o -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /home/vagrant/install-gcc/lib/gcc/x86_64-pc-linux-gnu/11.0.1/crtend.o /lib/x86_64-linux-gnu/crtn.o COLLECT_GCC_OPTIONS='-v' '-save-temps' '-Wall' '-std=c++20' '-shared-libgcc' '-mtune=generic' '-march=x86-64' '-dumpdir' 'a.' vagrant@ubuntu-groovy:~$ ./a.out a.out: builder_simplified.cpp:46: int main(): Assertion `flags2[1]' failed. Aborted (core dumped)