[Bug c++/99460] [C++20] Template with complex non-type argument re-uses different specialisation

["gcc.mexon at spamgourmet dot com" <gcc-bugzilla@gcc.gnu.org>]

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)