[Bug c++/99386] std::variant overhead much larger compared to clang

[mail at milianw dot de via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99386

--- Comment #2 from Milian Wolff <mail at milianw dot de> ---
in both cases libstdc++ is being used:

```
gcc:
        linux-vdso.so.1 (0x00007ffdc9f93000)
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007f1449b2d000)
        libm.so.6 => /usr/lib/libm.so.6 (0x00007f14499e8000)
        libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007f14499ce000)
        libc.so.6 => /usr/lib/libc.so.6 (0x00007f1449801000)
        /lib64/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2
(0x00007f1449d40000)

clang:
        linux-vdso.so.1 (0x00007fff5854f000)
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x00007fd9b190f000)
        libm.so.6 => /usr/lib/libm.so.6 (0x00007fd9b17ca000)
        libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x00007fd9b17b0000)
        libc.so.6 => /usr/lib/libc.so.6 (0x00007fd9b15e3000)
        /lib64/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2
(0x00007fd9b1b22000)
```

I just tried setting `-O3 -finline-limit=5000`, but the performance numbers
don't really change much. Is there anything else I should be trying out?