[Bug libstdc++/67214] undefined behaviour in std::num_get::_M_extract_int()

[ryxi at stu dot xidian.edu.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67214

Xi Ruoyao <ryxi at stu dot xidian.edu.cn> changed:

           What    |Removed                     |Added
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                 CC|                            |ryxi at stu dot xidian.edu.cn

--- Comment #1 from Xi Ruoyao <ryxi at stu dot xidian.edu.cn> ---
For GCC 5/6/7 I can't reproduce this since the target code is in libstdc++.so
and there the ubsan can't sanitize them.  But it seems a real undefined
behaviour.

BTW, -Woverflow doesn't warn for this in the building of libstdc++ (or this
bug should have been detected and fixed). I think there are still improvements
of -Woverflow to do.