[Bug libstdc++/110807] [13 Regression] Copy list initialisation of a vector raises a warning with -O2

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110807

--- Comment #12 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I don't think _M_offset can ever be out of range, it's always set by the
library code.

Doesn't the warning come from this line, which doesn't use _M_offset anyway?

        _Bit_type* __q = std::copy(__first._M_p, __last._M_p, __result._M_p);

So I'm not sure what we can do in the library to state the invariants in a way
the optimizer can understand them.