[Bug libstdc++/101361] Bogus -Wstringop-overread warning with -O3

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101361

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
And that change only helps the testcase in comment 1, not the original one in
comment 0.