[PATCH] Fix -Wstringop-overflow warning in 23_containers/vector/types/1.cc

[Sam James]

François Dumont <frs.dumont@gmail.com> writes:

> In C++98 this test fails with:

For this, and your other -Wfree-nonheap-object patches, could you see if
it helps with any of the bugs reported for both -Wstringop-overflow and
-Wfree-nonheap-object in libstdc++? There's a bunch of (possible) dupes
that it'd be worth tagging if any of them are applicable.

>
> Excess errors:
> /home/fdumont/dev/gcc/build/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/stl_algobase.h:452:
> warning: 'void* __builtin_memcpy(void*, const void*, long unsigned
> int)' writing between 2 and 9223372036854775806 bytes into a region of
> size 0 overflows the destination [-Wstringop-overflow=]
>
> The attached patch avoids this warning.
>
>     libstdc++: Fix -Wstringop-overflow warning coming from std::vector
>
>     Make vector<>::_M_range_insert implementation more transparent to
> the compiler checks.
>
>     Extend local copies of members to the whole method scope so that
> all branches benefit
>     from those.
>
>     libstdc++-v3/ChangeLog:
>
>             * include/bits/vector.tcc
>             (std::vector<>::_M_range_insert(iterator, _FwdIt, _FwdIt,
> forward_iterator_tag)):
>             Use local copies of members to call the different algorithms.
>
> Ok to commit if all tests passes ?
>
> François
>
> [2. text/plain; vector_range_insert_patch.txt]...