libstdc++: Remove unused variable

https://builder.sourceware.org/buildbot/#/builders/312/builds/3547
shows
In file included from /home/builder/shared/sw3bb1/worker/gcc-fullest-debian-amd64/gcc-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/include/deque:72,
                 from /home/builder/shared/sw3bb1/worker/gcc-fullest-debian-amd64/gcc-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/include/stack:68,
                 from ../../gcc/gcc/cobol/cobol-system.h:52,
                 from ../../gcc/gcc/cobol/lexio.cc:33:
/home/builder/shared/sw3bb1/worker/gcc-fullest-debian-amd64/gcc-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/include/bits/deque.tcc: In instantiation of ‘std::_Deque_iterator<_OTp, _OTp&, _OTp*> std::__uninitialized_copy_a(_Deque_iterator<_Tp, _Ref, _Ptr>, _Deque_iterator<_Tp, _Ref, _Ptr>, _Deque_iterator<_OTp, _OTp&, _OTp*>, allocator<_Tp>&) [with _ITp = source_format_t; _IRef = const source_format_t&; _IPtr = const source_format_t*; _OTp = source_format_t; _Tp = source_format_t]’:
/home/builder/shared/sw3bb1/worker/gcc-fullest-debian-amd64/gcc-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/include/bits/stl_deque.h:922:36:   required from ‘std::deque<_Tp, _Alloc>::deque(const std::deque<_Tp, _Alloc>&) [with _Tp = source_format_t; _Alloc = std::allocator<source_format_t>]’
  922 |       { std::__uninitialized_copy_a(__x.begin(), __x.end(),
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
  923 |                                     this->_M_impl._M_start,
      |                                     ~~~~~~~~~~~~~~~~~~~~~~~
  924 |                                     _M_get_Tp_allocator()); }
      |                                     ~~~~~~~~~~~~~~~~~~~~~~
/home/builder/shared/sw3bb1/worker/gcc-fullest-debian-amd64/gcc-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/include/bits/stl_stack.h:107:11:   required from here
  107 |     class stack
      |           ^~~~~
/home/builder/shared/sw3bb1/worker/gcc-fullest-debian-amd64/gcc-build/prev-x86_64-pc-linux-gnu/libstdc++-v3/include/bits/deque.tcc:1577:19: error: unused variable ‘__sres’ [-Werror=unused-variable]
 1577 |             _OTp* __sres = __result._M_cur;
      |                   ^~~~~~
cc1plus: all warnings being treated as errors
make[3]: *** [Makefile:1218: cobol/lexio.o] Error 1

There is indeed an unused variable introduced in r16-8142.

The following patch removes it.

2026-07-28  Jakub Jelinek  <jakub@redhat.com>

	* include/bits/deque.tcc (std::__uninitialized_copy_a): Remove unused
	variable __sres.

diff --git a/libstdc++-v3/include/bits/deque.tcc b/libstdc++-v3/include/bits/deque.tcc
index b35f268b0db1bf0f89e7a79cd692b63d72e7198c..df4be0802124b78129022b28d144b963998e7551 100644 (file)
--- a/libstdc++-v3/include/bits/deque.tcc
+++ b/libstdc++-v3/include/bits/deque.tcc
@@ -1574,7 +1574,6 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
              __n = __last._M_cur - __from;
            else
              __n = __first._M_last - __from;
-           _OTp* __sres = __result._M_cur;
            __n = std::min<ptrdiff_t>(__n, __result._M_last - __result._M_cur);
            std::uninitialized_copy(__from, __from + __n, __result._M_cur);
            __first += __n;