Tested powerpc64le-linux, pushed to trunk.
The compiler warns about the loop in deque::_M_range_initialize because
it doesn't know that the number of nodes has already been correctly
sized to match the size of the input. Use __builtin_unreachable to tell
it that the loop will never be entered if the number of elements is
smaller than a single node.
libstdc++-v3/ChangeLog:
PR libstdc++/100516
* include/bits/deque.tcc (_M_range_initialize<ForwardIterator>):
Add __builtin_unreachable to loop.
* testsuite/23_containers/deque/100516.cc: New test.
---
libstdc++-v3/include/bits/deque.tcc | 3 +++
.../testsuite/23_containers/deque/100516.cc | 14 ++++++++++++++
2 files changed, 17 insertions(+)
create mode 100644 libstdc++-v3/testsuite/23_containers/deque/100516.cc
diff --git a/libstdc++-v3/include/bits/deque.tcc
b/libstdc++-v3/include/bits/deque.tcc
index 80f1813bc76..03e0a505e14 100644
--- a/libstdc++-v3/include/bits/deque.tcc
+++ b/libstdc++-v3/include/bits/deque.tcc
@@ -454,6 +454,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
__cur_node < this->_M_impl._M_finish._M_node;
++__cur_node)
{
+ if (__n < _S_buffer_size())
+ __builtin_unreachable(); // See PR 100516
+
_ForwardIterator __mid = __first;
std::advance(__mid, _S_buffer_size());
std::__uninitialized_copy_a(__first, __mid, *__cur_node,
diff --git a/libstdc++-v3/testsuite/23_containers/deque/100516.cc
b/libstdc++-v3/testsuite/23_containers/deque/100516.cc
new file mode 100644
index 00000000000..ef32ae10545
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/deque/100516.cc
@@ -0,0 +1,14 @@
+// { dg-options "-O2 -Wstringop-overread" }
+// { dg-do compile { target c++11 } }
+
+// Bug 100516
+// Unexpected -Wstringop-overread in deque<char> initialization from empty
+// initializer_list
+
+#include <deque>
+
+void f()
+{
+ std::initializer_list<char> il{};
+ std::deque<char>{il};
+}
--
2.34.1
