In this case, we need to tell the compiler that the current size is not
larger than the new size so that all the existing elements can be copied
to the new storage. This avoids bogus warnings about overflowing the new
storage when the compiler can't tell that that cannot happen.
We might as well also hoist the loads of begin() and end() before the
allocation too. All callers will have loaded at least begin() before
calling _M_reallocate.
libstdc++-v3/ChangeLog:
PR libstdc++/110498
* include/bits/vector.tcc (vector<bool, A>::_M_reallocate):
Hoist loads of begin() and end() before allocation and use them
to state an unreachable condition.
* testsuite/23_containers/vector/bool/capacity/110498.cc: New
test.
---
Tested x86_64-linux.
libstdc++-v3/include/bits/vector.tcc | 5 ++++-
.../23_containers/vector/bool/capacity/110498.cc | 14 ++++++++++++++
2 files changed, 18 insertions(+), 1 deletion(-)
create mode 100644
libstdc++-v3/testsuite/23_containers/vector/bool/capacity/110498.cc
diff --git a/libstdc++-v3/include/bits/vector.tcc
b/libstdc++-v3/include/bits/vector.tcc
index 29aa63e4742..7a92f34ec64 100644
--- a/libstdc++-v3/include/bits/vector.tcc
+++ b/libstdc++-v3/include/bits/vector.tcc
@@ -1106,9 +1106,12 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
vector<bool, _Alloc>::
_M_reallocate(size_type __n)
{
+ const iterator __begin = begin(), __end = end();
+ if (size_type(__end - __begin) > __n)
+ __builtin_unreachable();
_Bit_pointer __q = this->_M_allocate(__n);
iterator __start(std::__addressof(*__q), 0);
- iterator __finish(_M_copy_aligned(begin(), end(), __start));
+ iterator __finish(_M_copy_aligned(__begin, __end, __start));
this->_M_deallocate();
this->_M_impl._M_start = __start;
this->_M_impl._M_finish = __finish;
diff --git
a/libstdc++-v3/testsuite/23_containers/vector/bool/capacity/110498.cc
b/libstdc++-v3/testsuite/23_containers/vector/bool/capacity/110498.cc
new file mode 100644
index 00000000000..70c4bf6a954
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/vector/bool/capacity/110498.cc
@@ -0,0 +1,14 @@
+// { dg-options "-O3 -Werror=array-bounds
-fno-assume-sane-operators-new-delete" }
+// { dg-do compile }
+
+#include <vector>
+
+void f(std::vector<bool>& v)
+{
+ // Warning emitted when set to any number in the range [1,64].
+ const std::size_t reserve_size = 30;
+
+ v.reserve(reserve_size);
+ v.push_back(0);
+}
+
--
2.49.0
