[gcc r15-9017] libstdc++: Add testcase for bogus -Wstringop-overflow in std::vector [PR117983]

[Jonathan Wakely]

https://gcc.gnu.org/g:878812b6f6905774ab37cb78903e3e11bf1c508c

commit r15-9017-g878812b6f6905774ab37cb78903e3e11bf1c508c
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Mar 28 21:46:46 2025 +0000

    libstdc++: Add testcase for bogus -Wstringop-overflow in std::vector [PR117983]
    
    This was fixed on trunk by r15-4473-g3abe751ea86e34, just add the
    testcase.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/117983
            * testsuite/23_containers/vector/modifiers/insert/117983.cc: New
            test.

Diff:
---
 .../23_containers/vector/modifiers/insert/117983.cc     | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/libstdc++-v3/testsuite/23_containers/vector/modifiers/insert/117983.cc b/libstdc++-v3/testsuite/23_containers/vector/modifiers/insert/117983.cc
new file mode 100644
index 000000000000..e6027a677eed
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/vector/modifiers/insert/117983.cc
@@ -0,0 +1,17 @@
+// { dg-options "-O3 -Werror=stringop-overflow" }
+// { dg-do compile }
+
+// PR libstdc++/117983
+// -Wstringop-overflow false positive for __builtin_memmove from vector::insert
+
+#include <vector>
+
+typedef std::vector<unsigned char> bytes;
+
+void push(bytes chunk, bytes& data) {
+  if (data.empty()) {
+    data.swap(chunk);
+  } else {
+    data.insert(data.end(), chunk.begin(), chunk.end());
+  }
+}