1 files changed, 39 insertions, 0 deletions
diff --git a/gcc/testsuite/g++.dg/init/copy7.C b/gcc/testsuite/g++.dg/init/copy7.C
new file mode 100644
index 000000000..20e1e47db
--- /dev/null
+++ b/gcc/testsuite/g++.dg/init/copy7.C
@@ -0,0 +1,39 @@
+// PR c++/39480
+// It isn't always safe to call memcpy with identical arguments.
+// { dg-do run }
+
+extern "C" void abort();
+extern "C" void *
+memcpy(void *dest, void *src, __SIZE_TYPE__ n)
+{
+  if (dest == src)
+    abort();
+  else
+    {
+      __SIZE_TYPE__ i;
+      for (i = 0; i < n; i++)
+        ((char *)dest)[i] = ((const char*)src)[i];
+    }
+}
+
+struct A
+{
+  double d[10];
+};
+
+struct B: public A
+{
+  char bc;
+};
+
+B b;
+
+void f(B *a1, B* a2)
+{
+  *a1 = *a2;
+}
+
+int main()
+{
+  f(&b,&b);
+}