--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/g++.dg/ext/attr-copy.C	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,82 @@
+/* PR middle-end/88546 - Copy attribute unusable for weakrefs
+   { dg-do compile }
+   { dg-options "-O1 -Wall -fdump-tree-optimized" }
+   { dg-require-weak "" } */
+
+#define ATTR(...)   __attribute__ ((__VA_ARGS__))
+#define ASRT(expr)   _Static_assert (expr, #expr)
+
+extern "C" {
+
+  ATTR (leaf, nothrow) int
+  fnothrow ()
+  {
+    return 0;
+  }
+
+  static __typeof__ (fnothrow)
+    ATTR (weakref ("fnothrow"), copy (fnothrow))
+    alias_fnothrow;
+
+
+  ATTR (leaf) int
+  fthrow_none () throw ()
+  {
+    return 0;
+  }
+
+  // Verify that no warning is issued for the alias having less
+  // restrictive attributes than the target: nothrow.
+  static __typeof (fthrow_none)
+    ATTR (weakref ("fthrow_none"), copy (fthrow_none))
+    alias_fthrow_none;
+
+  // Same as above but with no definition of the target.
+  ATTR (leaf) int
+  fthrow_none_nodef () throw ();
+
+  static __typeof (fthrow_none_nodef)
+    ATTR (weakref ("fthrow_none_nodef"), copy (fthrow_none_nodef))
+    alias_fthrow_none_nodef;
+
+  // And again but without using typeof to make sure the nothrow
+  // bit is copied by attribute copy alone.
+  static int
+  ATTR (weakref ("fthrow_none_nodef"), copy (fthrow_none_nodef))
+    alias_fthrow_none_nodef_func ();
+}
+
+
+struct UsrClass
+{
+  ~UsrClass ();
+};
+
+// Verify that the nothrow attribute/bit was copied to the alias and
+// that no exception handling code is emitted in any of these calls.
+
+int call_alias_fnothrow ()
+{
+  UsrClass usr;
+  return alias_fnothrow ();
+}
+
+int call_alias_fthrow_none ()
+{
+  UsrClass usr;
+  return alias_fthrow_none ();
+}
+
+int call_alias_fthrow_none_nodef ()
+{
+  UsrClass usr;
+  return alias_fthrow_none_nodef ();
+}
+
+int call_alias_fthrow_none_nodef_func ()
+{
+  UsrClass usr;
+  return alias_fthrow_none_nodef_func ();
+}
+
+// { dg-final { scan-tree-dump-not "__builtin_unwind" "optimized" } }