typeck2.c (merge_exception_specifiers): Adjust merging of throw() and noexcept(true).

	* typeck2.c (merge_exception_specifiers): Adjust merging of
	throw() and noexcept(true).

From-SVN: r160308

gcc/cp/ChangeLog

 2010-06-04  Jason Merrill  <jason@redhat.com>
 
+	* typeck2.c (merge_exception_specifiers): Adjust merging of
+	throw() and noexcept(true).
+
 	* pt.c (value_dependent_expression_p) [NOEXCEPT_EXPR]: Avoid
 	using an uninitialized variable.
 

gcc/cp/typeck2.c

@@ -1721,17 +1721,14 @@ merge_exception_specifiers (tree list, tree add)
 {
   if (!list || !add)
     return NULL_TREE;
-  /* A noexcept(true) spec takes precedence over a throw() spec.
+  /* For merging noexcept(true) and throw(), take the more recent one (LIST).
      A throw(type-list) spec takes precedence over a noexcept(false) spec.
      Any other noexcept-spec should only be merged with an equivalent one.
-     So the !TREE_VALUE code is correct for the latter two cases.  */
-  else if (list == noexcept_true_spec
-	   || add == noexcept_true_spec)
-    return noexcept_true_spec;
-  else if (!TREE_VALUE (list))
-    return add;
+     So the !TREE_VALUE code below is correct for all cases.  */
   else if (!TREE_VALUE (add))
     return list;
+  else if (!TREE_VALUE (list))
+    return add;
   else
     {
       tree orig_list = list;

gcc/testsuite/ChangeLog

 2010-06-04  Jason Merrill  <jason@redhat.com>
 
+	* g++.dg/cpp0x/noexcept06.C: New.
+	* g++.dg/cpp0x/noexcept07.C: New.
+
 	* g++.dg/cpp0x/noexcept01.C: New.
 	* g++.dg/cpp0x/noexcept02.C: New.
 	* g++.dg/cpp0x/noexcept03.C: New.

gcc/testsuite/g++.dg/cpp0x/noexcept06.C

+// Test that checking of a nothrow specification uses the one on the
+// definition.
+// { dg-options "-std=c++0x" }
+// { dg-do run }
+
+#include <exception>
+#include <cstdlib>
+
+void my_unexpected ()
+{
+  std::abort ();
+}
+void my_terminate ()
+{
+  std::exit (0);
+}
+
+void f() throw();
+void f() noexcept
+{
+  throw 1;
+}
+
+int main()
+{
+  std::set_terminate (my_terminate);
+  f();
+  return 1;
+}

gcc/testsuite/g++.dg/cpp0x/noexcept07.C

+// Test that checking of a nothrow specification uses the one on the
+// definition.
+// { dg-options "-std=c++0x" }
+// { dg-do run }
+
+#include <exception>
+#include <cstdlib>
+
+void my_unexpected ()
+{
+  std::exit (0);
+}
+
+void f() noexcept;
+void f() throw()
+{
+  throw 1;
+}
+
+int main()
+{
+  std::set_unexpected (my_unexpected);
+  f();
+  return 1;
+}