Avoid crashing on erroneous static_assert usage

When working on something else, I noticed that failing to provide the
second argument to the static_assert operator would lead to an ICE.

Fixed thus, and tested against trunk on x86_64-unknown-linux-gnu.

gcc/cp/

	* semantics.c (finish_static_assert): Don't crash on erroneous
	message or condition.

gcc/testsuite/

	* g++.dg/cpp0x/static_assert8.C: New test.

From-SVN: r190182

gcc/cp/ChangeLog

+2012-08-06  Dodji Seketeli  <dodji@redhat.com>
+
+	Avoid crashing on erroneous static_assert usage
+	* semantics.c (finish_static_assert): Don't crash on erroneous
+	message or condition.
+
 2012-08-06  Marc Glisse  <marc.glisse@inria.fr>
 	    Paolo Carlini  <paolo.carlini@oracle.com>
 

gcc/cp/semantics.c

@@ -5099,6 +5099,12 @@ void
 finish_static_assert (tree condition, tree message, location_t location, 
                       bool member_p)
 {
+  if (message == NULL_TREE
+      || message == error_mark_node
+      || condition == NULL_TREE
+      || condition == error_mark_node)
+    return;
+
   if (check_for_bare_parameter_packs (condition))
     condition = error_mark_node;
 

gcc/testsuite/ChangeLog

+2012-08-06  Dodji Seketeli  <dodji@redhat.com>
+
+	Avoid crashing on erroneous static_assert usage
+	* g++.dg/cpp0x/static_assert8.C: New test.
+
 2012-08-06  Jason Merrill  <jason@redhat.com>
 
 	* g++.dg/cpp0x/sfinae38.C: New.

gcc/testsuite/g++.dg/cpp0x/static_assert8.C

+// { dg-do compile { target c++11 } }
+
+static_assert (1 == 0); // { dg-error "expected (string-literal|',') before" }
+
+static_assert (1 == 0,); // { dg-error "expected string-literal before '\\)'" }
+
+static_assert (1 == 0, "oops"); // { dg-error "static assertion failed" }