PR c++/84665 - ICE with array of empty class.

	* decl2.c (cp_check_const_attributes): Use fold_non_dependent_expr.

From-SVN: r259132

gcc/cp/ChangeLog

 2018-04-05  Jason Merrill  <jason@redhat.com>
 
+	PR c++/84665 - ICE with array of empty class.
+	* decl2.c (cp_check_const_attributes): Use fold_non_dependent_expr.
+
 	PR c++/85228 - ICE with lambda in enumerator in template.
 	* pt.c (bt_instantiate_type_proc): Don't assume
 	CLASSTYPE_TEMPLATE_INFO is non-null.

gcc/cp/decl2.c

@@ -1416,7 +1416,7 @@ cp_check_const_attributes (tree attributes)
 	{
 	  tree expr = TREE_VALUE (arg);
 	  if (EXPR_P (expr))
-	    TREE_VALUE (arg) = maybe_constant_value (expr);
+	    TREE_VALUE (arg) = fold_non_dependent_expr (expr);
 	}
     }
 }

gcc/testsuite/g++.dg/ext/attr-noinline-4.C

+// PR c++/84665
+
+struct S {} a[1];
+
+template <int N>
+void
+foo ()
+{
+  __attribute__ ((noinline (a[0]))) int c = 0; // { dg-error "wrong number of arguments" }
+}