PR c++/71513 - alignas on member enum in template

	* pt.c (tsubst_attributes): Fix loop logic.

From-SVN: r238392

gcc/cp/ChangeLog

 2016-07-15  Jason Merrill  <jason@redhat.com>
 
+	PR c++/71513
+	* pt.c (tsubst_attributes): Fix loop logic.
+
 	PR c++/71604
 	PR c++/54430
 	* parser.c (cp_parser_range_for): Modify IDENTIFIER_BINDING directly.

gcc/cp/pt.c

@@ -9713,20 +9713,23 @@ tsubst_attributes (tree attributes, tree args,
       }
 
   if (last_dep)
-    for (tree *p = &attributes; *p; p = &TREE_CHAIN (*p))
+    for (tree *p = &attributes; *p; )
       {
 	tree t = *p;
 	if (ATTR_IS_DEPENDENT (t))
 	  {
 	    tree subst = tsubst_attribute (t, NULL, args, complain, in_decl);
-	    if (subst == t)
-	      continue;
-	    *p = subst;
-	    do
-	      p = &TREE_CHAIN (*p);
-	    while (*p);
-	    *p = TREE_CHAIN (t);
+	    if (subst != t)
+	      {
+		*p = subst;
+		do
+		  p = &TREE_CHAIN (*p);
+		while (*p);
+		*p = TREE_CHAIN (t);
+		continue;
+	      }
 	  }
+	p = &TREE_CHAIN (*p);
       }
 
   return attributes;

gcc/testsuite/g++.dg/cpp0x/alignas7.C

+// PR c++/71513
+// { dg-do compile { target c++11 } }
+
+template < int N, typename T >
+struct A
+{ 
+  enum alignas (N) E : T;
+};
+
+#define SA(X) static_assert((X), #X)
+
+constexpr int al = alignof(double);
+SA(alignof(A<al,char>::E) == al);