re PR c++/51526 ([C++11][constexpr] constexpr delegating constructor should be accepted)

PR c++/51526
	* semantics.c (build_data_member_initialization): Handle
	delegating constructor.
	(build_constexpr_constructor_member_initializers): Likewise.

From-SVN: r182499

gcc/cp/ChangeLog

@@ -1,5 +1,10 @@
 2011-12-19  Jason Merrill  <jason@redhat.com>
 
+	PR c++/51526
+	* semantics.c (build_data_member_initialization): Handle
+	delegating constructor.
+	(build_constexpr_constructor_member_initializers): Likewise.
+
 	PR c++/51553
 	* cp-tree.h (LOOKUP_LIST_INIT_CTOR): Rename from
 	LOOKUP_NO_COPY_CTOR_CONVERSION.

gcc/cp/semantics.c

@@ -5801,6 +5801,12 @@ build_data_member_initialization (tree t, VEC(constructor_elt,gc) **vec)
 	     the const_cast.  */
 	  member = op;
 	}
+      else if (op == current_class_ptr
+	       && (same_type_ignoring_top_level_qualifiers_p
+		   (TREE_TYPE (TREE_TYPE (member)),
+		    current_class_type)))
+	/* Delegating constructor.  */
+	member = op;
       else
 	{
 	  /* We don't put out anything for an empty base.  */
@@ -5907,7 +5913,20 @@ build_constexpr_constructor_member_initializers (tree type, tree body)
   else
     gcc_assert (errorcount > 0);
   if (ok)
-    return build_constructor (type, vec);
+    {
+      if (VEC_length (constructor_elt, vec) > 0)
+	{
+	  /* In a delegating constructor, return the target.  */
+	  constructor_elt *ce = VEC_index (constructor_elt, vec, 0);
+	  if (ce->index == current_class_ptr)
+	    {
+	      body = ce->value;
+	      VEC_free (constructor_elt, gc, vec);
+	      return body;
+	    }
+	}
+      return build_constructor (type, vec);
+    }
   else
     return error_mark_node;
 }

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2011-12-19  Jason Merrill  <jason@redhat.com>
+
+	PR c++/51526
+	* g++.dg/cpp0x/constexpr-delegating.C: New.
+
 2011-12-19  Sandra Loosemore  <sandra@codesourcery.com>
 	    Tom de Vries <tom@codesourcery.com>
 

gcc/testsuite/g++.dg/cpp0x/constexpr-delegating.C

@@ -0,0 +1,15 @@
+// PR c++/51526
+// { dg-options -std=c++0x }
+
+const int j = 42;
+
+struct S {
+  int i;
+  constexpr S(int i) : i(i) {}
+  constexpr S() : S(j) {}
+};
+
+constexpr S s{};
+
+#define SA(X) static_assert((X),#X)
+SA(s.i == 42);