re PR c++/65695 (NSDMI calling constexpr constructor with pointer-to-member is…

re PR c++/65695 (NSDMI calling constexpr constructor with pointer-to-member is not a constant expression)

	PR c++/65695
	* cvt.c (cp_fold_convert): Avoid wrapping PTRMEM_CST in NOP_EXPR.

From-SVN: r222097

gcc/cp/ChangeLog

 2015-04-14  Jason Merrill  <jason@redhat.com>
 
+	PR c++/65695
+	* cvt.c (cp_fold_convert): Avoid wrapping PTRMEM_CST in NOP_EXPR.
+
 	PR c++/65721
 	* name-lookup.c (do_class_using_decl): Complain about specifying
 	the current class even if there are dependent bases.

gcc/cp/cvt.c

@@ -603,8 +603,20 @@ ignore_overflows (tree expr, tree orig)
 tree
 cp_fold_convert (tree type, tree expr)
 {
-  tree conv = fold_convert (type, expr);
-  conv = ignore_overflows (conv, expr);
+  tree conv;
+  if (TREE_TYPE (expr) == type)
+    conv = expr;
+  else if (TREE_CODE (expr) == PTRMEM_CST)
+    {
+      /* Avoid wrapping a PTRMEM_CST in NOP_EXPR.  */
+      conv = copy_node (expr);
+      TREE_TYPE (conv) = type;
+    }
+  else
+    {
+      conv = fold_convert (type, expr);
+      conv = ignore_overflows (conv, expr);
+    }
   return conv;
 }
 

gcc/testsuite/g++.dg/cpp0x/constexpr-ptrmem4.C

+// PR c++/65695
+// { dg-do compile { target c++11 } }
+
+struct Foo;
+
+struct Bar
+{
+    using MemberFuncT = int (Foo::*)();
+
+    MemberFuncT h_;
+    constexpr Bar(MemberFuncT h) : h_{h}
+    {
+    }
+};
+
+struct Foo
+{
+    int test()
+    {
+        return -1;
+    }
+
+    static constexpr Bar bar {&Foo::test};
+};
+
+constexpr Bar Foo::bar;