re PR c++/59645 (ICE with covariant return and volatile)

	PR c++/59645
	* cgraphunit.c (expand_thunk): Copy volatile arg to a temporary.

From-SVN: r207301

gcc/ChangeLog

+2014-01-30  Jason Merrill  <jason@redhat.com>
+
+	PR c++/59645
+	* cgraphunit.c (expand_thunk): Copy volatile arg to a temporary.
+
 2014-01-30  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/59951

gcc/cgraphunit.c

@@ -1592,7 +1592,17 @@ expand_thunk (struct cgraph_node *node, bool output_asm_thunks)
 
       if (nargs)
         for (i = 1, arg = DECL_CHAIN (a); i < nargs; i++, arg = DECL_CHAIN (arg))
-	  vargs.quick_push (arg);
+	  {
+	    tree tmp = arg;
+	    if (!is_gimple_val (arg))
+	      {
+		tmp = create_tmp_reg (TYPE_MAIN_VARIANT
+				      (TREE_TYPE (arg)), "arg");
+		gimple stmt = gimple_build_assign (tmp, arg);
+		gsi_insert_after (&bsi, stmt, GSI_NEW_STMT);
+	      }
+	    vargs.quick_push (tmp);
+	  }
       call = gimple_build_call_vec (build_fold_addr_expr_loc (0, alias), vargs);
       node->callees->call_stmt = call;
       gimple_call_set_from_thunk (call, true);

gcc/testsuite/g++.dg/inherit/covariant21.C

+// PR c++/59645
+
+struct A { virtual ~A(); };
+struct B { virtual ~B(); };
+struct C : A, B {};
+
+struct X
+{
+  virtual B* foo(volatile int);
+};
+
+struct Y : X
+{
+  virtual C* foo(volatile int);
+};
+
+C* Y::foo(volatile int) { return 0; }