re PR c++/39803 (Bogus 'unused value' warning on declarations of non-POD arrays)

        PR c++/39803
	* gcc/cp/init.c (build_vec_init): Set TREE_NO_WARNING on the
	compiler-generated INDIRECT_REF expression.
	* gcc/testsuite/g++.dg/warn/Wunused-14.C: New test.

From-SVN: r146454

gcc/cp/ChangeLog

+2009-04-20  Le-Chun Wu  <lcwu@google.com>
+
+	PR c++/39803
+	* init.c (build_vec_init): Set TREE_NO_WARNING on the
+	compiler-generated INDIRECT_REF expression.
+
 2009-04-20  Ian Lance Taylor  <iant@google.com>
 
 	* typeck.c (build_function_call_vec): New function.
@@ -34,7 +40,7 @@
 	* cp-tree.h (enum tsubst_flags): Rename from enum tsubst_flags_t.
 	(tsubst_flags_t): Change typedef from enum type to int.
 
-2009-04-16  Le-Chun Wu  <lcwu@google.com>
+2009-04-16  Paolo Bonzini  <bonzini@gnu.org>
 
 	* decl.c (check_initializer): Use TYPE_VECTOR_OPAQUE
 	instead of targetm.vector_opaque_p.

gcc/cp/init.c

@@ -2920,6 +2920,7 @@ build_vec_init (tree base, tree maxindex, tree init,
       atype = build_pointer_type (atype);
       stmt_expr = build1 (NOP_EXPR, atype, stmt_expr);
       stmt_expr = cp_build_indirect_ref (stmt_expr, NULL, complain);
+      TREE_NO_WARNING (stmt_expr) = 1;
     }
 
   current_stmt_tree ()->stmts_are_full_exprs_p = destroy_temps;

gcc/testsuite/ChangeLog

+2009-04-20  Le-Chun Wu  <lcwu@google.com>
+
+	PR c++/39803
+	* g++.dg/warn/Wunused-14.C: New test.
+
 2009-04-20  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gnat.dg/specs/small_alignment.ads: New test.

gcc/testsuite/g++.dg/warn/Wunused-14.C

+// Test that -Wunused should not emit a warning on the initialization of
+// non-POD arrays. See PR c++/39803.
+// { dg-do compile }
+// { dg-options "-Wunused" }
+
+#include <utility>
+
+using std::pair;
+
+int foo() {
+  pair<int, const char*> components[3]; // { dg-bogus "value computed is not used" }
+  components[0].first = 0;
+  return 0;
+}