re PR c++/54583 (Spurious warning: value computed is not used with variable-size array)

/cp
2012-10-31  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/54583
	* tree.c (build_cplus_array_type): Set TREE_NO_WARNING on the
	TYPE_SIZE of VLAs.

/testsuite
2012-10-31  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/54583
	* g++.dg/ext/vla13.C: New.

From-SVN: r193043

gcc/cp/ChangeLog

+2012-10-31  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/54583
+	* tree.c (build_cplus_array_type): Set TREE_NO_WARNING on the
+	TYPE_SIZE of VLAs.
+
 2012-10-31  Dodji Seketeli  <dodji@redhat.com>
 
 	PR c++/54955

gcc/cp/tree.c

@@ -824,6 +824,10 @@ build_cplus_array_type (tree elt_type, tree index_type)
 	}
     }
 
+  /* Avoid spurious warnings with VLAs (c++/54583).  */
+  if (TYPE_SIZE (t) && EXPR_P (TYPE_SIZE (t)))
+    TREE_NO_WARNING (TYPE_SIZE (t)) = 1;
+
   /* Push these needs up so that initialization takes place
      more easily.  */
   TYPE_NEEDS_CONSTRUCTING (t)

gcc/testsuite/ChangeLog

+2012-10-31  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/54583
+	* g++.dg/ext/vla13.C: New.
+
 2012-10-31  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR middle-end/55150

gcc/testsuite/g++.dg/ext/vla13.C

+// PR c++/54583
+// { dg-options "-Wunused-value" }
+
+void fred()
+{
+  int n=10;
+  double (*x)[n];
+}