* pt.c (unify) [TEMPLATE_TYPE_PARM]: Allow VLA for C++0x 'auto'.

From-SVN: r177476

gcc/cp/ChangeLog

+2011-08-05  Jason Merrill  <jason@redhat.com>
+
+	* pt.c (unify) [TEMPLATE_TYPE_PARM]: Allow VLA for C++0x 'auto'.
+
 2011-08-04  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/49905

gcc/cp/pt.c

@@ -15932,10 +15932,11 @@ unify (tree tparms, tree targs, tree parm, tree arg, int strict,
 	     that were talking about variable-sized arrays (like
 	     `int[n]'), rather than arrays of unknown size (like
 	     `int[]').)  We'll get very confused by such a type since
-	     the bound of the array will not be computable in an
-	     instantiation.  Besides, such types are not allowed in
-	     ISO C++, so we can do as we please here.  */
-	  if (variably_modified_type_p (arg, NULL_TREE))
+	     the bound of the array is not constant, and therefore
+	     not mangleable.  Besides, such types are not allowed in
+	     ISO C++, so we can do as we please here.  We do allow
+	     them for 'auto' deduction, since that isn't ABI-exposed.  */
+	  if (!is_auto (parm) && variably_modified_type_p (arg, NULL_TREE))
 	    return unify_vla_arg (explain_p, arg);
 
 	  /* Strip typedefs as in convert_template_argument.  */

gcc/testsuite/ChangeLog

+2011-08-05  Jason Merrill  <jason@redhat.com>
+
+	* g++.dg/ext/vla11.C: New.
+
 2011-08-05  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/49984

gcc/testsuite/g++.dg/ext/vla11.C

+// Test that auto works with VLAs.
+// { dg-options -std=c++0x }
+
+void bar(int n)
+{
+  float loc2[n];
+  auto&& range = loc2;
+}