PR c++/85618 - ICE with initialized VLA.

* tree.c (vla_type_p): New.
	* typeck2.c (store_init_value, split_nonconstant_init_1): Check it
	rather than array_of_runtime_bound_p.

From-SVN: r260012

gcc/cp/ChangeLog

@@ -1,3 +1,10 @@
+2018-05-07  Jason Merrill  <jason@redhat.com>
+
+	PR c++/85618 - ICE with initialized VLA.
+	* tree.c (vla_type_p): New.
+	* typeck2.c (store_init_value, split_nonconstant_init_1): Check it
+	rather than array_of_runtime_bound_p.
+
 2018-05-05  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* cvt.c (ocp_convert): Early handle the special case of a

gcc/cp/cp-tree.h

@@ -7097,6 +7097,7 @@ extern tree get_target_expr_sfinae		(tree, tsubst_flags_t);
 extern tree build_cplus_array_type		(tree, tree);
 extern tree build_array_of_n_type		(tree, int);
 extern bool array_of_runtime_bound_p		(tree);
+extern bool vla_type_p				(tree);
 extern tree build_array_copy			(tree);
 extern tree build_vec_init_expr			(tree, tree, tsubst_flags_t);
 extern void diagnose_non_constexpr_vec_init	(tree);

gcc/cp/tree.c

@@ -1051,8 +1051,10 @@ build_array_of_n_type (tree elt, int n)
   return build_cplus_array_type (elt, build_index_type (size_int (n - 1)));
 }
 
-/* True iff T is an N3639 array of runtime bound (VLA).  These were
-   approved for C++14 but then removed.  */
+/* True iff T is an N3639 array of runtime bound (VLA).  These were approved
+   for C++14 but then removed.  This should only be used for N3639
+   specifically; code wondering more generally if something is a VLA should use
+   vla_type_p.  */
 
 bool
 array_of_runtime_bound_p (tree t)
@@ -1069,6 +1071,23 @@ array_of_runtime_bound_p (tree t)
 	  || (!value_dependent_expression_p (max) && !TREE_CONSTANT (max)));
 }
 
+/* True iff T is a variable length array.  */
+
+bool
+vla_type_p (tree t)
+{
+  for (; t && TREE_CODE (t) == ARRAY_TYPE;
+       t = TREE_TYPE (t))
+    if (tree dom = TYPE_DOMAIN (t))
+      {
+	tree max = TYPE_MAX_VALUE (dom);
+	if (!potential_rvalue_constant_expression (max)
+	    || (!value_dependent_expression_p (max) && !TREE_CONSTANT (max)))
+	  return true;
+      }
+  return false;
+}
+
 /* Return a reference type node referring to TO_TYPE.  If RVAL is
    true, return an rvalue reference type, otherwise return an lvalue
    reference type.  If a type node exists, reuse it, otherwise create

gcc/cp/typeck2.c

@@ -611,7 +611,7 @@ split_nonconstant_init_1 (tree dest, tree init)
       array_type_p = true;
       if ((TREE_SIDE_EFFECTS (init)
 	   && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
-	  || array_of_runtime_bound_p (type))
+	  || vla_type_p (type))
 	{
 	  /* For an array, we only need/want a single cleanup region rather
 	     than one per element.  */
@@ -861,7 +861,7 @@ store_init_value (tree decl, tree init, vec<tree, va_gc>** cleanups, int flags)
      will perform the dynamic initialization.  */
   if (value != error_mark_node
       && (TREE_SIDE_EFFECTS (value)
-	  || array_of_runtime_bound_p (type)
+	  || vla_type_p (type)
 	  || ! reduced_constant_expression_p (value)))
     return split_nonconstant_init (decl, value);
   /* If the value is a constant, just put it in DECL_INITIAL.  If DECL

gcc/testsuite/g++.dg/ext/vla20.C

@@ -0,0 +1,6 @@
+// PR c++/85618
+// { dg-additional-options "-Wno-vla" }
+
+  void function(int size) {
+     bool myArray[size][size] = {};
+  }