re PR c++/28879 (ICE with VLA in template function)

        PR c++/28879
        * parser.c (cp_parser_direct_declarator): In a template, wrap
        non-constant expression in NOP_EXPR with TREE_SIDE_EFFECTS set.
        * pt.c (tsubst): Preserve it in a partial instantiation.
        (dependent_type_p_r): Don't check value_dependent_expression_p.
        * decl.c (compute_array_index_type): Don't check
        value_dependent_expression_p if TREE_SIDE_EFFECTS.

From-SVN: r144988

1 files changed, 14 insertions, 5 deletions

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 9a6ab02..a96e606 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -7179,13 +7179,22 @@ compute_array_index_type (tree name, tree size)
       type = TREE_TYPE (size);
     }
 
-  if (value_dependent_expression_p (size))
-    {
-      /* We cannot do any checking for a value-dependent SIZE. Just
-	 build the index type and mark that it requires structural
-	 equality checks.  */
+  /* We can only call value_dependent_expression_p on integral constant
+     expressions; the parser adds a dummy NOP_EXPR with TREE_SIDE_EFFECTS
+     set if this isn't one.  */
+  if (processing_template_decl
+      && (TREE_SIDE_EFFECTS (size) || value_dependent_expression_p (size)))
+    {
+      /* We cannot do any checking for a SIZE that isn't known to be
+	 constant. Just build the index type and mark that it requires
+	 structural equality checks.  */
       itype = build_index_type (build_min (MINUS_EXPR, sizetype,
 					   size, integer_one_node));
+      if (!TREE_SIDE_EFFECTS (size))
+	{
+	  TYPE_DEPENDENT_P (itype) = 1;
+	  TYPE_DEPENDENT_P_VALID (itype) = 1;
+	}
       SET_TYPE_STRUCTURAL_EQUALITY (itype);
       return itype;
     }