[Bug lto/60720] clisp fails to build with -flto: internal compiler error: tree check: expected array_type, have record_type in array_ref_low_bound, at expr.c:6941

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60720

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
We miss to wrap uses of non-automatic vars inside MEM_REFs for global
initializers
(we do that for the IL already).

Doing this raises the question whether we shouldn't simply special-case
global var references and stream a type which each reference, materializing
a MEM_REF only when necessary (not sure if we know that at the point we are
materializing the initializer).

Anyway, short-term fix:

Index: gcc/lto-streamer-out.c
===================================================================
--- gcc/lto-streamer-out.c      (revision 208955)
+++ gcc/lto-streamer-out.c      (working copy)
@@ -313,6 +313,27 @@ lto_is_streamable (tree expr)
 }


+/* Wrap symbol references in *TP inside a type-preserving MEM_REF.  */
+
+static tree
+wrap_refs (tree *tp, int *ws, void *)
+{
+  tree t = *tp;
+  if (TREE_CODE (t) == VAR_DECL)
+    {
+      tree ptrtype = build_pointer_type (TREE_TYPE (t));
+      *tp = build2 (MEM_REF, TREE_TYPE (t),
+                   build1 (ADDR_EXPR, ptrtype, t),
+                   build_int_cst (ptrtype, 0));
+      *ws = 0;
+    }
+  else if (TREE_CODE (t) == CONSTRUCTOR)
+    ;
+  else if (!EXPR_P (t))
+    *ws = 0;
+  return NULL_TREE;
+}
+
 /* For EXPR lookup and return what we want to stream to OB as DECL_INITIAL. 
*/

 static tree
@@ -340,6 +361,14 @@ get_symbol_initial_value (struct output_
        initial = error_mark_node;
     }

+  /* Wrap all symbol references inside the initializer in a MEM_REF
+     to preserve the type at the use even in case the symbol is
+     prevailed by one with a different type.  We can safely skip this
+     during WPA.  */
+  if (!in_lto_p
+      && initial && initial != error_mark_node)
+    walk_tree (&initial, wrap_refs, NULL, NULL);
+
   return initial;
 }