[Bug tree-optimization/41339] Variables can occur multiple times in cfun->local_decls

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41339

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Well, as long as no verification was added (I don't spot any) we can't be sure
if the issue was resolved.  A verification routine can be as simple as the
following (probably overkill for trunk this way, a few verifications like
after we build local decls in gimple-low.c and before RTL expansion in
cfgexpand.c is enough in the end).

Index: gcc/tree-cfg.c
===================================================================
--- gcc/tree-cfg.c      (revision 245240)
+++ gcc/tree-cfg.c      (working copy)
@@ -5093,6 +5121,24 @@ collect_subblocks (hash_set<tree> *block
     }
 }

+/* Verify the functions local_decls.  */
+
+static bool
+verify_local_decls(struct function *fn)
+{
+  /* For the moment verify we don't have any duplicates, see PR41339.  */
+  if (vec_safe_is_empty (fn->local_decls))
+    return false;
+  hash_set <tree> s;
+  for (unsigned i = 0; i < fn->local_decls->length (); ++i)
+    if (s.add ((*fn->local_decls)[i]))
+      {
+       error ("duplicate decls in local-decls");
+       return true;
+      }
+  return false;
+}
+
 /* Verify the GIMPLE statements in the CFG of FN.  */

 DEBUG_FUNCTION void
@@ -5105,6 +5151,8 @@ verify_gimple_in_cfg (struct function *f
   hash_set<void *> visited;
   hash_set<gimple *> visited_stmts;

+  err |= verify_local_decls (fn);
+
   /* Collect all BLOCKs referenced by the BLOCK tree of FN.  */
   hash_set<tree> blocks;
   if (DECL_INITIAL (fn->decl))