[match-and-simplify] error checking on user defined oper in for

[Prathamesh Kulkarni]

Currently this is accepted:
(for plus (mult div)
  ...)
which is incorrect. This patch puts more error-checks on the user-defined
operator in for-pattern.

* genmatch.c
  (insert_operator): New function.
  (parse_for): Call insert_operator.

Thanks,
Prathamesh

Index: gcc/genmatch.c
===================================================================
--- gcc/genmatch.c	(revision 216673)
+++ gcc/genmatch.c	(working copy)
@@ -349,8 +349,41 @@
   return 0;
 }
 
+id_base *
+insert_operator (id_base *op)
+{
+  id_base **orig_slot;
+  id_base **slot = orig_slot = operators->find_slot_with_hash (op, op->hashval, INSERT);
+  if (*slot)
+    return 0;
 
+  char *id2 = xstrdup (op->id);
+  for (unsigned i = 0; i < strlen (id2); ++i)
+    id2[i] = TOUPPER (id2[i]);
 
+  id_base tem (id_base::CODE, id2); 
+  slot = operators->find_slot_with_hash (&tem, tem.hashval, INSERT);
+  if (*slot)
+    {
+      free (id2);
+      return 0;
+    }
+
+  /* Try _EXPR appended */
+  id2 = (char *)xrealloc (id2, strlen (id2) + sizeof ("_EXPR") + 1);
+  strcat (id2, "_EXPR");
+  id_base tem2 (id_base::CODE, id2); 
+  slot = operators->find_slot_with_hash (&tem2, tem2.hashval, INSERT);
+
+  if (*slot)
+    {
+      free (id2);
+      return 0;
+    }
+
+  *orig_slot = op;
+  return *orig_slot;
+}
 /* The AST produced by parsing of the pattern definitions.  */
 
 struct dt_operand;
@@ -2920,10 +2953,8 @@
       /* Insert the user defined operators into the operator hash.  */
       const char *id = get_ident ();
       user_id *op = new user_id (id);
-      id_base **slot = operators->find_slot_with_hash (op, op->hashval, INSERT);
-      if (*slot)
-	fatal_at (token, "operator already defined");
-      *slot = op;
+      if (insert_operator (op) == 0)
+	fatal_at (token, "operator '%s' already defined", id);
       user_ids.safe_push (op);
 
       eat_token (CPP_OPEN_PAREN);