[tuples] If you need to re-enable -O2

[Diego Novillo]

I forgot to add in my earlier patch that if you are working on
converting a pass and need to enable -O2 in your local tree, you can
apply this reversal patch to opts.c:

Index: opts.c
===================================================================
--- opts.c      (revision 132051)
+++ opts.c      (working copy)
@@ -775,16 +775,6 @@ decode_options (unsigned int argc, const
        }
     }

-  /* FIXME tuples.  Force optimization level to 0 until alias analysis
-     and complex lowering at O1+ is fully enabled.  */
-  if (flag_gimple_conversion == 0)
-    {
-      optimize = 0;
-      optimize_size = 0;
-    }
-  else
-    gimple_unreachable ();
-
   if (!optimize)
     {
       flag_merge_constants = 0;