Remove obsolete comment

[Eric Botcazou]

The first part is obsolete since r91570 at least, for the second part about 
MEM_KEEP_ALIAS_SET_P it's more recent.

Tested on x86_64-suse-linux, applied on the mainline.


2013-09-26  Eric Botcazou  <ebotca...@adacore.com>

        * expr.c (expand_assignment): Remove obsolete comment.


-- 
Eric Botcazou
Index: expr.c
===================================================================
--- expr.c	(revision 202912)
+++ expr.c	(working copy)
@@ -4836,11 +4836,7 @@ expand_assignment (tree to, tree from, b
 	      /* If the field is at offset zero, we could have been given the
 		 DECL_RTX of the parent struct.  Don't munge it.  */
 	      to_rtx = shallow_copy_rtx (to_rtx);
-
 	      set_mem_attributes_minus_bitpos (to_rtx, to, 0, bitpos);
-
-	      /* Deal with volatile and readonly fields.  The former is only
-		 done for MEM.  Also set MEM_KEEP_ALIAS_SET_P if needed.  */
 	      if (volatilep)
 		MEM_VOLATILE_P (to_rtx) = 1;
 	    }