Reword a comment in varpool_node::ctor_useable_for_folding_p.

	* varpool.c (ctor_useable_for_folding_p): Fix grammar.

gcc/ChangeLog

+2019-01-18  Gerald Pfeifer  <gerald@pfeifer.com>
+
+	* varpool.c (ctor_useable_for_folding_p): Fix grammar.
+
 2020-01-18  Iain Sandoe  <iain@sandoe.co.uk>
 
 	* Makefile.in: Add coroutine-passes.o.

gcc/varpool.c

@@ -352,9 +352,10 @@ varpool_node::ctor_useable_for_folding_p (void)
       return DECL_INITIAL (real_node->decl) != NULL;
     }
 
-  /* Alias of readonly variable is also readonly, since the variable is stored
-     in readonly memory.  We also accept readonly aliases of non-readonly
-     locations assuming that user knows what he is asking for.  */
+  /* An alias of a read-only variable is also read-only, since the variable
+     is stored in read-only memory.  We also accept read-only aliases of
+     non-read-only locations assuming that the user knows what he is asking
+     for.  */
   if (!TREE_READONLY (decl) && !TREE_READONLY (real_node->decl))
     return false;