[patch] Document restriction of scalar_storage_order

[Eric Botcazou]

Tested on x86_64-suse-linux, OK for the mainline?


2016-01-21  Eric Botcazou  <ebotca...@adacore.com>

        * doc/extend.texi (scalar_storage_order type attribute): Document
        restriction on type punning and aliasing.

-- 
Eric Botcazou
Index: doc/extend.texi
===================================================================
--- doc/extend.texi	(revision 232465)
+++ doc/extend.texi	(working copy)
@@ -6512,6 +6512,10 @@ is taken, so storing indirectly through
 The second case is nevertheless allowed to be able to perform a block copy
 from or to the array.
 
+Moreover, the use of type punning or aliasing to toggle the storage order
+is not supported; that is to say, a given scalar object cannot be accessed
+through distinct types that assign a different storage order to it.
+
 @item transparent_union
 @cindex @code{transparent_union} type attribute