extend.texi (Arrays and pointers implementation): Discourage relying on sign-extension of pointers.

        * doc/extend.texi (Arrays and pointers implementation): Discourage
        relying on sign-extension of pointers.

From-SVN: r44805

gcc/ChangeLog

+2001-08-11  Richard Henderson  <rth@redhat.com>
+
+	* doc/extend.texi (Arrays and pointers implementation): Discourage
+	relying on sign-extension of pointers.
+
 2001-08-11  H.J. Lu <hjl@gnu.org>
 
 	* config/mips/linux.h (EXTRA_SECTIONS): Remove in_ctors and

gcc/doc/extend.texi

@@ -202,7 +202,9 @@ IEC 60559 conformant implementation (F.9).}
 vice versa (6.3.2.3).}
 
 A cast from pointer to integer discards most-significant bits if the
-pointer representation is larger than the integer type, sign-extends
+pointer representation is larger than the integer type,
+sign-extends@footnote{Future versions of GCC may zero-extend, or use
+a target-defined @code{ptr_extend} pattern.  Do not rely on sign extension.}
 if the pointer representation is smaller than the integer type, otherwise
 the bits are unchanged.
 @c ??? We've always claimed that pointers were unsigned entities.