------- Comment #3 from ubizjak at gmail dot com 2009-01-17 18:40 -------
(In reply to comment #2)
> That code is ancient, and wrong from day 1 if your analysis is correct :-)
Hm, no. The code is correct, but applies only to symbols involving ANDs.
We need somehing like this code also for the case when one of operands is
non-symbol and the other involves AND. I'm testing following patch:
--cut here--
Index: alias.c
===================================================================
--- alias.c (revision 143461)
+++ alias.c (working copy)
@@ -1543,6 +1543,20 @@ base_alias_check (rtx x, rtx y, enum mac
return 0;
}
+ if (GET_CODE (x_base) == ADDRESS || GET_CODE (y_base) == ADDRESS)
+ {
+ if (GET_CODE (x) == AND && GET_CODE (y) == AND)
+ return 1;
+ if (GET_CODE (x) == AND
+ && (GET_CODE (XEXP (x, 1)) != CONST_INT
+ || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1))))
+ return 1;
+ if (GET_CODE (y) == AND
+ && (GET_CODE (XEXP (y, 1)) != CONST_INT
+ || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1))))
+ return 1;
+ }
+
/* If one address is a stack reference there can be no alias:
--cut here--
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38879
