+Wed Nov 18 22:13:00 1998 J"orn Rennecke <amylaar@cygnus.co.uk>
+
+ * expr.c (store_expr): Don't generate load-store pair
+ if TEMP is identical (according to ==) with TARGET.
+
Tue Nov 17 22:25:16 1998 J"orn Rennecke <amylaar@cygnus.co.uk>
* reload1.c (reload_reg_free_for_value_p): When considered reload
/* If value was not generated in the target, store it there.
Convert the value to TARGET's type first if nec. */
+ /* If TEMP and TARGET compare equal according to rtx_equal_p, but
+ one or both of them are volatile memory refs, we have to distinguish
+ two cases:
+ - expand_expr has used TARGET. In this case, we must not generate
+ another copy. This can be detected by TARGET being equal according
+ to == .
+ - expand_expr has not used TARGET - that means that the source just
+ happens to have the same RTX form. Since temp will have been created
+ by expand_expr, it will compare unequal according to == .
+ We must generate a copy in this case, to reach the correct number
+ of volatile memory references. */
if ((! rtx_equal_p (temp, target)
- || side_effects_p (temp)
- || side_effects_p (target))
+ || (temp != target && (side_effects_p (temp)
+ || side_effects_p (target))))
&& TREE_CODE (exp) != ERROR_MARK)
{
target = protect_from_queue (target, 1);