expr.c (store_expr): Don't optimize away load-store pair when either source or…

expr.c (store_expr): Don't optimize away load-store pair when either source or destination have a...

	* expr.c (store_expr): Don't optimize away load-store pair
	when either source or destination have a side effect.

From-SVN: r21732

gcc/ChangeLog

+Fri Aug 14 21:52:53 1998  J"orn Rennecke <amylaar@cygnus.co.uk>
+
+	* expr.c (store_expr): Don't optimize away load-store pair
+	when either source or destination have a side effect.
+
 Fri Aug 14 16:50:10 1998  John Carr  <jfc@mit.edu>
 
 	* genrecog.c (add_to_sequence): Fatal error if the modes of the operands

gcc/expr.c

@@ -3457,7 +3457,10 @@ store_expr (exp, target, want_value)
   /* If value was not generated in the target, store it there.
      Convert the value to TARGET's type first if nec.  */
 
-  if (! rtx_equal_p (temp, target) && TREE_CODE (exp) != ERROR_MARK)
+  if ((! rtx_equal_p (temp, target)
+       || side_effects_p (temp)
+       || side_effects_p (target))
+      && TREE_CODE (exp) != ERROR_MARK)
     {
       target = protect_from_queue (target, 1);
       if (GET_MODE (temp) != GET_MODE (target)