Fix bug #11199 with killing a line at EOB that was bidi-reordered.

 src/xdisp.c (find_last_unchanged_at_beg_row): Don't consider a row
 "unchanged" if its end.pos is beyond ZV.

src/ChangeLog

+2012-04-09  Eli Zaretskii  <eliz@gnu.org>
+
+	* xdisp.c (find_last_unchanged_at_beg_row): Don't consider a row
+	"unchanged" if its end.pos is beyond ZV.  (Bug#11199)
+
 2012-04-09  Jan Djärv  <jan.h.d@swipnet.se>
 
 	* nsterm.m (constrainFrameRect): Always constrain when there is only

src/xdisp.c

@@ -16602,7 +16602,15 @@ find_last_unchanged_at_beg_row (struct window *w)
 	     continued.  */
 	  && !(MATRIX_ROW_END_CHARPOS (row) == first_changed_pos
 	       && (row->continued_p
-		   || row->exact_window_width_line_p)))
+		   || row->exact_window_width_line_p))
+	  /* If ROW->end is beyond ZV, then ROW->end is outdated and
+	     needs to be recomputed, so don't consider this row as
+	     unchanged.  This happens when the last line was
+	     bidi-reordered and was killed immediately before this
+	     redisplay cycle.  In that case, ROW->end stores the
+	     buffer position of the first visual-order character of
+	     the next row, which is now beyond ZV.  */
+	  && CHARPOS (row->end.pos) <= ZV)
 	row_found = row;
       /* Stop if last visible row.  */