1 files changed, 11 insertions, 18 deletions

diff --git a/src/window.c b/src/window.c
index d38f4c10671..906cfe6ba9d 100644
--- a/src/window.c
+++ b/src/window.c
@@ -287,6 +287,8 @@ adjust_window_count (struct window *w, int arg)
 	b = b->base_buffer;
       b->window_count += arg;
       eassert (b->window_count >= 0);
+      /* Catch redisplay's attention.  */
+      w->window_end_valid = 0;
     }
 }
 
@@ -1490,17 +1492,8 @@ if it isn't already recorded.  */)
   CHECK_BUFFER (buf);
   b = XBUFFER (buf);
 
-#if 0 /* This change broke some things.  We should make it later.  */
-  /* If we don't know the end position, return nil.
-     The user can compute it with vertical-motion if he wants to.
-     It would be nicer to do it automatically,
-     but that's so slow that it would probably bother people.  */
-  if (NILP (w->window_end_valid))
-    return Qnil;
-#endif
-
   if (! NILP (update)
-      && (windows_or_buffers_changed || NILP (w->window_end_valid))
+      && (windows_or_buffers_changed || !w->window_end_valid)
       && !noninteractive)
     {
       struct text_pos startp;
@@ -1707,7 +1700,7 @@ Return nil if window display is not up-to-date.  In that case, use
   b = XBUFFER (w->buffer);
 
   /* Fail if current matrix is not up-to-date.  */
-  if (NILP (w->window_end_valid)
+  if (!w->window_end_valid
       || current_buffer->clip_changed
       || current_buffer->prevent_redisplay_optimizations_p
       || w->last_modified < BUF_MODIFF (b)
@@ -2039,7 +2032,7 @@ replace_window (Lisp_Object old, Lisp_Object new, int setflag)
       n->pseudo_window_p = 0;
       wset_window_end_vpos (n, make_number (0));
       wset_window_end_pos (n, make_number (0));
-      wset_window_end_valid (n, Qnil);
+      n->window_end_valid = 0;
       n->frozen_window_start_p = 0;
     }
 
@@ -2974,7 +2967,7 @@ window-start value is reasonable when this function is called.  */)
 	  pos = *vmotion (startpos, -top, w);
 
 	  set_marker_both (w->start, w->buffer, pos.bufpos, pos.bytepos);
-	  wset_window_end_valid (w, Qnil);
+	  w->window_end_valid = 0;
 	  w->start_at_line_beg = (pos.bytepos == BEGV_BYTE
 				    || FETCH_BYTE (pos.bytepos - 1) == '\n');
 	  /* We need to do this, so that the window-scroll-functions
@@ -3190,7 +3183,7 @@ set_window_buffer (Lisp_Object window, Lisp_Object buffer, int run_hooks_p, int
   wset_window_end_pos (w, make_number (0));
   wset_window_end_vpos (w, make_number (0));
   memset (&w->last_cursor, 0, sizeof w->last_cursor);
-  wset_window_end_valid (w, Qnil);
+
   if (!(keep_margins_p && samebuf))
     { /* If we're not actually changing the buffer, don't reset hscroll and
 	 vscroll.  This case happens for example when called from
@@ -3959,7 +3952,7 @@ set correctly.  See the code of `split-window' for how this is done.  */)
       wset_next (o, new);
     }
 
-  wset_window_end_valid (n, Qnil);
+  n->window_end_valid = 0;
   memset (&n->last_cursor, 0, sizeof n->last_cursor);
 
   /* Get special geometry settings from reference window.  */
@@ -5372,7 +5365,7 @@ and redisplay normally--don't erase and redraw the frame.  */)
 
   /* Set the new window start.  */
   set_marker_both (w->start, w->buffer, charpos, bytepos);
-  wset_window_end_valid (w, Qnil);
+  w->window_end_valid = 0;
 
   w->optional_new_start = 1;
 
@@ -6323,7 +6316,7 @@ display marginal areas and the text area.  */)
       adjust_window_margins (w);
 
       clear_glyph_matrix (w->current_matrix);
-      wset_window_end_valid (w, Qnil);
+      w->window_end_valid = 0;
 
       ++windows_or_buffers_changed;
       adjust_glyphs (XFRAME (WINDOW_FRAME (w)));
@@ -6393,7 +6386,7 @@ Fourth parameter HORIZONTAL-TYPE is currently unused.  */)
       adjust_window_margins (w);
 
       clear_glyph_matrix (w->current_matrix);
-      wset_window_end_valid (w, Qnil);
+      w->window_end_valid = 0;
 
       ++windows_or_buffers_changed;
       adjust_glyphs (XFRAME (WINDOW_FRAME (w)));