* marker.c (set_marker_internal): If desired position is passed

as a marker, avoid call to buf_charpos_to_bytepos.
* window.c (Fset_window_point): Omit redundant type checking.
(Fset_window_start): Likewise.  Format comment.
(window_scroll_pixel_based): Use set_marker_restricted_both
with character and byte positions obtained from an iterator.
(Fset_window_configuration): Use set_marker_restricted_both.
* xdisp.c (message_dolog): Likewise.

src/ChangeLog

+2013-02-11  Dmitry Antipov  <dmantipov@yandex.ru>
+
+	* marker.c (set_marker_internal): If desired position is passed
+	as a marker, avoid call to buf_charpos_to_bytepos.
+	* window.c (Fset_window_point): Omit redundant type checking.
+	(Fset_window_start): Likewise.  Format comment.
+	(window_scroll_pixel_based): Use set_marker_restricted_both
+	with character and byte positions obtained from an iterator.
+	(Fset_window_configuration): Use set_marker_restricted_both.
+	* xdisp.c (message_dolog): Likewise.
+
 2013-02-10  Eli Zaretskii  <eliz@gnu.org>
 
 	* xdisp.c (move_it_vertically_backward, move_it_by_lines): When

src/marker.c

@@ -499,11 +499,29 @@ set_marker_internal (Lisp_Object marker, Lisp_Object position,
     {
       register ptrdiff_t charpos, bytepos;
 
-      CHECK_NUMBER_COERCE_MARKER (position);
-      charpos = clip_to_bounds (restricted ? BUF_BEGV (b) : BUF_BEG (b),
-                               XINT (position),
-                               restricted ? BUF_ZV (b) : BUF_Z (b));
-      bytepos = buf_charpos_to_bytepos (b, charpos);
+      /* Do not use CHECK_NUMBER_COERCE_MARKER because we
+	 don't want to call buf_charpos_to_bytepos if POSTION
+	 is a marker and so we know the bytepos already.  */
+      if (INTEGERP (position))
+	charpos = XINT (position), bytepos = -1;
+      else if (MARKERP (position))
+	{
+	  charpos = XMARKER (position)->charpos;
+	  bytepos = XMARKER (position)->bytepos;
+	}
+      else
+	wrong_type_argument (Qinteger_or_marker_p, position);
+
+      charpos = clip_to_bounds
+	(restricted ? BUF_BEGV (b) : BUF_BEG (b), charpos,
+	 restricted ? BUF_ZV (b) : BUF_Z (b));
+      if (bytepos == -1)
+	bytepos = buf_charpos_to_bytepos (b, charpos);
+      else
+	bytepos = clip_to_bounds
+	  (restricted ? BUF_BEGV_BYTE (b) : BUF_BEG_BYTE (b),
+	   bytepos, restricted ? BUF_ZV_BYTE (b) : BUF_Z_BYTE (b));
+
       attach_marker (m, b, charpos, bytepos);
     }
   return marker;

src/window.c

@@ -1544,7 +1544,7 @@ Return POS.  */)
 {
   register struct window *w = decode_live_window (window);
 
-  CHECK_NUMBER_COERCE_MARKER (pos);
+  /* Type of POS is checked by Fgoto_char or set_marker_restricted ...  */
 
   if (w == XWINDOW (selected_window))
     {
@@ -1554,6 +1554,8 @@ Return POS.  */)
 	{
 	  struct buffer *old_buffer = current_buffer;
 
+	  /* ... but here we want to catch type error before buffer change.  */
+	  CHECK_NUMBER_COERCE_MARKER (pos);
 	  set_buffer_internal (XBUFFER (w->buffer));
 	  Fgoto_char (pos);
 	  set_buffer_internal (old_buffer);
@@ -1579,9 +1581,8 @@ overriding motion of point in order to display at this exact start.  */)
 {
   register struct window *w = decode_live_window (window);
 
-  CHECK_NUMBER_COERCE_MARKER (pos);
   set_marker_restricted (w->start, pos, w->buffer);
-  /* this is not right, but much easier than doing what is right. */
+  /* This is not right, but much easier than doing what is right.  */
   w->start_at_line_beg = 0;
   if (NILP (noforce))
     w->force_start = 1;
@@ -4615,8 +4616,8 @@ window_scroll_pixel_based (Lisp_Object window, int n, int whole, int noerror)
 	}
 
       /* Set the window start, and set up the window for redisplay.  */
-      set_marker_restricted (w->start, make_number (pos),
-			     w->buffer);
+      set_marker_restricted_both (w->start, w->buffer, IT_CHARPOS (it),
+				  IT_BYTEPOS (it));
       bytepos = marker_byte_position (w->start);
       w->start_at_line_beg = (pos == BEGV || FETCH_BYTE (bytepos - 1) == '\n');
       w->update_mode_line = 1;
@@ -5795,8 +5796,7 @@ the return value is nil.  Otherwise the value is t.  */)
 	     {
 	       /* Set window markers at start of visible range.  */
 	       if (XMARKER (w->start)->buffer == 0)
-		 set_marker_restricted (w->start, make_number (0),
-					w->buffer);
+		 set_marker_restricted_both (w->start, w->buffer, 0, 0);
 	       if (XMARKER (w->pointm)->buffer == 0)
 		 set_marker_restricted_both
 		   (w->pointm, w->buffer,
@@ -5814,10 +5814,8 @@ the return value is nil.  Otherwise the value is t.  */)
 	      wset_buffer (w, other_buffer_safely (Fcurrent_buffer ()));
 	      /* This will set the markers to beginning of visible
 		 range.  */
-	      set_marker_restricted (w->start,
-				     make_number (0), w->buffer);
-	      set_marker_restricted (w->pointm,
-				     make_number (0), w->buffer);
+	      set_marker_restricted_both (w->start, w->buffer, 0, 0);
+	      set_marker_restricted_both (w->pointm, w->buffer, 0, 0);
 	      w->start_at_line_beg = 1;
 	      if (!NILP (w->dedicated))
 		/* Record this window as dead.  */

src/xdisp.c

@@ -9396,11 +9396,11 @@ message_dolog (const char *m, ptrdiff_t nbytes, int nlflag, int multibyte)
       bset_undo_list (current_buffer, Qt);
 
       oldpoint = message_dolog_marker1;
-      set_marker_restricted (oldpoint, make_number (PT), Qnil);
+      set_marker_restricted_both (oldpoint, Qnil, PT, PT_BYTE);
       oldbegv = message_dolog_marker2;
-      set_marker_restricted (oldbegv, make_number (BEGV), Qnil);
+      set_marker_restricted_both (oldbegv, Qnil, BEGV, BEGV_BYTE);
       oldzv = message_dolog_marker3;
-      set_marker_restricted (oldzv, make_number (ZV), Qnil);
+      set_marker_restricted_both (oldzv, Qnil, ZV, ZV_BYTE);
       GCPRO1 (old_deactivate_mark);
 
       if (PT == Z)