Fix a terrible slowdown in large fully fontified buffers.

 src/xdisp.c <cached_disp_pos, cached_disp_buffer, cached_disp_modiff>:
 Cache for last found display string position.
 (compute_display_string_pos): Return the cached position if asked
 about the same buffer.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 21c394480bf..0114495838f 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2011-07-16  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c <cached_disp_pos, cached_disp_buffer, cached_disp_modiff>:
+        Cache for last found display string position.
+        (compute_display_string_pos): Return the cached position if asked
+        about the same buffer.
+
 2011-07-14  Eli Zaretskii  <eliz@gnu.org>
 
         * bidi.c (bidi_cache_fetch_state, bidi_cache_search)