(back_comment): Move the find_defun_start call

out of the scan_sexps_forward call.
No need to call find_defun_start
if we found the defun start in the initial scan.

1 files changed, 19 insertions, 4 deletions

diff --git a/src/syntax.c b/src/syntax.c
index b3ec37f3b29..9f0495401dc 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -407,9 +407,15 @@ back_comment (from, from_byte, stop, comstyle, charpos_ptr, bytepos_ptr)
   int comment_end = from;
   int comment_end_byte = from_byte;
   int comstart_pos = 0;
-  int comstart_parity = 0;
   int comstart_byte;
+  /* Value that PARITY had, when we reached the position
+     in COMSTART_POS.  */
+  int comstart_parity = 0;
   int scanstart = from - 1;
+  /* Place where the containing defun starts,
+     or 0 if we didn't come across it yet.  */
+  int defun_start = 0;
+  int defun_start_byte = 0;
   register enum syntaxcode code;
   int c;
 
@@ -497,7 +503,11 @@ back_comment (from, from_byte, stop, comstyle, charpos_ptr, bytepos_ptr)
           && (from == stop
               || (temp_byte = dec_bytepos (from_byte),
                   FETCH_CHAR (temp_byte) == '\n')))
-        break;
+        {
+          defun_start = from;
+          defun_start_byte = from_byte;
+          break;
+        }
     }
 
   if (comstart_pos == 0)
@@ -525,9 +535,14 @@ back_comment (from, from_byte, stop, comstyle, charpos_ptr, bytepos_ptr)
          to the one in question; this records where we
          last passed a comment starter.  */
       struct lisp_parse_state state;
+      /* If we did not already find the defun start, find it now.  */
+      if (defun_start == 0)
+        {
+          defun_start = find_defun_start (comment_end, comment_end_byte);
+          defun_start_byte = find_start_value_byte;
+        }
       scan_sexps_forward (&state,
-                          find_defun_start (comment_end, comment_end_byte),
-                          find_start_value_byte,
+                          defun_start, defun_start_byte,
                           comment_end - 1, -10000, 0, Qnil, 0);
       if (state.incomment)
         {