(Fbackward_prefix_chars): Set point properly while scanning.

(scan_sexps_forward): Make INC_FROM do UPDATE_SYNTAX_TABLE_FORWARD.
Delete the explicit calls to UPDATE_SYNTAX_TABLE_FORWARD.
Also set prev_from_syntax (new local var).  Test that in the loop,
instead of fetching syntax of the previous char.

1 files changed, 26 insertions, 17 deletions

diff --git a/src/syntax.c b/src/syntax.c
index 4ac1c8d1b83..02357671608 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -2174,12 +2174,16 @@ This includes chars with \"quote\" or \"prefix\" syntax (' or p).")
 
   DEC_BOTH (pos, pos_byte);
 
-  while (pos + 1 > beg && !char_quoted (pos, pos_byte)
+  while (!char_quoted (pos, pos_byte)
          /* Previous statement updates syntax table.  */
          && ((c = FETCH_CHAR (pos_byte), SYNTAX (c) == Squote)
              || SYNTAX_PREFIX (c)))
     {
-      DEC_BOTH (pos, pos_byte);
+      opoint = pos;
+      opoint_byte = pos_byte;
+
+      if (pos + 1 > beg)
+        DEC_BOTH (pos, pos_byte);
     }
 
   SET_PT_BOTH (opoint, opoint_byte);
@@ -2220,6 +2224,7 @@ scan_sexps_forward (stateptr, from, from_byte, end, targetdepth,
   Lisp_Object tem;
   int prev_from;                /* Keep one character before FROM.  */
   int prev_from_byte;
+  int prev_from_syntax;
   int boundary_stop = commentstop == -1;
   int nofence;
 
@@ -2232,14 +2237,15 @@ scan_sexps_forward (stateptr, from, from_byte, end, targetdepth,
 #define INC_FROM                                \
 do { prev_from = from;                          \
      prev_from_byte = from_byte;                \
+     prev_from_syntax                           \
+       = SYNTAX_WITH_FLAGS (FETCH_CHAR (prev_from_byte)); \
      INC_BOTH (from, from_byte);                \
+     UPDATE_SYNTAX_TABLE_FORWARD (from);        \
   } while (0)
 
   immediate_quit = 1;
   QUIT;
 
-  SETUP_SYNTAX_TABLE (from, 1);
-
   if (NILP (oldstate))
     {
       depth = 0;
@@ -2302,11 +2308,15 @@ do { prev_from = from;				\
     }
   if (start_quoted) goto startquoted;
 
+
+  SETUP_SYNTAX_TABLE (prev_from, 1);
+  prev_from_syntax = SYNTAX_WITH_FLAGS (FETCH_CHAR (prev_from_byte));
+  UPDATE_SYNTAX_TABLE_FORWARD (from);
+
   while (from < end)
     {
-      UPDATE_SYNTAX_TABLE_FORWARD (from);
-      code = SYNTAX (FETCH_CHAR (from_byte));
       INC_FROM;
+      code = prev_from_syntax & 0xff;
 
       if (code == Scomment)
         state.comstr_start = prev_from;
@@ -2319,13 +2329,14 @@ do { prev_from = from;				\
                              ? ST_COMMENT_STYLE 
                              : SYNTAX_COMMENT_STYLE (FETCH_CHAR (from_byte)));
           state.comstr_start = prev_from;
-          if (code != Scomment_fence) INC_FROM;
+          if (code != Scomment_fence)
+            INC_FROM;
           code = Scomment;
         }
      else if (from < end)
-        if (SYNTAX_COMSTART_FIRST (FETCH_CHAR (prev_from_byte)))
+        if (SYNTAX_FLAGS_COMSTART_FIRST (prev_from_syntax))
           if (SYNTAX_COMSTART_SECOND (FETCH_CHAR (from_byte)))
-            /* Duplicate code to avoid a very complex if-expression
+            /* Duplicate code to avoid a complex if-expression
                which causes trouble for the SGI compiler.  */
             {
               /* Record the comment style we have entered so that only
@@ -2335,11 +2346,12 @@ do { prev_from = from;				\
                                  ? ST_COMMENT_STYLE 
                                  : SYNTAX_COMMENT_STYLE (FETCH_CHAR (from_byte)));
               state.comstr_start = prev_from;
-              if (code != Scomment_fence) INC_FROM;
+              if (code != Scomment_fence)
+                INC_FROM;
               code = Scomment;
             }
 
-      if (SYNTAX_PREFIX (FETCH_CHAR (prev_from_byte)))
+      if (SYNTAX_FLAGS_PREFIX (prev_from_syntax))
         continue;
       switch (SWITCH_ENUM_CAST (code))
         {
@@ -2359,7 +2371,6 @@ do { prev_from = from;				\
         symstarted:
           while (from < end)
             {
-              UPDATE_SYNTAX_TABLE_FORWARD (from);
               switch (SWITCH_ENUM_CAST (SYNTAX (FETCH_CHAR (from_byte))))
                 {
                 case Scharquote:
@@ -2387,7 +2398,6 @@ do { prev_from = from;				\
             {
               /* Enter the loop in the middle so that we find
                  a 2-char comment ender if we start in the middle of it.  */
-              prev = FETCH_CHAR (prev_from_byte);
               goto startincomment_1;
             }
           /* At beginning of buffer, enter the loop the ordinary way.  */
@@ -2401,7 +2411,6 @@ do { prev_from = from;				\
           while (1)
             {
               if (from == end) goto done;
-              UPDATE_SYNTAX_TABLE_FORWARD (from);
               prev = FETCH_CHAR (from_byte);
               if (SYNTAX (prev) == Sendcomment
                   && SYNTAX_COMMENT_STYLE (prev) == state.comstyle)
@@ -2414,9 +2423,10 @@ do { prev_from = from;				\
                 break;
               INC_FROM;
             startincomment_1:
-              if (from < end && SYNTAX_COMEND_FIRST (prev)
+              if (from < end && SYNTAX_FLAGS_COMEND_FIRST (prev_from_syntax)
                   && SYNTAX_COMEND_SECOND (FETCH_CHAR (from_byte))
-                  && SYNTAX_COMMENT_STYLE (prev) == state.comstyle)
+                  && (SYNTAX_FLAGS_COMMENT_STYLE (prev_from_syntax)
+                      == state.comstyle))
                 /* Only terminate the comment section if the end-comment
                    sequence of the same style as the start sequence has
                    been encountered.  */
@@ -2470,7 +2480,6 @@ do { prev_from = from;				\
                 if (from >= end) goto done;
                 c = FETCH_CHAR (from_byte);
                 if (nofence && c == state.instring) break;
-                UPDATE_SYNTAX_TABLE_FORWARD (from);
                 switch (SWITCH_ENUM_CAST (SYNTAX (c)))
                   {
                   case Sstring_fence: