2 files changed, 17 insertions, 15 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 27c2b7246af..1ac89ec8561 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2009-11-22  Andreas Schwab  <schwab@linux-m68k.org>
+
+        * search.c (simple_search): Avoid CHAR_TO_BYTE in inner loop when
+        searching backwards through multibyte buffer.
+
 2009-11-21  Jan Djärv  <jan.h.d@swipnet.se>
 
         * xterm.c: #include xgselect.h.
diff --git a/src/search.c b/src/search.c
index fd45d316a46..abbad764c3c 100644
--- a/src/search.c
+++ b/src/search.c
@@ -1609,39 +1609,36 @@ simple_search (n, pat, len, len_byte, trt, pos, pos_byte, lim, lim_byte)
         while (1)
           {
             /* Try matching at position POS.  */
-            EMACS_INT this_pos = pos - len;
-            EMACS_INT this_pos_byte;
+            EMACS_INT this_pos = pos;
+            EMACS_INT this_pos_byte = pos_byte;
             int this_len = len;
-            unsigned char *p = pat;
+            unsigned char *p = pat + len_byte;
 
-            if (this_pos < lim || (pos_byte - len_byte) < lim_byte)
+            if (this_pos - len < lim || (pos_byte - len_byte) < lim_byte)
               goto stop;
-            this_pos_byte = CHAR_TO_BYTE (this_pos);
-            match_byte = pos_byte - this_pos_byte;
 
             while (this_len > 0)
               {
-                int charlen, buf_charlen;
+                int charlen;
                 int pat_ch, buf_ch;
 
-                pat_ch = STRING_CHAR_AND_LENGTH (p, charlen);
-                buf_ch = STRING_CHAR_AND_LENGTH (BYTE_POS_ADDR (this_pos_byte),
-                                                 buf_charlen);
+                DEC_BOTH (this_pos, this_pos_byte);
+                PREV_CHAR_BOUNDARY (p, pat);
+                pat_ch = STRING_CHAR (p);
+                buf_ch = STRING_CHAR (BYTE_POS_ADDR (this_pos_byte));
                 TRANSLATE (buf_ch, trt, buf_ch);
 
                 if (buf_ch != pat_ch)
                   break;
 
                 this_len--;
-                p += charlen;
-                this_pos_byte += buf_charlen;
-                this_pos++;
               }
 
             if (this_len == 0)
               {
-                pos -= len;
-                pos_byte -= match_byte;
+                match_byte = pos_byte - this_pos_byte;
+                pos = this_pos;
+                pos_byte = this_pos_byte;
                 break;
               }