diff --git a/src/dfa.c b/src/dfa.c
index 6ab4e05..5e6120d 100644
--- a/src/dfa.c
+++ b/src/dfa.c
@@ -1094,7 +1094,6 @@ parse_bracket_exp (void)
               work_mbc->range_ends[work_mbc->nranges++] =
                 case_fold ? towlower (wc2) : (wchar_t) wc2;
 
-#ifndef GREP
               if (case_fold && (iswalpha (wc) || iswalpha (wc2)))
                 {
                   REALLOC_IF_NECESSARY (work_mbc->range_sts,
@@ -1104,7 +1103,6 @@ parse_bracket_exp (void)
                                         range_ends_al, work_mbc->nranges + 1);
                   work_mbc->range_ends[work_mbc->nranges++] = towupper (wc2);
                 }
-#endif
             }
           else
             {
@@ -1156,11 +1154,7 @@ parse_bracket_exp (void)
                                     work_mbc->nchars + 1);
               work_mbc->chars[work_mbc->nchars++] = wc;
             }
-#ifdef GREP
-          continue;
-#else
           wc = towupper (wc);
-#endif
         }
       if (!setbit_wc (wc, ccl))
         {
@@ -1754,13 +1748,11 @@ atom (void)
   else if (MBS_SUPPORT && tok == WCHAR)
     {
       addtok_wc (case_fold ? towlower (wctok) : wctok);
-#ifndef GREP
       if (case_fold && iswalpha (wctok))
         {
           addtok_wc (towupper (wctok));
           addtok (OR);
         }
-#endif
 
       tok = lex ();
     }
diff --git a/src/dfasearch.c b/src/dfasearch.c
index 46581ff..04f26e4 100644
--- a/src/dfasearch.c
+++ b/src/dfasearch.c
@@ -95,6 +95,11 @@ kwsmusts (void)
   struct dfamust const *dm;
   char const *err;
 
+  /* Don't use kwsearch because case-insensitive matching is
+     expensive in multi-byte locales with it. */
+  if (MB_CUR_MAX > 1 && match_icase)
+    return;
+
   dm = dfamusts (dfa);
   if (dm)
     {
@@ -220,19 +225,6 @@ EGexecute (char const *buf, size_t size, size_t *match_size,
   size_t i, ret_val;
   mb_len_map_t *map = NULL;
 
-  if (MB_CUR_MAX > 1)
-    {
-      if (match_icase)
-        {
-          /* mbtolower adds a NUL byte at the end.  That will provide
-             space for the sentinel byte dfaexec may add.  */
-          char *case_buf = mbtolower (buf, &size, &map);
-          if (start_ptr)
-            start_ptr = case_buf + (start_ptr - buf);
-          buf = case_buf;
-        }
-    }
-
   mb_start = buf;
   buflim = buf + size;