Simplify and cleanup character conversion stuff.

* lisp.h (multibyte_char_to_unibyte, multibyte_char_to_unibyte_safe):
Remove prototypes.
* character.c (multibyte_char_to_unibyte)
(multibyte_char_to_unibyte_safe): Remove; no longer used.
* character.h (make_char): Remove; unused.
(CHAR_TO_BYTE8, CHAR_TO_BYTE_SAFE): Simplify.
(ASCII_BYTE_P): Remove; ASCII_CHAR_P does the same thing.
* buffer.c, charset.c, charset.h, cmds.c, coding.c, editfns.c:
* fileio.c, indent.c, insdel.c, keyboard.c, lread.c, print.c:
* search.c, term.c, xdisp.c, xterm.c: Related users changed.

20 files changed, 68 insertions, 98 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index fe3a570ee3b..0fc0401265c 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,17 @@
+2014-06-23  Dmitry Antipov  <dmantipov@yandex.ru>
+
+        Simplify and cleanup character conversion stuff.
+        * lisp.h (multibyte_char_to_unibyte, multibyte_char_to_unibyte_safe):
+        Remove prototypes.
+        * character.c (multibyte_char_to_unibyte)
+        (multibyte_char_to_unibyte_safe): Remove; no longer used.
+        * character.h (make_char): Remove; unused.
+        (CHAR_TO_BYTE8, CHAR_TO_BYTE_SAFE): Simplify.
+        (ASCII_BYTE_P): Remove; ASCII_CHAR_P does the same thing.
+        * buffer.c, charset.c, charset.h, cmds.c, coding.c, editfns.c:
+        * fileio.c, indent.c, insdel.c, keyboard.c, lread.c, print.c:
+        * search.c, term.c, xdisp.c, xterm.c: Related users changed.
+
 2014-06-22  Mario Lang  <mlang@delysid.org>
 
         * w32fns.c (Fw32_shell_execute): The the -> the.
diff --git a/src/buffer.c b/src/buffer.c
index 909b3779b06..d6f6b2c7703 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -2530,7 +2530,7 @@ current buffer is cleared.  */)
               p = GAP_END_ADDR;
               stop = Z;
             }
-          if (ASCII_BYTE_P (*p))
+          if (ASCII_CHAR_P (*p))
             p++, pos++;
           else if (CHAR_BYTE8_HEAD_P (*p))
             {
@@ -2602,7 +2602,7 @@ current buffer is cleared.  */)
               stop = Z;
             }
 
-          if (ASCII_BYTE_P (*p))
+          if (ASCII_CHAR_P (*p))
             p++, pos++;
           else if (EQ (flag, Qt)
                    && ! CHAR_BYTE8_HEAD_P (*p)
diff --git a/src/character.c b/src/character.c
index 12a95203527..a8e48dfd774 100644
--- a/src/character.c
+++ b/src/character.c
@@ -233,32 +233,6 @@ translate_char (Lisp_Object table, int c)
   return c;
 }
 
-/* Convert ASCII or 8-bit character C to unibyte.  If C is none of
-   them, return (C & 0xFF).  */
-
-int
-multibyte_char_to_unibyte (int c)
-{
-  if (c < 0x80)
-    return c;
-  if (CHAR_BYTE8_P (c))
-    return CHAR_TO_BYTE8 (c);
-  return (c & 0xFF);
-}
-
-/* Like multibyte_char_to_unibyte, but return -1 if C is not supported
-   by charset_unibyte.  */
-
-int
-multibyte_char_to_unibyte_safe (int c)
-{
-  if (c < 0x80)
-    return c;
-  if (CHAR_BYTE8_P (c))
-    return CHAR_TO_BYTE8 (c);
-  return -1;
-}
-
 DEFUN ("characterp", Fcharacterp, Scharacterp, 1, 2, 0,
        doc: /* Return non-nil if OBJECT is a character.
 In Emacs Lisp, characters are represented by character codes, which
diff --git a/src/character.h b/src/character.h
index 6f243a1392d..18aad5b8f41 100644
--- a/src/character.h
+++ b/src/character.h
@@ -67,20 +67,15 @@ INLINE_HEADER_BEGIN
 #define BYTE8_TO_CHAR(byte) ((byte) + 0x3FFF00)
 
 #define UNIBYTE_TO_CHAR(byte) \
-  (ASCII_BYTE_P (byte) ? (byte) : BYTE8_TO_CHAR (byte))
+  (ASCII_CHAR_P (byte) ? (byte) : BYTE8_TO_CHAR (byte))
 
 /* Return the raw 8-bit byte for character C.  */
-#define CHAR_TO_BYTE8(c)        \
-  (CHAR_BYTE8_P (c)             \
-   ? (c) - 0x3FFF00             \
-   : multibyte_char_to_unibyte (c))
+#define CHAR_TO_BYTE8(c) (CHAR_BYTE8_P (c) ? (c) - 0x3FFF00 : (c & 0xFF))
 
 /* Return the raw 8-bit byte for character C,
    or -1 if C doesn't correspond to a byte.  */
-#define CHAR_TO_BYTE_SAFE(c)    \
-  (CHAR_BYTE8_P (c)             \
-   ? (c) - 0x3FFF00             \
-   : multibyte_char_to_unibyte_safe (c))
+#define CHAR_TO_BYTE_SAFE(c)                                            \
+  (ASCII_CHAR_P (c) ? c : (CHAR_BYTE8_P (c) ? (c) - 0x3FFF00 : -1))
 
 /* Nonzero iff BYTE is the 1st byte of a multibyte form of a character
    that corresponds to a raw 8-bit byte.  */
@@ -101,13 +96,6 @@ INLINE_HEADER_BEGIN
 /* This is the maximum byte length of multibyte form.  */
 #define MAX_MULTIBYTE_LENGTH 5
 
-/* Return a Lisp character whose character code is C.  Assumes C is
-   a valid character code.  */
-#define make_char(c) make_number (c)
-
-/* Nonzero iff C is an ASCII byte.  */
-#define ASCII_BYTE_P(c) UNSIGNED_CMP (c, <, 0x80)
-
 /* Nonzero iff X is a character.  */
 #define CHARACTERP(x) (NATNUMP (x) && XFASTINT (x) <= MAX_CHAR)
 
@@ -222,7 +210,7 @@ INLINE_HEADER_BEGIN
 
 /* Nonzero iff BYTE starts a character in a multibyte form.
    This is equivalent to:
-        (ASCII_BYTE_P (byte) || LEADING_CODE_P (byte))  */
+        (ASCII_CHAR_P (byte) || LEADING_CODE_P (byte))  */
 #define CHAR_HEAD_P(byte) (((byte) & 0xC0) != 0x80)
 
 /* How many bytes a character that starts with BYTE occupies in a
diff --git a/src/charset.c b/src/charset.c
index baa692232c7..341ac356aff 100644
--- a/src/charset.c
+++ b/src/charset.c
@@ -389,12 +389,12 @@ load_charset_map (struct charset *charset, struct charset_map_entries *entries,
         {
           if (ascii_compatible_p)
             {
-              if (! ASCII_BYTE_P (from_c))
+              if (! ASCII_CHAR_P (from_c))
                 {
                   if (from_c < nonascii_min_char)
                     nonascii_min_char = from_c;
                 }
-              else if (! ASCII_BYTE_P (to_c))
+              else if (! ASCII_CHAR_P (to_c))
                 {
                   nonascii_min_char = 0x80;
                 }
@@ -1522,7 +1522,7 @@ find_charsets_in_text (const unsigned char *ptr, ptrdiff_t nchars,
 
             if (!NILP (table))
               c = translate_char (table, c);
-            if (ASCII_BYTE_P (c))
+            if (ASCII_CHAR_P (c))
               ASET (charsets, charset_ascii, Qt);
             else
               ASET (charsets, charset_eight_bit, Qt);
diff --git a/src/charset.h b/src/charset.h
index 32c624beff8..4176ce5ecc6 100644
--- a/src/charset.h
+++ b/src/charset.h
@@ -403,7 +403,7 @@ extern Lisp_Object Vchar_charset_set;
    Try some optimization before calling decode_char.  */
 
 #define DECODE_CHAR(charset, code)                                      \
-  ((ASCII_BYTE_P (code) && (charset)->ascii_compatible_p)               \
+  ((ASCII_CHAR_P (code) && (charset)->ascii_compatible_p)               \
    ? (code)                                                             \
    : ((code) < (charset)->min_code || (code) > (charset)->max_code)     \
    ? -1                                                                 \
diff --git a/src/cmds.c b/src/cmds.c
index 828fea3d753..20234638778 100644
--- a/src/cmds.c
+++ b/src/cmds.c
@@ -359,9 +359,7 @@ internal_self_insert (int c, EMACS_INT n)
     }
   else
     {
-      str[0] = (SINGLE_BYTE_CHAR_P (c)
-                ? c
-                : multibyte_char_to_unibyte (c));
+      str[0] = SINGLE_BYTE_CHAR_P (c) ? c : CHAR_TO_BYTE8 (c);
       len = 1;
     }
   if (!NILP (overwrite)
diff --git a/src/coding.c b/src/coding.c
index fbe14f1695f..16dc37a3f20 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -1485,7 +1485,7 @@ decode_coding_utf_8 (struct coding_system *coding)
       src = src_base;
       consumed_chars = consumed_chars_base;
       ONE_MORE_BYTE (c);
-      *charbuf++ = ASCII_BYTE_P (c) ? c : BYTE8_TO_CHAR (c);
+      *charbuf++ = ASCII_CHAR_P (c) ? c : BYTE8_TO_CHAR (c);
       coding->errors++;
     }
 
@@ -1725,7 +1725,7 @@ decode_coding_utf_16 (struct coding_system *coding)
         ONE_MORE_BYTE (c2);
       if (c2 < 0)
         {
-          *charbuf++ = ASCII_BYTE_P (c1) ? c1 : BYTE8_TO_CHAR (c1);
+          *charbuf++ = ASCII_CHAR_P (c1) ? c1 : BYTE8_TO_CHAR (c1);
           *charbuf++ = -c2;
           continue;
         }
@@ -2108,7 +2108,7 @@ emacs_mule_char (struct coding_system *coding, const unsigned char *src,
 
         case 1:
           code = c;
-          charset_ID = ASCII_BYTE_P (code) ? charset_ascii : charset_eight_bit;
+          charset_ID = ASCII_CHAR_P (code) ? charset_ascii : charset_eight_bit;
           break;
 
         default:
@@ -2596,7 +2596,7 @@ decode_coding_emacs_mule (struct coding_system *coding)
       src = src_base;
       consumed_chars = consumed_chars_base;
       ONE_MORE_BYTE (c);
-      *charbuf++ = ASCII_BYTE_P (c) ? c : BYTE8_TO_CHAR (c);
+      *charbuf++ = ASCII_CHAR_P (c) ? c : BYTE8_TO_CHAR (c);
       char_offset++;
       coding->errors++;
     }
@@ -3573,7 +3573,7 @@ decode_coding_iso_2022 (struct coding_system *coding)
 
       if (CODING_ISO_EXTSEGMENT_LEN (coding) > 0)
         {
-          *charbuf++ = ASCII_BYTE_P (c1) ? c1 : BYTE8_TO_CHAR (c1);
+          *charbuf++ = ASCII_CHAR_P (c1) ? c1 : BYTE8_TO_CHAR (c1);
           char_offset++;
           CODING_ISO_EXTSEGMENT_LEN (coding)--;
           continue;
@@ -3600,7 +3600,7 @@ decode_coding_iso_2022 (struct coding_system *coding)
             }
           else
             {
-              *charbuf++ = ASCII_BYTE_P (c1) ? c1 : BYTE8_TO_CHAR (c1);
+              *charbuf++ = ASCII_CHAR_P (c1) ? c1 : BYTE8_TO_CHAR (c1);
               char_offset++;
             }
           continue;
@@ -3974,7 +3974,7 @@ decode_coding_iso_2022 (struct coding_system *coding)
           MAYBE_FINISH_COMPOSITION ();
           for (; src_base < src; src_base++, char_offset++)
             {
-              if (ASCII_BYTE_P (*src_base))
+              if (ASCII_CHAR_P (*src_base))
                 *charbuf++ = *src_base;
               else
                 *charbuf++ = BYTE8_TO_CHAR (*src_base);
@@ -4004,7 +4004,7 @@ decode_coding_iso_2022 (struct coding_system *coding)
       src = src_base;
       consumed_chars = consumed_chars_base;
       ONE_MORE_BYTE (c);
-      *charbuf++ = c < 0 ? -c : ASCII_BYTE_P (c) ? c : BYTE8_TO_CHAR (c);
+      *charbuf++ = c < 0 ? -c : ASCII_CHAR_P (c) ? c : BYTE8_TO_CHAR (c);
       char_offset++;
       coding->errors++;
       /* Reset the invocation and designation status to the safest
@@ -5640,7 +5640,7 @@ decode_coding_charset (struct coding_system *coding)
       src = src_base;
       consumed_chars = consumed_chars_base;
       ONE_MORE_BYTE (c);
-      *charbuf++ = c < 0 ? -c : ASCII_BYTE_P (c) ? c : BYTE8_TO_CHAR (c);
+      *charbuf++ = c < 0 ? -c : ASCII_CHAR_P (c) ? c : BYTE8_TO_CHAR (c);
       char_offset++;
       coding->errors++;
     }
@@ -9031,13 +9031,13 @@ DEFUN ("find-coding-systems-region-internal",
     p = pbeg = BYTE_POS_ADDR (start_byte);
   pend = p + (end_byte - start_byte);
 
-  while (p < pend && ASCII_BYTE_P (*p)) p++;
-  while (p < pend && ASCII_BYTE_P (*(pend - 1))) pend--;
+  while (p < pend && ASCII_CHAR_P (*p)) p++;
+  while (p < pend && ASCII_CHAR_P (*(pend - 1))) pend--;
 
   work_table = Fmake_char_table (Qnil, Qnil);
   while (p < pend)
     {
-      if (ASCII_BYTE_P (*p))
+      if (ASCII_CHAR_P (*p))
         p++;
       else
         {
@@ -9169,7 +9169,7 @@ to the string.  */)
       int c;
 
       if (ascii_compatible)
-        while (p < stop && ASCII_BYTE_P (*p))
+        while (p < stop && ASCII_CHAR_P (*p))
           p++, from++;
       if (p >= stop)
         {
@@ -9285,12 +9285,12 @@ is nil.  */)
     p = pbeg = BYTE_POS_ADDR (start_byte);
   pend = p + (end_byte - start_byte);
 
-  while (p < pend && ASCII_BYTE_P (*p)) p++, pos++;
-  while (p < pend && ASCII_BYTE_P (*(pend - 1))) pend--;
+  while (p < pend && ASCII_CHAR_P (*p)) p++, pos++;
+  while (p < pend && ASCII_CHAR_P (*(pend - 1))) pend--;
 
   while (p < pend)
     {
-      if (ASCII_BYTE_P (*p))
+      if (ASCII_CHAR_P (*p))
         p++;
       else
         {
@@ -9598,7 +9598,7 @@ Return the corresponding character.  */)
   CHECK_CODING_SYSTEM_GET_SPEC (Vsjis_coding_system, spec);
   attrs = AREF (spec, 0);
 
-  if (ASCII_BYTE_P (ch)
+  if (ASCII_CHAR_P (ch)
       && ! NILP (CODING_ATTR_ASCII_COMPAT (attrs)))
     return code;
 
@@ -9679,7 +9679,7 @@ Return the corresponding character.  */)
   CHECK_CODING_SYSTEM_GET_SPEC (Vbig5_coding_system, spec);
   attrs = AREF (spec, 0);
 
-  if (ASCII_BYTE_P (ch)
+  if (ASCII_CHAR_P (ch)
       && ! NILP (CODING_ATTR_ASCII_COMPAT (attrs)))
     return code;
 
diff --git a/src/editfns.c b/src/editfns.c
index 40fac27ba47..e8d4478f2f6 100644
--- a/src/editfns.c
+++ b/src/editfns.c
@@ -2238,7 +2238,7 @@ general_insert_function (void (*insert_func)
             len = CHAR_STRING (c, str);
           else
             {
-              str[0] = ASCII_CHAR_P (c) ? c : multibyte_char_to_unibyte (c);
+              str[0] = CHAR_TO_BYTE8 (c);
               len = 1;
             }
           (*insert_func) ((char *) str, len);
@@ -2852,7 +2852,7 @@ Both characters must have the same length of multi-byte form.  */)
       len = CHAR_STRING (fromc, fromstr);
       if (CHAR_STRING (toc, tostr) != len)
         error ("Characters in `subst-char-in-region' have different byte-lengths");
-      if (!ASCII_BYTE_P (*tostr))
+      if (!ASCII_CHAR_P (*tostr))
         {
           /* If *TOSTR is in the range 0x80..0x9F and TOCHAR is not a
              complete multibyte character, it may be combined with the
@@ -2945,7 +2945,7 @@ Both characters must have the same length of multi-byte form.  */)
                   : ((pos_byte_next < Z_BYTE
                       && ! CHAR_HEAD_P (FETCH_BYTE (pos_byte_next)))
                      || (pos_byte > BEG_BYTE
-                         && ! ASCII_BYTE_P (FETCH_BYTE (pos_byte - 1))))))
+                         && ! ASCII_CHAR_P (FETCH_BYTE (pos_byte - 1))))))
             {
               Lisp_Object tem, string;
 
@@ -3126,7 +3126,7 @@ It returns the number of characters changed.  */)
               else
                 {
                   nc = tt[oc];
-                  if (! ASCII_BYTE_P (nc) && multibyte)
+                  if (! ASCII_CHAR_P (nc) && multibyte)
                     {
                       str_len = BYTE8_STRING (nc, buf);
                       str = buf;
@@ -3877,7 +3877,7 @@ usage: (format STRING &rest OBJECTS)  */)
 
                   if (p > buf
                       && multibyte
-                      && !ASCII_BYTE_P (*((unsigned char *) p - 1))
+                      && !ASCII_CHAR_P (*((unsigned char *) p - 1))
                       && STRING_MULTIBYTE (args[n])
                       && !CHAR_HEAD_P (SREF (args[n], 0)))
                     maybe_combine_byte = 1;
@@ -4167,7 +4167,7 @@ usage: (format STRING &rest OBJECTS)  */)
             {
               /* Copy a whole multibyte character.  */
               if (p > buf
-                  && !ASCII_BYTE_P (*((unsigned char *) p - 1))
+                  && !ASCII_CHAR_P (*((unsigned char *) p - 1))
                   && !CHAR_HEAD_P (*format))
                 maybe_combine_byte = 1;
 
@@ -4181,7 +4181,7 @@ usage: (format STRING &rest OBJECTS)  */)
           else
             {
               unsigned char uc = *format++;
-              if (! multibyte || ASCII_BYTE_P (uc))
+              if (! multibyte || ASCII_CHAR_P (uc))
                 convbytes = 1;
               else
                 {
diff --git a/src/fileio.c b/src/fileio.c
index c7736661207..f0bd75b170e 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -990,7 +990,7 @@ filesystem tree, not (expand-file-name ".."  dirname).  */)
         {
           unsigned char *p = SDATA (name);
 
-          while (*p && ASCII_BYTE_P (*p))
+          while (*p && ASCII_CHAR_P (*p))
             p++;
           if (*p == '\0')
             {
diff --git a/src/indent.c b/src/indent.c
index 711792f75cd..79af42c5f7e 100644
--- a/src/indent.c
+++ b/src/indent.c
@@ -920,7 +920,7 @@ position_indentation (ptrdiff_t pos_byte)
           column += tab_width - column % tab_width;
           break;
         default:
-          if (ASCII_BYTE_P (p[-1])
+          if (ASCII_CHAR_P (p[-1])
               || NILP (BVAR (current_buffer, enable_multibyte_characters)))
             return column;
           {
diff --git a/src/insdel.c b/src/insdel.c
index 2894af75348..876e2869978 100644
--- a/src/insdel.c
+++ b/src/insdel.c
@@ -701,7 +701,7 @@ count_combining_after (const unsigned char *string,
         (2) POS is the last of the current buffer.
         (3) A character at POS can't be a following byte of multibyte
             character.  */
-  if (length > 0 && ASCII_BYTE_P (string[length - 1])) /* case (1) */
+  if (length > 0 && ASCII_CHAR_P (string[length - 1])) /* case (1) */
     return 0;
   if (pos_byte == Z_BYTE)       /* case (2) */
     return 0;
diff --git a/src/keyboard.c b/src/keyboard.c
index 1da300b77cc..936d6687908 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -2084,7 +2084,7 @@ make_ctrl_char (int c)
   /* Save the upper bits here.  */
   int upper = c & ~0177;
 
-  if (! ASCII_BYTE_P (c))
+  if (! ASCII_CHAR_P (c))
     return c |= ctrl_modifier;
 
   c &= 0177;
diff --git a/src/lisp.h b/src/lisp.h
index 8ad8e80da4b..0b9d3565433 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3433,8 +3433,6 @@ extern void syms_of_coding (void);
 /* Defined in character.c.  */
 extern ptrdiff_t chars_in_text (const unsigned char *, ptrdiff_t);
 extern ptrdiff_t multibyte_chars_in_text (const unsigned char *, ptrdiff_t);
-extern int multibyte_char_to_unibyte (int) ATTRIBUTE_CONST;
-extern int multibyte_char_to_unibyte_safe (int) ATTRIBUTE_CONST;
 extern void syms_of_character (void);
 
 /* Defined in charset.c.  */
diff --git a/src/lread.c b/src/lread.c
index 41ea1f19227..f252993207d 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -213,7 +213,7 @@ readchar (Lisp_Object readcharfun, bool *multibyte)
       else
         {
           c = BUF_FETCH_BYTE (inbuffer, pt_byte);
-          if (! ASCII_BYTE_P (c))
+          if (! ASCII_CHAR_P (c))
             c = BYTE8_TO_CHAR (c);
           pt_byte++;
         }
@@ -242,7 +242,7 @@ readchar (Lisp_Object readcharfun, bool *multibyte)
       else
         {
           c = BUF_FETCH_BYTE (inbuffer, bytepos);
-          if (! ASCII_BYTE_P (c))
+          if (! ASCII_CHAR_P (c))
             c = BYTE8_TO_CHAR (c);
           bytepos++;
         }
@@ -324,7 +324,7 @@ readchar (Lisp_Object readcharfun, bool *multibyte)
     return c;
   if (multibyte)
     *multibyte = 1;
-  if (ASCII_BYTE_P (c))
+  if (ASCII_CHAR_P (c))
     return c;
   if (emacs_mule_encoding)
     return read_emacs_mule_char (c, readbyte, readcharfun);
diff --git a/src/print.c b/src/print.c
index 475be9ec285..9050a0cb773 100644
--- a/src/print.c
+++ b/src/print.c
@@ -1472,7 +1472,7 @@ print_object (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag)
                   strout (outbuf, len, len, printcharfun);
                 }
               else if (! multibyte
-                       && SINGLE_BYTE_CHAR_P (c) && ! ASCII_BYTE_P (c)
+                       && SINGLE_BYTE_CHAR_P (c) && ! ASCII_CHAR_P (c)
                        && print_escape_nonascii)
                 {
                   /* When printing in a multibyte buffer
diff --git a/src/search.c b/src/search.c
index dc4820d8588..ecfb2352144 100644
--- a/src/search.c
+++ b/src/search.c
@@ -1416,7 +1416,7 @@ search_buffer (Lisp_Object string, ptrdiff_t pos, ptrdiff_t pos_byte,
 
                       while (boyer_moore_ok)
                         {
-                          if (ASCII_BYTE_P (inverse))
+                          if (ASCII_CHAR_P (inverse))
                             {
                               if (this_char_base > 0)
                                 boyer_moore_ok = 0;
@@ -1827,7 +1827,7 @@ boyer_moore (EMACS_INT n, unsigned char *base_pat,
              matching with CHAR_BASE are to be checked.  */
           int ch = -1;
 
-          if (ASCII_BYTE_P (*ptr) || ! multibyte)
+          if (ASCII_CHAR_P (*ptr) || ! multibyte)
             ch = *ptr;
           else if (char_base
                    && ((pat_end - ptr) == 1 || CHAR_HEAD_P (ptr[1])))
@@ -2596,7 +2596,7 @@ since only regular expressions have distinguished subexpressions.  */)
             {
               FETCH_STRING_CHAR_ADVANCE_NO_CHECK (c, newtext, pos, pos_byte);
               if (!buf_multibyte)
-                c = multibyte_char_to_unibyte (c);
+                c = CHAR_TO_BYTE8 (c);
             }
           else
             {
@@ -2619,7 +2619,7 @@ since only regular expressions have distinguished subexpressions.  */)
                   FETCH_STRING_CHAR_ADVANCE_NO_CHECK (c, newtext,
                                                       pos, pos_byte);
                   if (!buf_multibyte && !ASCII_CHAR_P (c))
-                    c = multibyte_char_to_unibyte (c);
+                    c = CHAR_TO_BYTE8 (c);
                 }
               else
                 {
diff --git a/src/term.c b/src/term.c
index 642907979aa..d4bb7e1bd32 100644
--- a/src/term.c
+++ b/src/term.c
@@ -1861,7 +1861,7 @@ produce_glyphless_glyph (struct it *it, Lisp_Object acronym)
             acronym = XCDR (acronym);
           buf[0] = '[';
           str = STRINGP (acronym) ? SSDATA (acronym) : "";
-          for (len = 0; len < 6 && str[len] && ASCII_BYTE_P (str[len]); len++)
+          for (len = 0; len < 6 && str[len] && ASCII_CHAR_P (str[len]); len++)
             buf[1 + len] = str[len];
           buf[1 + len] = ']';
           len += 2;
diff --git a/src/xdisp.c b/src/xdisp.c
index 8711487780c..31d293143f3 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -8269,7 +8269,7 @@ next_element_from_buffer (struct it *it)
 
       /* Get the next character, maybe multibyte.  */
       p = BYTE_POS_ADDR (IT_BYTEPOS (*it));
-      if (it->multibyte_p && !ASCII_BYTE_P (*p))
+      if (it->multibyte_p && !ASCII_CHAR_P (*p))
         it->c = STRING_CHAR_AND_LENGTH (p, it->len);
       else
         it->c = *p, it->len = 1;
@@ -9932,9 +9932,7 @@ message_dolog (const char *m, ptrdiff_t nbytes, bool nlflag, bool multibyte)
           for (i = 0; i < nbytes; i += char_bytes)
             {
               c = string_char_and_length (msg + i, &char_bytes);
-              work[0] = (ASCII_CHAR_P (c)
-                         ? c
-                         : multibyte_char_to_unibyte (c));
+              work[0] = CHAR_TO_BYTE8 (c);
               insert_1_both (work, 1, 1, 1, 0, 0);
             }
         }
@@ -25781,7 +25779,7 @@ produce_glyphless_glyph (struct it *it, int for_no_font, Lisp_Object acronym)
           sprintf (buf, "%0*X", it->c < 0x10000 ? 4 : 6, it->c);
           str = buf;
         }
-      for (len = 0; str[len] && ASCII_BYTE_P (str[len]) && len < 6; len++)
+      for (len = 0; str[len] && ASCII_CHAR_P (str[len]) && len < 6; len++)
         code[len] = font->driver->encode_char (font, str[len]);
       upper_len = (len + 1) / 2;
       font->driver->text_extents (font, code, upper_len,
diff --git a/src/xterm.c b/src/xterm.c
index a7f77bdb282..45bb7b2a918 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -6460,7 +6460,7 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 
             for (i = 0, nchars = 0; i < nbytes; i++)
               {
-                if (ASCII_BYTE_P (copy_bufptr[i]))
+                if (ASCII_CHAR_P (copy_bufptr[i]))
                   nchars++;
                 STORE_KEYSYM_FOR_DEBUG (copy_bufptr[i]);
               }