* lisp.h (UNSIGNED_CMP): New macro.

This fixes comparison bugs on 64-bit hosts.
(ASCII_CHAR_P): Use it.
* casefiddle.c (casify_object):
* character.h (ASCII_BYTE_P, CHAR_VALID_P):
(SINGLE_BYTE_CHAR_P, CHAR_STRING):
* composite.h (COMPOSITION_ENCODE_RULE_VALID):
* dispextern.h (FACE_FROM_ID):
* keyboard.c (read_char): Use UNSIGNED_CMP.

7 files changed, 38 insertions, 12 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 82fd3526785..cb3ed502c96 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,15 @@
+2011-06-12  Paul Eggert  <eggert@cs.ucla.edu>
+
+        * lisp.h (UNSIGNED_CMP): New macro.
+        This fixes comparison bugs on 64-bit hosts.
+        (ASCII_CHAR_P): Use it.
+        * casefiddle.c (casify_object):
+        * character.h (ASCII_BYTE_P, CHAR_VALID_P):
+        (SINGLE_BYTE_CHAR_P, CHAR_STRING):
+        * composite.h (COMPOSITION_ENCODE_RULE_VALID):
+        * dispextern.h (FACE_FROM_ID):
+        * keyboard.c (read_char): Use UNSIGNED_CMP.
+
 2011-06-11  Paul Eggert  <eggert@cs.ucla.edu>
 
         * xmenu.c (dialog_selection_callback) [!USE_GTK]: Cast to intptr_t,
diff --git a/src/casefiddle.c b/src/casefiddle.c
index 9f286d73a5e..1a0a62f273c 100644
--- a/src/casefiddle.c
+++ b/src/casefiddle.c
@@ -52,7 +52,7 @@ casify_object (enum case_action flag, Lisp_Object obj)
       /* If the character has higher bits set
          above the flags, return it unchanged.
          It is not a real character.  */
-      if ((unsigned) XFASTINT (obj) > (unsigned) flagbits)
+      if (UNSIGNED_CMP (XFASTINT (obj), >, flagbits))
         return obj;
 
       c1 = XFASTINT (obj) & ~flagbits;
diff --git a/src/character.h b/src/character.h
index 884833775de..695a55be3fa 100644
--- a/src/character.h
+++ b/src/character.h
@@ -102,13 +102,13 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #define make_char(c) make_number (c)
 
 /* Nonzero iff C is an ASCII byte.  */
-#define ASCII_BYTE_P(c) ((unsigned) (c) < 0x80)
+#define ASCII_BYTE_P(c) UNSIGNED_CMP (c, <, 0x80)
 
 /* Nonzero iff X is a character.  */
 #define CHARACTERP(x) (NATNUMP (x) && XFASTINT (x) <= MAX_CHAR)
 
 /* Nonzero iff C is valid as a character code.  GENERICP is not used.  */
-#define CHAR_VALID_P(c, genericp) ((unsigned) (c) <= MAX_CHAR)
+#define CHAR_VALID_P(c, genericp) UNSIGNED_CMP (c, <=, MAX_CHAR)
 
 /* Check if Lisp object X is a character or not.  */
 #define CHECK_CHARACTER(x) \
@@ -129,7 +129,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
   } while (0)
 
 /* Nonzero iff C is a character of code less than 0x100.  */
-#define SINGLE_BYTE_CHAR_P(c) ((unsigned) (c) < 0x100)
+#define SINGLE_BYTE_CHAR_P(c) UNSIGNED_CMP (c, <, 0x100)
 
 /* Nonzero if character C has a printable glyph.  */
 #define CHAR_PRINTABLE_P(c)     \
@@ -161,14 +161,14 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    Returns the length of the multibyte form.  */
 
 #define CHAR_STRING(c, p)                       \
-  ((unsigned) (c) <= MAX_1_BYTE_CHAR            \
+  (UNSIGNED_CMP (c, <=, MAX_1_BYTE_CHAR)        \
    ? ((p)[0] = (c),                             \
       1)                                        \
-   : (unsigned) (c) <= MAX_2_BYTE_CHAR          \
+   : UNSIGNED_CMP (c, <=, MAX_2_BYTE_CHAR)      \
    ? ((p)[0] = (0xC0 | ((c) >> 6)),             \
       (p)[1] = (0x80 | ((c) & 0x3F)),           \
       2)                                        \
-   : (unsigned) (c) <= MAX_3_BYTE_CHAR          \
+   : UNSIGNED_CMP (c, <=, MAX_3_BYTE_CHAR)      \
    ? ((p)[0] = (0xE0 | ((c) >> 12)),            \
       (p)[1] = (0x80 | (((c) >> 6) & 0x3F)),    \
       (p)[2] = (0x80 | ((c) & 0x3F)),           \
diff --git a/src/composite.h b/src/composite.h
index 0f81911f0b0..8cedfdbe352 100644
--- a/src/composite.h
+++ b/src/composite.h
@@ -151,7 +151,7 @@ extern Lisp_Object composition_temp;
 /* Nonzero if the global reference point GREF and new reference point NREF are
    valid.  */
 #define COMPOSITION_ENCODE_RULE_VALID(gref, nref)       \
-  ((unsigned) (gref) < 12 && (unsigned) (nref) < 12)
+  (UNSIGNED_CMP (gref, <, 12) && UNSIGNED_CMP (nref, <, 12))
 
 /* Return encoded composition rule for the pair of global reference
    point GREF and new reference point NREF.  Arguments must be valid.  */
diff --git a/src/dispextern.h b/src/dispextern.h
index 211a1b06659..75ebc462ce4 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -1729,7 +1729,7 @@ struct face_cache
    face doesn't exist.  */
 
 #define FACE_FROM_ID(F, ID)                             \
-     (((unsigned) (ID) < FRAME_FACE_CACHE (F)->used)    \
+     (UNSIGNED_CMP (ID, <, FRAME_FACE_CACHE (F)->used)  \
       ? FRAME_FACE_CACHE (F)->faces_by_id[ID]           \
       : NULL)
 
diff --git a/src/keyboard.c b/src/keyboard.c
index 89483972a65..0bacc2fa28f 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -2906,9 +2906,13 @@ read_char (int commandflag, int nmaps, Lisp_Object *maps, Lisp_Object prev_event
         goto exit;
 
       if ((STRINGP (KVAR (current_kboard, Vkeyboard_translate_table))
-           && SCHARS (KVAR (current_kboard, Vkeyboard_translate_table)) > (unsigned) XFASTINT (c))
+           && UNSIGNED_CMP (XFASTINT (c), <,
+                            SCHARS (KVAR (current_kboard,
+                                          Vkeyboard_translate_table))))
           || (VECTORP (KVAR (current_kboard, Vkeyboard_translate_table))
-              && ASIZE (KVAR (current_kboard, Vkeyboard_translate_table)) > (unsigned) XFASTINT (c))
+              && UNSIGNED_CMP (XFASTINT (c), <,
+                               ASIZE (KVAR (current_kboard,
+                                            Vkeyboard_translate_table))))
           || (CHAR_TABLE_P (KVAR (current_kboard, Vkeyboard_translate_table))
               && CHARACTERP (c)))
         {
diff --git a/src/lisp.h b/src/lisp.h
index 6003daee8fa..4dfed319490 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -911,8 +911,18 @@ struct Lisp_Vector
 
 #endif  /* not __GNUC__ */
 
+/* Compute A OP B, using the unsigned comparison operator OP.  A and B
+   should be integer expressions.  This is not the same as
+   mathemeatical comparison; for example, UNSIGNED_CMP (0, <, -1)
+   returns 1.  For efficiency, prefer plain unsigned comparison if A
+   and B's sizes both fit (after integer promotion).  */
+#define UNSIGNED_CMP(a, op, b)                                          \
+  (max (sizeof ((a) + 0), sizeof ((b) + 0)) <= sizeof (unsigned)        \
+   ? ((a) + (unsigned) 0) op ((b) + (unsigned) 0)                       \
+   : ((a) + (uintmax_t) 0) op ((b) + (uintmax_t) 0))
+
 /* Nonzero iff C is an ASCII character.  */
-#define ASCII_CHAR_P(c) ((unsigned) (c) < 0x80)
+#define ASCII_CHAR_P(c) UNSIGNED_CMP (c, <, 0x80)
 
 /* Almost equivalent to Faref (CT, IDX) with optimization for ASCII
    characters.  Do not check validity of CT.  */