diff -r 6fb1fb550319 Objects/stringlib/find_max_char.h
--- a/Objects/stringlib/find_max_char.h	Thu Oct 11 18:59:34 2012 -0700
+++ b/Objects/stringlib/find_max_char.h	Fri Oct 12 10:41:04 2012 +0300
@@ -2,6 +2,8 @@
 
 #if STRINGLIB_IS_UNICODE
 
+#if STRINGLIB_SIZEOF_CHAR == 1
+
 /* Mask to quickly check whether a C 'long' contains a
    non-ASCII, UTF8-encoded char. */
 #if (SIZEOF_LONG == 8)
@@ -12,8 +14,6 @@
 # error C 'long' size should be either 4 or 8!
 #endif
 
-#if STRINGLIB_SIZEOF_CHAR == 1
-
 Py_LOCAL_INLINE(Py_UCS4)
 STRINGLIB(find_max_char)(const STRINGLIB_CHAR *begin, const STRINGLIB_CHAR *end)
 {
@@ -41,93 +41,73 @@
     return 127;
 }
 
-#undef ASCII_CHAR_MASK
+#undef UCS1_ASCII_CHAR_MASK
 
 #else /* STRINGLIB_SIZEOF_CHAR == 1 */
 
-#define MASK_ASCII 0xFFFFFF80
-#define MASK_UCS1 0xFFFFFF00
-#define MASK_UCS2 0xFFFF0000
-
-#define MAX_CHAR_ASCII 0x7f
-#define MAX_CHAR_UCS1  0xff
-#define MAX_CHAR_UCS2  0xffff
-#define MAX_CHAR_UCS4  0x10ffff
-
 Py_LOCAL_INLINE(Py_UCS4)
 STRINGLIB(find_max_char)(const STRINGLIB_CHAR *begin, const STRINGLIB_CHAR *end)
 {
+    register Py_UCS4 max_char;
+    Py_ssize_t n = end - begin;
+    const STRINGLIB_CHAR *p = begin;
+    const STRINGLIB_CHAR *unrolled_end = begin + _Py_SIZE_ROUND_DOWN(n, 4);
+
+    max_char = 0x7F;
+    while (p < unrolled_end) {
+        Py_UCS4 ch = p[0] | p[1] | p[2] | p[3];
+        p += 4;
+        if (ch > max_char) {
 #if STRINGLIB_SIZEOF_CHAR == 2
-    const Py_UCS4 mask_limit = MASK_UCS1;
-    const Py_UCS4 max_char_limit = MAX_CHAR_UCS2;
+            if (ch > 0xFF) {
+                /* Limit reached */
+                return 0xFFFF;
+            }
 #elif STRINGLIB_SIZEOF_CHAR == 4
-    const Py_UCS4 mask_limit = MASK_UCS2;
-    const Py_UCS4 max_char_limit = MAX_CHAR_UCS4;
+            if (ch > 0xFFFF) {
+                /* Limit reached */
+                return 0x10FFFF;
+            }
+            else if (ch > 0xFF) {
+                max_char = 0xFFFF;
+            }
 #else
 #error Invalid STRINGLIB_SIZEOF_CHAR (must be 1, 2 or 4)
 #endif
-    register Py_UCS4 mask;
-    Py_ssize_t n = end - begin;
-    const STRINGLIB_CHAR *p = begin;
-    const STRINGLIB_CHAR *unrolled_end = begin + _Py_SIZE_ROUND_DOWN(n, 4);
-    Py_UCS4 max_char;
-
-    max_char = MAX_CHAR_ASCII;
-    mask = MASK_ASCII;
-    while (p < unrolled_end) {
-        STRINGLIB_CHAR bits = p[0] | p[1] | p[2] | p[3];
-        if (bits & mask) {
-            if (mask == mask_limit) {
-                /* Limit reached */
-                return max_char_limit;
+            else {
+                assert(max_char == 0x7F);
+                max_char = 0xFF;
             }
-            if (mask == MASK_ASCII) {
-                max_char = MAX_CHAR_UCS1;
-                mask = MASK_UCS1;
-            }
-            else {
-                /* mask can't be MASK_UCS2 because of mask_limit above */
-                assert(mask == MASK_UCS1);
-                max_char = MAX_CHAR_UCS2;
-                mask = MASK_UCS2;
-            }
-            /* We check the new mask on the same chars in the next iteration */
-            continue;
         }
-        p += 4;
     }
     while (p < end) {
-        if (p[0] & mask) {
-            if (mask == mask_limit) {
+        Py_UCS4 ch = *p++;
+        if (ch > max_char) {
+#if STRINGLIB_SIZEOF_CHAR == 2
+            if (ch > 0xFF) {
                 /* Limit reached */
-                return max_char_limit;
+                return 0xFFFF;
             }
-            if (mask == MASK_ASCII) {
-                max_char = MAX_CHAR_UCS1;
-                mask = MASK_UCS1;
+#elif STRINGLIB_SIZEOF_CHAR == 4
+            if (ch > 0xFFFF) {
+                /* Limit reached */
+                return 0x10FFFF;
             }
+            else if (ch > 0xFF) {
+                max_char = 0xFFFF;
+            }
+#else
+#error Invalid STRINGLIB_SIZEOF_CHAR (must be 1, 2 or 4)
+#endif
             else {
-                /* mask can't be MASK_UCS2 because of mask_limit above */
-                assert(mask == MASK_UCS1);
-                max_char = MAX_CHAR_UCS2;
-                mask = MASK_UCS2;
+                assert(max_char == 0x7F);
+                max_char = 0xFF;
             }
-            /* We check the new mask on the same chars in the next iteration */
-            continue;
         }
-        p++;
     }
     return max_char;
 }
 
-#undef MASK_ASCII
-#undef MASK_UCS1
-#undef MASK_UCS2
-#undef MAX_CHAR_ASCII
-#undef MAX_CHAR_UCS1
-#undef MAX_CHAR_UCS2
-#undef MAX_CHAR_UCS4
-
 #endif /* STRINGLIB_SIZEOF_CHAR == 1 */
 #endif /* STRINGLIB_IS_UNICODE */