-/* Return the canonicalized form of STRING, or NULL if STRING can not be
- parsed. The return value is allocated via xmalloc.
+/* Return 1 if STRING is clearly already in canonical form. This
+ function is conservative; things which it does not recognize are
+ assumed to be non-canonical, and the parser will sort them out
+ afterwards. This speeds up the critical path for alphanumeric
+ identifiers. */
+
+static int
+cp_already_canonical (const char *string)
+{
+ /* Identifier start character [a-zA-Z_]. */
+ if (!ISIDST (string[0]))
+ return 0;
+
+ /* These are the only two identifiers which canonicalize to other
+ than themselves or an error: unsigned -> unsigned int and
+ signed -> int. */
+ if (string[0] == 'u' && strcmp (&string[1], "nsigned") == 0)
+ return 0;
+ else if (string[0] == 's' && strcmp (&string[1], "igned") == 0)
+ return 0;
+
+ /* Identifier character [a-zA-Z0-9_]. */
+ while (ISIDNUM (string[1]))
+ string++;
+
+ if (string[1] == '\0')
+ return 1;
+ else
+ return 0;
+}