Change inner loops to use int not YY_CHAR, removing need for separate NUL table

src/dfa.c

@@ -452,30 +452,12 @@ void ntod (void)
 
 	/* Note that the test for ecgroup[0] == numecs below accomplishes
 	 * both (1) and (2) above
+	 *
+	 * New way: we will only use NUL table for fulltbl, because the
+	 * scanner will use an integer instead of YY_CHAR as noted above
 	 */
-	if (!fullspd && ecgroup[0] == numecs) {
-		/* NUL is alone in its equivalence class, which is the
-		 * last one.
-		 */
-		int     use_NUL_table = (numecs == csize);
-
-		if (fulltbl && !use_NUL_table) {
-			/* We still may want to use the table if numecs
-			 * is a power of 2.
-			 */
-			if (numecs <= csize && is_power_of_2(numecs)) {
-				use_NUL_table = true;
-			}
-		}
-
-		if (use_NUL_table)
-			nultrans =
-				allocate_integer_array (current_max_dfas);
-
-		/* From now on, nultrans != nil indicates that we're
-		 * saving null transitions for later, separate encoding.
-		 */
-	}
+	if (fulltbl && ecgroup[0] == numecs && is_power_of_2(numecs))
+		nultrans = allocate_integer_array (current_max_dfas);
 
 
 	if (fullspd) {

src/gen.c

@@ -715,7 +715,16 @@ void genftbl (void)
 
 void gen_next_compressed_state (char *char_map)
 {
-	indent_put2s ("YY_CHAR yy_c = %s;", char_map);
+	/* Formerly YY_CHAR, changed to int because table can now have up to
+	 * 0x101 entries, since we no longer generate a separate NUL table
+	 *
+	 * Note: on x86-64 architecture with gcc -O2, we save an instruction
+	 * in the main loop, since the character can now be zero-extended in
+	 * the process of retrieving it from the input stream or the yy_ec[]
+	 * or yy_meta[] arrays, whereas previously it was zero-extended by a
+	 * register-to-register move just prior to the yy_chk[] table lookup
+	 */
+	indent_put2s ("int yy_c = %s;", char_map);
 
 	/* Save the backing-up info \before/ computing the next state
 	 * because we always compute one more state than needed - we