diff --git a/sys/sys/ctype_inline.h b/sys/sys/ctype_inline.h
index d416a4591..105cdcb2c 100644
--- a/sys/sys/ctype_inline.h
+++ b/sys/sys/ctype_inline.h
@@ -44,20 +44,20 @@
 #include <sys/featuretest.h>
 
 #include <sys/ctype_bits.h>
-/* LSC: cast to unsigned char in order to prevent char as indice errors. */
-#define	isdigit(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & _CTYPE_N))
-#define	islower(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & _CTYPE_L))
-#define	isspace(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & _CTYPE_S))
-#define	ispunct(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & _CTYPE_P))
-#define	isupper(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & _CTYPE_U))
-#define	isalpha(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & (_CTYPE_U|_CTYPE_L)))
-#define	isxdigit(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & (_CTYPE_N|_CTYPE_X)))
-#define	isalnum(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & (_CTYPE_U|_CTYPE_L|_CTYPE_N)))
-#define	isprint(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & (_CTYPE_P|_CTYPE_U|_CTYPE_L|_CTYPE_N|_CTYPE_B)))
-#define	isgraph(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & (_CTYPE_P|_CTYPE_U|_CTYPE_L|_CTYPE_N)))
-#define	iscntrl(c)	((int)((_ctype_ + 1)[(unsigned char)(c)] & _CTYPE_C))
-#define	tolower(c)	((int)((_tolower_tab_ + 1)[(unsigned char)(c)]))
-#define	toupper(c)	((int)((_toupper_tab_ + 1)[(unsigned char)(c)]))
+
+#define	isdigit(c)	((int)((_ctype_ + 1)[(c)] & _CTYPE_N))
+#define	islower(c)	((int)((_ctype_ + 1)[(c)] & _CTYPE_L))
+#define	isspace(c)	((int)((_ctype_ + 1)[(c)] & _CTYPE_S))
+#define	ispunct(c)	((int)((_ctype_ + 1)[(c)] & _CTYPE_P))
+#define	isupper(c)	((int)((_ctype_ + 1)[(c)] & _CTYPE_U))
+#define	isalpha(c)	((int)((_ctype_ + 1)[(c)] & (_CTYPE_U|_CTYPE_L)))
+#define	isxdigit(c)	((int)((_ctype_ + 1)[(c)] & (_CTYPE_N|_CTYPE_X)))
+#define	isalnum(c)	((int)((_ctype_ + 1)[(c)] & (_CTYPE_U|_CTYPE_L|_CTYPE_N)))
+#define	isprint(c)	((int)((_ctype_ + 1)[(c)] & (_CTYPE_P|_CTYPE_U|_CTYPE_L|_CTYPE_N|_CTYPE_B)))
+#define	isgraph(c)	((int)((_ctype_ + 1)[(c)] & (_CTYPE_P|_CTYPE_U|_CTYPE_L|_CTYPE_N)))
+#define	iscntrl(c)	((int)((_ctype_ + 1)[(c)] & _CTYPE_C))
+#define	tolower(c)	((int)((_tolower_tab_ + 1)[(c)]))
+#define	toupper(c)	((int)((_toupper_tab_ + 1)[(c)]))
 
 #if defined(_XOPEN_SOURCE) || defined(_NETBSD_SOURCE)
 #define	isascii(c)	((unsigned)(c) <= 0177)