-#define isALNUM_LC_utf8(p) isALNUM_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isIDFIRST_LC_utf8(p) isIDFIRST_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isALPHA_LC_utf8(p) isALPHA_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isBLANK_LC_utf8(p) isBLANK_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isSPACE_LC_utf8(p) isSPACE_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isDIGIT_LC_utf8(p) isDIGIT_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isUPPER_LC_utf8(p) isUPPER_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isLOWER_LC_utf8(p) isLOWER_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isALNUMC_LC_utf8(p) isALNUMC_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isCNTRL_LC_utf8(p) isCNTRL_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isGRAPH_LC_utf8(p) isGRAPH_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isPRINT_LC_utf8(p) isPRINT_LC_uvchr(valid_utf8_to_uvchr(p, 0))
-#define isPUNCT_LC_utf8(p) isPUNCT_LC_uvchr(valid_utf8_to_uvchr(p, 0))
+/* For internal core Perl use only. If the input is in the Latin1 range, use
+ * the macro 'macro' on 'p' which is a pointer to a UTF-8 string. Otherwise
+ * use the value given by the 'utf8' parameter. This relies on the fact that
+ * ASCII characters have the same representation whether utf8 or not. Note
+ * that it assumes that the utf8 has been validated, and ignores 'use bytes' */
+#define _generic_LC_utf8_utf8(macro, p, utf8) \
+ (UTF8_IS_INVARIANT(*(p)) \
+ ? macro(*(p)) \
+ : (UTF8_IS_DOWNGRADEABLE_START(*(p))) \
+ ? macro(TWO_BYTE_UTF8_TO_UNI(*(p), *((p)+1))) \
+ : utf8)
+
+#define _generic_LC_utf8(macro, utf8_func, p) \
+ _generic_LC_utf8_utf8(macro, p, utf8_func(p))
+
+#define isALNUM_LC_utf8(p) _generic_LC_utf8(isALNUM_LC, is_utf8_alnum, p)
+#define isIDFIRST_LC_utf8(p) _generic_LC_utf8(isIDFIRST_LC, \
+ _is_utf8_perl_idstart, p)
+#define isALPHA_LC_utf8(p) _generic_LC_utf8(isALPHA_LC, is_utf8_alpha, p)
+#define isBLANK_LC_utf8(p) _generic_LC_utf8(isBLANK_LC, is_HORIZWS_high, p)
+#define isSPACE_LC_utf8(p) _generic_LC_utf8(isSPACE_LC, is_XPERLSPACE_high, p)
+#define isDIGIT_LC_utf8(p) _generic_LC_utf8(isDIGIT_LC, is_utf8_digit, p)
+#define isUPPER_LC_utf8(p) _generic_LC_utf8(isUPPER_LC, is_utf8_upper, p)
+#define isLOWER_LC_utf8(p) _generic_LC_utf8(isLOWER_LC, is_utf8_lower, p)
+#define isALNUMC_LC_utf8(p) _generic_LC_utf8(isALNUMC_LC, is_utf8_alnumc, p)
+#define isCNTRL_LC_utf8(p) _generic_LC_utf8_utf8(isCNTRL_LC, p, 0)
+#define isGRAPH_LC_utf8(p) _generic_LC_utf8(isGRAPH_LC, is_utf8_graph, p)
+#define isPRINT_LC_utf8(p) _generic_LC_utf8(isPRINT_LC, is_utf8_print, p)
+#define isPUNCT_LC_utf8(p) _generic_LC_utf8(isPUNCT_LC, is_utf8_punct, p)