diff --git a/src/string/memccpy.c b/src/string/memccpy.c
index 7c233d5..5c8b672 100644
--- a/src/string/memccpy.c
+++ b/src/string/memccpy.c
@@ -11,19 +11,21 @@ void *memccpy(void *restrict dest, const void *restrict src, int c, size_t n)
 {
 	unsigned char *d = dest;
 	const unsigned char *s = src;
-	size_t *wd, k;
-	const size_t *ws;
 
 	c = (unsigned char)c;
+#ifdef __GNUC__
+	size_t __attribute__((__may_alias__)) *wd;
+	const size_t __attribute__((__may_alias__)) *ws;
 	if (((uintptr_t)s & ALIGN) == ((uintptr_t)d & ALIGN)) {
 		for (; ((uintptr_t)s & ALIGN) && n && (*d=*s)!=c; n--, s++, d++);
 		if ((uintptr_t)s & ALIGN) goto tail;
-		k = ONES * c;
+		size_t k = ONES * c;
 		wd=(void *)d; ws=(const void *)s;
 		for (; n>=sizeof(size_t) && !HASZERO(*ws^k);
 		       n-=sizeof(size_t), ws++, wd++) *wd = *ws;
 		d=(void *)wd; s=(const void *)ws;
 	}
+#endif
 	for (; n && (*d=*s)!=c; n--, s++, d++);
 tail:
 	if (*s==c) return d+1;
diff --git a/src/string/memchr.c b/src/string/memchr.c
index 4daff7b..1038ce6 100644
--- a/src/string/memchr.c
+++ b/src/string/memchr.c
@@ -12,12 +12,14 @@ void *memchr(const void *src, int c, size_t n)
 {
 	const unsigned char *s = src;
 	c = (unsigned char)c;
+
+#ifdef __GNUC__
 	for (; ((uintptr_t)s & ALIGN) && n && *s != c; s++, n--);
-	if (n && *s != c) {
-		const size_t *w;
-		size_t k = ONES * c;
-		for (w = (const void *)s; n>=SS && !HASZERO(*w^k); w++, n-=SS);
-		for (s = (const void *)w; n && *s != c; s++, n--);
-	}
+	const __attribute__((__may_alias__)) size_t *w;
+	size_t k = ONES * c;
+	for (w = (const void *)s; n>=SS && !HASZERO(*w^k); w++, n-=SS);
+	s = (const void *)w;
+#endif
+	for (; n && *s != c; s++, n--);
 	return n ? (void *)s : 0;
 }
diff --git a/src/string/stpcpy.c b/src/string/stpcpy.c
index 54cf9ca..f115d16 100644
--- a/src/string/stpcpy.c
+++ b/src/string/stpcpy.c
@@ -9,9 +9,9 @@
 
 char *__stpcpy(char *restrict d, const char *restrict s)
 {
-	size_t *wd;
-	const size_t *ws;
-
+#ifdef __GNUC__
+	size_t __attribute__((__may_alias__)) *wd;
+	const size_t __attribute__((__may_alias__)) *ws;
 	if ((uintptr_t)s % ALIGN == (uintptr_t)d % ALIGN) {
 		for (; (uintptr_t)s % ALIGN; s++, d++)
 			if (!(*d=*s)) return d;
@@ -19,6 +19,7 @@ char *__stpcpy(char *restrict d, const char *restrict s)
 		for (; !HASZERO(*ws); *wd++ = *ws++);
 		d=(void *)wd; s=(const void *)ws;
 	}
+#endif
 	for (; (*d=*s); s++, d++);
 
 	return d;
diff --git a/src/string/stpncpy.c b/src/string/stpncpy.c
index d6d92ff..099d77c 100644
--- a/src/string/stpncpy.c
+++ b/src/string/stpncpy.c
@@ -9,9 +9,9 @@
 
 char *__stpncpy(char *restrict d, const char *restrict s, size_t n)
 {
-	size_t *wd;
-	const size_t *ws;
-
+#ifdef __GNUC__
+	size_t __attribute__((__may_alias__)) *wd;
+	const size_t __attribute__((__may_alias__)) *ws;
 	if (((uintptr_t)s & ALIGN) == ((uintptr_t)d & ALIGN)) {
 		for (; ((uintptr_t)s & ALIGN) && n && (*d=*s); n--, s++, d++);
 		if (!n || !*s) goto tail;
@@ -20,6 +20,7 @@ char *__stpncpy(char *restrict d, const char *restrict s, size_t n)
 		       n-=sizeof(size_t), ws++, wd++) *wd = *ws;
 		d=(void *)wd; s=(const void *)ws;
 	}
+#endif
 	for (; n && (*d=*s); n--, s++, d++);
 tail:
 	memset(d, 0, n);
diff --git a/src/string/strchrnul.c b/src/string/strchrnul.c
index f2b9ae1..6875ae0 100644
--- a/src/string/strchrnul.c
+++ b/src/string/strchrnul.c
@@ -9,16 +9,18 @@
 
 char *__strchrnul(const char *s, int c)
 {
-	size_t *w, k;
-
 	c = (unsigned char)c;
 	if (!c) return (char *)s + strlen(s);
 
+#ifdef __GNUC__
+	size_t __attribute__((__may_alias__)) *w;
 	for (; (uintptr_t)s % ALIGN; s++)
 		if (!*s || *(unsigned char *)s == c) return (char *)s;
-	k = ONES * c;
+	size_t k = ONES * c;
 	for (w = (void *)s; !HASZERO(*w) && !HASZERO(*w^k); w++);
-	for (s = (void *)w; *s && *(unsigned char *)s != c; s++);
+	s = (void *)w;
+#endif
+	for (; *s && *(unsigned char *)s != c; s++);
 	return (char *)s;
 }
 
diff --git a/src/string/strlcpy.c b/src/string/strlcpy.c
index dcb22f6..a76b7b2 100644
--- a/src/string/strlcpy.c
+++ b/src/string/strlcpy.c
@@ -12,9 +12,10 @@ size_t strlcpy(char *d, const char *s, size_t n)
 {
 	char *d0 = d;
 	size_t *wd;
-	const size_t *ws;
 
 	if (!n--) goto finish;
+#ifdef __GNUC__
+	const __attribute__((__may_alias__)) size_t *ws;
 	if (((uintptr_t)s & ALIGN) == ((uintptr_t)d & ALIGN)) {
 		for (; ((uintptr_t)s & ALIGN) && n && (*d=*s); n--, s++, d++);
 		if (n && *s) {
@@ -24,6 +25,7 @@ size_t strlcpy(char *d, const char *s, size_t n)
 			d=(void *)wd; s=(const void *)ws;
 		}
 	}
+#endif
 	for (; n && (*d=*s); n--, s++, d++);
 	*d = 0;
 finish:
diff --git a/src/string/strlen.c b/src/string/strlen.c
index 929ddcb..27b6d37 100644
--- a/src/string/strlen.c
+++ b/src/string/strlen.c
@@ -10,9 +10,12 @@
 size_t strlen(const char *s)
 {
 	const char *a = s;
-	const size_t *w;
+#ifdef __GNUC__
+	const __attribute__((__may_alias__)) size_t *w;
 	for (; (uintptr_t)s % ALIGN; s++) if (!*s) return s-a;
 	for (w = (const void *)s; !HASZERO(*w); w++);
-	for (s = (const void *)w; *s; s++);
+	s = (const void *)w;
+#endif
+	for (; *s; s++);
 	return s-a;
 }