diff --git a/ext/standard/crypt_sha256.c b/ext/standard/crypt_sha256.c
index 5083ee4fc92f0..9e86db6020cdf 100644
--- a/ext/standard/crypt_sha256.c
+++ b/ext/standard/crypt_sha256.c
@@ -377,15 +377,15 @@ char * php_sha256_crypt_r(const char *key, const char *salt, char *buffer, int b
 	SET_ALLOCA_FLAG(use_heap_key);
 	SET_ALLOCA_FLAG(use_heap_salt);
 
-	if ((key - (char *) 0) % __alignof__ (uint32_t) != 0) {
+	if ((uintptr_t)key % __alignof__ (uint32_t) != 0) {
 		tmp_key = (char *) do_alloca(key_len + __alignof__(uint32_t), use_heap_key);
-		key = copied_key = memcpy(tmp_key + __alignof__(uint32_t) - (tmp_key - (char *) 0) % __alignof__(uint32_t), key, key_len);
+		key = copied_key = memcpy(tmp_key + __alignof__(uint32_t) - (uintptr_t)tmp_key % __alignof__(uint32_t), key, key_len);
 	}
 
-	if ((salt - (char *) 0) % __alignof__(uint32_t) != 0) {
+	if ((uintptr_t)salt % __alignof__(uint32_t) != 0) {
 		tmp_salt = (char *) do_alloca(salt_len + 1 + __alignof__(uint32_t), use_heap_salt);
 		salt = copied_salt =
-		memcpy(tmp_salt + __alignof__(uint32_t) - (tmp_salt - (char *) 0) % __alignof__ (uint32_t), salt, salt_len);
+		memcpy(tmp_salt + __alignof__(uint32_t) - (uintptr_t)tmp_salt % __alignof__ (uint32_t), salt, salt_len);
 		copied_salt[salt_len] = 0;
 	}
 
diff --git a/ext/standard/crypt_sha512.c b/ext/standard/crypt_sha512.c
index caeeff750f6ce..6ead7f2964a48 100644
--- a/ext/standard/crypt_sha512.c
+++ b/ext/standard/crypt_sha512.c
@@ -411,15 +411,15 @@ php_sha512_crypt_r(const char *key, const char *salt, char *buffer, int buflen)
 	SET_ALLOCA_FLAG(use_heap_key);
 	SET_ALLOCA_FLAG(use_heap_salt);
 
-	if ((key - (char *) 0) % __alignof__ (uint64_t) != 0) {
+	if ((uintptr_t)key % __alignof__ (uint64_t) != 0) {
 		tmp_key = (char *) do_alloca(key_len + __alignof__ (uint64_t), use_heap_key);
 		key = copied_key =
-		memcpy(tmp_key + __alignof__(uint64_t) - (tmp_key - (char *) 0) % __alignof__(uint64_t), key, key_len);
+		memcpy(tmp_key + __alignof__(uint64_t) - (uintptr_t)tmp_key % __alignof__(uint64_t), key, key_len);
 	}
 
-	if ((salt - (char *) 0) % __alignof__ (uint64_t) != 0) {
+	if ((uintptr_t)salt % __alignof__ (uint64_t) != 0) {
 		tmp_salt = (char *) do_alloca(salt_len + 1 + __alignof__(uint64_t), use_heap_salt);
-		salt = copied_salt = memcpy(tmp_salt + __alignof__(uint64_t) - (tmp_salt - (char *) 0) % __alignof__(uint64_t), salt, salt_len);
+		salt = copied_salt = memcpy(tmp_salt + __alignof__(uint64_t) - (uintptr_t)tmp_salt % __alignof__(uint64_t), salt, salt_len);
 		copied_salt[salt_len] = 0;
 	}