diff --git a/src/port/pg_crc32c_armv8.c b/src/port/pg_crc32c_armv8.c
index 5fa57fb4927..682e8a1ca5d 100644
--- a/src/port/pg_crc32c_armv8.c
+++ b/src/port/pg_crc32c_armv8.c
@@ -127,19 +127,28 @@ pg_comp_crc32c_pmull(pg_crc32c crc, const void *data, size_t len)
 	pg_crc32c	crc0 = crc;
 	const char *buf = data;
 
+	/*
+	 * Immediately fall back to scalar path if the vector path is not
+	 * guaranteed to perform at least one iteration after the alignment
+	 * preamble.
+	 */
+	if (len < 5 * sizeof(uint64x2_t))
+		return pg_comp_crc32c_armv8(crc, data, len);
+
 	/* align to 16 bytes */
-	for (; len && ((uintptr_t) buf & 7); --len)
+	for (; (uintptr_t) buf & 7; --len)
 	{
 		crc0 = __crc32cb(crc0, *buf++);
 	}
-	if (((uintptr_t) buf & 8) && len >= 8)
+	if ((uintptr_t) buf & 8)
 	{
 		crc0 = __crc32cd(crc0, *(const uint64_t *) buf);
 		buf += 8;
 		len -= 8;
 	}
 
-	if (len >= 64)
+	Assert(len >= 64);
+
 	{
 		const char *end = buf + len;
 		const char *limit = buf + len - 64;