diff --git a/src/port/pg_utf8_fallback.c b/src/port/pg_utf8_fallback.c
index 25e3031b48..0505feffc5 100644
--- a/src/port/pg_utf8_fallback.c
+++ b/src/port/pg_utf8_fallback.c
@@ -29,7 +29,7 @@
  * With six bits per state, the mask is 63, whose importance is described
  * later.
  */
-#define DFA_BITS_PER_STATE 6
+#define DFA_BITS_PER_STATE 5
 #define DFA_MASK ((1 << DFA_BITS_PER_STATE) - 1)
 
 
@@ -82,19 +82,19 @@
  */
 
 /* Invalid state */
-#define	ERR  UINT64CONST(0)
+#define	ERR 0
 /* Begin */
-#define	BGN (UINT64CONST(1) * DFA_BITS_PER_STATE)
+#define	BGN 11
 /* Continuation states */
-#define	CS1 (UINT64CONST(2) * DFA_BITS_PER_STATE)	/* expect 1 cont. byte */
-#define	CS2 (UINT64CONST(3) * DFA_BITS_PER_STATE)	/* expect 2 cont. bytes */
-#define	CS3 (UINT64CONST(4) * DFA_BITS_PER_STATE)	/* expect 3 cont. bytes */
+#define	CS1 16	/* expect 1 cont. byte */
+#define	CS2  1	/* expect 2 cont. bytes */
+#define	CS3  5	/* expect 3 cont. bytes */
 /* Partial 3-byte sequence states, expect 1 more cont. byte */
-#define	P3A (UINT64CONST(5) * DFA_BITS_PER_STATE)	/* leading byte was E0 */
-#define	P3B (UINT64CONST(6) * DFA_BITS_PER_STATE)	/* leading byte was ED */
+#define	P3A  6	/* leading byte was E0 */
+#define	P3B 20	/* leading byte was ED */
 /* Partial 4-byte sequence states, expect 2 more cont. bytes */
-#define	P4A (UINT64CONST(7) * DFA_BITS_PER_STATE)	/* leading byte was F0 */
-#define	P4B (UINT64CONST(8) * DFA_BITS_PER_STATE)	/* leading byte was F4 */
+#define	P4A 25	/* leading byte was F0 */
+#define	P4B 30	/* leading byte was F4 */
 /* Begin and End are the same state */
 #define	END BGN
 
@@ -123,7 +123,7 @@
 #define L4C (P4B << BGN)
 
 /* map an input byte to its byte category */
-const uint64 ByteCategory[256] =
+const uint32 ByteCategory[256] =
 {
 	/* ASCII */
 
@@ -181,7 +181,7 @@ const uint64 ByteCategory[256] =
 };
 
 static inline void
-utf8_advance(const unsigned char *s, uint64 *state, int len)
+utf8_advance(const unsigned char *s, uint32 *state, int len)
 {
 	/* Note: We deliberately don't check the state within the loop. */
 	while (len > 0)
@@ -216,7 +216,7 @@ int
 pg_validate_utf8_fallback(const unsigned char *s, int len)
 {
 	const int	orig_len = len;
-	uint64		state = BGN;
+	uint32		state = BGN;
 
 	while (len >= STRIDE_LENGTH)
 	{