diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
index a8609e8f78..1e7a176c60 100644
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -169,9 +169,10 @@ struct NumericData
  * otherwise, we want the long one.  Instead of testing against each value, we
  * can just look at the high bit, for a slight efficiency gain.
  */
+#define NUMERIC_HEADER_IS_SHORT(n)	(((n)->choice.n_header & 0x8000) != 0)
 #define NUMERIC_HEADER_SIZE(n) \
 	(VARHDRSZ + sizeof(uint16) + \
-		(((NUMERIC_FLAGBITS(n) & 0x8000) == 0) ? sizeof(int16) : 0))
+	 (NUMERIC_HEADER_IS_SHORT(n) ? 0 : sizeof(int16)))
 
 /*
  * Short format definitions.
@@ -197,11 +198,11 @@ struct NumericData
 	(NUMERIC_IS_SHORT(n) ? \
 		(((n)->choice.n_short.n_header & NUMERIC_SHORT_SIGN_MASK) ? \
 		NUMERIC_NEG : NUMERIC_POS) : NUMERIC_FLAGBITS(n))
-#define NUMERIC_DSCALE(n)	(NUMERIC_IS_SHORT((n)) ? \
+#define NUMERIC_DSCALE(n)	(NUMERIC_HEADER_IS_SHORT((n)) ? \
 	((n)->choice.n_short.n_header & NUMERIC_SHORT_DSCALE_MASK) \
 		>> NUMERIC_SHORT_DSCALE_SHIFT \
 	: ((n)->choice.n_long.n_sign_dscale & NUMERIC_DSCALE_MASK))
-#define NUMERIC_WEIGHT(n)	(NUMERIC_IS_SHORT((n)) ? \
+#define NUMERIC_WEIGHT(n)	(NUMERIC_HEADER_IS_SHORT((n)) ? \
 	(((n)->choice.n_short.n_header & NUMERIC_SHORT_WEIGHT_SIGN_MASK ? \
 		~NUMERIC_SHORT_WEIGHT_MASK : 0) \
 	 | ((n)->choice.n_short.n_header & NUMERIC_SHORT_WEIGHT_MASK)) \
@@ -374,7 +375,7 @@ static void dump_var(const char *str, NumericVar *var);
 
 #define init_var(v)		MemSetAligned(v, 0, sizeof(NumericVar))
 
-#define NUMERIC_DIGITS(num) (NUMERIC_IS_SHORT(num) ? \
+#define NUMERIC_DIGITS(num) (NUMERIC_HEADER_IS_SHORT(num) ? \
 	(num)->choice.n_short.n_data : (num)->choice.n_long.n_data)
 #define NUMERIC_NDIGITS(num) \
 	((VARSIZE(num) - NUMERIC_HEADER_SIZE(num)) / sizeof(NumericDigit))