diff --git a/src/include/port/pg_bitutils.h b/src/include/port/pg_bitutils.h
index 9150789aaf..39b55f51ec 100644
--- a/src/include/port/pg_bitutils.h
+++ b/src/include/port/pg_bitutils.h
@@ -40,39 +40,30 @@ extern PGDLLIMPORT const uint8 pg_number_of_ones[256];
 static inline int
 pg_leftmost_one_pos32(uint32 word)
 {
-#ifdef HAVE__BUILTIN_CLZ
-	int			bitscan_result;
-#elif defined(_MSC_VER)
-	unsigned long bitscan_result;
+#if defined(_MSC_VER)
+	unsigned long result;
 	bool		non_zero;
-#endif
-
-#if !defined(HAVE_BITSCAN_REVERSE) || defined(USE_ASSERT_CHECKING)
+#else
 	int			result;
-	int			shift = 32 - 8;
+#endif
 
 	Assert(word != 0);
 
+#if defined(HAVE__BUILTIN_CLZ)
+	result = 31 - __builtin_clz(word);
+#elif defined(_MSC_VER)
+	non_zero = _BitScanReverse(&result, word);
+	Assert(non_zero);
+#else
+	int			shift = 32 - 8;
+
 	while ((word >> shift) == 0)
 		shift -= 8;
 
 	result = shift + pg_leftmost_one_pos[(word >> shift) & 255];
 #endif
 
-#ifdef HAVE_BITSCAN_REVERSE
-
-#if defined(HAVE__BUILTIN_CLZ)
-	bitscan_result = 31 - __builtin_clz(word);
-#elif defined(_MSC_VER)
-	non_zero = _BitScanReverse(&bitscan_result, word);
-	Assert(non_zero);
-#endif
-	Assert(bitscan_result == result);
-	return bitscan_result;
-
-#else
 	return result;
-#endif							/* HAVE_BITSCAN_REVERSE */
 }
 
 /*
@@ -82,46 +73,38 @@ pg_leftmost_one_pos32(uint32 word)
 static inline int
 pg_leftmost_one_pos64(uint64 word)
 {
-#ifdef HAVE__BUILTIN_CLZ
-	int			bitscan_result;
-#elif defined(_MSC_VER)
-	unsigned long bitscan_result;
+#if defined(_MSC_VER)
+	unsigned long result;
 	bool		non_zero;
-#endif
-
-#if !defined(HAVE_BITSCAN_REVERSE) || defined(USE_ASSERT_CHECKING)
+#else
 	int			result;
-	int			shift = 64 - 8;
-
-	Assert(word != 0);
-
-	while ((word >> shift) == 0)
-		shift -= 8;
-
-	result = shift + pg_leftmost_one_pos[(word >> shift) & 255];
 #endif
 
-#ifdef HAVE_BITSCAN_REVERSE
+	Assert(word != 0);
 
 #if defined(HAVE__BUILTIN_CLZ)
 #if defined(HAVE_LONG_INT_64)
-	bitscan_result = 63 - __builtin_clzl(word);
+	result = 63 - __builtin_clzl(word);
 #elif defined(HAVE_LONG_LONG_INT_64)
-	bitscan_result = 63 - __builtin_clzll(word);
+	result = 63 - __builtin_clzll(word);
 #else
 #error must have a working 64-bit integer datatype
 #endif							/* HAVE_LONG_INT_64 */
 
 #elif defined(_MSC_VER)
-	non_zero = _BitScanReverse64(&bitscan_result, word);
+	non_zero = _BitScanReverse64(&result, word);
 	Assert(non_zero);
+#else
+	int			result;
+	int			shift = 64 - 8;
+
+	while ((word >> shift) == 0)
+		shift -= 8;
+
+	result = shift + pg_leftmost_one_pos[(word >> shift) & 255];
 #endif							/* HAVE__BUILTIN_CLZ */
-	Assert(bitscan_result == result);
-	return bitscan_result;
 
-#else
 	return result;
-#endif							/* HAVE_BITSCAN_REVERSE */
 }
 
 /*
@@ -132,20 +115,23 @@ pg_leftmost_one_pos64(uint64 word)
 static inline int
 pg_rightmost_one_pos32(uint32 word)
 {
-#ifdef HAVE__BUILTIN_CTZ
-	const uint32 orig_word = word;
-	int			bitscan_result;
-#elif defined(_MSC_VER)
-	const unsigned long orig_word = word;
-	unsigned long bitscan_result;
+#if defined(_MSC_VER)
+	unsigned long result;
 	bool		non_zero;
+#else
+	int			result;
 #endif
 
-#if !defined(HAVE_BITSCAN_FORWARD) || defined(USE_ASSERT_CHECKING)
-	int			result = 0;
-
 	Assert(word != 0);
 
+#if defined(HAVE__BUILTIN_CTZ)
+	result = __builtin_ctz(word);
+#elif defined(_MSC_VER)
+	non_zero = _BitScanForward(&result, word);
+	Assert(non_zero);
+#else
+	result = 0;
+
 	while ((word & 255) == 0)
 	{
 		word >>= 8;
@@ -154,20 +140,7 @@ pg_rightmost_one_pos32(uint32 word)
 	result += pg_rightmost_one_pos[word & 255];
 #endif
 
-#ifdef HAVE_BITSCAN_FORWARD
-
-#if defined(HAVE__BUILTIN_CTZ)
-	bitscan_result = __builtin_ctz(orig_word);
-#elif defined(_MSC_VER)
-	non_zero = _BitScanForward(&bitscan_result, orig_word);
-	Assert(non_zero);
-#endif
-	Assert(bitscan_result == result);
-	return bitscan_result;
-
-#else
 	return result;
-#endif							/* HAVE_BITSCAN_FORWARD */
 }
 
 /*
@@ -177,49 +150,39 @@ pg_rightmost_one_pos32(uint32 word)
 static inline int
 pg_rightmost_one_pos64(uint64 word)
 {
-#ifdef HAVE__BUILTIN_CTZ
-	const uint64 orig_word = word;
-	int			bitscan_result;
-#elif defined(_MSC_VER)
-	const unsigned __int64 orig_word = word;
-	unsigned long bitscan_result;
+#if defined(_MSC_VER)
+	unsigned long result;
 	bool		non_zero;
+#else
+	int			result;
 #endif
 
-#if !defined(HAVE_BITSCAN_FORWARD) || defined(USE_ASSERT_CHECKING)
-	int			result = 0;
-
 	Assert(word != 0);
 
-	while ((word & 255) == 0)
-	{
-		word >>= 8;
-		result += 8;
-	}
-	result += pg_rightmost_one_pos[word & 255];
-#endif
-
-#ifdef HAVE_BITSCAN_FORWARD
-
 #if defined(HAVE__BUILTIN_CTZ)
 #if defined(HAVE_LONG_INT_64)
-	bitscan_result = __builtin_ctzl(orig_word);
+	result = __builtin_ctzl(word);
 #elif defined(HAVE_LONG_LONG_INT_64)
-	bitscan_result = __builtin_ctzll(orig_word);
+	result = __builtin_ctzll(word);
 #else
 #error must have a working 64-bit integer datatype
 #endif							/* HAVE_LONG_INT_64 */
 
 #elif defined(_MSC_VER)
-	non_zero = _BitScanForward64(&bitscan_result, orig_word);
+	non_zero = _BitScanForward64(&result, word);
 	Assert(non_zero);
-#endif							/* HAVE__BUILTIN_CTZ */
-	Assert(bitscan_result == result);
-	return bitscan_result;
-
 #else
+	result = 0;
+
+	while ((word & 255) == 0)
+	{
+		word >>= 8;
+		result += 8;
+	}
+	result += pg_rightmost_one_pos[word & 255];
+#endif
+
 	return result;
-#endif							/* HAVE_BITSCAN_FORWARD */
 }
 
 /*