postgres.git / summary / log / commit / refs

commit    f33b8793fd7306b81e8c614718ee8f01b4fa0cfd
Author:   Nathan Bossart <nathan@postgresql.org>
Date:     Mon Feb 23 15:26:00 2026 +0000

    Make use of pg_popcount() in more places.
    
    This replaces some loops over word-length popcount functions with
    calls to pg_popcount().  Since pg_popcount() may use a function
    pointer for inputs with sizes >= a Bitmapset word, this produces a
    small regression for the common one-word case in bms_num_members().
    To deal with that, this commit adds an inlined fast-path for that
    case.  This fast-path could arguably go in pg_popcount() itself
    (with an appropriate alignment check), but that is left for future
    study.
    
    Suggested-by: John Naylor <johncnaylorls@gmail.com>
    Reviewed-by: John Naylor <johncnaylorls@gmail.com>
    Discussion: https://postgr.es/m/CANWCAZY7R%2Biy%2Br9YM_sySNydHzNqUirx1xk0tB3ej5HO62GdgQ%40mail.gmail.com


 src/backend/nodes/bitmapset.c | 29 +++++++----------------------
 src/include/lib/radixtree.h   |  6 +++---
 2 files changed, 10 insertions(+), 25 deletions(-)

diff --git a/src/backend/nodes/bitmapset.c b/src/backend/nodes/bitmapset.c
index a4765876c31..786f343b3c9 100644
--- a/src/backend/nodes/bitmapset.c
+++ b/src/backend/nodes/bitmapset.c
@@ -553,14 +553,8 @@ bms_member_index(Bitmapset *a, int x)
 	bitnum = BITNUM(x);
 
 	/* count bits in preceding words */
-	for (int i = 0; i < wordnum; i++)
-	{
-		bitmapword	w = a->words[i];
-
-		/* No need to count the bits in a zero word */
-		if (w != 0)
-			result += bmw_popcount(w);
-	}
+	result += pg_popcount((const char *) a->words,
+						  wordnum * sizeof(bitmapword));
 
 	/*
 	 * Now add bits of the last word, but only those before the item. We can
@@ -749,26 +743,17 @@ bms_get_singleton_member(const Bitmapset *a, int *member)
 int
 bms_num_members(const Bitmapset *a)
 {
-	int			result = 0;
-	int			nwords;
-	int			wordnum;
-
 	Assert(bms_is_valid_set(a));
 
 	if (a == NULL)
 		return 0;
 
-	nwords = a->nwords;
-	wordnum = 0;
-	do
-	{
-		bitmapword	w = a->words[wordnum];
+	/* fast-path for common case */
+	if (a->nwords == 1)
+		return bmw_popcount(a->words[0]);
 
-		/* No need to count the bits in a zero word */
-		if (w != 0)
-			result += bmw_popcount(w);
-	} while (++wordnum < nwords);
-	return result;
+	return pg_popcount((const char *) a->words,
+					   a->nwords * sizeof(bitmapword));
 }
 
 /*
diff --git a/src/include/lib/radixtree.h b/src/include/lib/radixtree.h
index b223ce10a2d..e6c9a591c17 100644
--- a/src/include/lib/radixtree.h
+++ b/src/include/lib/radixtree.h
@@ -2721,12 +2721,12 @@ RT_VERIFY_NODE(RT_NODE * node)
 		case RT_NODE_KIND_256:
 			{
 				RT_NODE_256 *n256 = (RT_NODE_256 *) node;
-				int			cnt = 0;
+				int			cnt;
 
 				/* RT_DUMP_NODE(node); */
 
-				for (int i = 0; i < RT_BM_IDX(RT_NODE_MAX_SLOTS); i++)
-					cnt += bmw_popcount(n256->isset[i]);
+				cnt = pg_popcount((const char *) n256->isset,
+								  RT_NODE_MAX_SLOTS / BITS_PER_BYTE);
 
 				/*
 				 * Check if the number of used chunk matches, accounting for


[parent: eb9ab7e0930a]