From e07a2a0f18398a9d55b8b2580ccfd5bc1f18725b Mon Sep 17 00:00:00 2001
From: Alyssa Rosenzweig <a@rosenzweig.io>
Date: Sun, 2 May 2021 13:16:17 -0400
Subject: [PATCH] util/bitset: Add BITSET_COUNT helper

Expressible as a prefix sum but that's a bit unnatural, so add a
convenience helper.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Mike Blumenkrants <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10581>
---
 src/util/bitset.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/util/bitset.h b/src/util/bitset.h
index b9e968293b1..4807709edb3 100644
--- a/src/util/bitset.h
+++ b/src/util/bitset.h
@@ -96,9 +96,23 @@ __bitset_prefix_sum(const BITSET_WORD *x, unsigned b, unsigned n)
    return prefix;
 }
 
+/* Count set bits in the bitset (compute the size/cardinality of the bitset).
+ * This is a special case of prefix sum, but this convenience method is more
+ * natural when applicable.
+ */
+
+static inline unsigned
+__bitset_count(const BITSET_WORD *x, unsigned n)
+{
+   return __bitset_prefix_sum(x, ~0, n);
+}
+
 #define BITSET_PREFIX_SUM(x, b) \
    __bitset_prefix_sum(x, b, ARRAY_SIZE(x))
 
+#define BITSET_COUNT(x) \
+   __bitset_count(x, ARRAY_SIZE(x))
+
 /* Get first bit set in a bitset.
  */
 static inline int