From 4f94dad8ae0811bd0da6ff6c05c6e17e5049d5c1 Mon Sep 17 00:00:00 2001
From: Henning Baldersheim <balder@yahoo-inc.com>
Date: Fri, 24 Jan 2020 11:16:18 +0000
Subject: Unroll tight loop.

---
 searchlib/src/vespa/searchlib/common/bitvector.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

(limited to 'searchlib')

diff --git a/searchlib/src/vespa/searchlib/common/bitvector.cpp b/searchlib/src/vespa/searchlib/common/bitvector.cpp
index 7296842f2c1..bd6e677f8d4 100644
--- a/searchlib/src/vespa/searchlib/common/bitvector.cpp
+++ b/searchlib/src/vespa/searchlib/common/bitvector.cpp
@@ -139,7 +139,14 @@ BitVector::Index
 BitVector::internalCount(const Word *tarr, size_t sz)
 {
     Index count(0);
-    for (size_t i(0); i < sz; i++) {
+    size_t i(0);
+    for (; (i + 3) < sz; i += 4) {
+        count += Optimized::popCount(tarr[i + 0]) +
+                 Optimized::popCount(tarr[i + 1]) +
+                 Optimized::popCount(tarr[i + 2]) +
+                 Optimized::popCount(tarr[i + 3]);
+    }
+    for (; i < sz; i++) {
         count += Optimized::popCount(tarr[i]);
     }
     return count;
-- 
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