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From: Alexander Monakov <amonakov@ispras.ru>
To: musl@lists.openwall.com
Cc: Alexander Monakov <amonakov@ispras.ru>
Subject: [PATCH 5/5] dynlink.c: use a faster expression in gnu_hash
Date: Wed, 24 Jun 2015 02:24:55 +0300	[thread overview]
Message-ID: <1435101895-18240-6-git-send-email-amonakov@ispras.ru> (raw)
In-Reply-To: <1435101895-18240-1-git-send-email-amonakov@ispras.ru>

With -Os, GCC uses a multiply rather than a shift and addition for 'h*33'.
Use a more efficient expression explicitely.
---
 src/ldso/dynlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 99be7d0..f7342cd 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -217,7 +217,7 @@ static uint32_t gnu_hash(const char *s0)
 	const unsigned char *s = (void *)s0;
 	uint_fast32_t h = 5381;
 	for (; *s; s++)
-		h = h*33 + *s;
+		h += h*32 + *s;
 	return h;
 }
 


  parent reply	other threads:[~2015-06-23 23:24 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-23 23:24 [PATCH 0/5] gnu-hash speedups Alexander Monakov
2015-06-23 23:24 ` [PATCH 1/5] dynlink.c: use bloom filter in gnu hash lookup Alexander Monakov
2015-06-24  5:39   ` Rich Felker
2015-06-24  6:29     ` Alexander Monakov
2015-06-24  6:32       ` Alexander Monakov
2015-06-24  6:50       ` Rich Felker
2015-06-23 23:24 ` [PATCH 2/5] dynlink.c: compute modulus via magic multiplication Alexander Monakov
2015-06-24  4:18   ` Alexander Monakov
2015-06-24  4:19     ` Rich Felker
2015-06-24  4:24   ` Rich Felker
2015-06-24  4:32     ` Alexander Monakov
2015-06-24  5:13       ` Rich Felker
2015-06-24  6:08         ` Alexander Monakov
2015-06-24  6:39           ` Rich Felker
2015-06-23 23:24 ` [PATCH 3/5] dynlink.c: slim down gnu_lookup Alexander Monakov
2015-06-23 23:24 ` [PATCH 4/5] dynlink.c: pass gnu-hash table pointer to gnu_lookup Alexander Monakov
2015-06-23 23:24 ` Alexander Monakov [this message]
2015-06-27 23:48 ` [PATCH v2 0/6] gnu-hash speedups Alexander Monakov
2015-06-27 23:48   ` [PATCH v2 1/6] dynlink.c: use a faster expression in gnu_hash Alexander Monakov
2015-06-27 23:48   ` [PATCH v2 2/6] dynlink.c: use bloom filter in gnu hash lookup Alexander Monakov
2015-06-27 23:48   ` [PATCH v2 3/6] dynlink.c: slim down gnu_lookup Alexander Monakov
2015-06-27 23:48   ` [PATCH v2 4/6] dynlink.c: pass gnu-hash table pointer to gnu_lookup Alexander Monakov
2015-06-28  0:05     ` Alexander Monakov
2015-06-28  8:59       ` Alexander Monakov
2015-06-27 23:48   ` [PATCH v2 5/6] dynlink.c: compute modulus via magic multiplication Alexander Monakov
2015-06-30 17:51     ` Rich Felker
2015-06-27 23:48   ` [PATCH v2 6/6] dynlink.c: store bloom filter size in struct dso Alexander Monakov
2015-06-28  2:45   ` [PATCH v2 0/6] gnu-hash speedups Rich Felker

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