From 9c3451fdca9598772572f59bb594245e1c78137e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Fri, 26 Oct 2012 18:11:31 +0200
Subject: erts: Use memcpy instead of while in setelement/3

* Measurements suggests that memcpy is a bit faster for small tuples
  and ~50% faster for large tuples. (Linux kernel-3.2.0).
---
 erts/emulator/beam/bif.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

(limited to 'erts')

diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index 6d94632971..089d311830 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -2428,9 +2428,7 @@ BIF_RETTYPE setelement_3(BIF_ALIST_3)
 
     /* copy the tuple */
     resp = hp;
-    while (size--) {		/* XXX use memcpy? */
-	*hp++ = *ptr++;
-    }
+    sys_memcpy(hp, ptr, sizeof(Eterm)*size);
     resp[ix] = BIF_ARG_3;
     BIF_RET(make_tuple(resp));
 }
-- 
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