From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751920AbaK1QBs (ORCPT ); Fri, 28 Nov 2014 11:01:48 -0500 Received: from mail-lb0-f176.google.com ([209.85.217.176]:41163 "EHLO mail-lb0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751408AbaK1QBq (ORCPT ); Fri, 28 Nov 2014 11:01:46 -0500 From: Rasmus Villemoes To: Andrew Morton , Jan Kara Cc: linux-kernel@vger.kernel.org Subject: [PATCH 2/7] lib: bitmap: Eliminate branch in __bitmap_shift_right Date: Fri, 28 Nov 2014 17:01:05 +0100 Message-Id: <1417190476-18066-3-git-send-email-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.0.4 In-Reply-To: <1417190476-18066-1-git-send-email-linux@rasmusvillemoes.dk> References: <1417190476-18066-1-git-send-email-linux@rasmusvillemoes.dk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We can shift the bits from lower and upper into place before assembling dst[k]; moving the shift of upper into the branch where we already know that rem is non-zero allows us to remove a conditional. Signed-off-by: Rasmus Villemoes --- lib/bitmap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index 2332115..9250c3f 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -127,13 +127,13 @@ void __bitmap_shift_right(unsigned long *dst, const unsigned long *src, upper = src[off + k + 1]; if (off + k + 1 == lim - 1 && left) upper &= mask; + upper <<= (BITS_PER_LONG - rem); } lower = src[off + k]; if (left && off + k == lim - 1) lower &= mask; - dst[k] = lower >> rem; - if (rem) - dst[k] |= upper << (BITS_PER_LONG - rem); + lower >>= rem; + dst[k] = lower | upper; if (left && k == lim - 1) dst[k] &= mask; } -- 2.0.4