From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754611AbaFSNQE (ORCPT ); Thu, 19 Jun 2014 09:16:04 -0400 Received: from mail-la0-f45.google.com ([209.85.215.45]:58070 "EHLO mail-la0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752695AbaFSNQB (ORCPT ); Thu, 19 Jun 2014 09:16:01 -0400 From: Rasmus Villemoes To: Peter Zijlstra , "H. Peter Anvin" , Ingo Molnar Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Rasmus Villemoes Subject: [PATCH] x86: Micro-optimization in nhmex_rbox_get_constraint Date: Thu, 19 Jun 2014 15:15:31 +0200 Message-Id: <1403183731-15402-1-git-send-email-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 1.7.10.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Flipping the LSB doesn't require four lines of code. This shaves a few bytes of the generated code, including a branch. Signed-off-by: Rasmus Villemoes --- arch/x86/kernel/cpu/perf_event_intel_uncore.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c index 65bbbea..e009f3c 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c @@ -2946,10 +2946,7 @@ again: * extra registers. If we failed to take an extra * register, try the alternative. */ - if (idx % 2) - idx--; - else - idx++; + idx ^= 1; if (idx != reg1->idx % 6) { if (idx == 2) config1 >>= 8; -- 1.9.2