Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933287AbaLDXAy (ORCPT ); Thu, 4 Dec 2014 18:00:54 -0500 Received: from smtprelay0160.hostedemail.com ([216.40.44.160]:55325 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754776AbaLDXAx (ORCPT ); Thu, 4 Dec 2014 18:00:53 -0500 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,joe@perches.com,:::::::::::::::::::::::::,RULES_HIT:41:355:379:541:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1373:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2198:2199:2393:2553:2559:2562:2828:3138:3139:3140:3141:3142:3352:3865:3867:4321:4605:5007:6119:6261:6690:6742:7903:8603:10004:10400:10848:11026:11658:11914:12043:12296:12517:12519:12555:13069:13161:13229:13311:13357:13972:14394:21080,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0 X-HE-Tag: toy38_7364478c500f X-Filterd-Recvd-Size: 2881 Message-ID: <1417734048.2721.22.camel@perches.com> Subject: [PATCH] x86: bpf_jit_comp: Reduce is_ereg() code size From: Joe Perches To: Alexei Starovoitov Cc: Quentin Lambert , "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" Date: Thu, 04 Dec 2014 15:00:48 -0800 In-Reply-To: References: Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: Evolution 3.12.7-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use the (1 << reg) & mask trick to reduce code size. x86-64 size difference -O2 without profiling for various gcc versions: $ size arch/x86/net/bpf_jit_comp.o* text data bss dec hex filename 9266 4 0 9270 2436 arch/x86/net/bpf_jit_comp.o.4.4.new 10042 4 0 10046 273e arch/x86/net/bpf_jit_comp.o.4.4.old 9109 4 0 9113 2399 arch/x86/net/bpf_jit_comp.o.4.6.new 9717 4 0 9721 25f9 arch/x86/net/bpf_jit_comp.o.4.6.old 8789 4 0 8793 2259 arch/x86/net/bpf_jit_comp.o.4.7.new 10245 4 0 10249 2809 arch/x86/net/bpf_jit_comp.o.4.7.old 9671 4 0 9675 25cb arch/x86/net/bpf_jit_comp.o.4.9.new 10679 4 0 10683 29bb arch/x86/net/bpf_jit_comp.o.4.9.old Signed-off-by: Joe Perches --- compiled, untested by me, but per Alexei Starovoitov this passes the test_bpf suite diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 3f62734..09e2cea 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -135,11 +135,11 @@ static const int reg2hex[] = { */ static inline bool is_ereg(u32 reg) { - if (reg == BPF_REG_5 || reg == AUX_REG || - (reg >= BPF_REG_7 && reg <= BPF_REG_9)) - return true; - else - return false; + return (1 << reg) & (BIT(BPF_REG_5) | + BIT(AUX_REG) | + BIT(BPF_REG_7) | + BIT(BPF_REG_8) | + BIT(BPF_REG_9)); } /* add modifiers if 'reg' maps to x64 registers r8..r15 */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/