From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15158 invoked by alias); 5 Sep 2012 22:47:41 -0000 Received: (qmail 15086 invoked by uid 22791); 5 Sep 2012 22:47:40 -0000 X-SWARE-Spam-Status: No, hits=-2.9 required=5.0 tests=AWL,BAYES_00,KHOP_THREADED,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from dns1.mips.com (HELO dns1.mips.com) (12.201.5.69) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 05 Sep 2012 22:47:17 +0000 Received: from mailgate1.mips.com (mailgate1.mips.com [12.201.5.111]) by dns1.mips.com (8.13.8/8.13.8) with ESMTP id q85MlFsr021170; Wed, 5 Sep 2012 15:47:15 -0700 X-M-MSG: Received: from exchdb01.mips.com (unknown [192.168.36.84]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by mailgate1.mips.com (Postfix) with ESMTP id 20781364669; Wed, 5 Sep 2012 15:47:11 -0700 (PDT) Received: from [192.168.65.53] (192.168.65.53) by exchhub01.mips.com (192.168.36.84) with Microsoft SMTP Server id 14.1.270.1; Wed, 5 Sep 2012 15:47:09 -0700 Subject: Re: [Patch, PR 54128] ira.c change to fix mips bootstrap From: Steve Ellcey To: Jakub Jelinek CC: In-Reply-To: <20120905061507.GD1999@tucnak.redhat.com> References: <20120905061507.GD1999@tucnak.redhat.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 05 Sep 2012 22:47:00 -0000 Message-ID: <1346885229.14333.145.camel@ubuntu-sellcey> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-EMS-Proccessed: 6LP3oGfGVdcdb8o1aBnt6w== X-EMS-STAMP: hI0EY+JuaOkc5j3rB2Fxcw== Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2012-09/txt/msg00334.txt.bz2 On Wed, 2012-09-05 at 08:15 +0200, Jakub Jelinek wrote: > The debug insns generally shouldn't extend the lifetime of pseudos (see the > valtrack.c stuff), so if you hit this, there is probably some earlier bug > that didn't reset/adjust the debug insns in question. > I'm not saying the ira.c patch is absolutely a bad idea, but it would be > good if you could investigate where those debug insns started extending > lifetime of pseudos. I am not sure I know how to do that. I am also not sure the problem is with extending the life of a psuedo register or if it is in recognizing that a hard register is dead. $2, the register that doesn't get reused when generating debug code is the register used to return values. In this case I am returning a 64 bit integer value (step_c) that is split across two registers ($2 and $3). In the ira dump file I don't see any debug instructions referring to $3, but I do have one for $2. The debug_insn for $2 first shows up in the cse1 phase and there is no debug_insn for $3, perhaps because we only use the lower half of the return value. (debug_insn 73 25 72 5 (var_location:SI D#1 (reg:SI 2 $2)) -1 (nil)) (insn 72 73 27 5 (set (reg:SI 224 [ step_c+4 ]) (reg:SI 3 $3 [orig:2+4 ] [2])) x.i:58 282 {*movsi_internal} (expr_list:REG_DEAD (reg:SI 3 $3 [orig:2+4 ] [2]) (nil))) (debug_insn 27 72 28 5 (var_location:DI step_c (concatn/v:DI [ (debug_expr:SI D#1) (reg:SI 224 [ step_c+4 ]) ])) x.i:58 -1 (nil)) It seems odd to have a concatn where one element is a debug_expr and the other is a register. But I don't know if this is a problem or a normal way of handling functions that return a value in two registers. Steve Ellcey sje@cup.hp.com