From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 50556 invoked by alias); 20 May 2015 13:02:44 -0000 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 Received: (qmail 50546 invoked by uid 89); 20 May 2015 13:02:43 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.4 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-ie0-f179.google.com Received: from mail-ie0-f179.google.com (HELO mail-ie0-f179.google.com) (209.85.223.179) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Wed, 20 May 2015 13:02:42 +0000 Received: by ieczm2 with SMTP id zm2so38331966iec.1 for ; Wed, 20 May 2015 06:02:40 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.50.79.196 with SMTP id l4mr28307819igx.48.1432126960411; Wed, 20 May 2015 06:02:40 -0700 (PDT) Received: by 10.36.108.21 with HTTP; Wed, 20 May 2015 06:02:40 -0700 (PDT) In-Reply-To: <20150520010937.GD6140@bubble.grove.modra.org> References: <20150518025234.GT6140@bubble.grove.modra.org> <20150518025407.GU6140@bubble.grove.modra.org> <20150520010937.GD6140@bubble.grove.modra.org> Date: Wed, 20 May 2015 13:07:00 -0000 Message-ID: Subject: Re: [PATCH 1/4] rs6000_stack_info changes for -fsplit-stack From: David Edelsohn To: GCC Patches , Alan Modra Content-Type: text/plain; charset=ISO-8859-1 X-SW-Source: 2015-05/txt/msg01827.txt.bz2 On Tue, May 19, 2015 at 9:09 PM, Alan Modra wrote: > On Mon, May 18, 2015 at 02:05:59PM -0400, David Edelsohn wrote: >> On Sun, May 17, 2015 at 10:54 PM, Alan Modra wrote: >> > This patch changes rs6000_stack_info to keep save areas offsets even >> > when not used. I need lr_save_offset valid for split-stack, and it >> > seemed reasonable to treat the other offsets the same. Not zeroing >> > the offsets requires just one change in code that uses them, the >> > use_backchain_to_restore_sp expression in rs6000_emit_epilogue, not >> > counting the debug_stack_info changes. >> > >> > * config/rs6000/rs6000.c (rs6000_stack_info): Don't zero offsets >> > when not saving registers. >> > (debug_stack_info): Adjust to omit printing unused offsets, >> > as before. >> > (rs6000_emit_epilogue): Adjust use_backchain_to_restore_sp >> > expression. >> >> I think that the vrsave_save_offset change may break saving of >> callee-saved VRs. See PR 55276. > > I checked. It doesn't break that testcase. PR 55276 was really > caused by using vrsave_mask for two purposes, firstly to track which > altivec registers have been saved, and secondly to control use of the > vrsave stack slot and whether mfvrsave/mtvrsave insns are generated. > Patch 2/4 removes this conflation. Okay, but that confirms Patch 1 is not safe without the patch series. - David