From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-out.m-online.net (mail-out.m-online.net [212.18.0.9]) by sourceware.org (Postfix) with ESMTPS id 538763858415 for ; Wed, 6 Oct 2021 13:15:53 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 538763858415 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=linux-m68k.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=nefkom.net Received: from frontend02.mail.m-online.net (unknown [192.168.8.183]) by mail-out.m-online.net (Postfix) with ESMTP id 4HPZhS1jXRz1qwy6; Wed, 6 Oct 2021 15:15:52 +0200 (CEST) Received: from localhost (dynscan2.mnet-online.de [192.168.6.68]) by mail.m-online.net (Postfix) with ESMTP id 4HPZhR6yFRz1qqkD; Wed, 6 Oct 2021 15:15:51 +0200 (CEST) X-Virus-Scanned: amavisd-new at mnet-online.de Received: from mail.mnet-online.de ([192.168.8.182]) by localhost (dynscan2.mail.m-online.net [192.168.6.68]) (amavisd-new, port 10024) with ESMTP id WW8D23PRIpOz; Wed, 6 Oct 2021 15:15:51 +0200 (CEST) X-Auth-Info: FK7sjHbEVTBhDxJIE80XsgJbSH5NEQoiqFCX3oHW8XAty51k83kDEaCPkGQr/4ae Received: from igel.home (ppp-46-244-184-42.dynamic.mnet-online.de [46.244.184.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mnet-online.de (Postfix) with ESMTPSA; Wed, 6 Oct 2021 15:15:51 +0200 (CEST) Received: by igel.home (Postfix, from userid 1000) id 8795F2C2518; Wed, 6 Oct 2021 15:15:50 +0200 (CEST) From: Andreas Schwab To: Aldy Hernandez via Gcc-patches Cc: Michael Matz , Aldy Hernandez Subject: Re: [RFC] More jump threading restrictions in the presence of loops. References: <20211004094313.1596556-1-aldyh@redhat.com> X-Yow: You should all JUMP UP AND DOWN for TWO HOURS while I decide on a NEW CAREER!! Date: Wed, 06 Oct 2021 15:15:50 +0200 In-Reply-To: (Aldy Hernandez via Gcc-patches's message of "Tue, 5 Oct 2021 15:33:48 +0200") Message-ID: <87ilyab8ft.fsf@igel.home> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, KAM_DMARC_STATUS, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Oct 2021 13:15:56 -0000 On Okt 05 2021, Aldy Hernandez via Gcc-patches wrote: > From 5abe65668f602d53b8f3dc515508dc4616beb048 Mon Sep 17 00:00:00 2001 > From: Aldy Hernandez > Date: Tue, 5 Oct 2021 15:03:34 +0200 > Subject: [PATCH] Loosen loop crossing restriction in threader. > > Crossing loops is generally discouraged from the threader, but we can > make an exception when we don't cross the latch or enter another loop, > since this is just an early exit out of the loop. This breaks bootstrap on aarch64 (in stage2): In function 'void mark_stack_region_used(poly_uint64, poly_uint64)', inlined from 'rtx_def* emit_library_call_value_1(int, rtx, rtx, libcall_type, machine_mode, int, rtx_mode_t*)' at ../../gcc/calls.c:4536:29: ../../gcc/calls.c:206:26: error: 'const_upper' may be used uninitialized in this function [-Werror=maybe-uninitialized] 206 | stack_usage_map[i] = 1; | ~~~~~~~~~~~~~~~~~~~^~~ ../../gcc/calls.c: In function 'rtx_def* emit_library_call_value_1(int, rtx, rtx, libcall_type, machine_mode, int, rtx_mode_t*)': ../../gcc/calls.c:202:39: note: 'const_upper' was declared here 202 | unsigned HOST_WIDE_INT const_lower, const_upper; | ^~~~~~~~~~~ Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."