From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by sourceware.org (Postfix) with ESMTPS id A8FB83858010 for ; Wed, 18 Aug 2021 07:15:50 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org A8FB83858010 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 936282203F; Wed, 18 Aug 2021 07:15:49 +0000 (UTC) Received: from murzim.suse.de (murzim.suse.de [10.160.4.192]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 89597A3B91; Wed, 18 Aug 2021 07:15:49 +0000 (UTC) Date: Wed, 18 Aug 2021 09:15:49 +0200 (CEST) From: Richard Biener To: Qing Zhao cc: Jakub Jelinek , Nick Alcock via Gcc-patches , Kees Cook Subject: Re: [patch][version 6] add -ftrivial-auto-var-init and variable attribute "uninitialized" to gcc In-Reply-To: <986D883E-A346-456A-B335-4185D4B136B5@oracle.com> Message-ID: References: <52E29277-1403-4755-901A-528116C43FB8@oracle.com> <517EA40B-9500-4090-8F03-B4A9CECC62F8@oracle.com> <8B2F93E8-C3AC-49D2-B764-D4DD8A150A52@oracle.com> <786F370D-4A45-4F66-846C-A3437A162A65@oracle.com> <986D883E-A346-456A-B335-4185D4B136B5@oracle.com> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 X-Spam-Status: No, score=-4.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, 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 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 8BIT X-Content-Filtered-By: Mailman/MimeDel 2.1.29 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, 18 Aug 2021 07:16:01 -0000 On Tue, 17 Aug 2021, Qing Zhao wrote: > > > > On Aug 17, 2021, at 9:50 AM, Qing Zhao via Gcc-patches wrote: > > > > > > > >> On Aug 17, 2021, at 3:29 AM, Richard Biener wrote: > >> > >> On Mon, 16 Aug 2021, Qing Zhao wrote: > >> > >>> My current code for expand_DEFERRED_INIT is like the following, could you check and see whether there is any issue for it: > >>> > >>> #define INIT_PATTERN_VALUE 0xFE > >>> static void > >>> expand_DEFERRED_INIT (internal_fn, gcall *stmt) > >>> { > >>> tree lhs = gimple_call_lhs (stmt); > >>> tree var_size = gimple_call_arg (stmt, 0); > >>> enum auto_init_type init_type > >>> = (enum auto_init_type) TREE_INT_CST_LOW (gimple_call_arg (stmt, 1)); > >>> bool is_vla = (bool) TREE_INT_CST_LOW (gimple_call_arg (stmt, 2)); > >>> > >>> tree var_type = TREE_TYPE (lhs); > >>> gcc_assert (init_type > AUTO_INIT_UNINITIALIZED); > >>> > >>> if (is_vla || (!use_register_for_decl (lhs))) > >>> { > >>> if (TREE_CODE (lhs) == SSA_NAME) > >>> lhs = SSA_NAME_VAR (lhs); > >> > >> this should not be necessary (in fact you shouldn't see a SSA_NAME > >> here, if you do then using SSA_NAME_VAR is wrong) > > You mean during RTL expansion phase, all SSA_NAMEs are gone already? > > Actually, the lhs could be SSA_NAME here, > > Breakpoint 1, expand_DEFERRED_INIT (stmt=0x7fffe96ae348) at ../../latest-gcc/gcc/internal-fn.c:3021 > 3021 mark_addressable (lhs); > (gdb) call debug_tree(lhs) > type size > unit-size > align:32 warn_if_not_align:0 symtab:0 alias-set 2 canonical-type 0x7fffe959b2a0 precision:32 > pointer_to_this > > visited var > def_stmt temp1_5 = .DEFERRED_INIT (4, 2, 0, &"temp1"[0]); > version:5> > > when I deleted: > > if (TREE_CODE (lhs) == SSA_NAME > lhs = SSA_NAME_VAR (lhs); but then using SSA_NAME_VAR is broken. I suspect use_register_for_decl isn't the correct thing to look at. I think we need to look at what the LHS expanded to if it is a SSA_VAR_P (that includes SSA names but also plain DECLs but not what we get from VLAs where we'd see *ptr). So sth like bool reg_lhs; if (SSA_VAR_P (lhs)) { rtx tem = expand_expr (lhs, NULL_RTX, VOIDmode, EXPAND_WRITE); reg_lhs = !MEM_P (tem); /* If not MEM_P reg_lhs should be REG_P or SUBREG_P (but maybe also CONCAT or lowpart...?) */ } else { gcc_assert (is_vla); reg_lhs = false; } if (!reg_lhs) memset path else expand_assignment path > Many testing cases failed with internal compiler error: > > /home/opc/Work/GCC/latest-gcc/gcc/testsuite/c-c++-common/auto-init-3.c:9:9: internal compiler error: in expand_expr_addr_expr_1, at expr.c:8437 > 0xe237aa expand_expr_addr_expr_1 > ../../latest-gcc/gcc/expr.c:8437 > 0xe24059 expand_expr_addr_expr > ../../latest-gcc/gcc/expr.c:8525 > 0xe32b56 expand_expr_real_1(tree_node*, rtx_def*, machine_mode, expand_modifier, rtx_def**, bool) > ../../latest-gcc/gcc/expr.c:11741 > 0xe2da52 expand_expr_real_1(tree_node*, rtx_def*, machine_mode, expand_modifier, rtx_def**, bool) > ../../latest-gcc/gcc/expr.c:10777 > 0xe24706 expand_expr_real(tree_node*, rtx_def*, machine_mode, expand_modifier, rtx_def**, bool) > ../../latest-gcc/gcc/expr.c:8713 > 0xc13f15 expand_expr > ../../latest-gcc/gcc/expr.h:301 > 0xc17acb get_memory_rtx > ../../latest-gcc/gcc/builtins.c:1370 > 0xc2223d expand_builtin_memset_args > ../../latest-gcc/gcc/builtins.c:4102 > 0xc21a20 expand_builtin_memset(tree_node*, rtx_def*, machine_mode) > ../../latest-gcc/gcc/builtins.c:3886 > 0xfb5c85 expand_DEFERRED_INIT > ../../latest-gcc/gcc/internal-fn.c:3031 > > > So, did I do anything wrong? > > Qing -- Richard Biener SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)