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[209.132.180.131]) by mx.google.com with ESMTPS id d2si33181053pli.105.2016.12.09.02.20.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 09 Dec 2016 02:20:22 -0800 (PST) Received-SPF: pass (google.com: domain of gcc-patches-return-443879-patch=linaro.org@gcc.gnu.org designates 209.132.180.131 as permitted sender) client-ip=209.132.180.131; Authentication-Results: mx.google.com; dkim=pass header.i=@gcc.gnu.org; spf=pass (google.com: domain of gcc-patches-return-443879-patch=linaro.org@gcc.gnu.org designates 209.132.180.131 as permitted sender) smtp.mailfrom=gcc-patches-return-443879-patch=linaro.org@gcc.gnu.org DomainKey-Signature: a=rsa-sha1; c=nofws; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender :subject:to:references:cc:from:message-id:date:mime-version :in-reply-to:content-type; q=dns; s=default; b=hhC7q+7+6cT+VPG8h 4G0lAHbeUmKcR14d8zOmAB9dBXa6PDeczbjclTVuolzQZcSjX8D1NAhRwnxqLYLf XJaq50PJtDYlmq02JgjSDRCy2OHWzsvPjXZ4FXRlcMm1ofZCe+6k+s3DolnBKobG a6y4pSbNF1r1Ka06hnNH0aQfwg= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=gcc.gnu.org; h=list-id :list-unsubscribe:list-archive:list-post:list-help:sender :subject:to:references:cc:from:message-id:date:mime-version :in-reply-to:content-type; s=default; bh=wfClXCkdofECCNqqRqurO7F kLBY=; b=ygGqIkjvWkBHWcRJOPFh9o1hkGFRg1Sp4RFB++qhZnjxV9xxbq8U18n q8DKaVUZfhH77RiL6HEzy+BKuV25A/M6SMnb8WCxa/Xw3jjrpnQzyzKIGl/CdMLc B9J99WBc9h9NRY+7lcNyIrStIc3hnPN7FNMjf9buZQXc6VNXjWys= Received: (qmail 26027 invoked by alias); 9 Dec 2016 10:20:09 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Delivered-To: mailing list gcc-patches@gcc.gnu.org Received: (qmail 25986 invoked by uid 89); 9 Dec 2016 10:20:07 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00, SPF_PASS autolearn=ham version=3.3.2 spammy=decl_size, tree_to_shwi, DECL_SIZE, H*M:1f69 X-HELO: mx2.suse.de Received: from mx2.suse.de (HELO mx2.suse.de) (195.135.220.15) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 09 Dec 2016 10:19:57 +0000 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 11CFAAAB7; Fri, 9 Dec 2016 10:19:53 +0000 (UTC) Subject: Re: [PATCH] Fill bitregion_{start, end} in store_constructor (PR, tree-optimization/78428). To: Richard Biener , Eric Botcazou References: <22d70b27-ddad-6410-3c59-1e630d3d7d55@suse.cz> Cc: GCC Patches , Jakub Jelinek From: =?UTF-8?Q?Martin_Li=c5=a1ka?= Message-ID: Date: Fri, 9 Dec 2016 11:19:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: X-IsSubscribed: yes On 11/23/2016 11:49 AM, Richard Biener wrote: > On Wed, Nov 23, 2016 at 11:26 AM, Martin Liška wrote: >> Following patch fixes situation where we do a store to a bitfield which >> is at boundary of a record. This leads to usage of wider store, leading >> to overwriting a following memory location. >> >> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests. >> Apart from that, the reported test-case in PR works on x86_64-linux-gnu. >> >> Ready to be installed? > > + HOST_WIDE_INT bitregion_end > + = exp_size == -1 ? 0 : exp_size * BITS_PER_UNIT - 1; > > I don't think looking at the CONSTRUCTOR to determine bitregion_end is > a good idea. > The function gets 'size' as argument which is documented as "number of > bytes we are > allowed to modify" - so better use that. > > @@ -6308,7 +6314,8 @@ store_constructor (tree exp, rtx target, int > cleared, HOST_WIDE_INT size, > MEM_KEEP_ALIAS_SET_P (to_rtx) = 1; > } > > - store_constructor_field (to_rtx, bitsize, bitpos, mode, > + store_constructor_field (to_rtx, bitsize, bitpos, > + 0, bitregion_end, mode, > value, cleared, > get_alias_set (TREE_TYPE (field)), > reverse); > > this stores to to_rtx which may be offsetted from target this means in this case > bitregion_end is not conservative enough - you'd need to resort to the > field width > in that case I guess (and for variable field size not specify any end > -- I suppose > the 'size' store_constructor gets might also be "unknown"?). But maybe all > the non-constant offset / size cases are "dead code" now that we are in GIMPLE? > Note they likely can only appear from Ada code anyway -- CCing Eric. > > I suppose a "safe" thing to do would be to give up on the first > variable offset/size > and re-set bitregion_end to zero for this and all following fields. Ok. I'm sending a patch that put gcc_unreachable to places where either size or (and) offset is a non-constant. This survives regression tests (including ada) on x86_64-linux-gnu. Apart from that normal bootstrap + regression tests works fine on ppc64le-redhat-linux. I'm not sure whether there can be a code that has variable size and offset? Martin > > The other cases look fine to me. > > Thanks, > Richard. > >> Martin >From c8d3e7c33c22bfdaf9e285e9e747701b8646cdf2 Mon Sep 17 00:00:00 2001 From: marxin Date: Tue, 22 Nov 2016 10:15:42 +0100 Subject: [PATCH] Fill bitregion_{start,end} in store_constructor (PR tree-optimization/78428). gcc/ChangeLog: 2016-12-08 Martin Liska * expr.c (store_constructor_field): Add new arguments to the function. (store_constructor): Set up bitregion_end and add gcc_unreachable to fields that have either non-constant size or (and) offset. gcc/testsuite/ChangeLog: 2016-12-08 Martin Liska * gcc.dg/tree-ssa/pr78428.c: New test. --- gcc/expr.c | 52 +++++++++++++-------------------- gcc/testsuite/gcc.dg/tree-ssa/pr78428.c | 27 +++++++++++++++++ 2 files changed, 47 insertions(+), 32 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr78428.c diff --git a/gcc/expr.c b/gcc/expr.c index fe752fb..88da8dd 100644 --- a/gcc/expr.c +++ b/gcc/expr.c @@ -80,7 +80,8 @@ static void clear_by_pieces (rtx, unsigned HOST_WIDE_INT, unsigned int); static rtx_insn *compress_float_constant (rtx, rtx); static rtx get_subtarget (rtx); static void store_constructor_field (rtx, unsigned HOST_WIDE_INT, - HOST_WIDE_INT, machine_mode, + HOST_WIDE_INT, unsigned HOST_WIDE_INT, + unsigned HOST_WIDE_INT, machine_mode, tree, int, alias_set_type, bool); static void store_constructor (tree, rtx, int, HOST_WIDE_INT, bool); static rtx store_field (rtx, HOST_WIDE_INT, HOST_WIDE_INT, @@ -6077,7 +6078,10 @@ all_zeros_p (const_tree exp) static void store_constructor_field (rtx target, unsigned HOST_WIDE_INT bitsize, - HOST_WIDE_INT bitpos, machine_mode mode, + HOST_WIDE_INT bitpos, + unsigned HOST_WIDE_INT bitregion_start, + unsigned HOST_WIDE_INT bitregion_end, + machine_mode mode, tree exp, int cleared, alias_set_type alias_set, bool reverse) { @@ -6112,8 +6116,8 @@ store_constructor_field (rtx target, unsigned HOST_WIDE_INT bitsize, reverse); } else - store_field (target, bitsize, bitpos, 0, 0, mode, exp, alias_set, false, - reverse); + store_field (target, bitsize, bitpos, bitregion_start, bitregion_end, mode, + exp, alias_set, false, reverse); } @@ -6148,6 +6152,7 @@ store_constructor (tree exp, rtx target, int cleared, HOST_WIDE_INT size, { tree type = TREE_TYPE (exp); HOST_WIDE_INT exp_size = int_size_in_bytes (type); + HOST_WIDE_INT bitregion_end = size > 0 ? size * BITS_PER_UNIT - 1 : 0; switch (TREE_CODE (type)) { @@ -6225,7 +6230,7 @@ store_constructor (tree exp, rtx target, int cleared, HOST_WIDE_INT size, if (tree_fits_uhwi_p (DECL_SIZE (field))) bitsize = tree_to_uhwi (DECL_SIZE (field)); else - bitsize = -1; + gcc_unreachable (); mode = DECL_MODE (field); if (DECL_BIT_FIELD (field)) @@ -6236,31 +6241,10 @@ store_constructor (tree exp, rtx target, int cleared, HOST_WIDE_INT size, && tree_fits_shwi_p (bit_position (field))) { bitpos = int_bit_position (field); - offset = 0; + offset = NULL_TREE; } else - bitpos = tree_to_shwi (DECL_FIELD_BIT_OFFSET (field)); - - if (offset) - { - machine_mode address_mode; - rtx offset_rtx; - - offset - = SUBSTITUTE_PLACEHOLDER_IN_EXPR (offset, - make_tree (TREE_TYPE (exp), - target)); - - offset_rtx = expand_normal (offset); - gcc_assert (MEM_P (to_rtx)); - - address_mode = get_address_mode (to_rtx); - if (GET_MODE (offset_rtx) != address_mode) - offset_rtx = convert_to_mode (address_mode, offset_rtx, 0); - - to_rtx = offset_address (to_rtx, offset_rtx, - highest_pow2_factor (offset)); - } + gcc_unreachable (); /* If this initializes a field that is smaller than a word, at the start of a word, try to widen it to a full @@ -6308,7 +6292,8 @@ store_constructor (tree exp, rtx target, int cleared, HOST_WIDE_INT size, MEM_KEEP_ALIAS_SET_P (to_rtx) = 1; } - store_constructor_field (to_rtx, bitsize, bitpos, mode, + store_constructor_field (to_rtx, bitsize, bitpos, + 0, bitregion_end, mode, value, cleared, get_alias_set (TREE_TYPE (field)), reverse); @@ -6468,7 +6453,8 @@ store_constructor (tree exp, rtx target, int cleared, HOST_WIDE_INT size, } store_constructor_field - (target, bitsize, bitpos, mode, value, cleared, + (target, bitsize, bitpos, 0, bitregion_end, + mode, value, cleared, get_alias_set (elttype), reverse); } } @@ -6571,7 +6557,8 @@ store_constructor (tree exp, rtx target, int cleared, HOST_WIDE_INT size, target = copy_rtx (target); MEM_KEEP_ALIAS_SET_P (target) = 1; } - store_constructor_field (target, bitsize, bitpos, mode, value, + store_constructor_field (target, bitsize, bitpos, 0, + bitregion_end, mode, value, cleared, get_alias_set (elttype), reverse); } @@ -6705,7 +6692,8 @@ store_constructor (tree exp, rtx target, int cleared, HOST_WIDE_INT size, ? TYPE_MODE (TREE_TYPE (value)) : eltmode; bitpos = eltpos * elt_size; - store_constructor_field (target, bitsize, bitpos, value_mode, + store_constructor_field (target, bitsize, bitpos, 0, + bitregion_end, value_mode, value, cleared, alias, reverse); } } diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr78428.c b/gcc/testsuite/gcc.dg/tree-ssa/pr78428.c new file mode 100644 index 0000000..3a9b99c --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr78428.c @@ -0,0 +1,27 @@ +/* PR tree-optimization/78428. */ +/* { dg-options "-O2" } */ +/* { dg-do run } */ + +struct S0 +{ + int f2; + int f3:16; + int f4:18; +} ; + +int a = 5; +struct S0 b = { 3, 0, 0 }; +static struct S0 global[2] = { { 77, 0, 78 }, { 77, 0, 78 } }; + +int main () +{ + volatile struct S0 *j; + for (; a;) + { + __builtin_printf ("", b.f2); + j = &b; + *j = global[1]; + a--; + } + return 0; +} -- 2.10.2