From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by sourceware.org (Postfix) with ESMTPS id 8A22E3957787 for ; Sun, 11 Dec 2022 13:34:25 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 8A22E3957787 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=suse.de Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id C1A301FE44; Sun, 11 Dec 2022 13:34:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1670765664; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type; bh=b+gHsamhAsLr08kwVeYNJDQ821kSd/tR+AIderMRNYs=; b=RA28wcluYWA4/Pf7v0fFqYUXPdOZyZqQPnTF2OB8NQCjMbXdyK6/fT2e5IauT4sDonWn4a Xpmh7BjL4WhdbNbOrKV3lkE89PUh0A6DEisMG/8EBQICCBkcyggFslXzxtr9quTTQxrO42 757JOE+vsei8UGyQ20Y5p/YkO1CgPS4= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1670765664; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type; bh=b+gHsamhAsLr08kwVeYNJDQ821kSd/tR+AIderMRNYs=; b=GIofir3kRtbIk19stwSjrCHEqZHqOqR69XAErofAqHT9s7c8yBU3Dk9X1JtgQtZwhWs4Di MAfmwnAu8YQR0CDQ== Received: from wotan.suse.de (wotan.suse.de [10.160.0.1]) (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 ABBF32C141; Sun, 11 Dec 2022 13:34:23 +0000 (UTC) Date: Sun, 11 Dec 2022 13:34:23 +0000 (UTC) From: Richard Biener To: gcc-patches@gcc.gnu.org cc: Jakub Jelinek Subject: Re: [PATCH] tree-optimization/106904 - bogus -Wstringopt-overflow with vectors Message-ID: User-Agent: Alpine 2.22 (LSU 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Spam-Status: No, score=-11.1 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Wed, 7 Dec 2022, Richard Biener wrote: > The following avoids CSE of &ps->wp to &ps->wp.hwnd confusing > -Wstringopt-overflow by making sure to produce addresses to the > biggest container from vectorization. For this I introduce > strip_zero_offset_components which turns &ps->wp.hwnd into > &(*ps) and use that to base the vector data references on. > That will also work for addresses with variable components, > alternatively emitting pointer arithmetic via calling > get_inner_reference and gimplifying that would be possible > but likely more intrusive. > > This is by no means a complete fix for all of those issues > (avoiding ADDR_EXPRs in favor of pointer arithmetic might be). > Other passes will have similar issues. > > In theory that might now cause false negatives. > > Bootstrap and regtest running on x86_64-unknown-linux-gnu. > > Any opinion? I have now pushed this. Richard. > Thanks, > Richard. > > PR tree-optimization/106904 > * tree.h (strip_zero_offset_components): Declare. > * tree.cc (strip_zero_offset_components): Define. > * tree-vect-data-refs.cc (vect_create_addr_base_for_vector_ref): > Strip zero offset components before building the address. > > * gcc.dg/Wstringop-overflow-pr106904.c: New testcase. > --- > .../gcc.dg/Wstringop-overflow-pr106904.c | 30 +++++++++++++++++++ > gcc/tree-vect-data-refs.cc | 12 ++++---- > gcc/tree.cc | 12 ++++++++ > gcc/tree.h | 1 + > 4 files changed, 50 insertions(+), 5 deletions(-) > create mode 100644 gcc/testsuite/gcc.dg/Wstringop-overflow-pr106904.c > > diff --git a/gcc/testsuite/gcc.dg/Wstringop-overflow-pr106904.c b/gcc/testsuite/gcc.dg/Wstringop-overflow-pr106904.c > new file mode 100644 > index 00000000000..15e67c28c15 > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/Wstringop-overflow-pr106904.c > @@ -0,0 +1,30 @@ > +/* { dg-do compile } */ > +/* { dg-options "-O2 -Wstringop-overflow -fno-vect-cost-model" } */ > + > +struct windowpos > +{ > + int hwnd; > + int hwnd2; > +}; > + > +struct packed_windowpos > +{ > + int hwnd; > + int pad1; > + int hwnd2; > + int pad2; > +}; > + > +struct packed_structs > +{ > + struct packed_windowpos wp; > +}; > + > +void func(struct packed_structs *ps) > +{ > + struct windowpos wp; > + > + wp.hwnd = ps->wp.hwnd; > + wp.hwnd2 = ps->wp.hwnd2; > + __builtin_memcpy(&ps->wp, &wp, sizeof(wp)); /* { dg-bogus "into a region" } */ > +} > diff --git a/gcc/tree-vect-data-refs.cc b/gcc/tree-vect-data-refs.cc > index 6c892791bd4..18b0f962670 100644 > --- a/gcc/tree-vect-data-refs.cc > +++ b/gcc/tree-vect-data-refs.cc > @@ -4845,11 +4845,13 @@ vect_create_addr_base_for_vector_ref (vec_info *vinfo, stmt_vec_info stmt_info, > if (loop_vinfo) > addr_base = fold_build_pointer_plus (data_ref_base, base_offset); > else > - { > - addr_base = build1 (ADDR_EXPR, > - build_pointer_type (TREE_TYPE (DR_REF (dr))), > - unshare_expr (DR_REF (dr))); > - } > + addr_base = build1 (ADDR_EXPR, > + build_pointer_type (TREE_TYPE (DR_REF (dr))), > + /* Strip zero offset components since we don't need > + them and they can confuse late diagnostics if > + we CSE them wrongly. See PR106904 for example. */ > + unshare_expr (strip_zero_offset_components > + (DR_REF (dr)))); > > vect_ptr_type = build_pointer_type (TREE_TYPE (DR_REF (dr))); > dest = vect_get_new_vect_var (vect_ptr_type, vect_pointer_var, base_name); > diff --git a/gcc/tree.cc b/gcc/tree.cc > index b40c95ae8c4..0a51f9ddb4d 100644 > --- a/gcc/tree.cc > +++ b/gcc/tree.cc > @@ -12014,6 +12014,18 @@ strip_invariant_refs (const_tree op) > return op; > } > > +/* Strip handled components with zero offset from OP. */ > + > +tree > +strip_zero_offset_components (tree op) > +{ > + while (TREE_CODE (op) == COMPONENT_REF > + && integer_zerop (DECL_FIELD_OFFSET (TREE_OPERAND (op, 1))) > + && integer_zerop (DECL_FIELD_BIT_OFFSET (TREE_OPERAND (op, 1)))) > + op = TREE_OPERAND (op, 0); > + return op; > +} > + > static GTY(()) tree gcc_eh_personality_decl; > > /* Return the GCC personality function decl. */ > diff --git a/gcc/tree.h b/gcc/tree.h > index 1c810c0b21b..065ad527c3f 100644 > --- a/gcc/tree.h > +++ b/gcc/tree.h > @@ -5373,6 +5373,7 @@ extern bool tree_nop_conversion_p (const_tree, const_tree); > extern tree tree_strip_nop_conversions (tree); > extern tree tree_strip_sign_nop_conversions (tree); > extern const_tree strip_invariant_refs (const_tree); > +extern tree strip_zero_offset_components (tree); > extern tree lhd_gcc_personality (void); > extern void assign_assembler_name_if_needed (tree); > extern bool warn_deprecated_use (tree, tree); > -- Richard Biener SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg, Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman; HRB 36809 (AG Nuernberg)