From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by sourceware.org (Postfix) with ESMTPS id C8C9A3858D38 for ; Tue, 20 Jun 2023 07:36:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org C8C9A3858D38 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 E1F191F37E; Tue, 20 Jun 2023 07:36:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1687246582; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=hg/Rml2wSbAEe2mFLoj5FZ7ZvrUPRI+42Z1VKxNyH3I=; b=2Yy35zGdwiD6r3wEhJHSlYWFfVLkXYj8FIRvS92mgj0cnOK4bA+kdTBfYTefqN2sUyG96g J771dKSZ7SuW+j352JYKjf3neIJPFevKnzheZFz76IUZaWWXBImiSd5w7XTSyjBXOj+LQA uMrApGlAdYT4TIE0ODth0sdkAD3wC0I= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1687246582; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=hg/Rml2wSbAEe2mFLoj5FZ7ZvrUPRI+42Z1VKxNyH3I=; b=zhwBhpUS+DKl74FN+nqbom0A9YpehPgw629v20xMqbZRIu9c1Lqez/H17NjSpcm8CXpTH3 8XgdSH+5NhxtRTBw== 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 D3AFA2C141; Tue, 20 Jun 2023 07:36:22 +0000 (UTC) Date: Tue, 20 Jun 2023 07:36:22 +0000 (UTC) From: Richard Biener To: Richard Sandiford cc: Jeff Law , gcc-patches@gcc.gnu.org Subject: Re: [PATCH] tree-optimization/110243 - kill off IVOPTs split_offset In-Reply-To: Message-ID: References: <20230616123424.B38AC1330B@imap2.suse-dmz.suse.de> 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=-4.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE 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 Mon, 19 Jun 2023, Richard Sandiford wrote: > Jeff Law writes: > > On 6/16/23 06:34, Richard Biener via Gcc-patches wrote: > >> IVOPTs has strip_offset which suffers from the same issues regarding > >> integer overflow that split_constant_offset did but the latter was > >> fixed quite some time ago. The following implements strip_offset > >> in terms of split_constant_offset, removing the redundant and > >> incorrect implementation. > >> > >> The implementations are not exactly the same, strip_offset relies > >> on ptrdiff_tree_p to fend off too large offsets while split_constant_offset > >> simply assumes those do not happen and truncates them. By > >> the same means strip_offset also handles POLY_INT_CSTs but > >> split_constant_offset does not. Massaging the latter to > >> behave like strip_offset in those cases might be the way to go? > >> > >> Bootstrapped and tested on x86_64-unknown-linux-gnu. > >> > >> Comments? > >> > >> Thanks, > >> Richard. > >> > >> PR tree-optimization/110243 > >> * tree-ssa-loop-ivopts.cc (strip_offset_1): Remove. > >> (strip_offset): Make it a wrapper around split_constant_offset. > >> > >> * gcc.dg/torture/pr110243.c: New testcase. > > Your call -- IMHO you know this code far better than I. > > +1, but LGTM FWIW. I couldn't see anything obvious (and valid) > that split_offset_1 handles and split_constant_offset doesn't. I think it's only the INTEGER_CST vs. ptrdiff_tree_p where the latter (used in split_offset_1) handles POLY_INT_CSTs. split_offset also computes the offset in poly_int64 and checks it fits (to some extent) while split_constant_offset simply converts all INTEGER_CSTs to ssizetype because it knows it starts from addresses only. An alternative fix would have been to rewrite signed arithmetic to unsigned in strip_offset_1. I wonder if we want to change split_constant_offset to record the offset in a poly_int64 and have a wrapper converting it back to a tree for data-ref analysis. Then we can at least put cst_and_fits_in_hwi checks in the code? The code also tracks a range so it doesn't look like handling POLY_INT_CSTs is easy there - do you remember whether that was important for IVOPTs? Thanks, Richard.