From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by sourceware.org (Postfix) with ESMTPS id 5FCB338582BE for ; Wed, 24 Aug 2022 06:48:34 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 5FCB338582BE 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-out1.suse.de (Postfix) with ESMTP id 25F10339FA; Wed, 24 Aug 2022 06:48:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1661323712; 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=5A0R6DWsaAI+Psw/kAkKmpoBNqjrVWORlcfd1HUicOo=; b=v0Ph2KHVBY42hXjFcMFoHehYpaXIio4pqcM1nQOZ3pLuV+OOxhlKQ5XC5LqKPD+NqgKh1Z QpF4WwFmC5hqdGVTpCmb6kftCN9zrmZwmBb0dpYVsSRkMheJQ4I5NYqFjYJEJrpxBsB1wz 0biv6NTW+yHiBN7I4C3us8x5WJ1SoAM= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1661323712; 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=5A0R6DWsaAI+Psw/kAkKmpoBNqjrVWORlcfd1HUicOo=; b=kYqhbcKkEXSK+HrON0ZH7I1mkvLrfNt86aoGnLNiV13JTRewi5+Dnibca7YHomFp2b4GbX TKyZlA+P6ASjTfDw== 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 205CF2C141; Wed, 24 Aug 2022 06:48:32 +0000 (UTC) Date: Wed, 24 Aug 2022 06:48:32 +0000 (UTC) From: Richard Biener To: Aldy Hernandez cc: gcc-patches Subject: Re: [PATCH] Speedup path discovery in predicate::use_cannot_happen In-Reply-To: Message-ID: References: <80496.122082308163400337@us-mta-60.us.mimecast.lan> 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=-5.0 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 Tue, 23 Aug 2022, Aldy Hernandez wrote: > On Tue, Aug 23, 2022 at 2:16 PM Richard Biener wrote: > > > > The following reverts a hunk from r8-5789-g11ef0b22d68cd1 that > > made compute_control_dep_chain start from function entry rather > > than the immediate dominator of the source block of the edge with > > the undefined value on the PHI node. Reverting at that point > > does not reveal any testsuite FAIL, in particular the added > > testcase still passes. The following adjusts this to the other > > function that computes predicates that hold on the PHI incoming > > edges with undefined values, predicate::init_from_phi_def, which > > starts at the immediate dominator of the PHI. That's much less > > likely to run into the CFG walking limit. > > > > Bootstrapped and tested on x86_64-unknown-linux-gnu. > > > > Aldy - you did this change, do you remember anything here? In > > fact the whole thing that's now called predicate::use_cannot_happen > > seems to be redundant - the two testcases attributed to its history > > do not fail when that's disabled, nor did they fail when it was > > introduced. In principle whats now called predicate::superset_of > > should cover this (but different implementation limits might apply). > > OMG, I'm drawing a complete blank here. I have no recollection of > this. I'm tempted to say either my account was hacked or that old > code was all wrong ;-). Eh. Pushed then. I'm going to baby-step changes so we can figure out things when later bisecting regressions ... Thanks, Richard.