From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 56A263858D32 for ; Tue, 23 Aug 2022 15:24:42 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 56A263858D32 Received: from mail-oa1-f70.google.com (mail-oa1-f70.google.com [209.85.160.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-404-toXQJXwYMVCtu1jH6ku3Tg-1; Tue, 23 Aug 2022 11:24:40 -0400 X-MC-Unique: toXQJXwYMVCtu1jH6ku3Tg-1 Received: by mail-oa1-f70.google.com with SMTP id 586e51a60fabf-10ecd047e39so4147807fac.5 for ; Tue, 23 Aug 2022 08:24:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc; bh=SEup7p4wtSeZeXxCydOmT+pJAxjJ62g4y7OfzOlVefU=; b=1DR1btUEIvKLuDtUz/HFeomtXr5KiS89uMdcHbI5ch55mlXdevoG6DTP8LkOtM7CIG vBe6+yuSbViJ6B3b0X331iTVxF3ot+rbcvOXG8aFy5wUNhbOUusZzxlR4f39Gd7pXRoy u9SBkKOBKHpfV3jIlB1Z8nBaNk0SdoC4ZLaSlWRBx3gxg+xO4yCdFKVM+IOkq/iBEKB3 ZtSVu5nTAwGv5uc2WQlyhE7Z2m5NkHFKZTqblWrlHDs1Rckp+v8X6ufYy7QNiSv2tt5k eOPeX1Ga4v4yNDk5UNUoXr1MF2OU+kuV5ElkV263Zi3Khjy+lizLm7ktrAyld/GC0Nku /tag== X-Gm-Message-State: ACgBeo39WTfwlDQ+gdmmc9+h5FDqU7MU10EKfOIWWKal8UghaS+db8NC IR6Fa099fJ2jM/x8oJ+UbOErIeMt9NaUL5aZ6k9LN2UtzkpYRw4bKsfTNj+b00kpso2Xe1SINjq X3w8XtPZgYHPIFsSBmHC9VNtrx12s6XxPEA== X-Received: by 2002:a05:6830:12d5:b0:638:e048:ef97 with SMTP id a21-20020a05683012d500b00638e048ef97mr9642634otq.276.1661268280298; Tue, 23 Aug 2022 08:24:40 -0700 (PDT) X-Google-Smtp-Source: AA6agR5ObAyj9COnD4eyA34031Qs+Yl2F9ZhF39TcEQZQEcvQqS5UpXVjBHE/BdW+x9mhxNjTOxDl8x3X4gCJpZZ1XA= X-Received: by 2002:a05:6830:12d5:b0:638:e048:ef97 with SMTP id a21-20020a05683012d500b00638e048ef97mr9642623otq.276.1661268280047; Tue, 23 Aug 2022 08:24:40 -0700 (PDT) MIME-Version: 1.0 References: <80496.122082308163400337@us-mta-60.us.mimecast.lan> In-Reply-To: <80496.122082308163400337@us-mta-60.us.mimecast.lan> From: Aldy Hernandez Date: Tue, 23 Aug 2022 17:24:29 +0200 Message-ID: Subject: Re: [PATCH] Speedup path discovery in predicate::use_cannot_happen To: Richard Biener Cc: gcc-patches X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-5.5 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_NONE, 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 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: Tue, 23 Aug 2022 15:24:43 -0000 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 ;-). Sorry. Aldy