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 [216.205.24.124]) by sourceware.org (Postfix) with ESMTPS id 68FA53858C39 for ; Fri, 29 Oct 2021 08:06:40 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 68FA53858C39 Received: from mail-lj1-f200.google.com (mail-lj1-f200.google.com [209.85.208.200]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-321-7-477HH1OHGviTo45xRCDA-1; Fri, 29 Oct 2021 04:06:38 -0400 X-MC-Unique: 7-477HH1OHGviTo45xRCDA-1 Received: by mail-lj1-f200.google.com with SMTP id x8-20020a2e5848000000b00212c1f21630so304605ljd.20 for ; Fri, 29 Oct 2021 01:06:38 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=DgUqoGLIrLvd+1SX05zaGuyrTH2Evqmj/AztikzUqnQ=; b=OLmc5V97e0g220GYfbnbNmNCk4s1jumzviP/npzWPB2pPYXfnchAUjo+jkJLODSpiR UyktpFvxSBjwvO/uZNM34jWKIYCIEc2x/RHsOGT6LF9+383/yvD+S3hYsUXeWzc/J4GY f7qGf2+fVgmAkNIQaCsk+FxhAVNi32N55z7xIpXCEaEJuEUsjAAtJmSaKK2kQxeUmzy1 Q/aklSmG6TCAemEp148O+iM+yU+CIzoA/bIkQxOKGDJGT2R5BT/R9zBfAfUYrn18ywKX K5T+0iC3CNj06AXeO32FpdhQYPntp4DKo3zjBxRm7eP81wQW1lQX5cdpc1cztcFBdHNK xhIA== X-Gm-Message-State: AOAM5323pWPO4fFlyTV1Slogjvu1LZ2wkGoDpd9h17VfhA39au7TB9ov 8MYQPQMCMBlk4ETznd104YVBhC7t/dJEpNZzLDfNHE1dJ84RC8fsg4fmX4UuhVzYsjQka16Fqg1 pPX2trWpcBqAVmB75B91wV14ClDD1DMkfYQ== X-Received: by 2002:a05:6512:3092:: with SMTP id z18mr8916434lfd.396.1635494797269; Fri, 29 Oct 2021 01:06:37 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxE/xUwZu3rYoAgwKCsA5sgTiM+bJqE/S2FiFtX9tMYd4Xn26M6ornKyGviXHPXp/yJpAOuOFyAnzHNmWZq3Xw= X-Received: by 2002:a05:6512:3092:: with SMTP id z18mr8916413lfd.396.1635494796998; Fri, 29 Oct 2021 01:06:36 -0700 (PDT) MIME-Version: 1.0 References: <20211028152446.522454-1-aldyh@redhat.com> In-Reply-To: From: Aldy Hernandez Date: Fri, 29 Oct 2021 10:06:25 +0200 Message-ID: Subject: Re: [PATCH] Remove VRP threader passes in exchange for better threading pre-VRP. To: Richard Biener Cc: Jeff Law , GCC patches X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-6.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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: Fri, 29 Oct 2021 08:06:41 -0000 On Fri, Oct 29, 2021 at 9:30 AM Richard Biener wrote: > Btw, in case the "fully resolving" mode is slower than not fully resolving > please consider gating it on -fexpensive-optimizations (aka -O2+), thus > run the passes in not fully resolving modes at-O1. Sorry for the awkward naming. I couldn't find a better name :-/. Suggestions welcome. The fast mode assumes any unknown ranges on entry to a path to be VARYING, whereas the fully resolving mode will ask the ranger, so the fully resolving mode will indeed be slower. Though, I haven't measured how much. However, we are gaining some time in total compilation speed (1.32%) by replacing two threaders with one. > > Btw, there were quite a few big compile-time hogs with the vrp_threader > passes, not sure if this solves those. Sorry for not commenting on your spec ltrans report. I was waiting until this went in to get a better feel of whether it was the path solver, the forward threader, or something else. When I commit this patch we'll get the forward threader out of the set of variables to examine. The forward threader, for instance, has very few knobs limiting its behavior, and coupled with a smarter solver, who knows what's going on. It is possible we may need to add a few knobs (or re-add some of the ones I removed??), since the backward threader can find a whole slew of paths that the forward threader could never find. Aldy