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 4DCB03858433 for ; Mon, 7 Nov 2022 20:10:24 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 4DCB03858433 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667851823; h=from:from:reply-to:subject:subject: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=blgPztyk3JZjEQs5mGV89h1jflH0r7G/cuLu0UgIQrI=; b=PHIx7H+YYIGF9NVCgTvFG7rMQmxtTbBm2geT7/JyUhEAua9njwTi9uxKoHnDFaFQTuat4g F5VXdSDyqcr1/wrs3mY8VvOMYTl9voT0/vJ24ZZ2kXuuxT7gxj5g97Fa4hLfZl6q0jVlKk wI73B3pdmlT1OrH+SRo0ukpvD+O2YDk= Received: from mail-yw1-f197.google.com (mail-yw1-f197.google.com [209.85.128.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-48-lR3J6_Y0N86ikrufhFF4Xg-1; Mon, 07 Nov 2022 15:10:22 -0500 X-MC-Unique: lR3J6_Y0N86ikrufhFF4Xg-1 Received: by mail-yw1-f197.google.com with SMTP id 00721157ae682-352e29ff8c2so118546527b3.21 for ; Mon, 07 Nov 2022 12:10:22 -0800 (PST) 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:subject:date:message-id :reply-to; bh=blgPztyk3JZjEQs5mGV89h1jflH0r7G/cuLu0UgIQrI=; b=f9Y5nZRxC9wleT1XiDZDIyL0jyXQjlUszfmkQaBnBe5YrWLuYHEk36Tb+sGIYW+5/A oxaUmOyYVcgWAzmorhTZw80C08xy7y31oMGJRU3OdcLQzzc9/moALy9UvcTpOqJUir7q gEdfnhL+9vPLgU67UgNQnrS+fdZP+vX+HX6PMwl8xcw31NIEcZpJL97oOpp/nsM5HLKf vRhEANESQTutKD2LR7doWc4RpizYAncqAKFAXVHfxjJQajtxkeFD7PPay+bgW//D2vHZ QkeXReSJXRobkmb+s3v93NXMMQj9bAF5oFKKvF3PR+2iLoqWH4ws1w3BLO8Pmlz9zLqC fydQ== X-Gm-Message-State: ACrzQf1GuALbFtEexAB3WEt+nRkyJqE13d1qDnJuZ3sDyiRXzYI1DUHL h45IhBqyOxnsDWxTlT2g4s+nFAXyVxUl5Eid8m88Ca2Jk4C9FNQ8MOeV7NXHXiy6RzcvFov0+sy OABYmPQLzLxShPqmSXkcJHmth6LYak9c7dg== X-Received: by 2002:a25:df10:0:b0:6cf:f148:7cdb with SMTP id w16-20020a25df10000000b006cff1487cdbmr29889620ybg.80.1667851821852; Mon, 07 Nov 2022 12:10:21 -0800 (PST) X-Google-Smtp-Source: AMsMyM7cfrYp14WziIjyLmACKMz8v6lT/jZ73k6AyNdK8Rh1N+1dHe/F+y8qfEmcWyvDID1hdF74db/dqb7IlQrUBTQ= X-Received: by 2002:a25:df10:0:b0:6cf:f148:7cdb with SMTP id w16-20020a25df10000000b006cff1487cdbmr29889604ybg.80.1667851821647; Mon, 07 Nov 2022 12:10:21 -0800 (PST) MIME-Version: 1.0 References: <20221107195856.791257-1-aldyh@redhat.com> In-Reply-To: <20221107195856.791257-1-aldyh@redhat.com> From: Aldy Hernandez Date: Mon, 7 Nov 2022 21:10:10 +0100 Message-ID: Subject: Re: [COMMITTED] Improve multiplication by powers of 2 in range-ops. To: GCC patches Cc: Andrew MacLeod X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,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 Mon, Nov 7, 2022 at 8:59 PM Aldy Hernandez wrote: > > For unsigned numbers, multiplication by X, where X is a power of 2 is > [0,0][X,+INF]. > > This patch causes a regression to g++.dg/pr71488.C where > -Wstringop-overflow gets the same IL as before, but better ranges > cause it to issue a bogus warning. I will create a PR with some > notes. PR107561