From patchwork Wed Jun 16 08:43:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pierre-Marie de Rodat X-Patchwork-Id: 1492829 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org (client-ip=2620:52:3:1:0:246e:9693:128c; helo=sourceware.org; envelope-from=gcc-patches-bounces+incoming=patchwork.ozlabs.org@gcc.gnu.org; receiver=) Received: from sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4G4fCb6xhSz9sXL for ; Wed, 16 Jun 2021 18:55:23 +1000 (AEST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 455E539960E8 for ; Wed, 16 Jun 2021 08:55:21 +0000 (GMT) X-Original-To: gcc-patches@gcc.gnu.org Delivered-To: gcc-patches@gcc.gnu.org Received: from rock.gnat.com (rock.gnat.com [IPv6:2620:20:4000:0:a9e:1ff:fe9b:1d1]) by sourceware.org (Postfix) with ESMTPS id 1E6F0398900C for ; Wed, 16 Jun 2021 08:44:00 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 1E6F0398900C Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=adacore.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=adacore.com Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id 3AE215615E; Wed, 16 Jun 2021 04:43:56 -0400 (EDT) X-Virus-Scanned: Debian amavisd-new at gnat.com Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id z-tdX8Tkb6sY; Wed, 16 Jun 2021 04:43:56 -0400 (EDT) Received: from tron.gnat.com (tron.gnat.com [205.232.38.10]) by rock.gnat.com (Postfix) with ESMTP id 1BE5056158; Wed, 16 Jun 2021 04:43:56 -0400 (EDT) Received: by tron.gnat.com (Postfix, from userid 4862) id 17DA1180; Wed, 16 Jun 2021 04:43:56 -0400 (EDT) Date: Wed, 16 Jun 2021 04:43:56 -0400 From: Pierre-Marie de Rodat To: gcc-patches@gcc.gnu.org Subject: [Ada] Fix floating-point exponentiation with Integer'First exponent Message-ID: <20210616084356.GA96108@adacore.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Status: No, score=-12.6 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) 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: , Cc: Eric Botcazou Errors-To: gcc-patches-bounces+incoming=patchwork.ozlabs.org@gcc.gnu.org Sender: "Gcc-patches" It works neither at compile time nor at run time because of the classical issue that -Integer'First is not a valid Integer value. Tested on x86_64-pc-linux-gnu, committed on trunk gcc/ada/ * urealp.adb (Scale): Change first paramter to Uint and adjust. (Equivalent_Decimal_Exponent): Pass U.Den directly to Scale. * libgnat/s-exponr.adb (Negative): Rename to... (Safe_Negative): ...this and change its lower bound. (Exponr): Adjust to above renaming and deal with Integer'First. diff --git a/gcc/ada/libgnat/s-exponr.adb b/gcc/ada/libgnat/s-exponr.adb --- a/gcc/ada/libgnat/s-exponr.adb +++ b/gcc/ada/libgnat/s-exponr.adb @@ -57,8 +57,8 @@ function System.Exponr (Left : Num; Right : Integer) return Num is subtype Double_T is Double_Real.Double_T; -- The double floating-point type - subtype Negative is Integer range Integer'First .. -1; - -- The range of negative exponents + subtype Safe_Negative is Integer range Integer'First + 1 .. -1; + -- The range of safe negative exponents function Expon (Left : Num; Right : Natural) return Num; -- Routine used if Right is greater than 4 @@ -113,9 +113,12 @@ begin return Num'Machine (Sqr * Sqr); end; - when Negative => + when Safe_Negative => return Num'Machine (1.0 / Exponr (Left, -Right)); + when Integer'First => + return Num'Machine (1.0 / (Exponr (Left, Integer'Last) * Left)); + when others => return Num'Machine (Expon (Left, Right)); end case; diff --git a/gcc/ada/urealp.adb b/gcc/ada/urealp.adb --- a/gcc/ada/urealp.adb +++ b/gcc/ada/urealp.adb @@ -270,23 +270,21 @@ package body Urealp is 15 => (Num => 53_385_559, Den => 45_392_361), -- 1.176091259055681 16 => (Num => 78_897_839, Den => 65_523_237)); -- 1.204119982655924 - function Scale (X : Int; R : Ratio) return Int; + function Scale (X : Uint; R : Ratio) return Int; -- Compute the value of X scaled by R ----------- -- Scale -- ----------- - function Scale (X : Int; R : Ratio) return Int is - type Wide_Int is range -2**63 .. 2**63 - 1; - + function Scale (X : Uint; R : Ratio) return Int is begin - return Int (Wide_Int (X) * Wide_Int (R.Num) / Wide_Int (R.Den)); + return UI_To_Int (X * R.Num / R.Den); end Scale; begin pragma Assert (U.Rbase /= 0); - return Scale (UI_To_Int (U.Den), Logs (U.Rbase)); + return Scale (U.Den, Logs (U.Rbase)); end Equivalent_Decimal_Exponent; ----------------