From patchwork Fri Mar 14 13:54:29 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella Netto X-Patchwork-Id: 88 X-Patchwork-Delegate: azanella@linux.vnet.ibm.com Return-Path: X-Original-To: siddhesh@wilcox.dreamhost.com Delivered-To: siddhesh@wilcox.dreamhost.com Received: from homiemail-mx23.g.dreamhost.com (caibbdcaabja.dreamhost.com [208.113.200.190]) by wilcox.dreamhost.com (Postfix) with ESMTP id 6FEF03600AB for ; Fri, 14 Mar 2014 06:54:41 -0700 (PDT) Received: by homiemail-mx23.g.dreamhost.com (Postfix, from userid 14307373) id 2F4E16366F0B9; Fri, 14 Mar 2014 06:54:41 -0700 (PDT) X-Original-To: glibc@patchwork.siddhesh.in Delivered-To: x14307373@homiemail-mx23.g.dreamhost.com Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by homiemail-mx23.g.dreamhost.com (Postfix) with ESMTPS id 109F16366F080 for ; Fri, 14 Mar 2014 06:54:41 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:message-id:date:from:mime-version:to:subject :content-type:content-transfer-encoding; q=dns; s=default; b=azy p6deml5yEhUFyUnBfQeg31Gsk086kJG2IB+/fXV4Y4D8eDPvEoB0ShLY2+gSSNBD 2cFdzCigDVWCDQrsgY85v1G0ydtuRdKiV2d7siaujd49E8d79jOVlQGGYAnGu8oc 8QTEY/326UAOkZ+7bCvSi+Qyb4EJb5UaIp+gaSvA= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:message-id:date:from:mime-version:to:subject :content-type:content-transfer-encoding; s=default; bh=ULe71uZ1A EQ+kJhsZo87T9g9uAQ=; b=EOkQYuSY3Et9Dp9m5IinrBgXj9/oL7u1GWNhCY8xS mRiUimt9Qa2HpfQs+zsEJmD8TZHY2Fs9+MWAsxHwi1BPUDsn1HO0yRchI4cGpdR/ 385FjTLQNF/7o+vOnm4Dl6pggpMz2jnG4lkr97kKCj2aKzTjTEawbRnZbS9cR7zz HI= Received: (qmail 9942 invoked by alias); 14 Mar 2014 13:54:39 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 9931 invoked by uid 89); 14 Mar 2014 13:54:39 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.8 required=5.0 tests=AWL, BAYES_00, T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: e24smtp02.br.ibm.com Message-ID: <53230A15.9060203@linux.vnet.ibm.com> Date: Fri, 14 Mar 2014 10:54:29 -0300 From: Adhemerval Zanella User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: "GNU C. Library" Subject: [PATCH 3/3] PowerPC: remove wrong roundl implementation for PowerPC64 X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14031413-2194-0000-0000-00000847889B X-DH-Original-To: glibc@patchwork.siddhesh.in The roundl assembly implementation (sysdeps/powerpc/powerpc64/fpu/s_roundl.S) returns wrong results for some inputs where first double is a exact integer and the precision is determined by second long double. Checking on implementation comments and history, I am very confident the assembly implementation was based on a version before commit 5c68d401698a58cf7da150d9cce769fa6679ba5f that fixes BZ#2423 (Errors in long double (ldbl-128ibm) rounding functions in glibc-2.4). By just removing the implementation and make the build select sysdeps/ieee754/ldbl-128ibm/s_roundl.c instead fixes the failing math. Fixes BZ#16707. Test on PPC64 and PPC64LE. If no one opposes it, I'll commit in a couple of hours. --- 2014-03-14 Adhemerval Zanella [BZ #16707] * sysdeps/powerpc/powerpc64/fpu/s_roundl.S: Remove wrong implementation. * math/libm-test.inc (round_test_data): Add more tests. --- diff --git a/NEWS b/NEWS index c9bfcb8..443b146 100644 --- a/NEWS +++ b/NEWS @@ -11,7 +11,7 @@ Version 2.20 15347, 15804, 15894, 16447, 16532, 16545, 16574, 16600, 16609, 16610, 16611, 16613, 16623, 16632, 16639, 16642, 16670, 16674, 16677, 16683, - 16689, 16695, 16701, 16706. + 16689, 16695, 16701, 16706, 16707. * The am33 port, which had not worked for several years, has been removed from ports. diff --git a/math/libm-test.inc b/math/libm-test.inc index ee0a353..378c79d 100644 --- a/math/libm-test.inc +++ b/math/libm-test.inc @@ -10625,6 +10625,13 @@ static const struct test_f_f_data round_test_data[] = TEST_f_f (round, -72057594037927936.75L, -72057594037927937.0L), TEST_f_f (round, -72057594037927937.5L, -72057594037927938.0L), + /* Check cases where first double is a exact integer higher than 2^52 and + the precision is determined by second long double for IBM long double. */ + TEST_f_f (round, 34503599627370498.515625L, 34503599627370499.0L), + TEST_f_f (round, 1192568192774434123539907640624.484375L, 1192568192774434123539907640624.0L), + TEST_f_f (round, -34503599627370498.515625L, -34503599627370499.0L), + TEST_f_f (round, -1192568192774434123539907640624.484375L, -1192568192774434123539907640624.0L), + TEST_f_f (round, 10141204801825835211973625643007.5L, 10141204801825835211973625643008.0L), TEST_f_f (round, 10141204801825835211973625643008.25L, 10141204801825835211973625643008.0L), TEST_f_f (round, 10141204801825835211973625643008.5L, 10141204801825835211973625643009.0L), diff --git a/sysdeps/powerpc/powerpc64/fpu/s_roundl.S b/sysdeps/powerpc/powerpc64/fpu/s_roundl.S deleted file mode 100644 index 5362da8..0000000 --- a/sysdeps/powerpc/powerpc64/fpu/s_roundl.S +++ /dev/null @@ -1,132 +0,0 @@ -/* long double round function. - IBM extended format long double version. - Copyright (C) 2004-2014 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#include -#include - - .section ".toc","aw" -.LC0: /* 2**52 */ - .tc FD_43300000_0[TC],0x4330000000000000 -.LC1: /* 0.5 */ - .tc FD_3fe00000_0[TC],0x3fe0000000000000 - .section ".text" - -/* long double [fp1,fp2] roundl (long double x [fp1,fp2]) - IEEE 1003.1 round function. IEEE specifies "round to the nearest - integer value, rounding halfway cases away from zero, regardless of - the current rounding mode." However PowerPC Architecture defines - "Round to Nearest" as "Choose the best approximation. In case of a - tie, choose the one that is even (least significant bit o).". - So we can't use the PowerPC "Round to Nearest" mode. Instead we set - "Round toward Zero" mode and round by adding +-0.5 before rounding - to the integer value. */ - -ENTRY (__roundl) - mffs fp11 /* Save current FPU rounding mode. */ - lfd fp13,.LC0@toc(2) - fabs fp0,fp1 - fabs fp9,fp2 - fsub fp12,fp13,fp13 /* generate 0.0 */ - fcmpu cr7,fp0,fp13 /* if (fabs(x) > TWO52) */ - fcmpu cr6,fp1,fp12 /* if (x > 0.0) */ - bnl- cr7,.L2 - mtfsfi 7,1 /* Set rounding mode toward 0. */ - lfd fp10,.LC1@toc(2) - ble- cr6,.L1 - fneg fp2,fp12 - fadd fp1,fp1,fp10 /* x+= 0.5; */ - fadd fp1,fp1,fp13 /* x+= TWO52; */ - fsub fp1,fp1,fp13 /* x-= TWO52; */ - fabs fp1,fp1 /* if (x == 0.0) x = 0.0; */ -.L0: - mtfsf 0x01,fp11 /* restore previous rounding mode. */ - blr -.L1: - fsub fp9,fp1,fp10 /* x-= 0.5; */ - fneg fp2,fp12 - bge- cr6,.L0 /* if (x < 0.0) */ - fsub fp1,fp9,fp13 /* x-= TWO52; */ - fadd fp1,fp1,fp13 /* x+= TWO52; */ - fnabs fp1,fp1 /* if (x == 0.0) x = -0.0; */ - mtfsf 0x01,fp11 /* restore previous rounding mode. */ - blr - -/* The high double is > TWO52 so we need to round the low double and - perhaps the high double. In this case we have to round the low - double and handle any adjustment to the high double that may be - caused by rounding (up). This is complicated by the fact that the - high double may already be rounded and the low double may have the - opposite sign to compensate.This gets a bit tricky so we use the - following algorithm: - - tau = floor(x_high/TWO52); - x0 = x_high - tau; - x1 = x_low + tau; - r1 = rint(x1); - y_high = x0 + r1; - y_low = x0 - y_high + r1; - return y; */ -.L2: - fcmpu cr7,fp9,fp13 /* if (|x_low| > TWO52) */ - fcmpu cr0,fp9,fp12 /* || (|x_low| == 0.0) */ - fcmpu cr5,fp2,fp12 /* if (x_low > 0.0) */ - lfd fp10,.LC1@toc(2) - bgelr- cr7 /* return x; */ - beqlr- cr0 - mtfsfi 7,1 /* Set rounding mode toward 0. */ - fdiv fp8,fp1,fp13 /* x_high/TWO52 */ - - bng- cr6,.L6 /* if (x > 0.0) */ - fctidz fp0,fp8 - fcfid fp8,fp0 /* tau = floor(x_high/TWO52); */ - bng cr5,.L4 /* if (x_low > 0.0) */ - fmr fp3,fp1 - fmr fp4,fp2 - b .L5 -.L4: /* if (x_low < 0.0) */ - fsub fp3,fp1,fp8 /* x0 = x_high - tau; */ - fadd fp4,fp2,fp8 /* x1 = x_low + tau; */ -.L5: - fadd fp5,fp4,fp10 /* r1 = x1 + 0.5; */ - fadd fp5,fp5,fp13 /* r1 = r1 + TWO52; */ - fsub fp5,fp5,fp13 /* r1 = r1 - TWO52; */ - b .L9 -.L6: /* if (x < 0.0) */ - fctidz fp0,fp8 - fcfid fp8,fp0 /* tau = floor(x_high/TWO52); */ - bnl cr5,.L7 /* if (x_low < 0.0) */ - fmr fp3,fp1 - fmr fp4,fp2 - b .L8 -.L7: /* if (x_low > 0.0) */ - fsub fp3,fp1,fp8 /* x0 = x_high - tau; */ - fadd fp4,fp2,fp8 /* x1 = x_low + tau; */ -.L8: - fsub fp5,fp4,fp10 /* r1 = x1 - 0.5; */ - fsub fp5,fp5,fp13 /* r1-= TWO52; */ - fadd fp5,fp5,fp13 /* r1+= TWO52; */ -.L9: - mtfsf 0x01,fp11 /* restore previous rounding mode. */ - fadd fp1,fp3,fp5 /* y_high = x0 + r1; */ - fsub fp2,fp3,fp1 /* y_low = x0 - y_high + r1; */ - fadd fp2,fp2,fp5 - blr -END (__roundl) - -long_double_symbol (libm, __roundl, roundl)