From patchwork Wed Aug 22 12:29:12 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wilco Dijkstra X-Patchwork-Id: 29011 Received: (qmail 96247 invoked by alias); 22 Aug 2018 12:29:19 -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 95509 invoked by uid 89); 22 Aug 2018 12:29:19 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-26.9 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, SPF_HELO_PASS, SPF_PASS autolearn=ham version=3.3.2 spammy=1995, 1.4, quality X-HELO: EUR02-VE1-obe.outbound.protection.outlook.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=armh.onmicrosoft.com; s=selector1-arm-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=a+JrETItuzKUa+KEYSl1nbcv3LXGyhAHv3gNeU60Ers=; b=ZKI2M0sMuPouYigS45Kao01xH5kox/4RO3lWKOD7JCZLMoTdYWV7TKvxn+u1oyEI0ETz1Igp4b01sdaXg3xy0pkHKETjqzITqsAGrhawrTyUAqhySrZibWOTV2BxJn+7ZRv/ap6i0O72mVjGFgn7WGK+djYTuVVTSZNcpx+AiRg= From: Wilco Dijkstra To: "libc-alpha@sourceware.org" CC: nd Subject: [PATCH] Speedup tanf range reduction Date: Wed, 22 Aug 2018 12:29:12 +0000 Message-ID: authentication-results: spf=none (sender IP is ) smtp.mailfrom=Wilco.Dijkstra@arm.com; received-spf: None (protection.outlook.com: arm.com does not designate permitted sender hosts) MIME-Version: 1.0 Speedup tanf range reduction by using the new sincosf range reduction algorithm. Overall code quality is improved due to inlining, so there is a speedup even if no range reduction is required. Passes GLIBC testsuite on AArch64. Some files are no longer required - they are removed in the next patch. tanf througput gains on Cortex-A72: * |x| < M_PI_4 : 1.1x * |x| < M_PI_2 : 1.2x * |x| < 2 * M_PI: 1.5x * |x| < 120.0 : 1.6x * |x| < Inf : 12.1x ChangeLog: 2018-08-22 Wilco Dijkstra * sysdeps/ieee754/flt-32/s_tanf.c (__tanf): Use fast range reduction. diff --git a/sysdeps/ieee754/flt-32/s_tanf.c b/sysdeps/ieee754/flt-32/s_tanf.c index ba3af54913669e4abdfd864307856ec44138f9b9..a397665c4bab7785049935ef526472afedf82e34 100644 --- a/sysdeps/ieee754/flt-32/s_tanf.c +++ b/sysdeps/ieee754/flt-32/s_tanf.c @@ -21,6 +21,30 @@ static char rcsid[] = "$NetBSD: s_tanf.c,v 1.4 1995/05/10 20:48:20 jtc Exp $"; #include #include #include +#include "s_sincosf.h" + +static inline int32_t +rem_pio2f (float x, float *y) +{ + double dx = x; + int n; + const sincos_t *p = &__sincosf_table[0]; + + if (__glibc_likely (abstop12 (x) < abstop12 (120.0f))) + dx = reduce_fast (dx, p, &n); + else + { + uint32_t xi = asuint (x); + int sign = xi >> 31; + + dx = reduce_large (xi, &n); + dx = sign ? -dx : dx; + } + + y[0] = dx; + y[1] = dx - y[0]; + return n; +} float __tanf(float x) { @@ -42,7 +66,7 @@ float __tanf(float x) /* argument reduction needed */ else { - n = __ieee754_rem_pio2f(x,y); + n = rem_pio2f(x,y); return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even -1 -- n odd */ }