From owner-freebsd-hackers@freebsd.org Sun Sep 20 00:25:09 2020 Return-Path: Delivered-To: freebsd-hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 19C6B3F446C; Sun, 20 Sep 2020 00:25:09 +0000 (UTC) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu [128.95.76.21]) (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 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "troutmask", Issuer "troutmask" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Bv7d014F3z3TQ7; Sun, 20 Sep 2020 00:25:07 +0000 (UTC) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (localhost [127.0.0.1]) by troutmask.apl.washington.edu (8.16.1/8.16.1) with ESMTPS id 08K0P6sW047957 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sat, 19 Sep 2020 17:25:06 -0700 (PDT) (envelope-from sgk@troutmask.apl.washington.edu) Received: (from sgk@localhost) by troutmask.apl.washington.edu (8.16.1/8.16.1/Submit) id 08K0P68C047956; Sat, 19 Sep 2020 17:25:06 -0700 (PDT) (envelope-from sgk) Date: Sat, 19 Sep 2020 17:25:06 -0700 From: Steve Kargl To: freebsd-hackers@freebsd.org, freebsd-current@freebsd.org Subject: [PATCH] libm -- optimize __ldexp_cexp[f] Message-ID: <20200920002506.GA47948@troutmask.apl.washington.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspamd-Queue-Id: 4Bv7d014F3z3TQ7 X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=washington.edu (policy=none); spf=none (mx1.freebsd.org: domain of sgk@troutmask.apl.washington.edu has no SPF policy when checking 128.95.76.21) smtp.mailfrom=sgk@troutmask.apl.washington.edu X-Spamd-Result: default: False [-1.48 / 15.00]; RCVD_TLS_ALL(0.00)[]; ARC_NA(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_HAM_LONG(-0.37)[-0.371]; MIME_GOOD(-0.10)[text/plain]; TO_DN_NONE(0.00)[]; NEURAL_HAM_MEDIUM(-0.56)[-0.561]; NEURAL_HAM_SHORT(-0.55)[-0.552]; RCPT_COUNT_TWO(0.00)[2]; R_SPF_NA(0.00)[no SPF record]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:73, ipnet:128.95.0.0/16, country:US]; RCVD_COUNT_TWO(0.00)[2]; MAILMAN_DEST(0.00)[freebsd-hackers,freebsd-current]; DMARC_POLICY_SOFTFAIL(0.10)[washington.edu : No valid SPF, No valid DKIM, none] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 20 Sep 2020 00:25:09 -0000 The following patch is an opimization for he kernels used by cexp(x) and cexpf(x). . Use sincos[f] instead of a call to cos[f] and a call to sin[f]. . While here, alphabetize declaration. --- /usr/src/lib/msun/src/k_exp.c 2019-02-23 07:45:03.879997000 -0800 +++ src/k_exp.c 2019-12-26 08:15:30.109189000 -0800 @@ -88,7 +88,7 @@ double complex __ldexp_cexp(double complex z, int expt) { - double x, y, exp_x, scale1, scale2; + double c, exp_x, s, scale1, scale2, x, y; int ex_expt, half_expt; x = creal(z); @@ -105,6 +105,7 @@ half_expt = expt - half_expt; INSERT_WORDS(scale2, (0x3ff + half_expt) << 20, 0); - return (CMPLX(cos(y) * exp_x * scale1 * scale2, - sin(y) * exp_x * scale1 * scale2)); + sincos(y, &s, &c); + return (CMPLX(c * exp_x * scale1 * scale2, + s * exp_x * scale1 * scale2)); } --- /usr/src/lib/msun/src/k_expf.c 2019-02-23 07:45:03.881215000 -0800 +++ src/k_expf.c 2019-12-26 08:15:30.109818000 -0800 @@ -71,7 +71,7 @@ float complex __ldexp_cexpf(float complex z, int expt) { - float x, y, exp_x, scale1, scale2; + float c, exp_x, s, scale1, scale2, x, y; int ex_expt, half_expt; x = crealf(z); @@ -84,6 +84,7 @@ half_expt = expt - half_expt; SET_FLOAT_WORD(scale2, (0x7f + half_expt) << 23); - return (CMPLXF(cosf(y) * exp_x * scale1 * scale2, - sinf(y) * exp_x * scale1 * scale2)); + sincosf(y, &s, &c); + return (CMPLXF(c * exp_x * scale1 * scale2, + s * exp_x * scale1 * scale2)); } -- Steve