From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 854843858C2C; Fri, 29 Apr 2022 19:20:18 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 854843858C2C From: "joseph at codesourcery dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/105428] compilation never (?) finishes with __builtin_casinl() and __builtin_csqrtl() with -O -mlong-double-128 Date: Fri, 29 Apr 2022 19:20:18 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 12.0 X-Bugzilla-Keywords: compile-time-hog, memory-hog X-Bugzilla-Severity: normal X-Bugzilla-Who: joseph at codesourcery dot com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 29 Apr 2022 19:20:18 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105428 --- Comment #4 from joseph at codesourcery dot com --- If you can identify specific arguments passed to mpc_asin for which it is=20 excessively slow, that should be reported as an MPC bug. Computing correctly rounded mpc_asin shouldn't need to be that slow -=20 provided the algorithm used is appropriate to the input value. See for=20 example how glibc implements casin / casinh / cacos / cacosh. Or=20 https://dl.acm.org/doi/10.1145/275323.275324 (Hull et al, Implementing the= =20 complex arcsine and arccosine functions using exception handling, ACM TOMS= =20 vol. 23 no. 3 (Sep 1997) pp 299-335). That may require several different=20 algorithms to be implemented, but each such algorithm is straightforward.= =20=20 That's different from the case of Bessel functions of high order - for=20 which there is some literature about computational techniques that=20 shouldn't take time proportional to the order, but where the algorithms=20 are certainly a lot more complicated.=