Date: Mon, 21 Nov 2005 00:38:22 +0000 (UTC) From: Bruce Evans <bde@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/lib/msun/src k_tanf.c Message-ID: <200511210038.jAL0cMhO076845@repoman.freebsd.org>
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bde 2005-11-21 00:38:22 UTC
FreeBSD src repository
Modified files:
lib/msun/src k_tanf.c
Log:
Use double precision to simplify and optimize a long division.
On athlons, this gives a speedup of 10-20% for tanf() on uniformly
distributed args in [-2Pi, 2Pi]. (It only directly applies for 43%
of the args and gives a 16-20% speedup for these (more for AXP than
A64) and this gives an overall speedup of 10-12% which is all that it
should; however, it gives an overall speedup of 17-20% with gcc-3.3
on AXP-A64 by mysteriously effected cases where it isn't executed.)
I originally intended to use double precision for all internals of
float trig functions and will probably still do this, but benchmarking
showed that converting to double precision and back is a pessimization
in cases where a simple float precision calculation works, so it may
be optimal to switch precisions only when using extra precision is
much simpler.
Revision Changes Path
1.14 +1 -15 src/lib/msun/src/k_tanf.c
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