------- Comment #1 from burnus at gcc dot gnu dot org 2007-06-18 15:03 ------- Initial suggestion, see: http://gcc.gnu.org/ml/gcc-patches/2007-06/msg01068.html
Richard's remark: http://gcc.gnu.org/ml/gcc-patches/2007-06/msg01224.html > Two NR steps don't make sense, they wouldn't improve accuracy because of the > extra roundings we get for the NR. And of course it would be slower. (However, two NR are said to be enough for double precision. I don't know whether doing rsqrt+(2x NR) is faster than 1/sqrt() for double or not.) Related - closed - PRs: PR 31723 - Use reciprocal and reciprocal square root with -ffast-math (FIXED) PR 32352 - Using rsqrt, Polyhedron's aermod test crashes (WONTFIX) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32392
