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From: "glisse at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/55016] request for specific builtins for rcp and rsqrt
Date: Mon, 22 Oct 2012 18:57:00 -0000	[thread overview]
Message-ID: <bug-55016-4-xfdxflLqkH@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-55016-4@http.gcc.gnu.org/bugzilla/>


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55016

--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> 2012-10-22 18:56:42 UTC ---
(In reply to comment #0)
> void v() {
>   for(int i=0; i!=1024; ++i)
>     v0[i] = rsqrtf(v1[i]);
> }

Doesn't writing
v0[i] = 1 / sqrtf(v1[i])
work with suitable fast-math flags? It still produces an extra iteration to
refine the result, do we want a -ffaster-math?


  reply	other threads:[~2012-10-22 18:57 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-22  6:44 [Bug tree-optimization/55016] New: " vincenzo.innocente at cern dot ch
2012-10-22 18:57 ` glisse at gcc dot gnu.org [this message]
2012-10-23  5:19 ` [Bug tree-optimization/55016] " vincenzo.innocente at cern dot ch
2012-10-23  6:12 ` glisse at gcc dot gnu.org

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