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[Bug tree-optimization/55016] request for specific builtins for rcp and rsqrt
- From: "glisse at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 22 Oct 2012 18:56:42 +0000
- Subject: [Bug tree-optimization/55016] request for specific builtins for rcp and rsqrt
- Auto-submitted: auto-generated
- References: <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?