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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/103797] Clang vectorized LightPixel while GCC
 does not
Date: Thu, 23 Dec 2021 09:15:40 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103797

--- Comment #15 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Uro=C5=A1 Bizjak from comment #12)
> (In reply to Jakub Jelinek from comment #10)
> > At least on your short testcase clang doesn't use divps either.
> > We do support mulv2sf3, addv2sf3 etc. but not divv2sf3 I bet because wi=
th
> > TARGET_MMX_WITH_SSE it would divide by zero in the 3rd and 4th elts,
> > but perhaps we could insert 1.0f, 1.0f into those elements of the divis=
or
> > before using divps?
>=20
> It could be done, but I was under impression that the sequence to load 1.=
0f
> into topmost elements nullifies the benefit of operation to divide two

Sure, so perhaps we should somewhat increase the vectorization cost of V2SF=
mode
division so that we would use it only if it is part of longer sequences?=