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From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/100711] Miss optimization for pandn
Date: Tue, 25 May 2021 06:52:06 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D100711

--- Comment #4 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Hongtao.liu from comment #3)
>=20
> (In reply to Segher Boessenkool from comment #2)
> > (In reply to Richard Biener from comment #1)
> > > I suppose we're confused about the vec_duplicate.  Would generally=20
> Even w/ canonical RTL, i think a combine splitter is also needed here, the
> canonical RTL only helps combine/forwprop to match more possibility but
> won't split patterns by itselies.

I was wrong, i thought combine only support n->1 combining, but actually
pass_combine also support 3->2 combining which means a define_split is not
needed here.=