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From: "tnfchris at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/113163] [14 Regression][GCN] ICE in
 vect_peel_nonlinear_iv_init, at tree-vect-loop.cc:9420
Date: Tue, 02 Jan 2024 11:35:34 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113163

--- Comment #12 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
(In reply to Andrew Stubbs from comment #11)
> (In reply to Tamar Christina from comment #7)
> > This seems to happen because the vectorizer decides to use partial vect=
ors
> > to vectorize the loop and the target picks a nonlinear induction step w=
hich
> > we can't support for early breaks.
>=20
> In which hook is this selected?
>=20
> I'm not aware of this being a deliberate choice we made...

I haven't looked into why on the target we get a nonlinear induction (mostly
because I don't know much about the target). I however wasn't able to repro=
duce
it on SVE and x86_64 even when forcing partial vectors.

So I guess it's more accurate to say "something about the target" is making=
 the
vectorizer pick a nonlinear induction.  most likely missing support for
something.

Note that the testcase does work if partial vectors is turned off. So It sh=
ould
work fine if the vectorizer retries without partial vectors.

waiting for Richi to come back from holiday to review the patch and should =
be
fixed.=