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From: "guojiufu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/95018] [10/11 Regression] Excessive unrolling for
 Fortran library array handling
Date: Wed, 13 May 2020 11:24:41 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D95018

--- Comment #33 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #32)
> Note I don't think the unrolling is excessive - store motion then applying
> to all count[] and all computations hoisted out of the loop may be a bit
> too much for register pressure though, especially since we're using
> flag-based store-motion.  But it causes the stores to be materialized
> on all exits of the loop which means we end up with N*N conditional store=
s :/

In general, it may not very aggressive for param_max_peel_branches =3D 31,
param_max_completely_peel_times =3D 16.=20
For in_pack_i4.c, the loop is at most 13+1 times and then be unrolled. While
for the loop, unrolling increases size and does not help performance.

>=20
> I guess SM could be improved here.


Thanks all!=