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From: Richard Biener <richard.guenther@gmail.com>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Hongyu Wang <hongyu.wang@intel.com>,
	gcc-patches@gcc.gnu.org, dje.gcc@gmail.com
Subject: Re: [PATCH] rs6000: Adjust loop_unroll_adjust to match middle-end change [PR 107692]
Date: Tue, 22 Nov 2022 10:00:28 +0100	[thread overview]
Message-ID: <CAFiYyc3Ui9ivMvV3i2tXwUtoT=v4b017hB6kh=7xfE4XJ_yCoQ@mail.gmail.com> (raw)
In-Reply-To: <20221118144600.GZ25951@gate.crashing.org>

On Fri, Nov 18, 2022 at 3:47 PM Segher Boessenkool
<segher@kernel.crashing.org> wrote:
>
> [ Please cc: me and Ke Wen on rs6000 patches ]
>
> On Thu, Nov 17, 2022 at 07:54:29AM +0800, Hongyu Wang wrote:
> > r13-3950-g071e428c24ee8c enables O2 small loop unrolling, but it breaks
> > -fno-unroll-loops for rs6000 with loop_unroll_adjust hook. Adjust the
> > option handling and target hook accordingly.
>
> NAK.
>
> This is wrong.  -munroll-only-small-loops does not enable loop
> unrolling; doing that with a machine flag is completely unmaintainable,
> also for people using different targets.

I suggested that because doing it fully in the backend by twiddling
-funroll-loops is unmaintainable as well.

> Something in your patch was wrong, please fix that (or revert the
> patch).  You should not have to touch config/rs6000/ at all.

Sure something is wrong, but I think there's the opportunity to
simplify rs6000/ and s390x/, the only other two implementors of
the hook used.

Richard.

>
> Segher

  reply	other threads:[~2022-11-22  9:00 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-16 23:54 Hongyu Wang
2022-11-18 14:46 ` Segher Boessenkool
2022-11-22  9:00   ` Richard Biener [this message]
2022-11-23  1:53     ` Hongyu Wang
2022-11-23 20:02       ` Richard Biener

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