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Re: Why doesn't GCC generate conditional move for COND_EXPR?

From: Andrew Pinski <pinskia at gmail dot com>
To: Richard Guenther <richard dot guenther at gmail dot com>
Cc: Bingfeng Mei <bmei at broadcom dot com>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
Date: Mon, 24 Oct 2011 09:19:36 -0700
Subject: Re: Why doesn't GCC generate conditional move for COND_EXPR?
References: <7FB04A5C213E9943A72EE127DB74F0ADD15FEADD80@SJEXCHCCR02.corp.ad.broadcom.com> <CAFiYyc0xGcf5iphRq2Z59-R4GG6wUvWHMuP_GfCUTSqyokZD+w@mail.gmail.com>

On Mon, Oct 24, 2011 at 7:00 AM, Richard Guenther
<richard.guenther@gmail.com> wrote:
> On Mon, Oct 24, 2011 at 2:55 PM, Bingfeng Mei <bmei@broadcom.com> wrote:
>> Hello,
>> I noticed that COND_EXPR is not expanded to conditional move
>> as MIN_EXPR/MAX_EXPR are (assuming movmodecc is available).
>> I wonder why not?
>>
>> I have some loop that fails tree vectorization, but still contains
>> COND_EXPR from tree ifcvt pass. In the end, the generated code
>> is worse than if I don't turned -ftree-vectorize on. ÂThis
>> is on our private port.
>
> Because nobody touched COND_EXPR expansion since ages.

I have a patch which I will be submitting next week or so that does
this expansion correctly.  In fact I have a few patches which improves
the generation of COND_EXPR in simple cases (in PHI-OPT).

Thanks,
Andrew Pinski

Follow-Ups:
- RE: Why doesn't GCC generate conditional move for COND_EXPR?
  - From: Bingfeng Mei

References:
- Why doesn't GCC generate conditional move for COND_EXPR?
  - From: Bingfeng Mei
- Re: Why doesn't GCC generate conditional move for COND_EXPR?
  - From: Richard Guenther

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