From: Richard Biener <richard.guenther@gmail.com>
To: Jan Hubicka <hubicka@ucw.cz>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: generic retuning part 1 - x86-tune-costs update
Date: Thu, 30 Nov 2017 18:43:00 -0000 [thread overview]
Message-ID: <FDBDC4A3-E4F3-4923-8689-DFE20FF8D312@gmail.com> (raw)
In-Reply-To: <20171130181412.GA36992@kam.mff.cuni.cz>
On November 30, 2017 7:14:12 PM GMT+01:00, Jan Hubicka <hubicka@ucw.cz> wrote:
>>
>> I have benchmarked this quite thoroughly while switching the defaults
>for Core
>> and Zen. Disabling alignment is pretty much consistent for
>specfp/int for
>> 2000,2006 and 2017 (last is Zen only) and quite consistent one. I
>will analyze
>> fma3d. It did not show with the alignment change alone, so it may be
>related
>> to other costs or just bad luck.
>
>I have opened https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83232 for
>that.
>The problem is that SLP gives up vectorization when it sees vectorized
>used
>in the same basic block. Preivously there was alignment prologue while
>now
>we fully unroll the loop. Missed SLP introduce memory mismatch stall.
>
>I am bit lost on why SLP gives up though.
I will have a look - it shouldn't give up so easily. Maybe it's a costing issue.
Richard.
>Honza
prev parent reply other threads:[~2017-11-30 18:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-30 9:54 Jan Hubicka
2017-11-30 11:03 ` Richard Biener
2017-11-30 15:09 ` Jan Hubicka
2017-11-30 18:20 ` Jan Hubicka
2017-11-30 18:43 ` Richard Biener [this message]
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