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From: Steve Ellcey <sellcey@cavium.com>
To: NightStrike <nightstrike@gmail.com>, joel@rtems.org
Cc: Paul Menzel <pmenzel+gcc.gnu.org@molgen.mpg.de>,
	"gcc@gcc.gnu.org"	 <gcc@gcc.gnu.org>
Subject: Re: How to get GCC on par with ICC?
Date: Fri, 22 Jun 2018 00:48:00 -0000	[thread overview]
Message-ID: <1529622309.19200.12.camel@cavium.com> (raw)
In-Reply-To: <CAF1jjLuoNjPrpWQL4fiwCBs2-xJX2MR7GDdhWYPhWGvXdKG8kA@mail.gmail.com>

On Wed, 2018-06-20 at 17:11 -0400, NightStrike wrote:
> 
> If I could perhaps jump in here for a moment...  Just today I hit upon
> a series of small (in lines of code) loops that gcc can't vectorize,
> and intel vectorizes like a madman.  They all involve a lot of heavy
> use of std::vector<std::vector<float>>.  Comparisons were with gcc
> 8.1, intel 2018.u1, an AMD Opteron 6386 SE, with the program running
> as sched_FIFO, mlockall, affinity set to its own core, and all
> interrupts vectored off that core.  So, as close to not-noisy as
> possible.

There are a quite a number of bugzilla reports with examples where GCC
does not vectorize a loop.  I wonder if this example is related to PR
61247.

Steve Ellcey

  parent reply	other threads:[~2018-06-21 23:05 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-06 15:57 Paul Menzel
2018-06-06 16:14 ` Joel Sherrill
2018-06-06 16:20   ` Paul Menzel
2018-06-20 22:42   ` NightStrike
2018-06-21  9:20     ` Richard Biener
2018-06-22  0:48     ` Steve Ellcey [this message]
2018-06-06 16:22 ` Bin.Cheng
2018-06-06 18:31 ` Dmitry Mikushin
2018-06-06 21:10   ` Ryan Burn
2018-06-07 10:02     ` Richard Biener
2018-06-06 22:43   ` Zan Lynx
2018-06-07  9:54     ` Richard Biener
2018-06-07 10:06 ` Richard Biener
2018-06-08 22:08   ` Steve Ellcey
2018-06-09 15:32     ` Marc Glisse
2018-06-11 14:50     ` Martin Jambor
2018-06-22 22:41       ` Szabolcs Nagy
2018-06-15 11:48 Wilco Dijkstra
2018-06-15 17:03 ` Jeff Law
2018-06-15 18:01   ` Joseph Myers

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