From: Jan Hubicka <hubicka@ucw.cz>
To: Richard Biener <richard.guenther@gmail.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: generic retuning part 1 - x86-tune-costs update
Date: Thu, 30 Nov 2017 18:20:00 -0000 [thread overview]
Message-ID: <20171130181412.GA36992@kam.mff.cuni.cz> (raw)
In-Reply-To: <20171130143401.GB2770@kam.mff.cuni.cz>
>
> 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.
Honza
next prev parent reply other threads:[~2017-11-30 18:14 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 [this message]
2017-11-30 18:43 ` Richard Biener
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20171130181412.GA36992@kam.mff.cuni.cz \
--to=hubicka@ucw.cz \
--cc=gcc-patches@gcc.gnu.org \
--cc=richard.guenther@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).