public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/62041] vector fneg codegen uses a subtract instead of an xor (x86-64)
Date: Thu, 07 Aug 2014 09:42:00 -0000 [thread overview]
Message-ID: <bug-62041-4-Bl9KonYA5g@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-62041-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62041
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Status|UNCONFIRMED |NEW
Last reconfirmed| |2014-08-07
Component|target |rtl-optimization
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
That's because _mm_sub_ps is a builtin during gimple opts and on RTL we
generally don't do very many FP related optimizations (especially on vectors).
Confirmed.
(insn 6 5 7 (set (reg:V4SF 87)
(mem/u/c:V4SF (symbol_ref/u:DI ("*.LC0") [flags 0x2]) [2 S16 A128]))
/usr/lib64/gcc/x86_64-suse-linux/4.9/include/xmmintrin.h:189 -1
(expr_list:REG_EQUAL (const_vector:V4SF [
(const_double:SF -0.0 [-0x0.0p+0])
(const_double:SF -0.0 [-0x0.0p+0])
(const_double:SF -0.0 [-0x0.0p+0])
(const_double:SF -0.0 [-0x0.0p+0])
])
(nil)))
(insn 7 6 8 (set (reg:V4SF 86)
(minus:V4SF (reg:V4SF 87)
(reg/v:V4SF 85 [ x ])))
/usr/lib64/gcc/x86_64-suse-linux/4.9/include/xmmintrin.h:189 -1
(nil))
could be optimized guarded with the appropriate flags (signed zeros?
nans/infs?).
next prev parent reply other threads:[~2014-08-07 9:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-06 19:06 [Bug target/62041] New: " spatel at rotateright dot com
2014-08-07 9:42 ` rguenth at gcc dot gnu.org [this message]
2014-08-07 10:06 ` [Bug rtl-optimization/62041] " glisse at gcc dot gnu.org
2014-08-07 10:10 ` glisse at gcc dot gnu.org
2014-08-07 10:22 ` glisse at gcc dot gnu.org
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=bug-62041-4-Bl9KonYA5g@http.gcc.gnu.org/bugzilla/ \
--to=gcc-bugzilla@gcc.gnu.org \
--cc=gcc-bugs@gcc.gnu.org \
/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).