public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/99396] std::rotl and std::rotr do not invoke intrinsics, leading to serious performance issues
Date: Fri, 05 Mar 2021 00:05:10 +0000 [thread overview]
Message-ID: <bug-99396-4-5HfjLnjUD8@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-99396-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99396
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|libstdc++ |tree-optimization
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2021-03-05
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
return std::rotr(v,((unsigned int)t)&63);
Fixes the problem ....
int a = std::abs(t);
a &= 63;
return std::rotr(v,a);
Also improves the situtation.
I am thinking the std::rotr could be rewritten or we could optimize this at the
tree level into the almost the intrinsics.
Note I think I Might have gotten the above incorrect a little bit.
next prev parent reply other threads:[~2021-03-05 0:05 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 23:09 [Bug libstdc++/99396] New: " unlvsur at live dot com
2021-03-05 0:05 ` pinskia at gcc dot gnu.org [this message]
2021-03-05 0:06 ` [Bug tree-optimization/99396] std::rotl and std::rotr Does not convert into ROTATE on the gimple level pinskia at gcc dot gnu.org
2021-03-05 2:08 ` unlvsur at live dot com
2021-03-05 3:12 ` pinskia at gcc dot gnu.org
2021-03-05 3:18 ` unlvsur at live dot com
2021-03-05 8:25 ` redi at gcc dot gnu.org
2021-03-05 9:36 ` jakub at gcc dot gnu.org
2021-03-05 9:44 ` jakub at gcc dot gnu.org
2021-03-05 9:50 ` jakub at gcc dot gnu.org
2021-03-05 10:38 ` jakub at gcc dot gnu.org
2021-03-05 10:47 ` redi at gcc dot gnu.org
2021-03-05 10:52 ` jakub at gcc dot gnu.org
2021-03-05 11:02 ` jakub at gcc dot gnu.org
2021-03-05 11:59 ` unlvsur at live dot com
2021-03-05 12:03 ` jakub at gcc dot gnu.org
2021-03-05 12:04 ` jakub at gcc dot gnu.org
2021-03-05 12:08 ` unlvsur at live dot com
2021-03-05 12:09 ` unlvsur at live dot com
2021-03-05 12:12 ` unlvsur at live dot com
2021-03-06 10:12 ` cvs-commit at gcc dot gnu.org
2021-03-06 10:13 ` jakub 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-99396-4-5HfjLnjUD8@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).