public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
From: "soap at gentoo dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/94617] Simple if condition not optimized
Date: Thu, 16 Apr 2020 12:18:03 +0000 [thread overview]
Message-ID: <bug-94617-4-RiVgc3dQl7@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-94617-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94617
--- Comment #5 from David Seifert <soap at gentoo dot org> ---
(In reply to Richard Biener from comment #3)
> Note the RTL if-conversion pass doesn't recognize what we present to it.
> If you alter initial RTL expansion via -fno-tree-ter (not recommended in
> general)
> we produce a more 1:1 translation of the code as
>
> _Z16vanilla_bandpassiiiPKcS0_:
> .LFB0:
> .cfi_startproc
> movl %esi, %r9d
> cmpl %edx, %edi
> setle %sil
> cmpl %r9d, %edx
> setl %al
> testb %al, %sil
> movq %rcx, %rax
> cmovne %r8, %rax
> ret
>
> which I wouldn't expect to execute faster though.
just benchmarked the code on an oldish Ivybridge. GCC with vanilla_bandpass is
2.1x slower than GCC with funky_bandpass, and GCC with funky_bandpass is 12%
slower than Clang with vanilla_bandpass.
next prev parent reply other threads:[~2020-04-16 12:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-16 11:28 [Bug tree-optimization/94617] New: " soap at gentoo dot org
2020-04-16 11:57 ` [Bug tree-optimization/94617] " rguenth at gcc dot gnu.org
2020-04-16 12:02 ` soap at gentoo dot org
2020-04-16 12:10 ` rguenth at gcc dot gnu.org
2020-04-16 12:17 ` rguenth at gcc dot gnu.org
2020-04-16 12:18 ` soap at gentoo dot org [this message]
2020-04-16 12:47 ` jakub at gcc dot gnu.org
2020-04-16 13:11 ` rguenth at gcc dot gnu.org
2021-07-19 3:40 ` [Bug target/94617] " pinskia at gcc dot gnu.org
2022-11-26 20:43 ` pinskia at gcc dot gnu.org
2023-06-25 22:29 ` pinskia at gcc dot gnu.org
2023-06-25 22:45 ` pinskia 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-94617-4-RiVgc3dQl7@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).