public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "oleg.smolsky at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/50182] New: Performance degradation from gcc 4.1 (x86_64) Date: Wed, 24 Aug 2011 21:27:00 -0000 [thread overview] Message-ID: <bug-50182-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50182 Bug #: 50182 Summary: Performance degradation from gcc 4.1 (x86_64) Classification: Unclassified Product: gcc Version: 4.6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned@gcc.gnu.org ReportedBy: oleg.smolsky@gmail.com G++ 4.6 emits slower code based on the following set of benchmarks: http://stlab.adobe.com/performance/ The discussion thread is here: http://gcc.gnu.org/ml/gcc/2011-07/threads.html#00506 http://gcc.gnu.org/ml/gcc/2011-08/threads.html#00411 I digested one of the tests down to a single short case (see attachments): http://gcc.gnu.org/ml/gcc/2011-08/msg00391.html g++ 4.1 (1.35 sec, 1185M ops/s): .text:0000000000400FE0 loc_400FE0: .text:0000000000400FE0 movzx eax, ds:data8[rdx] .text:0000000000400FE7 add rdx, 1 .text:0000000000400FEB add eax, 0Ah .text:0000000000400FEE cmp rdx, 1F40h .text:0000000000400FF5 lea ecx, [rax+rcx] .text:0000000000400FF8 jnz short loc_400FE0 g++ 4.6 (2.86s, 563M ops/s) : .text:0000000000400D90 loc_400D90: .text:0000000000400D90 add eax, 0Ah .text:0000000000400D93 add al, [rdx] .text:0000000000400D95 add rdx, 1 .text:0000000000400D99 cmp rdx, 503480h .text:0000000000400DA0 jnz short loc_400D90 P.S. setting the component to C++. Optimizer?
next reply other threads:[~2011-08-24 21:23 UTC|newest] Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-08-24 21:27 oleg.smolsky at gmail dot com [this message] 2011-08-24 22:30 ` [Bug target/50182] " oleg.smolsky at gmail dot com 2011-08-25 0:14 ` xinliangli at gmail dot com 2011-08-25 0:52 ` xinliangli at gmail dot com 2011-08-25 9:00 ` jakub at gcc dot gnu.org 2011-08-25 15:21 ` oleg.smolsky at gmail dot com 2011-08-25 15:29 ` oleg.smolsky at gmail dot com 2011-08-25 16:18 ` hjl.tools at gmail dot com 2011-08-25 16:26 ` xinliangli at gmail dot com 2011-08-25 16:49 ` oleg.smolsky at gmail dot com 2011-08-25 22:48 ` oleg.smolsky at gmail dot com 2011-08-26 7:12 ` oleg.smolsky at gmail dot com 2011-08-30 20:37 ` matt at use dot net 2011-09-15 16:57 ` oleg at smolsky dot net 2011-09-15 17:39 ` xinliangli at gmail dot com 2011-10-21 23:02 ` xinliangli at gmail dot com 2011-10-24 18:28 ` oleg at smolsky dot net 2011-10-24 18:28 ` oleg at smolsky dot net 2011-10-24 18:33 ` oleg at smolsky dot net 2011-10-24 19:34 ` xinliangli at gmail dot com 2011-10-24 19:50 ` oleg at smolsky dot net 2011-10-24 19:59 ` xinliangli at gmail dot com 2011-10-24 21:12 ` oleg at smolsky dot net 2011-10-24 23:00 ` xinliangli at gmail dot com 2011-10-24 23:03 ` xinliangli at gmail dot com 2012-01-10 18:07 ` oleg at smolsky dot net 2012-01-11 9:43 ` rguenth at gcc dot gnu.org 2012-01-11 17:27 ` xinliangli at gmail dot com 2012-03-02 0:56 ` oleg at smolsky dot net 2012-03-02 8:08 ` jakub at gcc dot gnu.org 2012-03-02 8:23 ` oleg at smolsky dot net 2012-03-02 8:29 ` jakub at gcc dot gnu.org 2012-03-02 9:14 ` jakub at gcc dot gnu.org 2012-03-03 2:20 ` oleg at smolsky dot net 2012-03-03 2:47 ` oleg at smolsky dot net 2012-03-03 3:00 ` oleg at smolsky dot net 2012-03-06 16:34 ` oleg at smolsky dot net 2012-03-06 17:27 ` jakub at gcc dot gnu.org 2012-03-06 19:40 ` oleg at smolsky dot net
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-50182-4@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: linkBe 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).