public inbox for gcc-prs@sourceware.org help / color / mirror / Atom feed
From: Jan Hubicka <jh@suse.cz> To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, Subject: Re: optimization/10155: [3.3/3.4 regression] gcc -O2/-O3 uses excessive amount of memory Date: Fri, 02 May 2003 13:26:00 -0000 [thread overview] Message-ID: <20030502132600.28495.qmail@sources.redhat.com> (raw) The following reply was made to PR optimization/10155; it has been noted by GNATS. From: Jan Hubicka <jh@suse.cz> To: Steven Bosscher <s.bosscher@student.tudelft.nl> Cc: p.van-hoof@qub.ac.uk, gcc-gnats@gcc.gnu.org, gcc-bugs@gcc.gnu.org, nobody@gcc.gnu.org, gcc-prs@gcc.gnu.org, jh@suse.de, rakdver@atrey.karlin.mff.cuni.cz Subject: Re: optimization/10155: [3.3/3.4 regression] gcc -O2/-O3 uses excessive amount of memory Date: Fri, 2 May 2003 15:25:16 +0200 > http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10155 > > How much of this can be explained with Kaveh's physmem > patch? IIRC that patch is not in 3.2, and the increase > in memory consumption at -O2 may be a result of that > patch. > > The increase in memory at -O3 is a result of unit at a > time compilation (which is why I CC you, Honza). You > can check that by compiling with -O2 + all flags enabled > at -O3 except -funit-at-a-time: > > ./cc1 10155.c -quiet -ftime-report -O2 > TOTAL : 24.74 0.74 26.24 > > ./cc1 10155.c -quiet -ftime-report -O2 -funswitch-loops > -frename-registers -finline-functions > TOTAL : 31.49 0.59 33.87 > > Loop unswitching is responsible for most of the compile Zdenek, this really ought not to happen, what is going on? > time increase. > Now add -funit-at-a-time, and kabooooom! you lose. > > Apparently unit-at-a-time should still honor some size > constraints, and it does not in its current form. It should be more problem of inlining heuristics, than unit-at-a-time (ie unit-at-a-time enables more inlining oppurtunities but it is inlining heuristic mistake to take so many of them). Or perhaps we manage to flatten functions called once into one extraordinarily large function body and give up on it. I will try to investigate it, but my current priority is to get unit-at-a-time working on C++. Fixing this testcase should be easy then :) Honza > > Greetz > Steven > >
next reply other threads:[~2003-05-02 13:26 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2003-05-02 13:26 Jan Hubicka [this message] -- strict thread matches above, loose matches on Subject: below -- 2003-05-06 20:46 Peter van Hoof 2003-05-02 19:16 Zdenek Dvorak 2003-05-02 17:46 Zdenek Dvorak 2003-05-02 11:06 Steven Bosscher 2003-04-15 8:51 ebotcazou
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=20030502132600.28495.qmail@sources.redhat.com \ --to=jh@suse.cz \ --cc=gcc-prs@gcc.gnu.org \ --cc=nobody@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).