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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/59747] [4.9 Regression] wrong code at -Os and above on x86_64-linux-gnu in 64-bit mode
Date: Fri, 10 Jan 2014 11:05:00 -0000 [thread overview]
Message-ID: <bug-59747-4-P9xCPqQG1c@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-59747-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59747
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Marek Polacek from comment #2)
> I think the problem is in setting the value of e. With -O in .gimple we
> have:
> e.2 = e;
> e.3 = e.2;
> e.4 = e.3 + -1;
> e = e.4;
> while with -O2:
> e.2 = e;
> e.3 = e.2;
> e.4 = (unsigned short) e.3;
> D.1762 = e.4 + 65535;
> e.5 = (short int) D.1762;
> e = e.5;
That's -fstrict-overflows effect I think, but not the issue. "Fixed" by
-fno-ree.
next prev parent reply other threads:[~2014-01-10 11:05 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-10 6:19 [Bug tree-optimization/59747] New: " su at cs dot ucdavis.edu
2014-01-10 8:48 ` [Bug tree-optimization/59747] [4.9 Regression] " mpolacek at gcc dot gnu.org
2014-01-10 10:05 ` mpolacek at gcc dot gnu.org
2014-01-10 10:17 ` mpolacek at gcc dot gnu.org
2014-01-10 10:58 ` jakub at gcc dot gnu.org
2014-01-10 11:05 ` rguenth at gcc dot gnu.org [this message]
2014-01-10 11:08 ` jakub at gcc dot gnu.org
2014-01-10 13:14 ` jakub at gcc dot gnu.org
2014-01-10 16:25 ` law at redhat dot com
2014-01-10 17:14 ` law at redhat dot com
2014-01-10 17:56 ` law at redhat dot com
2014-01-15 13:11 ` trippels at gcc dot gnu.org
2014-01-15 18:14 ` law at gcc dot gnu.org
2014-01-15 18:14 ` law at redhat dot com
2014-01-16 20:11 ` dominiq at lps dot ens.fr
2014-01-16 20:12 ` dominiq at lps dot ens.fr
2014-01-16 20:12 ` dominiq at lps dot ens.fr
2014-01-16 20:20 ` jakub at gcc dot gnu.org
2014-01-16 21:05 ` dominiq at lps dot ens.fr
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