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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/58727] Sub-optimal code for bit clear/set sequence
Date: Mon, 14 Oct 2013 21:49:00 -0000 [thread overview]
Message-ID: <bug-58727-4-jO0Fo5O8Zb@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-58727-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58727
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|rtl-optimization |tree-optimization
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I see the issue:
clear_set produces:
D.1381_2 = a_1(D) & 0xffbffffd;
D.1380_3 = D.1381_2 | 2;
While clear_set_inline produces:
D.1381_2 = a_1(D) & 0xffbfffff;
D.1380_3 = D.1381_2 | 2;
The lower two bits make GCC optimize it easier.
I think the issue is in fold-const.c as .original is already includes the ~0x2
in the and part.
next prev parent reply other threads:[~2013-10-14 21:49 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-14 20:01 [Bug tree-optimization/58727] New: " niels at penneman dot org
2013-10-14 20:18 ` [Bug rtl-optimization/58727] " pinskia at gcc dot gnu.org
2013-10-14 21:43 ` niels at penneman dot org
2013-10-14 21:49 ` pinskia at gcc dot gnu.org [this message]
2013-10-14 22:08 ` [Bug tree-optimization/58727] " pinskia at gcc dot gnu.org
2013-10-15 7:06 ` jakub at gcc dot gnu.org
2013-10-15 8:35 ` niels at penneman dot org
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